上午10:17 | | | Oisin Culhane, Mark T. Mitchison, John Goold | | | quant-ph updates on arXiv.org |

Recent experiments have demonstrated the generation of coherent mechanical oscillations in a suspended carbon nanotube, which are driven by an electric current through the device above a certain voltage threshold, in close analogy with a lasing transition. We investigate this phenomenon from the perspective of work extraction, by modelling a nano-electromechanical device as a quantum flywheel or battery that converts electrical power into stored mechanical energy. We introduce a microscopic model that qualitatively matches the experimental finding, and compute the Wigner function of the quantum vibrational mode in its non-equilibrium steady-state. We characterise the threshold for self-sustained oscillations using two approaches to quantifying work deposition in non-equilibrium quantum thermodynamics: the ergotropy and the non-equilibrium free energy. We find that ergotropy serves as an order parameter for the phonon lasing transition. The framework we employ to describe work extraction is general and widely transferable to other mesoscopic quantum devices.

上午10:17 | | | Petr Jizba, Gaetano Lambiase, Giuseppe Gaetano Luciano, Luciano Petruzziello | | | quant-ph updates on arXiv.org |

The generalized uncertainty principle (GUP) is a phenomenological model whose purpose is to account for a minimal length scale (e.g., Planck scale or characteristic inverse-mass scale in effective quantum description) in quantum systems. In this Letter, we study possible observational effects of GUP systems in their decoherence domain. We first derive coherent states associated to GUP and unveil that in the momentum representation they coincide with Tsallis’ probability amplitudes, whose non-extensivity parameter $q$ monotonically increases with the GUP deformation parameter $\beta$. Secondly, for $\beta < 0$ (i.e., $q < 1$), we show that, due to Bekner-Babenko inequality, the GUP is fully equivalent to information-theoretic uncertainty relations based on Tsallis-entropy-power. Finally, we invoke the Maximal Entropy principle known from estimation theory to reveal connection between the quasi-classical (decoherence) limit of GUP-related quantum theory and non-extensive thermostatistics of Tsallis. This might provide an exciting paradigm in a range of fields from quantum theory to analog gravity. For instance, in some quantum gravity theories, such as conformal gravity, aforementioned quasi-classical regime has relevant observational consequences. We discuss some of the implications.

Generation of vortex particles via weak measurements. (arXiv:2201.07997v1 [hep-ph])

上午10:17 | | | D. V. Karlovets, G. Geloni, G. K. Sizykh, V. G. Serbo | | | quant-ph updates on arXiv.org |

While twisted photons with orbital angular momentum can be generated in several ways, their massive counterparts — vortex electrons, neutrons, or atoms — can be obtained so far only via diffraction techniques, not applicable for relativistic energies. Here we show that particles with phase vortices, including hadrons, ions, and nuclei, can be generated during emission in helical undulators, via Cherenkov radiation, in collisions with intense laser beams, in such scattering and annihilation processes as $e\mu \to e\mu, ep \to ep$, etc. We elucidate that the key element in obtaining them is not the process itself but the post-selection protocol due to quantum entanglement. A final particle acquires a phase vortex if the other final particle’s momentum is weakly measured with no post-selection of its azimuthal angle. This technique can be used for generating all types of vortex particles, it can be adapted for ultrarelativistic beams of modern colliders for hadronic and spin studies, and it can also facilitate the development of sources of hard X-ray and $\gamma$-range twisted photons.

上午10:17 | | | M. Bauer, C.A. Aguillón | | | quant-ph updates on arXiv.org |

Canonical quantization applied to closed systems leads to static equations, the Wheeler-deWitt equation in Quantum Gravity and the time independent Schr\”odinger equation in Quantum Mechanics. How to restore time is the Problem of Time(s). Integrating developments are: a) entanglement of a microscopic system with its classical environment accords it a time evolution description, the time dependent Schr\”odinger equation, where t is the laboratory time measured by clocks; b) canonical quantization of Special Relativity yields both the Dirac Hamiltonian and a self adjoint “time” operator, restoring to position and time the equivalent footing accorded to energy and momentum in Relativistic Quantum Mechanics. It introduces an intrinsic time property {\tau} associated with the mass of the system, and a basis additional to the usual configuration, momentum and energy basis. As a generator of momentum displacements and consequently of energy, it invalidates Pauli’s objection to the existence of a time operator. It furthermore complies with the requirements to condition the other observables in the conditional interpretation of QG. As Pauli’s objection figures explicit or implicitly in most current developments of QM and QG, its invalidation opens to research the effect of this new two times perspective on such developments.

Anomalous weak values are caused by disturbance. (arXiv:2108.04733v3 [quant-ph] UPDATED)

上午10:17 | | | Asger C. Ipsen | | | quant-ph updates on arXiv.org |

In combination with post-selection, weak measurements can lead to surprising results known as anomalous weak values. These lie outside the bounds of the spectrum of the relevant observable, as in the canonical example of measuring the spin of an electron (along some axis) to be 100. We argue that the disturbance caused by the weak measurement, while small, is sufficient to significantly affect the measurement result, and that this is the most reasonable explanation of anomalous weak values.

On Circular Orbits in Einstein’s Theory of Gravitation. (arXiv:2201.07971v1 [physics.hist-ph])

上午10:16 | | | physics.hist-ph updates on arXiv.org |

Authors: S.A. Kaplan

The preprint is an English translation of the paper by famous astrophysicist Samuil Kaplan (1921-1978) “O krugovykh orbitakh v teorii tyagoteniya Einsteina (On circular orbits in Einstein’s theory of gravitation)”, published in 1949 in the Journal of Experimental and Theoretical Physics (Vol. 19, No. 10, pp. 951-952) in Russian. This important 1 and 1/3 page paper is still inaccessible to a wide range of experts and students due to the lack of such translation. This paper is the first scientific publication of Samuil Kaplan and the pioneering work in this field. The aim of this presentation is to make the article available to a wide range of experts in the field of general relativity, relativistic astrophysics and the history of science, as well as to honor its author on the occasion of the 100th anniversary of his birth.

Lost Horizon? — Modeling Black Holes in String Theory. (arXiv:2201.08250v1 [physics.hist-ph])

上午10:16 | | | physics.hist-ph updates on arXiv.org |

Authors: Nick Huggett, Keizo Matsubara

The modeling of black holes is an important desideratum for any quantum theory of gravity. Not only is a classical black hole metric sought, but also agreement with the laws of black hole thermodynamics. In this paper, we describe how these goals are obtained in string theory. We review black hole thermodynamics, and then explicate the general stringy derivation of classical spacetimes, the construction of a simple black hole solution, and the derivation of its entropy. With that in hand, we address some important philosophical and conceptual questions: the confirmatory value of the derivation, the bearing of the model on recent discussions of the so-called ‘information paradox’, and the implications of the model for the nature of space.

上午10:16 | | | gr-qc updates on arXiv.org |

Authors: Ruben Campos Delgado

Starting from an effective action for quantum gravity, we calculate the quantum gravitational corrections to the Wald entropy of a four dimensional non-extremal Reissner-Nordstr\”om (RN) black hole in the limit of small electric charge, generalising a previous calculation carried out by Calmet and Kuipers [1] for a Schwarzschild black hole. We show that, at second order in the Ricci curvature, the RN metric receives quantum corrections which shift the classical position of the event horizon. We apply the Wald entropy formula by integrating over the perimeter of the quantum corrected event horizon. We then compute the quantum gravitational corrections to the temperature and the pressure of the black hole.

On the origin of cosmic web. (arXiv:2201.06882v2 [astro-ph.CO] UPDATED)

上午10:16 | | | gr-qc updates on arXiv.org |

Authors: V.G.Gurzadyan, N.N.Fimin, V.M.Chechetkin

The emergence of one and two-dimensional configurations — Zeldovich pancakes — progenitors of the observed filaments and clusters and groups of galaxies, is predicted by means of a developed kinetic approach in analyzing the evolution of initial density perturbations. The self-consistent gravitational interaction described by Vlasov-Poisson set of equations with branching conditions is shown to predict two-dimensional structures as of layers of increased density and voids between them, i.e. the cellular macro-structure of the Universe. The modified potential of weak-field General Relativity is involved, which enables one to explain the Hubble tension, revealing the conceptual discrepancy in the local galactic flows and the cosmological expansion. This demonstrates the possible essential role of self-consistent gravity in the formation of the cosmic web.

The End of Expansion. (arXiv:2201.07704v1 [astro-ph.CO] CROSS LISTED)

上午10:16 | | | gr-qc updates on arXiv.org |

Authors: Cosmin Andrei, Anna Ijjas, Paul J. Steinhardt

If dark energy is a form of quintessence driven by a scalar field $\phi$ evolving down a monotonically decreasing potential $V(\phi)$ that passes sufficiently below zero, the universe is destined to undergo a series of smooth transitions: the currently observed accelerated expansion will cease; soon thereafter, expansion will come to end altogether; and the universe will pass into a phase of slow contraction. In this paper, we consider how short the remaining period of expansion can be given current observational constraints on dark energy. We also discuss how this scenario fits naturally with cyclic cosmologies and recent conjectures about quantum gravity.

On the objectivity of measurement outcomes

2022年1月20日 星期四 下午7:24 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Okon, Elias (2022) On the objectivity of measurement outcomes. [Preprint]

2022年1月20日 星期四 下午6:00 | | | Xiaosong Zhu, Peixiang Lu, and Manfred Lein | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Xiaosong Zhu, Peixiang Lu, and Manfred Lein

If the time evolution of a quantum state leads back to the initial state, a geometric phase is accumulated that is known as the Berry phase for adiabatic evolution or as the Aharonov-Anandan (AA) phase for nonadiabatic evolution. We evaluate these geometric phases using Floquet theory for systems in…

[Phys. Rev. Lett. 128, 030401] Published Thu Jan 20, 2022

Realizing discontinuous quantum phase transitions in a strongly correlated driven optical lattice

2022年1月20日 星期四 上午8:00 | | | Ulrich Schneider | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 20 January 2022; doi:10.1038/s41567-021-01476-w

Studies of first-order phase transitions in quantum simulators have so far been restricted to the weakly interacting regime. A tunable discontinuous phase transition has now been realized with strongly correlated atoms in a driven optical lattice.

Branch-counting in the Everett interpretation of quantum mechanics

2022年1月18日 星期二 下午6:22 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Saunders, Simon (2021) Branch-counting in the Everett interpretation of quantum mechanics. Proceedings of the Royal Society A, 477.

All quantum mixtures are proper

2022年1月16日 星期日 上午3:15 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Castellani, Leonardo (2022) All quantum mixtures are proper. [Preprint]

]]>上午10:15 | | | Peter Morgan | | | quant-ph updates on arXiv.org |

Classical and quantum measurement theories are usually held to be different because the algebra of classical measurements is commutative, however the Poisson bracket allows noncommutativity to be added naturally. After we introduce noncommutativity into classical measurement theory, we can also add quantum noise, differentiated from thermal noise by Poincar\’e invariance. With these two changes, the extended classical and quantum measurement theories are equally capable, so we may speak of a single “measurement theory”. The reconciliation of general relativity and quantum theory has been long delayed because classical and quantum systems have been thought to be very different, however this unification allows us to discuss a unified measurement theory for geometry in physics.

