Quantum Coherence in a One-Electron Semiconductor Charge Qubit

TL;DR

This paper investigates quantum coherence in a GaAs-based single-electron charge qubit, demonstrating a maximum coherence time of approximately 7 nanoseconds and analyzing noise effects on coherence.

Contribution

It provides the first detailed measurement of coherence times in a semiconductor charge qubit and compares experimental results with a 1/f noise model.

Findings

Maximum coherence time of ~7 ns at charge degeneracy point

Coherence time is sensitive to gate voltage fluctuations

Experimental data aligns with 1/f noise predictions

Abstract

We study quantum coherence in a semiconductor charge qubit formed from a GaAs double quantum dot containing a single electron. Voltage pulses are applied to depletion gates to drive qubit rotations and non-invasive state readout is achieved using a quantum point contact charge detector. We measure a maximum coherence time of ~7 ns at the charge degeneracy point, where the qubit level splitting is first-order-insensitive to gate voltage fluctuations. We compare measurements of the coherence time as a function of detuning with predictions from a 1/f noise model.