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

IEEE Vehicular Technology Conference

Efficient Entanglement Distillation of Solid Qubits Using Non-Reciprocal Microresonators

Wei‐Chao Gao, Chuan Xi Wang

Published Jun 1, 2017• 0 citations
Publisher

Abstract

Recently, long distance of quantum communication relies on efficient quantum repeaters, and the distribution of maximal entanglement is a key technique for it. Especially, the distribution of entanglement with high-fidelity relies on the entanglement purification and concentration. Here we present a system to realize the entanglement purification for λ-type three-level entangled quantum dots by using the whispering-gallery-mode microcavity. Also we design a parity check gate on solid qubits that allows the quantum nondemolition measurement on the remote qubits. Moreover, one can distill a high-fidelity entangled solid state ensemble from a mixed-entangled state ensemble nonlocally.

DOI
10.1109/vtcspring.2017.8108693

Related papers

Imperfect-interaction-free entanglement purification on stationary systems for solid quantum repeaters

Guan-Yu Wang, Qing Ai, Fu‐Guo Deng +1 more

Solid quantum repeater is a core part in a large-scale quantum network. Entanglement purification, the key technique in a quantum repeater, is used to distill high-quality nonlocal entanglement from an ensemble in a mixed entangled state and to depress the vicious influence on quantum information carriers caused by noise. Here, we present an imperfect-interaction-free entanglement purification on nonlocal electron spins in quantum dots for solid quantum repeaters, using faithful parity check on electron spins. The faithful parity check can make correct judgement on the parity mode without destructing the nonlocal solid entanglement even with the imperfect interaction between a QD embedded inside a microcavity and a circularly polarized photon in the nearly realistic condition. Therefore, the imperfect-interaction-free entanglement purification can prevent the maximally entangled states from being changed into partially entangled ones and guarantee the fidelity of the nonlocal mixed state to a desired one after purification. As this scheme is feasible in the nearly realistic condition with imperfect interaction, the requirements for experimental implementation will be relaxed. These distinctive features make this imperfect-interaction-free entanglement purification have more practical applications in solid quantum repeaters for a large-scale quantum network.

Optics Express•Jun 2, 2020•10 citations

Efficient hyperentanglement purification using a Λ system coupled with a whispering-gallery-mode microresonator

Dezhi Chen, Chang Shi, Tie-Jun Wang

Entanglement purification is of great importance in long-distance quantum communications and distributed quantum computations. Here we present an efficient scheme for the hyperentanglement purification (HP) of a two-photon system by using a high-dimensional logical gate device which is composed of atoms and a quantized whispering-gallery-mode microresonator. In the present scheme, one can complete the HP and entanglement storage in one step without resorting to additional qubits. Compared with the conventional HP schemes in which the two-qubit two-dimensional parity-checking measurements are used to correct the bit-flip errors, our scheme, which explored the high-dimensional controlled-flip operation, shows a wide distillation range with a higher fidelity. The remaining resources of the failed HP processing can be used to purify the other pair hyperentangled photons. Therefore, the efficiency of our scheme is higher than the previous schemes. The implementation of our HP is assisted by nitrogen-vacancy centers in optical microresonators, which could be achieved with current techniques.

Journal of the Optical Society of America B•Jan 30, 2018•1 citation

Atomic entanglement purification and concentration using coherent state input-output process in low-Q cavity QED regime

Cong Cao, Chuan Xi Wang, Lingyan He +1 more

We investigate an atomic entanglement purification protocol based on the coherent state input-output process by working in low-Q cavity in the atom-cavity intermediate coupling region. The information of entangled states are encoded in three-level configured single atoms confined in separated one-side optical micro-cavities. Using the coherent state input-output process, we design a two-qubit parity check module (PCM), which allows the quantum nondemolition measurement for the atomic qubits, and show its use for remote parities to distill a high-fidelity atomic entangled ensemble from an initial mixed state ensemble nonlocally. The proposed scheme can further be used for unknown atomic states entanglement concentration. Also by exploiting the PCM, we describe a modified scheme for atomic entanglement concentration by introducing ancillary single atoms. As the coherent state input-output process is robust and scalable in realistic applications, and the detection in the PCM is based on the intensity of outgoing coherent state, the present protocols may be widely used in large-scaled and solid-based quantum repeater and quantum information processing.