上午10:15 | | | Rikizo Ikuta | | | quant-ph updates on arXiv.org |

We show a wave-particle duality of light and its complementary relation in the context of the intensity interference measured by intensity correlation measurement, especially for the case of the second-order intensity interference observed in the Hong-Ou-Mandel interferometer. Different from the complementary relation appearing in the interference based on the phase coherence like in the Young’s double-slit interferometer, the complementary relation in the intensity interference has a gap between classical and nonclassical lights. This reveals a new nonclassical nature of light where both wave and particle properties are classically understandable. We further extend the wave-particle duality and the complementarity to higher-order intensity interferometric situations.

Towards real-world quantum networks: a review. (arXiv:2201.04802v1 [quant-ph])

上午10:15 | | | Shi-Hai Wei, Bo Jing, Xue-Ying Zhang, Jin-Yu Liao, Chen-Zhi Yuan, Bo-Yu Fan, Chen Lyu, Dian-Li Zhou, You Wang, Guang-Wei Deng, Hai-Zhi Song, Daniel Oblak, Guang-Can Guo, Qiang Zhou | | | quant-ph updates on arXiv.org |

Quantum networks play an extremely important role in quantum information science, with application to quantum communication, computation, metrology and fundamental tests. One of the key challenges for implementing a quantum network is to distribute entangled flying qubits to spatially separated nodes, at which quantum interfaces or transducers map the entanglement onto stationary qubits. The stationary qubits at the separated nodes constitute quantum memories realized in matter while the flying qubits constitute quantum channels realized in photons. Dedicated efforts around the world for more than twenty years have resulted in both major theoretical and experimental progress towards entangling quantum nodes and ultimately building a global quantum network. Here, we review the development of quantum networks and the experimental progress over the past two decades leading to the current state of the art for generating entanglement of quantum nodes based on various physical systems such as single atoms, cold atomic ensembles, trapped ions, diamonds with Nitrogen-Vacancy centers, solid-state host doped with rare-earth ions, etc. Along the way we discuss the merits and compare the potential of each of these systems towards realizing a quantum network.

Fundamental limits of superconducting quantum computers. (arXiv:2201.05114v1 [quant-ph])

上午10:15 | | | Michele Vischi, Luca Ferialdi, Andrea Trombettoni, Angelo Bassi | | | quant-ph updates on arXiv.org |

The Continuous Spontaneous Localization (CSL) model is an alternative formulation of quantum mechanics which introduces a noise coupled non linearly to the wave function to account for its collapse. We consider CSL effects on quantum computers made of superconducting transmon qubits. As a direct effect CSL reduces quantum superpositions of the computational basis states of the qubits: we show the reduction rate to be negligibly small. However, an indirect effect of CSL, dissipation induced by the noise, also leads transmon qubits to decohere, by generating additional quasiparticles. Since the decoherence rate of transmon qubits depends on the quasiparticle density, by computing their generation rate induced by CSL, we can estimate the corresponding quasiparticle density and thus the limit set by CSL on the performances of transmon quantum computers. We show that CSL could spoil the quantum computation of practical algorithms on large devices. We further explore the possibility of testing CSL effects on superconducting devices.

上午10:15 | | | Andreas Fring | | | quant-ph updates on arXiv.org |

I will provide a pedagogical introduction to non-Hermitian quantum systems that are PT-symmetric, that is they are left invariant under a simultaneous parity transformation (P) and time-reversal (T). I will explain how generalised versions of this antilinear symmetry can be utilised to explain that these type of systems possess real eigenvalue spectra in parts of their parameter spaces and how to set up a consistent quantum mechanical framework for them that enables a unitary time-evolution. In the second part I will explain how to extend this framework to explicitly time-dependent Hamiltonian systems and report in particular on recent progress made in this context. I will explain how to construct the essential key quantity in this framework, the time-dependent Dyson map and metric and solutions to the time-dependent Schr\”odinger equation, in an algebraic fashion, using time-dependent Darboux transformations, utilising Lewis-Riesenfeld invariants, point transformations and some approximation methods. I comment on the ambiguities of this metric and demonstrate that this can even lead to infinite series of metric operators. I conclude with some applications to PT-symmetrically coupled oscillators, demonstrate the equivalence of the time-dependent double wells and unstable anharmonic oscillators and show how the unphysical PT$-symmetrically broken regions in the parameter space for the time-independent theory becomes physical in the explicitly time-dependent systems. I discuss how this leads to a prolongation of the otherwise rapidly decaying von Neumann entropy. The so-called sudden death of the entropy is stopped at a finite value.

Consensus between Epistemic Agents is Difficult. (arXiv:2201.04642v1 [physics.soc-ph])

上午10:15 | | | physics.hist-ph updates on arXiv.org |

Authors: Damian R. Sowinski, Jonathan Carroll-Nellenback, Jeremy M. DeSilva, Adam Frank, Gourab Ghoshal, Marcelo Gleiser, Hari Seldon

We introduce an epistemic information measure between two data streams, that we term $influence$. Closely related to transfer entropy, the measure must be estimated by epistemic agents with finite memory resources via sampling accessible data streams. We show that even under ideal conditions, epistemic agents using slightly different sampling strategies might not achieve consensus in their conclusions about which data stream is influencing which. As an illustration, we examine a real world data stream where different sampling strategies result in contradictory conclusions, explaining why some politically charged topics might exist due to purely epistemic reasons irrespective of the actual ontology of the world.

On the Consilience between QBism and Phenomenology. (arXiv:2201.04734v1 [quant-ph])

上午10:15 | | | physics.hist-ph updates on arXiv.org |

Authors: Hans Christian von Baeyer

Two decades after its creation, the interpretation of quantum mechanics called QBism is entering a new phase. Since it shares a personalist, subjective world-view with phenomenology, the philosophical study of human experience, there is a growing interest in the relationship between the two subjects. I call attention to the little-known philosopher Samuel Todes, whose phenomenology focused on the essential role of the human body in our understanding of the world. After reviewing this radical proposal, and illustrating it with some examples, I recommend it as an interesting mediator between the communities of physicists and phenomenologists. In addition, I argue that it may prove useful for promoting the public understanding of QBism.

Chris Isham: mentor, colleague, friend. (arXiv:2112.13722v2 [physics.hist-ph] UPDATED)

上午10:15 | | | physics.hist-ph updates on arXiv.org |

Authors: M. J. Duff

Celebrating fifty years of collaboration and friendship with Chris Isham.

Symmetries Near the Horizon. (arXiv:1904.12820v2 [hep-th] UPDATED)

上午10:15 | | | gr-qc updates on arXiv.org |

Authors: Henry W. Lin, Juan Maldacena, Ying Zhao

We consider a nearly-AdS$_2$ gravity theory on the two-sided wormhole geometry. We construct three gauge-invariant operators in NAdS which move bulk matter relative to the dynamical boundaries. In a two-sided system, these operators satisfy an SL(2) algebra (up to non-perturbative corrections). In a semiclassical limit, these generators act like SL(2) transformations of the boundary time, or conformal symmetries of the two sided boundary theory. These can be used to define an operator-state mapping. A particular large N and low temperature limit of the SYK model has precisely the same structure, and this construction of the exact generators also applies. We also discuss approximate, but simpler, constructions of the generators in the SYK model. These are closely related to the “size” operator and are connected to the maximal chaos behavior captured by out of time order correlators.

Can dark energy emerge from a varying $G$ and spacetime geometry?. (arXiv:2201.04629v1 [gr-qc])

上午10:15 | | | gr-qc updates on arXiv.org |

Authors: Ekim Taylan Hanımeli, Isaac Tutusaus, Brahim Lamine, Alain Blanchard

The accelerated expansion of the Universe implies the existence of an energy contribution known as dark energy. Associated with the cosmological constant in the standard model of cosmology, the nature of this dark energy is still unknown. We will discuss an alternative gravity model in which this dark energy contribution emerges naturally, as a result of allowing for a time-dependence on the gravitational constant, $G$, in Einstein’s Field Equations. With this modification, Bianchi’s identities require an additional tensor field to be introduced so that the usual conservation equation for matter and radiation is satisfied. The equation of state of this tensor field is obtained using additional constraints, coming from the assumption that this tensor field represents the space-time response to the variation of $G$. We will also present the predictions of this model for the late-Universe data, and show that the energy contribution of this new tensor is able to explain the accelerated expansion of the Universe without the addition of a cosmological constant. Unlike many other alternative gravities with varying gravitational strength, the predicted $G$ evolution is also consistent with local observations and therefore this model does not require screening. We will finish by discussing possible other implications this approach might have for cosmology and some future prospects.

The Road to Precision Cosmology. (arXiv:2201.04741v1 [astro-ph.CO])

上午10:15 | | | gr-qc updates on arXiv.org |

Authors: Michael S. Turner

The past 50 years has seen cosmology go from a field known for the errors being in the exponents to precision science. The transformation, powered by ideas, technology, a paradigm shift and culture change, has revolutionized our understanding of the Universe, with the $\Lambda$CDM paradigm as its crowning achievement. I chronicle the journey of precision cosmology and finish with my thoughts about what lies ahead.

A quantum state for the late Universe. (arXiv:2108.05111v2 [gr-qc] UPDATED)

上午10:15 | | | gr-qc updates on arXiv.org |

Authors: Andrea Giusti, Silvia Buffa, Lavinia Heisenberg, Roberto Casadio

We consider the quantum description of a toy model universe in which the Schwarzschild-de Sitter geometry emerges from the coherent state of a massless scalar field. Although highly idealised, this simple model allows us to find clear hints supporting the conclusion that the reaction of the de Sitter background to the presence of matter sources induces i) a modified Newtonian dynamics at galactic scales and ii) different values measured for the present Hubble parameter. Both effects stem from the conditions required to have a normalisable quantum state.

上午10:15 | | | gr-qc updates on arXiv.org |

Authors: Shammi Tahura, Zhen Pan, Huan Yang

It has been suggested that there is possibly a class of stellar-mass black holes (BHs) residing near (distance $\le 10^3 M$) the galactic center massive black hole, Sgr A*. Possible formation scenarios include the mass segregation of massive stellar-mass black holes and/or the disk migration if there was an active accretion flow near Sgr A* within $\mathcal{O}(10)$ Myr. In this work, we explore the application of this type of objects as sources of space-borne gravitational wave detectors, such as Laser Interferometer Space Antenna (LISA). We find it is possible to probe the spin of Sgr A* based on the precession of the orbital planes of these stellar-mass black holes moving around Sgr A*. We also show that the dynamical friction produced by accumulated cold dark matter near Sgr A* generally produces small measurable phase shift in the gravitational waveform. In the case that there is an axion cloud near Sgr A*, the dynamical friction induced modification to gravitational waveform is measurable only if the mass of the axion field is in a narrow range of the mass spectrum. Gravitational interaction between the axion cloud and the stellar-mass black holes may introduce additional precession around the spin of Sgr A*. This additional precession rate is generally weaker than the spin-induced Lense-Thirring precession rate, but nevertheless may contaminate the spin measurement in a certain parameter regime. At last, we point out that the multi-body gravitational interaction between these stellar-mass black holes generally causes negligible phase shift during the LISA lifetime.

