Publication date: Available online 20 March 2020

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

Author(s): James Owen Weatherall

Christian, Joy (2020) Dr. Bertlmann’s Socks in the Quaternionic World of Ambidextral Reality. [Preprint]

Author(s): Yuuya Chiba, Kenichi Asano, and Akira Shimizu

We examine how the magnetic susceptibility obtained by the quench experiment on isolated quantum systems is related to the isothermal and adiabatic susceptibilities defined in thermodynamics. Under the conditions similar to the eigenstate thermalization hypothesis, together with some additional natu…

[Phys. Rev. Lett. 124, 110609] Published Fri Mar 20, 2020

We derive a thermodynamic uncertainty relation for general open quantum systems. Open quantum dynamics can be described by a joint unitary evolution on a composite system consisting of system and environment. By considering the environmental state after the interaction, we bound counting observables on the environment by a generalized dynamical activity, which is a quantum analogue of the quantity in classical Markov processes. Remarkably, our relation holds for any open quantum systems, any counting observables, and any initial states. We apply our relation to the continuous measurement on open quantum systems to find that the quantumness of the system can enhance the precision.

The uncertainty principle lies at the heart of quantum physics, and is widely thought to be a fundamental limit on the measurement precisions of incompatible observables. Here we show that this mode of thought only pertains to the lowest order approximation of a generalized uncertainty principle, where the incompatibility between observables is interpreted as the statistical correlation. We derive out a generalized uncertainty relation which exhibits the full-order statistical correlations between observables. The new result extends the leading order linear correlation, the nature of Heisenberg type of uncertainty relations, to nonlinear correlation involved arbitrary high orders, and hence provides an alternative view to the foundation of quantum mechanics. The new finding will definitely enlarge the application of uncertainty relation in quantum information processing.

We study the wave function localization properties in a d-dimensional model of randomly spaced particles with isotropic hopping potential depending solely on Euclidean interparticle distances. Due to the generality of this model usually called the Euclidean random matrix model, it arises naturally in various physical contexts such as studies of vibrational modes, artificial atomic systems, liquids and glasses, ultracold gases and photon localization phenomena. We generalize the known Burin-Levitov renormalization group approach, formulate universal conditions sufficient for localization in such models and inspect a striking equivalence of the wave function spatial decay between Euclidean random matrices and translation-invariant long-range lattice models with a diagonal disorder.

We propose a general argument to show that if a physical system can mediate locally the generation of entanglement between two quantum systems, then it itself must be non-classical. Remarkably, we do not assume any classical or quantum formalism to describe the mediating physical system: our result follows from general information-theoretic principles, drawn from the recently proposed constructor theory of information. This argument provides the indispensable theoretical basis for recently proposed tests of non-classicality in gravity, based on witnessing gravitationally-induced entanglement in quantum probes.

Publication date: Available online 19 March 2020

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

Author(s): Flavio Del Santo

Publication date: Available online 17 March 2020

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

Author(s): David Schroeren

Authors: Cesar Gomez, Raul Jimenez

We suggest a general relation between the position of the cosmic microwave background temperature power spectrum peaks and the inflationary slow roll parameter $\epsilon$. This relation is based on interpreting the variable setting the position of the peaks as the quantum distance between the end of inflation and recombination. This distance is determined by the primordial cosmological Fisher information introduced in arXiv:2002.04294. The observational constraints set by cosmic microwave background temperature data lead to a very stringent prediction for the value of the tensor-to-scalar ratio: $r=0.01 \pm 0.002$. Future polarization data of the cosmic microwave background should be able to measure this signal and corroborate or discard our model.

Authors: Stephon Alexander, Gabriel Herczeg, Jinglong Liu, Evan McDonough

In this work we provide a link between a nearly vanishing cosmological constant and chiral symmetry. This is accomplished with a modification of General Relativity coupled to a topological field theory, namely BF theory by introducing fermions charged under the BF theory gauge group. We find that the cosmological constant sources a chiral anomaly for the fermions, providing a `technical naturalness’ explanation for the smallness of the observed cosmological constant. Applied to the early universe, we show that production of fermions during inflation can provide all the dark matter in the universe today, in the form of superheavy dark baryons.

