Fri - 10/13/23

There is no new related paper today

There is no new related paper today

  1. [2310.07823] - Universal IR Holography, Scalar Fluctuations and Glueball spectra - Andrés Anabalón, Horatiu Nastase

  2. [2310.07860] - Generalized black branes in AdS/CMT and holographic superconductors - Roldao da Rocha

Thu - 10/12/23

Effective Hamiltonian of the k=+1 FRW model from the K-Quantization method in LQC

  • Authors: Akram Hasseine
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2310.07012
  • Abstract In the effective theory of loop quantum cosmology LQC, the influence of the holonomy correction (with $\overline{\mu}$-scheme) on the homogeneous and the inhomogeneous cosmological models have been extensively studied in the case of flat space. In this paper,using the K-Quantization method and the $\overline{\mu}$-scheme,in the same framework of LQC,we construct the Hamiltonian constraint operator of the closed FRW model (k=+1), we show that the effective semi-classical limit gives the same holonomy correction expression that was already used in the case of a flat space. We also derive the modified Friedman equation. The numerical investigation is performed to plot the effective evolution of the massless scalar field in term of the volume,which indicate a minimum volume at the bounce and also a suitable infrared behavior.The condition that we apply to constrain the value of $\overline{\mu}$ in the semi-classical limit is consistent with the numerical results.

There is no new related paper today

  1. [2310.07228] - Euclidean methods and phase transitions for the strongest deformations compatible with Schwarzschild asymptotics - Ioannis Soranidis

  2. [2310.06895] - Global anomalies & bordism of non-supersymmetric strings - Ivano Basile, Arun Debray, Matilda Delgado, Miguel Montero

  3. [2310.07213] - Species Scale in Diverse Dimensions - Damian van de Heisteeg, Cumrun Vafa, Max Wiesner, David H. Wu

  4. [2310.07499] - Functional renormalization group for signal detection and stochastic ergodicity breaking - Harold Erbin, Riccardo Finotello, Bio Wahabou Kpera, Vincent Lahoche, Dine Ousmane Samary

  5. [2310.07708] - On the Species Scale, Modular Invariance and the Gravitational EFT expansion - Alberto Castellano, Alvaro Herráez, Luis E. Ibáñez

Wed - 10/11/23

There is no new related paper today

There is no new related paper today

  1. [2310.06018] - Gravitational probe of quantum spacetime - Nikola Herceg, Tajron Jurić, Andjelo Samsarov, Ivica Smolić, Kumar S. Gupta

  2. [2310.06798] - Emergent modified gravity: Covariance regained - Martin Bojowald, Erick I. Duque

  3. [2310.06012] - Holographic description of Narain CFTs and their code-based ensembles - Ofer Aharony, Anatoly Dymarsky, Alfred D. Shapere

  4. [2310.06019] - Waiting for Inflation: A New Initial State for the Universe - Brandon Melcher, Arnab Pradhan, Scott Watson

  5. [2310.06048] - Regularized Weyl double copy - Gokhan Alkac, Mehmet Kemal Gumus, Oguzhan Kasikci, Mehmet Ali Olpak, Mustafa Tek

Tue - 10/10/23

Shadow, quasinormal modes, greybody bounds, and Hawking sparsity of Loop Quantum Gravity motivated non-rotating black hole

