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Vahid Reza Shajiee

Publications and source records attributed to Vahid Reza Shajiee.

6 recordsLinked to original sources
arXiv2025

Counting Black Hole Microstates at Future Null Infinity

We propose a black hole microstate counting method based on the canonical quantization of the asymptotic symmetries of a two-dimensional dilaton-gravity system at future null infinity. This dilaton-gravity is obtained from the s-wave reduction of an $N$-dimensional Einstein gravity over a generic asymptotically flat black hole solution. We show that a Cardy-type formula leads to the Bekenstein-Hawking entropy. In this scenario, the quantized bulk degrees of freedom act as a source for the dual field theory operators living at future null infinity that are soft gravitons of the higher dimensional system, up to some gauge fixing.

hep-th↗
arXiv2023

Dominant Spacetime in Three Dimensional de Sitter Gravity

In three dimensions, Kerr-de Sitter spacetime as a solution of Einstein gravity with positive cosmological constant has a single cosmological horizon. The flat-space limit (zero cosmological constant limit) of this spacetime is well-defined and yields the flat-space cosmological solution which is a significant spacetime in the context of flat-space holography. In this paper, we calculate the free energy of this spacetime and compare it with the free energy of the three-dimensional de Sitter spacetime. We investigate which one of these two spacetimes will dominate in the semi-classical approximation for estimating the partition function. It is shown that for the same temperature of cosmological horizon of two spacetimes this is the de Sitter spacetime which is always dominant. Hence, contrary to asymptotically flat and asymptotically AdS spacetimes, there is no phase transition in three dimensional de Sitter gravity.

hep-th↗
arXiv2020

The Schwarzschild/CFT Correspondence: Weyl Rescaled Case

In this work, the CFT dual of the Schwarzschild black hole is investigated. A Weyl rescaling factor is presented, so that the Weyl rescaled Schwarzschild metric, after a coordinate transformation, has an $AdS_{2} \times S^{2}$ geometry at vicinity of its origin. Since the near origin spacetime admits an $AdS_{2}$ factor, it is dealt with a 2D effective gravity which is dimensionally reduced from the near origin solution. It is exhibited that the dual CFT has a central charge $c=96 M^3$ which is an asymptotic conserved charge of the effective solution. Finally, the microscopic entropy of Schwarzschild black hole is achieved by using Cardy formula. It is revealed that the microscopic entropy exactly reproduces the Bekenstein-Hawking entropy of the Schwarzschild black hole.

hep-th↗
arXiv2019

Electroweak Phase Transition, Gravitational Waves and Dark Matter in Two Scalar Singlet Extension of The Standard Model

In this paper, the electroweak phase transition, the gravitational waves and the dark matter issues are investigated in two scalar singlet extension of the standard model. The detectability of the gravitational wave signals are discussed by comparing the results with the sensitivity curves of $\mathbf{eLISA}$, $\mathbf{ALIA}$, $\mathbf{DECIGO}$ and $\mathbf{BBO}$ detectors. It is shown that the results support the recent reports on the dark matter relic density by $\mathbf{Planck}$ $\mathbf{2018}$ collaboration and the direct detection experiment by $\mathbf{XENON1T}$ $\mathbf{2018}$ collaboration.

hep-ph↗
arXiv2017

Quantum Tunneling from the Charged Non-Rotating BTZ Black Hole with GUP

In the present paper, the quantum corrections to the temperature, entropy and specific heat capacity of the charged non-rotating BTZ black hole are studied by generalized uncertainty principle in tunneling formalism. It is shown that quantum corrected entropy would be of the form of predicted entropy in quantum gravity theories like string theory and loop quantum gravity.

hep-th↗