Concatenated dynamical decoupling with virtual pulses

TL;DR

This paper introduces vCDD, an improved dynamical decoupling scheme for quantum systems that uses virtual pulses to reduce power and enhance robustness against imperfections, advancing quantum decoherence mitigation.

Contribution

The paper proposes vCDD, a novel dynamical decoupling method that replaces some physical pulses with virtual ones, improving robustness and reducing power deposition.

Findings

vCDD outperforms traditional CDD in robustness against pulse errors.

vCDD requires less power due to virtual pulses.

The scheme enhances quantum coherence preservation.

Abstract

The loss of quantum information due to interaction with external degrees of freedom, which is known as decoherence, remains one of the main obstacles for large-scale implementations of quantum computing. Accordingly, different measures are being explored for reducing its effect. One of them is dynamical decoupling (DD) which offers a practical solution because it only requires the application of control pulses to the system qubits. Starting from basic DD sequences, more sophisticated schemes were developed that eliminate higher-order terms of the system-environment interaction and are also more robust against experimental imperfections. A particularly successful scheme, called concatenated DD (CDD), gives a recipe for generating higher order sequences by inserting lower order sequences into the delays of a generating sequence. Here, we show how this scheme can be improved further by converting some of the pulses to virtual (and thus ideal) pulses. The resulting scheme, called vCDD, has lower power deposition and is more robust against pulse imperfections than the original CDD scheme.