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:0811.2270 · Physical Review A

Robust quantum repeater with atomic ensembles and single-photon sources

Fang-Yu Hong, Shi‐Jie Xiong

Published May 28, 2009• 6 citations
arXivHTMLPDF

Abstract

We present an efficient scheme for generating high-fidelity entanglement locally which is essential for quantum repeater protocols. Two local ``polarization'' entangled states of atomic ensembles $u$ and $d$ are generated by absorbing a single photon emitted by on-demand single-photon sources, based on which high-fidelity local entanglement between four ensembles can be established efficiently through Bell-state measurement. Entanglement in basic links and entanglement connection between links are carried out by the use of two-photon interference. In addition to being robust against phase fluctuations in the quantum channels, this scheme may speed up quantum communication with higher fidelity compared with the partial read protocol [Sangouard et al., Phys. Rev. A 77, 062301 (2008)] which may generate entanglement most quickly among the previous schemes with the same ingredients.

DOI
10.1103/physreva.79.052341

Related papers

Robust and efficient quantum repeaters with atomic ensembles and linear optics

Nicolas Sangouard, Christoph Simon, Bo Zhao +4 more

In the last few years there has been a lot of interest in quantum repeater protocols using only atomic ensembles and linear optics. Here we show that the local generation of high-fidelity entangled pairs of atomic excitations, in combination with the use of two-photon detections for long-distance entanglement generation, permits the implementation of a very attractive quantum repeater protocol. Such a repeater is robust with respect to phase fluctuations in the transmission channels, and at the same time achieves higher entanglement generation rates than other protocols using the same ingredients. We propose an efficient method of generating high-fidelity entangled pairs locally, based on the partial readout of the ensemble-based memories. We also discuss the experimental implementation of the proposed protocol.

arXiv:0802.1475•Physical Review A•Jun 2, 2008•163 citations

Robust long-distance quantum communication with atomic ensembles and linear optics

Bo Zhao, Zeng‐Bing Chen, Yu-Ao Chen +2 more

Quantum communication deals with absolutely secure transfer of classical messages by means of quantum cryptography or faithful transfer of unknown quantum states by means of quantum teleportation between distant sites. The essential element for quantum communication is to create remote entangled pairs of high fidelity. The main difficulty to create such a distant entangled pair is that both photon loss and decoherence grow exponentially with distance. However, with the help of quantum repeater, it is demonstrated that both the entanglement sources and the time needed to create a single distant entangled pair of high fidelity could scale polynomially with the communication length. Here we propose a robust quantum repeater by extending the original Duan-Lukin-Cirac-Zoller (DLCZ) scheme based on atomic ensembles and linear optics. Our protocol entails the advantage of two photon interference, which is more robust than single photon interference used in the DLCZ scheme. In comparison with our previous proposal, the entangled memory qubits are manipulated across long distance, and local entanglement pairs are avoided. Our proposal provides an exciting possibility for realistic long distance quantum communication.

•Sep 20, 2006•6 citations

Quantum repeaters based on heralded qubit amplifiers

Jiří Minář, Hugues de Riedmatten, Nicolas Sangouard

We present a quantum repeater scheme based on the recently proposed qubit amplifier [N. Gisin, S. Pironio, and N. Sangouard, Phys. Rev. Lett. 105, 070501 (2010)]. It relies on an on-demand entangled-photon-pair source which uses on-demand single-photon sources, linear optical elements, and atomic ensembles. Interestingly, the imperfections affecting the states created from this source, caused, for example, by detectors with nonunit efficiencies, are systematically purified from an entanglement swapping operation based on a two-photon detection. This allows the distribution of entanglement over very long distances with a high fidelity, that is, without vacuum components and multiphoton errors. Therefore, the resulting quantum repeater architecture does not necessitate final postselections and thus achieves high entanglement distribution rates. This also provides unique opportunities for device-independent quantum key distribution over long distances with linear optics and atomic ensembles.

arXiv:1111.5185•Physical Review A•Mar 13, 2012•35 citations

Quantum repeaters based on deterministic storage of a single photon in distant atomic ensembles

Davit Aghamalyan, Yu. P. Malakyan

Quantum repeaters hold the promise to prevent the photon losses in communication channels. Most recently, the serious efforts have been applied to achieve scalable distribution of entanglement over long distances. However, the probabilistic nature of entanglement generation and realistic quantum memory storage times make the implementation of quantum repeaters an outstanding experimental challenge. We propose a quantum repeater protocol based on the deterministic storage of a single photon in atomic ensembles confined in distant high-finesse cavities and show that this system is capable of distributing the entanglement over long distances with a much higher rate as compared to previous protocols, thereby alleviating the limitations on the quantum memory lifetime by several orders of magnitude. Our scheme is robust with respect to phase fluctuations in the quantum channel, while the fidelity imperfection is fixed and negligibly small at each step of entanglement swapping.

arXiv:1110.2553•Physical Review A•Oct 4, 2011•9 citations

Robust quantum repeater with atomic ensembles against phase and polarization instability

Ming Gao, Lin-Mei Liang, Cheng-Zu Li +1 more

We propose an alternative scheme for quantum repeater without phase stabilization and polarization calibration of photons transmitted over long-distance channel. We introduce time-bin photonic states and use a two-photon interference configuration to robustly generate entanglement between distant atomic-ensemble-based memory qubits. Our scheme can be performed with current experimental setups through making some simple adjustments.

arXiv:0903.1977•Physical Review A•Apr 1, 2009•12 citations

Heralded high-efficiency quantum repeater with atomic ensembles assisted by faithful single-photon transmission

