Non-Abelian symmetry can increase entanglement entropy. (arXiv:2209.14303v1 [quant-ph]) |

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Shayan Majidy, Aleksander Lasek, David A. Huse, Nicole Yunger Halpern

Fri Sep 30 2022 08:52:12 (9 minutes)

# 1.

The pillars of quantum theory include entanglement and operators’ failure to commute. The Page curve quantifies the bipartite entanglement of a many-body system in a random pure state. This entanglement is known to decrease if one constrains extensive observables that commute with each other (Abelian “charges”). Non-Abelian charges, which fail to commute with each other, are of current interest in quantum thermodynamics. For example, noncommuting charges were shown to reduce entropy-production rates and may enhance finite-size deviations from eigenstate thermalization. Bridging quantum thermodynamics to many-body physics, we quantify the effects of charges’ noncommutation — of a symmetry’s non-Abelian nature — on Page curves. First, we construct two models that are closely analogous but differ in whether their charges commute. We show analytically and numerically that the noncommuting-charge case has more entanglement. Hence charges’ noncommutation can promote entanglement.

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Laura Lewis, Daiwei Zhu, Alexandru Gheorghiu, Crystal Noel, Or Katz, Bahaa Harraz, Qingfeng Wang, Andrew Risinger, Lei Feng, Debopriyo Biswas, Laird Egan, Thomas Vidick, Marko Cetina, Christopher Monroe

Fri Sep 30 2022 08:52:11 (9 minutes)

# 2.

A test of quantumness is a protocol where a classical user issues challenges to a quantum device to determine if it exhibits non-classical behavior, under certain cryptographic assumptions. Recent attempts to implement such tests on current quantum computers rely on either interactive challenges with efficient verification, or non-interactive challenges with inefficient (exponential time) verification. In this paper, we execute an efficient non-interactive test of quantumness on an ion-trap quantum computer. Our results significantly exceed the bound for a classical device’s success.

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Stephen L. Adler

Fri Sep 30 2022 08:52:04 (9 minutes)

# 3.

In an interesting paper, Kundu, Pradhan, and Rosenzweig have obtained a bound on the cosmological constant using high accuracy energy level measurements of Rydberg atoms. We show here that the effective potential they use can be derived from the geodesic equation for the atomic electron, and that this method shows that the energy shifts are computable from the leading cosmological constant contribution to the temporal component of the gravitational metric. To within a small factor, bounds of similar magnitude are obtained from the standard cosmological constant action, in which “dark energy” is taken as a vacuum energy, and from a novel cosmological constant action based on Weyl scaling invariance, in which dark energy is not a vacuum energy. So the Rydberg atom bound does not reveal whether or not the vacuum gravitates.

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Gal Ness, Andrea Alberti, and Yoav Sagi

Thu Sep 29 2022 18:00:00 (15 hours)

# 4.

Author(s): Gal Ness, Andrea Alberti, and Yoav Sagi

Quantum speed limits set the maximal pace of state evolution. Two well-known limits exist for a unitary time-independent Hamiltonian: the Mandelstam-Tamm and Margolus-Levitin bounds. The former restricts the rate according to the state energy uncertainty, while the latter depends on the mean energy …

[Phys. Rev. Lett. 129, 140403] Published Thu Sep 29, 2022

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physics.hist-ph updates on arXiv.org

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Paul Worden, James Overduin

Thu Sep 29 2022 09:34:32 (23 hours)

# 5.

Einstein’s happiest thought was his leap from the observation that a falling person feels no gravity to the realization that gravity might be equivalent to acceleration. It affects all bodies in the same way because it is a property of spacetime — its curvature — not a force propagating through spacetime (like electromagnetic or nuclear forces). When expressed in a way that is manifestly independent of the choice of coordinates, this idea became General Relativity. But the ground for what is now known as the “equivalence principle” was laid long before Einstein, affording a fascinating example of the growth of a scientific idea through the continuous interplay between theory and experiment. That story continues through the present era, with improved techniques and measurements, and in the new environment of space. Theoretically, equivalence is now understood to rank with Lorentz invariance as one of nature’s most fundamental principles. Violations of equivalence are generically predicted by attempts to unify gravity with “non-geometrical” fundamental interactions, but there is no consensus on the form that these violations will take. Experimental tests of equivalence thus face the challenge of striving simultaneously for the highest possible sensitivity and diversity in test materials.

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Wed Sep 28 2022 00:25:50 (2 days)

# 6.

Stoica, Ovidiu Cristinel (2022) Quantum mechanics requires “conspiracy”. [Preprint]

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Wed Sep 28 2022 00:24:10 (2 days)

# 7.

Haueis, Philipp (2022) Revising scientific concepts with multiple meanings: beyond pluralism and eliminativism. In: UNSPECIFIED.

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Tobias Micklitz, Alan Morningstar, Alexander Altland, and David A. Huse

Tue Sep 27 2022 18:00:00 (2 days)

# 8.

Author(s): Tobias Micklitz, Alan Morningstar, Alexander Altland, and David A. Huse

Researchers have calculated the likelihood that a quantum state will decay when its evolution is inhibited by a lack of availability of final states.

[Phys. Rev. Lett. 129, 140402] Published Tue Sep 27, 2022

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Tue Sep 27 2022 07:16:03 (3 days)

# 9.

Zinkernagel, Henrik (2022) Aesthetic Motivation in Quantum Physics: Past and Present. Annalen der Physik, 534 (9). pp. 2200283 (1-6).

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Mon Sep 26 2022 01:05:16 (4 days)

# 10.

Gao, Shan (2022) On the ontologies of quantum theories. [Preprint]

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Mon Sep 26 2022 01:04:22 (4 days)

# 11.

Kish Bar-On, Kati (2022) From Philosophical Traditions to Scientific Developments: Reconsidering the Response to Brouwer’s Intuitionism. [Preprint]

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Mon Sep 26 2022 01:03:59 (4 days)

# 12.

McCoy, C.D. (2022) The Constitution of Weyl’s Pure Infinitesimal World Geometry. HOPOS, 12 (1). pp. 189-208.

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Mon Sep 26 2022 01:02:38 (4 days)

# 13.

Callender, Craig and McCoy, C.D. (2021) Time in Cosmology. The Routledge Companion to Philosophy of Physics. pp. 707-718.

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Sun Sep 25 2022 01:11:50 (5 days)

# 14.

Jalloh, Mahmoud (2022) The Π-Theorem as a Guide to Quantity Symmetries and the Argument Against Absolutism. [Preprint]

]]>Highlighting relations between Wave-particle duality, Uncertainty principle, Phase space and Microstates. (arXiv:2205.08538v2 [quant-ph] UPDATED) |

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physics.hist-ph updates on arXiv.org

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Ravo Tokiniaina Ranaivoson, Voriraza Séraphin Hejesoa, Raoelina Andriambololona, Nirina Gilbert Rasolofoson, Hanitriarivo Rakotoson, Jacqueline Rabesahala Raoelina Andriambololona, Lala Rarivomanantsoa, Naivo Rabesiranana

Fri Sep 23 2022 08:50:01 (1 day)

# 1.

The wave-particle duality is often considered as the modern and satisfactory answer that man found in searching to know the nature of light after more than 2000 years of questioning. It is also the answer given by quantum physics concerning the nature of matter particles and any other radiations. The aim of this work is to perform an analysis of this concept of wave-particle duality from a historical, philosophical and scientific point of view and to study and discuss about the relations which exist between it, the uncertainty principle and the concepts of phase space and microstates considered in statistical mechanics. These relations will be described and analyzed both from a physico-mathematical and historico-philosophical perspective. It is, in particular, highlighted that while the concepts of phase space and microstates were already introduced in classical physics long before the discovery of the wave-particle duality, a correct understanding of them cannot be achieved without quantum physics. But conversely, it is also shown that the relations of the wave-particle duality with uncertainty principle, phase space and microstates that are highlighted can help in a deeper understanding and more adequate description of this duality.

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Pravin Kumar Dahal, Ioannis Soranidis, Daniel R. Terno

Fri Sep 23 2022 08:49:59 (1 day)

# 2.

We describe the general features of formation and disappearance of regular spherically-symmetric black holes in semiclassical gravity. The allowed models are critically dependent on the requirement that the resulting object evolves in finite time according to a distant observer. Violation of the null energy condition is mandatory for this to happen, and we study the properties of the necessary energy-momentum tensor in the vicinity of the apparent horizon. In studies of the kinematics of massive test particles, it is found that the escape from a black hole is possible only on the ingoing trajectories when the particles are overtaken by the contracting outer apparent horizon. Tidal forces experienced by geodesic observers, infalling or escaping, are shown to be finite at the apparent horizon, although this is not true for non-geodesic trajectories.

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Axel Maas

Fri Sep 23 2022 08:49:53 (1 day)

# 3.

Physics in (canonical) quantum gravity needs to be manifestly diffeomorphism-invariant. Consequently, physical observables need to be formulated in terms of manifestly diffeomorphism-invariant operators, which are necessarily composite. This makes an evaluation in general involved, even if the concrete implementation of quantum gravity should be treatable (semi-)perturbatively in general. A mechanism developed by Fr\”ohlich, Morchio and Strocchi for flat-space-time quantum field theory may also be applicable in this case. It may be possible to test this mechanism with methods like dynamical triangulation.

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Alessandra Toncelli

Thu Sep 22 2022 08:00:00 (2 days)

# 4.

Nature Physics, Published online: 22 September 2022; doi:10.1038/s41567-022-01756-z

Laser light is usually limited to the same wavelength range as the spontaneous emission of the active material. A judicious choice of dielectric coatings on the cavity has now enabled laser emission far beyond the spectral range of the gain medium.

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Thu Sep 22 2022 06:53:53 (2 days)

# 5.

Coffey, Kevin (2022) (Competing?) Formulations of Newtonian Gravitation: Reflections at the Intersection of Interpretation, Methodology, and Equivalence. [Preprint]

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Thu Sep 22 2022 05:23:51 (2 days)

# 6.

McCoy, C.D. and Matarese, Vera (2022) When “Replicability” is More than Just “Reliability”: The Hubble Constant Controversy. [Preprint]

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physics.hist-ph updates on arXiv.org

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Marco Mamone-Capria

Wed Sep 21 2022 09:13:14 (3 days)

# 7.

F. Selleri’s main arguments for the restoration of absolute simultaneity in physics are analysed and shown to be faulty. In particular both the classical Sagnac effect and the recent so-called linear Sagnac effect can be dealt with within special relativity in a natural way. The appeal to the conventionality of simultaneity thesis is also shown to be ineffectual. Other arguments, such as the two spaceships’ argument and the block universe argument are briefly examined. Notwithstanding a negative overall assessment, the importance of keeping alive the research on the foundations of relativity is emphasized and Selleri’s role in this undertaking appreciated.

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physics.hist-ph updates on arXiv.org

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Galina Weinstein

Wed Sep 21 2022 09:13:13 (3 days)

# 8.

This paper discusses Maxwell’s demon thought experiment. In recent years, there has been extensive research on Maxwell’s demon. I first provide a detailed overview of important historical milestones of Maxwell’s demon thought experiment. Einstein would often write about both relativity and thermodynamics. In this paper, I first argue that: 1. Einstein spoke of Perpetuum mobile of the second kind (a Maxwell’s demon) in the context of the discovery of his relativity theory, the famous chasing a light beam thought experiment, and the contraction of lengths. 2. He would often compare relativity with thermodynamics. 3. When doing so, he would say that perpetual motion machines cannot exist. In the same category, no signal transmission faster than light is possible. 4. Einstein’s approach in speaking of the principles of thermodynamics and relativity suggests that he was occupied with “impossibility statements”. After discussing the essential aspects of Maxwell’s demon and the different ways of excorcising the demon, I examine the role of “impossibility statements” in Maxwell’s demon thought experiment.

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physics.hist-ph updates on arXiv.org

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Howard M. Wiseman, Eric G. Cavalcanti, Eleanor G. Rieffel

Tue Sep 20 2022 09:16:11 (4 days)

# 9.

A recent paper by two of us and co-workers, based on an extended Wigner’s friend scenario, demonstrated that certain empirical correlations predicted by quantum theory (QT) violate inequalities derived from a set of metaphysical assumptions we called “Local Friendliness” (LF). These assumptions are strictly weaker than those used for deriving Bell inequalities. Crucial to the theorem was the premise that a quantum system with reversible evolution could be an observer (colloquially, a “friend”). However, that paper was noncommittal on what would constitute an observer for the purpose of an experiment. Here, we present a new LF no-go theorem which takes seriously the idea that a system’s having thoughts is a sufficient condition for it to be an observer. Our new derivation of the LF inequalities uses four metaphysical assumptions, three of which are thought-related, including one that is explicitly called “Friendliness”. These four assumptions, in conjunction, imply LF for the type of friend that Friendliness commits one to accepting as an observer. In addition to these four metaphysical assumptions, this new no-go theorem requires two assumptions about what is technologically feasible: Human-Level Artificial Intelligence, and Universal Quantum Computing which is fast and large scale. The latter is often motivated by the belief that QT is universal, but this is not an assumption of the theorem. The intent of the new theorem is to give a clear goal for future experimentalists, and a clear motivation for trying to achieve that goal, by using carefully chosen and widely held assumptions. The popular stance that “quantum theory needs no interpretation” does not question any of our assumptions and so is ruled out by the theorem. Finally, we quantitatively discuss how difficult the experiment we envisage would be, and briefly discuss milestones on the paths towards it.

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David Bernal Neira

Tue Sep 20 2022 08:00:00 (4 days)

# 10.

Nature Physics, Published online: 20 September 2022; doi:10.1038/s41567-022-01772-z

Using a quantum annealer to simulate the dynamics of phase transitions shows that superconducting quantum devices can coherently evolve systems of thousands of individual elements. This is an important step toward quantum simulation and optimization.

