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:quant-ph/0210189 · Physical Review Letters

Quasi-Spin-Wave Quantum Memories with a Dynamical Symmetry

C. P. Sun, Yahui Li, Xingfang Liu

Published Oct 2, 2003• 142 citations
arXivHTMLPDF

Abstract

For the two-mode exciton system formed by the quasi-spin-wave collective excitation of many Lambda atoms fixed at the lattice sites of a crystal, we discover a dynamical symmetry depicted by the semidirect product algebra SU2( multiply sign in circle) h(2) in the large N limit with low excitations. With the help of the spectral generating algebra method, we obtain a larger class of exact zero-eigenvalue states adiabatically interpolating between the initial state of photon-type and the final state of quasi-spin-wave exciton-type. The conditions for the adiabatic passage of dark states are shown to be valid, even with the presence of the level degeneracy. These theoretical results can lead to the proposal of a new protocol for implementing quantum memory robust against quantum decoherence.

DOI
10.1103/physrevlett.91.147903

Related papers

Quasi-spin wave quantum memories with dynamic symmetry $SU(2)\bar{\otimes} h_2 $

C. P. Sun, Y. Li, X. F. Liu

For the two-mode exciton system formed by the quasi-spin wave collective excitation of many $\\Lambda$ atoms fixed in the lattice sites of a crystal, we discover a dynamic symmetry depicted by the semi-direct product algebra $SU(2)\\bar{\\otimes} h_2 $. With the help of the spectral generating algebra method, we exactly obtain the dressed spectra of the total system formed by the two mode excitons coupling to a single mode quantized electromagnetic field in the large N limit. The exactly-obtained solutions for the eigen-states include the class of dark states extrapolating from photon to one mode quasi-spin wave exciton. These theoretical results enlighten us to propose a protocol to implement the quantum memories robust for quantum decoherence.

•Oct 28, 2002•0 citations

Quantum Storage Based on Collective Excitations in Atomic Ensemble

Sun Chang-Pu

In this article we reviews a new protocol of quantum memory based on the quasi-pin wave excitation of the Λ systems fixed the sites of lattice. This protocol tries to avoid the disadvantage of the quantum memory scheme based on free atom ensemble, the quantum decoherence induced by the quantum leakage of collective state. Especially, we discover a universal dynamic symmetry hidden in various ensemble based quantum storage scheme. To understand the significance of this work exactly, we also give a brief introduction to our systematical studies on collective symmetric excitons in quantum ensemble, which is the necessary to propose the present scheme for quantum memory.

Yuanzihe wuli pinglun•Jan 1, 2004•0 citations

Dark-state polaritons for quantum memory in a five-level M -type atomic ensemble

Fuli Li, Ying Gu, Kai Wang +1 more

Dark-state polaritons in a five-level $M$-type atomic ensemble are proposed in the electromagnetically induced transparency. Under conditions of the low excitation limit and adiabatic following, the quantum field can be mapped onto the atomic polarization states, forming the shape preserving quantum states of polaritons. Two channels for robust quantum memory are provided, which enables the potential applications in quantum-information processing.

Physical Review A•Mar 28, 2006•12 citations

Transient dynamics of light propagation in EIT medium and hidden symmetry of multi-bit quantum memory

Y. Li, Xulin Liu, Che Sun

We investigate the transient phenomenon or property of the propagation of an optical probe field in a medium consisting of many $Λ$-type three-level atoms coupled to this probe field and an classical driven field. We observe a hidden symmetry and obtain an exact solution for this light propagation problem by means of the spectral generating method. This solution enlightens us to propose a practical protocol implementing the quantum memory robust for quantum decoherence in a crystal. As an transient dynamic process this solution also manifests an exotic result that a wave-packet of light will split into three packets propagating at different group velocities. It is argued that "super-luminal group velocity" and "sub-luminal group velocity" can be observed simultaneously in the same system. This interesting phenomenon is expected to be demonstrated experimentally.

