The holographic s+p model in 4D and 5D Einstein-Gauss-Bonnet gravity

TL;DR

This paper explores the effects of Gauss-Bonnet gravity terms on phase transitions in holographic s+p models within 4D and 5D Einstein-Gauss-Bonnet gravity, revealing similar qualitative behaviors across dimensions and ensemble-dependent critical parameters.

Contribution

It provides a comparative analysis of phase diagrams and critical parameters in 4D and 5D Einstein-Gauss-Bonnet holographic models, highlighting the influence of Gauss-Bonnet terms on phase transition characteristics.

Findings

Phase diagrams in 4D and 5D show similar qualitative features.

Gauss-Bonnet parameter affects critical values of nonlinear terms.

Differences in critical values between ensembles relate to phase separation phenomena.

Abstract

We study the holographic s+p model in both four dimensional (4D) and five dimensional (5D) Einstein-Gauss-Bonnet (EGB) gravity. We first show a phase diagram with the Gauss-Bonnet parameter fixed to a small value $\alpha=10^{-7}$ to choose propitiate values of $q_p/q_s$. Then we fix the value of $q_p/q_s$ and plot $\alpha-\mu$ phase diagrams to show the influence of Gauss-Bonnet term on the phase transitions in both 4D and 5D bulk, respectively. The phase diagrams in 4D and 5D present the same qualitative features, indicating similarity of 4D Einstein-Gauss-Bonnet gravity with the 5D case in holography. We also study the influences of Gauss-Bonnet parameter on the special values of the fourth order nonlinear term parameters $\lambda_s$ and $\lambda_p$, below which the condensate grows to a different direction near the critical point, that is important in realizing 1st order superfluid phase transitions. Especially, we notice that these special values are different in the canonical and grand canonical ensembles, which is closely related to the study of the spinodal region, where the phase separations occurs with the linear instability at finite wave vector.