上午8:59 | | | Tabish Qureshi | | | quant-ph updates on arXiv.org |

Recent times have seen a spurt of research activity focused on “completing” certain wave-particle duality relations using entanglement or polarization. These studies use a duality relation involving path-predictability, and not path-distinguishability. Quantum origins of these results are explored here, in the more general framework of multipath quantum interference. Multipath interference with a path-detector is theoretically analyzed to find the connection between predictability and distinguishability. It is shown that entanglement is what quantitatively connects distinguishability with predictability. Thus, a duality relation between distinguishability and coherence, can also be viewed as a triality between predictability, entanglement and coherence. There exist two different kind of duality relations in the literature, which pertain to two different kinds of interference experiments, with or without a path-detector. Results of this study show that the two duality relations are quantitatively connected via entanglement. The roots of the new results in the classical optical domain, including the polarization coherence theorem, can be understood in the light of this work. Additionally, the triality relations obtained can quantify wave-particle duality in the interesting case of a quanton with an internal degree of freedom. The relations can also be employed to experimentally determine the degree of bipartite entanglement.

上午8:59 | | | Emily Adlam | | | quant-ph updates on arXiv.org |

We demonstrate that in a globally deterministic universe, all spatiotemporally symmetric processes must obey counterfactual parameter independence. We show that the Tsirelson bound can be derived from counterfactual parameter independence. We show that the quantum monogamy bound can also be obtained from global determinism, and then then use these results to propose a novel solution to the horizon problem. We also explain how global determinism relates to contextuality in quantum mechanics.

上午8:59 | | | L. M. Arévalo Aguilar | | | quant-ph updates on arXiv.org |

In 1927, at the Solvay conference, Einstein posed a thought experiment with the primary intention of showing the incompleteness of quantum mechanics; to prove it, he uses the instantaneous nonlocal effects caused by the collapse of the wave function of a single particle -the spooky action at a distance-, when a measurement is done. This historical event precede the well-know Einstein-Podolsk-Rosen criticism over the incompleteness of quantum mechanics. Here, by using the Stern-Gerlach experiment (SGE), we demonstrate how the instantaneous nonlocal feature of the collapse of the wave function together with the single-particle entanglement can be used to produce the nonlocal effect of steering. In the steering process Bob gets a quantum state depending on which observable Alice decides to measure. To accomplish this, we fully exploit the spreading (over large distances) of the entangled wave function of the single-particle. In particular, we demonstrate that the nonlocality of the single-particle entanglement allows the particle to know which detector Alice is using to steer Bob’s state. Therefore, notwithstanding strong counterarguments, we prove that the single-particle entanglement gives rise to truly nonlocal effects at two far a away places. This open the possibility of using the single-particle entanglement for implementing truly nonlocal task.

Are temporal quantum correlations generally non-monogamous?. (arXiv:2011.08437v1 [quant-ph])

上午8:59 | | | Marcin Nowakowski | | | quant-ph updates on arXiv.org |

In this paper we focus on the underlying quantum structure of temporal correlations and show their peculiar nature which differentiate them from spatial quantum correlations. We show rigorously that a particular entangled history, which can be associated with a quantum propagator, is monogamous to conserve its consistency throughout time. Yet evolving systems violate monogamous Bell-like multi-time inequalities. This dichotomy, being a novel feature of temporal correlations, has its roots in the measurement process itself which is discussed by means of the bundles of entangled histories. We introduce and discuss a concept of a probabilistic mixture of quantum processes by means of which we clarify why the spatial-like Bell-type monogamous inequalities are further violated. We prove that Tsirelson bound on temporal Bell-like inequalities can be derived from the entangled histories approach and as a generalization, we derive the quantum bound for multi-time Bell-like inequalities. It is also pointed out that what mimics violation of monogamy of temporal entanglement is actually just a kind of polyamory in time but monogamy of entanglement for a particular evolution still holds.

上午8:59 | | | A. Vinante, G. Gasbarri, C. Timberlake, M. Toroš, H. Ulbricht | | | quant-ph updates on arXiv.org |

We present experimental tests of dissipative extensions of spontaneous wave function collapse models based on a levitated micromagnet with ultralow dissipation. The spherical micromagnet, with radius $R=27$ $\mu$m, is levitated by Meissner effect in a lead trap at $4.2$ K and its motion is detected by a SQUID. We perform accurate ringdown measurements on the vertical translational mode with frequency $57$ Hz, and infer the residual damping at vanishing pressure $\gamma/2\pi<9$ $\mu$Hz. From this upper limit we derive improved bounds on the dissipative versions of the CSL (continuous spontaneous localization) and the DP (Di\'{o}si-Penrose) models with proper choices of the reference mass. In particular, dissipative models give rise to an intrinsic damping of an isolated system with the effect parameterized by a temperature constant; the dissipative CSL model with temperatures below 1 nK is ruled out, while the dissipative DP model is excluded for temperatures below $10^{-13}$ K. Furthermore, we present the first bounds on dissipative effects in a more recent model, which relates the wave function collapse to fluctuations of a generalized complex-valued spacetime metric.

上午8:59 | | | physics.hist-ph updates on arXiv.org |

Authors: Jochen Szangolies

In [Found. Phys. 48.12 (2018): 1669], the notion of ‘epistemic horizon’ was introduced as an explanation for many of the puzzling features of quantum mechanics. There, it was shown that Lawvere’s theorem, which forms the categorical backdrop to phenomena such as G\”odelian incompleteness, Turing undecidability, Russell’s paradox and others, applied to a measurement context, yields bounds on the maximum knowledge that can be obtained about a system, which produces many paradigmatically quantum phenomena. We give a brief presentation of the framework, and then demonstrate how it naturally yields Bell inequality violations. We then study the argument due to Einstein, Podolsky, and Rosen, and show how the counterfactual inference needed to conclude the incompleteness of the quantum formalism is barred by the epistemic horizon. Similarly, the paradoxes due to Hardy and Frauchiger-Renner are discussed, and found to turn on an inconsistent combination of information from incompatible contexts.

The Unruh effect in slow motion. (arXiv:2011.08223v1 [quant-ph])

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Silas Vriend, Daniel Grimmer, Eduardo Martín-Martínez

We show under what conditions an accelerated detector (e.g., an atom/ion/molecule) thermalizes while interacting with the vacuum state of a quantum field in a setup where the detector’s acceleration alternates sign across multiple optical cavities. We show (non-perturbatively) in what regimes the probe `forgets’ that it is traversing cavities and thermalizes to a temperature proportional to its acceleration. Then we analyze in detail how this thermalization relates to the renowned Unruh effect. Finally, we use these results to propose an experimental testbed for the direct detection of the Unruh effect at relatively low probe speeds and accelerations, potentially orders of magnitude below previous proposals.

Weighing the Vacuum Energy. (arXiv:2011.08231v1 [hep-th])

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Enrique Alvarez, Jesus Anero, Raquel Santos-Garcia

We discuss the weight of vacuum energy in various contexts. First, we compute the vacuum energy for flat spacetimes of the form $\mathbb{T}^3 \times \mathbb{R}$, where $\mathbb{T}^3$ stands for a general 3-torus. We discover a quite simple relationship between energy at radius $R$ and energy at radius ${l_s^2\over R}$. Then we consider quantum gravity effects in the vacuum energy of a scalar field in $\mathbb{M}_3 \times S^1$ where $\mathbb{M}_3$ is a general curved spacetime. We compute it for General Relativity and generic transverse {\em TDiff} theories. In the particular case of Unimodular Gravity vacuum energy does not gravitate.

Gravitational decoherence of photons. (arXiv:2011.08270v1 [gr-qc])

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Michalis Lagouvardos, Charis Anastopoulos

Models of gravitational decoherence are not commonly applied to ultra-relativistic systems, including photons. As a result, few quantum optical tests of gravitational decoherence have been developed. In this paper, we generalize the gravitational decoherence model of Anastopoulos and Hu (arXiv:1305.5231 [gr-qc]) to photons. In this model, decoherence originates from a bath of stochastic gravitational perturbations, possibly of fundamental origin. We derive a master equation for general states of the electromagnetic (EM) field; the only free parameter is a noise temperature $\Theta$ of the gravitational fluctuations. We find that interference experiments with long baselines, accessible in near-future experiments, can, in principle, lead to strong constraints in $\Theta$.

From the Black Hole Conundrum to the Structure of Quantum Gravity. (arXiv:2011.08707v1 [hep-th])

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Yasunori Nomura

We portray the structure of quantum gravity emerging from recent progress in understanding the quantum mechanics of an evaporating black hole. Quantum gravity admits two different descriptions, based on Euclidean gravitational path integral and a unitarily evolving holographic quantum system, which appear to present vastly different pictures under the existence of a black hole. Nevertheless, these two descriptions are physically equivalent. Various issues of black hole physics—including the existence of the interior, unitarity of the evolution, the puzzle of too large interior volume, and the ensemble nature seen in certain calculations—are addressed very differently in the two descriptions, still leading to the same physical conclusions. The perspective of quantum gravity developed here is expected to have broader implications beyond black hole physics, especially for the cosmology of the eternally inflating multiverse.

Models of Discrete Linear Evolution for Quantum Systems. (arXiv:2011.08715v1 [gr-qc])

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Jakub Káninský

Discrete canonical evolution is a key tool for understanding the dynamics in discrete models of spacetime, in particular those represented by a triangular Regge lattice. We consider a finite-dimensional system whose evolution is realized by a series of discrete-time evolution steps governed by Hamiltonian equations of motion that are linear in the canonical coordinates. The evolution is allowed to be irregular, which produces constraints as well as non-uniqueness of solutions. We provide two independent and fundamentally different approaches to canonical quantization of this system, including detailed description of the evolution maps, measurement and path integrals. It is argued that some irregular discrete systems may be most naturally described by a non-unitary quantum evolution. The formalism is then applied to a simple yet physically relevant model of massless scalar field on a two-dimensional spacetime lattice.

Testing and Emulating Modified Gravity on Cosmological Scales. (arXiv:2011.08786v1 [astro-ph.CO])

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Andrius Tamosiunas

This thesis introduces a set of methods for testing models of modified gravity using galaxy clusters. In particular, a technique for constraining models with a chameleon screening is introduced. In addition, the outlined technique is expanded to test a wider class of models, such as the theory of emergent gravity. Finally, the first part of the thesis is concluded by adapting the mentioned tests for model independent constraints. The obtained results indicate that galaxy clusters can be used to obtain some of the most powerful constraints on cosmological scales.

The second part of the thesis is dedicated to the topic of cosmological emulators. More specifically, a technique of emulating cosmological N-body simulation output data based on machine learning is introduced. Generative adversarial networks (GANs) are used to emulate dark matter-only as well as hydrodynamical simulation data. In addition, N-body modified gravity simulations are explored as well. The presented investigation of the GAN algorithm shows that such emulators offer a powerful, fast and efficient way of producing simulation output data with different cosmological parameters. The power spectrum analysis indicates a 1-20% difference between the training and the generated data depending on the dataset used and whether Gaussian smoothing is applied or not.

上午8:59 | | | gr-qc updates on arXiv.org |

Authors: Wilfried Buchmuller, Valerie Domcke, Hitoshi Murayama, Kai Schmitz

The spontaneous breaking of U(1)_B-L around the scale of grand unification can simultaneously account for hybrid inflation, leptogenesis, and neutralino dark matter, thus resolving three major puzzles of particle physics and cosmology in a single predictive framework. The B-L phase transition also results in a network of cosmic strings. If strong and electroweak interactions are unified in an SO(10) gauge group, containing U(1)_B-L as a subgroup, these strings are metastable. In this case, they produce a stochastic background of gravitational waves that evades current pulsar timing bounds, but features a flat spectrum with amplitude h^2\Omega_GW ~ 10^-8 at interferometer frequencies. Ongoing and future LIGO observations will hence probe the scale of B-L breaking.

