Protecting collective qubits from non-Markovian dephasing

Fuente: arXiv
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Main Authors: Covolo, Antoine, Magro, Valentin, Girard, Mathieu, Garcia, Sébastien, Ourjoumtsev, Alexei
Format: Preprint
Published: 2025
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author Covolo, Antoine
Magro, Valentin
Girard, Mathieu
Garcia, Sébastien
Ourjoumtsev, Alexei
author_facet Covolo, Antoine
Magro, Valentin
Girard, Mathieu
Garcia, Sébastien
Ourjoumtsev, Alexei
contents Collectively-encoded qubits, involving ensembles of atomic or solid-state emitters, present many practical advantages for quantum technologies. However, they suffer from uncontrolled inhomogeneous dephasing which couples them to a quasi-continuum of dark states. In most cases, this process cannot be encompassed in a standard master equation with time-independent coefficients, making its description either tedious or inaccurate. We show that it can be understood as a displacement in time-frequency phase space and accurately included in resource-efficient numerical simulations of the qubit's dynamics. This description unveils a regime where the qubit becomes protected from dephasing through a combination of strong driving and non-Markovianity. We experimentally investigate this regime using a Rydberg superatom and extend its coherent dynamics beyond the inhomogeneous-dephasing characteristic time by an order of magnitude.
format Preprint
id arxiv_https___arxiv_org_abs_2501_07232
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Protecting collective qubits from non-Markovian dephasing
Covolo, Antoine
Magro, Valentin
Girard, Mathieu
Garcia, Sébastien
Ourjoumtsev, Alexei
Quantum Physics
Atomic Physics
Collectively-encoded qubits, involving ensembles of atomic or solid-state emitters, present many practical advantages for quantum technologies. However, they suffer from uncontrolled inhomogeneous dephasing which couples them to a quasi-continuum of dark states. In most cases, this process cannot be encompassed in a standard master equation with time-independent coefficients, making its description either tedious or inaccurate. We show that it can be understood as a displacement in time-frequency phase space and accurately included in resource-efficient numerical simulations of the qubit's dynamics. This description unveils a regime where the qubit becomes protected from dephasing through a combination of strong driving and non-Markovianity. We experimentally investigate this regime using a Rydberg superatom and extend its coherent dynamics beyond the inhomogeneous-dephasing characteristic time by an order of magnitude.
title Protecting collective qubits from non-Markovian dephasing
topic Quantum Physics
Atomic Physics
url https://arxiv.org/abs/2501.07232