arXiv:quant-ph/0306170•Jun 25, 2003•0 citations

Quantum Memory, Quantum Phase Gate and Polarization Entangled Photon Pairs in a Coherent Atomic System

Ying Gu, Fuli Li, Qihuang Gong +1 more

It is known that photons are the ideal carriers of quantum information and ensemble of atoms can be acted as the long lived storage and processing units. In the coherently prepared atomic ensemble with the light resonantly interacting with the atoms, various schemes have been proposed to implement quantum state transfer and storage, quantum phase gate, generation of entangled photons, and the long-distance quantum communication [1]. We first proposed the dark-state polaritons in a five-level M-type atomic ensemble in the electro magnetically induced transparency (EIT) [2], Under conditions of the low excitation limit and adiabatic following, the quantum field can be mapped onto the atomic polarization states, forming the shape preserving quantum states of polaritons. Two channels for robust quantum memory are provided. Then, we investigated the nonlinear optical response of a five-level tripod atomic system in the EIT, and proposed a three-qubit phase gate protocol based on the fifth-order nonlinearity [3]. The cross phase modulation among three weak fields induced by the fifth-order nonlinearity in EIT can produce the phase shift of order n, which can be used to realize the three-qubit polarization phase gate. Finally, we proposed a cavity-QED scheme that can effectively generate EPR polarization-entangled photon pairs [4], A four-level tripod atom successively couples to two high-Q optical cavities possessing polarization degeneracy, assisted by a classical π-polarized pump field. The stimulated Raman adiabatic passage process in the atom-cavity system is used to produce the polarization-entangled photon pairs. The proposal is particularly robust against atomic spontaneous decay. The above protocols should have potential applications in quantum information processing.

OSA Workshop on Entanglement and Quantum Decoherence•Jan 1, 2008•0 citations

Dynamics of collective excitation transfer in multimode quantum memories using multiple rapid adiabatic pulses

Ao-Lin Guo, Zhengliang Liu, Hao Wu +2 more

Multimode quantum memories are fundamental building blocks for quantum communication and networks, storing photonic quantum states in long-lived atomic spin excitations. However, their performance critically hinges on the efficiency of collective excitation transfer between photonic and spin states. Here, we theoretically and numerically investigate the dynamics of adiabatic pulses during this transfer process in atomic frequency comb-spin wave memories, comparing the standard Landau–Zener pulse, Roland–Cerf pulse and transitionless adiabatic control. We demonstrate highly efficient collective excitation transfer that is robust against variations in control-pulse amplitude and duration. Crucially, our protocol achieves rapid transfer — enhancing the capacity for stored modes — while preserving the coherence of superposition states. These results advance the development of high-fidelity, efficient manipulation in multimode quantum memories.