On how Epistemological Letters changed the foundations of quantum mechanics

上午3:06 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Murgueitio Ramírez, Sebastián (2020) On how Epistemological Letters changed the foundations of quantum mechanics. [Preprint]

Free Will and the Cross-Level Consequence Argument

2020年11月18日 星期三 下午1:36 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Birch, Jonathan (2020) Free Will and the Cross-Level Consequence Argument. [Preprint]

Structural Realism and Generative Grammar

2020年11月18日 星期三 下午1:35 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Nefdt, Ryan M. (2020) Structural Realism and Generative Grammar. [Preprint]

2020年11月17日 星期二 上午9:53 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Cocco, Lorenzo (2020) The ontology of a theory. [Preprint]

No relation for Wigner’s friend

2020年11月17日 星期二 上午9:50 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Castellani, Leonardo (2020) No relation for Wigner’s friend. [Preprint]

Three noncontextual hidden variable models for the Peres-Mermin square

2020年11月17日 星期二 上午9:49 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gábor, Hofer-Szabó (2020) Three noncontextual hidden variable models for the Peres-Mermin square. [Preprint]

Constitutive Elements Through Perspectival Lenses

2020年11月17日 星期二 上午4:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Sanjuán, Mariano (2020) Constitutive Elements Through Perspectival Lenses. [Preprint]

Hamilton, Hamiltonian Mechanics, and Causation

2020年11月17日 星期二 上午4:00 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Weaver, Christopher (2020) Hamilton, Hamiltonian Mechanics, and Causation. [Preprint]

How uncertainty can save measurement from circularity and holism

2020年11月17日 星期二 上午3:57 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Ritson, Sophie and Staley, Kent (2020) How uncertainty can save measurement from circularity and holism. Studies in History and Philosophy of Science Part A. ISSN 00393681

Minimizing Backaction through Entangled Measurements

2020年11月16日 星期一 下午6:00 | | | Kang-Da Wu, Elisa Bäumer, Jun-Feng Tang, Karen V. Hovhannisyan, Martí Perarnau-Llobet, Guo-Yong Xiang, Chuan-Feng Li, and Guang-Can Guo | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Kang-Da Wu, Elisa Bäumer, Jun-Feng Tang, Karen V. Hovhannisyan, Martí Perarnau-Llobet, Guo-Yong Xiang, Chuan-Feng Li, and Guang-Can Guo

When an observable is measured on an evolving coherent quantum system twice, the first measurement generally alters the statistics of the second one, which is known as measurement backaction. We introduce, and push to its theoretical and experimental limits, a novel method of backaction evasion, whe…

[Phys. Rev. Lett. 125, 210401] Published Mon Nov 16, 2020

2020年11月16日 星期一 上午8:00 | | | Laura Cattaneo | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 16 November 2020; doi:10.1038/s41567-020-01080-4

When molecular model systems, such as polycyclic aromatic hydrocarbons, are ionized by ultrashort extreme ultraviolet pulses, their relaxation path proceeds via electron–phonon scattering, linking molecules to typical solid-state matter behaviour.

2020年11月16日 星期一 上午8:00 | | | Latest Results for Synthese |

**Abstract**

I critically discuss two dogmas of the “dynamical approach” to spacetime in general relativity, as advanced by Harvey Brown [*Physical Relativity* (2005) Oxford:Oxford University Press] and collaborators. The first dogma is that positing a “spacetime geometry” has no implications for the behavior of matter. The second dogma is that postulating the “Strong Equivalence Principle” suffices to ensure that matter is “adapted” to spacetime geometry. I conclude by discussing “spacetime functionalism”. The discussion is presented in reaction to and sympathy with recent work by James Read [“Explanation, geometry, and conspiracy in relativity theory” (2020) *Thinking about Spacetime* Boston: Birkäuser].

2020年11月15日 星期日 下午6:28 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Mantzavinos, C. (2013) Explanatory Games. The Journal of Philosophy, CX. pp. 606-632. ISSN 0022-362X

]]>上午9:32 | | | Jonathan Oppenheim, Carlo Sparaciari, Barbara Šoda, Zachary Weller-Davies | | | quant-ph updates on arXiv.org |

Consistent dynamics which couples classical and quantum degrees of freedom exists, provided it is stochastic. This provides a way to study the back-reaction of quantum fields on space-time which does not suffer from the pathologies of the semi-classical equations. Here we introduce several toy models in which to study hybrid classical-quantum evolution, including a qubit coupled to a particle in a potential, and a quantum harmonic oscillator coupled to a classical one. We present an unravelling approach to calculate the dynamics. Unlike the purely quantum case, the trajectories (or histories) of this unravelling can be unique, conditioned on the classical degrees of freedom. This provides a potential solution to the “measurement problem” of quantum theory; quantum systems become classical because they interact with a genuinely classical field.

An Argument for Strong Positivity of the Decoherence Functional. (arXiv:2011.06120v1 [quant-ph])

上午9:32 | | | Fay Dowker, Henry Wilkes | | | quant-ph updates on arXiv.org |

We give an argument for strong positivity of the decoherence functional as the correct, physical positivity condition in formulations of quantum theory based fundamentally on the path integral. We extend to infinite systems work by Boes and Navascues that shows that the set of strongly positive quantum systems is maximal amongst sets of systems that are closed under tensor product composition. We show further that the set of strongly positive quantum systems is the unique set that is maximal amongst sets that are closed under tensor product composition.

Prospects and challenges of quantum finance. (arXiv:2011.06492v1 [q-fin.CP])

上午9:32 | | | Adam Bouland, Wim van Dam, Hamed Joorati, Iordanis Kerenidis, Anupam Prakash | | | quant-ph updates on arXiv.org |

Quantum computers are expected to have substantial impact on the finance industry, as they will be able to solve certain problems considerably faster than the best known classical algorithms. In this article we describe such potential applications of quantum computing to finance, starting with the state-of-the-art and focusing in particular on recent works by the QC Ware team. We consider quantum speedups for Monte Carlo methods, portfolio optimization, and machine learning. For each application we describe the extent of quantum speedup possible and estimate the quantum resources required to achieve a practical speedup. The near-term relevance of these quantum finance algorithms varies widely across applications – some of them are heuristic algorithms designed to be amenable to near-term prototype quantum computers, while others are proven speedups which require larger-scale quantum computers to implement. We also describe powerful ways to bring these speedups closer to experimental feasibility – in particular describing lower depth algorithms for Monte Carlo methods and quantum machine learning, as well as quantum annealing heuristics for portfolio optimization. This article is targeted at financial professionals and no particular background in quantum computation is assumed.

上午9:32 | | | Andreas Bluhm, Anna Jenčová, Ion Nechita | | | quant-ph updates on arXiv.org |

In this work, we investigate measurement incompatibility in general probabilistic theories (GPTs). We show several equivalent characterizations of compatible measurements. The first is in terms of the positivity of associated maps. The second relates compatibility to the inclusion of certain generalized spectrahedra. For this, we extend the theory of free spectrahedra to ordered vector spaces. The third characterization connects the compatibility of dichotomic measurements to the ratio of tensor crossnorms of Banach spaces. We use these characterizations to study the amount of incompatibility present in different GPTs, i.e. their compatibility regions. For centrally symmetric GPTs, we show that the compatibility degree is given as the ratio of the injective and the projective norm of the tensor product of associated Banach spaces. This allows us to completely characterize the compatibility regions of several GPTs, and to obtain optimal universal bounds on the compatibility degree in terms of the 1-summing constants of the associated Banach spaces. Moreover, we find new bounds on the maximal incompatibility present in more than three qubit measurements.

上午9:32 | | | Gábor Hofer-Szabó | | | quant-ph updates on arXiv.org |

I will argue that the Peres-Mermin square does not necessarily rule out a value-definite (deterministic) noncontextual hidden variable model if the operators are not given a physical interpretation satisfying the following two requirements: (i) each operator is uniquely realized by a single physical measurement; (ii) commuting operators are realized by simultaneous measurements. To underpin this claim, I will construct three hidden variable models for three different physical realizations of the Peres-Mermin square: one violating (i), another violating (ii), and a third one violating both (i) and (ii).

Toward simulating Superstring/M-theory on a quantum computer. (arXiv:2011.06573v1 [hep-th])

上午9:32 | | | Hrant Gharibyan, Masanori Hanada, Masazumi Honda, Junyu Liu | | | quant-ph updates on arXiv.org |

We present a novel framework for simulating matrix models on a quantum computer. Supersymmetric matrix models have natural applications to superstring/M-theory and gravitational physics, in an appropriate limit of parameters. Furthermore, for certain states in the Berenstein-Maldacena-Nastase (BMN) matrix model, several supersymmetric quantum field theories dual to superstring/M-theory can be realized on a quantum device. Our prescription consists of four steps: regularization of the Hilbert space, adiabatic state preparation, simulation of real-time dynamics, and measurements. Regularization is performed for the BMN matrix model with the introduction of energy cut-off via the truncation in the Fock space. We use the Wan-Kim algorithm for fast digital adiabatic state preparation to prepare the low-energy eigenstates of this model as well as thermofield double state. Then, we provide an explicit construction for simulating real-time dynamics utilizing techniques of block-encoding, qubitization, and quantum signal processing. Lastly, we present a set of measurements and experiments that can be carried out on a quantum computer to further our understanding of superstring/M-theory beyond analytic results.

Combined Lorentz symmetry. (arXiv:2011.06466v1 [gr-qc])

上午9:32 | | | gr-qc updates on arXiv.org |

Authors: G.E. Volovik

This is the comment to the paper by S.N. Vergeles, A note on the vacuum structure of lattice Euclidean quantum gravity: birth of macroscopic space-time and $PT$-symmetry breaking, arXiv:1903.09957, where the gravitational tetrads are considered as the order parameter of the symmetry breaking in the quantum vacuum. We discuss some consequences of this approach.

Emergence of classical behavior in the early universe. (arXiv:2004.10684v3 [gr-qc] UPDATED)

上午9:32 | | | gr-qc updates on arXiv.org |

Authors: Abhay Ashtekar, Alejandro Corichi, Aruna Kesavan

We investigate three issues that have been discussed in the context of inflation: Fading of the importance of quantum non-commutativity; the phenomenon of quantum squeezing; and the ability to approximate the quantum state by a distribution function on the classical phase space. In the standard treatments, these features arise from properties of mode functions of quantum fields in (near) de Sitter space-time. Therefore, the three notions are often assumed to be essentially equivalent, representing different facets of the same phenomenon. We analyze them in general Friedmann-Lemaitre- Robertson-Walker space-times, through the lens of geometric structures on the classical phase space. The analysis shows that: (i) inflation does not play an essential role; classical behavior can emerge much more generally; (ii) the three notions are conceptually distinct; classicality can emerge in one sense but not in another; and, (iii) the third notion is realized in a surprisingly strong sense; there is exact equality between completely general $n$-point functions in the classical theory and those in the quantum theory, provided the quantum operators are Weyl ordered. These features arise already for linear cosmological perturbations by themselves: considerations such as mode-mode coupling, decoherence, and measurement theory –although important in their own right– are not needed for emergence of classical behavior in any of the three senses discussed. Generality of the results stems from the fact that they can be traced back to geometrical structures on the classical phase space, available in a wide class of systems. Therefore, this approach may also be useful in other contexts.

Separating Einstein’s separability

上午9:32 | | | ScienceDirect Publication: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsScienceDirect RSShttps://www.sciencedirect.com/journal/studies-in-history-and-philosophy-of-science-part-b-studies-in-history-and-philosophy-of-modern-physicsRSS for NodeWed, 24 Jul 2019 09:46:42 GMTCopyright © 2019 Elsevier Ltd. All rights reservedImprints of the underlying structure of physical theoriesPublication date: Available online 12 July 2019Source: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsAuthor(s): Jorge ManeroAbstractIn the context of scientific realism, this paper intends to provide a formal and accurate description of the structural-based ontology posited by classical mechanics, quantum mechanics and special relativity, which is preserved across the empirical domains of these theories and explain their successful predictions. Along the lines of ontic structural realism, such a description is undertaken by |

Publication date: Available online 12 November 2020

**Source:** Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics

Author(s): Sebastián Murgueitio Ramírez

Observing Localization in a 2D Quasicrystalline Optical Lattice

2020年11月13日 星期五 下午6:00 | | | Matteo Sbroscia, Konrad Viebahn, Edward Carter, Jr-Chiun Yu, Alexander Gaunt, and Ulrich Schneider | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Matteo Sbroscia, Konrad Viebahn, Edward Carter, Jr-Chiun Yu, Alexander Gaunt, and Ulrich Schneider

Quasicrystals are long-range ordered but not periodic, representing an interesting middle ground between order and disorder. We experimentally and numerically study the localization transition in the ground state of noninteracting and weakly interacting bosons in an eightfold symmetric quasicrystall…

[Phys. Rev. Lett. 125, 200604] Published Fri Nov 13, 2020

2020年11月13日 星期五 下午5:55 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Glauer, Ramiro and Hildebrandt, Frauke (2020) No facts without perspectives. [Preprint]

On the Imprecision of Full Conditional Probabilities

2020年11月13日 星期五 下午5:53 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wheeler, Gregory and Cozman, Fabio (2020) On the Imprecision of Full Conditional Probabilities. [Preprint]

Credence—and Chance—Without Numbers (and with the Euclidean Property)

2020年11月11日 星期三 下午6:07 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Maudlin, Tim (2020) Credence—and Chance—Without Numbers (and with the Euclidean Property). [Preprint]

The Problem of Molecular Structure Just Is The Measurement Problem

2020年11月11日 星期三 下午6:06 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Franklin, Alexander and Seifert, Vanessa A. (2020) The Problem of Molecular Structure Just Is The Measurement Problem. The British Journal for the Philosophy of Science. ISSN 1464-3537

An Assumption in the Interpretation of Quantum Mechanics

2020年11月11日 星期三 下午6:05 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Price, Huw (1978) An Assumption in the Interpretation of Quantum Mechanics. [Preprint]

2020年11月11日 星期三 下午6:04 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hirèche, Salim and Linnemann, Niels and Michels, Robert and Vogt, Lisa (2020) The modal status of the laws of nature. Tahko’s hybrid view and the kinematical/dynamical distinction. [Preprint]

2020年11月11日 星期三 下午6:03 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Glick, David (2020) Book Review: French, S., & Saatsi, J. (Eds.). (2020). Scientific Realism and the Quantum. Oxford University Press. [Preprint]

Indeterminism in Physics and Intuitionistic Mathematics

2020年11月10日 星期二 上午6:14 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gisin, Nicolas (2020) Indeterminism in Physics and Intuitionistic Mathematics. [Preprint]

Correction to: Fundamental mentality in a physical world

2020年11月9日 星期一 上午8:00 | | | Latest Results for Synthese |

The original article has been corrected.