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Tue Sep 20 2022 05:57:04 (4 days)

# 11.

Salimkhani, Kian and Rolffs, Matthias (2022) On Progress in Metaphysics. [Preprint]

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Tue Sep 20 2022 05:55:27 (4 days)

# 12.

Norton, John D. (2022) Lotteries, Bookmaking and Ancient Randomizers: Local and Global Analyses of Chance. [Preprint]

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Mehedi Hasan, Chetan Sriram Madasu, Ketan D. Rathod, Chang Chi Kwong, Christian Miniatura, Frédéric Chevy, and David Wilkowski

Mon Sep 19 2022 18:00:00 (4 days)

# 13.

Author(s): Mehedi Hasan, Chetan Sriram Madasu, Ketan D. Rathod, Chang Chi Kwong, Christian Miniatura, Frédéric Chevy, and David Wilkowski

Researchers produce analogues of hard-to-study quantum phenomena in a gas of strontium atoms near absolute zero.

[Phys. Rev. Lett. 129, 130402] Published Mon Sep 19, 2022

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Christoffer Hindlycke and Jan-Åke Larsson

Mon Sep 19 2022 18:00:00 (4 days)

# 14.

Author(s): Christoffer Hindlycke and Jan-Åke Larsson

The most well-known tool for studying contextuality in quantum computation is the n-qubit Stabilizer state tableau representation. We provide an extension that not only describes the quantum state but is also outcome deterministic. The extension enables a value assignment to exponentially many Pauli…

[Phys. Rev. Lett. 129, 130401] Published Mon Sep 19, 2022

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Mon Sep 19 2022 07:43:26 (5 days)

# 15.

Cuffaro, Michael E. (2022) Review of Slobodan Perović’s From Data to Quanta — Niels Bohr’s Vision of Physics. [Preprint]

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Mon Sep 19 2022 07:42:33 (5 days)

# 16.

Stoica, Ovidiu Cristinel (2022) Born rule from counting states. [Preprint]

**arXiv:2209.05549** (quant-ph)[Submitted on 12 Sep 2022]

Quantum Physics from Number Theory

The properties which give quantum mechanics its unique character – unitarity, complementarity, non-commutativity, uncertainty, nonlocality – derive from the algebraic structure of Hermitian operators acting on the wavefunction in complex Hilbert space. Because of this, the wavefunction cannot be shown to describe an ensemble of deterministic states where uncertainty simply reflects a lack of knowledge about which ensemble member describes reality. This has led to endless debates about the ontology of quantum mechanics. Here we derive these same quantum properties from number theoretic attributes of trigonometric functions applied to an explicitly ensemble-based representation of discretised complex Hilbert states. To avoid fine-tuning, the metric on state space must be p-adic rather than Euclidean where 1/p determines the fineness of the discretisation. This hints at both the existence of an underpinning fractal state-space geometry onto which states of the world are constrained. In this model, violation of Bell inequalities is a manifestation of this geometric constraint and does not imply a breakdown of local space-time causality. Because the discretised wavefunction describes an ensemble of states, there is no collapse of the wavefunction. Instead measurement describes a nonlinear clustering of state-space trajectories on the state-space geometry. In this model, systems with mass greater than the Planck mass will not exhibit quantum properties and instead behave classically. The geometric constraint suggests that the exponential increase in the size of state space with qubit number may break down with qubit numbers as small as a few hundred. Quantum mechanics is itself a singular limit of this number-theoretic model at p=∞. A modification of general relativity, consistent with this discretised model of quantum physics, is proposed.

]]>How to measure effect sizes for rational decision-making |

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Fri Sep 16 2022 11:06:39 (22 hours)

# 1.

Jäntgen, Ina (2022) How to measure effect sizes for rational decision-making. In: UNSPECIFIED.

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physics.hist-ph updates on arXiv.org

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Martin Korth

Fri Sep 16 2022 08:51:30 (1 day)

# 2.

The tremendous advances of research into artificial intelligence as well as neuroscience made over the last two to three decades have given further support to a renewed interest into philosophical discussions of the mind-body problem. Especially the last decade has seen a revival of panpsychist and idealist considerations, often focused on solving philosophical puzzles like the so-called hard problem of consciousness. While a number of respectable philosophers advocate some sort of panpsychistic solution to the mind-body problem now, fewer advocate that idealism can contribute substantially to the debate. Interest in idealism has nevertheless risen again, as can be seen also from recent overview articles and collections of works. The working hypothesis here is that a properly formulated idealism can not only provide an alternative view of the mind/matter gap, but that this new view will also shed light on open questions in our common scientific, i.e. materialist, world view. To investigate this possibility, idealism first of all needs a model for the integration of modern science which allows for a mathematically consistent reinterpretation of the physical world as a limiting case of a both material and non-material world, which would make the outcome of idealistic considerations accessible to scientific investigation. To develop such a model I will first try to explain what I mean when I speak of a ‘scientifically tenable’ idealism, including a formulation of the emanation problem which for idealism replaces the interaction problem, then give a very brief summary of the available elements of such a theory in the philosophical literature, before sketching out some ‘design questions’ which have to be answered upon the construction of such models, and finally put forward a first model for a scientifically tenable objective idealism.

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Eduardo Velasco-Aja, Jesus Anero

Fri Sep 16 2022 08:51:26 (1 day)

# 3.

In this master thesis, the Frobenius power series method is used to find spherically symmetric and static vacuum solutions to quadratic and cubic gravitational actions, representing quantum corrections to the Einstein-Hilbert action. After a motivation to the topic and an introduction, the power series solutions are presented. After recovering the results for the quadratic action of Stelle and collaborators, we found that when the Weyl cubic operator is present, the (2,2) family of solutions is still present while the Schwarzschid-de Sitter-like (1,-1) is not.

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Scott Aaronson

Fri Sep 16 2022 08:51:22 (1 day)

# 4.

I survey, for a general scientific audience, three decades of research into which sorts of problems admit exponential speedups via quantum computers — from the classics (like the algorithms of Simon and Shor), to the breakthrough of Yamakawa and Zhandry from April 2022. I discuss both the quantum circuit model, which is what we ultimately care about in practice but where our knowledge is radically incomplete, and the so-called oracle or black-box or query complexity model, where we’ve managed to achieve a much more thorough understanding that then informs our conjectures about the circuit model. I discuss the strengths and weaknesses of switching attention to sampling tasks, as was done in the recent quantum supremacy experiments. I make some skeptical remarks about widely-repeated claims of exponential quantum speedups for practical machine learning and optimization problems. Through many examples, I try to convey the “law of conservation of weirdness,” according to which every problem admitting an exponential quantum speedup must have some unusual property to allow the amplitude to be concentrated on the unknown right answer(s).

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Noncommutativity and logarithmic correction to the black hole entropy. (arXiv:2209.07168v1 [hep-th]) |

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Kumar S. Gupta, Tajron Jurić, Anđelo Samsarov, Ivica Smolić

Fri Sep 16 2022 08:51:16 (1 day)

# 5.

We study the noncommutative corrections to the entropy of the Reissner-Nordstr\”{o}m black hole using a $\kappa$-deformed scalar probe within the brick-wall framework. The noncommutativity is encoded in an Abelian Drinfeld twist constructed from the Killing vector fields of the Reissner-Nordstr\”{o}m black hole. We show that the noncommutative effects naturally lead to a logarithmic correction to the Bekenstein-Hawking entropy even at the lowest order of the WKB approximation. In contrast, such logarithmic corrections in the commutative setup appear only after the quantum effects are included through higher order WKB corrections or through higher loop effects. Our analysis thus provides further evidence towards the hypothesis that the noncommutative framework is capable of encoding quantum effects of gravity.

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M. Lagoin, C. Crauste-Thibierge, and A. Naert

Thu Sep 15 2022 18:00:00 (1 day)

# 6.

Author(s): M. Lagoin, C. Crauste-Thibierge, and A. Naert

We present an experimental realization at macroscopic scale of the storied Brownian ratchet, which is an illustration of the Maxwell’s demon. In our mechanism, the rotation of a centimeter-scale 1D Brownian object in a granular gas is detected by an electromechanical converter (dynamo), generating a…

[Phys. Rev. Lett. 129, 120606] Published Thu Sep 15, 2022

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Anurag Anshu; Aram W. Harrow; Mehdi Soleimanifar

Thu Sep 15 2022 08:00:00 (2 days)

# 7.

Nature Physics, Published online: 15 September 2022; doi:10.1038/s41567-022-01740-7

Entanglement entropy between two parts of a quantum state generally grows with volume, but for one-dimensional and some two-dimensional ground states, it scales with area. An area law has now been proven for a related metric in any dimension or geometry.

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Enrique Rico Ortega; Simone Montangero

Thu Sep 15 2022 08:00:00 (2 days)

# 8.

Nature Physics, Published online: 15 September 2022; doi:10.1038/s41567-022-01739-0

Limits on the quantum entanglement entropy in one dimension have been a key factor in understanding the physics of many-body systems. A bound that applies in any dimension has now been derived for a different measure known as entanglement spread.

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Thu Sep 15 2022 02:48:05 (2 days)

# 9.

Calderón, Francisco (2022) The Causal Axioms of Algebraic Quantum Field Theory: A Diagnostic. In: UNSPECIFIED.

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Thu Sep 15 2022 02:47:27 (2 days)

# 10.

Tappenden, Paul (2022) Pilot-Wave Theory without Nonlocality. [Preprint]

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Thu Sep 15 2022 02:46:13 (2 days)

# 11.

Kubiak, Adam P. (2022) Perspectival Realism and Frequentist Statistics: The Case of Jerzy Neyman’s Methodology and Philosophy. In: UNSPECIFIED.

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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David Schmid, Haoxing Du, John H. Selby, and Matthew F. Pusey

Wed Sep 14 2022 18:00:00 (2 days)

# 12.

Author(s): David Schmid, Haoxing Du, John H. Selby, and Matthew F. Pusey

We give a complete characterization of the (non)classicality of all stabilizer subtheories. First, we prove that there is a *unique* nonnegative and diagram-preserving quasiprobability representation of the stabilizer subtheory in all odd dimensions, namely Gross’s discrete Wigner function. This repre…

[Phys. Rev. Lett. 129, 120403] Published Wed Sep 14, 2022

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Anton L. Andersen and Klaus Mølmer

Wed Sep 14 2022 18:00:00 (2 days)

# 13.

Author(s): Anton L. Andersen and Klaus Mølmer

We present a protocol for probing the state of a quantum system by its resonant coupling and entanglement with a meter system. By continuous measurement of a time evolving meter observable, we infer the evolution of the entangled systems and, ultimately, the state and dynamics of the system of inter…

[Phys. Rev. Lett. 129, 120402] Published Wed Sep 14, 2022

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Wed Sep 14 2022 07:10:03 (3 days)

# 14.

Thebault, Karim P Y (2022) Big Bang Singularity Resolution In Quantum Cosmology. [Preprint]

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Jae Sung Lee, Sangyun Lee, Hyukjoon Kwon, and Hyunggyu Park

Tue Sep 13 2022 18:00:00 (3 days)

# 15.

Author(s): Jae Sung Lee, Sangyun Lee, Hyukjoon Kwon, and Hyunggyu Park

Landauer’s bound is the minimum thermodynamic cost for erasing one bit of information. As this bound is achievable only for quasistatic processes, finite-time operation incurs additional energetic costs. We find a tight finite-time Landauer’s bound by establishing a general form of the classical spe…

[Phys. Rev. Lett. 129, 120603] Published Tue Sep 13, 2022

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Nahuel Freitas and Massimiliano Esposito

Tue Sep 13 2022 18:00:00 (3 days)

# 16.

Author(s): Nahuel Freitas and Massimiliano Esposito

Maxwell’s demons work by rectifying thermal fluctuations. They are not expected to function at macroscopic scales where fluctuations become negligible and dynamics become deterministic. We propose an electronic implementation of an autonomous Maxwell’s demon that indeed stops working in the regular …

[Phys. Rev. Lett. 129, 120602] Published Tue Sep 13, 2022

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Felix Ahnefeld, Thomas Theurer, Dario Egloff, Juan Mauricio Matera, and Martin B. Plenio

Tue Sep 13 2022 18:00:00 (3 days)

# 17.

Author(s): Felix Ahnefeld, Thomas Theurer, Dario Egloff, Juan Mauricio Matera, and Martin B. Plenio

Shor’s factoring algorithm provides a superpolynomial speedup over all known classical factoring algorithms. Here, we address the question of which quantum properties fuel this advantage. We investigate a sequential variant of Shor’s algorithm with a fixed overall structure and identify the role of …

[Phys. Rev. Lett. 129, 120501] Published Tue Sep 13, 2022

**arXiv:2209.05344** (physics)[Submitted on 10 Jul 2022]

Order-of-magnitude test of a theory of the Mott problem

The Mott problem asks: Is there a microscopic physical mechanism – based (explicitly or implicitly) only on Schroedinger’s equation – that explains why a single alpha particle emitted in a single spherically symmetric s-wave nuclear decay produces a manifestly non-spherically-symmetric single track in a cloud chamber? This is a variant of the more general quantum measurement problem. Earlier, we proposed such a mechanism, drawing on quantum-mechanical Coulomb scattering and the thermal behavior of supersaturated vapors. Our analysis implied that, in a large enough sample, the probability that a track originates at distance R from the decay source is proportional to 1/R^2, with a proportionality constant which we expressed in terms of more fundamental parameters involving diverse physical processes, but were unable to estimate at the time. More recently, we tested the 1/R^2 law opportunistically using pedagogical cloud chamber video posted on the Internet. In the present paper, we draw on the chemical physics literature for an independent estimate of the proportionality constant. The estimate is rough, but within about 1.7 orders of magnitude (factor of 50) of a rough value that we derive directly from the video data. Given the crudeness of the experimental data, the roughness of the numerical estimates, and the extreme spread of concentrations involved (air molecules vs. subcritical vapor clusters of specific sizes), we view this level of agreement as significant, at this stage in the theory’s development.

