Continuous Protection of a Collective State from Inhomogeneous Dephasing

R. Finkelstein, O. Lahad, I. Cohen, O. Davidson, S. Kiriati, E. Poem, O. Firstenberg

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

We introduce and demonstrate a scheme for eliminating the inhomogeneous dephasing of a collective quantum state. The scheme employs off-resonant fields that continuously dress the collective state with an auxiliary sensor state, which has an enhanced and opposite sensitivity to the same source of inhomogeneity. We derive the optimal conditions under which the dressed state is fully protected from dephasing when using either one or two dressing fields. The latter provides better protection, circumvents qubit phase rotation, and suppresses the sensitivity to drive noise. We further derive expressions for all residual, higher-order sensitivities. We experimentally study the scheme by protecting a collective excitation of an atomic ensemble, where inhomogeneous dephasing originates from thermal motion. Using photon storage and retrieval, we demonstrate complete suppression of inhomogeneous dephasing and, consequently, a prolonged memory time. Our scheme may be applied to eliminate motional dephasing in other systems, improving the performance of quantum gates and memorieswith neutral atoms. It is also generally applicable to various gas, solid, and engineered systems, where sensitivity to variations in time, space, or other domains limits possible scale-up of the system.

Original languageEnglish
Article number011008
JournalPhysical Review X
Volume11
Issue number1
DOIs
StatePublished - 13 Jan 2021
Externally publishedYes

Funding

FundersFunder number
BSF-NSF
Federal German Ministry for Education and Research
iCore
Laboratory in Memory of Leon
Marie Skodowska-Curie
Horizon 2020 Framework Programme678674, 785902
European Research Council
Minerva Foundation
Israel Science Foundation
PAZY Foundation

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