Weekly Papers on Quantum Foundations (34)

上午8:00 | Latest Results for Synthese

Abstract

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”.

上午8:00 | Latest Results for Synthese

Abstract

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.

Abstract

According to the doctrine of Super-Humeanism (Esfeld in Synthese. http://sci-hub.tw/10.1007/s11229-017-1426-82017), 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.

上午8:34 | Fabio Anza, James P. Crutchfield | quant-ph updates on arXiv.org

A quantum system’s state is identified with a density matrix. Though their probabilistic interpretation is rooted in ensemble theory, density matrices embody a known shortcoming. They do not completely express an ensemble’s physical realization. Conveniently, when working only with the statistical outcomes of projective and positive operator-valued measurements this is not a hindrance. To track ensemble realizations and so remove the shortcoming, we explore geometric quantum states and explain their physical significance. We emphasize two main consequences: one in quantum state manipulation and one in quantum thermodynamics.

上午8:34 | Fabio Anza, James P. Crutchfield | quant-ph updates on arXiv.org

Building on parallels between geometric quantum mechanics and classical mechanics, we explore an alternative basis for quantum thermodynamics that exploits the differential geometry of the underlying state space. We develop both microcanonical and canonical ensembles, introducing continuous mixed states as distributions on the manifold of quantum states. We call out the experimental consequences for a gas of qudits. We define quantum heat and work in an intrinsic way, including single-trajectory work, and reformulate thermodynamic entropy in a way that accords with classical, quantum, and information-theoretic entropies. We give both the First and Second Laws of Thermodynamics and Jarzynki’s Fluctuation Theorem. The result is a more transparent physics, than conventionally available, in which the mathematical structure and physical intuitions underlying classical and quantum dynamics are seen to be closely aligned.

上午8:34 | A. Matzkin, D. Sokolovski | quant-ph updates on arXiv.org

Wigner Friend scenarios — in which an external agent describes quantum mechanically a laboratory in which a Friend is making a measurement — give rise to possible inconsistencies due to the ambiguous character of quantum measurements. In this work, we investigate Wigner Friend scenarios in which the external agents can probe in a non-invasive manner the dynamics inside the laboratories. We examine probes that can be very weakly coupled to the systems measured by the Friends, or to the pointers or environments inside the laboratories. These couplings, known as Weak Measurements, are asymptotically small and do not change the outcomes obtained by the Friends nor their probabilities. Within our scheme, we show that the weakly coupled probes indicate to the external agents how to obtain consistent predictions, irrespective of the possible inconsistencies of quantum measurement theory. These non-invasive couplings could be implemented with present-day technologies.

上午8:34 | Jan de Boer, Victor Godet, Jani Kastikainen, Esko Keski-Vakkuri | quant-ph updates on arXiv.org

One of the key tasks in physics is to perform measurements in order to determine the state of a system. Often, measurements are aimed at determining the values of physical parameters, but one can also ask simpler questions, such as “is the system in state A or state B?”. In quantum mechanics, the latter type of measurements can be studied and optimized using the framework of quantum hypothesis testing. In many cases one can explicitly find the optimal measurement in the limit where one has simultaneous access to a large number $n$ of identical copies of the system, and estimate the expected error as $n$ becomes large. Interestingly, error estimates turn out to involve various quantum information theoretic quantities such as relative entropy, thereby giving these quantities operational meaning.

In this paper we consider the application of quantum hypothesis testing to quantum many-body systems and quantum field theory. We review some of the necessary background material, and study in some detail the situation where the two states one wants to distinguish are parametrically close. The relevant error estimates involve quantities such as the variance of relative entropy, for which we prove a new inequality. We explore the optimal measurement strategy for spin chains and two-dimensional conformal field theory, focusing on the task of distinguishing reduced density matrices of subsystems. The optimal strategy turns out to be somewhat cumbersome to implement in practice, and we discuss a possible alternative strategy and the corresponding errors.

Authors: Olivier Rousselle

The Copenhagen interpretation has been the subject of much criticism, notably by De Broglie and Einstein, because it contradicts the principles of causality and realism. The aim of this essay is to study the wave mechanics as an alternative to traditional quantum mechanics, in the continuity of the ideas of Louis de Broglie: the pilot wave theory of De Broglie (where each particle is associated with a wave which guides it), De Broglie-Bohm theory, stochastic electrodynamics (where the stochastic character of particles is caused by the energy field of the fluctuating vacuum), and the analogies between quantum mechanics and hydrodynamics.

上午8:33 | 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 20 August 2020

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

Author(s): Niels S. Linnemann

上午8:33 | 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 20 August 2020

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

Author(s): R. Muciño, E. Okon

Authors: M. B. Paranjape

The epitome of acausal or anti-chronological behaviour would be to see a clock running backwards in time. In this essay we point out that this is indeed possible, but there is no problem with causality. What you see isn’t what is really happening. Locally, causality is always respected. However our observation should be cause for pause to astronomers and cosmologists, who strictly observe events occurring at very large distances or very long ago and certainly not locally. It can be that what you see isn’t what you necessarily get.