]]>The paradox of infinitesimal granularity: Chaos and the reversibility of time in Newton’s theory of gravity. (arXiv:2209.03347v1 [nlin.CD]) |

from

by

Simon Portegies Zwart, Tjarda Boekholt

Sat Sep 10 2022 09:48:11 (1 hour)

# 1.

The fundamental laws of physics are time-symmetric, but our macroscopic experience contradicts this. The time reversibility paradox is partly a consequence of the unpredictability of Newton’s equations of motion. We measure the dependence of the fraction of irreversible, gravitational N-body systems on numerical precision and find that it scales as a power law. The stochastic wave packet reduction postulate then introduces fundamental uncertainties in the Cartesian phase space coordinates that propagate through classical three-body dynamics to macroscopic scales within the triple’s lifetime. The spontaneous collapse of the wave function then drives the global chaotic behavior of the Universe through the superposition of triple systems (and probably multi-body systems). The paradox of infinitesimal granularity then arises from the superposition principle, which states that any multi-body system is composed of an ensemble of three-body problems.

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Robert J. Scherrer

Sat Sep 10 2022 09:48:06 (1 hour)

# 2.

When the expansion of the universe is dominated by a perfect fluid with equation of state parameter $w$ and a sound speed $c_s$ satisfying $w = c_s^2 \le 1$, the Hubble parameter $H$ and time $t$ satisfy the bound $Ht \ge 1/3$. There has been recent interest in “ultra-slow” expansion laws with $Ht < 1/3$ (sometimes described as “fast expanding” models). We examine various models that can produce ultra-slow expansion: scalar fields with negative potentials, barotropic fluids, braneworld models, or a loitering phase in the early universe. Scalar field models and barotropic models for ultra-slow expansion are unstable to evolution toward $w = 1$ or $w \rightarrow \infty$ in the former case and $w \rightarrow \infty$ in the latter case. Braneworld models can yield ultra-slow expansion but require an expansion law beyond the standard Friedman equation. Loitering early universe models can produce a quasi-static expansion phase in the early universe but require an exotic negative-density component. These results suggest that appeals to an ultra-slow expansion phase in the early universe should be approached with some caution, although the loitering early universe may be worthy of further investigation. These results do not apply to ultra-slow contracting models.

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Chong-Sun Chu, Rong-Xin Miao

Sat Sep 10 2022 09:48:03 (1 hour)

# 3.

We propose that the quantum states of black hole responsible for the Bekenstein-Hawking entropy are given by a thin shell of Bell particles located at the region just underneath the horizon. We argue that the configuration can be stabilized by a new kind of degeneracy pressure which is suggested by noncommutative geometry. We utilize the work of Parikh and Wilczek to include the effect of tunneling on the Bell particles. We show that partially tunneled Bell particles give the Page curve for the Hawking radiation, and the entirety of information initially stored in the black hole is returned to the outside via the Hawking radiation. In view of entropic force, the location of these Bell states is naturally related to the island and the quantum extremal surface. Also, the thin shell of Bell particles may be interpreted as a firewall.

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physics.hist-ph updates on arXiv.org

by

Mani L. Bhaumik

Sat Sep 10 2022 09:44:32 (1 hour)

# 4.

Credible reasons are presented to reveal that many of the lingering century old enigmas, surrounding the behavior of at least an individual quantum particle, can be comprehended in terms of an objectively real specific wave function. This wave function is gleaned from the single particle energy-momentum eigenstate offered by the theory of space filling universal quantum fields that is an inevitable outcome of Dirac’s pioneering masterpiece. Examples of these well-known enigmas are wave particle duality, the de Broglie hypothesis, the uncertainty principle, wave function collapse, and predictions of measurement outcomes in terms of probability instead of certainty. Paul Dirac successfully incorporated special theory of relativity into quantum mechanics for the first time. This was accomplished through his ingenious use of matrices that allowed the equations of motion to maintain the necessary first order time derivative feature necessary for positive probability density. The ensuing Dirac equation for the electron led to the recognition of the mystifying quantized spin and magnetic moment as intrinsic properties in contrast to earlier ad hoc assumptions. The solution of his relativistic equation for the hydrogen atom produced results in perfect agreement with experimental data available at the time. The most far reaching prediction of the celebrated Dirac equation was the totally unexpected existence of anti-particles, culminating in the eventual development of the quantum field theory of the Standard Model that reveals the deepest secrets of the universe known to date.

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Olivia Y. Long, Kai Wang, Avik Dutt, Shanhui Fan

Sat Sep 10 2022 09:41:31 (1 hour)

# 5.

The duality of space and time in Maxwell’s equations has prompted interest in time boundaries and the accompanying temporal analog of spatial reflection and refraction. However, achieving observable time boundary effects at optical frequencies in real materials is challenging. In this work, we demonstrate that time reflection and refraction can be observed in a two-band model centered around a non-zero reference energy. Our model can be physically implemented in the synthetic frequency dimension as a system of two coupled dynamically-modulated ring resonators. We find that modulation at microwave frequencies is sufficient to observe time boundary effects for optical waves in synthetic frequency dimension. Our work shows that implementing multi-band models in synthetic dimensions opens a new avenue for further exploration of time boundaries.

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Sat Sep 10 2022 08:00:30 (3 hours)

# 6.

Castellani, Elena and Margoni, Emilia (2022) Renormalization Group Methods: Which Kind of Explanation? Studies in History and Philosophy of Science, 95. pp. 158-166.

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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J. Stevens, D. Szombati, M. Maffei, C. Elouard, R. Assouly, N. Cottet, R. Dassonneville, Q. Ficheux, S. Zeppetzauer, A. Bienfait, A. N. Jordan, A. Auffèves, and B. Huard

Fri Sep 09 2022 18:00:00 (17 hours)

# 7.

Author(s): J. Stevens, D. Szombati, M. Maffei, C. Elouard, R. Assouly, N. Cottet, R. Dassonneville, Q. Ficheux, S. Zeppetzauer, A. Bienfait, A. N. Jordan, A. Auffèves, and B. Huard

Qubits are physical, a quantum gate thus not only acts on the information carried by the qubit but also on its energy. What is then the corresponding flow of energy between the qubit and the controller that implements the gate? Here we exploit a superconducting platform to answer this question in th…

[Phys. Rev. Lett. 129, 110601] Published Fri Sep 09, 2022

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Thu Sep 08 2022 08:00:00 (2 days)

# 8.

Nature Physics, Published online: 08 September 2022; doi:10.1038/s41567-022-01766-x

It is easy to dismiss research into the foundations of quantum mechanics as irrelevant to physicists in other areas. Adopting this attitude misses opportunities to appreciate the richness of quantum mechanics.

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by

Karin Cedergren

Thu Sep 08 2022 08:00:00 (2 days)

# 9.

Nature Physics, Published online: 08 September 2022; doi:10.1038/s41567-022-01746-1

Although the ohm is ‘only’ a derived SI unit, the assumption that it plays an unobtrusive role could not be further from the truth, as Karin Cedergren reveals.

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Thu Sep 08 2022 05:08:47 (2 days)

# 10.

Franklin, Alexander and Robertson, Katie (2022) A Middle Way: A Non-Fundamental Approach to Many-Body Physics by Robert Batterman: Autonomy and Varieties of Reduction. [Preprint]

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Wed Sep 07 2022 02:10:48 (3 days)

# 11.

Ellerman, David (2022) Follow the Math!:The mathematics of quantum mechanics as the mathematics of set partitions linearized to (Hilbert) vector spaces. [Preprint]

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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V. Vilasini and Roger Colbeck

Tue Sep 06 2022 18:00:00 (3 days)

# 12.

Author(s): V. Vilasini and Roger Colbeck

Causality is fundamental to science, but it appears in several different forms. One is relativistic causality, which is tied to a spacetime structure and forbids signaling outside the future. A second is an operational notion of causation that considers the flow of information between physical syste…

[Phys. Rev. Lett. 129, 110401] Published Tue Sep 06, 2022

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Mon Sep 05 2022 05:40:21 (5 days)

# 13.

Vassallo, Antonio and Naranjo, Pedro and Koslowski, Tim (2022) A Proposal for a Metaphysics of Self-Subsisting Structures. I. Classical Physics. Synthese, 200. ISSN 1573-0964

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Sun Sep 04 2022 07:14:49 (6 days)

# 14.

Manchak, JB and Barrett, Thomas William (2022) A Hierarchy of Spacetime Symmetries: Holes to Heraclitus. [Preprint]

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Sat Sep 03 2022 04:43:21 (1 week)

# 15.

Hubert, Mario (2022) Review of Alyssa Ney’s The World in the Wave Function: A Metaphysics for Quantum Physics. [Preprint]

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Thu Sep 01 2022 15:28:24 (1 week)

# 16.

Gao, Shan (2022) Can Bohmian brains make minds? On shadows, puppets and zombies. [Preprint]

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Hippolyte Dourdent, Alastair A. Abbott, Nicolas Brunner, Ivan Šupić, and Cyril Branciard

Wed Aug 24 2022 18:00:00 (2 weeks)

# 17.

Author(s): Hippolyte Dourdent, Alastair A. Abbott, Nicolas Brunner, Ivan Šupić, and Cyril Branciard

While the standard formulation of quantum theory assumes a fixed background causal structure, one can relax this assumption within the so-called process matrix framework. Remarkably, some processes, termed causally nonseparable, are incompatible with a definite causal order. We explore a form of cer…

[Phys. Rev. Lett. 129, 090402] Published Wed Aug 24, 2022

]]>The paradox of infinitesimal granularity: Chaos and the reversibility of time in Newton’s theory of gravity. (arXiv:2209.03347v1 [nlin.CD]) |

from

by

Simon Portegies Zwart, Tjarda Boekholt

Sat Sep 10 2022 09:48:11 (1 hour)

# 1.

The fundamental laws of physics are time-symmetric, but our macroscopic experience contradicts this. The time reversibility paradox is partly a consequence of the unpredictability of Newton’s equations of motion. We measure the dependence of the fraction of irreversible, gravitational N-body systems on numerical precision and find that it scales as a power law. The stochastic wave packet reduction postulate then introduces fundamental uncertainties in the Cartesian phase space coordinates that propagate through classical three-body dynamics to macroscopic scales within the triple’s lifetime. The spontaneous collapse of the wave function then drives the global chaotic behavior of the Universe through the superposition of triple systems (and probably multi-body systems). The paradox of infinitesimal granularity then arises from the superposition principle, which states that any multi-body system is composed of an ensemble of three-body problems.

Send To > Keep unreadDelete

from

by

Robert J. Scherrer

Sat Sep 10 2022 09:48:06 (1 hour)

# 2.

When the expansion of the universe is dominated by a perfect fluid with equation of state parameter $w$ and a sound speed $c_s$ satisfying $w = c_s^2 \le 1$, the Hubble parameter $H$ and time $t$ satisfy the bound $Ht \ge 1/3$. There has been recent interest in “ultra-slow” expansion laws with $Ht < 1/3$ (sometimes described as “fast expanding” models). We examine various models that can produce ultra-slow expansion: scalar fields with negative potentials, barotropic fluids, braneworld models, or a loitering phase in the early universe. Scalar field models and barotropic models for ultra-slow expansion are unstable to evolution toward $w = 1$ or $w \rightarrow \infty$ in the former case and $w \rightarrow \infty$ in the latter case. Braneworld models can yield ultra-slow expansion but require an expansion law beyond the standard Friedman equation. Loitering early universe models can produce a quasi-static expansion phase in the early universe but require an exotic negative-density component. These results suggest that appeals to an ultra-slow expansion phase in the early universe should be approached with some caution, although the loitering early universe may be worthy of further investigation. These results do not apply to ultra-slow contracting models.

Send To > Keep unreadDelete

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by

Chong-Sun Chu, Rong-Xin Miao

Sat Sep 10 2022 09:48:03 (1 hour)

# 3.

We propose that the quantum states of black hole responsible for the Bekenstein-Hawking entropy are given by a thin shell of Bell particles located at the region just underneath the horizon. We argue that the configuration can be stabilized by a new kind of degeneracy pressure which is suggested by noncommutative geometry. We utilize the work of Parikh and Wilczek to include the effect of tunneling on the Bell particles. We show that partially tunneled Bell particles give the Page curve for the Hawking radiation, and the entirety of information initially stored in the black hole is returned to the outside via the Hawking radiation. In view of entropic force, the location of these Bell states is naturally related to the island and the quantum extremal surface. Also, the thin shell of Bell particles may be interpreted as a firewall.