How (not) to judge a theory of causation

2020年11月9日 星期一 上午8:00 | | | Latest Results for Synthese |

**Abstract**

Philosophical theories of causation are commonly judged by their ability to correctly determine whether there is a causal relation present in intuitively clear example scenarios. If the theories survive this test, they are then used to answer big philosophical questions about causation. This Method of Examples is attractive because it seems to allow us to determine the quality of a theory of causation independently of answering the big philosophical questions; which is good, since it means that we can then non-circularly use the theories judged to be best to answer those questions. However, the current article argues that this virtue of the Method of Examples is an illusion. In particular, I argue that the necessary step of judging whether a proposed analysis of causation is reductive can only be taken after many of the most vexing philosophical questions about causation have already been answered. It is then shown that a rejection of the methodological supremacy of the Method of Examples leads to a more pluralistic method of judging theories of causation, a pluralism that benefits non-standard approaches like interventionism and agency theories.

The substantial role of Weyl symmetry in deriving general relativity from string theory

2020年11月9日 星期一 上午4:18 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Dougherty, John (2020) The substantial role of Weyl symmetry in deriving general relativity from string theory. In: UNSPECIFIED.

Clarifying the New Problem for Quantum Mechanics: Reply to Vaidman

2020年11月9日 星期一 上午4:15 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Meehan, Alexander (2020) Clarifying the New Problem for Quantum Mechanics: Reply to Vaidman. [Preprint]

Quantum Physics in Non-Separable Hilbert Spaces

2020年11月9日 星期一 上午4:12 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Earman, John S (2020) Quantum Physics in Non-Separable Hilbert Spaces. [Preprint]

Absolute Velocities Are Unmeasurable: Response to Middleton and Murgueitio Ramírez

2020年11月9日 星期一 上午4:11 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Jacobs, Caspar (2020) Absolute Velocities Are Unmeasurable: Response to Middleton and Murgueitio Ramírez. [Preprint]

]]>上午10:08 | | | Zong-Gang Mou, Peter Millington, Paul M. Saffin, Anders Tranberg | | | quant-ph updates on arXiv.org |

Inspired by Lefschetz thimble theory, we treat Quantum Field Theory as a statistical theory with a complex Probability Distribution Function (PDF). Such complex-valued PDFs permit the violation of Bell-type inequalities, which cannot be violated by a real-valued, non-negative PDF. In this paper, we consider the Classical-Statistical approximation in the context of Bell-type inequalities, viz. the familiar (spatial) Bell inequalities and the temporal Leggett-Garg inequalities. We show that the Classical-Statistical approximation does not violate temporal Bell-type inequalities, even though it is in some sense exact for a free theory, whereas the full quantum theory does. We explain the origin of this discrepancy, and point out the key difference between the spatial and temporal Bell-type inequalities. We comment on the import of this work for applications of the Classical-Statistical approximation.

The probabilistic world. (arXiv:2011.02867v1 [quant-ph])

上午10:08 | | | C. Wetterich | | | quant-ph updates on arXiv.org |

This work attempts a fundamental formulation of physics based on probabilities. The basic assumptions are simple: One world exists. Humans can understand its properties by formulating laws based on probabilities. Our probabilistic setting only employs the notions of a probability distribution, observables and their expectation values, which are computed according to the classical statistical rule. Time is an ordering structure among observables. Understanding the probabilistic laws enables humans to make predictions for future events. Also space, spacetime and geometry emerge as structures among observables.

Within the classical statistical system the time structure induces the concepts of wave functions, density matrices, non-commuting operators and many other aspects of quantum physics. The classical density matrix encodes the probabilistic information of a time-local subsystem. Subsystems are typically correlated with their environment, offering a much richer structure than discussed commonly. We pay particular attention to subsystems with incomplete statistics and probabilistic observables.

Quantum systems are particular time-local subsystems that follow an unitary evolution law. All laws of quantum mechanics are derived from the basic law for expectation values in classical statistics. In particular, we discuss entangled quantum systems in terms of classical probability distributions. In our approach quantum field theories have to be described by an overall probability distribution for the whole Universe for all times. The fundamental functional integral for quantum field theories should define a probability distribution, underlying the functional integral with Minkowski signature.

While this work remains in the context of theoretical physics, the concepts developed here apply to a wide area of science.

Bekenstein bound from the Pauli principle. (arXiv:2005.13973v2 [hep-th] UPDATED)

上午10:08 | | | Giovanni Acquaviva, Alfredo Iorio, Luca Smaldone | | | quant-ph updates on arXiv.org |

Assuming that the degrees of freedom of a black hole are finite in number and of fermionic nature, we naturally obtain, within a second-quantized toy model of the evaporation, that the Bekenstein bound is a consequence of the Pauli exclusion principle for these fundamental degrees of freedom. We show that entanglement, Bekenstein and thermodynamic entropies of the black hole all stem from the same approach, based on the entropy operator whose structure is the one typical of Takahashi and Umezawa’s Thermofield Dynamics. We then evaluate the von Neumann black hole–environment entropy and noticeably obtain a Page-like evolution. We finally show that this is a consequence of a duality between our model and a quantum dissipative-like fermionic system.

The Heisenberg limit for laser coherence. (arXiv:2009.05296v2 [quant-ph] UPDATED)

上午10:08 | | | Travis J. Baker, S. N. Saadatmand, Dominic W. Berry, Howard M. Wiseman | | | quant-ph updates on arXiv.org |

To quantify quantum optical coherence requires both the particle- and wave-natures of light. For an ideal laser beam [1,2,3], it can be thought of roughly as the number of photons emitted consecutively into the beam with the same phase. This number, $\mathfrak{C}$, can be much larger than $\mu$, the number of photons in the laser itself. The limit on $\mathfrak{C}$ for an ideal laser was thought to be of order $\mu^2$ [4,5]. Here, assuming nothing about the laser operation, only that it produces a beam with certain properties close to those of an ideal laser beam, and that it does not have external sources of coherence, we derive an upper bound: $\mathfrak{C} = O(\mu^4)$. Moreover, using the matrix product states (MPSs) method [6,7,8,9], we find a model that achieves this scaling, and show that it could in principle be realised using circuit quantum electrodynamics (QED) [10]. Thus $\mathfrak{C} = O(\mu^2)$ is only a standard quantum limit (SQL); the ultimate quantum limit, or Heisenberg limit, is quadratically better.

Incompleteness for stably sound Turing machines. (arXiv:2001.07592v5 [cs.LO] UPDATED)

上午10:08 | | | physics.hist-ph updates on arXiv.org |

Authors: Yasha Savelyev

We first partly develop a mathematical notion of stable soundness intended to reflect the actual soundness property of human beings. Then we show that given an abstract query machine $M$ (a function) the following cannot hold simultaneously: $M$ is stably sound, $M$ is computable, $M$ can decide the truth of any arithmetic statement. This can be understood as an extension of the G\”odel incompleteness theorem to stably sound setting. This is a non-trivial extension as a stably sound Turing machine can decide the halting problem. In practice such an $M$ could be meant to represent a weakly idealized human being so that the above gives an obstruction to computability of intelligence, and this gives a formal extension of a famous disjunction of G\”odel.

Loop quantum gravity, signature change, and the no-boundary proposal. (arXiv:2011.02884v1 [gr-qc])

上午10:08 | | | gr-qc updates on arXiv.org |

Authors: Martin Bojowald, Suddhasattwa Brahma

Covariant models of loop quantum gravity generically imply dynamical signature change at high density. This article presents detailed derivations that show the fruitful interplay of this new kind of signature change with wave-function proposals of quantum cosmology, such as the no-boundary and tunneling proposals. In particular, instabilities of inhomogeneous perturbations found in a Lorentzian path-integral treatment are naturally cured. Importantly, dynamical signature change does not require Planckian densities when off-shell instantons are relevant.

Testing General Relativity with Gravitational Waves. (arXiv:2011.02938v1 [gr-qc])

上午10:08 | | | gr-qc updates on arXiv.org |

Authors: Zack Carson, Kent Yagi

Gravitational-wave sources offer us unique testbeds for probing strong-field, dynamical and nonlinear aspects of gravity. In this chapter, we give a brief overview of the current status and future prospects of testing General Relativity with gravitational waves. In particular, we focus on three theory-agnostic tests (parameterized tests, inspiral-merger-ringdown consistency tests, and gravitational-wave propagation tests) and explain how one can apply such tests to example modified theories of gravity. We conclude by giving some open questions that need to be resolved to carry out more accurate tests of gravity with gravitational waves.

上午10:08 | | | ScienceDirect Publication: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsScienceDirect RSShttps://www.sciencedirect.com/journal/studies-in-history-and-philosophy-of-science-part-b-studies-in-history-and-philosophy-of-modern-physicsRSS for NodeWed, 24 Jul 2019 09:46:42 GMTCopyright © 2019 Elsevier Ltd. All rights reservedImprints of the underlying structure of physical theoriesPublication date: Available online 12 July 2019Source: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsAuthor(s): Jorge ManeroAbstractIn the context of scientific realism, this paper intends to provide a formal and accurate description of the structural-based ontology posited by classical mechanics, quantum mechanics and special relativity, which is preserved across the empirical domains of these theories and explain their successful predictions. Along the lines of ontic structural realism, such a description is undertaken by |

Publication date: Available online 3 November 2020

**Source:** Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics

Author(s): Niels C.M. Martens, Dennis Lehmkuhl

Completely real? A critical note on the claims by Colbeck and Renner

上午10:08 | | | ScienceDirect Publication: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsScienceDirect RSShttps://www.sciencedirect.com/journal/studies-in-history-and-philosophy-of-science-part-b-studies-in-history-and-philosophy-of-modern-physicsRSS for NodeWed, 24 Jul 2019 09:46:42 GMTCopyright © 2019 Elsevier Ltd. All rights reservedImprints of the underlying structure of physical theoriesPublication date: Available online 12 July 2019Source: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsAuthor(s): Jorge ManeroAbstractIn the context of scientific realism, this paper intends to provide a formal and accurate description of the structural-based ontology posited by classical mechanics, quantum mechanics and special relativity, which is preserved across the empirical domains of these theories and explain their successful predictions. Along the lines of ontic structural realism, such a description is undertaken by |

Publication date: Available online 2 November 2020

**Source:** Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics

Author(s): R. Hermens

Angular momentum without rotation: turbocharging relationalism

2020年11月5日 星期四 上午2:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gomes, Henrique and Gryb, Sean (2020) Angular momentum without rotation: turbocharging relationalism. [Preprint]

Absolute Velocities Are Unmeasurable: Response to Middleton and Murgueitio Ramírez

2020年11月5日 星期四 上午2:32 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Jacobs, Caspar (2020) Absolute Velocities Are Unmeasurable: Response to Middleton and Murgueitio Ramírez. [Preprint]

The force of perpetual problems

2020年11月4日 星期三 上午8:00 | | | Mark Buchanan | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 04 November 2020; doi:10.1038/s41567-020-01099-7

The force of perpetual problems

The Influence of Quantum Physics on Philosophy

2020年11月3日 星期二 下午1:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Muller, F.A. (2020) The Influence of Quantum Physics on Philosophy. [Preprint]

2020年11月3日 星期二 下午1:22 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Giovanelli, Marco (2020) Like Thermodynamics before Boltzmann. On the Emergence of Einstein’s Distinction between Constructive and Principle Theories. [Preprint]

A Puzzle for the Field Ontologists

2020年11月3日 星期二 下午1:20 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2020) A Puzzle for the Field Ontologists. Foundations of Physics.

