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H. Hassanabadi

Publications and source records attributed to H. Hassanabadi.

At least 37 records · Page 2Linked to original sources
arXiv2023

Gravitational traces of bumblebee gravity in metric-affine formalism

This work explores various manifestations of bumblebee gravity within the metric-affine formalism. We investigate the impact of the Lorentz violation parameter, denoted as $X$, on the modification of the Hawking temperature. Our calculations reveal that as $X$ increases, the values of the Hawking temperature attenuate. To examine the behavior of massless scalar perturbations, specifically the quasinormal modes, we employ the WKB method. The transmission and reflection coefficients are determined through our calculations. The outcomes indicate that a stronger Lorentz-violating parameter results in slower damping oscillations of gravitational waves. To comprehend the influence of the quasinormal spectrum on time-dependent scattering phenomena, we present a detailed analysis of scalar perturbations in the time-domain solution. Additionally, we conduct an investigation on shadows, revealing that larger values of $X$ correspond to larger shadow radii. Furthermore, we constrain the magnitude of the shadow radii using the EHT horizon-scale image of $Sgr A^*$. Finally, we calculate both the time delay and the deflection angle.

gr-qc↗
arXiv2023

Gravitational signatures of a non--commutative stable black hole

This work investigates several key aspects of a non--commutative theory with mass deformation. We calculate thermodynamic properties of the system and compare our results with recent literature. We examine the \textit{quasinormal} modes of massless scalar perturbations using two approaches: the WKB approximation and the Pöschl--Teller fitting method. Our results indicate that stronger non--commutative parameters lead to slower damping oscillations of gravitational waves and higher partial absorption cross sections. Furthermore, we study the geodesics of massless and massive particles, highlighting that the non--commutative parameter $Θ$ significantly impacts the paths of light and event horizons. Also, we calculate the shadows, which show that larger values of $Θ$ correspond to larger shadow radii, and provide some constraints on $Θ$ applying the observation of Sgr $A^{*}$ from the Event Horizon Telescope. Finally, we explore the deflection angle in this context.

gr-qc↗
arXiv2023

Thermal analysis of photon-like particles in rainbow gravity

This work is devoted to study the thermodynamic behavior of photon--like particles within the \textit{rainbow} gravity formalism. To to do this, we chose two particular ansatzs to accomplish our calculations. First, we consider a dispersion relation which avoids UV divergences, getting a positive effective cosmological constant. We provide \textit{numerical} analysis for the thermodynamic functions of the system and bounds are estimated. Furthermore, a phase transition is also expected for this model. Second, we consider a dispersion relation employed in the context of \textit{Gamma Ray Bursts}. Remarkably, for this latter case, the thermodynamic properties are calculated in an \textit{analytical} manner and they turn out to depend on the harmonic series $H_{n}$, gamma $Γ(z)$, polygamma $ψ_{n}(z)$ and zeta Riemann functions $ζ(z)$.

gr-qc↗
arXiv2023

Dark matter spike around Bumblebee black holes

The effects of dark matter spike in the vicinity of the supermassive black hole, located at the center of M87 (the Virgo A galaxy), are investigated within the framework of the so-called Bumblebee Gravity. Our primary aim is to determine whether the background of spontaneous Lorentz symmetry breaking has a significant effect on the horizon, ergo-region, and shadow of the Kerr Bumblebee black hole in the spike region. For this purpose, we first incorporate the dark matter distribution in a Lorentz-violating spherically symmetric space-time as a component of the energy-momentum tensors in the Einstein field equations. This leads to a space-time metric for a Schwarzschild Bumblebee black hole with a dark matter distribution in the spike region and beyond. Subsequently, this solution is generalized to a Kerr Bumblebee black hole through the use of the Newman-Janis-Azreg-Aïnou algorithm. Then, according to the available observational data for the dark matter spike density and radius, and the Schwarzschild radius of the supermassive black hole in Virgo A galaxy, we examine the shapes of shadow and demonstrate the influence of the spin parameter $a$, the Lorentz-violating parameter $\ell$ and the corresponding dark matter halo parameters $ρ_{0}$ and $r_{0}$ on the deformation and size of the shadow.

