Weekly Papers on Quantum Foundations (50)

上午6:29 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Heylen, Jan (2010) Descriptions and Unknowability. Analysis, 70 (1). pp. 50-52.
2019年12月20日 星期五 下午6:00 | Konstantin Beyer, Kimmo Luoma, and Walter T. Strunz | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Author(s): Konstantin Beyer, Kimmo Luoma, and Walter T. Strunz

We address the question of verifying the quantumness of thermal machines. A Szilárd engine is truly quantum if its work output cannot be described by a local hidden state model, i.e., an objective local statistical ensemble. Quantumness in this scenario is revealed by a steering-type inequality whic…

[Phys. Rev. Lett. 123, 250606] Published Fri Dec 20, 2019

2019年12月20日 星期五 下午4:21 | David Edward Bruschi, Benjamin Morris, Ivette Fuentes | quant-ph updates on arXiv.org

We investigate the quantum thermodynamical properties of localised relativistic quantum fields, and how they can be used as quantum thermal machines. We study the efficiency and power of energy transfer between the classical gravitational degrees of freedom, such as the energy input due to the motion of boundaries or an impinging gravitational wave, and the excitations of a confined quantum field. We find that the efficiency of energy transfer depends dramatically on the input initial state of the system. Furthermore, we investigate the ability of the system to extract energy from a gravitational wave and store it in a battery. This process is inefficient in optical cavities but is significantly enhanced when employing trapped Bose Einstein condensates. We also employ standard fluctuation results to obtain the work probability distribution, which allows us to understand how the efficiency is related to the dissipation of work. Finally, we apply our techniques to a setup where an impinging gravitational wave excites the phononic modes of a Bose Einstein condensate. We find that, in this case, the percentage of energy transferred to the phonons approaches unity after a suitable amount of time. These results suggest that, in the future, it might be possible to explore ways to exploit relativistic phenomena to harvest energy.

2019年12月20日 星期五 下午4:21 | Stanisław Sołtan, Mateusz Frączak, Wolfgang Belzig, Adam Bednorz | quant-ph updates on arXiv.org

Conservation principles are essential to describe and quantify mechanical processes. Classically, the conservation holds objectively because the description of reality can be considered independent of observation. In quantum mechanics, however, invasive observations change quantities drastically, even those conserved classically. Interestingly, we find that the non-conservation is manifest even in weakly measured correlations if some of the observables do not commute with the conserved quantity. Our observations show that applications of conservation laws in quantum mechanics should be considered in their specific measurement context.

2019年12月20日 星期五 下午4:21 | 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 December 2019

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

Author(s): Thomas Pashby

Abstract

This paper develops an approach to the interpretation of quantum mechanics inspired by the philosophy of Howard Stein. Taking up Stein’s (1994) call to schematize the observer and the observation, I introduce a class of observables called ‘sensibles’ which provide a means to assign probabilities to an observer’s experiences of experimental phenomena. In particular, sensibles provide an assignment of probabilities to an event space that, while satisfying the demands of probability theory, also allows for an interpretation of these events as occurring at definite space-time regions. On this understanding, the experimental events to which probabilities are ascribed are conditional occurrences—types of events which occur at a definite location in a specific experimental context. This proposal differs from dynamical collapse theories such as GRWf since these sensibles are genuine quantum observables arising from the unitary dynamics of the theory. I conclude with some remarks on the import of Stein’s philosophy for the measurement problem.

Authors: Itay M. BlochCsaba CsákiMichael GellerTomer Volansky

We propose a novel explanation for the smallness of the observed cosmological constant (CC). Regions of space with a large CC are short lived and are dynamically driven to crunch soon after the end of inflation. Conversely, regions with a small CC are metastable and long lived and are the only ones to survive until late times. While the mechanism assumes many domains with different CC values, it does not result in eternal inflation nor does it require a long period of inflation to populate them. We present a concrete dynamical model, based on a super-cooled first order phase transition in a hidden conformal sector, that may successfully implement such a crunching mechanism. We find that the mechanism can only solve the CC problem up to the weak scale, above which new physics, such as supersymmetry, is needed to solve the CC problem all the way to the UV cutoff scale. The absence of experimental evidence for such new physics already implies a mild little hierarchy problem for the CC. Curiously, in this approach the weak scale arises as the geometric mean of the temperature in our universe today and the Planck scale, hinting on a new “CC miracle”, motivating new physics at the weak scale independent of electroweak physics. We further predict the presence of new relativistic degrees of freedom in the CFT that should be visible in the next round of CMB experiments. Our mechanism is therefore experimentally falsifiable and predictive.

