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

Authors: William Graham Hoover, Carol Griswold Hoover

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

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

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

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

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

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

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

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

Authors: David Sloan

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

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

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

Authors: Sinya Aoki, Tetsuya Onogi, Shuichi Yokoyama

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

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

Authors: Patrick Das Gupta

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

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

Authors: Matsuo Sato, Yuji Sugimoto

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

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

Authors: Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto

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

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

2020年10月16日 星期五 下午8:08 | | | ScienceDirect Publication: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsScienceDirect RSShttps://www.sciencedirect.com/journal/studies-in-history-and-philosophy-of-science-part-b-studies-in-history-and-philosophy-of-modern-physicsRSS for NodeWed, 24 Jul 2019 09:46:42 GMTCopyright © 2019 Elsevier Ltd. All rights reservedImprints of the underlying structure of physical theoriesPublication date: Available online 12 July 2019Source: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsAuthor(s): Jorge ManeroAbstractIn the context of scientific realism, this paper intends to provide a formal and accurate description of the structural-based ontology posited by classical mechanics, quantum mechanics and special relativity, which is preserved across the empirical domains of these theories and explain their successful predictions. Along the lines of ontic structural realism, such a description is undertaken by |

Publication date: Available online 16 October 2020

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

Author(s): Paul M. Näger

Setting Up Experimental Bell Tests with Reinforcement Learning

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

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

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

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

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

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

There is no new problem for quantum mechanics

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

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

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

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

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

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

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

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

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

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

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

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

C-theories of time: On the adirectionality of time

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

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

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

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

A Synopsis of the Minimal Modal Interpretation of Quantum Theory

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

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

The Minimal Modal Interpretation of Quantum Theory

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

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

Uncomputable but complete physics theory of the universe

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

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

Can the universe be in a mixed state?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Authors: Michael J.W. Hall

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

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

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

Authors: Behnam Pourhassan

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

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

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

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

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

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

Authors: Vladimir V. Kassandrov, Nina V. Markova

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

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

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

Authors: John R. Klauder

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

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

Authors: Jerome Martin, Vincent Vennin

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

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

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

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

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

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

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

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

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

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

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

Intercontinental comparison of optical atomic clocks through very long baseline interferometry

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

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

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

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

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

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

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

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

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

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

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

A New Perspective On Time And Physical Laws

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

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

Quantum probability’s algebraic origin

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

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

Learning Entropy Production via Neural Networks

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Authors: G.J. Ehnholm, M. Krusius

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

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

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

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

The dynamical approach to spin-2 gravity

2020年10月2日 星期五 上午10:04 | | | ScienceDirect Publication: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsScienceDirect RSShttps://www.sciencedirect.com/journal/studies-in-history-and-philosophy-of-science-part-b-studies-in-history-and-philosophy-of-modern-physicsRSS for NodeWed, 24 Jul 2019 09:46:42 GMTCopyright © 2019 Elsevier Ltd. All rights reservedImprints of the underlying structure of physical theoriesPublication date: Available online 12 July 2019Source: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsAuthor(s): Jorge ManeroAbstractIn the context of scientific realism, this paper intends to provide a formal and accurate description of the structural-based ontology posited by classical mechanics, quantum mechanics and special relativity, which is preserved across the empirical domains of these theories and explain their successful predictions. Along the lines of ontic structural realism, such a description is undertaken by |

Publication date: Available online 28 September 2020

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

Author(s): Kian Salimkhani

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

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

Authors: Lavinia Heisenberg, Hector Villarrubia-Rojo

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

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

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

Authors: O. B. Zaslavskii

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

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

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

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

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

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

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

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

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

Mind the gap

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

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

Ising model for strings

INFORMATION-DEVOID ROUTES FOR SCALE-FREE NEURODYNAMICS

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

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

What does the world look like according to superdeterminism?

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

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

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

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

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

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

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

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

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

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

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

Gauge Invariance for Classical Massless Particles with Spin

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

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

]]>A hidden variables matrix mechanics model of the harmonic oscillator is presented as a counter-example in examining fundamental assumptions of quantum mechanics. Solutions are obtained which can be interpreted as describing continuous motion of a particle at all times located at points in space. While this is contrary to the basic postulate of Heisenberg, the experimental results of the standard matrix mechanics treatment are nevertheless reproduced. The proposed model is motivated by the foundational issues raised by Bell. Inequalities violation is however, attributed to the mathematical representation of outcome quantities as metric variables rather than the consensus assumption of local causality. Examining the consequence of this alternative conclusion on an actual quantum system creates an overlapping between Bell inspired foundational issues and the original postulates of Heisenberg and Born. Heisenberg’s basic postulates – randomness of transitions and treating the system as an ensemble – are critical. Bohr’s assumption that transitions occur instantaneously, together with Heisenberg’s non-path postulate where the particle can be measured at spatially separated locations without continuous movement between locations, are discarded. Heisenberg’s measurable-only quantities are interpreted as arising from a substructure of periodic endogenous motion of the system.

]]>上午9:49 | | | P. Navez, A. G. Balanov, S. E. Savel’ev, A. M. Zagoskin | | | quant-ph updates on arXiv.org |

Using an analytically solvable model, we show that a qubit array-based detector allows to achieve the fundamental Heisenberg limit in detecting single photons. In case of superconducting qubits, this opens new opportunities for quantum sensing and communications in the important microwave range.

Post-Newtonian Description of Quantum Systems in Gravitational Fields. (arXiv:2009.11319v1 [gr-qc])

上午9:49 | | | physics.hist-ph updates on arXiv.org |

Authors: Philip K. Schwartz

This thesis deals with the systematic treatment of quantum-mechanical systems in post-Newtonian gravitational fields. Starting from clearly spelled-out assumptions, employing a framework of geometric background structures defining the notion of a post-Newtonian expansion, our systematic approach allows to properly derive the post-Newtonian coupling of quantum-mechanical systems to gravity based on first principles. This sets it apart from more heuristic approaches that are commonly employed, for example, in the description of quantum-optical experiments under gravity.

Regarding single particles, we compare simple canonical quantisation of a free particle in curved spacetime to formal expansions of the minimally coupled Klein-Gordon equation, which may be motivated from QFT in curved spacetimes. Specifically, we develop a general WKB-like post-Newtonian expansion of the KG equation to arbitrary order in $c^{-1}$. Furthermore, for stationary spacetimes, we show that the Hamiltonians arising from expansions of the KG equation and from canonical quantisation agree up to linear order in particle momentum, independent of any expansion in $c^{-1}$.

