Hamid Reza Salahi | Searcharxiv

arXiv2016

Effects of Backreaction on Power-Maxwell Holographic Superconductors in Gauss-Bonnet Gravity

We analytically and numerically investigate the properties of s-wave holographic superconductors by considering the effects of scalar and gauge fields on the background geometry in five dimensional Einstein-Gauss-Bonnet gravity. We assume the gauge field to be in the form of the Power-Maxwell nonlinear electrodynamics. We employ the Sturm-Liouville eigenvalue problem for analytical calculation of the critical temperature and the shooting method for the numerical investigation. Our numerical and analytical results indicate that higher curvature corrections affect condensation of the holographic superconductors with backreaction. We observe that the backreaction can decrease the critical temperature of the holographic superconductors, while the Power-Maxwell electrodynamics and Gauss-Bonnet coefficient term may increase the critical temperature of the holographic superconductors. We find that the critical exponent has the mean-field value $β=1/2$, regardless of the values of Gauss-Bonnet coefficient, backreaction and Power-Maxwell parameters.

gr-qc↗

arXiv2016

Analytical and Numerical Study of Gauss-Bonnet Holographic Superconductors with Power-Maxwell Field

We provide an analytical as well as a numerical study of the holographic $s$-wave superconductors in Gauss-Bonnet gravity with Power-Maxwell electrodynamics. We limit our study to the case where scalar and gauge fields do not have an effect on the background metric. We use a variational method, based on Sturm-Liouville eigenvalue problem for our analytical study, as well as a numerical shooting method in order to compare with our analytical results. Interestingly enough, we observe that unlike Born-Infeld-like nonlinear electrodynamics which decrease the critical temperature compared to the linear Maxwell field, the Power-Maxwell electrodynamics is able to increase the critical temperature of the holographic superconductors in the sublinear regime. We find that requiring the finite value for the gauge field on the asymptotic boundary $r\rightarrow \infty$, restricts the power parameter, $q$, of the Power-Maxwell field to be in the range $1/2<q<{(d-1)}/{2}$. Our study indicates that it is quite possible to make condensation \emph{easier} as $q$ \emph{decreases} in its allowed range. We also find that for all values of $q$, the condensation can be affected by the Gauss-Bonnet coefficient $α$. However, the presence of the Gauss-Bonnet term makes the transition slightly harder. Finally, we obtain an analytic expression for the order parameter and thus obtain the associated critical exponent near the phase transition. We find that the critical exponent has its universal value of $β=1/2$ regardless of the parameters $q$, $α$ as well as dimension $d$, consistent with mean-field values obtained in previous studies.

gr-qc↗