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

Journal of Modern Optics

Experimental realization of a quantum relay over a significant distance

I. Marcikic, Hugues de Riedmatten, Wolfgang Tittel, Daniel Collins, Hugo Zbinden, Nicolas Gisin

Published Apr 1, 2004• 3 citations
Publisher

Abstract

A quantum teleportation over long distances is reported. Alice's unknown quantum state carried by a 1300 nm photon is teleported onto Bob's 1550 nm photon. Bob is situated in another lab connected with the EPR source by 2 km of optical fibres and at a physical distance of 55 m. The Bell state measurement is performed between two photons that travelled through 2 km of optical fibres each. This is a simulation of a transmission of a quantum state over 6 km using quantum teleportation which is the principle of a quantum relay protocol. A fidelity of 77% is obtained which is higher than the fidelity obtained with the best protocol using not entangled particles.

DOI
10.1080/09500340408233617

Related papers

Long Distance Quantum Teleportation in a Quantum Relay Configuration

Hugues de Riedmatten, I. Marcikic, Wolfgang Tittel +3 more

A long distance quantum teleportation experiment with a fiber-delayed Bell state measurement (BSM) is reported. The source creating the qubits to be teleported and the source creating the necessary entangled state are connected to the beam splitter realizing the BSM by two 2 km long optical fibers. In addition, the teleported qubits are analyzed after 2.2 km of optical fiber, in another laboratory separated by 55 m. Time-bin qubits carried by photons at 1310 nm are teleported onto photons at 1550 nm. The fidelity is of 77%, above the maximal value obtainable without entanglement. This is the first realization of an elementary quantum relay over significant distances, which will allow an increase in the range of quantum communication and quantum key distribution.

arXiv:quant-ph/0309218•Physical Review Letters•Jan 29, 2004•203 citations

Quantum communications with time-bin entangled photons: long distance quantum teleportation and quantum repeaters

Nicolas Gisin, I. Marcikic, Hugues de Riedmatten +2 more

Using 2 km of standard telecom optical fibres, we teleport qubits carried by photons of 1310 nm wavelength to qubits in another lab carried by a photons of 1550 nm wavelength. The photons to be teleported and the necessary entangled photon pairs are created in two different non-linear crystals. The measured mean fidelity is of 81.2 %. We discuss how this could be used as quantum repeaters without quantum memories.

arXiv:quant-ph/0301181•Jan 31, 2003•2 citations

Quantum teleportation with independent sources over an optical fibre network

Qi-Chao Sun, Ya-Li Mao, Sijing Chen +15 more

Quantum teleportation faithfully transfers a quantum state between distant nodes in a network, enabling revolutionary information processing applications. Here we report teleporting quantum states over a 30 km optical fiber network with the input single photon state and the EPR state prepared independently. By buffering photons in 10 km coiled optical fiber, we perform Bell state measurement after entanglement distribution. With active feed-forward operation, the average quantum state fidelity and quantum process fidelity are measured to be 0.85 and 0.77, exceeding classical limits of 0.67 and 0.5, respectively. The statistical hypothesis test shows that the probability of a classical process to predict an average state fidelity no less than the one observed in our experiment is less than 2.4E-14, confirming the quantum nature of our quantum teleportation experiment. Our experiment marks a critical step towards the realization of quantum internet in the future.

arXiv:1602.07081•Feb 23, 2016•5 citations

Quantum State Transfer over 1200 km Assisted by Prior Distributed Entanglement

Bo Li, Yuan Wen Cao, Yu-Huai Li +13 more

Long-distance quantum state transfer (QST), which can be achieved with the help of quantum teleportation, is a core element of important quantum protocols. A typical situation for QST based on teleportation is one in which two remote communication partners (Alice and Bob) are far from the entanglement source (Charlie). Because of the atmospheric turbulence, it is challenging to implement the Bell-state measurement after photons propagate in atmospheric channels. In previous long-distance free-space experiments, Alice and Charlie always perform local Bell-state measurement before the entanglement distribution process is completed. Here, by developing a highly stable interferometer to project the photon into a hybrid path-polarization dimension and utilizing the satellite-borne entangled photon source, we demonstrate proof-of-principle QST at the distance of over 1200 km assisted by prior quantum entanglement shared between two distant ground stations with the satellite Micius. The average fidelity of transferred six distinct quantum states is 0.82±0.01, exceeding the classical limit of 2/3 on a single copy of a qubit.

Physical Review Letters•Apr 26, 2022•42 citations

Teleportation as a measure of entanglement for an arbitrary state of two qubits

J. Grondalski, Daniel F. V. James

Summary form only given. Characterizing the entanglement of a general bipartite quantum system is a difficult problem. Most measures involve difficult extremizations and their physical motivation is not always clear. In this paper we propose an experimental measure of entanglement based on a modified version of the familiar teleportation protocol of Bennett et al. (1993). Briefly, teleportation traditionally involves two parties, Alice and Bob. Initially, Alice has a qubit in an unknown quantum state which she would like to communicate to Bob and Bob has two qubits in an entangled Einstein-Podolsky-Rosen (EPR) pair. To accomplish this transfer, Bob shares one qubit of his EPR pair with Alice. She then performs a joint measurement or Bell measurement on her two qubits and relays this information back to Bob over a classical channel. Bob then uses the outcome of Alice's Bell measurement to transform his qubit, with a local unitary transformation, into the original quantum state, always with a fidelity of one.