2022年1月13日 星期四 上午8:00 | | | Mark Buchanan | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 13 January 2022; doi:10.1038/s41567-021-01484-w

Pinning down the proton

Free Energy Pragmatics: Markov blankets don’t prescribe objective ontology, and that’s okay

2022年1月11日 星期二 下午5:43 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hipolito, Ines and va es, Thomas (2022) Free Energy Pragmatics: Markov blankets don’t prescribe objective ontology, and that’s okay. [Preprint]

On Two Different Kinds of Computational Indeterminacy

2022年1月11日 星期二 下午5:43 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Papayannopoulos, Philippos and Fresco, Nir and Shagrir, Oron (2021) On Two Different Kinds of Computational Indeterminacy. [Preprint]

Detecting Entanglement Structure in Continuous Many-Body Quantum Systems

2022年1月10日 星期一 下午6:00 | | | Philipp Kunkel, Maximilian Prüfer, Stefan Lannig, Robin Strohmaier, Martin Gärttner, Helmut Strobel, and Markus K. Oberthaler | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Philipp Kunkel, Maximilian Prüfer, Stefan Lannig, Robin Strohmaier, Martin Gärttner, Helmut Strobel, and Markus K. Oberthaler

A prerequisite for the comprehensive understanding of many-body quantum systems is a characterization in terms of their entanglement structure. The experimental detection of entanglement in spatially extended many-body systems describable by quantum fields still presents a major challenge. We develo…

[Phys. Rev. Lett. 128, 020402] Published Mon Jan 10, 2022

Wavefunction Realism Does Not ‘Privilege Position’

2022年1月8日 星期六 下午5:44 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Schroeren, David (2021) Wavefunction Realism Does Not ‘Privilege Position’. [Preprint]

2022年1月8日 星期六 下午5:40 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Katzav, Joel and Vaesen, Krist (2022) The rise of logical empiricist philosophy of science and the fate of speculative philosophy of science. [Preprint]

QBISM: AN ECO-PHENOMENOLOGY OF QUANTUM PHYSICS

2022年1月8日 星期六 下午5:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Bitbol, Michel and De la Tremblaye, Laura (2022) QBISM: AN ECO-PHENOMENOLOGY OF QUANTUM PHYSICS. [Preprint]

Brownian motion from a deterministic system of particles

2022年1月8日 星期六 下午5:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Ardourel, Vincent (2022) Brownian motion from a deterministic system of particles. [Preprint]

Particles in Quantum Field Theory

2022年1月8日 星期六 下午5:37 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Fraser, Doreen (2017) Particles in Quantum Field Theory. [Preprint]

]]>上午9:51 | | | Arnold Neumaier | | | quant-ph updates on arXiv.org |

Starting from a new basic principle inspired by quantum tomography rather than from Born’s rule, this paper gives an elementary, and self-contained deductive approach to quantum mechanics and quantum measurement. A suggestive notion for what constitutes a quantum detector and for the behavior of its responses leads to a logically impeccable definition of measurement. Applications to measurement schemes for optical states, position measurements and particle tracks demonstrate that this definition is applicable to complex realistic experiments without any idealization.

The various forms of quantum tomography for quantum states, quantum detectors, quantum processes, and quantum instruments are discussed. The traditional dynamical and spectral properties of quantum mechanics are derived from a continuum limit of quantum processes. In particular, the Schr\”odinger equation for the state vector of a pure, nonmixing quantum system and the Lindblad equation for the density operator of a mixing quantum system are shown to be consequences of the new approach. Normalized density operators are shown to play the role of quantum phase space variables, in complete analogy to the classical phase space variables position and momentum. A slight idealization of the measurement process leads to the notion of quantum fields, whose smeared quantum expectations emerge as reproducible properties of regions of space accessible to measurements.

A variety of quotes from the literature illuminate the formal exposition with historical and philosophical aspects.

上午9:51 | | | G. L. Klimchitskaya, V. M. Mostepanenko | | | quant-ph updates on arXiv.org |

It has been known that the Lifshitz theory of the Casimir force comes into conflict with the measurement data if the response of conduction electrons in metals to electromagnetic fluctuations is described by the well tested dissipative Drude model. The same theory is in a very good agreement with measurements of the Casimir force from graphene whose spatially nonlocal electromagnetic response is derived from the first principles of quantum electrodynamics. Here, we propose the spatially nonlocal phenomenological dielectric functions of metals which lead to nearly the same response, as the standard Drude model, to the propagating waves, but to a different response in the case of evanescent waves. Unlike some previous suggestions of this type, the response functions considered here depend on all components of the wave vector as is most natural in the formalism of specular reflection used. It is shown that these response functions satisfy the Kramers-Kronig relations. We derive respective expressions for the surface impedances and reflection coefficients. The obtained results are used to compute the effective Casimir pressure between two parallel plates, the Casimir force between a sphere and a plate, and its gradient in configurations of the most precise experiments performed with both nonmagnetic (Au) and magnetic (Ni) test bodies. It is shown that in all cases (Au-Au, Au-Ni, and Ni-Ni test bodies) the predictions of the Lifshitz theory found by using the dissipative nonlocal response functions are in as good agreement with the measurement data, as was reached previously with the dissipationless plasma model. Possible developments and applications of these results are discussed.

上午9:51 | | | S. A. Lyon (1), Kyle Castoria (1), Ethan Kleinbaum (1), Zhihao Qin (2), Arun Persaud (2), Thomas Schenkel (2), Kathryn Zurek (3) ((1) Princeton University, (2) Lawrence Berkeley National Lab, (3) California Institute of Technology) | | | quant-ph updates on arXiv.org |

Dark matter is five times more abundant than ordinary visible matter in our Universe. While laboratory searches hunting for dark matter have traditionally focused on the electroweak scale, theories of low mass hidden sectors motivate new detection techniques. Extending these searches to lower mass ranges, well below 1 GeV/c$^2$, poses new challenges as rare interactions with standard model matter transfer progressively less energy to electrons and nuclei in detectors. Here, we propose an approach based on phonon-assisted quantum evaporation combined with quantum sensors for detection of desorption events via tracking of spin coherence. The intent of our proposed dark matter sensors is to extend the parameter space to energy transfers in rare interactions to as low as a few meV for detection of dark matter particles in the keV/c$^2$ mass range.

Time as Change. (arXiv:2201.01944v1 [physics.hist-ph])

上午9:51 | | | physics.hist-ph updates on arXiv.org |

Authors: Marcello Poletti

According to Aristotle “time is the number of change with respect to the before and after”. That’s certainly a vague concept, but at the same time it’s both simple and satisfying from a philosophical point of view: things do not change along time, but they do change and the measurement of such changes is what we call time. This deprives time of any attribute of substantiality, meanwhile depriving it of all problems in defining the properties of time as a substance. With the rise of Classical Mechanics, Aristotle’s view is abandoned and Newton’s concept of “true” and absolute time imposes itself; time flows independently on changes of any kind. Relativity will then radically modify our concept of time, but won’t actually modify the fundamental idea: things keep changing along time — changes do not make time. This work will argue Aristotle’s thesis, showing how such an approach automatically leads to the principles of Special Relativity. An interesting consequence and, at least virtually, measurable will also be highlighted: the fact that synchronizing two clocks with a precision greater than a certain scale is impossible, estimating such scale around $10^{-22}$s.

上午9:51 | | | ScienceDirect Publication: Physics ReportsScienceDirect RSShttps://www.sciencedirect.com/journal/physics-reportsRSS for NodeTue, 23 Jul 2019 10:02:48 GMTCopyright © 2019 Elsevier B.V. All rights reservedRapid solidification as non-ergodic phenomenonPublication date: 20 July 2019Source: Physics Reports, Volume 818Author(s): P.K. Galenko, D. JouAbstractRapid solidification is a relevant physical phenomenon in material sciences, whose theoretical analysis requires going beyond the limits of local equilibrium statistical physics and thermodynamics and, in particular, taking account of ergodicity breaking and of generalized formulation of thermodynamics. The ergodicity breaking is related to the time symmetry breaking and to the presence of some kinds of fluxes and gradient flows making that an average of microscopic variables along time is different than an average over some chosen statistical ensemble. In fast processes, this is due, for instance, to the fact that the system has no time enough to explore the who |

Publication date: 11 March 2022

**Source:** Physics Reports, Volume 951

Author(s): Alessio Belenchia, Matteo Carlesso, Ömer Bayraktar, Daniele Dequal, Ivan Derkach, Giulio Gasbarri, Waldemar Herr, Ying Lia Li, Markus Rademacher, Jasminder Sidhu, Daniel K.L. Oi, Stephan T. Seidel, Rainer Kaltenbaek, Christoph Marquardt, Hendrik Ulbricht, Vladyslav C. Usenko, Lisa Wörner, André Xuereb, Mauro Paternostro, Angelo Bassi

Thermodynamically consistent entropic-force cosmology. (arXiv:2201.01835v1 [gr-qc])

上午9:51 | | | gr-qc updates on arXiv.org |

Authors: D. J. Zamora, C. Tsallis

We analyze the thermodynamical consistency of entropic-force cosmological models. Our analysis is based on a generalized entropy scaling with an arbitrary power of the Hubble radius. The Bekenstein-Hawking entropy, proportional to the area, and the nonadditive $S_{\delta=3/2}$-entropy, proportional to the volume, are particular cases. One of the points to be solved by entropic-force cosmology for being taken as a serious alternative to mainstream cosmology is to provide a physical principle that points out what entropy and temperature have to be used. We determine the temperature of the universe horizon by requiring that the Legendre structure of thermodynamics is preserved. We compare the performance of thermodynamically consistent entropic-force models with regard to the available supernovae data by providing appropriate constraints for optimizing alternative entropies and temperatures of the Hubble screen. Our results point out that the temperature differs from the Hawking one.

Cosmological constant problem on the horizon. (arXiv:2201.02016v1 [gr-qc])

上午9:51 | | | gr-qc updates on arXiv.org |

Authors: Hassan Firouzjahi

We revisit the quantum cosmological constant problem and highlight the important roles played by the dS horizon of zero point energy. We argue that fields which are light enough to have dS horizon of zero point energy comparable to the FLRW Hubble radius are the main contributor to dark energy. On the other hand, the zero point energy of heavy fields develop nonlinearities on sub-Hubble scales and can not contribute to dark energy. Our proposal provides a simple resolution for both the old and new cosmological constant problems by noting that there exits a field, the (lightest) neutrino, which happens to have a mass comparable to the present background photon temperature. The natures of dark energy and dark matter are unified in this proposal in which the zero point energy of light fields are the source of dark energy while dark matter is sourced by the zero point energy of heavy fields. The proposal predicts multiple transient periods of dark energy in early and late expansion history of the universe yielding to a higher value of the current Hubble expansion rate which can resolve the $H_0$ tension problem.

2022年1月7日 星期五 下午6:00 | | | Alejandro Pozas-Kerstjens, Nicolas Gisin, and Armin Tavakoli | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Alejandro Pozas-Kerstjens, Nicolas Gisin, and Armin Tavakoli

Networks have advanced the study of nonlocality beyond Bell’s theorem. Here, we introduce the concept of full network nonlocality, which describes correlations that necessitate all links in a network to distribute nonlocal resources. Showcasing that this notion is stronger than standard network nonl…

[Phys. Rev. Lett. 128, 010403] Published Fri Jan 07, 2022

Thermodynamic Stability Implies Causality

2022年1月6日 星期四 下午6:00 | | | L. Gavassino, M. Antonelli, and B. Haskell | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): L. Gavassino, M. Antonelli, and B. Haskell

The stability conditions of a relativistic hydrodynamic theory can be derived directly from the requirement that the entropy should be maximized in equilibrium. Here, we use a simple geometrical argument to prove that, if the hydrodynamic theory is stable according to this entropic criterion, then l…

[Phys. Rev. Lett. 128, 010606] Published Thu Jan 06, 2022

2022年1月4日 星期二 下午5:39 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Kirchhoff, Michael and Kiverstein, Julian and Robertson, Ian (2022) The Literalist Fallacy & the Free Energy Principle: Model-building, Scientific Realism and Instrumentalism. [Preprint]

The ~In~Determinacy of Computation

2022年1月4日 星期二 下午5:35 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Curtis-Trudel, Andre E (2022) The ~In~Determinacy of Computation. [Preprint]

]]>上午9:11 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Bach, Theodore (2019) Why the Empirical Study of Non-Philosophical Expertise Does Not Undermine the Status of Philosophical Expertise. Erkenntnis, 86 (4). pp. 999-1023.

