# Weekly Papers on Quantum Foundations (33)

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

On Noncontextual, Non-Kolmogorovian Hidden Variable Theories. (arXiv:1608.03518v1 [quant-ph])

on 2016-8-12 12:52am GMT

One implication of Bell’s theorem is that there cannot in general be hidden variable models for quantum mechanics that both are noncontextual and retain the structure of a classical probability space. Thus, some hidden variable programs aim to retain noncontextuality at the cost of using a generalization of the Kolmogorov probability axioms. We generalize a theorem of Feintzeig (2015) to show that such programs are committed to the existence of a finite null cover for some quantum mechanical experiments, i.e., a finite collection of probability zero events whose disjunction exhausts the space of experimental possibilities.

A study of Aharonov-Bohm effect: from quantum electrodynamics to one particle quantum mechanics. (arXiv:1607.03501v3 [quant-ph] UPDATED)

on 2016-8-12 12:52am GMT

Authors: Benliang LiDaniel W. HewakQi Jie Wang

In this article, we start with the discussions on the Aharonov-Bohm effect then raise a plausible interpretation within the quantum electrodynamics (QED) framework. We provide a quantum treatment of the source of the electromagnetic potential and argue that the underlying mechanism in AB effect can be viewed as interactions between electrons described by QED theory where the interactions are mediated by virtual photons. On further analysis, we argue that the framework of one particle quantum mechanics (OPQM) can be shown, in general, as a mathematically approximated model which can be reformulated from QED theory. In addition, the classical Maxwell equations are derived from QED scattering process while both classical electromagnetic fields and potentials serve as mathematical tools that are constructed to approximate the interactions among elementary particles described by QED physics, i.e., neither classical fields nor potentials represent any real entities of nature. At the conclusion of this article, we make a few remarks on the hypothesis of the existence of magnetic monopoles.

Introduction to localization in quantum field theory. (arXiv:1608.02953v1 [hep-th])

on 2016-8-11 2:35am GMT

Authors: Vasily PestunMaxim Zabzine

This is the introductory chapter to the volume. We review the main idea of the localization technique and its brief history both in geometry and in QFT. We discuss localization in diverse dimensions and give an overview of the major applications of the localization calculations for supersymmetric theories. We explain the focus of the present volume.

Localization techniques in quantum field theories. (arXiv:1608.02952v1 [hep-th])

on 2016-8-11 2:35am GMT

This is the foreword to the special volume on localization techniques in quantum field theory. We summarize the individual chapters and their relation.

Taking Einstein seriously: Relativistic coupling of internal and center of mass dynamics. (arXiv:1608.03253v1 [quant-ph])

on 2016-8-11 2:34am GMT

Authors: Dennis E. KrauseInbum Lee

Einstein’s famous equation $E_{\rm rest}=mc^2$ for the rest energy of a system with mass $m$ requires that the internal energy of the system be included in $m$. Pursuing this idea using Lagrangian and Hamiltonian dynamics yields a relativistic coupling between the center of mass motion and the internal dynamics of the system. Here we explore the consequences of this coupling, first classically, where we find that the dynamics of the system is time dilated when moving relative to another inertial frame. We then apply the dynamics to a quantum 2-level atom bound in a 1-dimensional infinite potential well, and show that the coupling produces collapses and revivals in quantum interference.

Hawking versus Unruh effects, or the diffculty of slowly crossing a black hole horizon. (arXiv:1608.02532v1 [gr-qc])

on 2016-8-09 1:02am GMT

When analyzing the perception of Hawking radiation by different observers, the Hawking effect becomes mixed with the Unruh effect. The separation of both effects is not always clear in the literature. Here we propose an inconsistency-free interpretation of what constitutes a Hawking effect and what an Unruh effect. An appropriate interpretation is important in order to elucidate what sort of effects a detector might experience depending on its trajectory and the state of the quantum field. Under simplifying assumptions we introduce an analytic formula that separates these two effects. Armed with the previous interpretation we argue that for a free-falling detector to cross the horizon without experiencing high-energy effects, it is necessary that the horizon crossing is not attempted at low velocities.

Spookyfying Quantum Information is Impossible. (arXiv:1608.01695v1 [quant-ph])

on 2016-8-08 3:11am GMT

Classical information encoded in composite quantum states can be completely hidden from the reduced subsystems and may be found only in the correlations. Can the same be true for quantum information? If quantum information is hidden from subsystems and spread over quantum correlation, we call it as spookyfying of quantum information. We show that while this may still be true for some restricted sets of non-orthogonal quantum states, it is not possible for arbitrary quantum states. This result suggests that quantum qubit commitment — a stronger version of the quantum bit commitment is not possible in general. Our findings may have potential applications in secret sharing and future quantum communication protocols.

Experimental Verification of an Indefinite Causal Order. (arXiv:1608.01683v1 [quant-ph])

on 2016-8-08 3:11am GMT

Investigating the role of causal order in quantum mechanics has recently revealed that the causal distribution of events may not be a-priori well-defined in quantum theory. While this has triggered a growing interest on the theoretical side, creating processes without a causal order is an experimental task. Here we report the first decisive demonstration of a process with an indefinite causal order. To do this, we quantify how incompatible our set-up is with a definite causal order by measuring a ‘causal witness’. This mathematical object incorporates a series of measurements which are designed to yield a certain outcome only if the process under examination is not consistent with any well-defined causal order. In our experiment we perform a measurement in a superposition of causal orders – without destroying the coherence – to acquire information both inside and outside of a ‘causally non-ordered process’. Using this information, we experimentally determine a causal witness, demonstrating by almost seven standard deviations that the experimentally implemented process does not have a definite causal order.

Happiest Thoughts: Great Thought Experiments of Modern Physics

Philsci-Archive: No conditions. Results ordered -Date Deposited.

on 2016-8-07 11:26pm GMT

Peacock, Kent A. (2016) Happiest Thoughts: Great Thought Experiments of Modern Physics. In: UNSPECIFIED.