Floquet-Drude conductivity

TL;DR

This paper develops a comprehensive theoretical framework for calculating the conductivity of periodically driven systems, combining Floquet theory with Green's functions and scattering theory, applicable to materials like graphene.

Contribution

It introduces a fully analytical expression for Floquet-Drude conductivity and generalizes the Floquet Fermi's golden rule for $tt'$-Floquet states, advancing the understanding of driven quantum systems.

Findings

Derived a new analytical formula for Floquet-Drude conductivity.

Connected Floquet Dyson series with scattering theory.

Applicable to systems like graphene and spin-orbit materials.

Abstract

This letter presents a generalization of the Drude conductivity for systems which are exposed to periodic driving. The probe bias is treated perturbatively by using the Kubo formula, whereas the external driving is included non-perturbatively using the Floquet theory. Using a new type of four-times Green's functions disorder is approached diagrammatically, yielding a fully analytical expression for the Floquet-Drude conductivity. Furthermore, the Floquet Fermi's golden rule is generalized to $tt'$-Floquet states, connecting the Floquet-Dyson series with scattering theory for Floquet states. Our formalism allows for a direct application to numerous systems e.g. graphene or spin-orbit systems.