Fri - 11/12/21

There is no new related paper today

There is no new related paper today

  1. [2111.05878] - Natural evidence for fuzzy sphere noncommutative geometry: super-Chandrasekhar white dwarfs - Surajit Kalita, T. R. Govindarajan, Banibrata Mukhopadhyay

  2. [2111.05879] - Insights on Entanglement Entropy in $1+1$ Dimensional Causal Sets - Théo Keseman, Hans J. Muneesamy, Yasaman K. Yazdi

  3. [2111.05984] - On generalization of 2d gravity with the simplest non-invariant states - Damir Sadekov

  4. [2111.06298] - The Entanglement Wedge of Unknown Couplings - Ahmed Almheiri, Henry W. Lin

Thu - 11/11/21

Thermodynamics in new model of loop quantum cosmology

  • Authors: Xiangdong Zhang
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2111.05660
  • Abstract The thermodynamic properties of loop quantum cosmology (LQC) without considering the Lorentz term were established in \cite{Zhu09}. In this paper, we extend this result to the recent proposed new model of LQC with the Lorentz term. We investigate the thermodynamics of LQC on the apparent horizon of the Friedmann-Lematre-Robertson-Walker universe. The result shows that the effective density and effective pressure in the modified Friedmann equation of LQC not only determines the evolution of the universe but can also serve as the thermodynamic quantities. Moreover, with the help of the Misner-Sharp energy, the first law of thermodynamics of the LQC is still valid as expected. This in turn endows precise physical meaning to the effective matter density $\rho_{eff}$ and the effective pressure $P_{eff}$.

There is no new related paper today

  1. [2111.05355] - Holevo Information and Ensemble Theory of Gravity - Xiao-Liang Qi, Zhou Shangnan, Zhenbin Yang

Wed - 11/10/21

There is no new related paper today

There is no new related paper today

  1. [2111.05018] - Black Hole Remnants from Dynamical Dimensional Reduction? - Frank Saueressig, Amir Khosravi

  2. [2111.05151] - The averaged null energy condition on holographic evaporating black holes - Akihiro Ishibashi, Kengo Maeda

  3. [2111.05295] - Contrasting the fuzzball and wormhole paradigms for black holes - Bin Guo, Marcel R. R. Hughes, Samir D. Mathur, Madhur Mehta

Tue - 11/09/21

There is no new related paper today

There is no new related paper today

  1. [2111.04291] - Non-local $R^2$-like inflation, Gravitational Waves and Non-Gaussianities - K. Sravan Kumar

  2. [2111.04405] - Path Integral Complexity and Kasner singularities - Pawel Caputa, Diptarka Das, Sumit R. Das

  3. [2111.04696] - Asymptotic freedom and safety in quantum gravity - Saswato Sen, Christof Wetterich, Masatoshi Yamada

Fri - 11/05/21

There is no new related paper today

There is no new related paper today

  1. [2111.02894] - Bouncing cosmology in extended gravity and its reconstruction as dark energy model - A.S. Agrawal, Francisco Tello-Ortiz, B.Mishra, S.K. Tripathy

  2. [2111.02858] - A ribbon graph derivation of the algebra of functional renormalization for random multi-matrices with multi-trace interactions - Carlos I. Perez-Sanchez

Thu - 11/04/21

Polymer Quantization of the Isotropic Universe: comparison with the Bounce of Loop Quantum Cosmology

  • Authors: Gabriele Barca, Eleonora Giovannetti, Federico Mandini, Giovanni Montani
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2111.02129
  • Abstract We implement Polymer Quantum Mechanics on the Hamiltonian formulation of the isotropic Universe in both the representations of the standard Ashtekar-Barbero-Immirzi connection and of a new generalized coordinate conjugate to the Universe volume. The resulting dynamics is a bouncing cosmology; when quantizing the volume-like variable the Big Bounce is an intrinsic cut-off on the cosmological dynamics, while when using the standard connection the Bounce density results to be dependent on the initial conditions of the prepared wave packet. Then we compare the nature of the resulting Bounce with what emerges in Loop Quantum Cosmology, where the dependence of the critical density on the initial conditions is present when the minimum area eigenvalue is implemented in a comoving representation instead of the physical one. We conclude that, if one hand the preferable scenario should be a Big Bounce whose density depends on initial conditions in view of the privileged SU(2) character that the Ashtekar-Barbero-Immirzi connection possesses in the full Loop Quantum Gravity, on the other hand the equivalence demonstrated in the context of polymer cosmology can be a hint in favour of the viability of the improved scheme of Loop Quantum Cosmology even though it is not expressed through the privileged set of variables.

There is no new related paper today

  1. [2111.02137] - On a Quantum Weyl Curvature Hypothesis - Claus Kiefer

Wed - 11/03/21

There is no new related paper today

There is no new related paper today

  1. [2111.01278] - Baryon Asymmetry and Minimum Length - Saurya Das, Mitja Fridman, Gaetano Lambiase, Elias C. Vagenas

  2. [2111.01139] - Non-Invertible Duality Defects in 3+1 Dimensions - Yichul Choi, Clay Cordova, Po-Shen Hsin, Ho Tat Lam, Shu-Heng Shao

Tue - 11/02/21

There is no new related paper today

There is no new related paper today

  1. [2111.00015] - Finiteness and the Swampland - Yuta Hamada, Miguel Montero, Cumrun Vafa, Irene Valenzuela

Mon - 11/01/21

Does loop quantum $μ_o$ scheme permit a black hole formation?

  • Authors: Bao-Fei Li, Parampreet Singh
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2110.15373
  • Abstract We explore the way different loop quantization prescriptions affect the formation of trapped surfaces in the gravitational collapse of a homogeneous dust cloud, with a particular emphasis on the so called $\mu_o$ scheme in which loop quantum cosmology was initially formulated. Its undesirable features in cosmological models led to the so-called improved dynamics or the $\bar \mu$ scheme. While the jury is still out on the right scheme for black hole spacetimes, we show that as far as the black hole formation is concerned the $\mu_o$ scheme has another, so far unknown, serious problem. We find that in the $\mu_o$ scheme no trapped surfaces would form for a non-singular collapse of a homogeneous dust cloud in the marginally bound case unless the minimum non-zero area of the loops over which holonomies are computed or the Barbero-Immirzi parameter decreases almost four times from its standard value. It turns out that the trapped surfaces in the $\mu_o$ scheme for the marginally bound case are also forbidden for any arbitrary matter content as long as the collapsing interior is isometric to a spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime. We find that in contrast to the situation in the $\mu_o$ scheme, black holes can form in the $\bar \mu$ scheme, and also other lattice refinements with a mass gap determined by quantum geometry.

There is no new related paper today

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