Quadrupolar Exchange-Only Spin Qubit.

  title={Quadrupolar Exchange-Only Spin Qubit.},
  author={Maximilian Russ and Jason R. Petta and Guido Burkard},
  journal={Physical review letters},
  volume={121 17},
We propose a quadrupolar exchange-only spin qubit that is highly robust against charge noise and nuclear spin dephasing, the dominant decoherence mechanisms in quantum dots. The qubit consists of four electrons trapped in three quantum dots, and operates in a decoherence-free subspace to mitigate dephasing due to nuclear spins. To reduce sensitivity to charge noise, the qubit can be completely operated at an extended charge noise sweet spot that is first-order insensitive to electrical… 

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