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.
@article{arxiv.0907.4191,
title = {Electrical measurement of a two-electron spin state in a double quantum dot},
author = {Nobuhiko Yokoshi and Hiroshi Imamura and Hideo Kosaka},
journal= {arXiv preprint arXiv:0907.4191},
year = {2009}
}