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

European Quantum Electronics Conference (EQEC)

Quantum memory for light

Brian Julsgaard, Jacob Friis Sherson, Eugene Simon Polzik, J. Fiurdek, J. Ignacio Cirac

Published Jan 18, 2006• 0 citations
Publisher

Abstract

The work reports on the experiments performed implementing quantum memory for light utilizing an atomic spin polarized gas of caesium atoms. The fidelity of the mapping up to 70%, significantly higher than the benchmark classical memory fidelity has been demonstrated. Future plans for extending the memory performance towards other quantum states of light and the memory readout protocols is described in the paper.

DOI
10.1109/eqec.2005.1567462

Related papers

A single-atom quantum memory

Eden V. Figueroa, Holger Specht, Christian Nölleke +4 more

We show the implementation of the most fundamental quantum memory by mapping arbitrary polarization states of light into and out of a single atom trapped inside an optical cavity. The memory performance is analyzed through full quantum process tomography. The average fidelity is measured to be 93% and low decoherence rates result in storage times exceeding 180µs.

International Conference on Quantum Information•Jan 1, 2011•9 citations

Entanglement and quantum memory with atomic ensembles

Eugene Simon Polzik, Brian Julsgaard, Jens Lykke Sørensen +1 more

Summary form only given. A new approach to the problem of the quantum interface between light and atoms has been recently developed. The method utilizes free space dispersive interaction between pulses of light and spin polarized atomic ensembles. Entanglement between the polarization state of light and the collective spin state of atoms is established by measurement, more precisely by detection of light in a certain polarization basis. In the first demonstration of this approach we have generated a long-lived entangled state of two separate macroscopic atomic samples by a polarization measurement on light transmitted through the samples. We then have shown that this approach also works for mapping of a quantum state of light onto long-lived atomic spin state paving the road towards realization of the quantum memory for light. Recently we have also extended the free space light-atoms interface beyond the continuous variables in the proposal, where a coherent superposition "cat" state of an atomic ensemble is generated by a measurement sequence. Progress with other communication protocols such as atomic state teleportation and multiparty networks will be presented.

European Quantum Electronics Conference (EQEC)•Jan 1, 2003•0 citations

Single-cell atomic quantum memory for light

Tomáš Opatrný

Recent experiments demonstrating atomic quantum memory for light [B. Julsgaard et al., Nature 432, 482 (2004)] involve two macroscopic samples of atoms, each with opposite spin polarization. It is shown here that a single atomic cell is enough for the memory function if the atoms are optically pumped with suitable linearly polarized light, and quadratic Zeeman shift and/or ac Stark shift are used to manipulate rotations of the quadratures. This should enhance the performance of our quantum memory devices since less resources are needed and losses of light in crossing different media boundaries are avoided.

arXiv:quant-ph/0509094•Physical Review A•Oct 11, 2006•5 citations

Highly-efficient quantum memory for polarization qubits in a spatially-multiplexed cold atomic ensemble

Pierre Vernaz-Gris, Kun Huang, Mingtao Cao +2 more

Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.

arXiv:1707.09372•Nature Communications•Jan 19, 2018•181 citations

Room-Temperature Single-photon level Memory for Polarization States

Connor Kupchak, Thomas Mittiga, Bertus Jordaan +3 more

An optical quantum memory is a stationary device that is capable of storing and recreating photonic qubits with a higher fidelity than any classical device. Thus far, these two requirements have been fulfilled for polarization qubits in systems based on cold atoms and cryogenically cooled crystals. Here, we report a room-temperature memory capable of storing arbitrary polarization qubits with a signal-to-background ratio higher than 1 and an average fidelity surpassing the classical benchmark for weak laser pulses containing 1.6 photons on average, without taking into account non-unitary operation. Our results demonstrate that a common vapor cell can reach the low background noise levels necessary for polarization qubit storage using single-photon level light, and propels atomic-vapor systems towards a level of functionality akin to other quantum information processing architectures.

Scientific Reports•Jan 7, 2015•35 citations

Atomic spins as a storage medium for quantum fluctuations of light

Brian Julsgaard, C. Schori, Jens Lykke Sørensen +1 more

We review recent results showing the possibility to use off-resonant light/matter interaction for the purpose of quantum memory. A quantum state of atomic spins can be read out by light in a process which is a quantum analogue of the classical Faraday effect. Conversely, the dynamic Stark effect opens up the opportunity for recording the polarization state of light onto the atomic spin memory. We demonstrate that a sample of cesium atoms under appropriate conditions has the sensitivity to record properties of just a few photons, thus being a feasible candidate for quantum memory for light.

Quantum Information and Computation•Oct 1, 2003•8 citations
The work reports on the experiments performed implementing quantum memory for light utilizing an atomic spin polarized gas of caesium atoms. The fidelity of the mapping up to 70%, significantly higher than the benchmark classical memory fidelity has been demonstrated. Future plans for extending the memory performance towards other quantum states of light and the memory readout protocols is described in the paper.
Summary form only given. A new approach to the problem of the quantum interface between light and atoms has been recently developed. The method utilizes free space dispersive interaction between pulses of light and spin polarized atomic ensembles. Entanglement between the polarization state of light and the collective spin state of atoms is established by measurement, more precisely by detection of light in a certain polarization basis. In the first demonstration of this approach we have generated a long-lived entangled state of two separate macroscopic atomic samples by a polarization measurement on light transmitted through the samples. We then have shown that this approach also works for mapping of a quantum state of light onto long-lived atomic spin state paving the road towards realization of the quantum memory for light. Recently we have also extended the free space light-atoms interface beyond the continuous variables in the proposal, where a coherent superposition "cat" state of an atomic ensemble is generated by a measurement sequence. Progress with other communication protocols such as atomic state teleportation and multiparty networks will be presented.
Recent experiments demonstrating atomic quantum memory for light [B. Julsgaard et al., Nature 432, 482 (2004)] involve two macroscopic samples of atoms, each with opposite spin polarization. It is shown here that a single atomic cell is enough for the memory function if the atoms are optically pumped with suitable linearly polarized light, and quadratic Zeeman shift and/or ac Stark shift are used to manipulate rotations of the quadratures. This should enhance the performance of our quantum memory devices since less resources are needed and losses of light in crossing different media boundaries are avoided.
Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.
An optical quantum memory is a stationary device that is capable of storing and recreating photonic qubits with a higher fidelity than any classical device. Thus far, these two requirements have been fulfilled for polarization qubits in systems based on cold atoms and cryogenically cooled crystals. Here, we report a room-temperature memory capable of storing arbitrary polarization qubits with a signal-to-background ratio higher than 1 and an average fidelity surpassing the classical benchmark for weak laser pulses containing 1.6 photons on average, without taking into account non-unitary operation. Our results demonstrate that a common vapor cell can reach the low background noise levels necessary for polarization qubit storage using single-photon level light, and propels atomic-vapor systems towards a level of functionality akin to other quantum information processing architectures.
We review recent results showing the possibility to use off-resonant light/matter interaction for the purpose of quantum memory. A quantum state of atomic spins can be read out by light in a process which is a quantum analogue of the classical Faraday effect. Conversely, the dynamic Stark effect opens up the opportunity for recording the polarization state of light onto the atomic spin memory. We demonstrate that a sample of cesium atoms under appropriate conditions has the sensitivity to record properties of just a few photons, thus being a feasible candidate for quantum memory for light.