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arXiv:1510.00895 · Physical Review Letters

Tunable Hybrid Qubit in a GaAs Double Quantum Dot

Gang Cao, Hai-Ou Li, Guodong Yu, Bao‐Chuan Wang, Bao-Bao Chen, Xiang‐Xiang Song, Ming Xiao, Guang‐Can Guo, H. W. Jiang, Xuedong Hu, Guo‐Ping Guo

Published Feb 25, 2016• 87 citations
arXivHTMLPDF

Abstract

We experimentally demonstrate a tunable hybrid qubit in a five-electron GaAs double quantum dot. The qubit is encoded in the (1,4) charge regime of the double dot and can be manipulated completely electrically. More importantly, dot anharmonicity leads to quasiparallel energy levels and a new anticrossing, which help preserve quantum coherence of the qubit and yield a useful working point. We have performed Larmor precession and Ramsey fringe experiments near the new working point and find that the qubit decoherence time is significantly improved over a charge qubit. This work shows a new way to encode a semiconductor qubit that is controllable and coherent.

DOI
10.1103/physrevlett.116.086801

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