上午9:11 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Linnemann, Niels and Read, James (2021) Constructive Axiomatics in Spacetime Physics Part I: Walkthrough to the Ehlers-Pirani-Schild Axiomatisation. [Preprint]

Time Division Multiverse: A New Picture of Quantum Reality

上午9:10 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gao, Shan (2021) Time Division Multiverse: A New Picture of Quantum Reality. [Preprint]

Quantum Simulation of Open Quantum Systems Using a Unitary Decomposition of Operators

2021年12月29日 星期三 下午6:00 | | | Anthony W. Schlimgen, Kade Head-Marsden, LeeAnn M. Sager, Prineha Narang, and David A. Mazziotti | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Anthony W. Schlimgen, Kade Head-Marsden, LeeAnn M. Sager, Prineha Narang, and David A. Mazziotti

Electron transport in realistic physical and chemical systems often involves the nontrivial exchange of energy with a large environment, requiring the definition and treatment of open quantum systems. Because the time evolution of an open quantum system employs a nonunitary operator, the simulation …

[Phys. Rev. Lett. 127, 270503] Published Wed Dec 29, 2021

2021年12月28日 星期二 下午12:58 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Martens, Niels C.M. (2022) Dark Matter Realism. Foundations of Physics, 52 (1). ISSN 0015-9018

Quantum Gravity at Low Energies

2021年12月28日 星期二 下午12:57 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wallace, David (2021) Quantum Gravity at Low Energies. [Preprint]

Stating structural realism: mathematics-first approaches to physics and metaphysics

2021年12月28日 星期二 下午12:56 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wallace, David (2021) Stating structural realism: mathematics-first approaches to physics and metaphysics. [Preprint]

Analogy and Composition in Early Nineteenth-Century Chemistry: The Case of Aluminium

2021年12月28日 星期二 下午12:55 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hijmans, Sarah (2021) Analogy and Composition in Early Nineteenth-Century Chemistry: The Case of Aluminium. [Preprint

No Preferred Reference Frame at the Foundation of Quantum Mechanics

William Stuckey , Timothy McDevitt and Michael Silberstein

Quantum information theorists have created axiomatic reconstructions of quantum mechanics (QM) that are very successful at identifying precisely what distinguishes quantum probability theory from classical and more general probability theories in terms of information-theoretic principles. Herein, we show how one such principle, Information Invariance and Continuity, at the foundation of those axiomatic reconstructions, maps to “no preferred reference frame” (NPRF, aka “the relativity principle”) as it pertains to the invariant measurement of Planck’s constant h for Stern-Gerlach (SG) spin measurements. This is in exact analogy to the relativity principle as it pertains to the invariant measurement of the speed of light c at the foundation of special relativity (SR). Essentially, quantum information theorists have extended Einstein’s use of NPRF from the boost invariance of measurements of c to include the SO(3) invariance of measurements of h between different reference frames of mutually complementary spin measurements via the principle of Information Invariance and Continuity. Consequently, the “mystery” of the Bell states is understood to result from conservation per Information Invariance and Continuity between different reference frames of mutually complementary qubit measurements, and this maps to conservation per NPRF in spacetime. If one falsely conflates the relativity principle with the classical theory of SR, then it may seem impossible that the relativity principle resides at the foundation of non-relativisitic QM. In fact, there is nothing inherently classical or quantum about NPRF. Thus, the axiomatic reconstructions of QM have succeeded in producing a principle account of QM that reveals as much about Nature as the postulates of SR.

A No-go Theorem for Psi-anomic Models under the Restricted Ontic Indifference Assumption

Aurelien Drezet

We address the question of whether a non-nomological (i.e., anomic) interpretation of the wavefunction is compatible with the quantum formalism. After clarifying the distinction between ontic, epistemic, nomic and anomic models we focus our attention on two famous no-go theorems due to Pusey, Barrett, and Rudolph (PBR) on the one side and Hardy on the other side which forbid the existence of anomic-epistemic models. Moreover, we demonstrate that the so called restricted ontic indifference introduced by Hardy induces new constraints. We show that after modifications the Hardy theorem actually rules out all anomic models of the wavefunction assuming only restricted ontic indifference and preparation independence.

]]>We address the question of whether a non-nomological (i.e., anomic) interpretation of the wavefunction is compatible with the quantum formalism. After clarifying the distinction between ontic, epistemic, nomic and anomic models we focus our attention on two famous no-go theorems due to Pusey, Barrett, and Rudolph (PBR) on the one side and Hardy on the other side which forbid the existence of anomic-epistemic models. Moreover, we demonstrate that the so called restricted ontic indifference introduced by Hardy induces new constraints. We show that after modifications the Hardy theorem actually rules out all anomic models of the wavefunction assuming only restricted ontic indifference and preparation independence.

]]>Yoko Suzuki and Kevin M Mertes

We introduce a new interpretation of quantum mechanics by examining the Einstein, Podolsky and Rosen (EPR) paradox and Bell’s inequality experiments under the assumption that the vacuum fluctuation has a locally varying texture (a local variable) for energy levels below the Heisenberg time-energy uncertainty relation. In this article, selected results from the most reliable Bell’s inequality experiments will be quantitatively analyzed to show that our interpretation of quantum mechanics creates a new loophole in Bell’s inequality, and that the past experimental findings do not contradict our new interpretation. Under the vacuum texture interpretation of quantum mechanics in a Bell’s inequality experiment, the states of the pair of particles created at the source (e.g. during parametric down conversion) is influenced by an inhomogeneous vacuum texture sent with the speed of light from the measurement apparatus. We will also show that the resulting pair of particles are not entangled and that the theory of vacuum texture preserves local realism with complete causality. This article will also suggest an experiment to definitively confirm the existence of vacuum texture.

]]>上午9:40 | | | Johanna Erdmenger, Mario Flory, Marius Gerbershagen, Michal P. Heller, Anna-Lena Weigel | | | quant-ph updates on arXiv.org |

Holographic complexity proposals have sparked interest in quantifying the cost of state preparation in quantum field theories and its possible dual gravitational manifestations. The most basic ingredient in defining complexity is the notion of a class of circuits that, when acting on a given reference state, all produce a desired target state. In the present work we build on studies of circuits performing local conformal transformations in general two-dimensional conformal field theories and construct the exact gravity dual to such circuits. In our approach to holographic complexity, the gravity dual to the optimal circuit is the one that minimizes an externally chosen cost assigned to each circuit. Our results provide a basis for studying exact gravity duals to circuit costs from first principles.

上午9:40 | | | Decheng Ma, Chenglong Jia, Enrique Solano, Lucas Chibebe Céleri | | | quant-ph updates on arXiv.org |

We consider acoustic propagation of phonons in the presence of a non-rotating vortex with radial flow in a Bose-Einstein condensate (BEC) of photons. Since the vortex can be used to simulate a static acoustic black hole, the phonon would experience a considerable spacetime curvature at appreciable distance from the vortex core. The trajectory of the phonons is bended after passing by the vortex, which can be used as a simulation of gravitational lensing for phonons in a photonic BEC.

Comments on the Aharonov-Bohm Effect. (arXiv:2112.11171v2 [quant-ph] UPDATED)

上午9:40 | | | Kazuyasu Shigemoto, Kunihiko Uehara | | | quant-ph updates on arXiv.org |

In the original setting of the Aharonov-Bohm, the gauge invariant physical longitudinal mode of the vector potential, which is written by the gauge invariant physical current $(-e)\bar{\psi}{\boldsymbol \gamma} \psi$, gives the desired contribution to the Aharonov-Bohm effect. While the scalar mode of the vector potential, which changes under the gauge transformation so that it is the unphysical mode, give no contribution to the Aharonov-Bohm effect. Then Aharonov-Bohm effect really occurs by the physical longitudinal mode in the original Aharonov-Bohm’s setting. In the setting of Tonomura {\it et al.}, where the magnet is shielded with the superconducting material, not only the magnetic field but also the longitudinal mode of the vector potential become massive by the Meissner effect. Then not only the magnetic field but also the physical longitudinal mode does not come out to the region where the electron travels. In such setting, only the scalar mode of the vector potential exists in the region where the electron travels, but there is no contribution to the Aharonov-Bohm effect from that mode. Then, theoretically, the Aharonov-Bohm effect does not occur in the Tonomura {\it et al.}’s setting. In the quantum theory, the electron is treated as the wave, and the longitudinal mode give the change of the phase, which gives the Aharonov-Bohm effect. In the classical theory, the electron is treated as the particle, and the only existing longitudinal mode gives the change of the angular momentum. For the particle, there is no concept of the phase, so that there is no Aharonov-Bohm effect.

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

Authors: P.D. Gujrati

Using classical thermodynamics, we argue that Maxwell’s demon loses its battle against Clausius as any temperature difference or other thermodynamic forces it creates is immediately compensated by spontaneous counterbalancing flows that bring about equilibration by slower particles in principle. Being constrained by these spontaneously generated equilibration processes in which he actively but unwittingly participates, the demon is incapable of destroying equilibrium and violating the second law. In fact, our investigation shows that he is unintentionally designed to support it, and does not alter the temperature.

Precision tests of fundamental physics with η and η′ mesons

上午9:40 | | | ScienceDirect Publication: Physics ReportsScienceDirect RSShttps://www.sciencedirect.com/journal/physics-reportsRSS for NodeTue, 23 Jul 2019 10:02:48 GMTCopyright © 2019 Elsevier B.V. All rights reservedRapid solidification as non-ergodic phenomenonPublication date: 20 July 2019Source: Physics Reports, Volume 818Author(s): P.K. Galenko, D. JouAbstractRapid solidification is a relevant physical phenomenon in material sciences, whose theoretical analysis requires going beyond the limits of local equilibrium statistical physics and thermodynamics and, in particular, taking account of ergodicity breaking and of generalized formulation of thermodynamics. The ergodicity breaking is related to the time symmetry breaking and to the presence of some kinds of fluxes and gradient flows making that an average of microscopic variables along time is different than an average over some chosen statistical ensemble. In fast processes, this is due, for instance, to the fact that the system has no time enough to explore the who |

Publication date: 26 January 2022

**Source:** Physics Reports, Volume 945

Author(s): Liping Gan, Bastian Kubis, Emilie Passemar, Sean Tulin

Emergent times in holographic duality. (arXiv:2112.12156v1 [hep-th])

上午9:40 | | | gr-qc updates on arXiv.org |

Authors: Samuel Leutheusser, Hong Liu

In holographic duality an eternal AdS black hole is described by two copies of the boundary CFT in the thermal field double state. In this paper we provide explicit constructions in the boundary theory of infalling time evolutions which can take bulk observers behind the horizon. The constructions also help to illuminate the boundary emergence of the black hole horizons, the interiors, and the associated causal structure. A key element is the emergence, in the large $N$ limit of the boundary theory, of a type III$_1$ von Neumann algebraic structure from the type I boundary operator algebra and the half-sided modular translation structure associated with it.