Authors: Tao ZhuAnzhong Wang

The self-dual spacetime was derived from the mini-superspace approach, based on the polymerization quantization procedure in loop quantum gravity (LQG). Its deviation from the Schwarzschild spacetime is characterized by the polymeric function $P$, purely due to the geometric quantum effects from LQG. In this paper, we consider the observational constraints imposed on $P$ by using the solar system experiments and observations. For this purpose, we calculate in detail the effects of $P$ on astronomical observations conducted in the Solar system, including the deflection angle of light by the Sun, gravitational time delay, perihelion advance, and geodetic precession. The observational constraints are derived by confronting the theoretical predictions with the most recent observations. Among these constraints, we find that the tightest one comes from the measurement of the gravitational time delay by the Cassini mission, which yields $0<P<5.5\times 10^{-6}$. In addition, we also discuss the potential constraint that can be obtained in the near future by the joint European-Japanese BepiColombo project and show that it could significantly improve the current constraints.

Authors: Serhii Samokhvalov

In this article we consider the problem to what extent the motion of gauge-charged matter that generates the gravitational field can be arbitrary, as well as what equations are superimposed on the gauge field due to conditions of compatibility of gravitational field equations. Considered problem is analyzed from the point of view symmetry of the theory with respect to the generalized gauge deformed groups without specification of Lagrangians.

In particular it is shown, that the motion of uncharged particles along geodesics of Riemannian space is inherent in an extremely wide range of theories of gravity and is a consequence of the gauge translational invariance of these theories under the condition of fulfilling equations of gravitational field. In the cause of gauge-charged particles, the Lorentz force, generalized for gauge-charged matter, appear in equations of mouton as a consequence of the gauge symmetry of the theory under the condition of fulfilling the equations of the gravitational and gauge fields. In addition, we found relationships of equations for some fields that follow from the assumption about fulfilling of equations for other fields, for example, relationships of equations of the gravitational field and the gauge field of internal symmetry which follow from the assumption about fulfilling of equations of matter fields. In particular, we obtained the identity that generalizes in the case of arbitrary gauge field (and in the presence of gauge-charged matter) the identity found by Hilbert for the electromagnetic field.

At the end of the article there is an Appendix, which briefly presents the main provisions and facts from the theory of generalized gauge deformed groups, which are the basic tool of this work.

2020年8月21日 星期五 下午3:03 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Eva, Benjamin and Hartmann, Stephan (2020) The Logic of Partial Supposition. [Preprint]
2020年8月20日 星期四 下午3:24 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Kasirzadeh, Atoosa (2020) A new role for mathematics in empirical sciences. [Preprint]
2020年8月19日 星期三 上午9:10 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Woodward, James (2020) Downward Causation and Levels. [Preprint]
2020年8月18日 星期二 上午2:12 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Bacelar Valente, Mario (2020) Informal and formal proofs, metalogic, and the groundedness problem. [Preprint]
2020年8月17日 星期一 上午8:00 | Alexander O. Sushkov | Nature Physics – Issue – nature.com science feeds

Nature Physics, Published online: 17 August 2020; doi:10.1038/s41567-020-1006-6

The presence of axion-like dark matter candidates is expected to induce an oscillating magnetic field, enhanced by a ferromagnet. Limits on the electromagnetic coupling strength of axion-like particles are reported over a mass range spanning three decades.

2020年8月17日 星期一 上午8:00 | Časlav Brukner | Nature Physics – Issue – nature.com science feeds

Nature Physics, Published online: 17 August 2020; doi:10.1038/s41567-020-0984-8

The discussion of the quantum mechanical Wigner’s friend thought experiment has regained intensity. Recent theoretical results and experimental tests restrict the possibility of maintaining an observer-independent notion of measurement outcomes.

2020年8月17日 星期一 上午8:00 | Howard M. Wiseman | Nature Physics – Issue – nature.com science feeds

Nature Physics, Published online: 17 August 2020; doi:10.1038/s41567-020-0990-x

For a scenario of two separated but entangled observers, inequalities are derived from three fundamental assumptions. An experiment shows that these inequalities can be violated if quantum evolution is controllable on the scale of an observer.

2020年8月16日 星期日 下午2:11 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
de Ronde, Christian and Massri, Cesar (2020) Relational Quantum Entanglement Beyond Non-Separable and Contextual Relativism. [Preprint]
2020年8月15日 星期六 下午3:25 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Boudry, Maarten (2020) Like Black Holes in the Sky: The Warped Epistemology of Conspiracy Theories. [Preprint]
2020年8月15日 星期六 下午3:24 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Stuart, Michael T. (2021) Telling Stories in Science: Feyerabend and Thought Experiments. [Preprint]

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