Holographic Floquet states in low dimensions (I)

TL;DR

This paper investigates holographic (2+1)-dimensional gauge theories under rotating electric fields, revealing non-equilibrium phases, resonance phenomena, and photovoltaic Hall effects, with implications for universality in driven strongly coupled systems.

Contribution

It introduces a holographic model of Floquet states in low dimensions, demonstrating phase behavior, resonance effects, and Hall phenomena in a strongly coupled gauge theory.

Findings

Identification of conductive and insulator phases under rotation

Resonance with vector mesons induces rotating currents at specific frequencies

Observation of photovoltaic Hall effect in massive charged carriers

Abstract

We study the response of a (2+1)-dimensional gauge theory to an external rotating electric field. In the strong coupling regime such system is formulated holographically in a top-down model constructed by intersecting D3- and D5-branes along 2+1 dimensions, in the quenched approximation, in which the D5-brane is a probe in the AdS_5 x S^5 geometry. The system has a non-equilibrium phase diagram with conductive and insulator phases. The external driving induces a rotating current due to vacuum polarization (in the insulator phase) and to Schwinger effect (in the conductive phase). For some particular values of the driving frequency the external field resonates with the vector mesons of the model and a rotating current can be produced even in the limit of vanishing driving field. These features are in common with the (3+1) dimensional setup based on the D3-D7 brane model and hint on some interesting universality. We also compute the conductivities paying special attention to the photovoltaic induced Hall effect, which is only present for massive charged carriers. In the vicinity of the Floquet condensate the optical Hall coefficient persists at zero driving field, signalling time reversal symmetry breaking.