Quantum Gravity at Low Energies. (arXiv:2112.12235v1 [gr-qc])

上午9:40 | | | gr-qc updates on arXiv.org |

Authors: David Wallace

I provide a conceptually-focused presentation of `low-energy quantum gravity’ (LEQG), the effective quantum field theory obtained from general relativity and which provides a well-defined theory of quantum gravity at energies well below the Planck scale. I emphasize the extent to which some such theory is required by the abundant observational evidence in astrophysics and cosmology for situations which require a simultaneous treatment of quantum-mechanical and gravitational effects, \emph{contra} the often-heard claim that all observed phenomena can be accounted for either by classical gravity or by non-gravitational quantum mechanics, and I give a detailed account of the way in which a treatment of the theory as fluctuations on a classical background emerges as an approximation to the underlying theory rather than being put in by hand. I discuss the search for a Planck-scale quantum-gravity theory from the perspective of LEQG and give an introduction to the Cosmological Constant problem as it arises within LEQG.

A Measurement of the Cosmic Expansion Within our Lifetime. (arXiv:2112.12599v1 [gr-qc])

上午9:40 | | | gr-qc updates on arXiv.org |

Authors: Fulvio Melia

The most exciting future observation in cosmology will feature a monitoring of the cosmic expansion in real time, unlike anything that has ever been attempted before. This campaign will uncover crucial physical properties of the various constituents in the Universe, and perhaps answer a simpler question concerning whether or not the cosmic expansion is even accelerating. An unambiguous yes/no response to this query will significantly impact cosmology, of course, but also the standard model of particle physics. Here, we discuss — in a straightforward way — how to understand the so-called `redshift drift’ sought by this campaign, and why its measurement will help us refine the standard-model parameters if the answer is `yes.’ A `no’ answer, on the other hand, could be more revolutionary, in the sense that it might provide a resolution of several long-standing problems and inconsistencies in our current cosmological models. An outcome of zero redshift drift, for example, would obviate the need for a cosmological constant and render inflation completely redundant.

上午9:40 | | | gr-qc updates on arXiv.org |

Authors: Robert B. Mann, Sebastian Murk, Daniel R. Terno

The information loss paradox is widely regarded as one of the biggest open problems in theoretical physics. Several classical and quantum features must be present to enable its formulation. First, an event horizon is needed to justify the objective status of tracing out degrees of freedom inside the black hole. Second, evaporation must be completed (or nearly completed) in finite time according to a distant observer, and thus the formation of the black hole should also occur in finite time. In spherical symmetry these requirements constrain the possible metrics strongly enough to obtain a unique black hole formation scenario and match their parameters with the semiclassical results. However, the two principal generalizations of surface gravity, the quantity that determines the Hawking temperature, do not agree with each other on the dynamic background. Neither can correspond to the emission of nearly-thermal radiation. We infer from this that the information loss problem cannot be posed in its standard form.

上午9:40 | | | gr-qc updates on arXiv.org |

Authors: Renato Renner, Jinzhao Wang

The black hole information puzzle arises from a discrepancy between conclusions drawn from general relativity and quantum theory about the nature of the radiation emitted by a black hole. According to Hawking’s original argument, the radiation is thermal and its entropy thus increases monotonically as the black hole evaporates. Conversely, due to the reversibility of time evolution according to quantum theory, the radiation entropy should start to decrease after a certain time, as predicted by the Page curve. This decrease has been confirmed by new calculations based on the replica trick, which also exhibit its geometrical origin: spacetime wormholes that form between the replicas. Here we analyse the discrepancy between these and Hawking’s original conclusions from a quantum information theory viewpoint, using in particular the quantum de Finetti theorem. The theorem implies the existence of extra information, $W$, which is neither part of the black hole nor the radiation, but plays the role of a reference. The entropy obtained via the replica trick can then be identified to be the entropy $S(R|W)$ of the radiation conditioned on the reference $W$, whereas Hawking’s original result corresponds to the non-conditional entropy $S(R)$. The entropy $S(R|W)$, which mathematically is an ensemble average, gains an operational meaning in an experiment with $N$ independently prepared black holes: For large $N$, it equals the normalised entropy of their joint radiation, $S(R_1 \cdots R_N)/N$. The discrepancy between this entropy and $S(R)$ implies that the black holes are correlated. The replica wormholes may thus be interpreted as the geometrical representation of this correlation. Our results also suggest a many-black-hole extension of the widely used random unitary model, which we support with non-trivial checks.

上午9:40 | | | gr-qc updates on arXiv.org |

Authors: Robert B. Mann, Sebastian Murk, Daniel R. Terno

For distant observers black holes are trapped spacetime domains bounded by apparent horizons. We review properties of the near-horizon geometry emphasizing the consequences of two common implicit assumptions of semiclassical physics. The first is a consequence of the cosmic censorship conjecture, namely that curvature scalars are finite at apparent horizons. The second is that horizons form in finite asymptotic time (i.e. according to distant observers), a property implicitly assumed in conventional descriptions of black hole formation and evaporation. Taking these as the only requirements within the semiclassical framework, we find that in spherical symmetry only two classes of dynamic solutions are admissible, both describing evaporating black holes and expanding white holes. We review their properties and present the implications. The null energy condition is violated in the vicinity of the outer and satisfied in the vicinity of the inner apparent/anti-trapping horizon. Apparent and anti-trapping horizons are timelike surfaces of intermediately singular behavior, which is demonstrated in negative energy density firewalls. These and other properties are also present in axially symmetric solutions. Different generalizations of surface gravity to dynamic spacetimes are discordant and do not match the semiclassical results. We conclude by discussing signatures of these models and implications for the identification of observed ultra-compact objects.

Perceiving Direction in Directionless Time

2021年12月24日 星期五 下午4:02 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Farr, Matt (2021) Perceiving Direction in Directionless Time. [Preprint]

Entropy and Reversible Catalysis

2021年12月23日 星期四 下午6:00 | | | H. Wilming | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): H. Wilming

I show that nondecreasing entropy provides a necessary and sufficient condition to convert the state of a physical system into a different state by a reversible transformation that acts on the system of interest and a further “catalyst,” whose state has to remain invariant exactly in the transition….

[Phys. Rev. Lett. 127, 260402] Published Thu Dec 23, 2021

Riemannian geometry of resonant optical responses

2021年12月23日 星期四 上午8:00 | | | Ashvin Vishwanath | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 23 December 2021; doi:10.1038/s41567-021-01465-z

The modern understanding of quantum transport relies on geometric concepts such as the Berry phase. The geometric approach has now been extended to the theory of optical transitions.

Learning Temporal Quantum Tomography

2021年12月22日 星期三 下午6:00 | | | Quoc Hoan Tran and Kohei Nakajima | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Quoc Hoan Tran and Kohei Nakajima

Quantifying and verifying the control level in preparing a quantum state are central challenges in building quantum devices. The quantum state is characterized from experimental measurements, using a procedure known as tomography, which requires a vast number of resources. However, tomography for a …

[Phys. Rev. Lett. 127, 260401] Published Wed Dec 22, 2021

Quantum Fisher Information from Randomized Measurements

2021年12月22日 星期三 下午6:00 | | | Aniket Rath, Cyril Branciard, Anna Minguzzi, and Benoît Vermersch | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Aniket Rath, Cyril Branciard, Anna Minguzzi, and Benoît Vermersch

The quantum Fisher information (QFI) is a fundamental quantity of interest in many areas from quantum metrology to quantum information theory. It can in particular be used as a witness to establish the degree of multiparticle entanglement in quantum many-body systems. In this work, we use polynomial…

[Phys. Rev. Lett. 127, 260501] Published Wed Dec 22, 2021

A (strictly) contemporary perspective on trans-Planckian censorship

2021年12月20日 星期一 上午9:56 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Schneider, Mike D. (2021) A (strictly) contemporary perspective on trans-Planckian censorship. [Preprint]

2021年12月20日 星期一 上午9:54 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Dumitru, Spiridon (2021) A Survey on Uncertainty Relations and Quantum Measurements: Arguments for Lucrative Parsimony in Approaches of Matters. PROGRESS IN PHYSICS, 17 (1). pp. 38-70. ISSN 1555-5534 (print) 1555-5615 (web)

Wave function realism and three dimensions

2021年12月20日 星期一 上午9:51 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Vaidman, Lev (2021) Wave function realism and three dimensions. [Preprint]

Four Attitudes Towards Singularities in the Search for a Theory of Quantum Gravity

2021年12月19日 星期日 下午7:11 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Crowther, Karen and De Haro, Sebastian (2021) Four Attitudes Towards Singularities in the Search for a Theory of Quantum Gravity. [Preprint]

The constructivist’s programme and the problem of pregeometry

2021年12月19日 星期日 下午7:10 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Linnemann, Niels and Salimkhani, Kian (2021) The constructivist’s programme and the problem of pregeometry. [Preprint]

]]>上午10:36 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Kuby, Daniel (2021) Reinterpreting the universe-multiverse debate in light of inter-model inconsistency in set theory. [Preprint]

On the quantum origin of potentials. (arXiv:2112.08461v1 [quant-ph])

上午10:34 | | | Saurya Das, Sourav Sur | | | quant-ph updates on arXiv.org |

The dynamics of a quantum particle is governed by its wavefunction, which in turn is determined by the classical potential to which it is subjected. However the wavefunction itself induces a quantum potential, the particle `sees’ the sum of the classical and quantum potentials, and there is no way to separate the two. Therefore in principle, part or whole of an observed potential may be attributable to a quantum potential. We examine this possibility and discuss implications.

Axioms for Quantum Gauge Fields. (arXiv:2112.08575v1 [math-ph])

上午10:34 | | | James Glimm, Min Chul Lee | | | quant-ph updates on arXiv.org |

The purpose of this paper is to extend the classical axiom scheme for quantum field theory to include most of the known examples of quantum gauge theories. The axioms are developed in both the Euclidean and Minkowski metrics for space time. We demonstrate that the Euclidean axioms imply the Minkowski (Wightman) axioms. We also prove the reconstruction theorem for Yang-Mills quantum fields as operator-valued tempered distributions with gauge transformation properties.

The universe as a nonlinear quantum simulation. (arXiv:2112.09005v1 [quant-ph])

上午10:34 | | | Michael R. Geller | | | quant-ph updates on arXiv.org |

We investigate a solvable model of nonlinear qubit evolution based on a mapping to an $n$-qubit central spin model in the large $n$ limit, where mean field theory is exact. Extending a theorem of Erd\”os and Schlein to qubits, we establish that the linear central spin model is rigorously dual to a nonlinear qubit. The correspondence explains the origin of qubit torsion, which has been shown by Abrams and Lloyd to enable an exponential speedup for state discrimination in an idealized setting. The duality also suggests that there might not be a sharp distinction between universes evolving according to linear and nonlinear quantum mechanics. In particular, a one-qubit “universe” prepared in a pure state $|\varphi \rangle$ at the time of the big bang and symmetrically coupled to $n$ replicas prepared in the same state, would appear to evolve nonlinearly for any finite time $t>0$ as long as there are exponentially many replicas $n \gg {\rm exp}(O(t))$. Such a universe would appear to support nonlinear quantum evolution.

上午10:34 | | | physics.hist-ph updates on arXiv.org |

Authors: Karen Crowther, Sebastian De Haro

Singularities in general relativity and quantum field theory are often taken not only to motivate the search for a more-fundamental theory (quantum gravity, QG), but also to characterise this new theory and shape expectations of what it is to achieve. Here, we first evaluate how particular types of singularities may suggest an incompleteness of current theories. We then classify four different `attitudes’ towards singularities in the search for QG, and show, through examples in the physics literature, that these lead to different scenarios for the new theory. Two of the attitudes prompt singularity resolution, but only one suggests the need for a theory of QG. Rather than evaluate the different attitudes, we close with some suggestions of factors that influence the choice between them.

