arXiv subjects

M. Ghominejad

Publications and source records attributed to M. Ghominejad.

5 recordsLinked to original sources

arXiv2024

Quantumness near a Schwarzschild black hole

The merging of quantum information science with the relativity theory presents novel opportunities for understanding the enigmas surrounding the transmission of information in relation to black holes. For this purpose, we study the quantumness near a Schwarzschild black hole in a practical model under decoherence. The scenario we consider in this paper is that a stationary particle in the flat region interacts with its surroundings while another particle experiences free fall in the vicinity of a Schwarzschild black hole's event horizon. We explore the impacts of Hawking radiation and decoherence on the system under investigation and find that these effects can limit the survival of quantum characteristics, but cannot destroy them completely. Hence, the results of this study possess the potential to yield valuable insights into the comprehension of the quantum properties of a real system operating within a curved space-time framework.

gr-qc↗

arXiv2017

Higher Dimensional Charged AdS Black Holes at Ultra-spinning Limit and Their 2d CFT Duals

By using the ultra-spinning limit as a generating solution technique, we construct a novel class of charged rotating asymptotic AdS black holes. That describes the exact D-dimnsioanl solutions of Einstein-Maxwell dilaton theory in the presence of negative cosmological constant. The obtained geometries possess some punctures, describing a noncompact horizon, but has a finite area. We then explicitly investigate the validity of the Kerr/CFT correspondence for all dimensional cases. We find a main result for the central charges associated to $[(d-1)/2]$ copies of dual $2D$ CFTs. We then argue the existence of a precise agreement between the microscopic entropy of dual CFTs and the entropy of the noncompact horizon.

hep-th↗

arXiv2017

Ultra-Spinning Gauged Supergravity Black Holes and their Kerr/CFT Correspondence

Recently a new class of asymptotically AdS ultra-spinning black holes has been constructed with a noncompact horizon of finite area [1], in which the asymptotic rotation is effectively boosted to the speed of light. We employ this technique for four-dimensional $U(1)^4$ and five-dimensional $U(1)^3$ gauged supergravity black holes. The obtained new exact black hole solutions for both cases possess a noncompact horizon; their topologies are a sphere with two punctures. We then demonstrate that the ultra-spinning limit commutes with the extremality condition as well as the near horizon limit for both black holes. We also show that the near horizon extremal geometries of the resulting ultra-spinning gauged supergravity black holes lead to the well-known result which contains an AdS$_2$ throat. We then obtain the $[(d-1)/2]$ central charges of the dual CFTs. By assuming the Cardy formula, we show that despite the noncompactness of the horizon, microscopic entropy of the dual CFT is precisely equivalent to the Bekenstein-Hawking entropy.

hep-th↗

arXiv2015

Breaking of parallelograms in presence of torsion: an equivalent alternative approach to detect gravitational waves

The equations for gravitational plane waves produced by a typical binary system as a solution of linear approximation of Einstein equations is derived. The dynamics of the corresponding gravitational field is analyzed in a 4-dimensional space-time manifold, endowed with a metric and taking into account the torsion. In this context, the geometrical reason of the existence of torsion due to the presence of gravitational waves, as an asymmetry of connection coefficients with respect of the swapping of indices's is highlighted. In a laser interferometer gravitational detector The delay time between the arrivals of the two laser beams traveling back and forth along the two arms of in presence of gravitational waves, is interpreted from this point of view. The geometrical interpretation of torsion, links this delay time to the breaking of the parallelogram formed by the trajectories of the laser beams in space-time. This delay is calculated for a typical NS-NS binary pulsar in two specific orientations with respect of the experimental device, corresponding to different polarizations of the gravitational waves. These values are related to the relative length variation of the detector's arms in presence of gravitational waves, and shown to be completely equivalent to the results obtained in the context of the standard General Relativity.

gr-qc↗

arXiv2014

On Remarks on the spin-one Duffin-Kemmer-Petiau equation in the presence of nonminimal vector interactions in (3+1) dimensions

In a very recent manuscript [arXiv:1403.6035], Castro and Oliveira have commented on our recently published paper [2]. Their main criticism is that we have used an improper nonminimal interaction term. Regarding their work, we wish to mention two points. 1. We have started the paper based on the work of Kozak et al. [3] which has successfully discussed the deuteron-nucleus scattering. 2. The second point is that we have used in our calculations \b{eta}0 and not (which preserves the current conservation). Therefore, the content of our work is correct.

hep-th↗