Optics Express•Feb 11, 2013•81 citations

Long-Distance Entanglement Purification for Quantum Communication

Xiao‐Min Hu, Cen-Xiao Huang, Yu‐Bo Sheng +8 more

High-quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in tabletop. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled state. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gates, the total purification efficiency can be estimated as 6.6×10^{3} times than the experiment using two pairs of entangled states with spontaneous parametric down-conversion sources. Our results offer the potential to be implemented as part of a full quantum repeater and large-scale quantum network.

arXiv:2101.07441•Physical Review Letters•Jan 8, 2021•279 citations

High-efficient entanglement distillation from photon loss and decoherence

Tie-Jun Wang, Chuan Xi Wang

We illustrate an entanglement distillation protocol (EDP) for a mixed photon-ensemble which composed of four kinds of entangled states and vacuum states. Exploiting the linear optics and local entanglement resource (four-qubit entangled GHZ state), we design the nondemolition parity-checking and qubit amplifying (PCQA) setup for photonic polarization degree of freedom which are the key device of our scheme. With the PCQA setup, a high-fidelity entangled photon-pair system can be achieved against the transmission losses and the decoherence in noisy channels. And in the available purification range for our EDP, the fidelity of this ensemble can be improved to the maximal value through iterated operations. Compared to the conventional entanglement purification schemes, our scheme largely reduces the initialization requirement of the distilled mixed quantum system, and overcomes the difficulties posed by inherent channel losses during photon transmission. All these advantages make this scheme more useful in the practical applications of long-distance quantum communication.

Optics Express•Nov 24, 2015•18 citations

High-fidelity entanglement purification using chains of atoms and optical cavities

Denis Gonţa, Peter van Loock

In our previous paper [D. Gon\ifmmode \mbox{\c{t}}\else \c{t}\fi{}a and P. van Loock, Phys. Rev. A 84, 042303 (2011)], we proposed an efficient scheme to purify dynamically a bipartite entangled state using short chains of atoms coupled to high-finesse optical cavities. In contrast to conventional entanglement purification protocols, we avoid controlled-not gates and thus reduce complicated pulse sequences and superfluous qubit operations. In this paper, we significantly improve the output fidelity of remotely entangled atoms by introducing one additional entanglement protocol in each of the repeater nodes and by optimizing the laser beams required to control the entire scheme. Our improved distillation scheme yields an almost-unit output fidelity that, together with the entanglement distribution and swapping, opens an attractive route towards an efficient and experimentally feasible quantum repeater for long-distance quantum communication.