Understanding and Equivalent Reformulations

2020年11月3日 星期二 下午1:19 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hunt, Josh (2020) Understanding and Equivalent Reformulations. In: UNSPECIFIED.

2020年11月3日 星期二 下午1:19 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Oldofredi, Andrea and Öttinger, Hans Christian (2020) The Dissipative Approach to Quantum Field Theory: Conceptual Foundations and Ontological Implications. [Preprint]

2020年11月3日 星期二 下午1:17 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Rodolfo, Gambini and Jorge, Pullin (2020) The Montevideo Interpretation: How the inclusion of a Quantum Gravitational Notion of Time Solves the Measurement Problem. [Preprint]

A physical interpretation of Lewis’ discrepancy between personal and external time in time travels

2020年11月1日 星期日 上午8:00 | | | Latest Results for Synthese |

**Abstract**

This paper deals with those time travels mostly considered by physics, namely those in the form of the so-called closed timelike curves. Some authoritative scholars have raised doubts about the status of these journeys as proper time travels. By using David Lewis’ famous definition of time travels proposed in 1976, we show that this proper status may actually be recovered, at least in some cosmological contexts containing spacetime regions, such as those concerning black holes described by the Kerr–Newman metric, that allow the formation of local closed curves. But, the mathematical incompatibility between ordinary black hole solutions to Einstein field equations and the cosmological solutions induces us to take into consideration the more general issue pertaining to the slippery interplay between models related to local and global aspects of the world, highlighting, in particular, the different notions of time that these domains inevitably imply. This leads us to think that time is not a univocal entity of the world, but is a scale-related characteristic which claims the adoption, when investigating its ontological status, of a sort of regional approach. We also briefly dwell upon the most appropriate form of realism that such a kind of dispute between local and global models may involve.

Geometrodynamics as Functionalism about Time

2020年11月1日 星期日 上午3:44 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gomes, Henrique and Butterfield, Jeremy (2020) Geometrodynamics as Functionalism about Time. [Preprint]

]]>上午10:31 | | | T. Mart | | | quant-ph updates on arXiv.org |

In this paper I explain how I usually introduce the Schr\”odinger equation during the quantum mechanics course. My preferred method is the chronological one. Since the Schr\”odinger equation belongs to a special case of wave equations I start the course with introducing the wave equation. The Schr\”odinger equation is derived with the help of the two quantum concepts introduced by Max Planck, Einstein, and de Broglie, i.e., the energy of a photon $E=\hbar\omega$ and the wavelength of the de Broglie wave $\lambda=h/p$. Finally, the difference between the classical wave equation and the quantum Schr\”odinger one is explained in order to help the students to grasp the meaning of quantum wavefunction $\Psi({\bf r},t)$. A comparison of the present method to the approaches given by the authors of quantum mechanics textbooks as well as that of the original Nuffield A level is presented. It is found that the present approach is different from those given by these authors, except by Weinberg or Dicke and Wittke. However, the approach is in line with the original Nuffield A level one.

Multipath Wave Particle Duality with a Spooky Path Detector. (arXiv:2010.15719v1 [quant-ph])

上午10:31 | | | Mohd Asad Siddiqui, Tabish Qureshi | | | quant-ph updates on arXiv.org |

According to Bohr’s principle of complementarity, a quanton can behave either as a wave or a particle, depending on the choice of the experimental setup. Some recent two-path interference experiments have devised methods where one can have a quantum superposition of the two choices, thus indicating that a quanton may be in a superposition of wave and particle nature. These experiments have been of interest from the point of view of Wheeler’s delayed-choice experiment. However, it has also been claimed that this experiment can violate complementarity. Here we theoretically analyze a multipath interference experiment that has a which-path detector in a quantum superposition of being present and absent. We show that a tight multipath wave-particle duality relation is respected in all such situations, and complementarity holds good. The apparent violation of complementarity may be due to incorrect evaluation of path distinguishability in such scenarios.

上午10:31 | | | Marijn Waaijer, Jan van Neerven | | | quant-ph updates on arXiv.org |

We present an analysis of the Frauchiger–Renner Gedankenexperiment from the point of view of the relational interpretation of quantum mechanics. Our analysis indicates that the paradox obtained by Frauchiger and Renner arises from reasoning about other agent’s knowledge in the past without validation by surviving records. A by-product of our analysis is an interaction-free detection scheme for the existence of records from the past.

上午10:31 | | | physics.hist-ph updates on arXiv.org |

Authors: Robert P. O’Shea (1), Shelby E. Temple (2,3), Gary P. Misson (4,5), Nicholas J. Wade (6), Michael Bach (7,8) ((1) Institute of Psychology–Wilhelm Wundt, University of Leipzig, Leipzig Germany, (2) School of Biological Sciences, University of Bristol, Bristol, UK, (3) Azul Optics Ltd, Bristol, UK, (4) School of Life & Health Sciences, Aston University, Birmingham, UK, (5) Department of Ophthalmology, South Warwickshire NHS Foundation Trust, Warwick, UK, (6) Psychology, University of Dundee, Dundee, UK, (7) University Eye Center, Medical Center, University of Freiburg, Freiburg, Germany, (8) Faculty of Medicine, University of Freiburg, Freiburg, Germany)

In 1844, the Austrian mineralogist Wilhelm von Haidinger reported he could see the polarization of light with the naked eye. It appears as a faint, blurry, transient, yellow hourglass shape superimposed on whatever one looks at. It is now commonly called Haidinger’s brushes. To our surprise, even though the paper is well cited, we were unable to find a translation of it from its difficult, nineteenth-century German into English. We provide one, with annotations to set the paper into its scientific and historical context.

上午10:31 | | | physics.hist-ph updates on arXiv.org |

Authors: Luisa Bonolis, Juan-Andres Leon

On the occasion of the 50th anniversary since the beginning of the search for gravitational waves at the Max Planck Society, and in coincidence with the 25th anniversary of the foundation of the Albert Einstein Institute, we explore the interplay between the renaissance of general relativity and the advent of relativistic astrophysics following the German early involvement in gravitational-wave research, to the point when gravitational-wave detection became established by the appearance of full-scale detectors and international collaborations. On the background of the spectacular astrophysical discoveries of the 1960s and the growing role of relativistic astrophysics, Ludwig Biermann and his collaborators at the Max Planck Institute for Astrophysics in Munich became deeply involved in research related to such new horizons. At the end of the 1960s, Joseph Weber’s announcements claiming detection of gravitational waves sparked the decisive entry of this group into the field, in parallel with the appointment of the renowned relativist Juergen Ehlers. The Munich area group of Max Planck institutes provided the fertile ground for acquiring a leading position in the 1970s, facilitating the experimental transition from resonant bars towards laser interferometry and its innovation at increasingly large scales, eventually moving to a dedicated site in Hannover in the early 1990s. The Hannover group emphasized perfecting experimental systems at pilot scales, and never developed a full-sized detector, rather joining the LIGO Scientific Collaboration at the end of the century. In parallel, the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) had been founded in Potsdam, and both sites, in Hannover and Potsdam, became a unified entity in the early 2000s and were central contributors to the first detection of gravitational waves in 2015.

上午10:31 | | | gr-qc updates on arXiv.org |

Authors: Shahab Joudaki, Pedro G. Ferreira, Nelson A. Lima, Hans A. Winther

We provide an end-to-end exploration of a distinct modified gravitational theory in Jordan-Brans-Dicke (JBD) gravity, from an analytical and numerical description of the background expansion and linear perturbations, to the nonlinear regime captured with a hybrid suite of $N$-body simulations, to the parameter constraints from existing cosmological probes. The nonlinear corrections to the matter power spectrum due to baryons, massive neutrinos, and modified gravity are simultaneously modeled and propagated in the cosmological analysis for the first time. In the combined analysis of the Planck CMB temperature, polarization, and lensing reconstruction, Pantheon supernova distances, BOSS measurements of BAO distances, the Alcock-Paczynski effect, and the growth rate, along with the joint ($3\times2$pt) dataset of cosmic shear, galaxy-galaxy lensing, and overlapping redshift-space galaxy clustering from KiDS and 2dFLenS, we constrain the JBD coupling constant, $\omega_{\rm BD}>1540$ (95% CL), the effective gravitational constant, $G_{\rm matter}/G=0.997\pm0.029$, the sum of neutrino masses, $\sum m_{\nu}<0.12$ eV (95% CL), and the baryonic feedback amplitude, $B<2.8$ (95% CL), all in agreement with the standard model expectation. We show that the uncertainty in the gravitational theory alleviates the tension between KiDS$\times$2dFLenS and Planck to below $1\sigma$ and the tension in the Hubble constant between Planck and the direct measurement of Riess et al. (2019) down to ~$3\sigma$; however, we find no substantial model selection preference for JBD gravity relative to $\Lambda$CDM. We further show that the neutrino mass bound degrades by up to a factor of $3$ as the $\omega_{\rm BD}$ parameterization becomes more restrictive, and that a positive shift in $G_{\rm matter}/G$ suppresses the CMB damping tail in a way that might complicate future inferences of small-scale physics. (Abridged)

2020年10月29日 星期四 下午1:13 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Glick, David (2020) Book Review: French, S., & Saatsi, J. (Eds.). (2020). Scientific Realism and the Quantum. Oxford University Press. [Preprint]

Two Constants in Carnap’s View on Scientific Theories

2020年10月29日 星期四 下午1:05 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Lutz, Sebastian (2020) Two Constants in Carnap’s View on Scientific Theories. [Preprint]

Clock comparison using black holes

2020年10月29日 星期四 上午8:00 | | | Rüdiger Haas | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 29 October 2020; doi:10.1038/s41567-020-01071-5

Observing accreting black holes in the early Universe allows precise comparison of clocks over intercontinental distances on Earth. This is achieved with a novel observation strategy using the next generation of very long baseline interferometry systems.

Measurement of Identical Particle Entanglement and the Influence of Antisymmetrization

2020年10月28日 星期三 下午6:00 | | | J. H. Becher, E. Sindici, R. Klemt, S. Jochim, A. J. Daley, and P. M. Preiss | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): J. H. Becher, E. Sindici, R. Klemt, S. Jochim, A. J. Daley, and P. M. Preiss

We explore the relationship between symmetrization and entanglement through measurements on few-particle systems in a multiwell potential. In particular, considering two or three trapped atoms, we measure and distinguish correlations arising from two different physical origins: antisymmetrization of…

[Phys. Rev. Lett. 125, 180402] Published Wed Oct 28, 2020

Euler’s Königsberg: the explanatory power of mathematics

2020年10月28日 星期三 上午5:45 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Räz, Tim (2017) Euler’s Königsberg: the explanatory power of mathematics. European Journal for Philosophy of Science. ISSN 1879-4912

Stability in Cosmology, from Einstein to Inflation

2020年10月28日 星期三 上午1:45 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

McCoy, C.D. (2020) Stability in Cosmology, from Einstein to Inflation. Thinking About Space and Time. pp. 71-89.

New powers for Dispositionalism

2020年10月27日 星期二 上午8:00 | | | Latest Results for Synthese |

**Abstract**

Establishing Dispositionalism as a viable theory of modality requires the successful fulfilment of two tasks: (i) showing that all modal truths can be derived from truths about actual powers, and (ii) offering a suitable metaphysics of powers. These two tasks are intertwined: difficulties in one can affect the chances of success in the other. In this paper, I generalise an objection to Dispositionalism by Jessica Leech and argue that the theory in its present form is ill-suited to account for de re truths about merely possible entities. I argue that such difficulty is rooted in a problem in the metaphysics of powers. In particular, I contend that the well-known tension between two key principle of powers ontology, namely Directedness (all powers are “for” their manifestation) and Independence (some powers might fail to bring about their manifestation) has received an unsatisfactory solution so far, and that it is this unsatisfactory solution concerning the status of “unmanifested manifestations” that makes it hard for Dispositionalism to account for mere possibilia. I develop a novel account of the status of unmanifested manifestations and an overall metaphysics of powers which allows to better respond to Leech’s objection and handle mere possibilia. The central idea of the proposal is that unmanifested manifestations are akin to mere logical existents, and are best characterised as non-essentially non-located entities.

The Math is not the Territory: Navigating the Free Energy Principle

2020年10月27日 星期二 上午7:23 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Andrews, Mel (2020) The Math is not the Territory: Navigating the Free Energy Principle. [Preprint]

Quantum probability’s algebraic origin

2020年10月26日 星期一 下午3:08 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Niestegge, Gerd (2020) Quantum probability’s algebraic origin. Entropy 2020, 22, 1196. ISSN 1099-4300

The Heisenberg limit for laser coherence

2020年10月26日 星期一 上午8:00 | | | Howard M. Wiseman | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 26 October 2020; doi:10.1038/s41567-020-01049-3

The coherence of a close-to-ideal laser beam can be quadratically better than what was believed to be the quantum limit. This new Heisenberg limit could be attained with circuit quantum electrodynamics.

