title: Designing a practical high-fidelity long-time quantum memory.
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.
authors.affiliation: Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Khodjasteh
authors.forename: Jarrah
authors.initials: J
authors.lastname: Sastrawan
authors.forename: David
authors.initials: D
authors.lastname: Hayes
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Green
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Biercuk
authors.forename: Lorenza
authors.initials: L
authors.lastname: Viola