Error in a spin-SWAP gate due to hyperfine interaction in a double quantum dot

ORAL

Abstract

We study the SWAP gate for two exchange-coupled electron spins under the influence of hyperfine (hf) interaction in a double quantum dot. A gate error develops during such a gate because hf interaction causes dephasing between any pair of two-spin states. We find that this gate error is initial-state-dependent. For example, an initial state in the $S_z=0$ subspace suffers only from $S-T_0$ dephasing, leading to smaller gate error than in the case of other initial states. We calculate the gate fidelity for typical initial states, and compare the resulting gate errors. We also analyze the effects of inhomogeneous broadening on the gate fidelity in the presence of a random Overhauser field.

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Authors

  • Jo-Tzu Hung

    Department of Physics, University at Buffalo, State University of New York, University at Buffalo, State University of New York

  • {\L}ukasz Cywi{\'n}ski

    Institute of Physics, Polish Academy of Sciences

  • Xuedong Hu

    University at Buffalo, SUNY, State Univ of NY - Buffalo, Department of Physics, University at Buffalo, State University of New York, University at Buffalo, University at Buffalo, State University of New York, Department of Physics, University at Buffalo, The State University of New York