Authors: Eduardo Bittencourt, Gabriel G. Carvalho, Iarley P. Lobo, Leandro Santana

We analyze how the hypotheses of Penrose’s singularity theorem (1965) are modified by the action of disformal transformations (defined in terms of light-like vectors) upon a given space-time metric. In particular, we investigate the transformation of the null energy condition and the existence of closed trapped surfaces in such scenario, in order to derive conditions upon the background metric and the disformal vector that guarantee the validity of Penrose’s theorem for disformal metrics. Then, we explain how to apply this technique for static and spherically symmetric space-times in general.

Authors: Dag Østvang

In this thesis, a non-standard geometric framework, the “quasi-metric” framework (QMF), is used to define relativistic space-time. The QMF consists of a 4-dimensional space-time manifold equipped with two one-parameter families of Lorentzian 4-metrics ${\bf g}_t$ and ${\bf {\bar g}}_t$ parameterized by a (unique) global time function $t$. The global time function represents one extra degenerate time dimension and it defines a “distinguished” foliation of quasi-metric space-time into spatial hypersurfaces. The metric family ${\bf {\bar g}}_t$ is found as solutions of field equations, whereas the metric family ${\bf g}_t$ is found via a local transformation ${\bf {\bar g}}_t{\rightarrow}{\bf g}_t$ and is used in the equations of motion. The role of the degenerate dimension is to describe global scale changes between gravitational and non-gravitational systems. In particular, this yields an alternative description of the expansion of the Universe. In this thesis, a quasi-metric theory of gravity is constructed. Like General Relativity, the field equations have two independent propagating dynamical degrees of freedom. However, the existence of a distinguished dynamical foliation of quasi-metric space-time into spatial hypersurfaces makes the field equations unsuitable for a standard PPN-analysis. This implies that the experimental status of the theory is not completely clear at this point in time. But the non-metric part of the theory may be tested rather independently. That is, the theory predicts that gravitational fields in vacuum and gravitationally bound bodies made of ideal gas expand like the expansion of the Universe. Several observations suggest this; e.g., the “Pioneer effect”, the mean acceleration of the Moon, the spin-down of the Earth, palaeo-tidal records, etc. Thus quasi-metric relativity has experimental support where metric theories fail.

Authors: Hikaru Kawai, Yuki Yokokura

We describe 4D evaporating black holes as quantum field configurations by solving the semi-classical Einstein equation $G_{\mu\nu}=8\pi G \langle \psi|T_{\mu\nu}|\psi \rangle$ and quantum matter fields in a self-consistent manner. As the matter fields we consider $N$ massless free scalar fields ($N$ is large). We find a spherically symmetric self-consistent solution of the metric $g_{\mu\nu}$ and state $|\psi\rangle$. Here, $g_{\mu\nu}$ is locally $AdS_2\times S^2$ geometry, and $|\psi\rangle$ provides $\langle \psi|T_{\mu\nu}|\psi \rangle=\langle0|T_{\mu\nu}|0 \rangle+T_{\mu\nu}^{(\psi)}$, where $|0\rangle$ is the ground state of the matter fields in the metric and $T_{\mu\nu}^{(\psi)}$ consists of the excitation of s-waves that describe the collapsing matter and Hawking radiation with the ingoing negative energy flow. This object is supported by a large tangential pressure $\langle0|T^\theta{}_\theta|0 \rangle$ due to the vacuum fluctuation of the bound modes with large angular momenta. This describes the interior of the black hole when the back reaction of the evaporation is considered. The black hole is a compact object with a surface (instead of horizon) that looks like a conventional black hole from the outside and eventually evaporates without a singularity. If we count the number of self-consistent configurations $\{|\psi\rangle\}$, we reproduce the area law of the entropy. This tells that the information is carried by the s-waves inside the black hole. $|\psi\rangle$ also describes the process that the negative ingoing energy flow created with Hawking radiation is superposed on the collapsing matter to decrease the total energy while the total energy density remains positive. As a special case, we consider conformal matter fields and show that the interior metric is determined by the matter content of the theory, which leads to a new weak-gravity conjecture.