2019年12月20日 星期五 下午4:21 | gr-qc updates on arXiv.org

Authors: Luis R. Diaz-BarronM. Sabido

In this paper we study the “ungravity” modifications to the Friedmann equations. By using the first law of thermodynamics and the modified entropy area relationship derived from the “ungravity” contributions to the Schwarzschild black hole, we obtain modifications to the Friedmann equation that in the late time regime gives an effective cosmological constant. Therefore, this simple model can provide an “ungravity” origin to the cosmological constant $\Lambda$.

2019年12月20日 星期五 下午4:21 | gr-qc updates on arXiv.org

Authors: T. P. Shestakova

The paper is devoted to some of the difficulties which the Wheeler – DeWitt quantum geometrodynamics encountered, in particular, a strong mathematical proof that this theory is gauge-invariant, the definition of the wave function of the Universe through a path integral and the illegality of asymptotic boundary conditions in quantum gravity, the derivation of the Wheeler – DeWitt equation from the path integral and the equivalence of the Dirac quantization scheme with other approaches, the problem of definition of physical states in quantum gravity, possible realizations of the Everett concept of “relative states”. The problems are rarely discussed in the literature. They are related with the guiding idea that quantum theory of gravity must gauge invariant. It will lead to the question if it is possible to achieve this goal in a mathematically consistent way.

Authors: Carolyn E. WoodMagdalena Zych

Composite particles — atoms, molecules, or microspheres — are promising for testing joint quantum and general relativistic effects, macroscopic limits of quantum mechanics, and searching for new physics. However, all studies of the free propagation of these particles found they delocalize into separate internal energy components, destroying their spatial coherence, rendering them unsuitable for experimental applications. Here we provide a solution to this problem. We formulate a missing uncertainty inequality for configuration space variables, derive states that minimize it, and prove they fully overcome the delocalization. Beyond addressing an open theory question and a pressing issue for next generation experiments, our results pave the way to a systematic exploration of new configuration-space uncertainty principles, with further experimental applications.

2019年12月17日 星期二 下午6:00 | Philippe Faist, Takahiro Sagawa, Kohtaro Kato, Hiroshi Nagaoka, and Fernando G. S. L. Brandão | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Author(s): Philippe Faist, Takahiro Sagawa, Kohtaro Kato, Hiroshi Nagaoka, and Fernando G. S. L. Brandão

The resource theory of thermal operations, an established model for small-scale thermodynamics, provides an extension of equilibrium thermodynamics to nonequilibrium situations. On a lattice of any dimension with any translation-invariant local Hamiltonian, we identify a large set of translation-inv…

[Phys. Rev. Lett. 123, 250601] Published Tue Dec 17, 2019

2019年12月17日 星期二 上午7:39 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Tappenden, Paul (2019) Everett’s Multiverse and the World as Wavefunction. Quantum Reports, 1 (1). pp. 119-129.
2019年12月17日 星期二 上午7:32 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Gozzano, Simone (2019) Necessitarianism and Dispositions. [Preprint]
2019年12月17日 星期二 上午7:26 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
McCoy, C.D. (2019) Did the Universe Have a Chance? Philosophy of Science, 86 (5). pp. 1262-1272.
2019年12月15日 星期日 下午4:18 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Wilce, Alexander (2019) Dynamical states and the conventionality of (non-) classicality. [Preprint]
2019年12月15日 星期日 下午4:17 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Dorato, Mauro and Wittmann, Marc (2019) The phenomenology and cognitive neuroscience of experienced temporality. [Preprint]

Rethinking Superdeterminism

Quantum mechanics has irked physicists ever since its conception more than 100 years ago. While some of the misgivings, such as it being unintuitive, are merely aesthetic, quantum mechanics has one serious shortcoming: it lacks a physical description of the measurement process. This “measurement problem” indicates that quantum mechanics is at least an incomplete theory — good as far as it goes, but missing a piece — or, more radically, is in need of complete overhaul.
Here we describe an approach which may provide this sought-for completion or replacement: Superdeterminism. A superdeterministic theory is one which violates the assumption of Statistical Independence (that distributions of hidden variables are independent of measurement settings). Intuition suggests that Statistical Independence is an essential ingredient of any theory of science (never mind physics), and for this reason Superdeterminism is typically discarded swiftly in any discussion of quantum foundations.
The purpose of this paper is to explain why the existing objections to Superdeterminism are based on experience with classical physics and linear systems, but that this experience misleads us. Superdeterminism is a promising approach not only to solve the measurement problem, but also to understand the apparent nonlocality of quantum physics. Most importantly, we will discuss how it may be possible to test this hypothesis in an (almost) model independent way.

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