Semi-classical model for the dephasing of a two-electron spin qubit coupled to a coherently evolving nuclear spin bath

TL;DR

This paper introduces a semi-classical model to analyze electron spin decoherence in a two-electron quantum dot caused by hyperfine interactions with nuclear spins, matching experimental echo signals to quantify nuclear spin dynamics.

Contribution

The paper presents a novel semi-classical approach modeling nuclear Overhauser fields as classical vectors to interpret spin-echo experiments.

Findings

Quantifies contributions of Larmor precession and spin diffusion.

Matches model predictions with experimental echo signals.

Provides insights into nuclear spin bath dynamics.

Abstract

We study electron spin decoherence in a two-electron double quantum dot due to the hyperfine interaction, under spin-echo conditions as studied in recent experiments. We develop a semi-classical model for the interaction between the electron and nuclear spins, in which the time-dependent Overhauser fields induced by the nuclear spins are treated as classical vector variables. Comparison of the model with experimentally-obtained echo signals allows us to quantify the contributions of various processes such as coherent Larmor precession and spin diffusion to the nuclear spin evolution.