Dynamical decoupling of a singlet-triplet qubit afflicted by a charge fluctuator

@article{Ramon2012DynamicalDO,
  title={Dynamical decoupling of a singlet-triplet qubit afflicted by a charge fluctuator},
  author={Guy Z. Ramon},
  journal={Physical Review B},
  year={2012},
  volume={86},
  pages={125317}
}
  • G. Ramon
  • Published 1 June 2012
  • Physics
  • Physical Review B
The efficiency of dynamical decoupling pulse sequences in removing noise due to a charge fluctuator is studied for a singlet-triplet spin qubit. We develop a numerical method to solve the dynamical equations for all three components of the Bloch vector under a general pulse protocol, and with an arbitrary rotation axis. The qubit is shown to undergo both dephasing and dissipative dynamics, pending on its working point. Analytical solutions are found for the limits of weakly and strongly coupled… 

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References

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Non-rotated Bloch vector components under 11-pulse PDD sequence for working point δh = J (ϕ = π/4). (a) Weakly-coupled fast TLF (1/γ = 0.1µs, v = 2.5 neV), ∆ ∼ γ ≫ v; (b) Weakly

    2 we removed coherent evolution due to the nonzero J and δh

      A more detailed version of Ref. 30 that includes analytical expressions for all coupling terms can be

        Strongly-coupled TLF (1/γ = 0.1 ms, v = 2.5 neV, δh = 0.125µeV ), ∆ ≫ v ≫ γ; (d) Strongly-coupled TLF (1/γ = 0.1 ms, v = 2.5 neV

          A more accurate angular averaging would be to average over the resulting decay rates

            See Fig. 2 in Ref. 30 for qubit-TLF geometry