arXiv:1207.6008•Physical Review A•Nov 9, 2012•25 citations
Recently, long distance of quantum communication relies on efficient quantum repeaters, and the distribution of maximal entanglement is a key technique for it. Especially, the distribution of entanglement with high-fidelity relies on the entanglement purification and concentration. Here we present a system to realize the entanglement purification for λ-type three-level entangled quantum dots by using the whispering-gallery-mode microcavity. Also we design a parity check gate on solid qubits that allows the quantum nondemolition measurement on the remote qubits. Moreover, one can distill a high-fidelity entangled solid state ensemble from a mixed-entangled state ensemble nonlocally.
Solid quantum repeater is a core part in a large-scale quantum network. Entanglement purification, the key technique in a quantum repeater, is used to distill high-quality nonlocal entanglement from an ensemble in a mixed entangled state and to depress the vicious influence on quantum information carriers caused by noise. Here, we present an imperfect-interaction-free entanglement purification on nonlocal electron spins in quantum dots for solid quantum repeaters, using faithful parity check on electron spins. The faithful parity check can make correct judgement on the parity mode without destructing the nonlocal solid entanglement even with the imperfect interaction between a QD embedded inside a microcavity and a circularly polarized photon in the nearly realistic condition. Therefore, the imperfect-interaction-free entanglement purification can prevent the maximally entangled states from being changed into partially entangled ones and guarantee the fidelity of the nonlocal mixed state to a desired one after purification. As this scheme is feasible in the nearly realistic condition with imperfect interaction, the requirements for experimental implementation will be relaxed. These distinctive features make this imperfect-interaction-free entanglement purification have more practical applications in solid quantum repeaters for a large-scale quantum network.
Entanglement purification is of great importance in long-distance quantum communications and distributed quantum computations. Here we present an efficient scheme for the hyperentanglement purification (HP) of a two-photon system by using a high-dimensional logical gate device which is composed of atoms and a quantized whispering-gallery-mode microresonator. In the present scheme, one can complete the HP and entanglement storage in one step without resorting to additional qubits. Compared with the conventional HP schemes in which the two-qubit two-dimensional parity-checking measurements are used to correct the bit-flip errors, our scheme, which explored the high-dimensional controlled-flip operation, shows a wide distillation range with a higher fidelity. The remaining resources of the failed HP processing can be used to purify the other pair hyperentangled photons. Therefore, the efficiency of our scheme is higher than the previous schemes. The implementation of our HP is assisted by nitrogen-vacancy centers in optical microresonators, which could be achieved with current techniques.
We investigate an atomic entanglement purification protocol based on the coherent state input-output process by working in low-Q cavity in the atom-cavity intermediate coupling region. The information of entangled states are encoded in three-level configured single atoms confined in separated one-side optical micro-cavities. Using the coherent state input-output process, we design a two-qubit parity check module (PCM), which allows the quantum nondemolition measurement for the atomic qubits, and show its use for remote parities to distill a high-fidelity atomic entangled ensemble from an initial mixed state ensemble nonlocally. The proposed scheme can further be used for unknown atomic states entanglement concentration. Also by exploiting the PCM, we describe a modified scheme for atomic entanglement concentration by introducing ancillary single atoms. As the coherent state input-output process is robust and scalable in realistic applications, and the detection in the PCM is based on the intensity of outgoing coherent state, the present protocols may be widely used in large-scaled and solid-based quantum repeater and quantum information processing.
High-quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in tabletop. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled state. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gates, the total purification efficiency can be estimated as 6.6×10^{3} times than the experiment using two pairs of entangled states with spontaneous parametric down-conversion sources. Our results offer the potential to be implemented as part of a full quantum repeater and large-scale quantum network.
We illustrate an entanglement distillation protocol (EDP) for a mixed photon-ensemble which composed of four kinds of entangled states and vacuum states. Exploiting the linear optics and local entanglement resource (four-qubit entangled GHZ state), we design the nondemolition parity-checking and qubit amplifying (PCQA) setup for photonic polarization degree of freedom which are the key device of our scheme. With the PCQA setup, a high-fidelity entangled photon-pair system can be achieved against the transmission losses and the decoherence in noisy channels. And in the available purification range for our EDP, the fidelity of this ensemble can be improved to the maximal value through iterated operations. Compared to the conventional entanglement purification schemes, our scheme largely reduces the initialization requirement of the distilled mixed quantum system, and overcomes the difficulties posed by inherent channel losses during photon transmission. All these advantages make this scheme more useful in the practical applications of long-distance quantum communication.
In our previous paper [D. Gon\ifmmode \mbox{\c{t}}\else \c{t}\fi{}a and P. van Loock, Phys. Rev. A 84, 042303 (2011)], we proposed an efficient scheme to purify dynamically a bipartite entangled state using short chains of atoms coupled to high-finesse optical cavities. In contrast to conventional entanglement purification protocols, we avoid controlled-not gates and thus reduce complicated pulse sequences and superfluous qubit operations. In this paper, we significantly improve the output fidelity of remotely entangled atoms by introducing one additional entanglement protocol in each of the repeater nodes and by optimizing the laser beams required to control the entire scheme. Our improved distillation scheme yields an almost-unit output fidelity that, together with the entanglement distribution and swapping, opens an attractive route towards an efficient and experimentally feasible quantum repeater for long-distance quantum communication.