Concerning composite systems, we perform a fully detailed systematic derivation of the first order post-Newtonian quantum Hamiltonian describing the dynamics of an electromagnetically bound two-particle system situated in external electromagnetic and gravitational fields, the latter being described by the Eddington-Robertson PPN metric.

In the last, independent part of the thesis, we prove two uniqueness results characterising the Newton–Wigner position observable for Poincar\’e-invariant classical Hamiltonian systems: one is a direct classical analogue of the quantum Newton–Wigner theorem, and the other clarifies the geometric interpretation of the Newton–Wigner position as `centre of spin’, as proposed by Fleming in 1965.

上午9:49 | | | physics.hist-ph updates on arXiv.org |

Authors: Luca Callegaro, Francesca Pennecchi, Walter Bich

The paper “Physics without determinism: Alternative interpretations of classical physics” [Phys. Rev. A, 100:062107, Dec 2019] defines finite information quantities (FIQ). A FIQ expresses the available information about the value of a physical quantity. We show that a change in the measurement unit does not preserve the information carried by a FIQ, and therefore that the definition provided in the paper is not complete.

Time Travel Paradoxes and Multiple Histories. (arXiv:1911.11590v2 [gr-qc] UPDATED)

上午9:49 | | | physics.hist-ph updates on arXiv.org |

Authors: Jacob Hauser, Barak Shoshany

If time travel is possible, it seems to inevitably lead to paradoxes. These include consistency paradoxes, such as the famous grandfather paradox, and bootstrap paradoxes, where something is created out of nothing. One proposed class of resolutions to these paradoxes allows for multiple histories (or timelines), such that any changes to the past occur in a new history, independent of the one where the time traveler originated. We introduce a simple mathematical model for a spacetime with a time machine, and suggest two possible multiple-histories models, making use of branching spacetimes and covering spaces respectively. We use these models to construct novel and concrete examples of multiple-histories resolutions to time travel paradoxes, and we explore questions such as whether one can ever come back to a previously visited history and whether a finite or infinite number of histories is required. Interestingly, we find that the histories may be finite and cyclic under certain assumptions, in a way which extends the Novikov self-consistency conjecture to multiple histories and exhibits hybrid behavior combining the two. Investigating these cyclic histories, we rigorously determine how many histories are needed to fully resolve time travel paradoxes for particular laws of physics. Finally, we discuss how observers may experimentally distinguish between multiple histories and the Hawking and Novikov conjectures.

Kant and Hegel in Physics. (arXiv:2009.06198v2 [physics.hist-ph] UPDATED)

上午9:49 | | | physics.hist-ph updates on arXiv.org |

Authors: Y.S.Kim

Kant and Hegel are among the philosophers who are guiding the way in which we reason these days. It is thus of interest to see how physical theories have been developed along the line of Kant and Hegel. Einstein became interested in how things appear to moving observers. Quantum mechanics is also an observer-dependent science. The question then is whether quantum mechanics and relativity can be synthesized into one science. The present form of quantum field theory is a case in point. This theory however is based on the algorithm of the scattering matrix where all participating particles are free in the remote past and in the remote future. We thus need, in addition, a Lorentz-covariant theory of bound state which will address the question of how the hydrogen atom would look to moving observers. The question is then whether this Lorentz-covariant theory of bound states can be synthesized with the field theory into a Lorentz-covariant quantum mechanics. This article reviews the progress made along this line. This integrated Kant-Hegel process is illustrated in terms of the way in which Americans practice their democracy.

On Quantum Simulation Of Cosmic Inflation. (arXiv:2009.10921v2 [quant-ph] UPDATED)

上午9:49 | | | gr-qc updates on arXiv.org |

Authors: Yue-Zhou Li, Junyu Liu

In this paper, we generalize Jordan-Lee-Preskill, an algorithm for simulating flat-space quantum field theories, to 3+1 dimensional inflationary spacetime. The generalized algorithm contains the encoding treatment, the initial state preparation, the inflation process, and the quantum measurement of cosmological observables at late time. The algorithm is helpful for obtaining predictions of cosmic non-Gaussianities, serving as useful benchmark problems for quantum devices, and checking assumptions made about interacting vacuum in the inflationary perturbation theory.

Components of our work also include a detailed discussion about the lattice regularization of the cosmic perturbation theory, a detailed discussion about the in-in formalism, a discussion about encoding using the HKLL-type formula that might apply for both dS and AdS spacetimes, a discussion about bounding curvature perturbations, a description of the three-party Trotter simulation algorithm for time-dependent Hamiltonians, a ground state projection algorithm for simulating gapless theories, a discussion about the quantum-extended Church-Turing Thesis, and a discussion about simulating cosmic reheating in quantum devices.

Definitions more geometrarum and Newton’s scholium on space and time

上午9:49 | | | ScienceDirect Publication: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsScienceDirect RSShttps://www.sciencedirect.com/journal/studies-in-history-and-philosophy-of-science-part-b-studies-in-history-and-philosophy-of-modern-physicsRSS for NodeWed, 24 Jul 2019 09:46:42 GMTCopyright © 2019 Elsevier Ltd. All rights reservedImprints of the underlying structure of physical theoriesPublication date: Available online 12 July 2019Source: Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern PhysicsAuthor(s): Jorge ManeroAbstractIn the context of scientific realism, this paper intends to provide a formal and accurate description of the structural-based ontology posited by classical mechanics, quantum mechanics and special relativity, which is preserved across the empirical domains of these theories and explain their successful predictions. Along the lines of ontic structural realism, such a description is undertaken by |

Publication date: Available online 24 September 2020

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

Author(s): Zvi Biener

A sideways look at faithfulness for quantum correlations

上午1:04 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Evans, Peter W. (2020) A sideways look at faithfulness for quantum correlations. [Preprint]

Trans-Planckian Philosophy of Cosmology

2020年9月25日 星期五 上午11:26 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Schneider, Mike D. (2020) Trans-Planckian Philosophy of Cosmology. [Preprint]

Debunking prevailing explanations for the emergence of classicality in cosmology

2020年9月25日 星期五 上午11:25 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Berjon, Javier and Okon, Elias and Sudarsky, Daniel (2020) Debunking prevailing explanations for the emergence of classicality in cosmology. [Preprint]

Conformal invariance of the Newtonian Weyl tensor

2020年9月22日 星期二 上午10:57 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Dewar, Neil and Read, James (2020) Conformal invariance of the Newtonian Weyl tensor. [Preprint]

What Price Changing Laws of Nature?

