arXiv subjects

Mahdi Atashi

Publications and source records attributed to Mahdi Atashi.

5 recordsLinked to original sources

arXiv2022

Quantum Thermodynamics of a Quantum Sized AdS Black Hole

In this paper, we investigate the effects of non-perturbative quantum gravitational corrections on a quantum sized AdS black hole. It will be observed that these non-perturbative quantum gravitational corrections modify the stability of this black hole. We will use the non-equilibrium quantum thermodynamics to investigate the evaporation of this black hole between two states. We will analyze the effects of non-perturbative quantum gravitational corrections on this non-equilibrium quantum thermodynamics. We will explicitly obtain the quantum work distribution for this black hole, as it evaporates between two states. It will be observed that this quantum work distribution is modified due to non-perturbative quantum gravitational corrections.

gr-qc↗

arXiv2022

Anomalous dimension and quasinormal modes of flavor branes

We study scalar quasinormal modes in a D3/D7 system holographically dual to a quantum field theory with chiral symmetry breaking at finite temperature. From the bottom-up approach, we consider a nontrivial dilaton profile which is responsible for the anomalous dimension of the quark condensate. It depends on a new parameter$ q$ in the model. By varying this parameter, we study the behavior of the massive and massless scalar quasinormal modes. The numerical method that we use is the spectral method, and we find that there is no pure imaginary mode for the massless case but it appears by increasing the parameter $q$. It is known that this mode becomes tachyonic for massive cases. Then we turn on a pseudoscalar field and using a simple ansatz study its effect on the quasinormal modes of the scalar field. By varying the parameter of the nontrivial dilaton profile in the model, we qualitatively study quasinormal modes in walking theories.

hep-th↗

arXiv2019

Spiraling String in Gauss-Bonnet Geometry

In this paper, we consider a spiraling string falling in the bulk with Gauss$-$Bonnet geometry that is holographically dual to a heavy particle rotating through a hot plasma at finite coupling. One finds such interesting simple problem provides a novel perspective on different channels of the energy loss in the corresponding strongly coupled theory. Depends on the sign of the coupling, one observes that the influence of finite coupling on total energy loss and contribution of drag force and radiation channels appears as a shift on curves with respect to the plasma with infinite coupling. Also we found that crossover between regime in which drag force contribution is predominant to regime in which energy loss is due to radiation, does not depend on the Gauss$-$Bonnet coupling.

hep-th↗

arXiv2017

Linearized Holographic Isotropization at Finite Coupling

We study holographic isotropization of an anisotropic homogeneous non-Abelian strongly coupled plasma in the presence of Gauss-Bonnet corrections. It was verified before that one can linearize Einstein's equations around the final black hole background and simplify the complicated setup. Using this approach, we study the expectation value of the boundary stress tensor. Although we consider small values of the Gauss-Bonnet coupling constant, it is found that finite coupling leads to significant increasing of the thermalization time. By including higher order corrections in linearization, we extend the results to study the effect of the Gauss-Bonnet coupling on the entropy production on the event horizon.

hep-th↗

arXiv2016

Holographic energy loss in non-relativistic backgrounds

In this paper, we study some aspects of energy loss in non-relativistic theories from holography. We analyze the energy lost by a rotating heavy point particle along a circle of radius $l$ with angular velocity $ω$ in theories with general dynamical exponent $z$ and hyperscaling violation exponent $θ$. It is shown that this problem provides a novel perspective on the energy loss in such theories. A general computation at zero and finite temperature is done and it is shown that how the total energy loss rate depends non-trivially on two characteristic exponents $(z,θ)$. We find that at zero temperature there is a special radius $l_c$ where the energy loss is independent of different values of $(θ,z)$. Also at zero temperature, there is a crossover between a regime in which the energy loss is dominated by the linear drag force and by the radiation because of the acceleration of the rotating particle. We find that the energy loss of the particle decreases by increasing $θ$ and $z$. We note that, unlike in the zero temperature, there is no special radius $l_c$ at finite temperature case.

hep-th↗