Increased coherence time in narrowed bath states in quantum dots

TL;DR

This paper investigates how narrowing the nuclear Overhauser field distribution affects electron spin decoherence in quantum dots, using analytic and numerical methods to analyze spin dynamics under various conditions.

Contribution

It introduces a detailed analysis of decoherence in quantum dots considering narrowed bath states, combining analytic solutions and tDMRG simulations for nonuniform couplings.

Findings

Narrowed Overhauser field distributions extend coherence times.

External magnetic fields influence decoherence dynamics.

Analytic and numerical methods agree on key decoherence behaviors.

Abstract

We study the influence of narrowed distributions of the nuclear Overhauser field on the decoherence of a central electron spin in quantum dots. We describe the spin dynamics in quantum dots by the central spin model. We use analytic solutions for uniform couplings and the time dependent density-matrix renormalization group (tDMRG) for nonuniform couplings. With these tools we calculate the dynamics of the central spin for large baths of nuclear spins with or without external magnetic field applied to the central spin. The focus of our study is the influence of initial mixtures with narrowed distributions of the Overhauser field and of applied magnetic fields on the decoherence of the central spin.