Weak values of electron spin in a double quantum dot

TL;DR

This paper proposes an experimental protocol to measure weak values of electron spin in a double quantum dot, predicting anomalously large and negative spin values, and discusses decoherence effects.

Contribution

It introduces a novel protocol for measuring weak values in solid state devices using a double quantum dot and quantum point contact.

Findings

Prediction of anomalously large spin values

Observation of negative total spin values

Incorporation of decoherence effects

Abstract

We propose a protocol for a controlled experiment to measure a weak value of the electron's spin in a solid state device. The weak value is obtained by a two step procedure -- weak measurement followed by a strong one (post-selection), where the outcome of the first measurement is kept provided a second post-selected outcome occurs. The set-up consists of a double quantum dot and a weakly coupled quantum point contact to be used as a detector. Anomalously large values of the spin of a two electron system are predicted, as well as negative values of the total spin. We also show how to incorporate the adverse effect of decoherence into this procedure.