Magneto-thermal transport implies an incoherent Hall conductivity

TL;DR

This paper demonstrates that accounting for incoherent Hall conductivity is essential for accurately describing magnetothermal transport in magnetohydrodynamics, especially beyond the zero magnetic field limit, with applications to holographic models.

Contribution

It introduces the concept of incoherent Hall conductivity in magnetohydrodynamics and calculates it for the dyonic black hole, improving the match with thermoelectric response data.

Findings

Incoherent Hall conductivity is necessary for correct DC thermal transport.

Application to dyonic black holes determines the incoherent Hall conductivity.

Including this coefficient improves hydrodynamic and AC correlator agreement.

Abstract

We consider magnetohydrodynamics with an external magnetic field. We find that in general one must allow for a non-zero incoherent Hall conductivity to correctly describe the DC longitudinal and Hall thermal conductivities beyond order zero in the magnetic field expansion. We apply our result to the dyonic black hole, determining the incoherent Hall conductivity in that case, and additionally prove that the existence of this transport coefficient leads to a significantly better match between the hydrodynamic and AC thermo-electric correlators.