Quantum Interference and Coherent Population Trapping in a Double Quantum Dot

TL;DR

This paper demonstrates coherent population trapping (CPT) in a double quantum dot system, revealing unique driven and non-driven CPT phenomena, and explores its potential for adiabatic state transfer and tunable quantum control.

Contribution

It reports the first observation of CPT in a semiconductor double quantum dot, including driven and non-driven cases, with novel modulation effects and applications for quantum state transfer.

Findings

CPT observed in both driven and non-driven double quantum dots

Identification of a non-trivial modulation effect on CPT due to driving fields

Potential for adiabatic state transfer using CPT in quantum dots

Abstract

Quantum interference is a natural consequence of wave-particle duality in quantum mechanics, and is widely observed at the atomic scale. One interesting manifestation of quantum interference is coherent population trapping (CPT), first proposed in three-level driven atomic systems and observed in quantum optical experiments. Here, we demonstrate CPT in a gate-defined semiconductor double quantum dot (DQD), with some unique twists as compared to the atomic systems. Specifically, we observe CPT in both driven and non-driven situations. We further show that CPT in a driven DQD could be used to generate adiabatic state transfer. Moreover, our experiment reveals a non-trivial modulation to the CPT caused by the longitudinal driving field, yielding an odd-even effect and a tunable CPT.