Concatenated dynamical decoupling in a solid-state spin bath

TL;DR

This paper evaluates the effectiveness of concatenated dynamical decoupling (CDD) sequences in preserving quantum coherence in solid-state spin qubits within a nuclear spin bath, using a cluster expansion approach.

Contribution

It demonstrates that each CDD level effectively cancels intrabath fluctuations, validating CDD as a practical decoherence mitigation method and challenging previous simplified models.

Findings

Each CDD level reverses intrabath fluctuation effects

Validates CDD as a realistic decoherence control strategy

Challenges previous pair approximation results

Abstract

Concatenated dynamical decoupling (CDD) pulse sequences hold much promise as a strategy to mitigate decoherence in quantum information processing. It is important to investigate the actual performance of these dynamical decoupling strategies in real systems that are promising qubit candidates. In this Rapid Communication, we compute the echo decay of concatenations of the Hahn echo sequence for a solid-state electronic spin qubit in a nuclear spin bath using a cluster expansion technique. We find that each level of concatenation reverses the effect of successive levels of intrabath fluctuations. On the one hand, this advances CDD as a versatile and realistic decoupling strategy. On the other hand, this invalidates, as overly optimistic, results of the simple pair approximation used previously to study restoration, through CDD, of coherence lost to a mesoscopic spin bath.