# Axionic charged black branes with arbitrary scalar nonminimal coupling

## TL;DR

This paper constructs and analyzes four-dimensional charged black branes with nonminimal scalar coupling and axionic fields, revealing diverse thermodynamic properties and novel holographic conductivities, including perfect and Hall effect-like behaviors.

## Contribution

It introduces new black brane solutions with arbitrary scalar nonminimal coupling and axionic fields, exploring their thermodynamics and holographic conductivities.

## Key findings

- Existence of black branes with two horizon positions depending on axionic parameters.
- Identification of discrete nonminimal coupling values for extremal solutions with zero temperature.
- Discovery of conditions leading to infinite conductivity and Hall effect-like behavior in extremal cases.

## Abstract

In this paper, we construct four-dimensional charged black branes of a nonminimally coupled and self-interacting scalar field. In addition to the scalar and Maxwell fields, the model involves two axionic fields homogeneously distributed along the two-dimensional planar base manifold providing in turn a simple mechanism of momentum dissipation. Interestingly enough, the horizon of the solution can be set at two different positions, whose locations depend on the axionic parameter, and in both cases there exists a wide range of values of the nonminimal coupling parameter yielding physical acceptable solutions. For one of our solutions, the allowed nonminimal coupling parameters take discrete values and it turns out to be extremal since its has zero temperature. A complete analysis of the thermodynamical features of the solutions is also carried out. Finally, thanks to the mechanism of momentum dissipation, the holographic DC conductivities of the solutions are computed in term of the black hole horizon data, and we analyze the effects of the nonminimal coupling parameter on these conductivities. For example, we notice that for the non extremal solutions, there always exists a nonminimal coupling (which is greater than the conformal one in four dimensions) yielding perfect conductivity in the sense that the conductivity is infinite. Even more astonishing, the conductivity matrix for the extremal solutions has a Hall effect-like behavior.