Can quantum mechanics breed negative masses?. (arXiv:2112.08881v1 [gr-qc])

上午10:33 | | | gr-qc updates on arXiv.org |

Authors: Bruno Arderucio Costa, George E. A. Matsas

The Casimir effect realizes the existence of static negative energy densities in quantum field theory. We establish physically reasonable conditions for the non-negativity of the total mass of a Casimir apparatus held in equilibrium in the Minkowski background. Specifically, the dynamical equilibrium requires the presence of additional matter to hold the system apart. As long as this extra matter satisfies the dominant energy condition, the mass of the combined system is positive. We discuss the takeaways from the Casimir setting to more general circumstances.

Feyerabend on the quantum theory of measurement: A reassessment

上午4:57 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Kuby, Daniel and Fraser, Patrick (2021) Feyerabend on the quantum theory of measurement: A reassessment. [Preprint]

Infinity and Continuum in the Alternative Set Theory

2021年12月16日 星期四 上午9:32 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Trlifajová, Kateřina (2021) Infinity and Continuum in the Alternative Set Theory. [Preprint]

2021年12月16日 星期四 上午8:00 | | | Nahid Talebi | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 16 December 2021; doi:10.1038/s41567-021-01410-0

Solid-state sources of entangled photons with tailored properties are key elements for integrated quantum computing. Refractive-index perturbations propagating faster than the speed of light may offer a practical approach for generating entangled photon pairs.

Quantum Entanglement from Classical Trajectories

2021年12月15日 星期三 下午6:00 | | | Johan E. Runeson and Jeremy O. Richardson | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Johan E. Runeson and Jeremy O. Richardson

A long-standing challenge in mixed quantum-classical trajectory simulations is the treatment of entanglement between the classical and quantal degrees of freedom. We present a novel approach that describes the emergence of entangled states entirely in terms of independent and deterministic Ehrenfest…

[Phys. Rev. Lett. 127, 250403] Published Wed Dec 15, 2021

Varieties of Humeanism: an introduction

2021年12月13日 星期一 上午8:00 | | | Latest Results for Synthese |

This article does not provide any content.

Comment on `Do electromagnetic waves always propagate along null geodesics?’

2021年12月12日 星期日 下午2:19 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Read, James and Linnemann, Niels (2021) Comment on `Do electromagnetic waves always propagate along null geodesics?’. [Preprint]

Are ‘Particles’ in Quantum Mechanics “Just a Way of Talking”?

2021年12月12日 星期日 下午2:07 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

de Ronde, Christian and Fernández Mouján, Raimundo (2021) Are ‘Particles’ in Quantum Mechanics “Just a Way of Talking”? [Preprint]

]]>上午10:06 | | | Iman Marvian | | | quant-ph updates on arXiv.org |

In the framework of quantum thermodynamics preparing a quantum system in a general state requires the consumption of two distinct resources, namely, work and coherence. It has been shown that the work cost of preparing a quantum state is determined by its free energy. Considering a similar setting, here we determine the coherence cost of preparing a general state when there are no restrictions on work consumption. More precisely, the coherence cost is defined as the minimum rate of consumption of systems in a pure coherent state, that is needed to prepare copies of the desired system. We show that the coherence cost of any system is determined by its quantum Fisher information about the time parameter, hence introducing a new operational interpretation of this central quantity of quantum metrology. Our resource-theoretic approach also reveals a previously unnoticed connection between two fundamental properties of quantum Fisher information.

Bekenstein bound and uncertainty relations. (arXiv:2009.12530v2 [hep-th] UPDATED)

上午10:06 | | | Luca Buoninfante, Giuseppe Gaetano Luciano, Luciano Petruzziello, Fabio Scardigli | | | quant-ph updates on arXiv.org |

The non zero value of Planck constant $h$ underlies the emergence of several inequalities that must be satisfied in the quantum realm, the most prominent one being Heisenberg Uncertainty Principle. Among these inequalities, Bekenstein bound provides a universal limit on the entropy that can be contained in a localized quantum system of given size and total energy. In this Letter, we explore how Bekenstein bound is affected when Heisenberg uncertainty relation is deformed so as to accommodate gravitational effects close to Planck scale (Generalized Uncertainty Principle). By resorting to general thermodynamic arguments, and in regimes where the equipartition theorem still holds, we derive in this way a “generalized Bekenstein bound”. Physical implications of this result are discussed for both cases of positive and negative values of the deformation parameter.

Generalized uncertainty principle or curved momentum space?. (arXiv:2110.11067v3 [gr-qc] UPDATED)

上午10:06 | | | Fabian Wagner | | | quant-ph updates on arXiv.org |

The concept of minimum length, widely accepted as a low-energy effect of quantum gravity, manifests itself in quantum mechanics through generalized uncertainty principles. Curved momentum space, on the other hand, is at the heart of similar applications such as doubly special relativity. We introduce a duality between theories yielding generalized uncertainty principles and quantum mechanics on nontrivial momentum space. In particular, we find canonically conjugate variables which map the former into the latter. In that vein, we explicitly derive the vielbein corresponding to a generic generalized uncertainty principle in $d$ dimensions. Assuming the predominantly used quadratic form of the modification, the curvature tensor in momentum space is proportional to the noncommutativity of the coordinates in the modified Heisenberg algebra. Yet, the metric is non-Euclidean even in the flat case corresponding to commutative space, because the resulting momentum basis is noncanonical. These insides are used to constrain the curvature and the deviation from the canonical basis.

上午10:06 | | | Massimo Blasone, Fabrizio Illuminati, Luciano Petruzziello, Luca Smaldone | | | quant-ph updates on arXiv.org |

We investigate Leggett-Garg temporal inequalities in flavor-mixing processes. We derive an exact flavor-mass uncertainty product and we establish that it is an upper bound to the violation of the inequalities. This finding relates temporal nonclassicality to quantum uncertainty and provides a time analog of the Tsirelson upper bound to the violation of the spatial Bell inequalities. By studying the problem both in the exact field-theoretical setting and in the limiting quantum mechanical approximation, we show that Leggett-Garg inequalities are violated more strongly in quantum field theory than in quantum mechanics.

The origin of irreversibility and thermalization in thermodynamic processes

上午10:06 | | | ScienceDirect Publication: Physics ReportsScienceDirect RSShttps://www.sciencedirect.com/journal/physics-reportsRSS for NodeTue, 23 Jul 2019 10:02:48 GMTCopyright © 2019 Elsevier B.V. All rights reservedRapid solidification as non-ergodic phenomenonPublication date: 20 July 2019Source: Physics Reports, Volume 818Author(s): P.K. Galenko, D. JouAbstractRapid solidification is a relevant physical phenomenon in material sciences, whose theoretical analysis requires going beyond the limits of local equilibrium statistical physics and thermodynamics and, in particular, taking account of ergodicity breaking and of generalized formulation of thermodynamics. The ergodicity breaking is related to the time symmetry breaking and to the presence of some kinds of fluxes and gradient flows making that an average of microscopic variables along time is different than an average over some chosen statistical ensemble. In fast processes, this is due, for instance, to the fact that the system has no time enough to explore the who |

Publication date: 19 January 2022

**Source:** Physics Reports, Volume 944

Author(s): Emil Roduner, Tjaart P.J. Krüger

上午10:06 | | | gr-qc updates on arXiv.org |

Authors: Karthik Rajeev

We consider a proposal to define the wave function of the Universe as a sum over spacetimes that eventually inflate. In the minisuperspace model, we explicitly show that a simple family of initial conditions, parametrized by a positive real number $a_0$, can be imposed to realise this prescription. The resulting wave function is found to be proportional to the Hartle-Hawking wave function and its dependence on $a_0$ is only through an overall phase factor. Motivated by this observation, we ask whether it is possible to analytically extend $a_0$ to an extended region $\bar{\mathcal{D}}$ in complex $a_0-$plane, while retaining the Hartle-Hawking form of the wave function. We use the condition for convergence of path integral and a recent theorem due to Kontsevich and Segal, further extended by Witten, to explicitly find $\bar{\mathcal{D}}$. Interestingly, a special point on the boundary of $\bar{\mathcal{D}}$ recovers the exact no-boundary wave function. Following that, we show that our prescription leads to a family of quantum states for the perturbations, which give rise to scale-invariant power spectra. If we demand, as an extra ingredient to our prescription, a matching condition at the “no-boundary point” in $\bar{\mathcal{D}}$, we converge on a unique quantum state for the perturbations.

Minimal Length Phenomenology and the Black Body Radiation. (arXiv:2112.04609v1 [gr-qc])

上午10:06 | | | gr-qc updates on arXiv.org |

Authors: Pasquale Bosso, Juan Manuel López Vega

The generalized uncertainty principle (GUP) modifies the uncertainty relation between momentum and position giving room for a minimal length, as predicted by candidates theories of quantum gravity. Inspired by GUP, Planck’s distribution is derived by considering a new quantization of the electromagnetic field. We elaborate on the thermodynamics of the black body radiation obtaining Wien’s law and the Stefan-Boltzmann law. We show that such thermodynamics laws are modified at Planck-scale.

Holographic Complexity of Quantum Black Holes. (arXiv:2112.04860v1 [hep-th])

上午10:06 | | | gr-qc updates on arXiv.org |

Authors: Roberto Emparan, Antonia Micol Frassino, Martin Sasieta, Marija Tomašević

We analyze different holographic complexity proposals for black holes that include corrections from bulk quantum fields. The specific setup is the quantum BTZ black hole, which encompasses in an exact manner the effects of conformal fields with large central charge in the presence of the black hole, including the backreaction corrections to the BTZ metric. Our results show that Volume Complexity admits a consistent quantum expansion and correctly reproduces known limits. On the other hand, the generalized Action Complexity fails to account for the additional contributions from bulk quantum fields and does not lead to the correct classical limit. Furthermore, we show that the doubly-holographic setup allows computing the complexity coming purely from quantum fields – a notion that has proven evasive in usual holographic setups. We find that in holographic induced-gravity scenarios the complexity of quantum fields in a black hole background vanishes to leading order in the gravitational strength of CFT effects.

A cautionary case of casual causality. (arXiv:2112.05031v1 [hep-th])

上午10:06 | | | gr-qc updates on arXiv.org |

Authors: Calvin Y.-R. Chen, Claudia de Rham, Aoibheann Margalit, Andrew J. Tolley

We distinguish between the notions of asymptotic causality and infrared causality for gravitational effective field theories, and show that the latter gives constraints consistent with gravitational positivity bounds. We re-explore the scattering of gravitational waves in a spherically symmetric background in the EFT of gravity in $D\ge 5$, for which the leading-order correction to Einstein gravity is determined by the Gauss-Bonnet operator. We reproduce the known result that the truncated effective theory exhibits apparent time advances relative to the background geometry for specific polarisations, which naively signal a violation of causality. We show that by properly identifying the regime of validity of the effective theory, the apparent time advance can be shown to be unresolvable. To illustrate this, we identify specific higher-dimension operators in the EFT expansion which become large for potentially resolvable time advances, rendering the EFT expansion invalid. Our results demonstrate how staying within the confines of the EFT, neither infrared nor asymptotic causality are ever violated for Einstein-Gauss-Bonnet gravity, no matter how low the scale, and furthermore its causality can be understood without appealing to a precise UV completion such as string theory.

