Two-qubit couplings of singlet-triplet qubits mediated by one quantum state

Sebastian Mehl, Hendrik Bluhm, and David P. DiVincenzo
Phys. Rev. B 90, 045404 – Published 9 July 2014

Abstract

We describe high-fidelity entangling gates between singlet-triplet qubits (STQs) which are coupled via one quantum state (QS). The QS can be provided by a quantum dot itself or by another confined system. The orbital energies of the QS are tunable using an electric gate close to the QS, which changes the interactions between the STQs independent of their single-qubit parameters. Short gating sequences exist for controlled not (cnot) operations. We show that realistic quantum dot setups permit excellent entangling operations with gate infidelities below 103, which is lower than the quantum error correction threshold of the surface code. We consider limitations from fabrication errors, hyperfine interactions, spin-orbit interactions, and charge noise in GaAs and Si heterostructures.

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  • Received 28 March 2014
  • Revised 16 June 2014

DOI:https://doi.org/10.1103/PhysRevB.90.045404

©2014 American Physical Society

Authors & Affiliations

Sebastian Mehl1,2,*, Hendrik Bluhm2, and David P. DiVincenzo1,2

  • 1Peter Grünberg Institute (PGI-2), Forschungszentrum Jülich, D-52425 Jülich, Germany
  • 2JARA-Institute for Quantum Information, RWTH Aachen University, D-52056 Aachen, Germany

  • *s.mehl@fz-juelich.de

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Issue

Vol. 90, Iss. 4 — 15 July 2014

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