# Weekly Papers on Quantum Foundations (17,18)

 下午3:48 | Jacques Pienaar | quant-ph updates on arXiv.org

According to the subjective Bayesian interpretation of quantum mechanics (QBism), the instruments used to measure quantum systems are to be regarded as an extension of the senses of the agent who is using them, and quantum states describe the agent’s expectations for what they will experience through these extended senses. How can QBism then account for the fact that (i) instruments must be calibrated before they can be used to sense’ anything; (ii) some instruments are more precise than others; (iii) more precise instruments can lead to discovery of new systems? Furthermore, is the agent incoherent’ if they prefer to use a less precise instrument? Here we provide answers to these questions.

 下午3:48 | Cole Franks, Michael Walter | quant-ph updates on arXiv.org

Consider the action of a connected complex reductive group on a finite-dimensional vector space. A fundamental result in invariant theory states that the orbit closure of a vector v is separated from the origin if and only if some homogeneous invariant polynomial is nonzero on v. We refine this famous duality between orbit closures and invariant polynomials by showing that the following two quantities coincide: (1) the logarithm of the Euclidean distance between the orbit closure and the origin and (2) the rate of exponential growth of the ‘invariant part’ of $v^{\otimes k}$ in the semiclassical limit as k tends to infinity. We also provide generalizations of this result to projections onto highest weight vectors and isotypical components. Such semiclassical limits arise in the study of the asymptotic behavior of multiplicities in representation theory, in large deviations theory in classical and quantum statistics, and in a conjecture in invariant theory due to Mathieu. Our formula implies that they can be computed, in many cases efficiently, to arbitrary precision.

 下午3:48 | Karl Svozil | quant-ph updates on arXiv.org

This is an elaboration about the “extra” advantage of the performance of quantized physical systems over classical ones; both in terms of single outcomes as well as probabilistic predictions. From a formal point of view, it is based upon entities related to (dual) vectors in (dual) Hilbert spaces, as compared to the Boolean algebra of subsets of a set and the additive measures they support.

Authors: Marian Kupczynski

Various Bell inequalities are trivial algebraic properties satisfied by each line of particular data spreadsheets.It is surprising that their violation in some experiments, allows to speculate about the existence of nonlocal influences in Nature and to doubt the existence of the objective external physical reality. Such speculations are rooted in incorrect interpretations of quantum mechanics and in a failure of local realistic hidden variable models to reproduce quantum predictions for spin polarisation correlation experiments. These hidden variable models use counterfactual joint probability distributions of only pairwise measurable random variables to prove the inequalities. In real experiments Alice and Bob, using 4 incompatible pairs of experimental settings, estimate imperfect correlations between clicks, registered by their detectors. Clicks announce detection of photons and are coded by 1 or -1. Expectations of corresponding ,only pairwise measurable, random variables are estimated and compared with quantum predictions. These estimates violate significantly the inequalities. Since all these random variables cannot be jointly measured , a joint probability distribution of them does not exist and various Bell inequalities may not be proven. Thus it is not surprising that they are violated. Moreover,if contextual setting dependent parameters describing measuring instruments are correctly included in the description, then imperfect correlations between the clicks may be explained in a locally causal way. In this paper we review and rephrase several arguments proving that the violation of various Bell inequalities may neither justify the quantum nonlocality nor allow doubting the existence of atoms, electrons and other invisible elementary particles which are building blocks of the visible world around us including ourselves.

 下午3:48 | gr-qc updates on arXiv.org

We argue that the equations of motion of quantum field theories in curved backgrounds encode new fundamental black hole thermodynamic relations. We define new entropy variation relations. These `emerge’ through the monodromies that capture the infinitesimal changes in the black hole background produced by the field excitations. This raises the possibility of new thermodynamic relations defined as independent sums involving entropies, temperatures and angular velocities defined at every black hole horizon. We present explicit results for the sum of all horizon entropy variations for general rotating black holes, both in asymptotically at and asymptotically anti-de Sitter spacetimes in four and higher dimensions. The expressions are universal, and in most cases add up to zero. We also find that these thermodynamic summation relations apply in theories involving multi-charge black holes.

