arXiv subjects

Himangshu Barman

Publications and source records attributed to Himangshu Barman.

5 recordsLinked to original sources

arXiv2024

Accretion, greybody factor, quasinormal modes, power spectrum, sparsity of Hawking radiation, and weak gravitational lensing of a minimum measurable length inspired Schwarzchild black hole

In this manuscript, we delve into an analytic and numerical probe of shadow with different accretion models, quasinormal modes, Hawking radiation, and gravitational lensing to study observational impacts of quantum effect introduced throughh linear-quadratic GUP(LQG). Our investigation reveals that the shadows of LQG modified black holes are smaller and brighter than Schwarzschild black holes. To examine the impact of the quantum correction on the quasinormal mode, linear-quadratic GUP modified black holes are explored under scalar and electromagnetic field perturbation. Here, linear-quadratic GUP is used to capture quantum corrections. It is observed that the incorporation of quantum correction by linear-quadratic GUP alters the singularity structure of the black hole. To compute the quasinormal modes of this linear-quadratic GUP-inspired quantum-corrected black holes, we compute the effective potential generated under the perturbation of scalar and electromagnetic field, and then we use the sixth-order WKB approach in conjunction with the appropriate numerical analysis. We find that the greybody factor decreases with the GUP parameter $α$ implying that the probability of transmission decreases with the GUP parameter. The total power emitted by LQG modified black hole is found to be greater than that emitted by Schwarzschild black hole. Finally, we study weak gravitational lensing and make a comparison with quadratic GUP and linear GUP modified black holes.

gr-qc↗

arXiv2022

Thermodynamics of a Schwarzschild-like black hole with a minimum observable length and the radiation process of a thin accretion disc around it

We study quantum gravity effects on the thermodynamic character and the radiation process of the thin accretion disks around Schwarzschild-like black hole. The quantum gravity correction is invoked through the framework of generalization of uncertainty which is equivalent to the renormalization group improved quantum gravity and maintain the limit of the asymptotically safe preposition of gravity. It admits a free parameter that encodes the quantum effects on the spacetime geometry. It allows us to study how the thermal properties of the black hole itself and the the accretion around it disk are modified in the quantum regime. We computed explicitly the entropy, temperature, free energy, and enthalpy of the modified black hole and show its variation with with the free parameter that encodes the quantum effects. We explicitly make estimations of quantum correction to the time averaged energy flux, the temperature of the disk, the differential luminosity, and the conversion efficiency of accreting mass into radiation. We observe a conspicuous shifting of the radius of the innermost stable circular orbit (ISCO) toward small values together with an enhancement of the maximum of the values of the average thermal radiation and greater conversion efficiency of accreting mass into radiation compared to the classical gravity scenario.

gr-qc↗

arXiv2020

Bumblebee gravity and particle motion in Snyder noncommutative spacetime structures

A metric with a Lorentz violating parameter is associated with the bumblebee gravity model. We study the motion of a particle in this bumblebee background where the dynamical variables satisfy non-canonical Snyder algebra along with some critical survey on the classical observations in the bumblebee background to see how these would likely differ from Schwarzschild background. It has been found that the perihelion shift acquires a generalized expression with two independent parameters. One of these two is connected with the Lorentz violating factor and the other is involved in the Snyder algebraic formulation. We also observe that the time period of revolution, in general, acquires a Lorentz violating factor in the bumblebee background, however, for the circular orbit, it remains unchanged even in the presence of the Lorentz violating factor in the bumblebee background. The parameters used here can be constrained with the same type of conjecture used earlier.

hep-th↗

arXiv2020

On the reformulation of Thomas-Fermi model to make it compatible to the Planck-scale

Thomas-Fermi model is considered here to make it cogent to capture the Planck-scale effect with the use of a generalization of uncertainty relation. Here generalization contains both linear and quadratic terms of momentum. We first reformulate the Thomas-Fermi model for the non-relativistic case. It has been shown that it can also be reformulated for taking into account the relativistic effect. Dialectic screening for the non-relativistic cases has been studied and the expression of screening length has been found out explicitly.

physics.gen-ph↗

arXiv2020

Planck-scale effect through a new MDR

In order to the expected Planck-scale correction in the physical systems we have put forwarded a novel modified dispersion relation (MDR). It has a generalized structure. A specific choice of the function used in the construction of this MDR, it has Lorentz invariance. A toy model like relativistic harmonic oscillator has been studied to get the necessary Planck-scale correction. It has been found that each laves of harmonic oscillator acquires Planck-scale correction and the result agrees with negligible deviation with the result obtained for this system for the same purpose using generalized uncertainty relation (GUP). The relativistic Hydrogen atom problem has also been studied with this MDR and it is found that like harmonic oscillator each energy level of the Hydrogen atom too has got Planck-scale correction.

physics.gen-ph↗