Electrical measurement of a two-electron spin state in a double quantum dot

TL;DR

This paper proposes an electrical measurement scheme for two-electron spin states in a double quantum dot, utilizing adiabatic charge transfer influenced by spin-orbit coupling to identify quantum superpositions.

Contribution

It introduces a novel method to electrically detect two-electron spin states by analyzing charge transfer affected by spin-orbit interactions in quantum dots.

Findings

Charge transfer reflects spin state and phase information

Spin-orbit coupling enables spin state detection via charge measurement

Method allows precise identification of quantum superpositions

Abstract

We propose a scheme for electrical measurement of two-electron spin states in a semiconductor double quantum dot. We calculated the adiabatic charge transfer when surface gates are modulated in time. Because of spin-orbit coupling in the semiconductor, spatial displacement of the electrons causes a total spin rotation. It follows that the expectation value of the transferred charge reflects the relative phase as well as the total spin population of a prepared singlet-triplet superposition state. The precise detection of the charge transfer serves to identify the quantum superposition.