Quantum Interference and Coherent Population Trapping\nin a Double Quantum Dot

Quantum\ninterference is a natural consequence of wave-particle\nduality in quantum mechanics, and is widely observed at the atomic\nscale. One interesting manifestation of quantum interference is coherent\npopulation trapping (CPT), first proposed in three-level driven atomic\nsystems and observed in quantum optical experiments. Here, we demonstrate\nCPT in a gate-defined semiconductor double quantum dot (DQD), with\nsome unique twists as compared to the atomic systems. Specifically,\nwe observe CPT in both driven and nondriven situations. We further\nshow that CPT in a driven DQD could be used to generate adiabatic\nstate transfer. Moreover, our experiment reveals a nontrivial modulation\nto the CPT caused by the longitudinal driving field, yielding an odd–even\neffect and a tunable CPT. Our results broaden the field of CPT, and\nopen up the possibility of quantum simulation and quantum computation\nbased on adiabatic passage in quantum dot systems.