Quantum dephasing in a gated GaAs triple quantum dot due to nonergodic noise

TL;DR

This study investigates how non-ergodic environmental noise affects quantum coherence in a GaAs triple quantum dot, revealing multiple dephasing times and noise dynamics on short timescales.

Contribution

It demonstrates the existence of multiple dephasing times in a non-ergodic regime and links them to short-time noise dynamics in a quantum dot system.

Findings

Coherence is boosted in the non-ergodic regime.

Multiple dephasing times depend on phase stability extraction method.

Dephasing times reflect short-time noise dynamics.

Abstract

We extract the phase coherence of a qubit defined by singlet and triplet electronic states in a gated GaAs triple quantum dot, measuring on timescales much shorter than the decorrelation time of the environmental noise. In this non-ergodic regime, we observe that the coherence is boosted and several dephasing times emerge, depending on how the phase stability is extracted. We elucidate their mutual relations, and demonstrate that they reflect the noise short-time dynamics.