上午10:06 | | | gr-qc updates on arXiv.org |

Authors: Camille Bonvin, Felipe Oliveira Franco, Pierre Fleury

The weak equivalence principle is one of the cornerstone of general relativity. Its validity has been tested with impressive precision in the Solar System, with experiments involving baryonic matter and light. However, on cosmological scales and when dark matter is concerned, the validity of this principle is still unknown. In this paper we construct a null test that probes the validity of the equivalence principle for dark matter. Our test has the strong advantage that it can be applied on data without relying on any modelling of the theory of gravity. It involves a combination of redshift-space distortions and relativistic effects in the galaxy number-count fluctuation, that vanishes if and only if the equivalence principle holds. We show that the null test is very insensitive to typical uncertainties in other cosmological parameters, including the magnification bias parameter, and to non-linear effects, making this a robust null test for modified gravity.

The epistemic schism of statistical mechanics

2021年12月9日 星期四 下午6:02 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Anta, Javier (2021) The epistemic schism of statistical mechanics. THEORIA. An International Journal for Theory, History and Foundations of Science, 36 (3). pp. 399-419. ISSN 2171-679X

Conventionalism about time direction

2021年12月9日 星期四 下午6:00 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Farr, Matt (2021) Conventionalism about time direction. [Preprint]

Philosophy, physics, and the problems of spacetime emergence

2021年12月9日 星期四 下午5:59 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Jaksland, Rasmus and Salimkhani, Kian (2021) Philosophy, physics, and the problems of spacetime emergence. [Preprint]

Transforms for the early Kerr metric

2021年12月9日 星期四 下午5:58 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Abbott, Stephen (2021) Transforms for the early Kerr metric. UNSPECIFIED.

2021年12月8日 星期三 下午6:22 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Luc, Joanna (2021) Arguments from scientific practice in the debate about the physical equivalence of symmetry-related models. [Preprint]

The Metaphysics of Emergent Spacetime Theories

2021年12月8日 星期三 下午6:21 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Martens, Niels C.M. (2019) The Metaphysics of Emergent Spacetime Theories. Philosophy Compass, 14 (7).

Introduction to Logical Entropy and Its Relationship to Shannon Entropy

2021年12月8日 星期三 下午6:20 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Ellerman, David (2022) Introduction to Logical Entropy and Its Relationship to Shannon Entropy. [Preprint]

Irreversibility, Loschmidt Echo, and Thermodynamic Uncertainty Relation

2021年12月7日 星期二 下午6:00 | | | Yoshihiko Hasegawa | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Yoshihiko Hasegawa

Entropy production characterizes irreversibility. This viewpoint allows us to consider the thermodynamic uncertainty relation, which states that a higher precision can be achieved at the cost of higher entropy production, as a relation between precision and irreversibility. Considering the original …

[Phys. Rev. Lett. 127, 240602] Published Tue Dec 07, 2021

How to engineer a quantum wavefunction

2021年12月5日 星期日 下午6:05 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Evans, Peter W. and Hangleiter, Dominik and Thebault, Karim P Y (2021) How to engineer a quantum wavefunction. [Preprint]

]]>上午9:53 | | | Benjamin A. Cordier, Nicolas P. D. Sawaya, Gian G. Guerreschi, Shannon K. McWeeney | | | quant-ph updates on arXiv.org |

Quantum computing holds significant potential for applications in biology and medicine, spanning from the simulation of biomolecules to machine learning approaches for subtyping cancers on the basis of clinical features. This potential is encapsulated by the concept of a quantum advantage, which is typically contingent on a reduction in the consumption of a computational resource, such as time, space, or data. Here, we distill the concept of a quantum advantage into a simple framework that we hope will aid researchers in biology and medicine pursuing the development of quantum applications. We then apply this framework to a wide variety of computational problems relevant to these domains in an effort to i) assess the potential of quantum advantages in specific application areas and ii) identify gaps that may be addressed with novel quantum approaches. Bearing in mind the rapid pace of change in the fields of quantum computing and classical algorithms, we aim to provide an extensive survey of applications in biology and medicine that may lead to practical quantum advantages.

上午9:53 | | | James Q. Quach, Timothy C. Ralph, William J. Munro | | | quant-ph updates on arXiv.org |

The Unruh effect can not only arise out of the entanglement between modes of left and right Rindler wedges, but also between modes of future and past light cones. We explore the geometric phase resulting from this timelike entanglement between the future and past, showing that it can be captured in a simple $\Lambda$-system. This provides an alternative paradigm to the Unruh-deWitt detector. The Unruh effect has not been experimentally verified because the accelerations needed to excite a response from Unruh-deWitt detectors are prohibitively large. We demonstrate that a stationary but time-dependent $\Lambda$-system detects the timelike Unruh effect with current technology.

A Quantum Informational Approach to the Problem of Time. (arXiv:2112.00918v1 [gr-qc])

上午9:53 | | | Salman Sajad Wani, James Q. Quach, Mir Faizal, Sebastian Bahamonde, Behnam Pourhassan | | | quant-ph updates on arXiv.org |

Several novel approaches have been proposed to resolve the problem of time by relating it to change. We argue using quantum information theory that the Hamiltonian constraint in quantum gravity cannot probe change, so it cannot be used to obtain a meaningful notion of time. This is due to the absence of quantum Fisher information with respect to the quantum Hamiltonian of a time-reparametization invariant system. We also observe that the inability of this Hamiltonian to probe change can be related to its inability to discriminate between states of such a system. However, if the time-reparametization symmetry is spontaneously broken due to the formation of quantum cosmological time crystals, these problems can be resolved, and it is possible for time to emerge in quantum gravity.

How to engineer a quantum wavefunction. (arXiv:2112.01105v1 [quant-ph])

上午9:53 | | | Peter W. Evans, Dominik Hangleiter amd Karim P. Y. Thébault | | | quant-ph updates on arXiv.org |

In a conventional experiment, inductive inferences between source and target systems are typically justified with reference to a uniformity principle between systems of the same material type. In an analogue quantum simulation, by contrast, scientists aim to learn about target quantum systems of one material type via an experiment on a source quantum system of a different material type. In this paper, we argue that such an inference can be justified by reference to the two quantum systems being of the same empirical type. We illustrate this novel experimental practice of wavefunction engineering with reference to the example of Bose-Hubbard systems.

上午9:53 | | | Donghoon Ha, Jeong San Kim | | | quant-ph updates on arXiv.org |

The phenomenon of nonlocality without entanglement(NLWE) arises in discriminating multi-party quantum separable states. Recently, it has been found that the post-measurement information about the prepared subensemble can lock or unlock NLWE in minimum-error discrimination of non-orthogonal separable states. Thus It is natrual to ask whether the availability of the post-measurement information can influence on the occurrence of NLWE even in other state-discrimination stratigies. Here, we show that the post-measurement information can be used to lock as well as unlock the occurence of NLWE in terms of optimal nambiguous discrimination. Our results can provide a useful application for hiding or sharing information based on non-orthogonal separable states.

上午9:53 | | | Walter F. Wreszinski | | | quant-ph updates on arXiv.org |

The second law of thermodynamics, viewed as a theorem asserting the growth of the mean (Gibbs-von Neumann) entropy of a class of quantum spin systems undergoing automorphic (unitary) adiabatic transformations, is proved. Non-automorphic interactions with the environment, although known to produce on the average a strict reduction of the entropy of systems with finite number of degrees of freedom, are proved to conserve the mean entropy on the average, for some models of quantum spin systems. Some related results on the approach (or return) to equilibrium are also reviewed. The results depend crucially on two properties of the mean entropy, proved by Robinson and Ruelle for classical systems, and Lanford and Robinson for quantum lattice systems: upper semicontinuity and affinity.

上午9:53 | | | James Sud, Victor Li | | | quant-ph updates on arXiv.org |

Disruptions of university campuses caused by COVID-19 have motivated strategies to prevent the spread of infectious diseases while maintaining some level of in person learning. In response, the proposed approach recursively applied a quantum annealing algorithm for Max-Cut optimization on D-Wave Systems, which grouped students into cohorts such that the number of possible infection events via shared classrooms was minimized. To test this approach, available coursework data was used to generate highly clustered course enrollment networks representing students and the classes they share. The algorithm was then recursively called on these networks to group students, and a disease model was applied to forecast disease spread. Simulation results showed that under some assumptions on disease statistics and methods of spread, the quantum grouping method reduced both the total and peak percentage of infected students when compared against random groupings of students. Scaling to larger networks, it is possible that this quantum annealer-assisted grouping approach may provide practical advantage over classical approaches. This paper, however, is strictly a proof-of-concept demonstration of the approach and is not intended to argue for a quantum speedup.

上午9:53 | | | Vahid Salari, Serafim Rodrigues, Erhan Saglamyurek, Christoph Simon, Daniel Oblak | | | quant-ph updates on arXiv.org |

The present paper examines the viability of a radically novel idea for brain-computer interface (BCI), which could lead to novel technological, experimental and clinical applications. BCIs are computer-based systems that enable either one-way or two-way communication between a living brain and an external machine. BCIs read-out brain signals and transduce them into task commands, which are performed by a machine. In closed-loop, the machine can stimulate the brain with appropriate signals. In recent years, it has been shown that there is some ultraweak light emission from neurons within or close to the visible and near-infrared parts of the optical spectrum. Such ultraweak photon emission (UPE) reflects the cellular (and body) oxidative status, and compelling pieces of evidence are beginning to emerge that UPE may well play an informational role in neuronal functions. In fact, several experiments point to a direct correlation between UPE intensity and neural activity, oxidative reactions, EEG activity, cerebral blood flow, cerebral energy metabolism, and release of glutamate. Here, we propose a novel skull implant BCI that uses UPE. We suggest that a photonic integrated chip installed on the interior surface of the skull may enable a new form of extraction of the relevant features from the UPE signals. In the current technology landscape, photonic technologies advance rapidly and poised to overtake many electrical technologies, due to their unique advantages, such as miniaturization, high speed, low thermal effects, and large integration capacity that allow for high yield, volume manufacturing, and lower cost. For our proposed BCI, we make some major conjectures, which need to be experimentally verified, and hence we discuss the controversial parts, feasibility of technology and limitations, and potential impact of this envisaged technology if successfully implemented in the future.

Emergent universe revisited through the CSL theory. (arXiv:2108.01472v2 [gr-qc] UPDATED)

上午9:53 | | | Gabriel R. Bengochea, María Pía Piccirilli, Gabriel León | | | quant-ph updates on arXiv.org |

In this work we analyze how the spectrum of primordial scalar perturbations is modified, within the emergent universe scenario, when a particular version of the Continuous Spontaneous Localization (CSL) model is incorporated as the generating mechanism of initial perturbations, providing also an explanation to the quantum-to-classical transition of such perturbations. On the other hand, a phase of super-inflation, prior to slow-roll inflation, is a characteristic feature of the emergent universe hypothesis. In recent works, it was shown that the super-inflation phase could generically induce a suppression of the temperature anisotropies of the CMB at large angular scales. We study here under what conditions the CSL maintains or modifies these characteristics of the emergent universe and their compatibility with the CMB observations.