 下午3:48 | 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 26 April 2020

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

Author(s): Jonathan Bain

 下午3:48 | 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 25 April 2020

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

Author(s): Joshua Norton

 下午3:48 | 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 23 April 2020

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

 下午3:48 | 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 29 April 2020

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

Author(s): Simon Saunders

 2020年5月1日 星期五 上午8:00 | Latest Results for Synthese

### Abstract

This paper has a twofold purpose. First, it aims at highlighting one difference (albeit in degree and not in kind) in how counterfactuals work in general history, on the one hand, and in history of the natural sciences, on the other hand. As we show, both in general history and in history of science good counterfactual narratives need to be plausible, where plausibility is construed as appropriate continuity of both the antecedent and the consequent of the counterfactual with what we know about the world. However, in general history it is often possible to imagine a consequent dramatically different from the actual historical development, and yet plausible; in history of science, due to plausibility concerns, imagining a consequent far removed from the results of actual science seems more complicated. The second aim of the paper is to assess whether and to what degree counterfactual histories of science can advance the cause of the so-called “contingency thesis,” namely, the claim that history of science might have followed a path leading to alternative, non-equivalent theories, as successful as the ones that we currently embrace. We distinguish various versions of the contingency thesis and argue that counterfactual histories of science support weak versions of the thesis.

 2020年4月30日 星期四 下午4:14 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Dewar, Neil (2020) Comments on Halvorson’s “The Logic in Philosophy of Science”. UNSPECIFIED.
 2020年4月30日 星期四 下午4:11 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Gábor, Hofer-Szabó (2020) Commutativity, comeasurability, and contextuality in the Kochen-Specker arguments. [Preprint]
 2020年4月27日 星期一 上午3:49 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Krause, Décio and Arenhart, Jonas R. B. (2020) Identical particles in quantum mechanics: favouring the Received View. [Preprint]
 2020年4月26日 星期日 上午7:51 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Higashi, Katsuaki (2020) Hardy relations and common cause. [Preprint]
 2020年4月26日 星期日 上午7:40 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Bacciagaluppi, Guido (2020) Quantum Mechanics, Emergence, and Decisions. [Preprint]
 2020年4月25日 星期六 上午9:23 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
James, Lucy (2020) A New Perspective On Time And Physical Laws. [Preprint]
 2020年4月22日 星期三 下午6:00 | A. J. Paige, A. D. K. Plato, and M. S. Kim | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Author(s): A. J. Paige, A. D. K. Plato, and M. S. Kim

Proper time, ideal clocks, and boosts are well understood classically, but subtleties arise in quantum physics. We show that quantum clocks set in motion via momentum boosts do not witness classical time dilation. However, using velocity boosts we find the ideal behavior in both cases, where the qua…

[Phys. Rev. Lett. 124, 160602] Published Wed Apr 22, 2020

 2020年4月21日 星期二 上午8:00 | Andrea Taroni | Nature Physics – Issue – nature.com science feeds

Nature Physics, Published online: 21 April 2020; doi:10.1038/s41567-020-0904-y

Pioneer of condensed-matter physics.

 2020年4月20日 星期一 上午8:00 | Serim Ilday | Nature Physics – Issue – nature.com science feeds

Nature Physics, Published online: 20 April 2020; doi:10.1038/s41567-020-0879-8

Biological systems are able to self-assemble in non-equilibrium conditions thanks to a continuous injection of energy. Here the authors present a tool to achieve non-equilibrium self-assembly of synthetic and biological constituents with sizes spanning three orders of magnitude.

# Discretization of the Bloch sphere, fractal invariant sets and Bell’s theorem

## Abstract

An arbitrarily dense discretization of the Bloch sphere of complex Hilbert states is constructed, where points correspond to bit strings of fixed finite length. Number-theoretic properties of trigonometric functions (not part of the quantum-theoretic canon) are used to show that this constructive discretized representation incorporates many of the defining characteristics of quantum systems: completementarity, uncertainty relationships and (with a simple Cartesian product of discretized spheres) entanglement. Unlike Meyer’s earlier discretization of the Bloch Sphere, there are no orthonormal triples, hence the Kocken–Specker theorem is not nullified. A physical interpretation of points on the discretized Bloch sphere is given in terms of ensembles of trajectories on a dynamically invariant fractal set in state space, where states of physical reality correspond to points on the invariant set. This deterministic construction provides a new way to understand the violation of the Bell inequality without violating statistical independence or factorization, where these conditions are defined solely from states on the invariant set. In this finite representation, there is an upper limit to the number of qubits that can be entangled, a property with potential experimental consequences.