Weak Values of Electron Spin in a Double Quantum Dot

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 (postselection), where the outcome of the first measurement is kept provided a second postselected outcome occurs. The setup 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.Kavli Institute of NanoscienceApplied Science