Tao Li, Fu‐Guo Deng

Quantum repeater is one of the important building blocks for long distance quantum communication network. The previous quantum repeaters based on atomic ensembles and linear optical elements can only be performed with a maximal success probability of 1/2 during the entanglement creation and entanglement swapping procedures. Meanwhile, the polarization noise during the entanglement distribution process is harmful to the entangled channel created. Here we introduce a general interface between a polarized photon and an atomic ensemble trapped in a single-sided optical cavity, and with which we propose a high-efficiency quantum repeater protocol in which the robust entanglement distribution is accomplished by the stable spatial-temporal entanglement and it can in principle create the deterministic entanglement between neighboring atomic ensembles in a heralded way as a result of cavity quantum electrodynamics. Meanwhile, the simplified parity-check gate makes the entanglement swapping be completed with unity efficiency, other than 1/2 with linear optics. We detail the performance of our protocol with current experimental parameters and show its robustness to the imperfections, i.e., detuning and coupling variation, involved in the reflection process. These good features make it a useful building block in long distance quantum communication.

arXiv:1511.00095•Scientific Reports•Oct 27, 2015•29 citations
We present an efficient scheme for generating high-fidelity entanglement locally which is essential for quantum repeater protocols. Two local ``polarization'' entangled states of atomic ensembles uuu and ddd are generated by absorbing a single photon emitted by on-demand single-photon sources, based on which high-fidelity local entanglement between four ensembles can be established efficiently through Bell-state measurement. Entanglement in basic links and entanglement connection between links are carried out by the use of two-photon interference. In addition to being robust against phase fluctuations in the quantum channels, this scheme may speed up quantum communication with higher fidelity compared with the partial read protocol [Sangouard et al., Phys. Rev. A 77, 062301 (2008)] which may generate entanglement most quickly among the previous schemes with the same ingredients.
In the last few years there has been a lot of interest in quantum repeater protocols using only atomic ensembles and linear optics. Here we show that the local generation of high-fidelity entangled pairs of atomic excitations, in combination with the use of two-photon detections for long-distance entanglement generation, permits the implementation of a very attractive quantum repeater protocol. Such a repeater is robust with respect to phase fluctuations in the transmission channels, and at the same time achieves higher entanglement generation rates than other protocols using the same ingredients. We propose an efficient method of generating high-fidelity entangled pairs locally, based on the partial readout of the ensemble-based memories. We also discuss the experimental implementation of the proposed protocol.
Quantum communication deals with absolutely secure transfer of classical messages by means of quantum cryptography or faithful transfer of unknown quantum states by means of quantum teleportation between distant sites. The essential element for quantum communication is to create remote entangled pairs of high fidelity. The main difficulty to create such a distant entangled pair is that both photon loss and decoherence grow exponentially with distance. However, with the help of quantum repeater, it is demonstrated that both the entanglement sources and the time needed to create a single distant entangled pair of high fidelity could scale polynomially with the communication length. Here we propose a robust quantum repeater by extending the original Duan-Lukin-Cirac-Zoller (DLCZ) scheme based on atomic ensembles and linear optics. Our protocol entails the advantage of two photon interference, which is more robust than single photon interference used in the DLCZ scheme. In comparison with our previous proposal, the entangled memory qubits are manipulated across long distance, and local entanglement pairs are avoided. Our proposal provides an exciting possibility for realistic long distance quantum communication.
We present a quantum repeater scheme based on the recently proposed qubit amplifier [N. Gisin, S. Pironio, and N. Sangouard, Phys. Rev. Lett. 105, 070501 (2010)]. It relies on an on-demand entangled-photon-pair source which uses on-demand single-photon sources, linear optical elements, and atomic ensembles. Interestingly, the imperfections affecting the states created from this source, caused, for example, by detectors with nonunit efficiencies, are systematically purified from an entanglement swapping operation based on a two-photon detection. This allows the distribution of entanglement over very long distances with a high fidelity, that is, without vacuum components and multiphoton errors. Therefore, the resulting quantum repeater architecture does not necessitate final postselections and thus achieves high entanglement distribution rates. This also provides unique opportunities for device-independent quantum key distribution over long distances with linear optics and atomic ensembles.
Quantum repeaters hold the promise to prevent the photon losses in communication channels. Most recently, the serious efforts have been applied to achieve scalable distribution of entanglement over long distances. However, the probabilistic nature of entanglement generation and realistic quantum memory storage times make the implementation of quantum repeaters an outstanding experimental challenge. We propose a quantum repeater protocol based on the deterministic storage of a single photon in atomic ensembles confined in distant high-finesse cavities and show that this system is capable of distributing the entanglement over long distances with a much higher rate as compared to previous protocols, thereby alleviating the limitations on the quantum memory lifetime by several orders of magnitude. Our scheme is robust with respect to phase fluctuations in the quantum channel, while the fidelity imperfection is fixed and negligibly small at each step of entanglement swapping.
Quantum repeater is one of the important building blocks for long distance quantum communication network. The previous quantum repeaters based on atomic ensembles and linear optical elements can only be performed with a maximal success probability of 1/2 during the entanglement creation and entanglement swapping procedures. Meanwhile, the polarization noise during the entanglement distribution process is harmful to the entangled channel created. Here we introduce a general interface between a polarized photon and an atomic ensemble trapped in a single-sided optical cavity, and with which we propose a high-efficiency quantum repeater protocol in which the robust entanglement distribution is accomplished by the stable spatial-temporal entanglement and it can in principle create the deterministic entanglement between neighboring atomic ensembles in a heralded way as a result of cavity quantum electrodynamics. Meanwhile, the simplified parity-check gate makes the entanglement swapping be completed with unity efficiency, other than 1/2 with linear optics. We detail the performance of our protocol with current experimental parameters and show its robustness to the imperfections, i.e., detuning and coupling variation, involved in the reflection process. These good features make it a useful building block in long distance quantum communication.