Send To > Keep unreadDelete

from

physics.hist-ph updates on arXiv.org

by

Mani L. Bhaumik

Sat Sep 10 2022 09:44:32 (1 hour)

# 4.

Credible reasons are presented to reveal that many of the lingering century old enigmas, surrounding the behavior of at least an individual quantum particle, can be comprehended in terms of an objectively real specific wave function. This wave function is gleaned from the single particle energy-momentum eigenstate offered by the theory of space filling universal quantum fields that is an inevitable outcome of Dirac’s pioneering masterpiece. Examples of these well-known enigmas are wave particle duality, the de Broglie hypothesis, the uncertainty principle, wave function collapse, and predictions of measurement outcomes in terms of probability instead of certainty. Paul Dirac successfully incorporated special theory of relativity into quantum mechanics for the first time. This was accomplished through his ingenious use of matrices that allowed the equations of motion to maintain the necessary first order time derivative feature necessary for positive probability density. The ensuing Dirac equation for the electron led to the recognition of the mystifying quantized spin and magnetic moment as intrinsic properties in contrast to earlier ad hoc assumptions. The solution of his relativistic equation for the hydrogen atom produced results in perfect agreement with experimental data available at the time. The most far reaching prediction of the celebrated Dirac equation was the totally unexpected existence of anti-particles, culminating in the eventual development of the quantum field theory of the Standard Model that reveals the deepest secrets of the universe known to date.

Send To > Keep unreadDelete

from

by

Olivia Y. Long, Kai Wang, Avik Dutt, Shanhui Fan

Sat Sep 10 2022 09:41:31 (1 hour)

# 5.

The duality of space and time in Maxwell’s equations has prompted interest in time boundaries and the accompanying temporal analog of spatial reflection and refraction. However, achieving observable time boundary effects at optical frequencies in real materials is challenging. In this work, we demonstrate that time reflection and refraction can be observed in a two-band model centered around a non-zero reference energy. Our model can be physically implemented in the synthetic frequency dimension as a system of two coupled dynamically-modulated ring resonators. We find that modulation at microwave frequencies is sufficient to observe time boundary effects for optical waves in synthetic frequency dimension. Our work shows that implementing multi-band models in synthetic dimensions opens a new avenue for further exploration of time boundaries.

Send To > Keep unreadDelete

from

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Sat Sep 10 2022 08:00:30 (3 hours)

# 6.

Castellani, Elena and Margoni, Emilia (2022) Renormalization Group Methods: Which Kind of Explanation? Studies in History and Philosophy of Science, 95. pp. 158-166.

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from

PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

by

J. Stevens, D. Szombati, M. Maffei, C. Elouard, R. Assouly, N. Cottet, R. Dassonneville, Q. Ficheux, S. Zeppetzauer, A. Bienfait, A. N. Jordan, A. Auffèves, and B. Huard

Fri Sep 09 2022 18:00:00 (17 hours)

# 7.

Author(s): J. Stevens, D. Szombati, M. Maffei, C. Elouard, R. Assouly, N. Cottet, R. Dassonneville, Q. Ficheux, S. Zeppetzauer, A. Bienfait, A. N. Jordan, A. Auffèves, and B. Huard

Qubits are physical, a quantum gate thus not only acts on the information carried by the qubit but also on its energy. What is then the corresponding flow of energy between the qubit and the controller that implements the gate? Here we exploit a superconducting platform to answer this question in th…

[Phys. Rev. Lett. 129, 110601] Published Fri Sep 09, 2022

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Thu Sep 08 2022 08:00:00 (2 days)

# 8.

Nature Physics, Published online: 08 September 2022; doi:10.1038/s41567-022-01766-x

It is easy to dismiss research into the foundations of quantum mechanics as irrelevant to physicists in other areas. Adopting this attitude misses opportunities to appreciate the richness of quantum mechanics.

Send To > Keep unreadDelete

from

by

Karin Cedergren

Thu Sep 08 2022 08:00:00 (2 days)

# 9.

Nature Physics, Published online: 08 September 2022; doi:10.1038/s41567-022-01746-1

Although the ohm is ‘only’ a derived SI unit, the assumption that it plays an unobtrusive role could not be further from the truth, as Karin Cedergren reveals.

Send To > Keep unreadDelete

from

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Thu Sep 08 2022 05:08:47 (2 days)

# 10.

Franklin, Alexander and Robertson, Katie (2022) A Middle Way: A Non-Fundamental Approach to Many-Body Physics by Robert Batterman: Autonomy and Varieties of Reduction. [Preprint]

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Wed Sep 07 2022 02:10:48 (3 days)

# 11.

Ellerman, David (2022) Follow the Math!:The mathematics of quantum mechanics as the mathematics of set partitions linearized to (Hilbert) vector spaces. [Preprint]

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

by

V. Vilasini and Roger Colbeck

Tue Sep 06 2022 18:00:00 (3 days)

# 12.

Author(s): V. Vilasini and Roger Colbeck

Causality is fundamental to science, but it appears in several different forms. One is relativistic causality, which is tied to a spacetime structure and forbids signaling outside the future. A second is an operational notion of causation that considers the flow of information between physical syste…

[Phys. Rev. Lett. 129, 110401] Published Tue Sep 06, 2022

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Mon Sep 05 2022 05:40:21 (5 days)

# 13.

Vassallo, Antonio and Naranjo, Pedro and Koslowski, Tim (2022) A Proposal for a Metaphysics of Self-Subsisting Structures. I. Classical Physics. Synthese, 200. ISSN 1573-0964

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Sun Sep 04 2022 07:14:49 (6 days)

# 14.

Manchak, JB and Barrett, Thomas William (2022) A Hierarchy of Spacetime Symmetries: Holes to Heraclitus. [Preprint]

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Sat Sep 03 2022 04:43:21 (1 week)

# 15.

Hubert, Mario (2022) Review of Alyssa Ney’s The World in the Wave Function: A Metaphysics for Quantum Physics. [Preprint]

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Thu Sep 01 2022 15:28:24 (1 week)

# 16.

Gao, Shan (2022) Can Bohmian brains make minds? On shadows, puppets and zombies. [Preprint]

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Hippolyte Dourdent, Alastair A. Abbott, Nicolas Brunner, Ivan Šupić, and Cyril Branciard

Wed Aug 24 2022 18:00:00 (2 weeks)

# 17.

Author(s): Hippolyte Dourdent, Alastair A. Abbott, Nicolas Brunner, Ivan Šupić, and Cyril Branciard

While the standard formulation of quantum theory assumes a fixed background causal structure, one can relax this assumption within the so-called process matrix framework. Remarkably, some processes, termed causally nonseparable, are incompatible with a definite causal order. We explore a form of cer…

[Phys. Rev. Lett. 129, 090402] Published Wed Aug 24, 2022

]]>上午10:02 | | | Isaac Layton, Jonathan Oppenheim, Zachary Weller-Davies | | | quant-ph updates on arXiv.org |

We study the back-reaction of quantum systems onto classical ones. Taking the starting point that semi-classical physics should be described at all times by a point in classical phase space and a quantum state in Hilbert space, we consider an unravelling approach, describing the system in terms of a classical-quantum trajectory. We derive the general form of the dynamics under the assumptions that the classical trajectories are continuous and the evolution is autonomous, and the requirement that the dynamics is linear and completely positive in the combined classical-quantum state. This requirement is necessary in order to consistently describe probabilities, and forces the dynamics to be stochastic when the back-reaction is non-zero. The resulting equations of motion are natural generalisations of the standard semi-classical equations of motion, but since the resulting dynamics is linear in the combined classical-quantum state, it does not lead to the pathologies which usually follow from evolution laws based on expectation values. In particular, the evolution laws we present account for correlations between the classical and quantum system, which resolves issues associated with other semi-classical approaches. In addition, despite a breakdown of predictability in the classical degrees of freedom, the quantum state evolves deterministically conditioned on the classical trajectory, provided a trade-off between decoherence and diffusion is saturated. As a result, the quantum state remains pure when conditioned on the classical trajectory. To illustrate these points, we numerically simulate a number of semi-classical toy models, including one of vacuum fluctuations as a source driving the expansion of the universe. Finally, we discuss the application of these results to semi-classical gravity, and the black-hole information problem.

Quantum superpositions of Minkowski spacetime. (arXiv:2208.12083v1 [gr-qc])

上午10:02 | | | Joshua Foo, Cemile Senem Arabaci, Magdalena Zych, Robert B. Mann | | | quant-ph updates on arXiv.org |

Within any anticipated unifying theory of quantum gravity, it should be meaningful to combine the fundamental notions of quantum superposition and spacetime to obtain so-called “spacetime superpositions”: that is, quantum superpositions of different spacetimes not related by a global coordinate transformation. Here we consider the quantum-gravitational effects produced by superpositions of periodically identified Minkowski spacetime (i.e.\ Minkowski spacetime with a periodic boundary condition) with different characteristic lengths. By coupling relativistic quantum matter to fields on such a spacetime background (which we model using the Unruh-deWitt particle detector model), we are able to show how one can in-principle “measure” the field-theoretic effects produced by such a spacetime. We show that the detector’s response exhibits discontinuous resonances at rational ratios of the superposed periodic length scale.

上午10:02 | | | Sabre Kais | | | quant-ph updates on arXiv.org |

Classical phase transitions, like solid-liquid-gas or order-disorder spin magnetic phases, are all driven by thermal energy fluctuations by varying the temperature. On the other hand, quantum phase transitions happen at absolute zero temperature with quantum fluctuations causing the ground state energy to show abrupt changes as one varies the system parameters like electron density, pressure, disorder, or external magnetic field. Phase transitions happen at critical values of the controlling parameters, such as the critical temperature in classical phase transitions, and system critical parameters in the quantum case. However, true criticality happens only at the thermodynamic limit, when the number of particles goes to infinity with constant density. To perform the calculations for the critical parameters, finite size scaling approach was developed to extrapolate information from a finite system to the thermodynamic limit. With the advancement in the experimental and theoretical work in the field of ultra-cold systems, particularly trapping and controlling single atomic and molecular systems, one can ask: do finite systems exhibit quantum phase transition? To address this question, finite size scaling for finite system was developed to calculate the quantum critical parameters. Recent observation of a quantum phase transition in a single trapped 171 Yb ion in the Paul trap indicates the possibility of quantum phase transition in finite systems. This perspective focuses on examining chemical processes at ultracold temperature as quantum phase transitions, particularly the formation and dissociation of chemical bonds, which is the basic process for understanding the whole of chemistry

Testing Quantum Mechanics using Noisy Quantum Computers. (arXiv:2108.02201v4 [quant-ph] UPDATED)

上午10:02 | | | Kevin Slagle | | | quant-ph updates on arXiv.org |

We outline a proposal to test quantum mechanics in the high-complexity regime using noisy intermediate-scale quantum (NISQ) devices. The procedure involves simulating a non-Clifford random circuit, followed by its inverse, and then checking that the resulting state is the same as the initial state. We are motivated by the hypothesis that quantum mechanics is not fundamental, but instead emerges from a theory with less computational power, such as classical mechanics. This emergent quantum mechanics (EmQM) hypothesis makes the prediction that quantum computers will not be capable of sufficiently complex quantum computations. We show that quantum mechanics predicts that the fidelity of our procedure decays exponentially with circuit depth (due to noise in NISQ devices), while EmQM predicts that the fidelity will decay significantly more rapidly for sufficiently deep circuits, which is the experimental signature that we propose to search for. We estimate rough bounds for when possible signals of EmQM should be expected. Furthermore, we find that highly informative experiments should require only thousands qubits.

上午10:02 | | | physics.hist-ph updates on arXiv.org |

Authors: Martin Korth

The tremendous advances of research into artificial intelligence as well as neuroscience made over the last two to three decades have given further support to a renewed interest into philosophical discussions of the mind-body problem. Especially the last decade has seen a revival of panpsychist and idealist considerations, often focused on solving philosophical puzzles like the so-called hard problem of consciousness. While a number of respectable philosophers advocate some sort of panpsychistic solution to the mind-body problem now, fewer advocate that idealism can contribute substantially to the debate. Interest in idealism has nevertheless risen again, as can be seen also from recent overview articles and collections of works. The working hypothesis here is that a properly formulated idealism can not only provide an alternative view of the mind/matter gap, but that this new view will also shed light on open questions in our common scientific, i.e. materialist, world view. To investigate this possibility, idealism first of all needs a model for the integration of modern science which allows for a mathematically consistent reinterpretation of the physical world as a limiting case of a both material and non-material world, which would make the outcome of idealistic considerations accessible to scientific investigation. To develop such a model I will first try to explain what I mean when I speak of a ‘scientifically tenable’ idealism, including a formulation of the emanation problem which for idealism replaces the interaction problem, then give a very brief summary of the available elements of such a theory in the philosophical literature, before sketching out some ‘design questions’ which have to be answered upon the construction of such models, and finally put forward a first model for a scientifically tenable objective idealism.

Quantum Gravitational Decoherence in the 3 Neutrino Flavor Scheme. (arXiv:2208.11754v1 [hep-ph])

上午10:02 | | | gr-qc updates on arXiv.org |

Authors: Dominik Hellmann, Heinrich Päs, Erika Rani

In many theories of quantum gravity quantum fluctuations of spacetime may serve as an environment for decoherence. Here we study quantum-gravitational decoherence of high energy astrophysical neutrinos in the presence of fermionic dark sectors and for a realistic three neutrino scenario. We show how violation of global symmetries expected to arise in quantum gravitational interactions provides a possibility to pin down the number of dark matter fermions in the universe. Furthermore, we predict the expected total neutrino flux and flavor ratios at experiments depending on the flavor composition at the source.

Neutrino Decoherence from Generalised Uncertainty. (arXiv:2208.12062v1 [hep-ph])

上午10:02 | | | gr-qc updates on arXiv.org |

Authors: Indra Kumar Banerjee, Ujjal Kumar Dey

Quantum gravity models predict a minimal measurable length which gives rise to a modification in the uncertainty principle. One of the simplest manifestations of these generalised uncertainty principles is the linear quadratic generalised uncertainty principle which leads to a modified Heisenberg algebra. This can alter the usual von-Neumann evolution of density matrix to a Lindblad-type equation. We show how this can give rise to decoherence in neutrino propagation in vacuum. The decoherence effects due to the linear quadratic generalised uncertainty principle are extremely minimal and are unlikely to be detectable in the existing or upcoming experimental facilities for any of the natural sources of neutrinos. We also show that, in principle, there can be other variants of generalised uncertainty principle which predict verifiable decoherence effects for the cosmic neutrino background.