Author(s): Kok Chuan Tan, Seongjeon Choi, and Hyunseok Jeong

We demonstrate that the negative volume of any s-parametrized quasiprobability, including the Glauber-Sudashan P function, can be consistently defined and forms a continuous hierarchy of nonclassicality measures that are linear optical monotones. These measures belong to an operational resource theo…

[Phys. Rev. Lett. 124, 110404] Published Thu Mar 19, 2020

Van Fraassen, Bas C. (2020) Supervenience, Logic, and Empirical Content: Commentary on Hans Halvorson, The Logic in Philosophy of Science. [Preprint]

Authors: Flavio Del Santo

A tradition handed down among physicists maintains that classical physics is a perfectly deterministic theory capable of predicting the future with absolute certainty, independently of any interpretations. It also tells that it was quantum mechanics that introduced fundamental indeterminacy into physics. We show that there exist alternative stories to be told in which classical mechanics, too, can be interpreted as a fundamentally indeterministic theory. On the one hand, this leaves room for the many possibilities of an open future, yet, on the other, it brings into classical physics some of the conceptual issues typical of quantum mechanics, such as the measurement problem. We discuss here some of the issues of an alternative, indeterministic classical physics and their relation to the theory of information and the notion of causality.

The title of our work is a paraphrase of the title of Asher Peres’ paper \textit{Unperformed experiments have no results}. We show what are the lessons to be learned from the gedankenexperiments presented by Frauchiger and Renner (claim that quantum theory cannot consistently describe the use of itself), and Brukner (a no-go theorem for observer independent facts). One has to remember Bohr’s remark “the unambiguous account of proper quantum phenomena must, in principle, include a description of all relevant features of experimental arrangement”, which specifically to the gedankenexperiments means: in all your quantum mechanical thinking about measurements, think in terms of the full quantum measurement theory. The theory sees measurement as composed of two stages: pre-measurement (entanglement, i.e. quantum correlation, of the measured system with the pointer variable), and next decoherence via interaction with an environment, which leaves a record of the result. The nature of the second stage is that the environment is beyond our control, thus the decoherence cannot be undone, neither by the original observer nor by someone else. If one uses in the description of measurement only the pre-measurement stage, there are no recorded results, and the process can be undone. We can have a quantum-marker-quantum-eraser situation. The gedankenexperiments are effectively scenarios of this type. The process described by Frauchiger and Renner is possible only if the Friends of the Wigners constrain themselves to pre-measurements. We also present a version of Bell’s inequality, which holds for hypothetical ‘outcomes’ obtained by the Friends during their (pre-)measurements. Inclusion of this notion is shown to be at odds with quantum mechanical predictions. Thus, it cannot be used in any argumentation about a quantum process which involves pre-measurements.

Publication date: Available online 17 March 2020

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

Author(s): Mordecai Waegell, Kelvin J. McQueen

Authors: Michael R. Wilczynska, John K. Webb, Matthew Bainbridge, Sarah E. I. Bosman, John D. Barrow, Robert F. Carswell, Mariusz P. Dabrowski, Vincent Dumont, Ana Catarina Leite, Chung-Chi Lee, Katarzyna Leszczynska, Jochen Liske, Konrad Marosek, Carlos J.A.P. Martins, Dinko Milakovic, Paolo Molaro, Luca Pasquini

Observations of the redshift z=7.085 quasar J1120+0641 have been used to search for variations of the fine structure constant, alpha, over the redshift range 5.5 to 7.1. Observations at z=7.1 probe the physics of the universe when it was only 0.8 billion years old. These are the most distant direct measurements of alpha to date and the first measurements made with a near-IR spectrograph. A new AI analysis method has been employed. Four measurements from the X-SHOOTER spectrograph on the European Southern Observatory’s Very Large Telescope (VLT) directly constrain any changes in alpha relative to the value measured on Earth (alpha_0). The weighted mean strength of the electromagnetic force over this redshift range in this location in the universe is da/a = (alpha_z – alpha_0)/alpha_0 = (-2.18 +/- 7.27) X 10^{-5}, i.e. we find no evidence for a temporal change from the 4 new very high redshift measurements. When the 4 new measurements are combined with a large existing sample of lower redshift measurements, a new limit on possible spatial variation of da/a is marginally preferred over a no-variation model at the 3.7 sigma level.

Authors: Hidenori Fukaya

Gravity is difficult to quantize. This is a well-known fact but its reason is given simply by non-renormalizability of the Newton constant and little is discussed why among many quantum gauge theories, gravity is special. In this essay we try to treat the gravity as one of many gauge theories, and discuss how it is special and why it is difficult to quantize.

