Time scales in the dynamics of an interacting quantum dot

TL;DR

This paper investigates the multiple time scales governing the relaxation dynamics of an interacting quantum dot after a disturbance, revealing a third universal time scale linked to two-particle processes.

Contribution

It identifies and characterizes a third, universal relaxation time scale in the dynamics of an interacting quantum dot, beyond charge and spin relaxation times.

Findings

Three distinct relaxation time scales identified.

The third time scale is independent of level position and Coulomb interaction.

Physical quantities sensitive to two-particle processes reveal this universal time scale.

Abstract

We analyze the dynamics of a single-level quantum dot with Coulomb interaction, weakly tunnel coupled to an electronic reservoir, after it has been brought out of equilibrium, e.g. by a step-pulse potential. We investigate the exponential decay towards the equilibrium state, which is governed by three time scales. In addition to the charge and spin relaxation time there is a third time scale which is independent of the level position and the Coulomb interaction. This time scale emerges in the time evolution of physical quantities sensitive to two-particle processes.