2020年9月22日 星期二 上午10:56 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Sartenaer, Olivier and Guay, Alexandre and Humphreys, Paul (2020) What Price Changing Laws of Nature? [Preprint]

Time–information uncertainty relations in thermodynamics

2020年9月21日 星期一 上午8:00 | | | Jason R. Green | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 21 September 2020; doi:10.1038/s41567-020-0981-y

A time–information uncertainty relation in thermodynamics has been derived, analogous to the time–energy uncertainty relation in quantum mechanics, imposing limits on the speed of energy and entropy exchange between a system and external reservoirs.

Machine learning the thermodynamic arrow of time

2020年9月21日 星期一 上午8:00 | | | Christopher Jarzynski | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 21 September 2020; doi:10.1038/s41567-020-1018-2

The phrase ‘arrow of time’ refers to the asymmetry in the flow of events. A machine learning algorithm trained to infer its direction identifies entropy production as the relevant underlying physical principle in the decision-making process.

Observation of energy-resolved many-body localization

2020年9月21日 星期一 上午8:00 | | | H. Wang | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 21 September 2020; doi:10.1038/s41567-020-1035-1

Many-body localization—a phenomenon where an isolated system fails to reach thermal equilibrium—has been studied with a programmable quantum processor, which reveals the crucial role played by the initial energy on the onset of localization.

A different approach to logic: absolute logic

2020年9月20日 星期日 上午7:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Avon, Mauro (2020) A different approach to logic: absolute logic. [Preprint]

The Past Hypothesis and the Nature of Physical Laws

2020年9月19日 星期六 下午11:11 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Chen, Eddy Keming (2020) The Past Hypothesis and the Nature of Physical Laws. [Preprint]

2020年9月19日 星期六 下午11:09 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Weatherall, James Owen (2020) Two Dogmas of Dynamicism. [Preprint]

]]>上午8:00 | | | Latest Results for Synthese |

**Abstract**

Realists wanting to capture the facts of quantum entanglement in a metaphysical interpretation find themselves faced with several options: to grant some species of fundamental nonseparability, adopt holism, or (more radically) to view localized spacetime systems as ultimately reducible to a higher-dimensional entity, the quantum state or wave function. Those adopting the latter approach and hoping to view the macroscopic world as grounded in the quantum wave function face the macro-object problem. The challenge is to articulate the metaphysical relation obtaining between three-dimensional macro-objects and the wave function so that the latter may be seen in some sense as constituting the former. This paper distinguishes several strategies for doing so and defends one based on a notion of partial instantiation.

Mechanisms for constrained stochasticity

上午8:00 | | | Latest Results for Synthese |

**Abstract**

Creativity is generally thought to be the production of things that are *novel* and *valuable* (whether physical artefacts, actions, or ideas). Humans are unique in the extent of their creativity, which plays a central role in innovation and problem solving, as well as in the arts. But what are the cognitive sources of novelty? More particularly, what are the cognitive sources of stochasticity in creative production? I will argue that they belong to two broad categories. One is associative, enabling the selection of goal-relevant ideas that have become activated by happenstance in an unrelated context. The other relies on selection processes that leverage stochastic fluctuations in neural activity. At the same time, I will address a central puzzle, which is to understand how the outputs of stochastic processes can nevertheless generally fall within task constraints. While the components appealed to in the accounts that I offer are well established, the ways in which I combine them together are new.

上午8:00 | | | Latest Results for Synthese |

**Abstract**

A simple argument proposes a direct link between realism about quantum mechanics and one kind of metaphysical holism: if elementary quantum theory is at least approximately true, then there are entangled systems with intrinsic whole states for which the intrinsic properties and spatiotemporal arrangements of salient subsystem parts do not suffice. Initially, the proposal is compelling: we can find variations on such reasoning throughout influential discussions of entanglement. Upon further consideration, though, this simple argument proves a bit too simple. To get such metaphysically robust consequences out, we need to put more than minimal realism in. This paper offers a diagnosis: our simple argument seems so compelling thanks to an equivocation. The predictions of textbook quantum theory already resonate with familiar holistic slogans; for realists, then, any underlying reality, conforming to such predictions, also counts as holistic in some sense or other, if only by association. Such associated holism, though, does not establish the sort of specific, robust supervenience failure claimed by our simple argument. While it may be natural to slide to this stronger conclusion, facilitating the slide is not minimal realism per se but an additional explanatory assumption about how and why reality behaves in accordance with our theory: roughly, quantum theory accurately captures patterns in the features and behaviors of physical reality *because* some underlying metaphysical structure constrains reality to exhibit these patterns. Along with the diagnosis comes a recommendation: we can and should understand one traditional disagreement about the metaphysics of entanglement as another manifestation of a familiar and more general conflict between reductive and non-reductive conceptions of metaphysical theorizing. Such reframing makes clearer what resources reductionists have for resisting the simple argument’s challenge from quantum holism. It also has an important moral for their opponents. Traditional focus on whole-part supervenience failure distracts from a root disagreement about metaphysical structure and its role in our theorizing. Non-reductionists fond of our simple argument would be better off tackling this root directly.

上午8:00 | | | Latest Results for Synthese |

**Abstract**

This paper critically assesses whether quantum entanglement can be made compatible with Humean supervenience. After reviewing the prima facie tension between entanglement and Humeanism, I outline a recently-proposed Humean response, and argue that it is subject to two problems: one concerning the determinacy of quantities, and one concerning its relationship to scientific practice.

Quantum holism: nonseparability as common ground

上午8:00 | | | Latest Results for Synthese |

**Abstract**

Quantum mechanics seems to portray nature as nonseparable, in the sense that it allows spatiotemporally separated entities to have states that cannot be fully specified without reference to each other. This is often said to implicate some form of “holism.” We aim to clarify what this means, and why this seems plausible. Our core idea is that the best explanation for nonseparability is a “common ground” explanation (modeled after common cause explanations), which casts nonseparable entities in a holistic light, as scattered reflections of a more unified underlying reality.

Quantum metaphysical indeterminacy and worldly incompleteness

上午8:00 | | | Latest Results for Synthese |

**Abstract**

An influential theory has it that metaphysical indeterminacy occurs just when reality can be made completely precise in multiple ways. That characterization is formulated by employing the modal apparatus of ersatz possible worlds. As quantum physics taught us, reality cannot be made completely precise. I meet the challenge by providing an alternative theory which preserves the use of ersatz worlds but rejects the precisificational view of metaphysical indeterminacy. The upshot of the proposed theory is that it is metaphysically indeterminate whether *p* just in case it is neither true nor false that *p*, and no terms in ‘*p*’ are semantically defective. In other words, metaphysical indeterminacy arises when the world cannot be adequately described by a complete set of sentences defined in a semantically nondefective language. Moreover, the present theory provides a reductive analysis of metaphysical indeterminacy, unlike its influential predecessor. Finally, I argue that any adequate logic of a language with an indeterminate subject matter is neither compositional nor bivalent.

