Generalized Superconductors and Holographic Optics

TL;DR

This paper investigates the optical properties of generalized holographic s-wave superconductors in different black hole backgrounds, revealing conditions under which negative Depine-Lakhtakia index can occur, indicating potential novel optical phenomena.

Contribution

It introduces a study of holographic superconductors in R-charged and Lifshitz black hole backgrounds, analyzing their optical responses and identifying conditions for negative index behavior.

Findings

Negative Depine-Lakhtakia index appears at low frequencies in R-charged black hole backgrounds.

Such negative index effects are absent in Lifshitz backgrounds.

Numerical cut-off values for negative index occurrence are established.

Abstract

We study generalized holographic s-wave superconductors in four dimensional R-charged black hole and Lifshitz black hole backgrounds, in the probe limit. We first establish the superconducting nature of the boundary theories, and then study their optical properties. Numerical analysis indicates that a negative Depine-Lakhtakia index may appear at low frequencies in the theory dual to the R-charged black hole, for certain temperature ranges, for specific values of the charge parameter. The corresponding cut-off values for these are numerically established in several cases. Such effects are seen to be absent in the Lifshitz background where this index is always positive.