Fri - 08/25/23

Coherent states for generalized uncertainty relations as Tsallis probability amplitudes: new route to non-extensive thermostatistics

  • Authors: Petr Jizba, Gaetano Lambiase, Giuseppe Gaetano Luciano, Luciano Petruzziello
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Quantum Physics (quant-ph)
  • Arxiv link: https://arxiv.org/abs/2308.12368
  • Abstract We study coherent states associated to a generalized uncertainty principle (GUP). We separately analyze the cases of positive and negative deformation parameter $\beta$, showing that the ensuing probability distribution is a Tsallis distribution whose non-extensivity parameter $q$ is monotonically related to $\beta$. Moreover, for $\beta <0$ (corresponding to $q<1$), we reformulate the GUP in terms of a one-parameter class of Tsallis entropy-power based uncertainty relations, which are again saturated by the GUP coherent states. We argue that this combination of coherent states with Tsallis entropy offers a natural conceptual framework allowing to study quasi-classical regime of GUP in terms of non-extensive thermodynamics. We substantiate our claim by discussing generalization of Verlinde’s entropic force and ensuing implications in the late-inflation epoch. Corresponding dependence of the $\beta$ parameter on cosmological time is derived for the reheating epoch. The obtained $\beta$ is consistent with values predicted by both string-theory models and the naturalness principle. Further salient issues, including derivation of new $\beta$-dependent expressions for the lowest possible value of the spin and Immirzi parameter in Loop Quantum Gravity, and connection of our proposal with the Magueijo–Smolin doubly special relativity are also discussed. This article provides a more extended and comprehensive treatment of our recent letter [Phys. Rev. D 105, L121501 (2022)].

There is no new related paper today

  1. [2308.12811] - On the gravitational energy problem and the energy of photons - J. B. Formiga, João Duarte

Thu - 08/24/23

There is no new related paper today

There is no new related paper today

  1. [2308.12155] - Novel regular black holes: geometry, source and shadow - Anjan Kar, Sayan Kar (Indian Institute of Technology Kharagpur, India)

  2. [2308.12251] - Regular black holes from higher-derivative and nonlocal gravity: The smeared delta source approximation - Tibério de Paula Netto, Breno L. Giacchini, Nicolò Burzillà, Leonardo Modesto

  3. [2308.11686] - Relativistic Hydrodynamics under Rotation: Prospects & Limitations from a Holographic Perspective - Markus A. G. Amano, Casey Cartwright, Matthias Kaminski, Jackson Wu

  4. [2308.11701] - Equivariant localization for AdS/CFT - Pietro Benetti Genolini, Jerome P. Gauntlett, James Sparks

  5. [2308.11856] - Thermal quench of a dynamical QCD model in an external electric field - Sara Heshmatian, Alexander Trounev

Wed - 08/23/23

Generalized analysis of a dust collapse in effective loop quantum gravity: fate of shocks and covariance

  • Authors: Kristina Giesel, Hongguang Liu, Parampreet Singh, Stefan Andreas Weigl
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
  • Arxiv link: https://arxiv.org/abs/2308.10953
  • Abstract Based on modifications inspired from loop quantum gravity (LQG), spherically symmetric models have recently been explored to understand the resolution of classical singularities and the fate of the spacetime beyond. While such phenomenological studies have provided useful insights, questions remain on whether such models exhibit some of the desired properties such as consistent LTB conditions, covariance and compatibility with the improved dynamics of loop quantum cosmology in the cosmological and LTB sectors. We provide a systematic procedure to construct effective spherically symmetric models encoding LQG modifications as a $1+1$ field theory models encoding these properties following the analysis in our companion paper. As concrete examples of our generalized strategy we obtain and compare with different phenomenological models which have been investigated recently and demonstrate resolution of singularity by quantum geometry effects via a bounce. These include models with areal gauge fixing, a polymerized vacuum solution, polymerized junction conditions and an Oppenheimer-Snyder dust collapse model. An important insight from our approach is that the dynamical equations care about the $\det(e)$ part rather than the square root of the determinant of the spatial metric. As a result, shock solutions which have been argued to exist in some models are found to be absent even if one considers coordinate transformations.