上午8:00 | | | Latest Results for Synthese |

**Abstract**

One way that philosophers have attempted to defend free will against the threat of fatalism and against the threat from divine beliefs has been to endorse *timelessness* views (about propositions and God’s beliefs, respectively). In this paper, I argue that, in order to respond to general worries about fatalism and divine beliefs, timelessness views must appeal to the notion of *dependence*. Once they do this, however, their distinctive position as *timelessness* views becomes otiose, for the appeal to dependence, if it helps at all, would *itself* be sufficient to block worries about fatalism and divine beliefs. I conclude by discussing some implications for dialectical progress.

On quantum entanglement, counterfactuals, causality and dispositions

上午8:00 | | | Latest Results for Synthese |

**Abstract**

The existence of non-local correlations between outcomes of measurements in quantum entangled systems strongly suggests that we are dealing with some form of causation here. An assessment of this conjecture in the context of the collapse interpretation of quantum mechanics is the primary goal of this paper. Following the counterfactual approach to causation, I argue that the details of the underlying causal mechanism which could explain the non-local correlations in entangled states strongly depend on the adopted semantics for counterfactuals. Several relativistically-invariant interpretations of spatiotemporal counterfactual conditionals are discussed, and the corresponding causal stories describing interactions between parts of an entangled system are evaluated. It is observed that the most controversial feature of the postulated causal connections is not so much their non-local character as a peculiar type of circularity that affects them.

On the Sign of Fermion-Mediated Interactions. (arXiv:2009.08095v1 [cond-mat.mes-hall])

上午9:57 | | | Qing-Dong Jiang | | | quant-ph updates on arXiv.org |

We develop a unified framework for understanding the sign of fermion-mediated interactions by exploiting the symmetry classification of Green’s functions. In particular, we establish a theorem regarding the sign of fermion-mediated interactions in systems with chiral symmetry. The strength of the theorem is demonstrated within multiple examples with an emphasis on electron-mediated interactions in materials.

One from many: Estimating a function of many parameters. (arXiv:2002.02898v2 [quant-ph] UPDATED)

上午9:57 | | | Jonathan A. Gross, Carlton M. Caves | | | quant-ph updates on arXiv.org |

Difficult it is to formulate achievable sensitivity bounds for quantum multiparameter estimation. Consider a special case, one parameter from many: many parameters of a process are unknown; estimate a specific linear combination of these parameters without having the ability to control any of the parameters. Superficially similar to single-parameter estimation, the problem retains genuinely multiparameter aspects. Geometric reasoning demonstrates the conditions, necessary and sufficient, for saturating the fundamental and attainable quantum-process bound in this context.

上午9:57 | | | Hrvoje Nikolic, Josip Atelj | | | quant-ph updates on arXiv.org |

In a microscopic quantum system one cannot perform a simultaneous measurement of particle and wave properties. This, however, may not be true for macroscopic quantum systems. As a demonstration, we propose to measure the local macroscopic current passed through two slits in a superconductor. According to the theory based on the linearized Ginzburg-Landau equation for the macroscopic pseudo wave function, the streamlines of the measured current should have the same form as particle trajectories in the Bohmian interpretation of quantum mechanics. By an explicit computation we find that the streamlines should show a characteristic wiggling, which is a consequence of quantum interference.

上午9:57 | | | Leonard Mlodinow, Todd A. Brun | | | quant-ph updates on arXiv.org |

It has been shown that certain quantum walks give rise to relativistic wave equations, such as the Dirac and Weyl equations, in their long-wavelength limits. This intriguing result raises the question of whether something similar can happen in the multi-particle case. We construct a one-dimensional quantum cellular automaton (QCA) model which matches the quantum walk in the single particle case, and which approaches the quantum field theory of free fermions in the long-wavelength limit. However, we show that this class of constructions does not generalize to higher spatial dimensions in any straightforward way, and that no construction with similar properties is possible in two or more spatial dimensions. This rules out the most common approaches based on QCAs. We suggest possible methods to overcome this barrier while retaining locality.

上午9:57 | | | physics.hist-ph updates on arXiv.org |

Authors: Alessandro De Angelis, Jose M. Kenny

In 1934 Enrico Fermi accepted an invitation to deliver lectures in Argentina, Brazil and Uruguay. He arrived in Buenos Aires on July 30, lectured in Buenos Aires, Cordoba, La Plata and Montevideo, and then moved on August 18 to Sao Paulo via Santos and Rio de Janeiro; he traveled back from Rio to Naples on September 1st. His visit had a large resonance, and halls were crowded despite the fact that he lectured in Italian. The University of Buenos Aires recorded his five lectures and transcribed them in Spanish. They contain the first public presentations of the theory of beta decay and of the works on artificial radioactivity started by the via Panisperna group, but are not included in Fermi’s Collected Works edited by the Accademia dei Lincei in Rome and by the University of Chicago, although listed in the Bibliography. In this paper we present the transcription of Fermi’s five lectures in Buenos Aires, a summary of the lecture in La Plata and an extended summary of the lecture in Cordoba, translating them in English for the first time.

Two Dogmas of Dynamicism. (arXiv:2006.11400v2 [physics.hist-ph] UPDATED)

上午9:57 | | | physics.hist-ph updates on arXiv.org |

Authors: James Owen Weatherall

I critically discuss two dogmas of the “dynamical approach” to spacetime in general relativity, as advanced by Harvey Brown [Physical Relativity (2005) Oxford:Oxford University Press] and collaborators. The first dogma is that positing a “spacetime geometry” has no implications for the behavior of matter. The second dogma is that postulating the “Strong Equivalence Principle” suffices to ensure that matter is “adapted” to spacetime geometry. I conclude by discussing “spacetime functionalism”. The discussion is presented in reaction to and sympathy with recent work by James Read [“Explanation, geometry, and conspiracy in relativity theory”(20??) Thinking about Spacetime. Boston: Birkauser].

上午9:57 | | | gr-qc updates on arXiv.org |

Authors: Carlos Silva

We propose a generalization of the recently proposed holographic duality between spin networks and superstrings, and show that it can provide a possible solution to the cosmological constant problem.