gr-qc↗
arXiv2023

Thermodynamics of a quantum ring modified by Lorentz violation

In this work, we investigate the consequences of Lorentz-violating terms in the thermodynamic properties of a 1-dimensional quantum ring. Particularly, we use the ensemble theory to obtain our results of interest. The thermodynamic functions as well as the spin currents are calculated as a function of the temperature. We observe that parameter $ξ$, which triggers the Lorentz symmetry breaking, plays a major role in low temperature regime. Finally, depending on the configuration of the system, electrons can rotate in two different directions: clockwise and counterclockwise.

quant-ph↗
arXiv2023

Thermodynamics and evaporation of a modified Schwarzschild black hole in a non--commutative gauge theory

In this work, we study the thermodynamic properties on a non--commutative background via gravitational gauge field potentials. This procedure is accomplished after contracting de Sitter (dS) group, $\mathrm{SO}(4,1)$, with the Poincarè group, $\mathrm{ISO}(3,1)$. Particularly, we focus on a static spherically symmetric black hole. In this manner, we calculate the modified Hawking temperature and the other deformed thermal state quantities, namely, entropy, heat capacity, Helmholtz free energy and pressure. Finally, we also investigate the black hole evaporation process in such a context.

hep-th↗
arXiv2022

Investigation of the Dunkl-Schrödinger equation for Position Dependent Mass in the presence of a Lie algebraic approach

Recent studies have shown that the use of Dunkl derivatives instead of ordinary derivatives leads to deriving parity-dependent dynamic solutions. According to this motivation in this manuscript, we formulate the Dunkl-Schrödinger equation within the position-dependent mass formalism and derive an algebraic solution out of it. Our systematic approach lets us observe some new findings in addition to the earlier ones. For example, we find that the solution of the Dunkl-Schröodinger equation with position-dependent mass cannot be considered independent of the choice of parameters. Similarly, through the sl(2) algebra, the energy spectrum and the corresponding wave functions are derived in terms of possible Dunkl, ($μ$), and mass, ($α$), parameters.

quant-ph↗
arXiv2022

Relativistic Solutions of Generalized-Dunkl Harmonic and Anharmonic Oscillators

Dunkl derivative enriches solutions by discussing parity due to its reflection operator. Very recently, one of the authors of this manuscript presented one of the most general forms of Dunkl derivative that depends on three Wigner parameters to have a better tuning. In this manuscript, we employ the latter generalized Dunkl derivative in a relativistic equation to examine two-dimensional harmonic and anharmonic oscillators solutions. We obtain the solutions by Nikiforov-Uvarov and QES methods, respectively. We show that degenerate states can occur according to the Wigner parameter values.

quant-ph↗
arXiv2022

Linear and nonlinear optical properties in spherical quantum dots: Inversely quadratic Hellmann potential

The aims of the reported work are to provide new insights into the quantum dot optical properties confined in an inverse of a quadratic Hellmann potential. The Schrödinger equation is solved using the Nikiforov-Uvarov (NU) method, in order to obtain the analytical expressions of the eigenenergies and the eigenfunctions. The linear together with the third-order nonlinear changes in absorption coefficients and refractive index are investigated using the density matrix formalism. The absorption coefficients and the refractive index changes are strong related to the structure parameters and the optical intensity.

cond-mat.mes-hall↗
arXiv2021

Thermodynamics of the Schwarzschild and Reissner-Nordström black holes under higher-order generalized uncertainty principle

In this manuscript, the modification of thermodynamic properties of Schwarzschild and Reissner-Nordström black holes in the presence of higher-order generalized uncertainty principle (GUP) have been investigated. We considered heuristic analysis versus the behavior of a particle that is absorbed by the black hole, and then, we studied the thermodynamic properties of the black holes such as temperature-mass, temperature-charge-mass, entropy, and heat capacity functions up to the first and second-order of the GUP parameter. We compared the behaviors of the GUP-corrected thermodynamic properties for both black holes with graphical methods.

gr-qc↗
arXiv2021

Interaction of the generalized Duffin-Kemmer-Petiau equation with a non-minimal coupling under the cosmic rainbow gravity

In this study, we survey the generalized Duffin-Kemmer-Petiau oscillator containing a non-minimal coupling interaction in the context of rainbow gravity in the presence of cosmic topological defects in space-time. In this regard, we intend to investigate relativistic quantum dynamics of a spin-0 particle under the modification of the dispersion relation according to the Katanaev-Volovich geometric approach. Thus, based on the geometric model, we study the aforementioned bosonic system under the modified background by a few rainbow functions. In this way, by using an analytical method, we acquire energy eigenvalues and corresponding wave functions corresponding to each scenario. Regardless of rainbow gravity function selection, the energy eigenvalue can present symmetric, anti-symmetric, and symmetry breaking characteristics. Besides, one can see that the deficit angular parameter plays an important role in the solutions.

