Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1604.03293 · Physical Review A

Dynamical zeroing of spin-wave momentum to suppress motional dephasing in an atomic-ensemble quantum memory

Yan Jiang, Jun Rui, Xiao‐Hui Bao, Jian-Wei Pan

Published Jun 10, 2016• 28 citations
arXivHTMLPDF

Abstract

Atomic motion plays a detrimental role in atom-gas quantum memories. To circumvent the problem, a ``freezing'' pulse technique is experimentally investigated, demonstrating extended storage time and unrestricted detection angle.
DOI
10.1103/physreva.93.063819

Related papers

Operating Spin Echo in the Quantum Regime for an Atomic-Ensemble Quantum Memory

Jun Rui, Yan Jiang, Sheng-Jun Yang +3 more

Spin echo is a powerful technique to extend atomic or nuclear coherence times by overcoming the dephasing due to inhomogeneous broadenings. However, there are disputes about the feasibility of applying this technique to an ensemble-based quantum memory at the single-quanta level. In this experimental study, we find that noise due to imperfections of the rephasing pulses has both intense superradiant and weak isotropic parts. By properly arranging the beam directions and optimizing the pulse fidelities, we successfully manage to operate the spin echo technique in the quantum regime by observing nonclassical photon-photon correlations as well as the quantum behavior of retrieved photons. Our work for the first time demonstrates the feasibility of harnessing the spin echo method to extend the lifetime of ensemble-based quantum memories at the single-quanta level.

arXiv:1501.06278•Physical Review Letters•Sep 24, 2015•35 citations

Freezing motion-induced dephasing for single spin-state stored in atomic ensemble

Yan Jiang, Jun Rui, Xiao‐Hui Bao +1 more

Bulletin of the American Physical Society•May 25, 2016•0 citations

Continuous Protection of a Collective State from Inhomogeneous Dephasing

R. Finkelstein, O. Lahad, I. Cohen +4 more

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, higherorder 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 memories with 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.

arXiv:2004.02295•Physical Review X•Jan 13, 2021•26 citations

Ultralong Dephasing Times in Solid-State Spin Ensembles via Quantum Control

Erik Bauch, Connor A. Hart, Jennifer M. Schloss +5 more

New techniques reduce the spin dephasing time in nitrogen-vacancy centers by more than an order of magnitude, greatly decreasing the time needed for magnetic field sensing and possibly opening up this quantum sensing technology to much broader applications.

arXiv:1801.03793•Physical Review X•Jul 25, 2018•187 citations

Motional dephasing of atomic clock spin waves in an optical lattice

S. D. Jenkins, T Zhang, T. A. B. Kennedy

In a cold atomic ensemble the weak Raman scattering of an incident laser beam writes a spin-wave grating by transferring an atom between ground-level hyperfine states. These spin-waves serve as a basis for a quantum memory. For clock states, where magnetic dephasing is suppressed, thermal motion of the atoms across the spin-wave is the principal source of dephasing on the sub-millisecond timescale, limiting the quantum memory time achievable. An investigation of the role of the optical lattice in reducing motional dephasing is presented, using Monte Carlo simulations to study the influence of ensemble temperature, trap depth and differential ac Stark shifts in the case of rubidium.

Journal of Physics B Atomic Molecular and Optical Physics•Jun 8, 2012•24 citations

Noise in optical quantum memories based on dynamical decoupling of spin states

Emmanuel Zambrini Cruzeiro, Florian Fröwis, Nuala Timoney +1 more

Long-lived optical quantum memories are of great importance for scalable distribution of entanglement over remote networks (e.g. quantum repeaters). Long-lived storage generally relies on storing the optical states as spin excitations since these often exhibit long coherence times. To extend the storage time beyond the intrinsic spin dephasing time one can use dynamical decoupling techniques. However, it has been shown that dynamical decoupling introduces noise in optical quantum memories based on ensembles of atoms. In this article, a simple model is proposed to calculate the resulting signal-to-noise ratio, based on intrinsic quantum memory parameters such as the optical depth of the ensemble. We also characterize several dynamical decoupling sequences that are efficient in reducing this particular noise. Our calculations indicate that it should be feasible to reach storage times well beyond one second under reasonable experimental conditions.

arXiv:1512.05658•Journal of Modern Optics•Jul 7, 2016•12 citations
Spin echo is a powerful technique to extend atomic or nuclear coherence times by overcoming the dephasing due to inhomogeneous broadenings. However, there are disputes about the feasibility of applying this technique to an ensemble-based quantum memory at the single-quanta level. In this experimental study, we find that noise due to imperfections of the rephasing pulses has both intense superradiant and weak isotropic parts. By properly arranging the beam directions and optimizing the pulse fidelities, we successfully manage to operate the spin echo technique in the quantum regime by observing nonclassical photon-photon correlations as well as the quantum behavior of retrieved photons. Our work for the first time demonstrates the feasibility of harnessing the spin echo method to extend the lifetime of ensemble-based quantum memories at the single-quanta level.
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, higherorder 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 memories with 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.
In a cold atomic ensemble the weak Raman scattering of an incident laser beam writes a spin-wave grating by transferring an atom between ground-level hyperfine states. These spin-waves serve as a basis for a quantum memory. For clock states, where magnetic dephasing is suppressed, thermal motion of the atoms across the spin-wave is the principal source of dephasing on the sub-millisecond timescale, limiting the quantum memory time achievable. An investigation of the role of the optical lattice in reducing motional dephasing is presented, using Monte Carlo simulations to study the influence of ensemble temperature, trap depth and differential ac Stark shifts in the case of rubidium.
Long-lived optical quantum memories are of great importance for scalable distribution of entanglement over remote networks (e.g. quantum repeaters). Long-lived storage generally relies on storing the optical states as spin excitations since these often exhibit long coherence times. To extend the storage time beyond the intrinsic spin dephasing time one can use dynamical decoupling techniques. However, it has been shown that dynamical decoupling introduces noise in optical quantum memories based on ensembles of atoms. In this article, a simple model is proposed to calculate the resulting signal-to-noise ratio, based on intrinsic quantum memory parameters such as the optical depth of the ensemble. We also characterize several dynamical decoupling sequences that are efficient in reducing this particular noise. Our calculations indicate that it should be feasible to reach storage times well beyond one second under reasonable experimental conditions.