Effect of Quantum Point Contact Measurement on Electron Spin State in Quantum Dot

TL;DR

This paper investigates how quantum point contact measurements influence electron spin states in quantum dots, revealing measurement-induced decoherence and the quantum Zeno effect in a double quantum-dot system.

Contribution

It demonstrates the impact of QPC measurement on spin state evolution and identifies the quantum Zeno effect in this context.

Findings

QPC measurement induces decoherence in microsecond timescales.

Enhanced measurement traps spin states, demonstrating the quantum Zeno effect.

Measurement affects the stability and evolution of electron spin states.

Abstract

We study the time evolution of two electron spin states in a double quantum-dot system, which includes a nearby quantum point contact (QPC) as a measurement device. We obtain that the QPC measurement induced decoherence is in time scales of microsecond. We also find that the enhanced QPC measurement will trap the system in its initial spin states, which is consistent with quantum Zeno effect.