Voltage quench dynamics of a Kondo system

TL;DR

This paper investigates the real-time dynamics of a quantum dot in the Kondo regime after a sudden bias voltage application, revealing rapid equilibration and temperature-dependent behavior characteristic of Kondo physics.

Contribution

It provides numerically exact simulations of transient current dynamics in a Kondo system following a quantum quench, highlighting observable signatures of Kondo behavior in the time domain.

Findings

Current saturates quickly after bias application.

Saturation temperature aligns with Kondo temperature at small times/voltages.

Enhanced saturation temperature observed outside linear response.

Abstract

We examine the dynamics of a correlated quantum dot in the mixed valence regime. We perform numerically exact calculations of the current after a quantum quench from equilibrium by rapidly applying a bias voltage in a wide range of initial temperatures. The current exhibits short equilibration times and saturates upon the decrease of temperature at all times, indicating Kondo behavior both in the transient regime and in steady state. The time-dependent current saturation temperature matches the Kondo temperature at small times or small voltages; a substantially increased value is observed outside of linear response. These signatures are directly observable by experiments in the time-domain.