Bell’s Theorem, Quantum Probabilities, and Superdeterminism

2020年10月25日 星期日 上午7:53 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Chen, Eddy Keming (2020) Bell’s Theorem, Quantum Probabilities, and Superdeterminism. [Preprint]

Opinion: Why science needs philosophy

2020年10月25日 星期日 上午7:49 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Laplane, Lucie and Mantovani, Paolo and Adolphs, Ralph and Chang, Hasok and Mantovani, Alberto and McFall-Ngai, Margaret and Rovelli, Carlo and Sober, Elliott and Pradeu, Thomas (2019) Opinion: Why science needs philosophy. Proceedings of the National Academy of Sciences, 116 (10). pp. 3948-3952. ISSN 0027-8424

]]>2020年10月23日 星期五 下午4:54 | | | Harvey R. Brown, Gal Ben Porath | | | quant-ph updates on arXiv.org |

This paper is concerned with the nature of probability in physics, and in quantum mechanics in particular. It starts with a brief discussion of the evolution of Itamar Pitowsky’s thinking about probability in quantum theory from 1994 to 2008, and the role of Gleason’s 1957 theorem in his derivation of the Born Rule. Pitowsky’s defence of probability therein as a logic of partial belief leads us into a broader discussion of probability in physics, in which the existence of objective “chances” is questioned, and the status of David Lewis’ influential Principal Principle is critically examined. This is followed by a sketch of the work by David Deutsch and David Wallace which resulted in the Deutsch-Wallace (DW) theorem in Everettian quantum mechanics. It is noteworthy that the authors of this important decision-theoretic derivation of the Born Rule have different views concerning the meaning of probability. The theorem, which was the subject of a 2007 critique by Meir Hemmo and Pitowsky, is critically examined, along with recent related work by John Earman. Here our main argument is that the DW theorem does not provide a justification of the Principal Principle, contrary to claims by Wallace and Simon Saunders. A final section analyses recent claims to the effect that that the DW theorem is redundant, a conclusion that seems to be reinforced by consideration of probabilities in “deviant’ branches in the Everettian multiverse.

Quantum State Readout, Collapses, Probes and Signals. (arXiv:2010.11804v1 [quant-ph])

2020年10月23日 星期五 下午4:54 | | | Adrian Kent (Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, and Perimeter Institute for Theoretical Physics) | | | quant-ph updates on arXiv.org |

Theories involving localized collapse allow the possibility that classical information could be obtained about quantum states without using POVMS and without allowing superluminal signalling. We can model this by extending quantum theory to include hypothetical devices that read out information about the local quantum state at a given point, defined by considering only collapses in its past light cone. Like Popescu-Rohrlich boxes, these hypothetical devices would have practical and scientific implications if realisable. These include signalling through opaque media, probing the physics of distant or opaque systems without needing a reflected signal and giving detailed information about collapse dynamics without requiring direct observation of the collapsing system. These potential applications motivate systematic searches for possible signatures of these nonstandard extensions of quantum theory, and in particular for relevant gravitational effects, such as the validity of semi-classical gravity on small scales.

2020年10月23日 星期五 下午4:54 | | | Devashish Pandey, Rui Sampaio, Tapio Ala-Nissila, Guillermo Albareda, Xavier Oriols | | | quant-ph updates on arXiv.org |

The so-called eigenvalue-eigenstate link states that no property can be associated to a quantum system unless it is in an eigenstate of the corresponding operator. This precludes the assignation of properties to unmeasured quantum systems in general. This arbitrary limitation of Orthodox quantum mechanics generates many puzzling situations such as for example the impossibility to define a universal work distribution, an essential building block of quantum thermodynamics. Alternatively, modal theories (e.g., Bohmian mechanics) provide an ontology that is specially suited to define intrinsic properties of general quantum systems that are not in eigensates of the corresponding operators. We prove here that Aharonov, Albert and Vaidman’s weak value can always be identified with intrinsic dynamical property of a quantum system described by a modal theory. Modal (non-Orthodox) theories thus provide a clear-cut physical interpretation of weak values. Furthermore, the fact that weak values are experimentally accessible (to a good approximation as a post-selected ensemble average of weak measurements) strengthens the idea that understanding the intrinsic (unperturbed) dynamics of quantum systems is possible and also useful despite the unavoidable quantum backaction due to the measurement. As an example of the physical soundness of these intrinsic properties, we discuss the Bohmian (intrinsic) dwell time, work distribution and high frequency electrical current.

History entanglement entropy. (arXiv:2009.02331v1 [quant-ph] CROSS LISTED)

2020年10月23日 星期五 下午4:54 | | | physics.hist-ph updates on arXiv.org |

Authors: Leonardo Castellani

A formalism is proposed to describe entangled quantum histories, and their entanglement entropy. We define a history vector, living in a tensor space with basis elements corresponding to the allowed histories, i.e. histories with nonvanishing amplitudes. The amplitudes are the components of the history vector, and contain the dynamical information. Probabilities of measurement sequences, and resulting collapse, are given by generalized Born rules: they are all expressed by means of projections and scalar products involving the history vector. Entangled history states are introduced, and a history density matrix is defined in terms of ensembles of history vectors. The corresponding history entropies (and history entanglement entropies for composite systems) are explicitly computed in two examples taken from quantum computation circuits.

2020年10月23日 星期五 下午4:54 | | |

Publication date: Available online 21 October 2020

**Source:** Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics

Author(s): Howard Stein

Searching for dynamical black holes in various theories of gravity. (arXiv:2010.11790v1 [gr-qc])

2020年10月23日 星期五 下午4:54 | | | gr-qc updates on arXiv.org |

Authors: Shin’ichi Nojiri, Sergei D. Odintsov, Valerio Faraoni

We construct models of Einstein and $f(R)$ gravity with two scalar fields, which admit analytical solutions describing time-varying dynamical black holes. Their thermodynamics is investigated in the adiabatic approximation. In addition to the Misner-Sharp-Hernandez quasilocal mass, we provide time-dependent thermodynamical quantities, including the Hawking temperature, Helmholtz free energy, entropy, and thermodynamical energy. The latter does not always coincide with the Misner-Sharp-Hernandez mass at the horizon, although they coincide in the static limit. For Schwarzschild-type (i.e., $g_{tt}g_{rr}=-1$) black holes in Einstein gravity, one of the two scalars is always a ghost with negative kinetic energy. We show that this ghost can be avoided in $f(R)$ gravity.

Tests of Quantum Gravity near Measurement Events. (arXiv:2010.11811v1 [gr-qc])

2020年10月23日 星期五 下午4:54 | | | gr-qc updates on arXiv.org |

Authors: Adrian Kent (Centre for Quantum Information and Foundations, DAMTP, University of Cambridge and Perimeter Institute for Theoretical Physics)

Experiments have recently been proposed testing whether quantum gravitational interactions generate entanglement between adjacent masses in position superposition states. We propose potentially less challenging experiments that test quantum gravity against theories with classical spacetimes.

2020年10月23日 星期五 下午4:54 | | | gr-qc updates on arXiv.org |

Authors: Mark P. Hertzberg, Mudit Jain

The Standard Model (SM) possesses an instability at high scales that would be catastrophic during or just after inflation, and yet no new physics has been seen to alter this. Furthermore, modern developments in quantum gravity suggest that the SM degrees of freedom are not unique; that a typical low energy effective theory should include a large assortment of hidden sector degrees of freedom. It is therefore puzzling that cosmological constraints from BBN and CMB reveal that the early universe was almost entirely dominated by the SM, when the inflaton $\phi$ could have decayed into many sectors. In this work we propose the following explanation for all of this: we allow the lowest dimension operators with natural coefficients between the inflaton and both the Higgs and hidden sectors. Such hidden sectors are assumed to be entirely natural; this means all unprotected masses are pushed up to high scales and project out of the spectrum, while only massless (or protected) degrees of freedom remain, and so the inflaton can only reheat these sectors through higher dimension (and suppressed) operators. On the other hand, the SM possesses a special feature: it includes a light Higgs $H$, presumably for life to exist, and hence it allows a super-renormalizable coupling to the inflaton $\phi H^\dagger H$, which allows rapid decay into the SM. We show that this naturally (i) removes the instability in the Higgs potential both during and after inflation due to a tree-level effect that increases the value of the Higgs self-coupling from the IR to the UV when one passes the inflaton mass, (ii) explains why the SM is dominant in the early universe, (iii) allows dark matter to form in hidden sector/s through subsequent dynamics (or axions, etc), (iv) allows for high reheating and baryogenesis, and (v) accounts for why there so far has been no direct detection of dark matter or new physics beyond the SM.

2020年10月23日 星期五 下午4:54 | | | gr-qc updates on arXiv.org |

Authors: Bernard S. Kay (York)

We provide a theoretical foundation for the notion of the quantum coherent state of the electrostatic field of a static external charge distribution introduced in a 1998 paper and rederive formulae there for the inner products of a pair of such states. Contrary to what one might expect, these inner products are non-zero whenever the total charges of the two charge distributions are equal, even if the charge distributions themselves differ. We actually display two different frameworks for these same coherent states, in the second of which Gauss’s law only holds in expectation value. We propose an experiment capable of ruling that out. The first framework leads to a ‘product picture’ for full QED — i.e. a reformulation of standard QED in which it has a total Hamiltonian, arising as a sum of a free electromagnetic Hamiltonian, a free charged-matter Hamiltonian and an interaction term, acting on a ‘physical subspace’ of the full tensor product of charged-matter and electromagnetic-field Hilbert spaces. (The traditional Coulomb gauge formulation of QED isn’t a product picture because, in it, the longitudinal part of the electric field is a function of the charged matter operators.) We do this for both Maxwell-Dirac and Maxwell-Schr\”odinger QED. For all states in the physical subspace of each of these systems, the charged matter is entangled with longitudinal photons and Gauss’s law holds on the physical subspace as an operator equation; albeit the electric field operator and the Hamiltonian, while self-adjoint on the physical subspace, fail to be self-adjoint on the full tensor-product Hilbert space. Analogues of our coherent state inner products and of the product picture play a role in the author’s matter-gravity entanglement hypothesis. Also, the product picture amounts to a temporal gauge quantization of QED which appears to be free from the difficulties of previous versions.

2020年10月23日 星期五 下午4:54 | | | gr-qc updates on arXiv.org |

Authors: Luca Marchetti, Daniele Oriti

We discuss the relational strategy to solve the problem of time in quantum gravity and different ways in which it could be implemented, pointing out in particular the fundamentally new dimension that the problem takes in a quantum gravity context in which spacetime and geometry are understood as emergent. We realize concretely the relational strategy we have advocated in the context of the tensorial group field theory formalism for quantum gravity, leading to the extraction of an effective relational cosmological dynamics from quantum geometric models. We analyze in detail the emergent cosmological dynamics, highlighting the improvements over previous work, the contribution of the quantum properties of the relational clock to it, and the interplay between the conditions ensuring a bona fide relational dynamics throughout the cosmological evolution and the existence of a quantum bounce resolving the classical big bang singularity.

2020年10月23日 星期五 下午4:54 | | | gr-qc updates on arXiv.org |

Authors: Tejinder P. Singh

We have recently proposed a Lagrangian in trace dynamics at the Planck scale, for unification of gravitation, Yang-Mills fields, and fermions. Dynamical variables are described by odd-grade (fermionic) and even-grade (bosonic) Grassmann matrices. Evolution takes place in Connes time. At energies much lower than Planck scale, trace dynamics reduces to quantum field theory. In the present paper we explain that the correct understanding of spin requires us to formulate the theory in 8-D octonionic space. The automorphisms of the octonion algebra, which belong to the smallest exceptional Lie group $G_2$, replace space-time diffeomorphisms and internal gauge transformations, bringing them under a common unified fold. Building on earlier work by other researchers on division algebras, we propose the Lorentz-weak unification at the Planck scale, the symmetry group being the stabiliser group of the quaternions inside the octonions. This is one of the two maximal subgroups of $G_2$, the other one being $SU(3)$, the element preserver group of octonions. This latter group, coupled with $U(1)_{em}$, describes the electro-colour symmetry, as shown earlier by Furey. We predict a new massless spin one boson [the Lorentz boson] which should be looked for in experiments. Our Lagrangian correctly describes three fermion generations, through three copies of the group $G_2$, embedded in the exceptional Lie group $F_4$. This is the unification group for the four fundamental interactions, and it also happens to be the automorphism group of the exceptional Jordan algebra. Gravitation is shown to be an emergent classical phenomenon. Whereas at the Planck scale, there is present a quantised version of the Lorentz symmetry, mediated by the Lorentz boson. We argue that at sub-Planck scales, the self-adjoint part of the octonionic trace dynamics bears a relationship with string theory in eleven dimensions.

