Optical measurement of electron spins in quantum dots: Quantum Zeno effects

TL;DR

This paper investigates how continuous optical measurement influences electron spins in quantum dots, demonstrating quantum Zeno and anti-Zeno effects that can suppress or accelerate nuclear-induced spin relaxation.

Contribution

It provides a microscopic theoretical analysis of quantum back action effects on electron spins under optical measurement, highlighting controllable spin relaxation dynamics.

Findings

Quantum Zeno effect can suppress spin relaxation.

Quantum anti-Zeno effect can accelerate spin relaxation.

Theoretical predictions are testable in future experiments.

Abstract

We describe the effects of the quantum back action under continuous optical measurement of electron spins in quantum dots. We consider the system excitation by elliptically polarized light close to the trion resonance, which allows for the simultaneous spin orientation and measurement. We microscopically demonstrate that the nuclei-induced spin relaxation can be both suppressed and accelerated by the continuous spin measurement due to the quantum Zeno and anti-Zeno effects, respectively. Our theoretical predictions can be directly compared with the future experimental results and straightforwardly generalized for the pump-probe experiments.