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Hassan Hassanabadi

Publications and source records attributed to Hassan Hassanabadi.

At least 55 records · Page 3Linked to original sources
arXiv2024

Critical behavior and Joule-Thomson expansion of charged AdS black holes surrounded by exotic fluid with modified Chaplygin equation of state

By considering the concept of a unified single fluid model, referred to as the modified Chaplygin gas (MCG), which amalgamates dark energy and dark matter. In this study, we explore the thermodynamic characteristics of charged anti-de Sitter (AdS) black holes existing in an unconventional fluid accompanied by MCG. To accomplish this objective, we derive the equations of state by regarding the charge $Q^{2}$ as a thermodynamic variable. The impact of MCG parameters on the critical thermodynamic quantities ($ψ_{c}$, $T_{c}$, $Q_{c}^{2}$) are examined, followed by a detailed analysis of the $Q^{2}-ψ$ diagram. To provide a clearer explanation of the phase transition, we present an analysis of the Gibbs free energy. It is important to note that if the Hawking temperature exceeds the critical temperature, there is a distinct pattern observed known as swallowtail behavior. This indicates that the system undergoes a first-order phase transition from a smaller black hole to a larger one. The critical exponent of the system is found to be in complete agreement with that of the van der Waals fluid system. Furthermore, we investigate the impact of MCG parameters and black hole charge on the Joule-Thomson (J-T) expansion in the extended phase space. The J-T coefficient is examined to pinpoint the exact region experiencing cooling or heating, the observation reveals that the presence of negative heat capacity results in the occurrence of a cooling process. In addition, it is worth noting that the certain parameters exert a significant influence on the ratio $\frac{T_{min}}{T_{c}}$. The parameters $γ$ and $β$ have a non-negligible effect on the isenthalpy curve.

gr-qc↗
arXiv2023

The Dunkl oscillator on a space of nonconstant curvature: an exactly solvable quantum model with reflections

We introduce the Dunkl-Darboux III oscillator Hamiltonian in N dimensions, defined as a $λ-$deformation of the N-dimensional Dunkl oscillator. This deformation can be interpreted either as the introduction of a non-constant curvature related to $λ$ on the underlying space or, equivalently, as a Dunkl oscillator with a position-dependent mass function. This new quantum model is shown to be exactly solvable in arbitrary dimension N, and its eigenvalues and eigenfunctions are explicitly presented. Moreover, it is shown that in the two-dimensional case both the Darboux III and the Dunkl oscillators can be separately coupled with a constant magnetic field, thus giving rise to two new exactly solvable quantum systems in which the effect of a position-dependent mass and the Dunkl derivatives on the structure of the Landau levels can be explicitly studied. Finally, the whole 2D Dunkl-Darboux III oscillator is coupled with the magnetic field and shown to define an exactly solvable Hamiltonian, where the interplay between the $λ$-deformation and the magnetic field is explicitly illustrated.

quant-ph↗
arXiv2023

Lorentz violation in a family of $(1+2)$-dimensional wormhole

We study neutral Dirac particles confined to a family of $(1+2)$-dimensional wormholes arising from surfaces of revolution with a constant negative Gaussian curvature, in the framework of a comprehensive effective field theory allowing deviations from Lorentz symmetry: the gravitational standard-model extension (SME). The Dirac particles are described with a fixed background tensor field that rules the Lorentz symmetry violation in the CPT-even gauge sector of SME. We implement this geometrical approach by incorporating non-minimal couplings that possibly induce a Lorentz-symmetry violating term in the modified Dirac equation. We also analyze the exact analytical solutions of the corresponding modified Dirac equation in the presence of a peculiar external magnetic field.

math-ph↗
arXiv2023

Topology of nonlinearly charged black hole chemistry via massive gravity

The classification of critical points of charged topological black holes (TBHs) in anti-de Sitter spacetime (AdS) under the Power Maxwell Invariant (PMI)-massive gravity is accomplished within the framework of black hole chemistry (BHC). Considering the grand canonical ensemble (GCE), we show that $d=4$ black hole have only one topological class, whereas $d\ge 5$ black holes belong to two different topology classes. Furthermore, the conventional critical point characterized by negative topological charge coincides with the maximum extreme point of temperature; and the novel critical point featuring opposite topological charge corresponds to the minimum extreme point of temperature. With increasing pressure, new phases emerge at the novel critical point while disappear from the conventional one. Moreover, a atypical van der Waals (vdW) behavior is found in $d\ge 6$ dimensions, and the anomaly disappears at the traditional critical point. In the limit of nonlinearity parameter $s\to1$, different topology classes are only obtained in the GCE and they may not exist within the canonical ensemble. With the absence of electric potential $Φ$, the neutral TBHs share the same topological classification results as the charged TBHs in the GCE of Maxwell-massive gravity.

gr-qc↗
arXiv2023

Behavior of the Feshbach-Villars oscillator (FVO) in Gürses space-time under Coulomb-type potential

