Robust, long-lived optical quantum memories are important components of many quantum information and communication protocols. We demonstrate coherent generation, storage, and retrieval of excitations on a long-lived spin transition via spontaneous Raman scattering in a rare-earth ion-doped crystal. We further study the time dynamics of the optical correlations in this system. This is the first demonstration of its kind in a solid and an enabling step toward realizing a solid-state quantum repeater.Robust, long-lived optical quantum memories are important components of many quantum information and communication protocols. We demonstrate coherent generation, storage, and retrieval of excitations on a long-lived spin transition via spontaneous Raman scattering in a rare-earth ion-doped crystal. We further study the time dynamics of the optical correlations in this system. This is the first demonstration of its kind in a solid and an enabling step toward realizing a solid-state quantum repeater.

Optics ExpressApr 16, 201311 citations

Long-lived quantum coherences in a V -type system strongly driven by a thermal environment

Suyesh Koyu, Timur V. Tscherbul

We explore the coherent dynamics of a three-level $\mathsf{V}$ -type system interacting with a thermal bath in the regime where thermal excitation occurs much faster than spontaneous decay. We present analytic solutions of the Bloch-Redfield quantum master equations, which show that strong incoherent pumping can generate long-lived quantum coherences among the excited states of the $\mathsf{V}$ -type system in the overdamped regime defined by the condition $\mathrm{\ensuremath{\Delta}}/(\overline{n}\ensuremath{\gamma})<f(p)$, where $\mathrm{\ensuremath{\Delta}}$ is the excited-state level splitting, $\ensuremath{\gamma}$ is the spontaneous decay rate, $\overline{n}\ensuremath{\gg}1$ is the effective photon occupation number proportional to the pumping intensity, and $f(p)$ is a universal function of the transition dipole alignment parameter $p$ . In the limit of nearly parallel transition dipoles ($p\ensuremath{\rightarrow}1$) the coherence lifetime ${\ensuremath{\tau}}_{c}=1.34(\overline{n}/\ensuremath{\gamma}){(\mathrm{\ensuremath{\Delta}}/\ensuremath{\gamma})}^{\ensuremath{-}2}$ scales linearly with $\overline{n}$ and is enhanced by the factor $0.67\overline{n}$ with respect to the weak-pumping limit [Phys. Rev. Lett. 113, 113601 (2014); J. Chem. Phys. 144, 244108 (2016)]. We also establish the existence of long-lived quasistationary states, which occur in the overdamped regime and affect the process of thermalization of the $\mathsf{V}$ -type system with the bath, slowing down the approach to thermal equilibrium. In the case of nonparallel transition dipole moments ( $p<1$ ), no quasistationary states are formed and the coherence lifetime decreases sharply. The sharp transition between the different regimes of coherent dynamics is due to an interplay between coherence-generating Fano interference and various coherence-destroying processes (such as stimulated decay). Using a newly developed effective decoherence rate model, we find that in the limit $p\ensuremath{\rightarrow}1$ the rates of coherence generation and decay are almost exactly balanced and the effective decoherence rate is minimized, leading to long coherence lifetimes. Our results reveal new regimes of long-lived quantum coherent dynamics, which could be observed in thermally driven atomic and molecular systems.We explore the coherent dynamics of a three-level $\mathsf{V}$-type system interacting with a thermal bath in the regime where thermal excitation occurs much faster than spontaneous decay. We present analytic solutions of the Bloch-Redfield quantum master equations, which show that strong incoherent pumping can generate long-lived quantum coherences among the excited states of the $\mathsf{V}$-type system in the overdamped regime defined by the condition $\mathrm{\ensuremath{\Delta}}/(\overline{n}\ensuremath{\gamma})<f(p)$, where $\mathrm{\ensuremath{\Delta}}$ is the excited-state level splitting, $\ensuremath{\gamma}$ is the spontaneous decay rate, $\overline{n}\ensuremath{\gg}1$ is the effective photon occupation number proportional to the pumping intensity, and $f(p)$ is a universal function of the transition dipole alignment parameter $p$. In the limit of nearly parallel transition dipoles ($p\ensuremath{\rightarrow}1$) the coherence lifetime ${\ensuremath{\tau}}_{c}=1.34(\overline{n}/\ensuremath{\gamma}){(\mathrm{\ensuremath{\Delta}}/\ensuremath{\gamma})}^{\ensuremath{-}2}$ scales linearly with $\overline{n}$ and is enhanced by the factor $0.67\overline{n}$ with respect to the weak-pumping limit [Phys. Rev. Lett. 113, 113601 (2014); J. Chem. Phys. 144, 244108 (2016)]. We also establish the existence of long-lived quasistationary states, which occur in the overdamped regime and affect the process of thermalization of the $\mathsf{V}$-type system with the bath, slowing down the approach to thermal equilibrium. In the case of nonparallel transition dipole moments ($p<1$), no quasistationary states are formed and the coherence lifetime decreases sharply. The sharp transition between the different regimes of coherent dynamics is due to an interplay between coherence-generating Fano interference and various coherence-destroying processes (such as stimulated decay). Using a newly developed effective decoherence rate model, we find that in the limit $p\ensuremath{\rightarrow}1$ the rates of coherence generation and decay are almost exactly balanced and the effective decoherence rate is minimized, leading to long coherence lifetimes. Our results reveal new regimes of long-lived quantum coherent dynamics, which could be observed in thermally driven atomic and molecular systems.

