Decoherence and Dynamical Decoupling of Shuttled Spins: towards Modelling of Ge Devices
W. Vermeer (TU Delft - Applied Sciences)
V.V. Dobrovitski – Mentor (TU Delft - QID/Dobrovitski Group)
Yu-Ning Zhang – Mentor
M. Blaauboer – Graduation committee member (TU Delft - QN/Blaauboer Group)
M.F. Russ – Graduation committee member (TU Delft - QCD/Rimbach-Russ)
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Abstract
Shuttling is expected to play a vital role in scaling up quantum computing based on semiconductor spin qubits. Decoherence, caused by interactions between the qubit and its environment, remains a major obstacle to maintaining qubit fidelity. For stationary qubits, decoherence is typically described using standard random processes. However, trajectories such as forth-back shuttling give rise to random processes with nontrivial correlations. We develop and benchmark a numerical method to analyse the effect of 3D random magnetic fields on shuttled spins, particularly relevant to Ge-based devices where the direction of the effective magnetic field varies significantly. Building on this, we design new dynamical decoupling (DD) sequences for shuttling, incorporating a central pulse to suppress the effect of mirror symmetry between the forward and backwards paths. Using realistic parameters for Si and Ge devices with the developed numerical method, we evaluate the effectiveness of DD sequences at suppressing decoherence during shuttling. In particular, we find that the XY8-Z sequence significantly improves fidelity during forth-back shuttling, and outperforms the standard XY8 sequence commonly used for stationary qubits.