A Non-Demolition Single Spin Meter

TL;DR

This paper proposes a quantum dot-based method for non-demolition single spin measurement using microwave-induced resonance, enabling sensitive detection of local magnetic fields and spin states without destroying the spin.

Contribution

It introduces a theoretical framework for a non-demolition single spin meter utilizing a quantum dot under microwave irradiation and charge detection, with conditions for reliable spin readout.

Findings

Resonant microwave irradiation changes the quantum dot occupation.

The Rabi frequency determines the resonance width.

Non-demolition readout is possible with different g-factors.

Abstract

We present the theory of a single spin meter consisting of a quantum dot in a magnetic field under microwave irradiation combined with a charge counter. We show that when a current is passed through the dot, a change in the average occupation number occurs if the microwaves are resonant with the on-dot Zeeman splitting. The width of the resonant change is given by the microwave induced Rabi frequency, making the quantum dot a sensitive probe of the local magnetic field and enabling the detection of the state of a nearby spin. If the dot-spin and the nearby spin have different g-factors a non-demolition readout of the spin state can be achieved. The conditions for a reliable spin readout are found.