Analytic study of superradiant stability of Kerr–Newman black holes under charged massive scalar perturbation

The superradiant stability of a Kerr–Newman black hole and charged massive scalar perturbation is investigated. We treat the black hole as a background geometry and study the equation of motion of the scalar perturbation. From the radial equation of motion, we derive the effective potential experienced by the scalar perturbation. By a careful analysis of this effective potential, it is found that when the inner and outer horizons of Kerr–Newman black hole satisfy $$\frac{r_-}{r_+}\leqslant \frac{1}{3}$$ r - r + ⩽ 1 3 and the charge-to-mass ratios of scalar perturbation and black hole satisfy $$ \frac{q}{\mu }\frac{Q}{ M}>1 $$ q μ Q M > 1 , the Kerr–Newman black hole and scalar perturbation system is superradiantly stable.

Lyapunov exponent, ISCO and Kolmogorov–Senai entropy for Kerr–Kiselev black hole

Geodesic motion has significant characteristics of space-time. We calculate the principle Lyapunov exponent (LE), which is the inverse of the instability timescale associated with this geodesics and Kolmogorov–Senai (KS) entropy for our rotating Kerr–Kiselev (KK) black hole. We have investigate the existence of stable/unstable equatorial circular orbits via LE and KS entropy for time-like and null circular geodesics. We have shown that both LE and KS entropy can be written in terms of the radial equation of innermost stable circular orbit (ISCO) for time-like circular orbit. Also, we computed the equation marginally bound circular orbit, which gives the radius (smallest real root) of marginally bound circular orbit (MBCO). We found that the null circular geodesics has larger angular frequency than time-like circular geodesics ($$Q_o > Q_{\sigma }$$ Q o > Q σ ). Thus, null-circular geodesics provides the fastest way to circulate KK black holes. Further, it is also to be noted that null circular geodesics has shortest orbital period $$(T_{photon}< T_{ISCO})$$ ( T photon < T ISCO ) among the all possible circular geodesics. Even null circular geodesics traverses fastest than any stable time-like circular geodesics other than the ISCO.

Semiclassical treatment of an attractive inverse-square potential in an elastic medium with a disclination

We analyze the interaction of the induced electric dipole moment of a neutral particle with an electric field in elastic medium with a charged disclination from a semiclassical point of view. We show that the interaction of the induced electric dipole moment of a neutral particle with an electric field can yield an attractive inverse-square potential, where it is influenced by the topology of the disclination. Then, by using the Wentzel, Kramers and Brillouin approximation based on the Langer transformation, we show that the centrifugal term of the radial equation must be modified due to the influence of the topology of the disclination. Besides, we obtain the bound states solutions to the Schrödinger equation.

The study of the generalized boson oscillator in a chiral conical space–time

Our work mainly study the relativistic generalized boson oscillator namely generalized Duffin–Kemmer–Petiau (DKP) oscillator with the function [Formula: see text] considered as the Cornell potential under the chiral conical space–time background. We obtain the wave function and energy spectrum of radial equation by using commonly used the Nikiforov–Uvarov method. It is shows that the energy spectrum of the generalized DKP oscillator depend explicitly on the angular deficit [Formula: see text], related rotation parameter [Formula: see text] and torsion parameter [Formula: see text], which characterize the global structure of the metric in the chiral conical space–time. In addition, the Cornell potential parameters [Formula: see text] have non-negligible influence on the energy spectrum of the studied systems.

Generalized Dirac oscillator with κ-Poincaré algebra

In this paper, the generalized Dirac oscillator with [Formula: see text]-Poincaré algebra is structured by replacing the momentum operator p with [Formula: see text] in [Formula: see text]-deformation Dirac equation. The deformed radial equation is derived for this model. Particularly, by solving the deformed radial equation, the wave functions and energy spectra which depend on deformation parameter [Formula: see text] have been obtained for these quantum systems with [Formula: see text] being a Yukawa-type potential, inverse-square-type singular potential and central fraction power singular potential in two-dimensional space, respectively. The results show that the deformation parameter [Formula: see text] can lead to decreasing of energy levels for the above quantum systems. At the same time, the degeneracy of energy spectra has been discussed and the corresponding conditions of degeneracy have been given for each case.

The Deformation Dependent Mass Davidson Model

The Deformation Dependent Mass Davidson Model is an extension of the well known Bohr-Mottelson Hamiltonian for the atomic nuclei. It primarily refers to the mass dependence on the deformation and secondary to the Davidson behavior for the potential of the Ø-vibration. This article will be devoted solely in the solution of the radial equation. Fitting results for the 162Dy and 238U ground state, β1 and γ1 bands are also presented.

Analysis of the interaction of an electron with radial electric fields in the presence of a disclination

We consider an elastic medium with a disclination and investigate the topological effects on the interaction of a spinless electron with radial electric fields through the WKB (Wentzel, Kramers, Brillouin) approximation. We show how the centrifugal term of the radial equation must be modified due to the influence of the topological defect in order that the WKB approximation can be valid. Then, we search for bound states solutions from the interaction of a spinless electron with the electric field produced by this linear distribution of electric charges. In addition, we search for bound states solutions from the interaction of a spinless electron with radial electric field produced by uniform electric charge distribution inside a long non-conductor cylinder.