Mathematical languages shape our understanding of time in physics

2020年10月23日 星期五 上午3:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gisin, Nicolas (2020) Mathematical languages shape our understanding of time in physics. Nature Physics, 16. pp. 114-119.

Real Numbers are the Hidden Variables of Classical Mechanics

2020年10月23日 星期五 上午3:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gisin, Nicolas (2020) Real Numbers are the Hidden Variables of Classical Mechanics. Quantum Studies: Mathematics and Foundations, 7. pp. 197-201.

PROPENSITIES IN A NON-DETERMINISTIC PHYSICS*

2020年10月23日 星期五 上午3:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gisin, Nicolas (1991) PROPENSITIES IN A NON-DETERMINISTIC PHYSICS*. Synthese, 89. pp. 287-297. ISSN 1573-0964

Neural Oscillations as Representations

2020年10月23日 星期五 上午2:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Manolo, Martínez and Marc, Artiga (2020) Neural Oscillations as Representations. [Preprint]

Free will and (in)determinism in the brain: a case for naturalized philosophy

2020年10月19日 星期一 下午2:54 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Vervoort, Louis and Blusiewicz, Tomasz (2020) Free will and (in)determinism in the brain: a case for naturalized philosophy. THEORIA. An International Journal for Theory, History and Foundations of Science, 35 (3). pp. 345-364. ISSN 2171-679X

Isotopy and energy of physical networks

2020年10月19日 星期一 上午8:00 | | | Albert-László Barabási | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 19 October 2020; doi:10.1038/s41567-020-1029-z

Recently, a framework was introduced to model three-dimensional physical networks, such as brain or vascular ones, in a way that does not allow link crossings. Here the authors combine concepts from knot theory and statistical mechanics to be able to distinguish between physical networks with identical wiring but different layouts.

Fundamental mentality in a physical world

2020年10月19日 星期一 上午8:00 | | | Latest Results for Synthese |

**Abstract**

Regardless of whatever else physicalism requires, nearly all philosophers agree that physicalism cannot be true in a world which contains fundamental mentality. I challenge this widely held attitude, and describe a world which is plausibly all-physical, yet which may contain fundamental mentality. This is a world in which priority monism is true—which is the view that the whole of the cosmos is fundamental, with dependence relations directed from the whole to the parts—and which contains only a single mental system, like a brain or computer. Because some properties of the whole are fundamental under priority monism, it follows that that the mental properties of a cosmos-encompassing brain or computer system may be fundamental in a priority monist world. Yet such a world need not contain anything physically unacceptable: the mental properties of the cosmos-encompassing brain or computer can be characterized in a physicalism-friendly functionalist or identity-theoretic way. Thus, as I see it, physicalism need not be false in such a world. This constitutes a challenge to those who hold the view that physicalism is inconsistent with the existence of fundamental mentality.

Do symmetries “explain” conservation principles? The modern converse Noether theorem vs pragmatism

2020年10月18日 星期日 下午2:52 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Brown, Harvey R. (2020) Do symmetries “explain” conservation principles? The modern converse Noether theorem vs pragmatism. [Preprint]

]]>2020年10月16日 星期五 下午8:09 | | | physics.hist-ph updates on arXiv.org |

Authors: William Graham Hoover, Carol Griswold Hoover

This memoir honors the late Berni Julian Alder, who inspired both of us with his pioneering development of molecular dynamics. Berni’s work with Tom Wainwright, described in the 1959 Scientific American[1], brought Bill to interview at Livermore in 1962. Hired by Berni, Bill enjoyed over 40 years’ research at the Laboratory. Berni, along with Edward Teller, founded UC’s Department of Applied Science in 1963. Their motivation was to attract bright students to use the laboratory’s unparalleled research facilities. In 1972 Carol was offered a joint LLNL employee-DAS student appointment at Livermore. Bill, thanks to Berni’s efforts, was already a Professor at DAS. Carol became one of Bill’s best students. Berni’s influence was directly responsible for our physics collaboration and our marriage in 1989. The present work is devoted to two early interests of Berni’s, irreversibility and shockwaves. Berni and Tom studied the irreversibility of Boltzmann’s “H function” in the early 1950s[2]. Berni called shockwaves the “most irreversible” of hydrodynamic processes[3]. Just this past summer, in simulating shockwaves with time-reversible classical mechanics, we found that reversed Runge-Kutta shockwave simulations yielded nonsteady rarefaction waves, not shocks. Intrigued by this unexpected result we studied the exponential Lyapunov instabilities in both wave types. Besides the Runge-Kutta and Leapfrog algorithms, we developed a precisely-reversible manybody algorithm based on trajectory storing, just changing the velocities’ signs to generate the reversed trajectories. Both shocks and rarefactions were precisely reversed. Separate simulations, forward and reversed, provide interesting examples of the Lyapunov-unstable symmetry-breaking models supporting the Second Law of Thermodynamics. We describe promising research directions suggested by this work.

The time distribution of quantum events. (arXiv:2010.07575v1 [quant-ph])

2020年10月16日 星期五 下午8:08 | | | Danijel Jurman, Hrvoje Nikolic | | | quant-ph updates on arXiv.org |

We develop a general theory of the time distribution of quantum events, applicable to a large class of problems such as arrival time, dwell time and tunneling time. The basic assumption is that there is a stopwatch that ticks unless an awaited event is detected, at which time the stopwatch stops. The awaited event is represented by a projection operator $\pi$, while the ideal stopwatch is modeled as a series of ideal projective measurements at different times, so that, at each of those times, the quantum state suffers an instantaneous projection with either $\bar{\pi}=1-\pi$ (when the awaited event does not happen) or $\pi$ (when the awaited event eventually happens). In the approximation in which the time $\delta t$ between the subsequent measurements is sufficiently small, we find a fairly simple general formula for the time distribution ${\cal P}(t)$, representing the probability density that the awaited event will be detected at time $t$.

2020年10月16日 星期五 下午8:08 | | | Sumeet Khatri, Anthony J. Brady, Renée A. Desporte, Manon P. Bart, Jonathan P. Dowling | | | quant-ph updates on arXiv.org |

Recent experimental breakthroughs in satellite quantum communications have opened up the possibility of creating a global quantum internet using satellite links. This approach appears to be particularly viable in the near term, due to the lower attenuation of optical signals from satellite to ground, and due to the currently short coherence times of quantum memories. The latter prevents ground-based entanglement distribution using atmospheric or optical-fiber links at high rates over long distances. In this work, we propose a global-scale quantum internet consisting of a constellation of orbiting satellites that provides a continuous, on-demand entanglement distribution service to ground stations. The satellites can also function as untrusted nodes for the purpose of long-distance quantum-key distribution. We develop a technique for determining optimal satellite configurations with continuous coverage that balances both the total number of satellites and entanglement-distribution rates. Using this technique, we determine various optimal satellite configurations for a polar-orbit constellation, and we analyze the resulting satellite-to-ground loss and achievable entanglement-distribution rates for multiple ground station configurations. We also provide a comparison between these entanglement-distribution rates and the rates of ground-based quantum repeater schemes. Overall, our work provides the theoretical tools and the experimental guidance needed to make a satellite-based global quantum internet a reality.

A New Action for Cosmology. (arXiv:2010.07329v1 [gr-qc])

2020年10月16日 星期五 下午8:08 | | | gr-qc updates on arXiv.org |

Authors: David Sloan

We present a new action which reproduces the cosmological sector of general relativity in both the Friedmann-Lemaitre-Robertson-Walker (FLRW) and Bianchi models. This action makes no reference to the scale factor, and is of a frictional type first examined by Herglotz. We demonstrate that the extremization of this action reproduces the usual dynamics of physical observables, and the symplectification of this action is the Einstein-Hilbert action for cosmological models. We end by discussing some of the increased explanatory power produced by considering the reduced physical ontology resulting from eliminating scale.

Charge Conservation, Entropy Current, and Gravitation. (arXiv:2010.07660v1 [gr-qc])

2020年10月16日 星期五 下午8:08 | | | gr-qc updates on arXiv.org |

Authors: Sinya Aoki, Tetsuya Onogi, Shuichi Yokoyama

We propose a new class of vector fields to construct a conserved charge in a general field theory whose energy momentum tensor is covariantly conserved. We argue that there always exists such a vector field uniquely in a given field theory even without global symmetry and the conserved current constructed from the vector field can be identified with the entropy current of the system. As a piece of evidence we show that the conserved charge defined therefrom satisfies the first law of thermodynamics for an isotropic system with a suitable definition of temperature. We apply our formulation to several gravitational systems such as the expanding universe, Schwarzschild and BTZ black holes, and gravitational plane waves. We confirm the conservation of the proposed entropy density under any homogeneous and isotropic expansion of the universe, the precise reproduction of the Bekenstein-Hawking entropy incorporating the first law of thermodynamics, and the existence of gravitational plane wave carrying no charge, respectively.

2020年10月16日 星期五 下午8:08 | | | gr-qc updates on arXiv.org |

Authors: Patrick Das Gupta

Freeman J. Dyson, a brilliant theoretical physicist and a gifted mathematician, passed away on 28 February 2020 at the age of 96. A vignette of his outstanding contributions to physical sciences, ranging from the subject of quantum electrodynamics to gravitational waves, is provided in this article. Dyson’s futuristic ideas concerning the free will of `intelligent life’ influencing the remote future of the cosmos with `Eternal Intelligence’, Dyson tree, Dyson sphere and so on, have also been discussed briefly.

2020年10月16日 星期五 下午8:08 | | | gr-qc updates on arXiv.org |

Authors: Matsuo Sato, Yuji Sugimoto

String geometry theory is one of the candidates of the non-perturbative formulation of string theory. In arXiv:1709.03506, the perturbative string theory is reproduced from a string geometry model coupled with a $u(1)$ gauge field on string manifolds. In this paper, we generalize this result and we show that the perturbative string theory is reproduced from any string geometry model by taking a Newtonian limit.

2020年10月16日 星期五 下午8:08 | | | gr-qc updates on arXiv.org |

Authors: Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto

We analyze the dynamics of gravity-induced entanglement for N massive particles. Considering a linear configuration of these particles, we investigate the entanglement between a specific pair of particles under the influence of the gravitational interaction between the massive particles. As the particle number increases, the specific particle pair decoheres more easily due to the gravitational interaction with other particles. The time scale of the gravity-induced decoherence is found analytically. We also discuss the entanglement dynamics of initially entangled particles, which exemplify the monogamy of gravity-induced entanglement.

A stronger Bell argument for (some kind of) parameter dependence

2020年10月16日 星期五 下午8:08 | | |

Publication date: Available online 16 October 2020

**Source:** Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics

Author(s): Paul M. Näger

Setting Up Experimental Bell Tests with Reinforcement Learning

2020年10月16日 星期五 下午6:00 | | | Alexey A. Melnikov, Pavel Sekatski, and Nicolas Sangouard | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Alexey A. Melnikov, Pavel Sekatski, and Nicolas Sangouard

Finding optical setups producing measurement results with a targeted probability distribution is hard, as *a priori* the number of possible experimental implementations grows exponentially with the number of modes and the number of devices. To tackle this complexity, we introduce a method combining re…

[Phys. Rev. Lett. 125, 160401] Published Fri Oct 16, 2020

2020年10月15日 星期四 上午2:05 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Earman, John S (2020) Believing the Unbelievable. [Preprint]

There is no new problem for quantum mechanics

2020年10月15日 星期四 上午2:02 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Vaidman, Lev (2020) There is no new problem for quantum mechanics. [Preprint]

The hypothesis of “hidden variables” as a unifying principle in physics.

2020年10月15日 星期四 上午1:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Vervoort, Louis (2020) The hypothesis of “hidden variables” as a unifying principle in physics. [Preprint]

2020年10月13日 星期二 上午7:32 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Norton, John (2020) Author’s Responses. [Preprint]

2020年10月12日 星期一 下午3:41 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Barandes, Jacob A. (2019) Can Magnetic Forces Do Work? [Preprint]

Manifestly Covariant Lagrangians, Classical Particles with Spin, and the Origins of Gauge Invariance

2020年10月12日 星期一 下午3:40 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Barandes, Jacob A. (2019) Manifestly Covariant Lagrangians, Classical Particles with Spin, and the Origins of Gauge Invariance. [Preprint]

C-theories of time: On the adirectionality of time

2020年10月12日 星期一 下午3:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Farr, Matt (2020) C-theories of time: On the adirectionality of time. [Preprint]

2020年10月11日 星期日 上午6:16 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Earman, John S (2020) Symmetries for Quantum Theory. [Preprint]

A Synopsis of the Minimal Modal Interpretation of Quantum Theory

2020年10月11日 星期日 上午5:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Barandes, Jacob A. and Kagan, David (2014) A Synopsis of the Minimal Modal Interpretation of Quantum Theory. [Preprint]

The Minimal Modal Interpretation of Quantum Theory

2020年10月11日 星期日 上午5:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Barandes, Jacob A. and Kagan, David (2014) The Minimal Modal Interpretation of Quantum Theory. [Preprint]

Uncomputable but complete physics theory of the universe

2020年10月11日 星期日 上午5:36 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Icefield, William (2020) Uncomputable but complete physics theory of the universe. [Preprint]

Can the universe be in a mixed state?