How (and Why) to Think that the Brain is Literally a Computer

2022年8月25日 星期四 下午1:57 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Maley, Corey J. (2022) How (and Why) to Think that the Brain is Literally a Computer. [Preprint]

Experiments with levitated force sensor challenge theories of dark energy

2022年8月25日 星期四 上午8:00 | | | Jiangfeng Du | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 25 August 2022; doi:10.1038/s41567-022-01706-9

In experiments with a levitated force sensor, no signatures of a fifth force are detected. This rules out the basic chameleon model, which is a popular theory providing an explanation for dark energy.

Ehrenfest Theorems, Deformation Quantization, and the Geometry of Inter-Model Reduction

2022年8月25日 星期四 上午12:55 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Rosaler, Joshua (2018) Ehrenfest Theorems, Deformation Quantization, and the Geometry of Inter-Model Reduction. Generalized Ehrenfest Relations, Deformation Quantization, and the Geometry of Inter-Model Reduction.

Do quantum observers have minds?

2022年8月25日 星期四 上午12:50 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2022) Do quantum observers have minds? [Preprint]

Superdeterminism: a reappraisal

2022年8月24日 星期三 上午8:00 | | | Latest Results for Synthese |

**Abstract**

This paper addresses a particular interpretation of quantum mechanics, i.e. superdeterminism. In short, superdeterminism i) takes the world to be fundamentally deterministic, ii) postulates hidden variables, and iii) contra Bell, saves locality at the cost of violating the principle of statistical independence. Superdeterminism currently enjoys little support in the physics and philosophy communities. Many take it to posit the ubiquitous occurrence of hard-to-digest conspiratorial and coincidental events; others object that violating the principle of statistical independence implies the death of the scientific methodology. In this paper, we offer a defense to these and other objections. To counter the conspiracy objection, we draw upon the philosophical literature on time travel, and conclude that the picture of the world offered by the superdeterminist does not need to be particularly surprising or conspiratorial. We then move on to other recent objections, in particular those that focus on the methodology of science and the nature of the physical laws compatible with superdeterminism. A key ingredient of our arguments is that the principle of statistical independence may be violated *in theory*, but valid *for practical purposes*. Our overarching goal is to offer a defense of superdeterminism with respect to its main objections, so that it can earn its keep as a legitimate contender among the possible interpretations of quantum mechanics.

Empty space and the (positive) cosmological constant

2022年8月20日 星期六 下午11:06 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Schneider, Mike D. (2022) Empty space and the (positive) cosmological constant. [Preprint]

]]>上午10:36 | | | physics.hist-ph updates on arXiv.org |

Authors: C. Romero

In 1918, H. Weyl proposed a unified theory of gravity and electromagnetism based on a generalization of Riemannian geometry. With hindsight we now could say that the theory carried with it some of the most original ideas that inspired the physics of the twentieth century. In a book published in 1927, Bertrand Russell devoted an entire chapter to explain and give a critical appraisal of Weyl’s theory. We briefly revisit the text written by Russell, who gave one of the first philosophical approaches to Weyl’s ideas.

Quantum Mechanics in Phase Space: An introduction. (arXiv:2208.08682v1 [quant-ph])

上午10:36 | | | Eduardo Martín-Martínez | | | quant-ph updates on arXiv.org |

Collection of lecture notes introducing quantum mechanics in phase space and basic Gaussian quantum mechanics.

Early heart disease prediction using hybrid quantum classification. (arXiv:2208.08882v1 [quant-ph])

上午10:36 | | | Hanif Heidari, Gerhard Hellstern | | | quant-ph updates on arXiv.org |

The rate of heart morbidity and heart mortality increases significantly which affect the global public health and world economy. Early prediction of heart disease is crucial for reducing heart morbidity and mortality. This paper proposes two quantum machine learning methods i.e. hybrid quantum neural network and hybrid random forest quantum neural network for early detection of heart disease. The methods are applied on the Cleveland and Statlog datasets. The results show that hybrid quantum neural network and hybrid random forest quantum neural network are suitable for high dimensional and low dimensional problems respectively. The hybrid quantum neural network is sensitive to outlier data while hybrid random forest is robust on outlier data. A comparison between different machine learning methods shows that the proposed quantum methods are more appropriate for early heart disease prediction where 96.43% and 97.78% area under curve are obtained for Cleveland and Statlog dataset respectively.

Bell test in a classical pilot-wave system. (arXiv:2208.08940v1 [physics.flu-dyn])

上午10:36 | | | Konstantinos Papatryfonos, Louis Vervoort, André Nachbin, Matthieu Labousse, John W M Bush | | | quant-ph updates on arXiv.org |

Since its discovery in 2005, the hydrodynamic pilot-wave system has provided a concrete macroscopic realization of wave-particle duality and concomitant classical analogs of many quantum effects. The question naturally arises as to whether this hydrodynamic pilot-wave system might provide a platform for violating Bell’s inequality, and so yield a classical analog of quantum entanglement. We here present the results of a static Bell test performed with a numerical model of the hydrodynamic pilot-wave system, specifically a coupled bipartite tunneling system. We demonstrate that, under certain conditions, the Bell inequality is violated owing to the wave-mediated coupling between the two subsystems. Our system represents a new platform for exploring whether Bell’s Theorem, typically taken to be a no-go theorem for all local hidden variable theories, need be respected by the class of hidden variable theories based on non-Markovian pilot-wave dynamics.

上午10:36 | | | Indrajit Sen | | | quant-ph updates on arXiv.org |

Non-normalizable states are difficult to interpret in orthodox quantum mechanics and usually discarded as mathematical artifacts. We argue that pilot-wave theory gives a straightforward physical interpretation of non-normalizable quantum states, as the theory requires only a normalized density of configurations to generate statistical predictions. In order to better understand such states, we conduct the first study of non-normalizable solutions of the harmonic oscillator from a pilot-wave perspective. We show that, contrary to intuitions from orthodox quantum mechanics, the non-normalizable eigenstates and their superpositions are bound states in the sense that the velocity field $v_y \to 0$ at large $\pm y$. We argue that defining a physically meaningful equilibrium density for such states requires a new notion of equilibrium, named pilot-wave equilibrium, which is a generalisation of the notion of quantum equilibrium. We define a new $H$-function $H_{pw}$, and prove that a density in pilot-wave equilibrium minimises $H_{pw}$, is equivariant, and remains in equilibrium with time. We prove, via an $H$-theorem for $H_{pw}$, that an arbitrary initial density relaxes to pilot-wave equilibrium density at a coarse-grained level, under assumptions similar to those for relaxation to quantum equilibrium. Using the relationship between the two notions of equilibrium and the asymptotic nature of the velocity field, we show how existing numerical simulations on quantum equilibrium can be utilised to study relaxation to pilot-wave equilibrium. Lastly, we outline an experimental proposal to detect continuous-energy eigenstates, discuss applications in quantum field theory and quantum gravity, and discuss implications for pilot-wave theory and quantum foundations in general.

Resource theory of causal connection. (arXiv:2110.03233v2 [quant-ph] UPDATED)

上午10:36 | | | Simon Milz, Jessica Bavaresco, Giulio Chiribella | | | quant-ph updates on arXiv.org |

The capacity of distant parties to send signals to one another is a fundamental requirement in many information-processing tasks. Such ability is determined by the causal structure connecting the parties, and more generally, by the intermediate processes carrying signals from one laboratory to another. Here we build a fully fledged resource theory of causal connection for all multi-party communication scenarios, encompassing those where the parties operate in a definite causal order and also where the order is indefinite. We define and characterize the set of free processes and three different sets of free transformations thereof, resulting in three distinct resource theories of causal connection. In the causally ordered setting, we identify the most resourceful processes in the bipartite and tripartite scenarios. In the general setting, instead, our results suggest that there is no global most valuable resource. We establish the signalling robustness as a resource monotone of causal connection and provide tight bounds on it for many pertinent sets of processes. Finally, we introduce a resource theory of causal non-separability, and show that it is — in contrast to the case of causal connection — unique. Together our results offer a flexible and comprehensive framework to quantify and transform general quantum processes, as well as insights into their multi-layered causal connection structures.

Computing spacetime. (arXiv:2205.05705v2 [hep-th] UPDATED)

上午10:36 | | | Juan F. Pedraza, Andrea Russo, Andrew Svesko, Zachary Weller-Davies | | | quant-ph updates on arXiv.org |

Inspired by the universality of computation, we advocate for a principle of spacetime complexity, where gravity arises as a consequence of spacetime optimizing the computational cost of its own quantum dynamics. This principle is explicitly realized in the context of the Anti-de Sitter/Conformal Field Theory correspondence, where complexity is naturally understood in terms of state preparation via Euclidean path integrals, and Einstein’s equations emerge from the laws of quantum complexity. We visualize spacetime complexity using Lorentzian threads which, conceptually, represent the operations needed to prepare a quantum state in a tensor network discretizing spacetime. Thus, spacetime itself evolves via optimized computation.

上午10:36 | | | gr-qc updates on arXiv.org |

Authors: Manosh T. Manoharan, N. Shaji, Titus K. Mathew

This article investigates the relationship between the holographic principle and the laws of thermodynamics in explaining the late-time acceleration of the universe. First, we explore the possibilities of generating the standard holographic dark energy (SHDE) from the laws of horizon thermodynamics. Except for entropies that follow an exponent stretched area law, unless we redefine the horizon temperature, we found it challenging to construct a one-to-one correspondence between the dark energies defined by the holographic principle and the laws of thermodynamics. Secondly, in SHDE models, unless we invoke some phenomenological interactions, it is impossible to explain the late-time cosmic acceleration with the Hubble horizon as the IR cutoff. On the other hand, it is possible to induce dark energy as an integration constant using the laws of thermodynamics on the Hubble horizon. These motivated us to explore a feasible way to invoke the holographic principle from the laws of horizon thermodynamics. We show that the additional terms that appear in the modified Friedmann equations on using entropies other than the Bekenstein-Hawking entropy in the first law of thermodynamics can behave like a dynamic holographic dark energy (HDE). We study the features of such an HDE with R\’enyi entropy as the choice without considering any non-standard interactions. Interestingly, the resulting form of dark energy reduces to the standard cosmological constant when R\’enyi entropy reduces to the Bekenstein-Hawking entropy. By examining different parameters, we affirm the validity of our approach to dark energy, which respects both holographic principle and thermodynamics.

GUP-corrected $\Lambda$CDM cosmology. (arXiv:2208.08830v1 [gr-qc])

上午10:36 | | | gr-qc updates on arXiv.org |

Authors: Salih Kibaroğlu

In this study, we investigate the effect of the generalized uncertainty principle on the $\Lambda$CDM cosmological model. Using quantum corrected Unruh effect and Verlinde’s entropic gravity idea, we find Planck-scale corrected Friedmann equations with a cosmological constant. These results modify the $\Lambda$CDM cosmology.

Old Ideas for New Physicists:1. (arXiv:2208.08959v1 [hep-th])

上午10:36 | | | gr-qc updates on arXiv.org |

Authors: T. Banks

We review and clarify ideas proposed many years ago for understanding cosmology in a holographic framework. The basic strategy is to use Jacobson’s\cite{ted95} identification of Einstein’s equations with the hydrodynamic equations of the “Area = 4 Entropy” law for causal diamonds, to identify a quantum system whose hydrodynamics match those of a given space-time. This can be done exactly for a system with any positive cosmological constant, which saturates the entropy bound for all times. The quantum system is a sequence of (cut-off) $1+1$ dimensional CFTs, with central charge proportional to the entropy in causal diamonds along an FRW geodesic. This matches with a recent\cite{BZ} proposal that the modular Hamiltonian of any causal diamond for non-negative c.c. is the $L_0$ generator of such a CFT. When an early de Sitter era is followed by slow roll expansion of the horizon, disjoint horizon volumes (which are gauge copies in an eternal dS space, but become physical due to slow roll expansion of the horizon area) manifest as a dilute gas of black holes in a post-inflationary era. Entropy fluctuations of individual black holes manifest as CMB fluctuations, and the tensor/scalar ratio is suppressed by an extra factor of the slow roll parameter $\epsilon$. Black hole evaporation provides the Hot Big Bang and baryogenesis. Black hole mergers can easily provide a source of primordial BH dark matter that dominates radiation at a temperature of $1$ eV, but numerical simulations are required to determine whether the model can explain the actual dark matter in our universe.

Can pragmatist quantum realism explain protective measurements?

2022年8月17日 星期三 下午3:31 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2022) Can pragmatist quantum realism explain protective measurements? [Preprint]

Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator

2022年8月16日 星期二 下午6:00 | | | I. J. Arnquist et al. (Majorana Collaboration) | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): I. J. Arnquist *et al.* (Majorana Collaboration)

The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in Ge76) array of p-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard …

[Phys. Rev. Lett. 129, 080401] Published Tue Aug 16, 2022

MOND and meta-empirical theory assessment

2022年8月16日 星期二 上午8:00 | | | Latest Results for Synthese |

**Abstract**

While \(\Lambda \) CDM has emerged as the standard model of cosmology, a small group of physicists defends modified newtonian dynamics (MOND) as an alternative view on cosmology. Exponents of MOND have employed a broad, at times explicitly philosophical, conceptual perspective in arguing their case. This paper offers reasons why that MONDian defense has been ineffective. First, we argue that the defense is ineffective according to Popperian or Lakatosian views–ostensibly the preferred philosophical views on theory assessment of proponents of MOND. Second, we argue that the defense of MOND can instead best be reconstructed as an instance of meta-empirical theory assessment. The formal employment of meta-empirical assessment by MONDians is unconvincing, however, because it lacks a sufficient epistemic foundation. Specifically, the MONDian No Alternatives Argument relies on falsifiability or explanation conditions that lack epistemic relevance, while the argument from Unexpected Explanatory Success fails since there is a known alternative to MOND. In the last part of the paper, we draw some lessons for applications of meta-empirical assessment more generally.