上午9:57 | | | gr-qc updates on arXiv.org |

Authors: ChengGang Qin, ChengGang Shao

The Einstein Equivalence Principle carries a pivotal role in the understanding theory of gravity and spacetime. In its weak form, namely, weak equivalence principle (WEP), it implies the universality of free fall. Currently, a WEP test of relativistic form is blank in the experiments. In this work, we propose a novel scheme for the test of the WEP using frequency measurements. Our proposal consists of the comparison of high-precision clocks, comoving with the freely falling frame. In the presence of WEP violation, described by the E$\ddot{\text{o}}$tv$\ddot{\text{o}}$s parameter $\delta$, we demonstrate the feasibility to measure the potential changes of clock rates. In contrast to the traditional tests, measuring the difference on E$\ddot{\text{o}}$tv$\ddot{\text{o}}$s parameter between two materials of different compositions, our proposal allows for measuring the E$\ddot{\text{o}}$tv$\ddot{\text{o}}$s parameter for a single “test” body. Therefore, it potentially opens up a new window for the tests of the WEP. By searching for a daily variation of frequency difference between strontium optical clocks connected by optical fiber links, we obtain the upper limit of E$\ddot{\text{o}}$tv$\ddot{\text{o}}$s parameter about the Earth $\delta_{\text{E}}=(0.3\pm0.9)\times10^{-4}$.

On the Hardness of Detecting Macroscopic Superpositions. (arXiv:2009.07450v2 [quant-ph] UPDATED)

上午9:57 | | | gr-qc updates on arXiv.org |

Authors: Scott Aaronson, Yosi Atia, Leonard Susskind

When is decoherence “effectively irreversible”? Here we examine this central question of quantum foundations using the tools of quantum computational complexity. We prove that, if one had a quantum circuit to determine if a system was in an equal superposition of two orthogonal states (for example, the $|$Alive$\rangle$ and $|$Dead$\rangle$ states of Schr\”{o}dinger’s cat), then with only a slightly larger circuit, one could also $\mathit{swap}$ the two states (e.g., bring a dead cat back to life). In other words, observing interference between the $|$Alive$\rangle$and $|$Dead$\rangle$ states is a “necromancy-hard” problem, technologically infeasible in any world where death is permanent. As for the converse statement (i.e., ability to swap implies ability to detect interference), we show that it holds modulo a single exception, involving unitaries that (for example) map $|$Alive$\rangle$ to $|$Dead$\rangle$ but $|$Dead$\rangle$ to -$|$Alive$\rangle$. We also show that these statements are robust—i.e., even a $\mathit{partial}$ ability to observe interference implies partial swapping ability, and vice versa. Finally, without relying on any unproved complexity conjectures, we show that all of these results are quantitatively tight. Our results have possible implications for the state dependence of observables in quantum gravity, the subject that originally motivated this study.

Determinism and general relativity

2020年9月17日 星期四 下午2:45 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Smeenk, Chris and Wuthrich, Christian (2020) Determinism and general relativity. [Preprint]

Can we make sense of relational quantum mechanics?

2020年9月17日 星期四 下午2:44 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Ruyant, Quentin (2018) Can we make sense of relational quantum mechanics? Foundations of Physics, 48 (4). pp. 440-455. ISSN 1572-9516

2020年9月17日 星期四 上午5:44 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

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

Dissipation-Time Uncertainty Relation

2020年9月16日 星期三 下午6:00 | | | Gianmaria Falasco and Massimiliano Esposito | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Gianmaria Falasco and Massimiliano Esposito

We show that the entropy production rate bounds the rate at which physical processes can be performed in stochastic systems far from equilibrium. In particular, we prove the fundamental tradeoff ⟨S˙e⟩T≥kB between the entropy flow ⟨S˙e⟩ into the reservoirs and the mean time T to complete any process …

[Phys. Rev. Lett. 125, 120604] Published Wed Sep 16, 2020

2020年9月16日 星期三 上午2:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Sus, Adán (2020) Relativity without miracles. [Preprint]

Symmetry breaking and the emergence of path-dependence

2020年9月16日 星期三 上午2:32 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Desmond, Hugh (2017) Symmetry breaking and the emergence of path-dependence. Synthese, 194 (10). pp. 4101-4131. ISSN 0039-7857

Reeh-Schlieder, space-time foam, and the implications for neuroscience

2020年9月16日 星期三 上午2:26 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

McCabe, Gordon (2020) Reeh-Schlieder, space-time foam, and the implications for neuroscience. [Preprint]

One time, two times, or no time?

2020年9月15日 星期二 上午2:48 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wuthrich, Christian (2020) One time, two times, or no time? [Preprint]

The Dynamical Renaissance in Neuroscience

2020年9月15日 星期二 上午2:41 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Favela, Luis H. (2020) The Dynamical Renaissance in Neuroscience. [Preprint]

Is determinism completely rejected in the standard Quantum Mechanics?

2020年9月15日 星期二 上午2:31 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Bahreini, Jafar and Razmi, Habibollah and Monfared, Mahdi (2020) Is determinism completely rejected in the standard Quantum Mechanics? [Preprint]

From Time Asymmetry to Quantum Entanglement: The Humean Unification

2020年9月15日 星期二 上午2:31 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Chen, Eddy Keming (2020) From Time Asymmetry to Quantum Entanglement: The Humean Unification. [Preprint]

Weak-to-strong transition of quantum measurement in a trapped-ion system

2020年9月14日 星期一 上午8:00 | | | Nir Davidson | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 14 September 2020; doi:10.1038/s41567-020-0973-y

A weak-to-strong quantum measurement transition has been observed in a single-trapped-ion system, where the ion’s internal electronic state and its vibrational motion play the roles of the measured system and the measuring pointer.

2020年9月13日 星期日 上午2:16 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Skeels, Patrick (2020) A Tale of Two Nortons. In: UNSPECIFIED.

]]>2020年9月7日 星期一 上午8:00 | | | Angelo Bassi | | | Nature Physics – Issue – nature.com science feeds |

Nature Physics, Published online: 07 September 2020; doi:10.1038/s41567-020-1008-4The radiation emission rate from gravity-related wave function collapse is calculated and the results of a dedicated experiment at the Gran Sasso laboratory are reported, ruling out the natural parameter-free version of the Diósi–Penrose model.

