arXiv subjects

Shad Ali

Publications and source records attributed to Shad Ali.

6 recordsLinked to original sources

arXiv2026

A model for the emission of SGRBs-GW from binary mergers

This report is divided into three main parts: 1. The first two chapters discuss the emission of Short GRB (SGRB) from binary mergers surrounded by a strong magnetic field. By introducing our model, we investigated the physics of the emission of SGRBs from rotating and charged rotating BHs. A rapidly spinning, strongly magnetized neutron star (millisecond magnetar) is the primary source of strong magnetic fields ranging from $10^{13}~\rm to ~ 10^{16} G$. The decay of the magnetic field could power electromagnetic radiation, especially X-rays and gamma rays from NSs or NS-BH mergers as their primary sources. Considering the merger of compact bodies (NS-NS or NS-BH or BH-BH), we can obtain interesting results. 2. In the next two chapters, we reviewed the BH interiors to understand the nature of black hole interior information and evaporation from its initial to final phases via entropy variation. The evolution relation obtained from two types of entropy gives diverse understandings of the evaporation of BHs under Hawking radiation. 3. The fifth Chapter is related to BH configuration (information) entropy and the thermodynamic phase transition of $f(R)$ BH. Here, we consider a d$-$dimensional black hole (BH) in $f(R)$ gravity and analyze the effect of modified gravity on critical point parameters, the difference in number densities, and configuration entropy during the BH phase transition phenomenon. These results were also compared with charged AdS BH, the holographic dual of van der Waal's fluid, and hence the BH in modified gravity.

astro-ph.HE↗

arXiv2025

Aspects of the Black Hole Interior Volume and Entropy

The basic and conceptual notion of this work starts from the recent investigations of Marios Christodoulou and Carlo Rovelli (CR) in their paper entitled ''How big is a black hole?''. This work is related to the black hole interior volume and the entropy by Baocheng Zhang. In CR work, a spherically symmetric Schwarzschild black hole is considered and defines the interior volume, as the volume inside a sphere $S$ is the maximal proper volume of a space-like spherically symmetric $3d$ hypersurface bounded by the sphere $S$. Using this definition, they found the interior volume of a black hole is proportional to the advanced time. This is the main characteristic of this formulation. Which means that a black hole could store a large amount of infalling information. Using this special property, one can prob the nature of Hawking radiation emitted by a black hole. They also extend their result to the charged static black hole and found a consistent result. Their numerical analysis showed that the special character of this formulation is that the volume linearly increases with advancing time. Later, the CR work is followed by Baocheng Zhang, who investigated the entropy of scalar quantum modes in the interior of the Schwarzschild Black hole. He found the entropy of scalar quantum modes in the interior of Black hole is proportional to the lack hole surface area. The proportionality constant is found to be less than unity, which means that the interior entropy is less as compared to the Bekenstein Hawking entropy (horizon entropy). Note that these analyses are only applicable for black holes with mass greater than the Planck mass. If massless than Planck's mass, then one needs to understand the uncertainty relation.

gr-qc↗

arXiv2024

Short-duration gamma-ray bursts from Kerr-Newman black hole mergers

Black hole (BH) mergers are natural sources of gravitational waves (GWs) and are possibly associated with electromagnetic events. Such events from a charged rotating BH with an accretion on to it could be more energetic and ultra-short-lived if the magnetic force dominates the accretion process because the attraction of ionized fluid with a strong magnetic field around the rotating BH further amplifies the acceleration of the charged particle via a gyromagnetic effect. Thus a stronger magnetic field and gravitational pull will provide an inward force to any fluid displaced in the radial direction and move it toward the axis of rotation with an increasing velocity. After many twists during rotation and the existence of restoring agents, Such events could produce a narrow intense jet starts in the form of Poynting flux along the axis of rotation resembling the Blandford-Znajek (BZ) mechanism. We investigated a charged rotating BH and obtained characteristic results (e.g., the remnant mass, magnetic field strength, luminosity, opening angle, viewing angle, and variation of viewing angle on the SGRB luminosity detection) that have a nice coincidence with rare events having GW associated with EM counterparts. This study gives a new insight into events with a strongly magnetized disk dominating the accretion process of energy extraction.

astro-ph.HE↗

arXiv2024

The CR Volume for Black Holes and the Corresponding Entropy Variation: A Review

This paper reviews the work done on black hole interior volume, entropy, and evaporation. An insight into the basics for understanding the interior volume is presented. A general analogy to investigate the interior volume of a black hole, the associated quantum mode's entropy, and the evolution relation between the interior and exterior entropy is explained. Using this analogy, we predicted the future of information stored in a BH, its radiation, and evaporation. The results are noted in tables (\ref{tab:1}) and (\ref{tab:2}). To apply this analogy in BH space-time, we investigated the interior volume, entropy, and evaluation relation for different types of BHs. Finally, we also investigated the nature of BH radiation and the probability of particle emission during the evaporation process.

gr-qc↗

arXiv2020

Information evolution in the interior of an axially symmetric BTZ black hole

In this paper, we consider an axially symmetric $(2+1)-$dimensional rotating Banados-Teitelboim-Zanelli (BTZ) black hole to investigate its interior \textbf{information}. First, we choose a largest space-like hyper-surface at $r_v=0.45$ and calculate the maximal interior volume bound by it. We found the interior volume to increase with advance time $v$. Similarly, the \textbf{scalar} quantum mode entropy \textbf{is} also found to increase with advance time. Next\textbf{,} considering two important assumptions, an evolution relation is obtained between \textbf{the variation of scalar} quantum mode entropy and Bekenstein Hawking entropy \textbf{for an} infinitesimal interval of time. In contrast to the evolution relation of higher dimensional black holes, the characteristic feature of this relation is its increase with extremely large increase in black hole mass. Moreover, this work extends the notion of black hole evaporation idea to lower space-time dimensions.

gr-qc↗

arXiv2017

Standardization of Proton Induced X-Ray Emission for Analysis of Trace Elements in Thick Targets

This paper presents the standardization of Proton Induced X-rays Emission (PIXE) technique for the trace element analysis of thick standard samples. Three standard reference materials (SRMs) viz-\`a-vis titanium, copper and iron base alloys were used for the study due to their availability. The protons beam was accelerated up to 2.57 MeV energy by 5UDH-II tandem Pelletron accelerator and samples were irradiated at different geometry and durations. Spectrum was acquired using a multi-channel spectrum analyzer while spectrum analysis was done using a GUPIXWIN model for determination of elemental concentrations of trace elements. The obtained experimental data was compared with theoretical data and results were found in close agreement.

physics.ins-det↗