Weekly Papers on Quantum Foundations (51)

上午9:24 | 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 December 2019

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

Author(s): Michael Dascal

Abstract

Frauchiger and Renner (2018) argue that no ‘single-world’ theory can consistently maintain quantum mechanical predictions for all systems. Following Bub (Bub, 2017; Bub, 2018; Bub and Cordero, 2019), I argue here that this is overstated, and use their result to develop a framework for neo-Copenhagen theories that avoid the problem. To describe the framework I introduce two concepts, ontological information deficits, and information frames, and explore how these may ultimately be fleshed out by the theorist. I then consider some immediate worries that may be raised against the framework, and conclude by looking at how two existing theories may be seen to fit into it.

2019年12月27日 星期五 下午7:29 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Shaw, Robert (2019) Single-particle entanglement and three forms of ambiguity. [Preprint]
2019年12月25日 星期三 上午9:07 | Sounok Ghosh, Leong-Chuan Kwek, Daniel R.Terno, Sai Vinjanampathy | quant-ph updates on arXiv.org

Progress in testing fundamental physics relies on our ability to measure exceedingly small physical quantities. Using a $^{40}$Ca$^{+}$ trapped ion system as an example we show that an exceedingly weak synthetic magnetic field (at the scale of $10^{-19}$ T) can be measured with current technology. This improved sensitivity can be used to test the effects of spin coupling that affect the equivalence principle and, if present, may impact the performance of the proposed entangled optical clocks arrays.

2019年12月25日 星期三 上午9:07 | Berry Groisman, Michael Mc Gettrick, Mehdi Mhalla, Marcin Pawlowski | quant-ph updates on arXiv.org

It has been shown elsewhere that quantum resources can allow us to achieve a family of equilibria that can have sometimes a better social welfare, while guaranteeing privacy. We use graph games to propose a way to build non-cooperative games from graph states, and we show how to achieve an unlimited improvement with quantum advice compared to classical advice.

2019年12月25日 星期三 上午9:07 | Augustin Vanrietvelde, Philipp A Hoehn, Flaminia Giacomini, Esteban Castro-Ruiz | quant-ph updates on arXiv.org

Treating reference frames fundamentally as quantum systems is inevitable in quantum gravity and also in quantum foundations once considering laboratories as physical systems. Both fields thereby face the question of how to describe physics relative to quantum reference systems and how the descriptions relative to different such choices are related. Here, we exploit a fruitful interplay of ideas from both fields to begin developing a unifying approach to transformations among quantum reference systems that ultimately aims at encompassing both quantum and gravitational physics. In particular, using a gravity inspired symmetry principle, which enforces physical observables to be relational and leads to an inherent redundancy in the description, we develop a perspective-neutral structure, which contains all frame perspectives at once and via which they are changed. We show that taking the perspective of a specific frame amounts to a fixing of the symmetry related redundancies in both the classical and quantum theory and that changing perspective corresponds to a symmetry transformation. We implement this using the language of constrained systems, which naturally encodes symmetries. Within a simple one-dimensional model, we recover some of the quantum frame transformations of arXiv:1712.07207, embedding them in a perspective-neutral framework. Using them, we illustrate how entanglement and classicality of an observed system depend on the quantum frame perspective. Our operational language also inspires a new interpretation of Dirac and reduced quantized theories within our model as perspective-neutral and perspectival quantum theories, respectively, and reveals the explicit link between them. In this light, we suggest a new take on the relation between a `quantum general covariance’ and the diffeomorphism symmetry in quantum gravity.

2019年12月25日 星期三 上午9:07 | Jeffrey H. Shapiro | quant-ph updates on arXiv.org

Superposition and entanglement, the quintessential characteristics of quantum physics, have been shown to provide communication, computation, and sensing capabilities that go beyond what classical physics will permit. It is natural, therefore, to explore their application to radar, despite the fact that decoherence—caused by the loss and noise encountered in radar sensing—destroys these fragile quantum properties. This paper tells the story of “quantum illumination”, an entanglement-based approach to quantum radar, from its inception to its current understanding. Remarkably, despite loss and noise that destroy its initial entanglement, quantum illumination does offer a target-detection performance improvement over a classical radar of the same transmitted energy. A realistic assessment of that improvement’s utility, however, shows that its value is severely limited. Nevertheless, the fact that entanglement can be of value on an entanglement-breaking channel—the meta-lesson of the quantum illumination story—should spur continued research on quantum radar.

2019年12月25日 星期三 上午9:07 | physics.hist-ph updates on arXiv.org

Authors: Christopher A. FuchsBlake C. Stacey

In the last five years of his life Itamar Pitowsky developed the idea that the formal structure of quantum theory should be thought of as a Bayesian probability theory adapted to the empirical situation that Nature’s events just so happen to conform to a non-Boolean algebra. QBism too takes a Bayesian stance on the probabilities of quantum theory, but its probabilities are the personal degrees of belief a sufficiently-schooled agent holds for the consequences of her actions on the external world. Thus QBism has two levels of the personal where the Pitowskyan view has one. The differences go further. Most important for the technical side of both views is the quantum mechanical Born Rule, but in the Pitowskyan development it is a theorem, not a postulate, arising in the way of Gleason from the primary empirical assumption of a non-Boolean algebra. QBism on the other hand strives to develop a way to think of the Born Rule in a pre-algebraic setting, so that it itself may be taken as the primary empirical statement of the theory. In other words, the hope in QBism is that, suitably understood, the Born Rule is quantum theory’s most fundamental postulate, with the Hilbert space formalism (along with its perceived connection to a non-Boolean event structure) arising only secondarily. This paper will avail of Pitowsky’s program, along with its extensions in the work of Jeffrey Bub and William Demopoulos, to better explicate QBism’s aims and goals.