上午10:17 | | | Antonio Sciarretta | | | quant-ph updates on arXiv.org |

This paper aims at reproducing quantum mechanical (QM) spin and spin entanglement results using a realist, stochastic, and local approach, without the standard QM mathematical formulation. The concrete model proposed includes the description of Stern-Gerlach apparatuses and of Bell test experiments. Single particle trajectories are explicitly evaluated as a function of a few stochastic variables that they assumedly carry on. QM predictions re retrieved as probability distributions of similarly-prepared ensembles of particles. Notably, it is shown that the proposed model, despite being both local and realist, is able to violate the Bell–CHSH inequalities by exploiting the coincidence loophole and thus intrinsically renouncing to one of the Bell’s assumptions.Leggett-Garg tests for macrorealism: interference experiments and the simple harmonic oscillator. (arXiv:2009.03856v2 [quant-ph] UPDATED)

上午10:17 | | | J.J.Halliwell, A.Bhatnagar, E.Ireland, H.Nadeem, V.Wimalaweera | | | quant-ph updates on arXiv.org |

Leggett-Garg (LG) tests for macrorealism were originally designed to explore quantum coherence on the macroscopic scale. Interference experiments and systems modelled by harmonic oscillators provide useful examples of situations in which macroscopicity has been approached experimentally and may be turned into LG tests with a dichotomic variable Q by simple partitionings of a continuous variable such as position. Applying this approach to the double-slit experiment in which a measurement at the slits and screen are considered, we find that LG violations are always accompanied by destructive interference. The converse is not true in general and we find that there are non-trivial regimes in which there is destructive interference but the two-time LG inequalities are satisfied which implies that it is in fact often possible to assign (indirectly determined) probabilities for the interferometer paths. Similar features have been observed in recent work involving a LG analysis of a Mach-Zehnder interferometer and we compare with those results. We also compare with the related problem in which a more direct determination of the paths is carried out using a variable-strength measurement at the slits and the resulting deterioration of the interference pattern is examined. We extend the analysis to the triple-slit experiment. We find examples of some surprising relationships between LG inequalities and NSIT conditions that do not exist for dichotomic variables, including a violation of the Luders bound. We analyse a two-time LG inequality for the simple harmonic oscillator. We find an analytically tractable example showing a two-time LG violation with a gaussian initial state, echoing recent results of Bose et al (Phys. Rev. Lett. 120, 210402 (2018)).The Beginning of the Nuclear Age. (arXiv:2009.05001v1 [physics.hist-ph])

上午10:17 | | | physics.hist-ph updates on arXiv.org |

Authors: M. Shifman

The article below is based on lectures delivered to new students remotely in the course of orientation. It presents the quantum theory tree from its inception a century ago till today. The main focus is on the nuclear physics – HEP branch.The philosophical underpinning of the absorber theory of radiation

上午10:17 | | |

Publication date: Available online 9 September 2020

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

Author(s): Marco ForgioneJump ship, shift gears, or just keep on chugging: Assessing the responses to tensions between theory and evidence in contemporary cosmology

上午10:17 | | |

Publication date: Available online 8 September 2020

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

Author(s): Siska De Baerdemaeker, Nora Mills BoydJosephson AC effect induced by weak gravitational field. (arXiv:2009.04967v1 [gr-qc])

上午10:17 | | | gr-qc updates on arXiv.org |

Authors: Giovanni Alberto Ummarino, Antonio Gallerati

In this paper we examine the possibility of a Josephson AC effect between two superconductors induced by the Earth’s gravitational field, making use of the gravito-Maxwell formalism. The theoretical framework exploits the symmetry between the weak field expansion of the gravitational field and the standard Maxwell formulation, combined with the Josephson junction physics. We also suggest a suitable experimental setup, analysing also the related possible difficulties in measurements.Quantum entanglement and the non-orientability of spacetime. (arXiv:2009.04990v1 [hep-th])

上午10:17 | | | gr-qc updates on arXiv.org |

Authors: Ovidiu Racorean

We argue, in the context of Ads/CFT correspondence, that the degree of entanglement on the CFTs side determines the orientation of space and time on the dual global spacetime. That is, the global spacetime dual to entangled copies of field theory is non-orientable, while the product state of the CFTs results in an orientable spacetime. As a result, disentangling the degrees of freedom between two copies of CFT implies, on the gravity side, the transition from a non-orientable spacetime to a spacetime having a definite orientation of space and time, thus an orientable spacetime. We conclude showing that topology change induced by decreasing the entanglement between two sets of degrees of freedom corresponds to a topological blow down operation.The End of a Black Hole’s Evaporation — Part I. (arXiv:2009.05016v1 [gr-qc])

上午10:17 | | | gr-qc updates on arXiv.org |

Authors: Fabio D’Ambrosio, Marios Christodoulou, Pierre Martin-Dussaud, Carlo Rovelli, Farshid Soltani

At the end of Hawking evaporation, the horizon of a black hole enters a physical region where quantum gravity cannot be neglected. The physics of this region has not been much explored. We characterise its physics and introduce a technique to study it.Generalized uncertainty principle in resonant detectors of gravitational waves. (arXiv:2005.09454v2 [gr-qc] UPDATED)

上午10:17 | | | gr-qc updates on arXiv.org |

Authors: Sukanta Bhattacharyya, Sunandan Gangopadhyay, Anirban Saha

With the direct detection of gravitational waves by advanced LIGO detector, a new “window” to quantum gravity phenomenology has been opened. At present, these detectors achieve the sensitivity to detect the length variation ($\delta L$), $\mathcal{O} \approx 10^{-17}-10^{-21}$ meter. Recently a more stringent upperbound on the dimensionless parameter $\beta_0$, bearing the effect of generalized uncertainty principle has been given which corresponds to the intermediate length scale $l_{im}= \sqrt{\beta_0} l_{pl} \sim 10^{-23} m$. Hence the flavour of the generalized uncertainty principle can be realised by observing the response of the vibrations of phonon modes in such resonant detectors in the near future. In this paper, therefore, we calculate the resonant frequencies and transition rates induced by the incoming gravitational waves on these detectors in the generalized uncertainty principle framework. It is observed that the effects of the generalized uncertainty principle bears its signature in both the time independent and dependent part of the gravitational wave-harmonic oscillator Hamiltonian. We also make an upper bound estimate of the GUP parameter.What Have Google’s Random Quantum Circuit Simulation Experiments Demonstrated about Quantum Supremacy?

上午2:26 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Horner, Jack K. and Symons, John (2020) What Have Google’s Random Quantum Circuit Simulation Experiments Demonstrated about Quantum Supremacy? [Preprint]Why the Many-Worlds Interpretation of quantum mechanics needs more than Hilbert space structure

上午2:16 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Hemmo, Meir and Shenker, Orly (2020) Why the Many-Worlds Interpretation of quantum mechanics needs more than Hilbert space structure. Scientific Challenges to Common Sense Philosophy. pp. 61-70. ISSN 9781138479982Cartography of the space of theories: an interpretational chart for fields that are both (dark) matter and spacetime

上午2:15 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Martens, Niels C.M. and Lehmkuhl, Dennis (2020) Cartography of the space of theories: an interpretational chart for fields that are both (dark) matter and spacetime. Studies in History and Philosophy of Modern Physics. ISSN 1355-2198Dark Matter = Modified Gravity? Scrutinising the spacetime–matter distinction through the modified gravity/ dark matter lens

上午2:15 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Martens, Niels C.M. and Lehmkuhl, Dennis (2020) Dark Matter = Modified Gravity? Scrutinising the spacetime–matter distinction through the modified gravity/ dark matter lens. Studies in History and Philosophy of Modern Physics. ISSN 1355-2198Classical Particle Indistinguishability, Precisely

2020年9月9日 星期三 上午8:40 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wills, James (2020) Classical Particle Indistinguishability, Precisely. [Preprint]One time, two times, or no time?