  • Authors: Sohan Kumar Jha
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2310.04759
  • Abstract We consider Loop Quantum Gravity(LQG) motivated $4D$ polymerized black hole and study shadow, quasinormal modes, and Hawking radiation. We obtain analytical expressions of photonsphere radius and shadow radius and study their qualitative and quantitative nature of variation with respect to the LQG parameter $\alpha$. We also show shadows of the black hole for various values of $\alpha$. Our study reveals that both radii increase with an increase in the parameter value. We, then, study quasinormal modes for scalar and electromagnetic perturbations using the $6th$ order WKB method. Our study reveals that the LQG parameter impacts quasinormal modes. We observe that the oscillation of gravitational wave(GW) and decay rate decrease as $\alpha$ increases. At the same time, the error associated with the $6th$ order WKB method increases with an increase in $\alpha$. The ringdown waveform for electromagnetic and scalar perturbations is shown. We also study greybody bounds, power spectrum, and sparsity of Hawking radiation. Greybody bounds for electromagnetic perturbations do not depend on $\alpha$. For scalar perturbation, greybody bounds increase as the LQG parameter increases, but the variation with $\alpha$ is very small. The peak of the power spectrum as well as total power emitted decrease as we increase the value of $\alpha$. Also, the sparsity of Hawking radiation gets significantly impacted by quantum correction. Finally, we obtain the area spectrum of the black hole. It is found to be significantly different than that for the Schwarzschild black hole.

Melonic Radiative Correction in Four-Dimensional Spinfoam Model with Cosmological Constant

  • Authors: Muxin Han, Qiaoyin Pan
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2310.04537
  • Abstract Infrared divergence is a common feature of spinfoam models with a vanishing cosmological constant but is expected to disappear in presence of a non-vanishing cosmological constant. In this paper, we investigate the spinfoam amplitude with cosmological constant introduced in arXiv:2109.00034 on the melon graph, which is known as the melonic radiative correction. The amplitude closely relates to the state-integral model of complex Chern-Simons theory. We prove that the melonic radiative correction is finite in presence of a non-vanishing cosmological constant, in contrast to the infrared divergence of spinfoam models with a vanishing cosmological constant. In addition, we also analyze the scaling behavior of the radiative correction in the limit of small cosmological constant.

  1. [2310.04650] - Gravity-induced entanglement between two massive microscopic particles in curved spacetime: II.Friedmann- Lemaître-Robertson-Walker universe - Chi Zhang, Fu-Wen Shu

  2. [2310.04488] - Emergence of Species Scale Black Hole Horizons - José Calderón-Infante, Matilda Delgado, Angel M. Uranga

Mon - 10/09/23

Quantum Features of the Cosmological Horizon

  • Authors: Eleanor Harris
  • Subjects: High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2310.04193
  • Abstract This thesis explores the thermodynamics of the cosmological horizon, aiming to make progress towards a better understanding of the microscopic nature of its entropy. We utilise the constrained nature of low-dimensional gravity to do so and investigate timelike boundaries in these theories, with an emphasis on the stretched horizon holographic picture. Given the success of AdS/CFT, one might try to embed de Sitter inside anti-de Sitter and describe the expanding region from the boundary. In two dimensions, such geometries exist and, by studying them in the presence of a timelike boundary, we find thermally stable solutions. We thus propose a dual matrix model that should describe this geometry, including the expanding region. One way to test this duality would be to compare bulk and boundary correlators. However, for de Sitter this poses a puzzle: in the saddle point approximation two-point functions are given by a sum over geodesics. Such correlation functions exist for any two arbitrary points in de Sitter, but geodesics do not. This is resolved by including complex saddles that appear upon Wick rotating from the sphere. Additionally, one can use the relationship between three-dimensional gravity and Chern-Simons theory to explore thermodynamic contributions to the de Sitter horizon. The Euclidean gravitational path integral provides the exact, all-loop quantum corrected de Sitter entropy. To understand the microscopic origin of this entropy, one hopes to find an analogous Lorentzian calculation that produces this result. This takes the form of an edge-mode theory living close to the cosmological horizon with a complexified gauge group, leading to an unbounded spectrum. To make progress, we study a comparable Abelian theory that leads to an entropy with an entanglement character. Finally, we summarise some new results on edge-mode theories arising from general boundary conditions.

There is no new related paper today

  1. [2310.04319] - Towards a quantum field theory description of nonlocal spacetime defects - Christopher D. Carone, Noah L. Donald

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