Cantor diagonal argument for real numbers

2022年8月16日 星期二 上午12:44 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hudson, Richard (2022) Cantor diagonal argument for real numbers. [Preprint]

Direct observation of relativistic broken plasma waves

2022年8月15日 星期一 上午8:00 | | | Victor Malka | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 15 August 2022; doi:10.1038/s41567-022-01717-6

In a plasma-based accelerator, the amplitude of the plasma wave is constrained by the wavebreaking limit. Experiments reveal features of the plasma waves at the point at which wavebreaking occurs.

2022年8月14日 星期日 下午2:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Kastner, Ruth (2022) Physical Time as Human Time. [Preprint]

2022年8月14日 星期日 下午2:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Adlam, Emily and Linnemann, Niels and Read, James (2022) Constructive Axiomatics in Spacetime Physics Part III: A Constructive Axiomatic Approach to Quantum Spacetime. [Preprint]

]]>上午9:40 | | | physics.hist-ph updates on arXiv.org |

Authors: J. Brian Pitts

The questions of what represents space-time in GR, the status of gravitational energy, the substantivalist-relationalist issue, and the (non)exceptional status of gravity are interrelated. If space-time has energy-momentum, then space-time is substantival. Two extant ways to avoid the substantivalist conclusion deny that the energy-bearing metric is part of space-time or deny that gravitational energy exists. Feynman linked doubts about gravitational energy to GR-exceptionalism; particle physics egalitarianism encourages realism about gravitational energy.

This essay proposes a third view, involving a particle physics-inspired non-perturbative split that characterizes space-time with a constant background _matrix_ (not a metric), avoiding the inference from gravitational energy to substantivalism: space-time is (M, eta), where eta=diag(-1,1,1,1) is a spatio-temporally constant numerical signature matrix (already used in GR with spinors). The gravitational potential, bearing any gravitational energy, is g_(munu)(x)-eta (up to field redefinitions), an _affine_ geometric object with a tensorial Lie derivative and a vanishing covariant derivative. This non-perturbative split permits strong fields, arbitrary coordinates, and arbitrary topology, and hence is pure GR by almost any standard. This razor-thin background, unlike more familiar ones, involves no extra gauge freedom and so lacks their obscurities and carpet lump-moving.

After a discussion of Curiel’s GR exceptionalist rejection of energy conservation, the two traditional objections to pseudotensors, coordinate dependence and nonuniqueness, are explored. Both objections are inconclusive and getting weaker. A literal interpretation of Noether’s theorem (infinitely many energies) largely answers Schroedinger’s false-negative coordinate dependence problem. Bauer’s nonuniqueness (false positive) objection has several answers.

Branching States as The Emergent Structure of a Quantum Universe. (arXiv:2208.05497v1 [quant-ph])

上午9:40 | | | Akram Touil, Fabio Anza, Sebastian Deffner, James P. Crutchfield | | | quant-ph updates on arXiv.org |

Quantum Darwinism builds on decoherence theory to explain the emergence of classical behavior within a quantum universe. We demonstrate that the differential geometric underpinnings of quantum mechanics provide a uniquely informative window into the structure of correlations needed to validate Quantum Darwinism. This leads us to two crucial insights about the emergence of classical phenomenology, centered around the nullity of quantum discord. First, we show that the so-called branching structure of the joint state of system and environment is the only one compatible with zero discord. Second, we prove that for small, but nonzero discord, the structure of the globally pure state is arbitrarily close to the branching form. These provide strong evidence that this class of branching states is the only one compatible with the emergence of classical phenomenology, as described in Quantum Darwinism.

Schr\”odinger’s cat meets Occam’s razor. (arXiv:0905.2723v3 [quant-ph] UPDATED)

上午9:40 | | | Richard D. Gill | | | quant-ph updates on arXiv.org |

We discuss V.P. Belavkin’s (2007) approach to the Schr\”odinger cat problem and show its close relation to ideas based on superselection and interaction with the environment developed by N.P. Landsman (1995). The purpose of the paper is to explain these ideas in the most simple possible context, namely: discrete time and separable Hilbert spaces, in order to make them accessible to those coming from the philosophy of science and not too happy with idiosyncratic notation and terminology and sophisticated mathematical tools. Conventional elementary mathematical descriptions of quantum mechanics take “measurement” to be a primitive concept. Paradoxes arise when we choose to consider smaller or larger systems as measurement devices in their own right, by making different and apparently arbitrary choices of location of the “Heisenberg cut”. Various quantum interpretations have different resolutions of the paradox. In Belavkin’s approach, the classical world around us does really exist, and it evolves stochastically and dynamically in time according to probability laws following from successive applications of the Born law. It is a collapse theory, and necessarily it is non-local. The quantum/classical distinction is determined by the arrow of time. The underlying unitary evolution of the wave-function of the universe enables the designation of a collection of beables which grows as time evolves, and which therefore can be assigned random, classical trajectories. In a slogan: the past is particles, the future is a wave. We, living in the now, are located on the cutting edge between past and future.

上午9:40 | | | Bibhas Ranjan Majhi | | | quant-ph updates on arXiv.org |

We put forward an attempt towards building a possible theoretical model to understand the observer dependent thermalization of black hole horizon. The near horizon Hamiltonian for a massless, chargeless particle is $xp$ type. This is unstable in nature and so the horizon can induce instability in a system. The particle in turn finds the horizon thermal when it interacts with it. We explicitly show this in the Schrodinger as well as in Heisenberg pictures by taking into account the time evolution of the system under this Hamiltonian. Hence we postulate that existing instability near the horizon can be one of the potential candidates for explaining the black hole thermalization.

上午9:40 | | | Zhihuang Luo, Wenzhao Zhang, Xinfang Nie, Dawei Lu | | | quant-ph updates on arXiv.org |

Topological phases have greatly improved our understanding of modern conception of phases of matter that go beyond the paradigm of symmetry breaking and are not described by local order parameters. Instead, characterization of topological phases requires the robust topological invariants, whereas measuring these global quantities presents an outstanding challenge for experiments, especially in interacting systems. Here we report the real-space observation of a symmetry-protected topological phase with interacting nuclear spins, and probe the interaction-induced transition between two topologically distinct phases, both of which are classified by many-body Chern numbers obtained from the dynamical response to the external magnetic fields. The resulting value of Chern number ($\bar{\mathcal{C}h} = 1.958 \pm 0.070$) demonstrates the robust ground state degeneracy, and also determines the number of nontrivial edge states. Our findings enable direct characterization of topological features of quantum many-body states through gradually decreasing the strength of the introduced external fields.

上午2:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2022) On Bell’s Everett (?) theory. Foundations of Physics. ISSN 0015-9018

No Quantum Threat to Relativity

上午2:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Le Bihan, Soazig (2020) No Quantum Threat to Relativity. UNSPECIFIED.

MOND and Meta-Empirical Theory Assessment

上午2:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

De Baerdemaeker, Siska and Dawid, Richard (2022) MOND and Meta-Empirical Theory Assessment. [Preprint]

For Whom the Bell Inequality Really Tolls

上午2:37 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Silberstein, Michael and Stuckey, W. M. and McDevitt, Timothy (2022) For Whom the Bell Inequality Really Tolls. [Preprint]

Why We Should Be Suspicious of Conspiracy Theories. A Novel Demarcation Problem

上午2:36 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Boudry, Maarten (2021) Why We Should Be Suspicious of Conspiracy Theories. A Novel Demarcation Problem. [Preprint]

2022年8月11日 星期四 上午8:00 | | | Christof Weitenberg | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 11 August 2022; doi:10.1038/s41567-022-01712-x

Statistical correlations between particles play a central role in the study of complex quantum systems. A new study introduces microscopic detection of ultracold molecules and demonstrates the measurement of two-particle correlations.

Thermodynamic Signatures of Genuinely Multipartite Entanglement

2022年8月9日 星期二 下午6:00 | | | Samgeeth Puliyil, Manik Banik, and Mir Alimuddin | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Samgeeth Puliyil, Manik Banik, and Mir Alimuddin

The theory of bipartite entanglement shares profound similarities with thermodynamics. In this Letter we extend this connection to multipartite quantum systems where entanglement appears in different forms with genuine entanglement being the most exotic one. We propose thermodynamic quantities that …

[Phys. Rev. Lett. 129, 070601] Published Tue Aug 09, 2022

The story of the tablecloth: deriving “before” from atemporal notions

2022年8月9日 星期二 上午6:27 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Saudek, Daniel (2022) The story of the tablecloth: deriving “before” from atemporal notions. [Preprint]

]]>上午10:42 | | | Pengyu Liu, Zhenhuan Liu, Shu Chen, Xiongfeng Ma | | | quant-ph updates on arXiv.org |

Entanglement detection is essential in quantum information science and quantum many-body physics. It has been proved that entanglement exists almost surely for a random quantum state, while the realizations of effective entanglement criteria usually consume exponential resources, and efficient criteria often perform poorly without prior knowledge. This fact implies a fundamental limitation might exist in the detectability of entanglement. In this work, we formalize this limitation as a fundamental trade-off between the efficiency and effectiveness of entanglement criteria via a systematic method to theoretically evaluate the detection capability of entanglement criteria. For a system coupled to an environment, we prove that any entanglement criterion needs exponentially many observables to detect the entanglement effectively when restricted to single-copy operations. Otherwise, the detection capability of the criterion will decay double-exponentially. Furthermore, if multi-copy joint measurements are allowed, the effectiveness of entanglement detection can be exponentially improved, which implies a quantum advantage in entanglement detection problems.

Bulk Locality and Asymptotic Causal Diamonds. (arXiv:1902.06709v3 [hep-th] UPDATED)

上午10:42 | | | Chethan Krishnan | | | quant-ph updates on arXiv.org |

In AdS/CFT, the non-uniqueness of the reconstructed bulk from boundary subregions has motivated the notion of code subspaces. We present some closely related structures that arise in flat space. A useful organizing idea is that of an {\em asymptotic} causal diamond (ACD): a causal diamond attached to the conformal boundary of Minkowski space. The space of ACDs is defined by pairs of points, one each on the future and past null boundaries, ${\cal I}^{\pm}$. We observe that for flat space with an IR cut-off, this space (a) encodes a preferred class of boundary “subregions”, (b) is a plausible way to capture holographic data for local bulk reconstruction, (c) has a natural interpretation as the kinematic space for holography, (d) leads to a holographic entanglement entropy in flat space that matches previous definitions and satisfies strong sub-additivity, and, (e) has a bulk union/intersection structure isomorphic to the one that motivated the introduction of quantum error correction in AdS/CFT. By sliding the cut-off, we also note one substantive way in which flat space holography differs from that in AdS. Even though our discussion is centered around flat space (and AdS), we note that there are notions of ACDs in other spacetimes as well. They could provide a covariant way to abstractly characterize tensor sub-factors of Hilbert spaces of holographic theories.

上午10:42 | | | Oded Shor, Felix Benninger, Andrei Khrennikov | | | quant-ph updates on arXiv.org |

Quantum mechanics (QM) is derived based on a universe composed solely of events, for example, outcomes of observables. Such an event universe is represented by a dendrogram (a finite tree) and in the limit of infinitely many events by the p-adic tree. The trees are endowed with an ultrametric expressing hierarchical relationships between events. All events are coupled through the tree structure. Such a holistic picture of event-processes was formalized within the Dendrographic Hologram Theory (DHT). The present paper is devoted to the emergence of QM from DHT. We used the generalization of the QM-emergence scheme developed by Smolin. Following this scheme, we did not quantize events but rather the differences between them and through analytic derivation arrived at Bohmian mechanics. Previously, we were able to embed the basic elements of general relativity (GR) into DHT, and now after Smolin-like quantization of DHT, we can take a step toward quantization of GR. Finally, we remark that DHT is nonlocal in the treelike geometry, but this nonlocality refers to relational nonlocality in the space of events and not Einstein’s spatial nonlocality.

上午10:42 | | | Seunghoon Lee, Joonho Lee, Huanchen Zhai, Yu Tong, Alexander M. Dalzell, Ashutosh Kumar, Phillip Helms, Johnnie Gray, Zhi-Hao Cui, Wenyuan Liu, Michael Kastoryano, Ryan Babbush, John Preskill, David R. Reichman, Earl T. Campbell, Edward F. Valeev, Lin Lin, Garnet Kin-Lic Chan | | | quant-ph updates on arXiv.org |

The idea to use quantum mechanical devices to simulate other quantum systems is commonly ascribed to Feynman. Since the original suggestion, concrete proposals have appeared for simulating molecular and materials chemistry through quantum computation, as a potential “killer application”. Indications of potential exponential quantum advantage in artificial tasks have increased interest in this application, thus, it is critical to understand the basis for potential exponential quantum advantage in quantum chemistry. Here we gather the evidence for this case in the most common task in quantum chemistry, namely, ground-state energy estimation. We conclude that evidence for such an advantage across chemical space has yet to be found. While quantum computers may still prove useful for quantum chemistry, it may be prudent to assume exponential speedups are not generically available for this problem.