Modern Physics Letters A•Sep 26, 2025•0 citations
For the two-mode exciton system formed by the quasi-spin-wave collective excitation of many Lambda atoms fixed at the lattice sites of a crystal, we discover a dynamical symmetry depicted by the semidirect product algebra SU2( multiply sign in circle) h(2) in the large N limit with low excitations. With the help of the spectral generating algebra method, we obtain a larger class of exact zero-eigenvalue states adiabatically interpolating between the initial state of photon-type and the final state of quasi-spin-wave exciton-type. The conditions for the adiabatic passage of dark states are shown to be valid, even with the presence of the level degeneracy. These theoretical results can lead to the proposal of a new protocol for implementing quantum memory robust against quantum decoherence.
For the two-mode exciton system formed by the quasi-spin wave collective excitation of many Lambda\\LambdaLambda atoms fixed in the lattice sites of a crystal, we discover a dynamic symmetry depicted by the semi-direct product algebra $SU(2)\\bar{\\otimes} h_2 $. With the help of the spectral generating algebra method, we exactly obtain the dressed spectra of the total system formed by the two mode excitons coupling to a single mode quantized electromagnetic field in the large N limit. The exactly-obtained solutions for the eigen-states include the class of dark states extrapolating from photon to one mode quasi-spin wave exciton. These theoretical results enlighten us to propose a protocol to implement the quantum memories robust for quantum decoherence.
In this article we reviews a new protocol of quantum memory based on the quasi-pin wave excitation of the Λ systems fixed the sites of lattice. This protocol tries to avoid the disadvantage of the quantum memory scheme based on free atom ensemble, the quantum decoherence induced by the quantum leakage of collective state. Especially, we discover a universal dynamic symmetry hidden in various ensemble based quantum storage scheme. To understand the significance of this work exactly, we also give a brief introduction to our systematical studies on collective symmetric excitons in quantum ensemble, which is the necessary to propose the present scheme for quantum memory.
Dark-state polaritons in a five-level MMM-type atomic ensemble are proposed in the electromagnetically induced transparency. Under conditions of the low excitation limit and adiabatic following, the quantum field can be mapped onto the atomic polarization states, forming the shape preserving quantum states of polaritons. Two channels for robust quantum memory are provided, which enables the potential applications in quantum-information processing.
We investigate the transient phenomenon or property of the propagation of an optical probe field in a medium consisting of many ΛΛΛ-type three-level atoms coupled to this probe field and an classical driven field. We observe a hidden symmetry and obtain an exact solution for this light propagation problem by means of the spectral generating method. This solution enlightens us to propose a practical protocol implementing the quantum memory robust for quantum decoherence in a crystal. As an transient dynamic process this solution also manifests an exotic result that a wave-packet of light will split into three packets propagating at different group velocities. It is argued that "super-luminal group velocity" and "sub-luminal group velocity" can be observed simultaneously in the same system. This interesting phenomenon is expected to be demonstrated experimentally.
It is known that photons are the ideal carriers of quantum information and ensemble of atoms can be acted as the long lived storage and processing units. In the coherently prepared atomic ensemble with the light resonantly interacting with the atoms, various schemes have been proposed to implement quantum state transfer and storage, quantum phase gate, generation of entangled photons, and the long-distance quantum communication [1]. We first proposed the dark-state polaritons in a five-level M-type atomic ensemble in the electro magnetically induced transparency (EIT) [2], Under conditions of the low excitation limit and adiabatic following, the quantum field can be mapped onto the atomic polarization states, forming the shape preserving quantum states of polaritons. Two channels for robust quantum memory are provided. Then, we investigated the nonlinear optical response of a five-level tripod atomic system in the EIT, and proposed a three-qubit phase gate protocol based on the fifth-order nonlinearity [3]. The cross phase modulation among three weak fields induced by the fifth-order nonlinearity in EIT can produce the phase shift of order n, which can be used to realize the three-qubit polarization phase gate. Finally, we proposed a cavity-QED scheme that can effectively generate EPR polarization-entangled photon pairs [4], A four-level tripod atom successively couples to two high-Q optical cavities possessing polarization degeneracy, assisted by a classical π-polarized pump field. The stimulated Raman adiabatic passage process in the atom-cavity system is used to produce the polarization-entangled photon pairs. The proposal is particularly robust against atomic spontaneous decay. The above protocols should have potential applications in quantum information processing.
Multimode quantum memories are fundamental building blocks for quantum communication and networks, storing photonic quantum states in long-lived atomic spin excitations. However, their performance critically hinges on the efficiency of collective excitation transfer between photonic and spin states. Here, we theoretically and numerically investigate the dynamics of adiabatic pulses during this transfer process in atomic frequency comb-spin wave memories, comparing the standard Landau–Zener pulse, Roland–Cerf pulse and transitionless adiabatic control. We demonstrate highly efficient collective excitation transfer that is robust against variations in control-pulse amplitude and duration. Crucially, our protocol achieves rapid transfer — enhancing the capacity for stored modes — while preserving the coherence of superposition states. These results advance the development of high-fidelity, efficient manipulation in multimode quantum memories.