quant-ph↗
arXiv2021

Duffin-Kemmer-Petiau particles in the presence of the spiral dislocation

In this study, we investigated the influence of the topological defects space-time with a spiral dislocation on a spin-zero boson field by using the Duffin-Kemmer-Petiau (DKP) equation. To be more specific, we solved the generalized spin-zero DKP equation in the presence of a spiral dislocation exactly. We derived the wave function and corresponding energy eigenvalues for two cases, in the absence and presence of a static potential by using analytical methods. We numerically demonstrated the effect of the spiral dislocation on the solutions.

hep-th↗
arXiv2021

Interaction of the magnetic quadrupole moment of a non-relativistic particle with an electric field in the background of screw dislocations with a rotating frame

In this study, we considered a moving particle with a magnetic quadrupole moment in an elastic medium in the presence of a screw dislocation. We assumed a radial electric field in a rotating frame that leads a uniform effective magnetic field perpendicular to the plane of motion. We solved the Schrödinger equation to derive wave and energy eigenvalue functions by employing analytical methods for two interaction configurations: in the absence of potential and in the presence of a static scalar potential. Due to the topological defect in the medium, we observed a shift in the angular momentum quantum number which affects the energy eigenvalues and the wave function of the system.

quant-ph↗
arXiv2021

Electric quadrupole moment of a neutral non-relativistic particle in the presence of screw dislocation

In this contribution, we investigate the interaction between electric and magnetic fields with an electric quadrupole moment of a spinless particle moving in an elastic medium which has a topological defect (screw dislocation). By considering this interaction, the Schrödinger equation is exactly solved by using the analytical method. Thus, the eigenfunction and energy eigenvalues for two configurations are found. Meanwhile, by observing a shift in the angular momentum quantum number, the energy eigenvalues and the wave function of the system are modified, due to the screw dislocation in the medium.

quant-ph↗
arXiv2020

The generalized Klein-Gordon oscillator in a Cosmic Space-Time with a Space-Like Dislocation and the Aharonov-Bohm Effect

In the present work, we investigated the quantum behavior of a charged particle that is under the effect of a uniform magnetic external field. We assumed that space-time has a space-like dislocation with an internal magnetic flux. We examined two different types of potential energies that are known as the pseudo harmonic and Cornell type potential energies, with the nonminimal coupling. We observed the Aharonov-Bohm effect in both cases. We extended the analysis on the energy spectrum functions to the different limits.

quant-ph↗
arXiv2020

Decay properties of beauty and charm mesons within Isgur-Wise function formalism

We investigate the decay properties of some beauty and charm mesons with a phenomenological potential model. First, we consider the nonrelativistic Hamiltonian of the mesonic system with Coulomb plus exponential terms and study the wave function and the energy of the system using the variational approach. Thereby, we compute the masses, the decay constants, the leptonic branching fractions of heavy-light mesons and the mixing mass parameter $Δ{m_{B_q}}$. We study the radiative leptonic decay widths of ${D_s} \to γ\ell \bar ν$, ${D^ - } \to γ\ell \bar ν$ and the semileptonic decay widths of ${\bar B_{(s)}} \to {D_{(s)}}\ell \bar ν$, ${\bar B_{(s)}} \to D_{(s)}^*\ell \bar ν$. Using Isgur-Wise functions, we calculate the branching ratios of $B \to {D^{(*)}}π$ and two-body nonleptonic decay of $D \to Kπ$. Our results are consistent with other theoretical models and the experimental results.

hep-ph↗
arXiv2019

Analysis of black hole thermodynamics under Generalized uncertainty principle from the doubly special relativity

In this paper, we investigate effect of the generalized uncertainty principle (GUP) under the doubly special relativity (DSR) on the thermodynamics properties of the topological charged black hole in Anti-de Sitter (AdS) space only in the spherical horizon case have. Our study is based on a heuristic analysis of a particle which is captured by the black hole. We also report here some results of a usual analytical computation. However, we obtain the black hole thermodynamic properties as familiar concepts such as temperature, entropy and heat capacity under DSR-GUP. we also compare our both analytical results. Beside we discuss the behavior of the corrected thermodynamic properties vs. changes of black hole characteristics under different condition.

physics.gen-ph↗