# Weekly Papers on Quantum Foundations (44)

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.

Emergent Gravity from Vanishing Energy-Momentum Tensor. (arXiv:1610.08521v1 [hep-th])

on 2016-10-29 1:05am GMT

A constraint of vanishing energy-momentum tensor is motivated by a variety of perspectives on quantum gravity. We demonstrate in a concrete example how this constraint leads to a metric-independent theory in which quantum gravity emerges as a nonperturbative artifact of regularization-scale physics. We analyze a scalar theory similar to the Dirac-Born-Infeld (DBI) theory with vanishing gauge fields, with the DBI Lagrangian modulated by a scalar potential. In the limit of a large number of scalars, we explicitly demonstrate the existence of a composite massless spin-2 graviton in the spectrum that couples to matter as in Einstein gravity. We comment on the cosmological constant problem and the generalization to theories with fermions and gauge fields.

Constraining the generalized uncertainty principle with gravitational wave. (arXiv:1610.08549v1 [hep-ph])

on 2016-10-29 1:04am GMT

Various theories of quantum gravity suggest a modification in the Heisenberg uncertainty principle to a so-called generalized uncertainty principle (GUP), which produces significant modifications to different physical systems. For this reason, in this paper, we investigate the speed of graviton by utilizing two proposals for the GUP. Then, to comply event GW 150914 data, we set upper bounds on the GUP parameters. It is found that the upper limit of the GUP parameters $\beta_0$ and $\alpha_0$ are $1.44675 \times10^{10}$ and $1.35934 \times10^{-4}$.

Exotic Looped Trajectories of Photons in Three-Slit Interference. (arXiv:1610.08585v1 [quant-ph])

on 2016-10-29 1:04am GMT

The validity of the superposition principle and of Born’s rule are well-accepted tenants of quantum mechanics. Surprisingly, it has recently been predicted that the intensity pattern formed in a three-slit experiment is seemingly in contradiction with the predictions of the most conventional form of the superposition principle when exotic looped trajectories are taken into account. However, the probability of observing such paths is typically very small and thus rendering them extremely difficult to measure. In this work, we confirm the validity of Born’s rule and present the first experimental observation of these exotic trajectories as additional paths for the light by directly measuring their contribution to the formation of optical interference fringes. We accomplish this by enhancing the electromagnetic near-fields in the vicinity of the slits through the excitation of surface plasmons. This process effectively increases the probability of occurrence of these exotic trajectories, demonstrating that they are related to the near-field component of the photon’s wavefunction.

A minimalist approach to conceptualization of time in quantum theory

ScienceDirect Publication: Physics Letters A

on 2016-10-28 9:46pm GMT

Publication date: 9 December 2016
Source:Physics Letters A, Volume 380, Issue 47
Author(s): Hitoshi Kitada, Jasmina Jeknić-Dugić, Momir Arsenijević, Miroljub Dugić
Ever since Schrödinger, Time in quantum theory is postulated Newtonian for every reference frame. With the help of certain known mathematical results, we show that the concept of the so-called Local Time allows avoiding the postulate. In effect, time appears as neither fundamental nor universal on the quantum-mechanical level while being consistently attributable to every, at least approximately, closed quantum system as well as to every of its (conservative or not) subsystems.

The Relativistic Transactional Interpretation: Immune to the Maudlin Challenge

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

on 2016-10-26 5:01pm GMT

Kastner, Ruth E. (2016) The Relativistic Transactional Interpretation: Immune to the Maudlin Challenge. [Preprint]

Linking loop quantum gravity quantization ambiguities with phenomenology. (arXiv:1610.07865v1 [gr-qc])

on 2016-10-26 12:34pm GMT

Fundamental quantum gravity theories are known to be notoriously difficult to extract viable testable predictions out of. In this paper, we aim to incorporate putative quantum corrections coming from loop quantum gravity in deriving modified dispersion relations for particles on a deformed Minkowski spacetime. We show how different choices of the Immirzi parameter can, in some cases, serendipitously lead to different outcomes for such modifications, depending on the quantization scheme chosen. This allows one to differentiate between these quantization choices via testable phenomenological predictions.

Electronics: Quantum bits wired up

Nature – Issue – nature.com science feeds

on 2016-10-26 12:00am GMT

Electronics: Quantum bits wired up

Nature 538, 7626 (2016). doi:10.1038/538431e

Scientists have demonstrated a device that can interconnect as many as 100 qubits — the units of information future quantum computers will use to perform calculations that are impossible for conventional computers.The ‘quantum socket’ — built by Matteo Mariantoni at the University of Waterloo

Reality of the quantum state: Towards a stronger ψ-ontology theorem

PRA: Fundamental concepts

on 2016-10-24 2:00pm GMT

Author(s): Shane Mansfield

The Pusey-Barrett-Rudolph (PBR) no-go theorem provides an argument for the reality of the quantum state by ruling out ψ-epistemic ontological theories, in which the quantum state is of a statistical nature. It applies under an assumption of preparation independence, the validity of which has been su…

[Phys. Rev. A 94, 042124] Published Mon Oct 24, 2016

Wigner Functions for Arbitrary Quantum Systems

PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

on 2016-10-24 2:00pm GMT

Author(s): Todd Tilma, Mark J. Everitt, John H. Samson, William J. Munro, and Kae Nemoto

The possibility of constructing a complete, continuous Wigner function for any quantum system has been a subject of investigation for over 50 years. A key system that has served to illustrate the difficulties of this problem has been an ensemble of spins. Here we present a general and consistent fr…

[Phys. Rev. Lett. 117, 180401] Published Mon Oct 24, 2016

Fluctuating Work: From Quantum Thermodynamical Identities to a Second Law Equality

Recent Articles in Phys. Rev. X

on 2016-10-24 2:00pm GMT

Author(s): Álvaro M. Alhambra, Lluis Masanes, Jonathan Oppenheim, and Christopher Perry

The second law of thermodynamics plays an important role in both everyday life—think of hot coffee cooling off—and a range of scientific disciplines. Now, researchers prove a more accurate version of the second law, which states precisely by how much the hot coffee cools off, as well as being relevant to small quantum systems.

[Phys. Rev. X 6, 041017] Published Mon Oct 24, 2016

Fluctuating States: What is the Probability of a Thermodynamical Transition?

Recent Articles in Phys. Rev. X

on 2016-10-24 2:00pm GMT

Author(s): Álvaro M. Alhambra, Jonathan Oppenheim, and Christopher Perry

The second law of thermodynamics is concerned with what state formations are allowed by nature. Now, drawing inspiration from quantum information theory, researchers show that for microscopic or quantum systems, one can perform an outlawed state transformation.

[Phys. Rev. X 6, 041016] Published Mon Oct 24, 2016