Fast spin state preparation in a single charged quantum dot

ORAL

Abstract

Electron spins trapped inside of semiconductor dots (QD) are promising candidates for quantum bits (qubits). Quantum computation requires both the initialization of qubits with a high fidelity and a continuous supply of fresh ancillary qubits. The latter is the key for quantum error correction (QEC). Here, we demonstrate fast spin state preparation (laser cooling of an electron spin) in a single charged InAs self-assembled QD by applying magnetic field in the Voigt geometry. The preparation efficiency of the spin state is 98.9{\%} at a magnetic field of 0.88T, which corresponds to the cooling of spin from 5 K (experimental temperature) to 0.06 K. To reach the same efficiency by thermal equilibration, a 69 T static magnetic field should be applied. The spin cooling rate of $3\cdot 8\times 10^9s^{-1}$ is achieved. This is three orders of magnitude faster than the spin decoherence rate, which is on the order of$1\times 10^6s^{-1}$.

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Authors

  • Xiaodong Xu

    H. M. Randall Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA, The H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109

  • Yanwen Wu

    University of Michigan, H. M. Randall Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA, The H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109

  • Bo Sun

    H. M. Randall Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA

  • Jun Cheng

    H. M. Randall Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA, The H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109

  • Qiong Huang

    H. M. Randall Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA

  • Duncan Steel

    University of Michigan, H. M. Randall Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA, The H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109

  • Allan Bracker

    Naval Research Laboratory, Washington DC 20375

  • Dan Gammon

    Naval Research Laboratory, Washington DC 20375, The Naval Research Laboratory, Washington D.C. 20375

  • Clive Emary

    Department of Physics, The University of California, San-Diego,La Jolla, California 92093

  • L.J. Sham

    University of California, San Diego, University of California San Diego, Department of Physics, The University of California, San-Diego,La Jolla, California 92093, Department of Physics, University of California, San Diego, La Jolla, California, 92093-0319