Detectable Gravitational Wave Signals from Inflationary Preheating. (arXiv:2112.00762v1 [hep-ph])

上午9:53 | | | gr-qc updates on arXiv.org |

Authors: Yanou Cui, Evangelos I. Sfakianakis

We consider gravitational wave (GW) production during preheating in hybrid inflation models where an axion-like waterfall field couples to Abelian gauge fields. Based on a linear analysis, we find that the GW signal from such models can be within the reach of a variety of foreseeable GW experiments such as LISA, AEDGE, ET and CE, and is close to that of LIGO A+, both in terms of frequency range and signal strength. Furthermore, the resultant GW signal is helically polarized and thus may distinguish itself from other sources of stochastic GW background. Finally, such models can produce primordial black holes that can compose dark matter and lead to merger events detectable by GW detectors.

Generalised proofs of the first law of entanglement entropy. (arXiv:2112.00972v1 [hep-th])

上午9:53 | | | gr-qc updates on arXiv.org |

Authors: Marika Taylor, Linus Too

In this paper we develop generalised proofs of the holographic first law of entanglement entropy using holographic renormalisation. These proofs establish the holographic first law for non-normalizable variations of the bulk metric, hence relaxing the boundary conditions imposed on variations in earlier works. Boundary and counterterm contributions to conserved charges computed via covariant phase space analysis have been explored previously. Here we discuss in detail how counterterm contributions are treated in the covariant phase approach to proving the first law. Our methodology would be applicable to generalizing other holographic information analyses to wider classes of gravitational backgrounds.

Stochastic Quantization of General Relativity \`a la Ricci-Flow. (arXiv:2112.01490v1 [gr-qc])

上午9:53 | | | gr-qc updates on arXiv.org |

Authors: Matteo Lulli, Antonino Marciano, Xiaowen Shan

We follow a new pathway to the definition of the Stochastic Quantization (SQ), first proposed by Parisi and Wu, of the action functional yielding the Einstein equations. Hinging on the functional similarities between the Ricci-Flow equation and the SQ Langevin equations, we push forward a novel approach in which the stochastic time converges to the proper time of a space-like foliation in the equilibrium limit. This procedure in turn requires adding to the usual symmetric connection a projective Weyl term that does not modify the classical equations of motion. Furthermore, we express the starting system of equations using the Arnowitt-Deser-Misner (ADM) variables and their conjugated Hamiltonian momenta. Such a choice is instrumental for understanding the newly derived equations in terms of the breaking the diffeomorphism invariance of the classical theory, which will hold on average at the steady state. We comment on the physical interpretation of the Ricci flow equations, and argue how they can naturally provide, in a geometrical way, the renormalization group equation for gravity theories. In the general setting, the equation associated to the shift vector yields the Navier-Stokes equation with a stochastic source. Moreover, we show that the fluctuations of the metric tensor components around the equilibrium configurations, far away from the horizon of a Schwarzschild black hole, are forced by the Ricci flow to follow the Kardar-Parisi-Zhang equation, whose probabilistic distribution can yield an intermittent statistics. We finally comment on the possible applications of this novel scenario to the cosmological constant, arguing that the Ricci flow may provide a solution to the Hubble tension, as a macroscopic effect of the quantum fluctuation of the metric tensor.

2021年12月2日 星期四 下午6:31 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Suárez, Mauricio (2016) The Chances of Propensities. [Preprint]

What is So Special about Analogue Simulations?

2021年12月2日 星期四 下午6:30 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Nappo, Francesco (2021) What is So Special about Analogue Simulations? [Preprint]

Quantum and Classical Temporal Correlations in $(1+1)\mathrm{D}$ Quantum Cellular Automata

2021年12月1日 星期三 下午6:00 | | | Edward Gillman, Federico Carollo, and Igor Lesanovsky | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Edward Gillman, Federico Carollo, and Igor Lesanovsky

We employ (1+1)-dimensional quantum cellular automata to study the evolution of entanglement and coherence near criticality in quantum systems that display nonequilibrium steady-state phase transitions. This construction permits direct access to the entire space-time structure of the underlying none…

[Phys. Rev. Lett. 127, 230502] Published Wed Dec 01, 2021

Against the disappearance of spacetime in quantum gravity

2021年12月1日 星期三 上午8:00 | | | Latest Results for Synthese |

**Abstract**

This paper argues against the proposal to draw from current research into a physical theory of quantum gravity the ontological conclusion that spacetime or spatiotemporal relations are not fundamental. As things stand, the status of this proposal is like the one of all the other claims about radical changes in ontology that were made during the development of quantum mechanics and quantum field theory. However, none of these claims held up to scrutiny as a consequence of the physics once the theory was established and a serious discussion about its ontology had begun. Furthermore, the paper argues that if spacetime is to be recovered through a functionalist procedure in a theory that admits no fundamental spacetime, standard functionalism cannot serve as a model: all the known functional definitions are definitions in terms of a causal role for the motion of physical objects and hence presuppose spatiotemporal relations.

Spatial experience, spatial reality, and two paths to primitivism

2021年12月1日 星期三 上午8:00 | | | Latest Results for Synthese |

**Abstract**

I explore two views about the relationship between spatial experience and spatial reality: *spatial functionalism* and *spatial presentationalism*. Roughly, spatial functionalism claims that the instantiated spatial properties are those playing a certain causal role in producing spatial experience while spatial presentationalism claims that the instantiated spatial properties include those presented in spatial experience. I argue that each view, in its own way, leads to an ontologically inflationary form of primitivism: whereas spatial functionalism leads to primitivism about phenomenal representation, spatial presentationalism leads to primitivism about spatial properties. I conclude by discussing how to adjudicate between spatial functionalism and spatial presentationalism.

2021年12月1日 星期三 上午7:21 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Chua, Eugene Y. S. (2021) Degeneration and Entropy. [Preprint]

2021年11月30日 星期二 上午8:00 | | | Young-Woo Son | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 30 November 2021; doi:10.1038/s41567-021-01457-z

Charge density waves are the periodic spatial modulation of electrons in a solid. A new experiment reveals that they can originate from two different electronic bands in a prototypical transition metal dichalcogenide, NbSe2.

Is the photon really a particle?

2021年11月29日 星期一 上午8:31 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Klevgard, Paul A. (2021) Is the photon really a particle? Optik International Journal for Light and Electron Optics, 237 (166679). ISSN 0030-4026

Forced Changes Only: A New Take on the Law of Inertia

2021年11月28日 星期日 下午6:35 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hoek, Daniel (2021) Forced Changes Only: A New Take on the Law of Inertia. [Preprint]

The physics and metaphysics of Tychistic Bohmian Mechanics

2021年11月28日 星期日 下午6:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Duerr, Patrick and Ehmann, Alexander (2021) The physics and metaphysics of Tychistic Bohmian Mechanics. Studies in History and Philosophy of Science Part A, 90. pp. 168-183. ISSN 00393681

Are ‘Particles’ in Quantum Mechanics “Just a Way of Talking”?

2021年11月28日 星期日 下午6:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

de Ronde, Christian and Fernández Mouján, Raimundo (2021) Are ‘Particles’ in Quantum Mechanics “Just a Way of Talking”? [Preprint]

Could Charge and Mass be Universals?

2021年11月26日 星期五 上午10:52 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Gilton, Marian (2020) Could Charge and Mass be Universals? [Preprint]

2021年11月26日 星期五 上午10:49 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Tabatabaei Ghomi, Hamed (2021) Setting the demons loose: computational irreducibility does not guarantee unpredictability or emergence. [Preprint]

]]>2021年11月15日 星期一 下午6:18 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Healey, Richard (2021) Beyond Bell? [Preprint]

Quantum technologies need a quantum energy initiative. (arXiv:2111.09241v2 [quant-ph] UPDATED)

上午9:19 | | | A. Auffèves | | | quant-ph updates on arXiv.org |

Quantum technologies are currently the object of high expectations from governments and private companies, as they hold the promise to shape safer and faster ways to exchange and treat information. However, despite its major potential impact for industry and society, the question of their energetic footprint has remained in a blind spot of current deployment strategies. In this Perspective, I argue that quantum technologies must urgently plan for the creation and structuration of a transverse quantum energy initiative, connecting quantum thermodynamicists, computer scientists, experimenters and engineers. Such initiative is the only path towards sustainable quantum technologies, help reducing the cost of classical information processing, and possibly bring out an energetic quantum advantage.

The Quantum Eraser Paradox. (arXiv:2111.09347v1 [quant-ph])

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

Authors: Colm Bracken, Jonte R. Hance, Sabine Hossenfelder

The Delayed-Choice Quantum Eraser experiment is commonly interpreted as implying that in quantum mechanics a choice made at one time can influence an earlier event. We here suggest an extension of the experiment that results in a paradox when interpreted using a local realist interpretation combined with backward causation (“retrocausality”). We argue that resolving the paradox requires giving up the idea that, in quantum mechanics, a choice can influence the past, and that it instead requires a violation of Statistical Independence without retrocausality. We speculate what the outcome of the experiment would be.

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

Authors: Andrew J. S. Hamilton

This paper presents a pedagogical introduction to the issue of how to implement Lorentz transformations in relativistic visualization. The most efficient approach is to use the even geometric algebra in 3+1 spacetime dimensions, or equivalently complex quaternions, which are fast, compact, and robust, and straightforward to compose, interpolate, and spline. The approach has been incorporated into the Black Hole Flight Simulator, an interactive general relativistic ray-tracing program developed by the author.

Embedding Causal Sets into Minkowski Spacetime. (arXiv:2111.09331v1 [gr-qc])

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

Authors: Steven Johnston

We present a new method for embedding a causal set into an interval of Minkowski spacetime. The method uses spacetime volumes for causally related elements to define causal set analogs of Minkowski inner products. These are used to construct matrices of inner products which are then factored using the singular value decomposition to give coordinates in Minkowski spacetime. Results are presented showing good quality embeddings into Minkowski spacetime for dimensions d=2,3,4. The method applies in any dimension and does not require spacelike distances to be used as an input. It offers a new way to define spatial orientation and spacelike distances in a causal set.

Islands in Multiverse Models. (arXiv:2108.01278v2 [hep-th] UPDATED)

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

Authors: Sergio E. Aguilar-Gutierrez, Aidan Chatwin-Davies, Thomas Hertog, Natalia Pinzani-Fokeeva, Brandon Robinson

We consider multiverse models in two-dimensional linear dilaton-gravity theories as toy models of false vacuum eternal inflation. Coupling conformal matter we calculate the Von Neumann entropy of subregions. When these are sufficiently large we find that an island develops covering most of the rest of the multiverse, leading to a Page-like transition. This resonates with a description of multiverse models in semiclassical quantum cosmology, where a measure for local predictions is given by saddle point geometries which coarse-grain over any structure associated with eternal inflation beyond one’s patch.

2021年11月19日 星期五 下午5:55 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Merritt, David (2021) MOND and Methodology. Karl Popper’s Science and Philosophy. pp. 69-96.

Autonomy generalised; or, Why doesn’t physics matter more?

2021年11月19日 星期五 下午5:54 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Robertson, Katie (2021) Autonomy generalised; or, Why doesn’t physics matter more? [Preprint]

What’s so special about initial conditions? Understanding the past hypothesis in directionless time

2021年11月19日 星期五 下午5:50 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Farr, Matt (2021) What’s so special about initial conditions? Understanding the past hypothesis in directionless time. [Preprint]

The physics and metaphysics of Tychistic Bohmian Mechanics

2021年11月15日 星期一 下午6:20 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Duerr, Patrick and Ehmann, Alexander (2021) The physics and metaphysics of Tychistic Bohmian Mechanics. Stuidies in History and Philosophy of Science Part A, 90. pp. 168-183.

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