Authors: L. Herrera

We endeavour to illustrate the physical relevance of the Landauer principle applying it to different important issues concerning the theory of gravitation. We shall first analyze, in the context of general relativity, the consequences derived from the fact, implied by Landauer principle, that information has mass. Next, we shall analyze the role played by the Landauer principle in order to understand why different congruences of observers provide very different physical descriptions of the same space–time. Finally, we shall apply the Landauer principle to the problem of gravitational radiation. We shall see that the fact that gravitational radiation is an irreversible process entailing dissipation, is a straightforward consequence of the Landauer principle and of the fact that gravitational radiation conveys information. An expression measuring the part of radiated energy that corresponds to the radiated information and an expression defining the total number of bits erased in that process, shall be obtained, as well as an explicit expression linking the latter to the Bondi news function.

Authors: Jie Jiang, Yunjiao Gao

Recently, Li and Bambi proposed a hypothesis that the event horizon of a regular black hole can be destroyed because these objects have no gravitational singularity and therefore they are not protected by the weak cosmic censorship conjecture (WCCC). In this paper, to test their hypothesis, we perform the new version of the gedanken experiments proposed by Sorce and Wald to overcharge a near extremal static electrically regular black hole. After introducing the stability condition of the spacetime and the null energy condition of matter fields, we derive the first-order and second-order perturbation inequalities of the perturbation matter fields based on the Iyer-Wald formalism. As a result, we find that these regular black holes cannot be destroyed under the second-order approximation after these two perturbation inequalities are taken into account, even though they are not protected by the WCCC. Our results indicate that there might be some deeper mechanisms to protect the event horizon of the black holes.

Authors: Kazumasa Okabayashi, Nobuyuki Asaka, Ken-ichi Nakao

The so-called black hole shadow is not a silhouette of a black hole but an image of a collapsing object or a white hole. Hence it is non-trivial whether black hole shadows merge with each other when black holes coalesce with each other. In this paper, by analyzing the null geodesic generators of the event horizon in Kastor-Traschen spacetime which describes a coalescence of black boles, we see that observers who will never see a merger of black hole shadows exist.

Abstract

This special issue of Foundations of Physics collects together articles representing some recent new perspectives on the hole argument in the history and philosophy of physics. Our task here is to introduce those new perspectives.

Author(s): M. Naghiloo, D. Tan, P. M. Harrington, J. J. Alonso, E. Lutz, A. Romito, and K. W. Murch

We use a near quantum limited detector to experimentally track individual quantum state trajectories of a driven qubit formed by the hybridization of a waveguide cavity and a transmon circuit. For each measured quantum coherent trajectory, we separately identify energy changes of the qubit as heat a…

[Phys. Rev. Lett. 124, 110604] Published Tue Mar 17, 2020

Author(s): Lorenzo Maccone and Krzysztof Sacha

We propose a time-of-arrival operator in quantum mechanics by conditioning on a quantum clock. This allows us to bypass some of the problems of previous proposals, and to obtain a Hermitian time of arrival operator whose probability distribution arises from the Born rule and which has a clear physic…

[Phys. Rev. Lett. 124, 110402] Published Mon Mar 16, 2020

Nature Physics, Published online: 16 March 2020; doi:10.1038/s41567-020-0833-9

Laboratory experiments reproduce the three-dimensional pancake-like shape of Jupiter’s vortices. The thickness of the Great Red Spot is predicted, awaiting comparison with NASA’s Juno mission.

Nature Physics, Published online: 16 March 2020; doi:10.1038/s41567-020-0836-6

Measurements of non-Hermitian photon dynamics show boundary-localized bulk eigenstates given by the non-Hermitian skin effect. A fundamental revision of the bulk–boundary correspondence in open systems is required to understand the underlying physics.

Nature Physics, Published online: 16 March 2020; doi:10.1038/s41567-020-0828-6

At high temperature, the heat diffusion in an insulator is expected to be dominated by entirely classical phonon dynamics. But theoretical study shows that the transport lifetime is subject to a quantum-mechanical bound related to the sound velocity.

Murgueitio Ramírez, Sebastián (2020) A puzzle concerning local symmetries and their empirical significance. The British Journal for the Philosophy of Science. ISSN 1464-3537

Anastopoulos, Charis (2020) Mind-body interaction and modern physics. [Preprint]

Abstract

Two interesting “no hole” spacetime properties (being epistemically hole free (g), not being future nakedly singular) are unstable in the fine topology.