arXiv subjects

B. Binaei Ghotbabadi

Publications and source records attributed to B. Binaei Ghotbabadi.

4 recordsLinked to original sources

arXiv2021

Lifshitz scaling effects on the holographic paramagnetic-ferromagnetic phase transition

We disclose the effects of Lifshitz dynamical exponent $z$ on the properties of holographic paramagnetic-ferromagnetic phase transition in the background of Lifshitz spacetime. To preserve the conformal invariance in higher dimensions, we consider the Power-Maxwell (PM) electrodynamics as our gauge field. We introduce a massive $2$-form coupled to the PM field and perform the numerical shooting method in the probe limit by assuming the PM and the $2$-form fields do not back-react on the background geometry. The obtained results indicate that the critical temperature decreases with increasing the strength of the power parameter $q$ and dynamical exponent $z$. Besides, the formation of the magnetic moment in the black hole background is harder in the absence of an external magnetic field. At low temperatures, and in the absence of an external magnetic field, our result show the spontaneous magnetization and the ferromagnetic phase transition. We find that the critical exponent takes the universal value $β= 1/2$ regardless of the parameters $q, z, d$, which is in agreement with the mean field theory. In the presence of an external magnetic field, the magnetic susceptibility satisfies the Curie-Weiss law.

hep-th↗

arXiv2021

Holographic paramagnetic-ferromagnetic phase transition of Power-Maxwell-Gauss-Bonnet black holes

Based on the shooting method, we numerically investigate the properties of holographic paramagnetism-ferromagnetism phase transition in the presence of higher order Gauss-Bonnet (\emph{GB}) correction terms on the gravity side. On the matter field side, however, we consider the effects of the Power-Maxwell (\emph{PM}) nonlinear electrodynamics on the phase transition of this system. For this purpose, we introduce a massive $2-$form coupled to \emph{PM} field, and neglect the effects of $2-$form fields and gauge field on the background geometry. We observe that increasing the strength of both the power parameter $q$ and \emph{GB} coupling constant $α$ decrease the critical temperature of the holographic model, and lead to the harder formation of magnetic moment in the black hole background. Interestingly, we find out that at low temperatures, the spontaneous magnetization and ferromagnetic phase transition happen in the absence of external magnetic field. In this case, the critical exponent for magnetic moment has the mean field value, $1/2$, regardless of the values of $q$ and $α$. In the presence of external magnetic field, however, the magnetic susceptibility satisfies the Curie-Weiss law.

hep-th↗

arXiv2018

One-dimensional backreacting holographic superconductors with exponential nonlinear electrodynamics

In this paper, we investigate the effects of nonlinear exponential electrodynamics as well as backreaction on the properties of one-dimensional $s$-wave holographic superconductors. We continue our study both analytically and numerically. In analytical study, we employ the Sturm-Liouville method while in numerical approach we perform the shooting method. We obtain a relation between the critical temperature and chemical potential analytically. Our results show a good agreement between analytical and numerical methods. We observe that the increase in the strength of both nonlinearity and backreaction parameters causes the formation of condensation in the black hole background harder and critical temperature lower. These results are consistent with those obtained for two dimensional $s$-wave holographic superconductors.

hep-th↗

arXiv2017

The study of uniaxial-biaxial phase transition of confined hard ellipsoids using density functional theory

The density profiles and corresponding order parameters of the hard ellipsoids confined between two hard walls and also in contact with a single hard wall are studied using the density functional theory. The Hyper-Netted Chain (HNC) approximation is used to write excess grand potential of the system with respect to the bulk value. To simplify the calculations we use restricted orientation model (ROM) for the orientation of ellipsoids to find the density profiles and order parameters. Density functional theory shows that there is a uniaxial-biaxial phase transition near a single hard wall and also between two hard walls for a fluid consisting of uniaxial hard ellipsoidal particles with finite elongation.

cond-mat.soft↗