Weekly Papers on Quantum Foundations (19)

This is a list of this week’s papers on quantum foundations published in the various journals or uploaded to the preprint servers such as arxiv.org and PhilSci Archive.

Protective Measurements: Probing Single Quantum Systems. (arXiv:1505.01591v1 [quant-ph])

quant-ph updates on arXiv.org

on 2015-5-08 1:16am GMT

Authors: Tabish Qureshi (Center for Theoretical Physics, JMI, Delhi), N.D. Hari Dass (TIFR-TCIS, Hyderabad)

Making measurements on single quantum systems is considered difficult, almost impossible if the state is a-priori unknown. Protective measurements suggest a possibility to measure single quantum systems and gain some new information in the process. Protective measurement is described, both in the original and generalized form. The degree to which the system and the apparatus remain entangled in a protective measurement, is assessed. A possible experimental test of protective measurements is discussed.

Unruh versus Tolman: On the heat of acceleration. (arXiv:1505.01686v1 [gr-qc])

quant-ph updates on arXiv.org

on 2015-5-08 1:16am GMT

Authors: Detlev BuchholzRainer Verch

It is shown that the Unruh effect, i.e. the increase in temperature indicated by a uniformly accelerated thermometer in an inertial vacuum state of a quantum field, cannot be interpreted as the result of an exchange of heat with a surrounding gas of particles. Since the vacuum is spatially homogeneous in any accelerated system its temperature must be zero everywhere as a consequence of Tolman’s law. In fact, the increase of temperature of accelerated thermometers is due to systematic quantum effects induced by the local coupling between the thermometer and the vacuum. This coupling inevitably creates particles from the vacuum which transfer energy to the thermometer, gained by the acceleration, and thereby affect its readings. The temperature of the vacuum, however, remains to be zero for arbitrary accelerations.

Simple understanding of quantum weak values. (arXiv:1505.00595v1 [quant-ph])

quant-ph updates on arXiv.org

on 2015-5-05 1:44am GMT

Authors: Lupei QinWei FengXin-Qi Li

In this work we present a transparent method to revisit the concept of quantum weak values, in hope to provide a simpli?ed understanding to its associated physics and the origin of anomaly. Our analysis is based on an exact treatment by using the quantum Bayesian approach for the typical system of Stern-Gerlach setup, and makes particular connection with the recent controversial work by Ferrie and Combes [Phys. Rev. Lett. 113, 120404 (2014)]. The present work is expected to be a useful addition to resolve the controversies.

CP Violation and Baryogenesis in the Presence of Black Holes. (arXiv:1505.00472v1 [hep-th])

gr-qc updates on arXiv.org

on 2015-5-05 1:44am GMT

Authors: Tom BanksWilly Fischler

In a recent paper[1] Kundu and one of the present authors showed that there were transient but observable CP violating effects in the decay of classical currents on the horizon of a black hole, if the Lagrangian of the Maxwell field contained a CP violating angle {\theta}. In this paper we demonstrate that a similar effect can be seen in the quantum mechanics of QED: a non-trivial Berry phase in the QED wave function is produced by in-falling electric charges. We also investigate whether CP violation, of this or any other type, might be used to produce the baryon asymmetry of the universe, in models where primordial black hole decay contributes to the matter content of the present universe. This can happen both in a variety of hybrid inflation models, and in the Holographic Space-time (HST) model of inflation[2].

On the Stability of Einstein Static Universe in Doubly General Relativity Scenario. (arXiv:1505.00342v1 [gr-qc])

gr-qc updates on arXiv.org

on 2015-5-05 1:44am GMT

Authors: M. KhodadiY. HeydarzadeK. NozariF. Darabi

Rainbow gravity or doubly general relativity (DGR) is a phenomenological effective approach to quantum gravity proposed by Magueijo and Smolin \cite{Magueijo}. This model proposes a correction for the standard general relativity at the early stage of the Universe. Moreover, it prevents the initial Big-Bang singularity. In this paper, we study the rainbow gravity modifications on the stability conditions of the Einstein static Universe (ESU). Interestingly, we find that the positive energy condition of ESU in the framework of DGR scenario dictates a positive spatial curvature for the Universe. This addresses an agreement between DGR scenario and basic assumption of modern version of “Emergent Universe” proposed by Ellis and Maartens \cite{EM}. We show that DGR modifications can result in an stable Einstein static model against the linear scalar perturbations under the obtained conditions. Also, we explore the stability of ESU against the vector and tensor perturbations.

The Quest for Reality

Philosophy

on 2015-5-05 12:00am GMT

Author: Stig Stenholm
ISBN: 9780198729105
Binding: Paperback
Publication Date: 05 May 2015
Price: $34.95

Primitive ontology and quantum field theory

Latest Results for European Journal for Philosophy of Science

on 2015-5-03 12:00am GMT

Abstract

Primitive ontology is a recently much discussed approach to the ontology of quantum theory according to which the theory is ultimately about entities in 3-dimensional space and their temporal evolution. This paper critically discusses the primitive ontologies that have been suggested within the Bohmian approach to quantum field theory in the light of the existence of unitarily inequivalent representations. These primitive ontologies rely either on a Fock space representation or a wave functional representation, which are strictly speaking unambiguously available only for free systems in flat spacetime. As a consequence, it is argued that they do not constitute fundamental ontologies for quantum field theory, in contrast to the case of the Bohmian approach to quantum mechanics.

 

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