Accession Number:

AD1082336

Title:

High-Fidelity Entangling Gate for Double-Quantum-Dot Spin Qubits

Descriptive Note:

Journal Article - Open Access

Corporate Author:

Harvard University Cambridge United States

Report Date:

2017-01-19

Pagination or Media Count:

5.0

Abstract:

Electron spins in semiconductors are promising qubits because their long coherence times enable nearly 109 coherent quantum gate operations. However, developing a scalable high-fidelity two-qubit gate remains challenging. Here, we demonstrate an entangling gate between two double-quantum-dot spin qubits in GaAs by using a magnetic field gradient between the two dots in each qubit to suppress decoherence due to charge noise. When the magnetic gradient dominates the voltage-controlled exchange interaction between electrons, qubit coherence times increase by an order of magnitude. Using randomized benchmarking, we measure single-qubit gate fidelities of approximate 99, and through self-consistent quantum measurement, state, and process tomography, we measure an entangling gate fidelity of 90. In the future, operating double quantum dot spin qubits with large gradients in nuclear-spin-free materials, such as Si, should enable a two-qubit gate fidelity surpassing the threshold for fault-tolerant quantum information processing.

Subject Categories:

  • Quantum Theory and Relativity

Distribution Statement:

APPROVED FOR PUBLIC RELEASE