2019年12月25日 星期三 上午9:07 | gr-qc updates on arXiv.org

Authors: S. Sedigheh HashemiGhadir JafariAli Naseh

In this paper, we examine the proposed first law of holographic complexity through studying different perturbations around various spacetime backgrounds. We present a general expression for the variation of the holographic complexity on arbitrary backgrounds by an explicit covariant computation. Interestingly, the general expression can be written as a function of gravitational conserved charges reminiscent of the first law of thermodynamics.

Authors: Shu-Cheng YangWen-Biao HanGang Wang

The weak equivalence principle (WEP), which is the equivalence of gravitational and inertial mass, is the cornerstone of gravitational theory. At the local scale, WEP has been verified to considerable accuracy by satellite experiments\cite{touboul2017microscope}. On the intergalactic distance scale, we could get constraints of violation of WEP by comparing the arrival time of different particles emitted from the same source\cite{wei2015testing, wu2016testing}. Practically, $|\Delta \gamma|$, which denotes the difference of space curvature that produced by unit rest mass of different particles, is used to indicate the deviation from the weak equivalence principle. Nowadays, $|\Delta \gamma|$ has been constrained to less than $10^{-13}$ if the two different kinds of particles finally confirmed that were emitted at the same source\cite{wei2016limits}. Here we report a new estimation of $|\Delta \gamma|$ from the gravitational wave (GW) data of binary black holes(BBHs) in the LIGO-Virgo catalog GWTC-1. For GW170608, our results show that $|\Delta \gamma|$ is not larger than $2.0\times 10^{{-16}^{+2.5}_{-1.7}}$ at 90\% confidence level for logarithmic prior. While for a modified logarithmic prior, the value of $|\Delta \gamma|$ is estimated at incredible $10^{-45}$ for GW170608 at 90\% confidence level. WEP is very probably obeyed on the intergalactic distance scale for GWs.

Authors: Ricardo Gallego Torromé

Quantum systems are viewed as emergent systems from the fundamental degrees of freedom. The laws and rules of quantum mechanics are understood as an effective description, valid for the emergent systems and specially useful to handle probabilistic predictions of observables. After introducing the geometric theory of Hamilton-Randers spaces and reformulating it using Hilbert space theory, a Hilbert space structure is constructed from the Hilbert space formulation of the underlying Hamilton-Randers model and associated with the space of wave functions of quantum mechanical systems. We can prove the emergence of the Born rule from ergodic considerations. A geometric mechanism for a natural spontaneous collapse of the quantum states based on the concentration of measure phenomena as it appears in metric geometry is discussed.We show the existence of stable vacua states for the quantized matter Hamiltonian. Another consequence of the concentration of measure is the emergence of a weak equivalence principle for one of the dynamics of the fundamental degrees of freedom. We suggest that the reduction of the quantum state is driven by a gravitational type interaction.

Such interaction appears only in the dynamical domain when localization of quantum observables happens, it must be a classical interaction. We discuss the double slit experiment in the context of the framework proposed, the interference phenomena associated with a quantum system in an external gravitational potential, a mechanism explaining non-quantum locality and also provide an argument in favour of an emergent interpretation of every macroscopic time parameter. Entanglement is partially described in the context of Hamilton-Randers theory and how naturally Bell’s inequalities should be violated.

Authors: Michael BishopJaeyeong LeeDouglas Singleton

In quantum gravity it is generally thought that a modified commutator of the form $[{\hat x}, {\hat p}] = i \hbar (1 + \beta p^2)$ is sufficient to give rise to a minimum length scale. We test this assumption and find that different pairs of modified operators can lead to the same modified commutator and yet give different or even no minimal length. The conclusion is that the modification of the operators is the main factor in determining whether there is a minimal length. This fact – that it is the specific form of the modified operators which determine the existence or not of a minimal length scale – can be used to keep or reject specific modifications of the position and momentum operators in theory of quantum gravity.

2019年12月24日 星期二 上午8:00 | Baron S, Evans P. | The British Journal for the Philosophy of Science Advance Access
Abstract

Skow ([2007]), and much more recently Callender ([2017]), argue that time can be distinguished from space due to the special role it plays in our laws of nature: our laws determine the behaviour of physical systems across time, but not across space. In this work we assess the claim that the laws of nature might provide the basis for distinguishing time from space. We find that there is an obvious reason to be sceptical of the argument Skow submits for distinguishing time from space: Skow fails to pay sufficient attention to the relationship between the dynamical laws and the antecedent conditions required to establish a complete solution from the laws. Callender’s more sophisticated arguments in favour of distinguishing time from space by virtue of the laws of nature presents a much stronger basis to draw the distinction. By developing a radical reading of Callender’s view we propose a novel approach to differentiating time and space that we call temporal perspectivalism. This is the view according to which the difference between time and space is a function of the agentive perspective.

  • 1Introduction
  • 2Time as the Preferred Direction of Laws
  • 3Dynamical Laws and Antecedent Conditions
  • 4Time as the ‘Great Informer’
    • 4.1The informal argument
    • 4.2The formal argument
  • 5A Difference in the Laws?
  • 6Temporal Perspectivalism
  • 7Final Thoughts
2019年12月23日 星期一 下午7:39 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Nuño de la Rosa, Laura and Villegas, Cristina (2019) Chances and Propensities in Evo-devo. The British Journal for the Philosophy of Science.

Article written by

editor