Weekly Papers on Quantum Foundations (3)

We reconstruct finite-dimensional quantum theory from categorical principles. That is, we provide properties ensuring that a given physical theory described by a dagger compact category in which one may `discard’ objects is equivalent to a generalised finite-dimensional quantum theory over a suitable ring $S$. The principles used resemble those due to Chiribella, D’Ariano and Perinotti. Unlike previous reconstructions, our axioms and proof are fully categorical in nature, in particular not requiring tomography assumptions. Specialising the result to probabilistic theories we obtain either traditional quantum theory with $S$ being the complex numbers, or that over real Hilbert spaces with $S$ being the reals.

Authors: P. B. Lerner

These are author’s recollections of informal discussions on foundations of quantum mechanics, which happened in his presence in 1970-80s

Authors: James Q. Quach

We show that the weak equivalence principle (WEP) is violated for a quantum particle in a gravitational wave (GW) background. In a freely-falling frame, the expected trajectory of a quantum particle is independent of the GW, but its probability distribution is not. By monitoring the position of the particle, extra mass information can be extracted due to the GW, in violation of the WEP. We then ask, can the probability distribution of a quantum particle be used as a GW detector? In principle yes, but in practice unlikely, due to the unfeasibly high accuracy of particle detection required.

Authors: Diego Pavon

By examining whether black holes fulfill the theorem of equipartition of energy we find that the notion of degrees of freedom, previously introduced for cosmic horizons, is meaningful in the case of Schwarzschild and Kerr black holes. However, for Reissner-N\”{o}rdstrom and Kerr-Newman black holes this notion fails.

上午9:26 | gr-qc updates on arXiv.org

Authors: Luca BuoninfanteGaetano LambiaseGiuseppe Gaetano LucianoLuciano Petruzziello

We study quantum corrections at the horizon scale of a black hole induced by a Generalized Uncertainty Principle (GUP) with a quadratic term in the momentum. The interplay between quantum mechanics and gravity manifests itself into a non–zero uncertainty in the location of the black hole radius, which turns out to be larger than the usual Schwarzschild radius. We interpret such an effect as a correction which makes the horizon disappear, as it happens in other models of quantum black holes already considered in literature. We name this kind of horizonless compact objects $GUP stars$. We also investigate some phenomenological aspects in the astrophysical context of binary systems and gravitational wave emission by discussing Love numbers, quasi–normal modes and echoes, and studying their behavior as functions of the GUP deformation parameter. Finally, we preliminarily explore the possibility to constrain such a parameter with future astrophysical experiments.

2020年1月17日 星期五 下午1:35 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Chen, Eddy Keming (2020) Time’s Arrow and De Se Probabilities. [Preprint]
2020年1月16日 星期四 下午6:22 | Ashkan Shekaari, Mahmoud Jafari | quant-ph updates on arXiv.org

We have developed a theoretical formalism to introduce temperature as a parameter into the framework of non-relativistic quantum mechanics using the laws of classical thermodynamics and the canonical ensemble scheme of statistical mechanics. A self-consistent Hamiltonian has then been constructed for a given quantum many-body system which includes the effect of temperature in the form of correction terms added to the corresponding zero-temperature Hamiltonian of the system. Investigating some quantum mechanical systems with exact zero-temperature solutions including the particle-in-a-box model, the free particle, and the harmonic oscillator within our finite-temperature approach up to the first order of self-consistency has led to temperature-dependent Hamiltonians describing these systems above absolute zero without encountering any physically unacceptable brand of behavior for their wave functions and energy spectra. Results firmly support the view that a quantum mechanical system at a finite temperature behaves as if it is in a zero-temperature excited state.

2020年1月16日 星期四 下午6:22 | physics.hist-ph updates on arXiv.org

Authors: Vladimir A. Petrov

Quite a long time ago several authors (see,e.g., \cite{Der}, \cite{Pe} ) mentioned that among pioneers of the quark idea we should take into consideration one more (in addition to M. Gell-Mann and G. Zweig) author, Andr\'{e} Petermann (1922 – 2011). Below we place the English translation of his little known work, originally published in French. We draw attention of the readers to the closesness of the dates: M. Gell-Mann’s paper in Phys.Letters was received 4 January 1964, the CERN preprint by G. Zweig is dated by 17 January 1964 while Petermann’s paper in Nucl.Phys. was received 30 December 1963.