2020年10月11日 星期日 上午5:35 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2020) Can the universe be in a mixed state? [Preprint]

]]>More at https://sciencex.com/news/2020-10-einstein-opportunity-spooky-actions-distance.html

]]>As it follows from this paradox, the quantum mechanical superposition principle is incompatible with the laws of classical mechanics on scales exceeding atomic scales. Consequently, there must be some mechanism that limits the validity of the superposition principle in quantum systems, where similar paradoxes arise, but which is not taken into account in the standard formalism of quantum mechanics. Here the question arises: “Does this mechanism already exist at the microlevel or does it arise ‘somewhere along the way from the microlevel to the macrolevel’?” It is now generally accepted that at the microlevel the validity of the superposition principle for closed one-particle systems is beyond doubt, and this mechanism (the decoherence mechanism) appears “somewhere along the way”.

However, there is reason to believe that for closed microsystems with a finite number of degrees of freedom, restrictions on the superposition principle already exist at the microlevel, and these restrictions are dictated by superselection rules. These rules should arise in quantum models of closed systems, in which spontaneous symmetry breaking occurs. A recent paper arXiv: 1805.03952v9 shows that this rule arises in the scattering state space, which describes the scattering of a particle by a one-dimensional delta potential barrier (no bound states).

In our opinion, the thought experiment with a cat, proposed by Schrödinger, played a dual role in discussions on the foundations of quantum mechanics. On the one hand, it (correctly) shows that it is the superposition principle that can cause the conflict between quantum mechanics and classical mechanics. On the other hand, due to the fact that a macroscopic object (cat) was included in the experiment, it involuntarily leads to the (erroneous) thought that the problem with the principle of superposition arises precisely at the macro level.

However, the superposition principle (in its current formulation) leads to paradoxes in some quantum problems precisely at the micro level. In other words, quantum mechanics with the superposition principle (in its current formulation) is itself internally inconsistent. And this can be shown by the example of the above mentioned one-dimensional scattering problem. The fact is that the modern quantum-mechanical description of this scattering process is based on two key provisions: (1) the states of a particle are scattering states, each of which has one in-asymptote and one out-asymptote — in the infinitely distant past and distant future, a particle moves as a free particle; (2) the Hamiltonian with the delta potential is self-adjoint — asymptotically free scattering states describe a unitary quantum dynamics.

But the specificity of this one-dimensional problem is that the out-asymptote, in the case of a one-sided incidence of a particle on the barrier, is a superposition of the left and right out-asymptotes. This means that this scattering process splits into two alternative subprocesses – transmission through the barrier (tunneling) and reflection from it. In other words, the provision about the existence of free dynamics, in this scattering process, in the infinitely distant future implies the division of this process into subprocesses. But this means that the quantum dynamics of a particle in this process is not unitary, which contradicts the second provision about the self-adjointness of the Hamiltonian in this problem. That is, the modern quantum model of the process of scattering a particle on a one-dimensional delta potential is contradictory – it (even without cat) contains a paradox! Its solution is suggested in the paper arXiv: 1805.03952v9.

]]>上午9:34 | | | Roope Uola, Tristan Kraft, Sébastien Designolle, Nikolai Miklin, Armin Tavakoli, Juha-Pekka Pellonpää, Otfried Gühne, Nicolas Brunner | | | quant-ph updates on arXiv.org |

We consider the question of characterising the incompatibility of sets of high-dimensional quantum measurements. We introduce the concept of measurement incompatibility in subspaces. That is, starting from a set of measurements that is incompatible, one considers the set of measurements obtained by projection onto any strict subspace of fixed dimension. We identify three possible forms of incompatibility in subspaces: (i) incompressible incompatibility: measurements that become compatible in every subspace, (ii) fully compressible incompatibility: measurements that remain incompatible in every subspace, and (iii) partly compressible incompatibility: measurements that are compatible in some subspace and incompatible in another. For each class we discuss explicit examples. Finally, we present some applications of these ideas. First we show that joint measurability and coexistence are two inequivalent notions of incompatibility in the simplest case of qubit systems. Second we highlight the implications of our results for tests of quantum steering.

Quantum Zeno effect for open quantum systems. (arXiv:2010.04121v1 [quant-ph])

上午9:34 | | | Simon Becker, Nilanjana Datta, Robert Salzmann | | | quant-ph updates on arXiv.org |

We prove the quantum Zeno effect in open quantum systems whose evolution, governed by quantum dynamical semigroups, is repeatedly and frequently interrupted by the action of a quantum operation. For the case of a quantum dynamical semigroup with a bounded generator, our analysis leads to a refinement of existing results and extends them to a larger class of quantum operations. We also prove the existence of a novel strong quantum Zeno limit for quantum operations for which a certain spectral gap assumption, which all previous results relied on, is lifted. The quantum operations are instead required to satisfy a weaker property of strong power-convergence. In addition, we establish, for the first time, the existence of a quantum Zeno limit for the case of unbounded generators. We also provide a variety of physically interesting examples of quantum operations to which our results apply.

上午9:34 | | | Diego González, Diego Fernández de la Pradilla, Guillermo González | | | quant-ph updates on arXiv.org |

Bell-type inequalities allow for experimental testing of local hidden variable theories. In the present work we show the violation of Mermin’s inequalities in IBM’s five-qubit quantum computers, ruling out the local realism hypothesis in quantum mechanics. Furthermore, our numerical results show significant improvement with respect to previous implementations. The circuit implementation of these inequalities is also proposed as a way of assessing the reliability of different quantum computers.

上午9:34 | | | physics.hist-ph updates on arXiv.org |

Authors: Michael J.W. Hall

A 1964 paper by John Bell gave the first demonstration that quantum mechanics is incompatible with local hidden variables. There is an ongoing and vigorous debate on whether he relied on an assumption of determinism, or instead, as he later claimed, derived determinism from assumptions of locality and perfect correlation. This paper aims to bring clarity to the debate via simple examples and rigorous results. It is shown that the weak form of locality used in Bell’s 1964 paper (parameter independence) is insufficient for such a derivation, whereas an independent form called outcome independence is sufficient even when weak locality does not hold. It further follows that outcome independence, by itself, implies that standard quantum mechanics is incomplete. It is also shown that an appeal by Bell to the Einstein-Rosen-Podolsky argument to support his claim fails, via examples that expose logical gaps in this argument. However, replacing the reality criterion underpinning the argument by a stronger criterion enables a rigorous derivation of both weak locality and determinism, as required for Bell’s 1964 paper. Consequences for quantum interpretations, locality, and classical common causes are briefly discussed, with reference to an example of local classical indeterminism.

Exponential corrected thermodynamics of black holes. (arXiv:2010.03946v1 [gr-qc])

上午9:34 | | | gr-qc updates on arXiv.org |

Authors: Behnam Pourhassan

Recently, it is reported that thermal fluctuations which are interpreted as quantum effects, modify black holes entropy by an exponential term. We now find the effect of such modification on black hole mass and other thermodynamics quantities. We find that Schwarzschild black hole mass decreased by thermal fluctuations. Hence, we study exponential corrected thermodynamics and statistics of black holes by computing the partition function. We obtain special condition on the event horizon radius to satisfy Smarr-Gibbs-Duhem relation in the presence of quantum correction. As we know the Schwarzschild black hole is unstable, while the effect of exponential correction is the stability of $4D$ Schwarzschild black hole as well as the Schwarzschild-AdS black hole at a small area. On the other hand, a $5D$ Schwarzschild black hole is completely unstable. The effect of quantum correction on the Reissner-Nordstr\”{o}m black hole is instability at quantum scales. Finally, we consider the most general case of charged AdS black hole and study corrected thermodynamics.

How to form a wormhole. (arXiv:2010.03947v1 [gr-qc])

上午9:34 | | | gr-qc updates on arXiv.org |

Authors: De-Chang Dai, Djordje Minic, Dejan Stojkovic

We provide a simple but very useful description of the process of wormhole formation. We place two massive objects in two parallel universes (modeled by two branes). Gravitational attraction between the objects competes with the resistance coming from the brane tension. For sufficiently strong attraction, the branes are deformed, objects touch and a wormhole is formed. Our calculations show that more massive and compact objects are more likely to fulfill the conditions for wormhole formation. This implies that we should be looking for wormholes either in the background of black holes and compact stars, or massive microscopic relics. Our formation mechanism applies equally well for a wormhole connecting two objects in the same universe.

上午9:34 | | | gr-qc updates on arXiv.org |

Authors: Vladimir V. Kassandrov, Nina V. Markova

We consider the model of the self-gravity driven spontaneous wavefunction reduction proposed by L. Diosi, R. Penrose et al. and based on a self-consistent system of the Schrodinger and Poisson equations. An analogous system of coupled Dirac and Maxwell-like equations is proposed as a relativization. Regular solutions to the latter form a discrete spectrum in which all the “active” gravitational masses are always positive, and approximately equal to inertial masses and to the mass $m$ of the quanta of Dirac field up to the corrections of order $\alpha^2$. Here $\alpha=(m/M_{pl})^2$ is the gravitational analogue of the fine structure constant negligibly small for nucleons. In the limit $\alpha \to 0$ the model reduces back to the nonrelativistic Schrodinger-Newton one. The equivalence principle is fulfilled with an extremely high precision. The above solutions correspond to various states of the same (free) particle rather than to different particles. These states possess a negligibly small difference in characteristics but essentially differ in the widths of the wavefunctions. For the ground state the latter is $\alpha$ times larger the Compton length, so that a nucleon cannot be sufficiently localized to model the reduction process

A Unified Combination of Classical and Quantum Systems. (arXiv:2010.03984v1 [quant-ph])

上午9:34 | | | gr-qc updates on arXiv.org |

Authors: John R. Klauder

Any particular classical system and its quantum version are normally viewed as separate formulations that are strictly distinct. Our goal is to overcome the two separate languages and create a smooth and common procedure that provides a clear and continuous passage between the conventional distinction of either a strictly classical or a strictly quantized state. While path integration, among other procedures, provides an alternative route to connect classical and quantum expressions, it normally involves complicated, model-dependent, integrations. Our alternative procedures involve only model-independent procedures, and use more natural and straightforward integrations that are universal in kind. To introduce the basic procedures our presentation begins with familiar methods that are limited to basic, conventional, canonical quantum mechanical examples. In the final sections we illustrate how alternative quantization procedures, e.g., spin and affine quantizations, can also have smooth paths between classical and quantum stories, and with a few brief remarks, can also lead to similar stories for non-renormalizable covariant scalar fields as well as quantum gravity.

上午9:34 | | | gr-qc updates on arXiv.org |

Authors: Jerome Martin, Vincent Vennin

Our recent letter “Cosmic Microwave Background Constraints Cast a Shadow On Continuous Spontaneous Localization Models” has recently been criticised in [G. R. Bengochea, G. Leon, P. Pearle, and D. Sudarsky, arXiv:2006.05313 and arXiv:2008.05285]. In this reply, we explain why the arguments presented in those articles are either incorrect or a confirmation of the robustness of our results.

Flow: the Axiom of Choice is independent from the Partition Principle

上午5:41 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Sant’Anna, Adonai and Bueno, Otávio and de França, Márcio and Brodzinski, Renato (2020) Flow: the Axiom of Choice is independent from the Partition Principle. [Preprint]

上午5:41 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Kurpaska, Sławomir and Tyszka, Apoloniusz (2020) The physical limits of computation inspire an open problem that concerns abstract computable sets X⊆N and cannot be formalized in the set theory ZFC as it refers to our current knowledge on X. [Preprint]

Coming to America: Carnap, Reichenbach and the Great Intellectual Migration. Part I: Rudolf Carnap

2020年10月9日 星期五 上午12:27 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Verhaegh, Sander (2020) Coming to America: Carnap, Reichenbach and the Great Intellectual Migration. Part I: Rudolf Carnap. [Preprint]

2020年10月7日 星期三 下午2:32 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

John, S (2020) Implementing David Lewis’ Principal Principle: A Program for Investigating the Relation between Credence and Chance. [Preprint]

Intercontinental comparison of optical atomic clocks through very long baseline interferometry

2020年10月5日 星期一 上午8:00 | | | Tetsuya Ido | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 05 October 2020; doi:10.1038/s41567-020-01038-6

Very long baseline interferometry is used to compare two optical clocks located in Japan and Italy through the observation of extragalactic radio sources. This approach overcomes limitations of the performance of satellite transfer techniques.

