Charge and spin dynamics in interacting quantum dots

TL;DR

This paper investigates the charge and spin dynamics in interacting quantum dots, revealing how Coulomb interactions influence relaxation times after fast switching and during slow harmonic modulation.

Contribution

It introduces a real-time diagrammatic method to analyze both transient and stationary ac responses in strongly interacting quantum dots.

Findings

Charge and spin relaxations are governed by distinct single time constants.

The relaxation times differ from classical RC times due to Coulomb interactions.

The method accurately captures transient and steady-state responses.

Abstract

The transient response of a quantum dot with strong Coulomb interaction to a fast change in the gate potential, as well as the stationary ac-response to a slow harmonic variation of the gate potential are computed by means of a real-time diagrammatic expansion in the tunnel-coupling strength. We find that after a fast switching, the relaxation of charge and spin are governed by a single time constant each, which differ from each other due to Coulomb repulsion. We compare the response to a step potential with the $RC$ time extracted from the ac response.