Our research aims to investigate how the gravitational field influences the spectroscopic structure of the Feshbach-Villars oscillator in Gürses space-time. To achieve this, we utilize the first-order Feshbach-Villars version of the Klein-Gordon equation, which is a relativistic wave equation for spinless particles. We examine the oscillator's quantum mechanical behavior in the presence of a Coulomb-type potential, and calculate the resulting wave functions and energy levels for both free and interacting scenarios. In addition, we study the interaction between the Coulomb-type potential and Gürses space-time affects the Feshbach-Villars oscillator's behavior, specifically with regard to its spectroscopic structure. This study has important implications for our understanding of the interplay between quantum mechanics, relativity, and gravitational fields at the microscopic level.

hep-th↗
arXiv2023

Quantum mechanics on a circle with a finite number of α-uniformly distributed points

In this paper, quantum mechanics on a circle with finite number of α-uniformly distributed points is discussed. The angle operator and translation operator are defined. Using discrete angle representation, two types of discrete angular momentum operators and Hermitian Hamiltonian on a circle with d α-distributed discrete angles are constructed. The energy levels are computed for a free particle on a circle where the wave function is defined in the d α-distributed discrete angles.

quant-ph↗
arXiv2023

Approximate analytical solutions of the Schrödinger equation with Hulthén potential in the global monopole spacetime

In this paper, we study the nonrelativistic quantum mechanics of an electron in a spacetime containing a topological defect. We also consider that the electron is influenced by the Hulthén potential. In particular, we deal with the Schrödinger equation in the presence of a global monopole. We obtain approximate solutions for the problem, determine the scattering phase shift and the $S$-matrix, and analyze bound states.

quant-ph↗
arXiv2023

Joule-Thomson expansion of charged dilatonic black holes

Based on the Einstein-Maxwell theory, the Joule-Thomson (J-T) expansion of charged dilatonic black holes (the solutions are neither flat nor AdS) in $(n+1)$-dimensional spacetime is studied herein. To this end, we analyze the effects of the dimension $n$ and dilaton field $α$ on J-T expansion. An explicit expression for the J-T coefficient is derived, and consequently, a negative heat capacity is found to lead to a cooling process. In contrast to its effect on the dimension, the inversion curve decreases with charge $Q$ at low pressures, whereas the opposite effect is observed at high pressures. We can observe that with an increase in the dimension $n$ or parameter $α$, both the pressure cut-off point and the minimum inversion temperature $T_{min}$ change. Moreover, we analyze the ratio $T_{min}/T_{c}$ numerically and discover that the ratio is independent of charge; however, it depends on the dilaton field and dimension: for $n=3$ and $α=0$, the ratio is 1/2. The dilaton field is found to enhance the ratio. In addition, we identify the cooling-heating regions by investigating the inversion and isenthalpic curves, and the behavior of the minimum inversion mass $M_{min}$ indicates that this cooling-heating transition may not occur under certain special conditions.

gr-qc↗
arXiv2022

Quantum corrections to the quasinormal modes of the Schwarzschild black hole

Based on the minimum measurable momentum concepts associated with the quantum gravity effects acting on the large-scale dynamics of the universe, we study the quantum effect of the EUP on the Hawking evaporation of the black hole. The results show the quantum corrections may shorten the lifetime of the massive black hole. To verify the new EUP on the black hole stability, the scalar field and electromagnetic field are derived and the time evolution of the black hole is analyzed in terms of the time domain integration method, the quantum effect alters the oscillation and decay time of black hole. Furthermore, we use the WKB numerical approximation method to calculate the quasinormal mode frequencies and analyze the influence of the EUP parameter $α$ on the scattering problem. This shows that the EUP significantly increases the area of the total absorption cross-section of the black hole.

gr-qc↗
arXiv2022

The influence of Aharonov-Casher effect on the generalized Dirac oscillator in the cosmic string space-time

In this manuscript, we investigate the influence of the Aharonov-Casher effect on the generalized Dirac oscillator containing the Coulomb-type potential function related to a relativistic neutral particle having a permanent magnetic dipole moment interacting with the external electromagnetic fields in (1+2)-dimensional cosmic string space-time. The eigenfunctions and energy eigenvalues of such a Dirac oscillator are derived by using the Nikifornov-Uvarov method. We indicate that implementing the scenario gives the relativistic modified exact analytical solutions. In this way, we can see that the degeneracy of the relevant relativistic energy eigenvalues is broken by depending on the Coulomb strength parameter under the influence of the curvature effect and the Aharonov-Casher effect.

quant-ph↗
arXiv2021

Superintegrability on the Dunkl oscillator model in three-Dimensional spaces of constant curvature