上午10:42 | | | physics.hist-ph updates on arXiv.org |

Authors: Raoni Wohnrath Arroyo

This book deals with some ontological implications of standard non-relativistic quantum mechanics, and the use of the notion of `consciousness’ to solve the measurement problem.

Advanced General Relativity Notes. (arXiv:2208.02506v1 [gr-qc])

上午10:42 | | | gr-qc updates on arXiv.org |

Authors: M. Le Delliou

These lecture notes are intended as a guide to Graduate level readers that are already familiar with basic General Relativity. They present in a concise way some advanced concepts and problems encountered in the study of gravitation. In these notes are covered: Alternates forms of the Schwarzschild Black Hole solution, including the classic Kruskal extension; An account of the building of Conformal, Carter-Penrose, diagrams; A discussion of Birkhoff Theorem; A discussion of tools for Geodesics and congruences, including Energy Conditions; A discussion of Horizons and an approach to some of the singularity theorems; An exploration of the Kerr Black Hole solution properties, including the Penrose Process and Black Hole Thermodynamics; A discussion of the Eckart and Israel-Stewart Relativistic Thermodynamics; A discussion of Tetrads in Relativity, in Einstein-Cartan theory and in Newman-Penrose formalism; An explicitation of calculations on Geodesics approach from Hamilton-Jacobi Formalism; A derivation from Least action of the equation of Motion of a top in Relativity, the M.P.D. equations

UV And IR Effects On Hawking Radiation. (arXiv:2207.07122v2 [hep-th] UPDATED)

上午10:42 | | | gr-qc updates on arXiv.org |

Authors: Pei-Ming Ho, Hikaru Kawai

We study the time-dependence of Hawking radiation for a black hole in the Unruh vacuum, and find that it is not robust against certain UV and IR effects. If there is a UV cutoff at the Planck scale, Hawking radiation is turned off after the scrambling time. In the absence of a UV cutoff, Hawking radiation is sensitive to the IR cutoff through a UV/IR connection due to higher-derivative interactions in the effective theory. Furthermore, higher-derivative interactions with the background contribute to a large amplitude of particle creation that changes Hawking radiation. This unexpected large effect is related to a peculiar feature of the Hawking particle wave packets.

上午10:42 | | | gr-qc updates on arXiv.org |

Authors: Christoph Schiller

A compact summary of present fundamental physics is given and evaluated. Its 9 lines contain both general relativity and the standard model of particle physics. Their precise agreement with experiments, in combination with their extreme simplicity and their internal consistency, suggest that there are no experimental effects beyond the two theories. The combined properties of the 9 lines also imply concrete suggestions for the search for a theory of quantum gravity. Finally, the 9 lines specify the only decisive tests that allow checking any specific proposal for such a theory.

Why It Matters that Idealizations Are False

上午9:46 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Potochnik, Angela (2020) Why It Matters that Idealizations Are False. [Preprint]

High-Dimensional Bell Test without Detection Loophole

2022年8月3日 星期三 下午6:00 | | | Xiao-Min Hu, Chao Zhang, Bi-Heng Liu, Yu Guo, Wen-Bo Xing, Cen-Xiao Huang, Yun-Feng Huang, Chuan-Feng Li, and Guang-Can Guo | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Xiao-Min Hu, Chao Zhang, Bi-Heng Liu, Yu Guo, Wen-Bo Xing, Cen-Xiao Huang, Yun-Feng Huang, Chuan-Feng Li, and Guang-Can Guo

Violation of Bell’s inequalities shows strong conflict between quantum mechanics and local realism. Loophole-free Bell tests not only deepen understanding of quantum mechanics, but are also important foundations for device-independent (DI) tasks in quantum information. High-dimensional quantum syste…

[Phys. Rev. Lett. 129, 060402] Published Wed Aug 03, 2022

Understanding Time Reversal in Quantum Mechanics: A Full Derivation

2022年8月3日 星期三 下午4:02 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2022) Understanding Time Reversal in Quantum Mechanics: A Full Derivation. [Preprint]

On the unreasonable reliability of mathematical inference

2022年8月3日 星期三 上午8:00 | | | Latest Results for Synthese |

**Abstract**

In (Avigad, 2020), Jeremy Avigad makes a novel and insightful argument, which he presents as part of a defence of the ‘Standard View’ about the relationship between informal mathematical proofs (that is, the proofs that mathematicians write for each other and publish in mathematics journals, which may in spite of their ‘informal’ label be rather more formal than other kinds of scientific communication) and their corresponding formal derivations (‘formal’ in the sense of computer science and mathematical logic). His argument considers the various strategies by means of which mathematicians can write informal proofs that meet mathematical standards of rigour, in spite of the prodigious length, complexity and conceptual difficulty that some proofs exhibit. He takes it that showing that and how such strategies work is a necessary part of any defence of the Standard View.

In this paper, I argue for two claims. The first is that Avigad’s list of strategies is no threat to critics of the Standard View. On the contrary, this observational core of heuristic advice in Avigad’s paper is agnostic between rival accounts of mathematical correctness. The second is that that Avigad’s project of accounting for the relation between formal and informal proofs requires an answer to a prior question: what sort of thing is an informal proof? His paper havers between two answers. One is that informal proofs are ultimately syntactic items that differ from formal derivations only in completeness and use of abbreviations. The other is that informal proofs are not purely syntactic items, and therefore the translation of an informal proof into a derivation is not a routine procedure but rather a creative act. Since the ‘syntactic’ reading of informal proofs reduces the Standard View to triviality, makes a mystery of the valuable observational core of his paper, and underestimates the value of the achievements of mathematical logic, he should choose some version of the second option.

Experimental Demonstration of Genuine Tripartite Nonlocality under Strict Locality Conditions

2022年8月2日 星期二 下午6:00 | | | Liang Huang, Xue-Mei Gu, Yang-Fan Jiang, Dian Wu, Bing Bai, Ming-Cheng Chen, Qi-Chao Sun, Jun Zhang, Sixia Yu, Qiang Zhang, Chao-Yang Lu, and Jian-Wei Pan | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Liang Huang, Xue-Mei Gu, Yang-Fan Jiang, Dian Wu, Bing Bai, Ming-Cheng Chen, Qi-Chao Sun, Jun Zhang, Sixia Yu, Qiang Zhang, Chao-Yang Lu, and Jian-Wei Pan

Nonlocality captures one of the counterintuitive features of nature that defies classical intuition. Recent investigations reveal that our physical world’s nonlocality is at least tripartite; i.e., genuinely tripartite nonlocal correlations in nature cannot be reproduced by any causal theory involvi…

[Phys. Rev. Lett. 129, 060401] Published Tue Aug 02, 2022

2022年8月2日 星期二 下午3:10 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Adlam, Emily (2022) Is There Causation in Fundamental Physics? New Insights from Process Matrices and Quantum Causal Modelling. [Preprint]

Rethinking conspiracy theories

2022年8月2日 星期二 上午8:00 | | | Latest Results for Synthese |

**Abstract**

I argue that that an influential strategy for understanding conspiracy theories stands in need of radical revision. According to this approach, called ‘generalism’, conspiracy theories are epistemically defective by their very nature. Generalists are typically opposed by particularists, who argue that conspiracy theories should be judged case-by-case, rather than definitionally indicted. Here I take a novel approach to criticizing generalism. I introduce a distinction between ‘Dominant Institution Conspiracy Theories and Theorists’ and ‘Non-Dominant Institution Conspiracy Theories and Theorists’. Generalists uncritically center the latter in their analysis, but I show why the former must be centered by generalists’ own lights: they are the clearest representatives of their views, and they are by far the most harmful. Once we make this change in paradigm cases, however, various typical generalist theses turn out to be false or in need of radical revision. Conspiracy theories are not primarily produced by extremist ideologies, as generalists typically claim, since mainstream, purportedly non-extremist political ideologies turn out to be just as, if not more responsible for such theories. Conspiracy theories are also, we find, not the province of amateurs: they are often created and pushed by individuals widely viewed as experts, who have the backing of our most prestigious intellectual institutions. While generalists may be able to take this novel distinction and shift in paradigm cases on board, this remains to be seen. Subsequent generalist accounts that do absorb this distinction and shift will look radically different from previous incarnations of the view.

Physicalism without the idols of mathematics

2022年8月2日 星期二 上午6:55 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Szabo, Laszlo E. (2021) Physicalism without the idols of mathematics. [Preprint]

An Armstrongian Defense of Dispositional Monist Accounts of Laws of Nature

2022年7月31日 星期日 下午3:44 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Mohammadian, Mousa (2022) An Armstrongian Defense of Dispositional Monist Accounts of Laws of Nature. [Preprint]

]]>上午9:19 | | | Philippe Faist, Mischa P. Woods, Victor V. Albert, Joseph M. Renes, Jens Eisert, John Preskill | | | quant-ph updates on arXiv.org |

Detection of weak forces and precise measurement of time are two of the many applications of quantum metrology to science and technology. We consider a quantum system initialized in a pure state and whose evolution is goverened by a Hamiltonian $H$; a measurement can later estimate the time $t$ for which the system has evolved. In this work, we introduce and study a fundamental trade-off which relates the amount by which noise reduces the accuracy of a quantum clock to the amount of information about the energy of the clock that leaks to the environment. Specifically, we consider an idealized scenario in which Alice prepares an initial pure state of the clock, allows the clock to evolve for a time $t$ that is not precisely known, and then transmits the clock through a noisy channel to Bob. The environment (Eve) receives any information that is lost. We prove that Bob’s loss of quantum Fisher information (QFI) about $t$ is equal to Eve’s gain of QFI about a complementary energy parameter. We also prove a more general trade-off that applies when Bob and Eve wish to estimate the values of parameters associated with two non-commuting observables. We derive the necessary and sufficient conditions for the accuracy of the clock to be unaffected by the noise. These are a subset of the Knill-Laflamme error-correction conditions; states satisfying these conditions are said to form a metrological code. We provide a scheme to construct metrological codes in the stabilizer formalism. We show that there are metrological codes that cannot be written as a quantum error-correcting code with similar distance in which the Hamiltonian acts as a logical operator, potentially offering new schemes for constructing states that do not lose any sensitivity upon application of a noisy channel. We discuss applications of our results to sensing using a many-body state subject to erasure or amplitude-damping noise.

Post-selection and quantum energetics. (arXiv:2207.14194v1 [quant-ph])

上午9:19 | | | Spencer Rogers, Andrew N. Jordan | | | quant-ph updates on arXiv.org |

We investigate the anomalous energy change of the measurement apparatus when a qubit is measured in bases that do not commute with energy. We model two possible measurement implementations: one is a quantum clock model with a completely time-independent Hamiltonian, while the other is a Jaynes-Cummings model which is time-dependent but conserves the total excitation number. We look at the mean energy change of the measurement apparatus in both models, conditioned on the qubit post-selection, and find that this change can be much greater than the level spacing of the qubit, like an anomalous weak value. In the clock model, the expression for the apparatus energy shift explicitly contains the weak value of the qubit Hamiltonian. However, in our case, no explicit weak measurements are carried out. Our two models give different results, which we explain to be a consequence of the non-degenerate spectrum of the Jaynes-Cummings model. We compare our calculations in the Jaynes-Cummings model with the experimental data of [J. Stevens, et al, arXiv:2109.09648 (2021)] and find good agreement when the conditions of our derivation are valid.

Black Hole as a Bound State of Semi-classical Degrees of Freedom. (arXiv:2207.14274v1 [hep-th])

上午9:19 | | | Yuki Yokokura | | | quant-ph updates on arXiv.org |

A black hole is considered as a bound state of semi-classical degrees of freedom with maximum gravity. For a configuration of those responsible for the area entropy, the information distribution determines the interior metric through the semi-classical Einstein equation. Then, the bound state has no horizon or singularity, and the interior is a continuous stacking of $AdS_2\times S^2$ with a $AdS$ radius close to the Planck length and behaves like a thermal state at a near-Planckian local temperature. Integrating the entropy density over the interior volume reproduces the area law exactly. This indicates that the dynamics of gravity plays an essential role in the change of entropy from the volume law to the area law.

On the Free Will Theorem. (arXiv:2207.06295v2 [quant-ph] UPDATED)

上午9:19 | | | Simon Kochen | | | quant-ph updates on arXiv.org |

We strengthen the Free Will Theorem, which proved the spontaneity of particles, based on the free will of the experimenter. The new result is unconditional, and does not require the experimenter’s free will to prove the particles’ spontaneity.

Time, space and matter in the primordial universe. (arXiv:2207.13722v1 [physics.hist-ph])

上午9:19 | | | physics.hist-ph updates on arXiv.org |

Authors: Francesca Vidotto

Time, space, and matter are categories of our reasoning, whose properties appear to be fundamental. However, these require a scrutiny as in the extreme regime of the primordial universe these present quantum properties. What does it mean for time to be quantum? What does it mean for space? Are space and time disappearing, or what is disappearing are simply the categories we have been using to understand them? Concepts such as the superposition of causal structures or the quantum granularity of space require our attention and should be clarified to understand the physics of the primordial universe. The novelty that this brings requires us to reflect on matter as well: How can matter be defined on a granular space? Is quantum gravity hinting us toward considering new types of matter? The answers to these questions, that touch the foundations of physics and the very concepts with which we organize our understanding of reality, require in the end of the journey to confront ourselves with empirical data. And for that, the universe itself provides us with the best of possible laboratories.