Quantum Electronics and Laser Science Conference•Jun 25, 2003•0 citations

Long-distance quantum teleportation assisted with free-space entanglement distribution

Ji-Gang Ren, Yang Bin, Zhenhuan Yi +4 more

Faithful long-distance quantum teleportation necessitates prior entanglement distribution between two communicated locations. The particle carrying on the unknown quantum information is then combined with one particle of the entangled states for Bell-state measurements, which leads to a transfer of the original quantum information onto the other particle of the entangled states. However in most of the implemented teleportation experiments nowadays, the Bell-state measurements are performed even before successful distribution of entanglement. This leads to an instant collapse of the quantum state for the transmitted particle, which is actually a single-particle transmission thereafter. Thus the true distance for quantum teleportation is, in fact, only in a level of meters. In the present experiment we design a novel scheme which has overcome this limit by utilizing fiber as quantum memory. A complete quantum teleportation is achieved upon successful entanglement distribution over 967 meters in public free space. Active feed-forward control techniques are developed for real-time transfer of quantum information. The overall experimental fidelities for teleported states are better than 89.6%, which signify high-quality teleportation.

Chinese Physics B•Jul 31, 2009•7 citations
A quantum teleportation over long distances is reported. Alice's unknown quantum state carried by a 1300 nm photon is teleported onto Bob's 1550 nm photon. Bob is situated in another lab connected with the EPR source by 2 km of optical fibres and at a physical distance of 55 m. The Bell state measurement is performed between two photons that travelled through 2 km of optical fibres each. This is a simulation of a transmission of a quantum state over 6 km using quantum teleportation which is the principle of a quantum relay protocol. A fidelity of 77% is obtained which is higher than the fidelity obtained with the best protocol using not entangled particles.
A long distance quantum teleportation experiment with a fiber-delayed Bell state measurement (BSM) is reported. The source creating the qubits to be teleported and the source creating the necessary entangled state are connected to the beam splitter realizing the BSM by two 2 km long optical fibers. In addition, the teleported qubits are analyzed after 2.2 km of optical fiber, in another laboratory separated by 55 m. Time-bin qubits carried by photons at 1310 nm are teleported onto photons at 1550 nm. The fidelity is of 77%, above the maximal value obtainable without entanglement. This is the first realization of an elementary quantum relay over significant distances, which will allow an increase in the range of quantum communication and quantum key distribution.
Quantum teleportation faithfully transfers a quantum state between distant nodes in a network, enabling revolutionary information processing applications. Here we report teleporting quantum states over a 30 km optical fiber network with the input single photon state and the EPR state prepared independently. By buffering photons in 10 km coiled optical fiber, we perform Bell state measurement after entanglement distribution. With active feed-forward operation, the average quantum state fidelity and quantum process fidelity are measured to be 0.85 and 0.77, exceeding classical limits of 0.67 and 0.5, respectively. The statistical hypothesis test shows that the probability of a classical process to predict an average state fidelity no less than the one observed in our experiment is less than 2.4E-14, confirming the quantum nature of our quantum teleportation experiment. Our experiment marks a critical step towards the realization of quantum internet in the future.
Long-distance quantum state transfer (QST), which can be achieved with the help of quantum teleportation, is a core element of important quantum protocols. A typical situation for QST based on teleportation is one in which two remote communication partners (Alice and Bob) are far from the entanglement source (Charlie). Because of the atmospheric turbulence, it is challenging to implement the Bell-state measurement after photons propagate in atmospheric channels. In previous long-distance free-space experiments, Alice and Charlie always perform local Bell-state measurement before the entanglement distribution process is completed. Here, by developing a highly stable interferometer to project the photon into a hybrid path-polarization dimension and utilizing the satellite-borne entangled photon source, we demonstrate proof-of-principle QST at the distance of over 1200 km assisted by prior quantum entanglement shared between two distant ground stations with the satellite Micius. The average fidelity of transferred six distinct quantum states is 0.82±0.01, exceeding the classical limit of 2/3 on a single copy of a qubit.
Summary form only given. Characterizing the entanglement of a general bipartite quantum system is a difficult problem. Most measures involve difficult extremizations and their physical motivation is not always clear. In this paper we propose an experimental measure of entanglement based on a modified version of the familiar teleportation protocol of Bennett et al. (1993). Briefly, teleportation traditionally involves two parties, Alice and Bob. Initially, Alice has a qubit in an unknown quantum state which she would like to communicate to Bob and Bob has two qubits in an entangled Einstein-Podolsky-Rosen (EPR) pair. To accomplish this transfer, Bob shares one qubit of his EPR pair with Alice. She then performs a joint measurement or Bell measurement on her two qubits and relays this information back to Bob over a classical channel. Bob then uses the outcome of Alice's Bell measurement to transform his qubit, with a local unitary transformation, into the original quantum state, always with a fidelity of one.
Faithful long-distance quantum teleportation necessitates prior entanglement distribution between two communicated locations. The particle carrying on the unknown quantum information is then combined with one particle of the entangled states for Bell-state measurements, which leads to a transfer of the original quantum information onto the other particle of the entangled states. However in most of the implemented teleportation experiments nowadays, the Bell-state measurements are performed even before successful distribution of entanglement. This leads to an instant collapse of the quantum state for the transmitted particle, which is actually a single-particle transmission thereafter. Thus the true distance for quantum teleportation is, in fact, only in a level of meters. In the present experiment we design a novel scheme which has overcome this limit by utilizing fiber as quantum memory. A complete quantum teleportation is achieved upon successful entanglement distribution over 967 meters in public free space. Active feed-forward control techniques are developed for real-time transfer of quantum information. The overall experimental fidelities for teleported states are better than 89.6%, which signify high-quality teleportation.