There is no new related paper today

  1. [2308.11595] - Cosmic acceleration in Lovelock quantum gravity - M. Bousder, A.Riadsolh, M El Belkacemi, H. Ez-Zahraouy

Tue - 08/22/23

Loop quantum black hole

  • Authors: Xiangdong Zhang
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2308.10184
  • Abstract In the last decades, progress on the quantization of black holes using techniques developed in loop quantum cosmology has received increasing attention. Due to the quantum geometry effect, the resulting quantum corrected black hole is free of singularity. The quantization scheme can be roughly divided into four types, that is 1. $\mu_0$-scheme, 2. $\bar{\mu}$-scheme, 3. generalized $\mu_0$-scheme, 4. quantum collapsing model. This paper provides an introduction of the loop quantum black hole models and a summary of the progress made in this field, as well as the quantum effective dynamics and physical applications of these models.

The instability of the inner horizon of the quantum-corrected black hole

  • Authors: Li-Ming Cao, Long-Yue Li, Liang-Bi Wu, Yu-Sen Zhou
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2308.10746
  • Abstract We analyse the stability of the inner horizon of the quantum-corrected black hole which is proposed in loop quantum gravity as the exterior of the quantum Oppenheimer-Snyder and Swiss Cheese models. It is shown that the flux and energy density of a test scalar field measured by free-falling observers are both divergent near the Cauchy horizon. By considering the generalized Dray-‘t Hooft-Redmond relation which is independent of the field equation, we find that the mass inflation always happens and the scalar curvature and Kretschmann scalar are also divergent on the inner horizon. These suggest that the inner horizon is unstable and will probably turn into a null singularity. The results support the strong cosmic censorship hypothesis. However, this also implies that the quantum corrected model may not be the definitive endpoint as a regular black hole. Besides, it further proposes that any possible observable astronomical phenomenon which depends on the existence of the inner horizon of the black hole is not reliable.

There is no new related paper today

  1. [2308.10498] - Raychaudhuri equation and Bouncing cosmology - Madhukrishna Chakraborty, Subenoy Chakraborty

  2. [2308.10890] - Dust collapse in asymptotic safety: a path to regular black holes - Alfio Bonanno, Daniele Malafarina, Antonio Panassiti

  3. [2308.09748] - de Sitter space is sometimes not empty - Vijay Balasubramanian, Yasunori Nomura, Tomonori Ugajin

  4. [2308.09758] - Entanglement structure in quantum many-body systems, field theories, and holography - Takato Mori

Mon - 08/21/23

The Quantum Waves of Minkowski Spacetime And The Minimal Acceleration From Precanonical Quantum Gravity

  • Authors: I.V. Kanatchikov
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2308.08738
  • Abstract We construct the simplest solutions of the previously obtained precanonical Schr"odinger equation for quantum gravity, which correspond to the plane waves on the spin connection bundle and reproduce the Minkowski spacetime on average. Quantum fluctuations lead to the emergence of the minimal acceleration $a_0$ related to the range of the Yukawa modes in the fibers of the spin connection bundle. This minimal acceleration is proportional to the square root of the cosmological constant $\Lambda$ generated by the operator re-ordering in the precanonical Schr"odinger equation. Thus the mysterious connection between the minimal acceleration $a_0$ in the dynamics of galaxies as described by Milgrom’s MOND and the cosmological constant emerges as an elementary effect of precanonical quantum gravity. We also argue that the observable values of $a_0$ and $\Lambda$ can be obtained when the scale of the parameter $\varkappa$ introduced by precanonical quantization is subnuclear, in agreement with the previously established connection between the scale of $\varkappa$ and the mass gap in quantum SU(2) Yang-Mills theory.

There is no new related paper today

  1. [2308.09246] - Holomorphic General Coordinate Invariant Modified Measure Gravitational Theory - Eduardo Guendelman

  2. [2308.09555] - Connections between Weyl geometry, quantum potential and quantum entanglement - Shi-Dong Liang, Wenjing Huang

  3. [2308.08600] - Rényi mutual information in quantum field theory, tensor networks, and gravity - Jonah Kudler-Flam, Laimei Nie, Akash Vijay

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