This paper has studied the three-dimensional Dunkl oscillator models in a generalization of superintegrable Euclidean Hamiltonian systems to curved ones. These models are defined based on curved Hamiltonians, which depend on a deformation parameter of underlying space and involve reflection operators. Their symmetries are obtained by the Jordan-Schwinger representations in the family of the Cayley-Klein orthogonal algebras using the creation and annihilation operators of the dynamical $sl_{-1}(2)$ algebra of the one-dimensional Dunkl oscillator. The resulting algebra is a deformation of $so_{κ_1κ_2}(4)$ with reflections, which is known as the Jordan-Schwinger-Dunkl algebra $jsd_{κ_1κ_2}(4)$. Hence, this model is shown to be maximally superintegrable. On the other hand, the superintegrability of the three-dimensional Dunkl oscillator model is studied from the factorization approach viewpoint. The spectrum of this system is derived through the separation of variables in geodesic polar coordinates, and the resulting eigenfunctions are algebraically given in terms of Jacobi polynomials.

nlin.SI↗
arXiv2021

DKP oscillator in the presence of a spinning cosmic string

We investigate the modification of gravitational fields generated by topological defects on a generalized Duffin-Kemmer-Petiau (DKP) oscillator for spin-0 particle under spinning cosmic string background. The generalized DKP oscillator equation under spinning cosmic string background is established, and the impact of the Cornell potential on the generalized DKP oscillator is presented. We give the influence of space-time and potential parameters on energy levels.

quant-ph↗
arXiv2021

Resolution of the spin paradox in the Nilsson model

In the well-known Nilsson diagrams, depicting the dependence of the nuclear single-particle energy levels on quadrupole deformation, a spin paradox appears {as the deformation sets in, leading from spherical shapes to prolate deformed shapes with cylindrical symmetry}. Bunches of levels corresponding to a spherical shell model orbital, sharing the same orbital angular momentum and the same total angular momentum, appear to correspond to Nilsson energy levels, labeled by asymptotic quantum numbers in cylindrical coordinates, some of which have spin up, while some others have spin down. Furthermore, for some orbitals the correspondence between spherical shell model quantum numbers and Nilsson asymptotic quantum numbers is not the same for protons and for neutrons. Introducing a new rule of correspondence between the two sets of quantum numbers, we show that the spin paradox is resolved and full agreement between the proton and neutron Nilsson diagrams is established. The form of the Nilsson diagrams as a function of the quadrupole deformation remains unchanged, the only difference between the new diagrams and the traditional ones being the mutual exchange of the Nilsson labels for certain pairs of single-particle energy levels.

nucl-th↗
arXiv2021

The study of the generalized Klein-Gordon oscillator in the context of the Som-Raychaudhuri space-time

In this paper we study the relativistic scalar particle described by the Klein-Gordon interacts with the uniform magnetic field in the context of the Som-Raychaudhuri space-time. Based on the property of the biconfluent Heun function equation, the corresponding Klein-Gordon oscillator and generalized Klein-Gordon oscillator under considering the Coulomb potential are separately investigated, and the analogue of the Aharonov-Bohm effect is analyzed in this scenario. On this basis, we also give the influence of different parameters including the parameter α and oscillator frequency ω, and the potential parameter ξ2 on the energy eigenvalues of the considered systems.

quant-ph↗
arXiv2020

Investigation of Unruh temperature of Black holes by using of EGUP formalism

In this paper, we have used the extended generalized uncertainty principle to investigate the Unruh temperature and thermodynamic properties of a black hole. We started with a brief perusal of the Heisenberg uncertainty principle and continue with some physical and mathematical discussion for obtaining the generalized and the extended generalized uncertainty principle. Then, we obtained the Unruh temperature, mass-temperature, specific heat, and entropy functions of a black hole. We enriched the paper with graphical analysis as well as their comparisons.

gr-qc↗
arXiv2020

Shell model structure of proxy-SU(3) pairs of orbitals

The Nilsson orbitals used in the substitutions occurring in the proxy-SU(3) scheme, which are the orbitals bearing the maximum value of total angular momentum in each shell, have an extremely simple structure in the shell model basis |N l j Omega>, with each Nilsson orbital corresponding to a single shell model eigenvector. This simple structure is valid at all deformations for these orbitals, while in other orbitals it is valid only at small deformations. Nilsson 0[110] pairs are found to correspond to |1 1 1 0> pairs in the spherical shell model basis, paving the way for using the proxy-SU(3) approximation within the shell model.

nucl-th↗
arXiv2020

Research on the new form of higher-order generalized uncertainty principle in quantum system

This paper proposes a new high-order generalized uncertainty principle, which can modify the momentum operator and position operator simultaneously. Moreover, the new form of GUP is consistent with the viewpoint of the existence of the minimum length uncertainty and the maximum observable momentum proposed by the mainstream quantum gravity theory. By using the new GUP, the maximum localization state and position eigenfunction are discussed, and the corresponding conclusions are compared with the existing literature. The harmonic oscillator is further discussed at the end of this article as an example.

quant-ph↗