arXiv:1712.04625Physical Review AAug 7, 201819 citations

Selecting Excited States

Anonymous

FocusJun 1, 19991 citation

Method of Direct Detection and Investigation of Long-Lived Excited States of Singly and Multiply Charged Ions of Transition and Rare-Earth Metals

Sergey F. Belykh, А. Б. Толстогузов, Anatoly Bekkerman +1 more

A method has been proposed for the direct detection and study of long-lived excited states of singly and multiply charged ions of transition and rare earth metals. It allows both the measurement of the photon spectra from the decay of long-lived states of ions with a given charge, as well as the lifetimes of such states, and the investigation of the influence of an electric field on the characteristics of long-lived states. The fast electric-field-induced decay of long-lived states has been found for the first time.A method has been proposed for the direct detection and study of long-lived excited states of singly and multiply charged ions of transition and rare earth metals. It allows both the measurement of the photon spectra from the decay of long-lived states of ions with a given charge, as well as the lifetimes of such states, and the investigation of the influence of an electric field on the characteristics of long-lived states. The fast electric-field-induced decay of long-lived states has been found for the first time.

Journal of Experimental and Theoretical Physics LettersApr 1, 20191 citation

Excited States

Giampaolo Co’

UNITEXT for physicsJan 1, 20260 citations

We explore the coherent dynamics of a three-level

\mathsf{V}

-type system interacting with a thermal bath in the regime where thermal excitation occurs much faster than spontaneous decay. We present analytic solutions of the Bloch-Redfield quantum master equations, which show that strong incoherent pumping can generate long-lived quantum coherences among the excited states of the

\mathsf{V}

-type system in the overdamped regime defined by the condition $\mathrm{\ensuremath{\Delta}}/(\overline{n}\ensuremath{\gamma})<f(p)$, where $\mathrm{\ensuremath{\Delta}}$ is the excited-state level splitting, $\ensuremath{\gamma}$ is the spontaneous decay rate, $\overline{n}\ensuremath{\gg}1$ is the effective photon occupation number proportional to the pumping intensity, and

f(p)

is a universal function of the transition dipole alignment parameter

p

. In the limit of nearly parallel transition dipoles ($p\ensuremath{\rightarrow}1$) the coherence lifetime ${\ensuremath{\tau}}_{c}=1.34(\overline{n}/\ensuremath{\gamma}){(\mathrm{\ensuremath{\Delta}}/\ensuremath{\gamma})}^{\ensuremath{-}2}$ scales linearly with

\overline{n}

and is enhanced by the factor

0.67\overline{n}

with respect to the weak-pumping limit [Phys. Rev. Lett. 113, 113601 (2014); J. Chem. Phys. 144, 244108 (2016)]. We also establish the existence of long-lived quasistationary states, which occur in the overdamped regime and affect the process of thermalization of the

\mathsf{V}

-type system with the bath, slowing down the approach to thermal equilibrium. In the case of nonparallel transition dipole moments (

p<1

), no quasistationary states are formed and the coherence lifetime decreases sharply. The sharp transition between the different regimes of coherent dynamics is due to an interplay between coherence-generating Fano interference and various coherence-destroying processes (such as stimulated decay). Using a newly developed effective decoherence rate model, we find that in the limit $p\ensuremath{\rightarrow}1$ the rates of coherence generation and decay are almost exactly balanced and the effective decoherence rate is minimized, leading to long coherence lifetimes. Our results reveal new regimes of long-lived quantum coherent dynamics, which could be observed in thermally driven atomic and molecular systems.