Tunable Hybrid Qubit in a GaAs Double Quantum Dot

Gang Cao, Hai-Ou Li, Guo-Dong Yu, Bao-Chuan Wang, Bao-Bao Chen, Xiang-Xiang Song, Ming Xiao, Guang-Can Guo, Hong-Wen Jiang, Xuedong Hu, and Guo-Ping Guo

Phys. Rev. Lett. 116, 086801 – Published 25 February 2016

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.

Received 4 October 2015

DOI:https://doi.org/10.1103/PhysRevLett.116.086801

Physics Subject Headings (PhySH)

Quantum information with solid state qubits

Double quantum dots Heterostructures

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Gang Cao^1,2, Hai-Ou Li^1,2, Guo-Dong Yu^1,2, Bao-Chuan Wang^1,2, Bao-Bao Chen^1,2, Xiang-Xiang Song^1,2, Ming Xiao^1,2,*, Guang-Can Guo^1,2, Hong-Wen Jiang³, Xuedong Hu⁴, and Guo-Ping Guo^1,2,†

¹Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
²Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
³Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095, USA
⁴Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, USA