Protected quantum computing: Interleaving gate operations with dynamical decoupling sequences

TL;DR

This paper introduces a method to integrate dynamical decoupling with quantum gate operations, significantly improving fidelity in noisy quantum systems, demonstrated on nitrogen-vacancy centers in diamond.

Contribution

It presents a general scheme for combining dynamical decoupling with quantum gates, achieving high fidelity in a practical quantum system.

Findings

Process fidelities >98% achieved

Gate times 100 times longer than dephasing time

Effective noise suppression during quantum operations

Abstract

Implementing precise operations on quantum systems is one of the biggest challenges for building quantum devices in a noisy environment. Dynamical decoupling (DD) attenuates the destructive effect of the environmental noise, but so far it has been used primarily in the context of quantum memories. Here, we present a general scheme for combining DD with quantum logical gate operations and demonstrate its performance on the example of an electron spin qubit of a single nitrogen-vacancy center in diamond. We achieve process fidelities >98% for gate times that are 2 orders of magnitude longer than the unprotected dephasing time $T_{2}$.