上午9:19 | | | gr-qc updates on arXiv.org |

Authors: Carlo Cepollaro, Flaminia Giacomini

The Einstein Equivalence Principle (EEP) is of crucial importance to test the foundations of general relativity. When the particles involved in the test exhibit quantum properties, it is unknown whether this principle still holds. A possibility introduced in arXiv:2012.13754 is that the EEP holds in a generalised form for particles having an arbitrary quantum state. The core of this proposal is the ability to transform to a Quantum Reference Frame (QRF) associated to an arbitrary quantum state of a physical system, in which the metric is locally inertial. Here, we show that this extended EEP, initially formulated in terms of the local expression of the metric field in a QRF, can be verified in an interferometric setup via tests on the proper time of entangled clocks. We find that the violation of the generalised EEP corresponds to the impossibility of defining dynamical evolution in the frame of each clock. The violation results in a modification to the probabilities of measurements calculated in the laboratory frame, and hence can be verified in an interferometric setting.

Pantheon+ tomography and Hubble tension. (arXiv:2207.10927v2 [astro-ph.CO] UPDATED)

上午9:19 | | | gr-qc updates on arXiv.org |

Authors: Deng Wang

The recently released Type Ia supernovae (SNe Ia) sample, Pantheon+, is an updated version of Pantheon and has very important cosmological implications. To explore the origin of the enhanced constraining power and internal correlations of datasets in different redshifts, we perform a comprehensively tomographic analysis of the Pantheon+ sample. Using the Pantheon+ data alone, we give the $2\,\sigma$ lower bound on the Hubble constant $H_0>45.7$ km s$^{-1}$ Mpc$^{-1}$ and the matter fraction $\Omega_m=0.367\pm0.030$, which shows the evidence of dark energy at the $21\,\sigma$ confidence level but is in a $1.7\,\sigma$ tension with that from the Planck-2018 measurement. Combining the Pantheon+ sample with cosmic microwave background, baryon acoustic oscillations, cosmic chronometers, galaxy clustering and weak lensing data, we give the strongest constraint $H_0=67.88\pm0.42$ km s$^{-1}$ Mpc$^{-1}$ at the $1\,\sigma$ confidence level. After dividing the full sample to 10 bins, we find that the first bin in the redshift range $z\in[0.00122, \, 0.227235]$ dominates the constraining power of the whole sample. We also investigate the effects of low-z and high-z subsamples of Pantheon+ on $H_0$ and $\Omega_{m}$, and find that low-z SNe Ia do not have enough constraining power until $z\sim0.1$. Interestingly, high-z SNe Ia in the redshift range $z>0.227235$ can give an competitive constraint on $\Lambda$CDM when compared to three low-z bins. We expect that future high-precision SNe Ia data can independently determine both $H_0$ and $\Omega_{m}$.

Quantifying Nonlocality: How Outperforming Local Quantum Codes Is Expensive

2022年7月28日 星期四 下午6:00 | | | Nouédyn Baspin and Anirudh Krishna | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Nouédyn Baspin and Anirudh Krishna

Quantum low-density parity-check (LDPC) codes are a promising avenue to reduce the cost of constructing scalable quantum circuits. However, it is unclear how to implement these codes in practice. Seminal results of Bravyi *et al.* [Phys. Rev. Lett. **104**, 050503 (2010)] have shown that quantum LDPC code…

[Phys. Rev. Lett. 129, 050505] Published Thu Jul 28, 2022

Chiral cavity quantum electrodynamics

2022年7月28日 星期四 上午8:00 | | | David I. Schuster | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 28 July 2022; doi:10.1038/s41567-022-01671-3

Edge modes in chiral topological systems can carry quantum information without backscattering. A topological lattice of superconducting resonators has been coupled to a qubit, providing a platform for chiral quantum electrodynamics and communication.

Renormalization group methods and the epistemology of effective field theories

2022年7月27日 星期三 上午7:53 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Koberinski, Adam and Fraser, Doreen (2022) Renormalization group methods and the epistemology of effective field theories. [Preprint]

A simple proof that the global phase is real

2022年7月27日 星期三 上午7:51 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2022) A simple proof that the global phase is real. [Preprint]

A broken translational symmetry state in an infinite-layer nickelate

2022年7月25日 星期一 上午8:00 | | | Wei-Sheng Lee | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 25 July 2022; doi:10.1038/s41567-022-01660-6

Unconventional superconductivity is often associated with the presence of other kinds of electronic order. Observations of charge order in infinite-layer nickelate superconductors show that they fit this pattern.

Prolongments of “Ensaio”: Schrödinger Logics and Quasi-Set Theory

2022年7月25日 星期一 上午4:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Krause, Décio (2022) Prolongments of “Ensaio”: Schrödinger Logics and Quasi-Set Theory. [Preprint]

On the discrepancies between quantum logic and classical logic

2022年7月25日 星期一 上午4:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Krause, Décio (2022) On the discrepancies between quantum logic and classical logic. [Preprint]

2022年7月24日 星期日 下午11:57 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Allori, Valia (2022) What is it Like to be a Relativistic GRW Theory? Or: Quantum Mechanics and Relativity, Still in Conflict After All These Years. [Preprint]

]]>上午10:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Fernandes, Alison (2022) How to Explain the Direction of Time. [Preprint]

上午8:55 | | | Joshua Combes, Austin P. Lund | | | quant-ph updates on arXiv.org |

Homodyne measurements are a widely used quantum measurement. Using a coherent state of large amplitude as the local oscillator, it can be shown that the quantum homodyne measurement limits to a field quadrature measurement. In this work, we give an example of a general idea: injecting non-classical states as a local oscillator can led to non-classical measurements. Specifically, we consider injecting a superposition of coherent states, a Schr\”odinger cat state, as a local oscillator. We derive the Kraus operators and the positive operator-valued measure (POVM) in this situation and show the POVM is a reflection symmetric quadrature measurement when the coherent state amplitudes are large.

上午8:55 | | | Pasquale Bosso, Luciano Petruzziello, Fabian Wagner, Fabrizio Illuminati | | | quant-ph updates on arXiv.org |

Different approaches to quantum gravity converge in predicting the existence of a minimal scale of length. This raises the fundamental question as to whether and how an intrinsic limit to spatial resolution can affect quantum mechanical observables associated to internal degrees of freedom. We answer this question in general terms by showing that the spin operator acquires a momentum-dependent contribution in quantum mechanics equipped with a minimal length. Among other consequences, this modification induces a form of quantum nonlocality stronger than the one arising in ordinary quantum mechanics. In particular, we show that violations of the Bell inequality can exceed the maximum value allowed in ordinary quantum mechanics by a positive multiplicative function of the momentum operator.

Quantum States of Fields for Quantum Split Sources. (arXiv:2207.10592v1 [gr-qc])

上午8:55 | | | Lin-Qing Chen, Flaminia Giacomini, Carlo Rovelli | | | quant-ph updates on arXiv.org |

Field mediated entanglement experiments probe the quantum superposition of macroscopically distinct field configurations. We show that this phenomenon can be described by using a transparent quantum field theoretical formulation of electromagnetism and gravity in the field basis. The strength of such a description is that it explicitly displays the superposition of macroscopically distinct states of the field. In the case of (linearised) quantum general relativity, this formulation exhibits the quantum superposition of geometries giving rise to the effect.

Teaching Qubits to Sing: Mission Impossible?. (arXiv:2207.08225v2 [quant-ph] UPDATED)

上午8:55 | | | Eduardo Reck Miranda, Brian N. Siegelwax | | | quant-ph updates on arXiv.org |

This paper introduces a system that learns to sing new tunes by listening to examples. It extracts sequencing rules from input music and uses these rules to generate new tunes, which are sung by a vocal synthesiser. We developed a method to represent rules for musical composition as quantum circuits. We claim that such musical rules are quantum native: they are naturally encodable in the amplitudes of quantum states. To evaluate a rule to generate a subsequent event, the system builds the respective quantum circuit dynamically and measures it. After a brief discussion about the vocal synthesis methods that we have been experimenting with, the paper introduces our novel generative music method through a practical example. The paper shows some experiments and concludes with a discussion about harnessing the creative potential of the system.

On the maximum size of black holes in our accelerating universe. (arXiv:2207.10202v1 [gr-qc])

上午8:55 | | | gr-qc updates on arXiv.org |

Authors: Tetsuya Shiromizu, Keisuke Izumi, Kangjae Lee, Diego Soligon

In accordance with current models of the accelerating universe as a spacetime with a positive cosmological constant, new results about a cosmological upper bound for the area of stable marginally outer trapped surfaces are found taking into account angular momentum, gravitational waves and matter. Compared to previous results which take into account only some of the aforementioned variables, the bound is found to be tighter, giving a concrete limit to the size of black holes especially relevant in the early universe.

上午8:55 | | | gr-qc updates on arXiv.org |

Authors: Oem Trivedi

The Hubble tension is one of the most exciting problems that Cosmology faces today. A lot of possible solutions for it have already been proposed in the last few years, with a lot of them using a lot of new and exotic physics ideas to deal with the problem. But it was shown recently that the H0 tension might not require new physics but only a more accurate discussion of measurements and interestingly it was the Heisenberg uncertainty principle which was pivotal for that revelation. Accordingly, if one observed the photon mass beyond the indeterminacy through uncertainty then one could in principle reconcile the tension. We examine this in a greater detail in this work by taking into account modifications of the Compton wavelength, which was pivotal in the initial discussion on the interconnection between uncertainty and the H0 tension. We mainly discuss two types of modifications, one based on generalized uncertainty principles (GUP) and the other on higher dimensional physics considerations. We firstly show that both minimal length and maximal momentum GUP based modifications do not provide photon mass values on the required scales and hence we cannot address the tension in this sense at all in this case. We then show that one can get the photon mass to be on the required scales even after incorporating higher dimensional effects, one cannot reconcile the Hubble Tension in the same sense as in the (3+1) space-time case. In this way, we show that certain new physics considerations cannot address the H0 tension in the same sense as one can using the original Heisenberg uncertainty principle in a (3+1) space-time.

上午8:55 | | | gr-qc updates on arXiv.org |

Authors: Jan de Boer, Bianca Dittrich, Astrid Eichhorn, Steven B. Giddings, Steffen Gielen, Stefano Liberati, Etera R. Livine, Daniele Oriti, Kyriakos Papadodimas, Antonio D. Pereira, Mairi Sakellariadou, Sumati Surya, Herman Verlinde

Understanding the quantum nature of spacetime and gravity remains one of the most ambitious goals of theoretical physics. It promises to provide key new insights into fundamental particle theory, astrophysics, cosmology and the foundations of physics. Despite this common goal, the community of quantum gravity researchers is sometimes seen as divided into sub-communities working on different, mutually exclusive approaches. In practice however, recent years have shown the emergence of common techniques, results and physical ideas arising from different sub-communities, suggesting exciting new prospects for collaboration and interaction between traditionally distinct approaches. In this White Paper we discuss some of the common themes which have seen a growing interest from various directions, and argue that focusing on them will help the quantum gravity community as a whole towards shared objectives.

Quantized mass-energy effects in an Unruh-DeWitt detector. (arXiv:2205.02394v2 [quant-ph] UPDATED)

上午8:55 | | | gr-qc updates on arXiv.org |

Authors: Carolyn E. Wood, Magdalena Zych

A simple but powerful particle detector model consists of a two-level system coupled to a field, where the detected particles are the field excitations. This is known as the Unruh-DeWitt detector. Research using this model has often focused on either a completely classical description of the external degrees of freedom of the detector, or a full field-theoretic treatment, where the detector itself is described as a field. Recently there has been much interest in quantum aspects of the detector’s center of mass — either described as moving in superposition along semiclassical trajectories, or dynamically evolving under a non-relativistic Hamiltonian. However, the processes of interest — the absorption or emission of field particles — necessarily change the detector’s rest mass by the amount of energy of the absorbed or emitted field quanta. Neither of the above models can capture such effects. Here we incorporate the quantization of the detector’s mass-energy into the Unruh-DeWitt model. We show that internal energy changes due to emission or absorption are relevant even in the lowest energy limit. Specifically, corrections to transition rates due to the detector’s mass changing cannot be ignored unless the entire center of mass dynamics is also ignored. Our results imply that one cannot have a consistent model of the Unruh-DeWitt detector as a massive particle without including the mass-energy equivalence.

Determinism and Chance from a Humean Perspective

2022年7月20日 星期三 上午1:02 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Frigg, Roman and Hoefer, Carl (2010) Determinism and Chance from a Humean Perspective.

Properties and the Born Rule in GRW Theory

2022年7月20日 星期三 上午1:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Frigg, Roman (2018) Properties and the Born Rule in GRW Theory. Collapse of the Wave Function: Models, Ontology, Origin, and Implications..

Exact Solution of the Macroscopic Fluctuation Theory for the Symmetric Exclusion Process

2022年7月19日 星期二 下午6:00 | | | Kirone Mallick, Hiroki Moriya, and Tomohiro Sasamoto | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Kirone Mallick, Hiroki Moriya, and Tomohiro Sasamoto

We present the first exact solution for the time-dependent equations of the macroscopic fluctuation theory (MFT) for the symmetric simple exclusion process by combining a generalization of the canonical Cole-Hopf transformation with the inverse scattering method. For the step initial condition with …

[Phys. Rev. Lett. 129, 040601] Published Tue Jul 19, 2022

Gao, Shan (2022) *Quantum suicide and many worlds.* [Preprint]

Werndl, Charlotte and Frigg, Roman (2020) *Taming Abundance: on the Relation between Boltzmannian and Gibbsian Statistical Mechanics.* Statistical Mechanics and Scientific Explanation: Determinism, Indeterminism and Laws of Nature. pp. 617-646.

Frigg, Roman and Werndl, Charlotte (2019) *Statistical Mechanics:A Tale of Two Theories.* The Monist. pp. 424-438.

Frigg, Roman and Werndl, Charlotte (2020) *Boltzmannian Non-Equilibrium and Local Variables.* [Preprint]