2020年10月5日 星期一 上午8:00 | | | Barbara Webb | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 05 October 2020; doi:10.1038/s41567-020-01058-2

Animals seem capable of an infinite variety of movement, yet also exhibit substantial stereotypy in repeated actions. A beautiful view of worm behaviour now shows that the worm’s state evolves deterministically but is bounced chaotically between unstable periodic orbits.

]]>2020年9月30日 星期三 上午1:12 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

ROVELLI, Carlo (2020) Gauge Is More Than Mathematical Redundancy. [Preprint]

Measurement and Quantum Dynamics in the Minimal Modal Interpretation of Quantum Theory

上午4:41 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Barandes, Jacob A. and Kagan, David (2020) Measurement and Quantum Dynamics in the Minimal Modal Interpretation of Quantum Theory. Foundations of Physics, 50 (10). pp. 1189-1218.

A New Perspective On Time And Physical Laws

上午12:59 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

James, Lucy (2020) A New Perspective On Time And Physical Laws. [Preprint]

Quantum probability’s algebraic origin

上午12:48 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Niestegge, Gerd (2020) Quantum probability’s algebraic origin. [Preprint]

Learning Entropy Production via Neural Networks

2020年10月2日 星期五 下午6:00 | | | Dong-Kyum Kim, Youngkyoung Bae, Sangyun Lee, and Hawoong Jeong | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Dong-Kyum Kim, Youngkyoung Bae, Sangyun Lee, and Hawoong Jeong

This Letter presents a neural estimator for entropy production (NEEP), that estimates entropy production (EP) from trajectories of relevant variables without detailed information on the system dynamics. For steady state, we rigorously prove that the estimator, which can be built up from different ch…

[Phys. Rev. Lett. 125, 140604] Published Fri Oct 02, 2020

The Vienna Delayed-Choice Quantum Eraser Leaves No Choice. (arXiv:2010.00049v1 [quant-ph])

2020年10月2日 星期五 上午10:04 | | | Tabish Qureshi | | | quant-ph updates on arXiv.org |

A realizable delayed-choice quantum eraser, using a modified Mach-Zehnder (MZ) interferometer and polarization entangled photons, is theoretically analyzed here. The signal photon goes through a modified MZ interferometer, and the polarization of the idler photon provides path information for the signal photon. The setup is very similar to the delayed-choice quantum eraser experimentally studied by the Vienna group. It is demonstrated that in the class of quantum erasers with discrete output states, the delayed mode leaves no choice for the experimenter. The which-way information is always erased, and every detected signal photon fixes the polarization state of the idler, and thus gives information on precisely how the signal photon traversed the two paths. The analysis shows that the Vienna delayed-choice quantum eraser is the first experimental demonstration of the fact that the delayed mode leaves no choice for the experimenter, and the which-way information is always erased.

2020年10月2日 星期五 上午10:04 | | | Banibrata Mukhopadhyay, Soumya Kanti Ganguly | | | quant-ph updates on arXiv.org |

We show Zeeman-like splitting in the energy of spinors propagating in a background gravitational field, analogous to the spinors in an electromagnetic field, otherwise termed the Gravitational Zeeman Effect. These spinors are also found to acquire a geometric phase, in a similar way as they do in the presence of magnetic fields. However, in a gravitational background, the Aharonov-Bohm type effect, in addition to Berry-like phase, arises. Based on this result, we investigate geometric phases acquired by neutrinos propagating in a strong gravitational field. We also explore entanglement of neutrino states due to gravity, which could induce neutrino-antineutrino oscillation in the first place. We show that entangled states also acquire geometric phases which are determined by the relative strength between gravitational field and neutrino masses.

2020年10月2日 星期五 上午10:04 | | | Stephen Bruce Sontz | | | quant-ph updates on arXiv.org |

In this treatise I introduce the time dependent Generalized Born’s Rule for the probabilities of quantum events, including conditional and consecutive probabilities, as the unique fundamental time evolution equation of quantum theory. Then these probabilities, computed from states and events, are to be compared with relative frequencies of observations. Schrodinger’s equation still is valid in one model of the axioms of quantum theory, which I call the Schrodinger model. However, the role of Schrodinger’s equation is auxiliary, since it serves to help compute the continuous temporal evolution of the probabilities given by the Generalized Born’s Rule. In other models, such as the Heisenberg model, the auxiliary equations are quite different, but the Generalized Born’s Rule is the same formula (covariance) and gives the same results (invariance). Also some aspects of the Schrodinger model are not found in the isomorphic Heisenberg model, and they therefore do not have any physical significance. One example of this is the infamous collapse of the quantum state. Other quantum phenomena, such as entanglement, are easy to analyze in terms of the Generalized Born’s Rule without any reference to the unnecessary concept of collapse. Finally, this leads to the possibility of quantum theory with other sorts of auxiliary equations instead of Schrodinger’s equation, and examples of this are given. Throughout this treatise the leit motif is the central importance of quantum probability and most especially of the simplifying role of the time dependent Generalized Born’s Rule in quantum theory.

Unveiling A Hidden Classical-Quantum Link. (arXiv:2009.08308v2 [quant-ph] UPDATED)

2020年10月2日 星期五 上午10:04 | | | Partha Ghose | | | quant-ph updates on arXiv.org |

The conceptual divide between classical physics and quantum mechanics has not been satisfactorily bridged as yet. The purpose of this paper is to show that such a bridge exists naturally in the Green-Wolf complex scalar representation of electromagnetic fields and its extension to massive fields. The quantum mechanical theory of radiation that follows from the the Green-Wolf representation is applied to the cosmic microwave background radiation (CMBR) regarded as a universal medium, and the implications are explored.

Temperaturskalan och Boltzmanns konstant. (arXiv:2010.00470v1 [physics.hist-ph])

2020年10月2日 星期五 上午10:04 | | | physics.hist-ph updates on arXiv.org |

Authors: G.J. Ehnholm, M. Krusius

Temperature scale and the Boltzmann constant: The newest system of units is based on a compatible set of natural constants with fixed values. An example is the Boltzmann constant k which defines the thermal energy content kT. To express the base unit T, the absolute temperature in kelvin, an international agreement for the temperature scale is needed. The scale is defined using fixed points, which are temperatures of various phase transitions. Especially important has been the triple point of water at 273.1600 K. These fixed point temperatures determine the international temperature scale ITS within the Si system. Temperature measurement itself is based on physical laws and on the properties of appropriate thermometric materials selected to determine the temperature scale. For determining the Boltzmann constant, new precision techniques have been developed during the last two decades. Examples are different types of gas thermometry, which ultimately are based on the ideal gas law, and thermal noise of electric charge carriers in conductors. With these means it has become possible to fix the value of the Boltzmann constant with a relative uncertainty of < 1 ppm. As of 2019, the value of k has been agreed to be fixed at 1.380649×10^(-23) J/K. This agreement replaces the earlier definition of a Kelvin degree.

2020年10月2日 星期五 上午10:04 | | | physics.hist-ph updates on arXiv.org |

Authors: A. A. Sheykin, S. N. Manida

We study the properties of fundamental physical constants using the threefold classification of dimensional constants proposed by J.-M. L{\’e}vy-Leblond: constants of objects (masses, etc.), constants of phenomena (coupling constants), and “universal constants” (such as $c$ and $\hbar$). We show that all of the known “natural” systems of units contain at least one non-universal constant. We discuss the possible consequences of such non-universality, e.g., the dependence of some of these systems on the number of spatial dimensions. In the search for a “fully universal” system of units, we propose a set of constants that consists of $c$, $\hbar$, and a length parameter and discuss its origins and the connection to the possible kinematic groups discovered by L{\’e}vy-Leblond and Bacry. Finally, we give some comments about the interpretation of these constants.

The dynamical approach to spin-2 gravity

2020年10月2日 星期五 上午10:04 | | |

Publication date: Available online 28 September 2020

**Source:** Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics

Author(s): Kian Salimkhani

Proca in the sky. (arXiv:2010.00513v1 [astro-ph.CO])

2020年10月2日 星期五 上午10:04 | | | gr-qc updates on arXiv.org |

Authors: Lavinia Heisenberg, Hector Villarrubia-Rojo

The standard model of cosmology, the $\Lambda$CDM model, describes the evolution of the Universe since the Big Bang with just a few parameters, six in its basic form. Despite being the simplest model, direct late-time measurements of the Hubble constant compared with the early-universe measurements result in the so-called $H_0$ tension. It is claimed that a late time resolution is predestined to fail when different cosmological probes are combined. In this work, we shake the ground of this belief with a very simple model. We show how, in the context of cubic vector Galileon models, the Hubble tension can naturally be relieved using a combination of CMB, BAO and SNe observations without using any prior on $H_0$ . The tension can be reduced even further by including the local measurement of the Hubble constant.

Can a nonextremal black hole be a particle accelerator?. (arXiv:2007.09413v2 [gr-qc] UPDATED)

2020年10月2日 星期五 上午10:04 | | | gr-qc updates on arXiv.org |

Authors: O. B. Zaslavskii

We consider particle collisions in the background of a nonextremal black hole. Two particles fall from infinity, particle 1 is fine-tuned (critical), collision occurs in its turning point. The first example is the Reissner-Nordstr\”{o}m (RN) one. If the energy at infinity $E_{1}$ is big enough, the turning point is close to the horizon. Then, we derive a simple formula according to which $E_{c.m.}\sim E_{1}\kappa ^{-1/2}$, where $\kappa $ is a surface gravity. Thus significant growth of $E_{c.m.}$ is possible if (i) particle 1 is ultrarelativistic (if both particles are ultrarelativistic, this gives gain as compared to collisions in flat space-time), (ii) a black hole is near-extremal (small $\kappa $). In the scenario of multiple collisions the energy $E_{c.m.}$ is finite in each individual collision. However, it can grow in subsequent collisions, provided new near-critical particles are heavy enough. For neutral rotating black holes, in case (i) a turning point remains far from the horizon but large $E_{c.m.}$ is still possible. Case (ii) is similar to that for collisions in the RN metric. We develop a general theoretical scheme, direct astrophysical applications can be a next step to be studied.

A Principle Explanation of Bell State Entanglement: Conservation per No Preferred Reference Frame

2020年10月1日 星期四 下午4:09 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Stuckey, W. M. and Silberstein, Michael (2020) A Principle Explanation of Bell State Entanglement: Conservation per No Preferred Reference Frame. In: UNSPECIFIED.

2020年10月1日 星期四 上午8:00 | | | Elizaveta Dubrovina | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 01 October 2020; doi:10.1038/s41567-020-01051-9

Over the last 15 years, the content of Nature Physics has covered an enormous breadth of subjects at the forefront of physics. The journal’s past and present editors recount their favourite papers and what made chaperoning them to publication special.

2020年10月1日 星期四 上午8:00 | | | Stefanie Reichert | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 01 October 2020; doi:10.1038/s41567-020-01067-1

Mind the gap

2020年10月1日 星期四 上午8:00 | | | Richard Brierley | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 01 October 2020; doi:10.1038/s41567-020-01065-3

Ising model for strings

INFORMATION-DEVOID ROUTES FOR SCALE-FREE NEURODYNAMICS

2020年10月1日 星期四 上午6:04 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Tozzi, Arturo and Peters, James (2020) INFORMATION-DEVOID ROUTES FOR SCALE-FREE NEURODYNAMICS. [Preprint]

What does the world look like according to superdeterminism?

2020年9月30日 星期三 上午1:37 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Le Bihan, Baptiste (2020) What does the world look like according to superdeterminism? [Preprint]

Inference to the Best Explanation and Norton’s Material Theory of Induction.

2020年9月30日 星期三 上午1:33 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Davey, Kevin (2020) Inference to the Best Explanation and Norton’s Material Theory of Induction. [Preprint]

Answering Mermin’s challenge with conservation per no preferred reference frame

2020年9月30日 星期三 上午1:31 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Stuckey, W. M. and Silberstein, Michael and McDevitt, Timothy and Le, T.D. (2020) Answering Mermin’s challenge with conservation per no preferred reference frame. Scientific Reports, 10 (15771).

The Role of Meta-Empirical Theory Assessment in the Acceptance of Atomism

2020年9月30日 星期三 上午1:18 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Dawid, Richard (2020) The Role of Meta-Empirical Theory Assessment in the Acceptance of Atomism. [Preprint]

Gauge Invariance for Classical Massless Particles with Spin

2020年9月30日 星期三 上午1:14 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Barandes, Jacob A. (2019) Gauge Invariance for Classical Massless Particles with Spin. [Preprint]

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