Long-time Low-latency Quantum Memory by Dynamical Decoupling

TL;DR

This paper demonstrates that periodic high-order dynamical decoupling sequences can create a coherence plateau, enabling long, high-fidelity quantum memory with low latency despite experimental imperfections.

Contribution

It introduces a systematic, experimentally validated approach using dynamical decoupling sequences to achieve long, high-fidelity quantum memory with low access latency.

Findings

Coherence plateau can be engineered with high-order dynamical decoupling.

High-fidelity storage is possible for exceptionally long times.

The approach is robust to experimental imperfections.

Abstract

Quantum memory is a central component for quantum information processing devices, and will be required to provide high-fidelity storage of arbitrary states, long storage times and small access latencies. Despite growing interest in applying physical-layer error-suppression strategies to boost fidelities, it has not previously been possible to meet such competing demands with a single approach. Here we use an experimentally validated theoretical framework to identify periodic repetition of a high-order dynamical decoupling sequence as a systematic strategy to meet these challenges. We provide analytic bounds-validated by numerical calculations-on the characteristics of the relevant control sequences and show that a "stroboscopic saturation" of coherence, or coherence plateau, can be engineered, even in the presence of experimental imperfection. This permits high-fidelity storage for times that can be exceptionally long, meaning that our device-independent results should prove instrumental in producing practically useful quantum technologies.