High-Fidelity Entangling Gate for Double-Quantum-Dot Spin Qubits
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 19, 2017
- Accession Number
- AD1082336
Entities
People
- Amir Yacoby
- Geoffrey C. Gardner
- John M Nichol
- Lucas A. Orona
- Michael J Manfra
- Saeed Fallahi
- Shannon P Harvey
Organizations
- Harvard University