Many-body correlations in Floquet steady-states: Frequency-resolved renormalization group of the driven Anderson impurity

TL;DR

This paper develops a frequency-resolved renormalization group method for analyzing driven, interacting quantum systems in steady state, providing insights into dynamical responses and the robustness of many-body correlations like the Kondo effect.

Contribution

It introduces a novel Floquet steady-state functional renormalization group framework that captures frequency-dependent interactions and compares favorably with existing methods.

Findings

Quantitative agreement with Floquet Green's function methods for finite-frequency observables.

Static properties are well approximated by simpler models.

Periodic driving broadens the Kondo resonance but preserves the many-body Kondo cloud.

Abstract

We introduce a functional renormalization group framework formulated directly in the Floquet steady-state that systematically incorporates frequency-dependent interaction effects. By retaining the frequency structure of the two-particle vertex up to second order in interaction strength, our approach provides controlled access to dynamical response functions and nonequilibrium transport in driven, interacting systems. Using the periodically driven single-impurity Anderson model as a paradigmatic example, we benchmark our results against state-of-the-art Floquet Green's function methods and find quantitative agreement for finite-frequency observables up to intermediate interaction strengths. Remarkably, we also show that static properties are often captured reliably by much simpler approximations, suggesting practical pathways for modeling driven quantum materials. Finally, we demonstrate that although periodic driving of the dot strongly broadens the Kondo resonance through inelastic scattering, it leaves the many-body Kondo cloud largely intact. This robustness suppresses Floquet replicas of the Kondo peak and leads to a partial persistence of Kondo pinning, highlighting the resilience of emergent many-body correlations under local periodic driving.