Full Counting Statistics of Spin Currents

We discuss how to detect fluctuating spin currents and derive full counting statistics of electron spin transfers. We consider several detectors in series monitoring different components of the spins. We have found that in general the statistics of the measurement outcomes cannot be explained with the projection postulate and essentially depends on the quantum dynamics of the detectors.

Figure 1

The proposed spin current detector. An electron with velocity $\mathbf{v}$ and spin $\mathbf{S}$ induces a voltage drop in a capacitor. The electric field $\mathbf{E}$ inside the capacitor produces an Aharonov-Casher phase shift on the electrons.

Figure 2

The setup considered, in the case of three spin detectors and one charge detector.