2020年9月8日 星期二 上午8:51 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wuthrich, Christian (2020) One time, two times, or no time? [Preprint]Out of Nowhere: The emergence of spacetime from causal sets

2020年9月8日 星期二 上午8:50 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wuthrich, Christian and Huggett, Nick (2020) Out of Nowhere: The emergence of spacetime from causal sets. [Preprint]

Other minds are neither seen nor inferred

2020年9月6日 星期日 上午8:00 | | | Latest Results for Synthese |

How do we know about other minds on the basis of perception? The two most common answers to this question are that we literally perceive others’ mental states, or that we infer their mental states on the basis of perceiving something else. In this paper, I argue for a different answer. On my view, we don’t perceive mental states, and yet perceptual experiences often immediately justify mental state attributions. In a slogan: other minds are neither seen nor inferred. I argue that this view offers the best explanation of our deeply equivocal intuitions about perception-based mental state attributions, and also holds substantial interest for the epistemology of perception more generally.

]]>上午10:15 | | | Yuki Inoue, Masanao Ozawa | | | quant-ph updates on arXiv.org |

Although “Heisenberg’s uncertainty principle” is represented by a rigorously proven relation about intrinsic indeterminacy in quantum states, Heisenberg’s error-disturbance relation (EDR) has been commonly believed as another aspect of the principle. However, recent developments of quantum measurement theory made Heisenberg’s EDR testable to observe its violations. Here, we study the EDR for Stern-Gerlach measurements and we conclude that their EDR is close to the theoretical optimal and surprisingly that even the original Stern-Gerlach experiment in 1922 violates Heisenberg’s EDR.A Personal History of the Hastings-Michalakis Proof of Hall Conductance Quantization. (arXiv:2009.01645v1 [physics.hist-ph])

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

Authors: M. B. Hastings

This is a personal history of the Hastings-Michalakis proof of quantum Hall conductance quantization.Particles, Fields, and the Measurement of Electron Spin. (arXiv:2007.00619v2 [quant-ph] UPDATED)

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

Authors: Charles T. Sebens

This article compares treatments of the Stern-Gerlach experiment across different physical theories, building up to a novel analysis of electron spin measurement in the context of classical Dirac field theory. Modeling the electron as a classical rigid body or point particle, we can explain why the entire electron is always found at just one location on the detector (uniqueness) but we cannot explain why there are only two locations where the electron is ever found (discreteness). Using non-relativistic or relativistic quantum mechanics, we can explain both uniqueness and discreteness. Moving to more fundamental physics, both features can be explained within a quantum theory of the Dirac field. In a classical theory of the Dirac field, the rotating charge of the electron can split into two pieces that each hit the detector at a different location. In this classical context, we can explain a feature of electron spin that is often described as distinctively quantum (discreteness) but we cannot explain another feature that could be explained within any of the other theories (uniqueness).Sequential dynamics of complex networks in mind: Consciousness and creativity

上午10:15 | | | 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: Available online 29 August 2020

**Source:** Physics Reports

Author(s): Mikhail I. Rabinovich, Michael A. Zaks, Pablo VaronaTesting gravity with cold atom interferometry: Results and prospects. (arXiv:2009.01484v1 [gr-qc])

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

Authors: Guglielmo M. Tino

Atom interferometers have been developed in the last three decades as new powerful tools to investigate gravity. Here I describe past and ongoing experiments with an outlook on what I think are the main prospects in this field and the potential to search for new physics.An Exact False Vacuum Decay Rate. (arXiv:2009.01535v1 [hep-th])

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

Authors: Victor Guada, Miha Nemevšek

We discuss an exact false vacuum decay rate at one loop for a real and complex scalar field in a quartic-quartic potential with two tree-level minima. The bounce solution is used to compute the functional determinant from both fluctuations. We obtain the finite product of eigenvalues and remove translational zero modes. The orbital modes are regularized with the zeta function and we end up with an complete decay rate after renormalization. We derive simple expansions in the thin and thick wall limits and investigate their validity.Predictive power of grand unification from quantum gravity. (arXiv:1909.07318v2 [hep-th] UPDATED)

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

Authors: Astrid Eichhorn, Aaron Held, Christof Wetterich

If a grand-unified extension of the asymptotically safe Reuter fixed-point for quantum gravity exists, it determines free parameters of the grand-unified scalar potential. All quartic couplings take their fixed-point values in the trans-Planckian regime. They are irrelevant parameters that are, in principle, computable for a given particle content of the grand unified model. In turn, the direction of spontaneous breaking of the grand-unified gauge symmetry becomes predictable. For the flow of the couplings below the Planck mass, gauge and Yukawa interactions compete for the determination of the minimum of the effective potential.Testing ER=EPR. (arXiv:2002.08178v2 [hep-th] UPDATED)

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

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

We discuss a few tests of the ER=EPR proposal. We consider certain conceptual issues as well as explicit physical examples that could be experimentally realized. In particular, we discuss the role of the Bell bounds, the large N limit, as well as the consistency of certain theoretical assumptions underlying the ER=EPR proposal. As explicit tests of the ER=EPR proposal we consider limits coming from the entropy-energy relation and certain limits coming from measurements of the speed of light as well as measurements of effective weights of entangled states. We also discuss various caveats of such experimental tests of the ER=EPR proposal.The cosmological constant and the use of cutoffs. (arXiv:2009.00728v1 [hep-th] CROSS LISTED)

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

Authors: John F. Donoghue

Of the contributions to the cosmological constant, zero-point energy and self energy contributions scale as $\Lambda^4$ where $\Lambda$ is an ultraviolet cutoff used to regulate the calculations. I show that such contributions vanish when calculated in perturbation theory. This demonstration uses a little-known modification to perturbation theory found by Honerkamp and Meetz and by Gerstein, Jackiw, Lee and Weinberg which comes into play when using cutoffs and interactions with multiple derivatives, as found in chiral theories and gravity. In a path integral treatment, the new interaction arises from the path integral measure. This reduces the sensitivity of the cosmological constant to the high energy cutoff significantly, although it does not resolve the cosmological constant problem. The feature removes one of the common motivations for supersymmetry. It also calls into question some of the results of the Asymptotic Safety program. Covariance and quadratic cutoff dependence are also briefly discussed.Distinguishing topological and causal explanation

