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Related papers: Old Ideas for New Physicists:1

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A common approach to evaluate entropy in quantum systems is to solve a master-Bloch equation to determine density matrix and substitute it in entropy definition. However, this method has been recently understood to lack many energy…

High Energy Physics - Theory · Physics 2016-05-17 Mohammad H Ansari

There is much recent development towards interferometric measurements of holographic quantum uncertainties in an emergent background space-time. Despite increasing promise for the target detection regime of Planckian strain power spectral…

General Relativity and Quantum Cosmology · Physics 2025-05-27 Ohkyung Kwon

From first principles, I present a concrete realization of Carlip's idea on the black hole entropy from the conformal field theory on the horizon in any dimension. New formulation is free of inconsistencies encountered in Carlip's. By…

High Energy Physics - Theory · Physics 2009-01-30 Mu-in Park

This paper presents the first numerical study of black hole thermodynamics in Causal Set Theory, focusing on the entropy of a Schwarzschild black hole as embodied in the distribution of proposed horizon molecules. To simulate causal sets we…

General Relativity and Quantum Cosmology · Physics 2024-05-02 Vid Homšak , Stefano Veroni

We have constructed a spherically symmetric structure model in a cosmological background filled with perfect fluid with non-vanishing pressure as an exact solution of Einstein equations using the Lema\^{i}tre solution. To study its local…

General Relativity and Quantum Cosmology · Physics 2015-10-07 Rahim Moradi , Javad T. Firouzjaee , Reza Mansouri

We argue that the Ising model CFT can be used to obtain some clear insights into 3D (quantum) gravity with matter. We review arguments for the existence of its holographic description, and concentrate on the time dependence of perturbations…

High Energy Physics - Theory · Physics 2025-05-13 Romuald A. Janik

Astrophysical observations provide a picture of the universe as a 4-dim homogeneous and isotropic flat space-time dominated by an unknown form of dark energy. To achieve such a cosmology one has to consider in the early universe an…

Astrophysics · Physics 2009-11-10 F. Canfora , A. Troisi

We present a general framework for analyzing spatially inhomogeneous cosmological dynamics. It employs Hubble-normalized scale-invariant variables which are defined within the orthonormal frame formalism, and leads to the formulation of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Claes Uggla , Henk van Elst , John Wainwright , George F R Ellis

The hypothesis of low entropy in the initial state of the universe usually explains the observed entropy increase is in only one time direction: the thermodynamic arrow of time. The Hamiltonian formalism is commonly used in the context of…

General Relativity and Quantum Cosmology · Physics 2024-08-27 Jackie C. H. Liu

Entropy is a fundamental concept from Thermodynamics and it can be used to study models on context of Creation Cold Dark Matter (CCDM). From conditions on the first ($\dot{S}\geq0$)\footnote{Throughout the present work we will use dots to…

General Relativity and Quantum Cosmology · Physics 2020-12-02 R. Valentim , J. F. Jesus

In this paper, we demonstrate that the first law of holographic pseudo-entropy, which is a non-Hermitian generalization of entanglement entropy in a two-dimensional conformal field theory (CFT), is equivalent to the perturbative Einstein…

High Energy Physics - Theory · Physics 2025-12-01 Kosei Fujiki , Michitaka Kohara , Kotaro Shinmyo , Yu-ki Suzuki , Tadashi Takayanagi

We identify a horizon-skimming limit under which wave equations around large classes of black holes allow a determination of their low-lying (quasi-)degenerate normal modes. Building on our recent work, we use these ``quantum horizon"…

High Energy Physics - Theory · Physics 2024-10-02 Chethan Krishnan , Pradipta S. Pathak

The holographic state of matter exists in the quantum gravitational regime, with black holes as the example. In this essay, we provide a microscopic derivation to the holographic thermodynamics and further discuss its implications for…

General Relativity and Quantum Cosmology · Physics 2021-04-01 Yong Xiao

Quantum theory, general relativity, the standard model of particle physics, and the $\Lambda$CDM model of cosmology have all been spectacularly successful within their respective regimes of applicability, but many central problems remain…

General Physics · Physics 2026-05-26 Roland E. Allen

As is well known, black hole entropy is proportional to the area of the horizon suggesting a holographic principle wherein all degrees of freedom contributing to the entropy reside on the surface. In this note, we point out that large scale…

General Physics · Physics 2013-12-19 C. Sivaram , Kenath Arun

In the present work the approach - density matrix deformation - earlier developed by the author to study a quantum theory of the Early Universe (Planck's scales) is applied to study a quantum theory of black holes. On this basis the author…

General Relativity and Quantum Cosmology · Physics 2015-06-25 A. E. Shalyt-Margolin

The approach of 't Hooft to the puzzles of black hole evaporation can be applied to a simpler system with analogous features. The system is $1+1$ dimensional electrodynamics in a linear dilaton background. Analogues of black holes, Hawking…

High Energy Physics - Theory · Physics 2009-10-07 Amanda Peet , Leonard Susskind , Larus Thorlacius

In this talk we entertain the possibility that the synthesis of general covariance and quantum mechanics requires an extension of the basic kinematical setup of quantum mechanics. According to the holographic principle, regions of spacetime…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Vijay Balasubramanian , Jan de Boer , Djordje Minic

We study the thermodynamical properties of black holes when described as gases of indistinguishable punctures with a chemical potential. In this picture, which arises from loop quantum gravity, the black hole microstates are defined by…

General Relativity and Quantum Cosmology · Physics 2015-04-08 Olivier Asin , Jibril Ben Achour , Marc Geiller , Karim Noui , Alejandro Perez

We analyze cosmology assuming unitary quantum mechanics, using a tripartite partition into system, observer and environment degrees of freedom. This generalizes the second law of thermodynamics to "The system's entropy can't decrease unless…

High Energy Physics - Theory · Physics 2013-05-30 Max Tegmark