2020年1月16日 星期四 下午6:22 | gr-qc updates on arXiv.org

Authors: Yigit YargicLaura SbernaAchim Kempf

We consider the possibility that, in the semiclassical Einstein equation for cosmological spacetimes, gravity is sourced by the amount of stress-energy that is above that of the instantaneous ground state. For this possibility to be consistent, the Bianchi identities must continue to hold. This is nontrivial because it means that the ground state expectation value of the stress-energy tensor must be covariantly conserved in spite of the fact that the ground state is generally a different state at different times. We prove that this consistency condition does hold. As a consequence, we find that the vacuum stress-energy which is above the instantaneous ground state does not renormalize the cosmological constant, as long as the instantaneous ground states and the instantaneous adiabatic vacua exist.

2020年1月16日 星期四 下午6:22 | gr-qc updates on arXiv.org

Authors: Ulf-G. Meißner

Precision predictions combined with precise measurements are a major tool in sharpening our understanding of the fundamental laws underlying microscopic as well as macroscopic systems. Here, I present a few remarkable examples covering the fields of nuclear, particle and astrophysics.

Authors: Tommaso De Lorenzo

This thesis is entirely devoted to black hole physics as a natural arena to study quantum gravity related questions. The five main Chapters present the results already published in arXiv:1512.04566 [gr-qc], arXiv:1604.07222 [gr-qc], arXiv:1707.00479 [gr-qc], arXiv:1807.02041 [gr-qc], arXiv:1811.03667 [gr-qc]. A main introductory Section, together with the Sections introducing each of the two parts of the manuscript compose the \emph{fil rouge} of the thesis, and are not published elsewhere. They contain reviews (together with my personal view) on the information paradox (Part 1) and the thermodynamics of spacetime (Part 2).

2020年1月16日 星期四 下午6:22 | gr-qc updates on arXiv.org

Authors: Ben FreivogelThomas GasenzerArthur HebeckerSascha Leonhardt

We conjecture that, in a renormalizable effective quantum field theory where the heaviest stable particle has mass $m$, there are no bound states with radius below $1/m$ (Bound State Conjecture). We are motivated by the (scalar) Weak Gravity Conjecture, which can be read as a statement forbidding certain bound states. As we discuss, versions for uncharged particles and their generalizations have shortcomings. This leads us to the suggestion that one should only constrain rather than exclude bound objects. In the gravitational case, the resulting conjecture takes the sharp form of forbidding the adiabatic construction of black holes smaller than $1/m$. But this minimal bound-state radius remains non-trivial as $M_\text{P}\to \infty$, leading us to suspect a feature of QFT rather than a quantum gravity constraint. We find support in a number of examples which we analyze at a parametric level.

2020年1月15日 星期三 下午6:31 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Le Bihan, Baptiste (2020) String Theory, Loop Quantum Gravity and Eternalism. [Preprint]
2020年1月14日 星期二 下午3:06 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Hetzroni, Guy (2020) Relativity and Equivalence in Hilbert Space: A Principle-Theory Approach to the Aharonov-Bohm Effect. Foundations of Physics. ISSN 1572-9516
2020年1月14日 星期二 下午2:52 | Philsci-Archive: No conditions. Results ordered -Date Deposited.
Dorato, Mauro (2020) Bohr meets Rovelli:a dispositionalist account of the quantum state. [Preprint]
2020年1月14日 星期二 上午8:00 | Latest Results for Synthese

Abstract

Of all the demands that mathematics imposes on its practitioners, one of the most fundamental is that proofs ought to be correct. It has been common since the turn of the twentieth century to take correctness to be underwritten by the existence of formal derivations in a suitable axiomatic foundation, but then it is hard to see how this normative standard can be met, given the differences between informal proofs and formal derivations, and given the inherent fragility and complexity of the latter. This essay describes some of the ways that mathematical practice makes it possible to reliably and robustly meet the formal standard, preserving the standard normative account while doing justice to epistemically important features of informal mathematical justification.

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