上午4:00 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Ross, Lauren N. (2020) Distinguishing topological and causal explanation. [Preprint]The non-ideal theory of the Aharonov–Bohm effect

上午3:59 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Dougherty, John (2020) The non-ideal theory of the Aharonov–Bohm effect. Synthese. ISSN 1573-0964Effective Theories and Infinite Idealizations: A Challenge for Scientific Realism

上午3:58 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Rivat, Sébastien (2020) Effective Theories and Infinite Idealizations: A Challenge for Scientific Realism. [Preprint]Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors

2020年9月3日 星期四 下午6:00 | | | A. Vinante, M. Carlesso, A. Bassi, A. Chiasera, S. Varas, P. Falferi, B. Margesin, R. Mezzena, and H. Ulbricht | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): A. Vinante, M. Carlesso, A. Bassi, A. Chiasera, S. Varas, P. Falferi, B. Margesin, R. Mezzena, and H. Ulbricht

Despite the unquestionable empirical success of quantum theory, witnessed by the recent uprising of quantum technologies, the debate on how to reconcile the theory with the macroscopic classical world is still open. Spontaneous collapse models are one of the few testable solutions so far proposed. I…

[Phys. Rev. Lett. 125, 100404] Published Thu Sep 03, 2020Finite-Time Landauer Principle

2020年9月3日 星期四 下午6:00 | | | Karel Proesmans, Jannik Ehrich, and John Bechhoefer | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Karel Proesmans, Jannik Ehrich, and John Bechhoefer

Entropy produced by erasure of information in finite time can be minimized regardless of the final state by the use of optimal protocols that control the potential landscape.

[Phys. Rev. Lett. 125, 100602] Published Thu Sep 03, 2020Norton’s material theory of analogy

2020年9月3日 星期四 下午1:38 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Bartha, Paul (2020) Norton’s material theory of analogy. In: UNSPECIFIED.Understanding Quantum Mechanics (Beyond Metaphysical Dogmatism and Naive Empiricism)

2020年9月3日 星期四 下午1:35 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

de Ronde, Christian (2020) Understanding Quantum Mechanics (Beyond Metaphysical Dogmatism and Naive Empiricism). [Preprint]Particles, fields, and the measurement of electron spin

2020年9月3日 星期四 上午8:00 | | | Latest Results for Synthese |

This article compares treatments of the Stern–Gerlach experiment across different physical theories, building up to a novel analysis of electron spin measurement in the context of classical Dirac field theory. Modeling the electron as a classical rigid body or point particle, we can explain why the entire electron is always found at just one location on the detector (uniqueness) but we cannot explain why there are only two locations where the electron is ever found (discreteness). Using non-relativistic or relativistic quantum mechanics, we can explain both uniqueness and discreteness. Moving to more fundamental physics, both features can be explained within a quantum theory of the Dirac field. In a classical theory of the Dirac field, the rotating charge of the electron can split into two pieces that each hit the detector at a different location. In this classical context, we can explain a feature of electron spin that is often described as distinctively quantum (discreteness) but we cannot explain another feature that could be explained within any of the other theories (uniqueness).Meaning relativism and subjective idealism

2020年9月1日 星期二 上午8:00 | | | Latest Results for Synthese |

The paper discusses an objection, put forward by—among others—John McDowell, to Kripke’s Wittgenstein’s non-factualist and relativist view of semantic discourse. The objection goes roughly as follows: while it is usually possible to be a relativist about a given domain of discourse without being a relativist about anything else, relativism about semantic discourse entails global relativism, which in turn entails subjective idealism, which we can reasonably assume to be false. The paper’s first section sketches Kripke’s Wittgenstein’s ideas about semantic discourse and gives a fully explicit formulation of the objection. The second section describes and briefly discusses the formal apparatus needed to evaluate the objection—which is basically equivalent to John MacFarlane’s recent development of David Kaplan’s classic semantic framework. Finally, the third section explains in detail why the objection fails. I show that even though relativism about semantic discourse does entail a form of global relativism, the relativism in question does not entail anything like Berkeleyan or Fichtean idealism. This particular kind of relativism holds that which character (in Kaplan’s sense) is associated to a given utterance depends on what MacFarlane calls “the context of assessment”.A consciousness-based quantum objective collapse model

2020年9月1日 星期二 上午8:00 | | | Latest Results for Synthese |

Ever since the early days of quantum mechanics it has been suggested that consciousness could be linked to the collapse of the wave function. However, no detailed account of such an interplay is usually provided. In this paper we present an objective collapse model (a variation of the Continuous Spontaneous Location model) where the collapse operator depends on integrated information, which has been argued to measure consciousness. By doing so, we construct an empirically adequate scheme in which superpositions of conscious states are dynamically suppressed. Unlike other proposals in which “consciousness causes the collapse of the wave function,” our model is fully consistent with a materialistic view of the world and does not require the postulation of entities suspicious of laying outside of the quantum realm.A challenge for Super-Humeanism: the problem of immanent comparisons

2020年9月1日 星期二 上午8:00 | | | Latest Results for Synthese |

According to the doctrine of Super-Humeanism (Esfeld in Synthese. http://dx.doi.org/10.1007/s11229-017-1426-8, 2017), the world’s mosaic consists only of permanent matter points and changing spatial relations, while all the other entities and features figuring in scientific theories are nomological parameters, whose role is merely to build the best law system. In this paper, I develop an argument against Super-Humeanism by pointing out that it is vulnerable to and does not have the resources to solve the well-known problem of immanent comparisons. Firstly, I show that it cannot endorse a fundamentalist solution à la Lewis, since its two pillars—a minimalist ontology and a best system account of lawhood—would generate, together, a tedious problem of internal coherence. Secondly, I consider anti-fundamentalist strategies, proposed within Humeanism, and find them inapplicable to the Super-Humean doctrine. The concern is that, since it is impossible to choose the best law system within Super-Humeanism, this doctrine may be charged with incoherence.On the Classification between ψ−Ontic and ψ−Epistemic Ontological Models

2020年8月31日 星期一 下午1:13 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Oldofredi, Andrea and López, Cristian (2020) On the Classification between ψ−Ontic and ψ−Epistemic Ontological Models. [Preprint]Objective Consequentialism and the Plurality of Chances

2020年8月29日 星期六 下午3:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

Wroński, Leszek (2020) Objective Consequentialism and the Plurality of Chances. [Preprint]

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