Dynamical nuclear spin polarization and the Zamboni effect in gated double quantum dots

TL;DR

This paper investigates how a small nuclear spin polarization in gated double quantum dots can significantly prolong singlet decay times by stabilizing Overhauser fields through hyperfine interactions.

Contribution

It introduces a scheme showing that minimal nuclear polarization can dramatically improve quantum dot coherence by stabilizing nuclear reservoirs.

Findings

0.5% nuclear polarization enhances singlet decay time by 100x

Nuclear reservoir equilibration reduces Overhauser field fluctuations

Hyperfine interactions mediate the stabilization process

Abstract

A dynamical nuclear polarization scheme is studied in gated double dots. We demonstrate that a small polarization ($\sim 0.5%$) is sufficient to enhance the singlet decay time by two orders of magnitude. This enhancement is attributed to an equilibration process between the nuclear reservoirs in the two dots accompanied by reduced fluctuations in the Overhauser fields, that are mediated by the electron-nuclear spin hyperfine interaction.