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

  title={Dynamical decoupling of a singlet-triplet qubit afflicted by a charge fluctuator},
  author={Guy Z. Ramon},
  journal={Physical Review B},
  • 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… 

Environmental noise spectroscopy with qubits subjected to dynamical decoupling

A qubit subjected to pure dephasing due to classical Gaussian noise can be turned into a spectrometer of this noise by utilizing its readout under properly chosen dynamical decoupling (DD) sequences

Qubit decoherence under two-axis coupling to low-frequency noises

Many solid-state qubit systems are afflicted by low frequency noise mechanisms that operate along two perpendicular axes of the Bloch sphere. Depending on the qubit’s control fields, either noise can

Spectroscopy of cross correlations of environmental noises with two qubits

A single qubit driven by an appropriate sequence of control pulses can serve as a spectrometer of local noise affecting its energy splitting. We show that by driving and observing two spatially

How to detect qubit-environment entanglement generated during qubit dephasing

We propose a straightforward experimental protocol to test whether qubit-environment entanglement is generated during pure dephasing of a qubit. The protocol is implemented using only measurements

Trispectrum reconstruction of non-Gaussian noise

Using a qubit to probe non-Gaussian noise environments is theoretically studied in the context of classical random telegraph processes. Protocols for control pulses are developed to effectively scan

Adiabatic electron charge transfer between two quantum dots in presence of 1/f noise

Controlled transfer of a single electron through a chain of quantum dots has been recently achieved in GaAs and Si/SiGe based quantum dots, opening prospects for turning stationary spin qubits into

Phase shift of electron spin echo signal caused by polarization of nuclear spins: revealing the quantum nature of spin environment

We consider the spin echo decay of a nitrogen-vacancy center spin qubit, based on $m\! =\! 0$ and $m\! =\! 1$ levels of the $S\!= \! 1$ ground state spin manifold of the center, in presence of finite

Influence of nuclear spin polarization on the spin-echo signal of an NV-center qubit

We consider the spin echo dynamics of a nitrogen-vacancy center qubit based the $S\!= \! 1$ ground state spin manifold, caused by a dynamically polarized nuclear environment. We show that the echo

Measuring trajectories of environmental noise

In classical mechanics, a natural way to simplify a many-body problem is to “replace” some of the elements of the composite system with surrogate force fields. In the realm of quantum mechanics,



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