# Long-Distance Free-Space Distribution of Quantum Entanglement

@article{Aspelmeyer2003LongDistanceFD, title={Long-Distance Free-Space Distribution of Quantum Entanglement}, author={Markus Aspelmeyer and Hannes R. B{\"o}hm and Tsewang Gyatso and Thomas Jennewein and Rainer Kaltenbaek and Michael Lindenthal and Gabriel Molina-Terriza and Andreas Poppe and Kevin J. Resch and Michael Taraba and Rupert Ursin and Philip Walther and Anton Zeilinger}, journal={Science}, year={2003}, volume={301}, pages={621 - 623} }

We demonstrate the distribution of quantum entanglement via optical free-space links to independent receivers separated by 600 m, with no line of sight between each other. A Bell inequality between those receivers is violated by more than four standard deviations, confirming the quality of the entanglement. This outdoor experiment represents a step toward satellite-based distributed quantum entanglement.

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## References

SHOWING 1-10 OF 18 REFERENCES

Practical free-space quantum key distribution over 1 km

- Physics
- 1998

A working free-space quantum key distribution system has been developed and tested over an outdoor optical path of {approximately}1 km at Los Alamos National Laboratory under nighttime conditions.…

Quantum communications in space

- Physics, EngineeringSPIE Optics + Photonics
- 2004

Coding data bits in the phase or polarization state of light allows us to exploit the wave particle duality for novel communication protocols. Using this principle the first practical quantum…

Violation of Bell Inequalities by Photons More Than 10 km Apart

- Physics
- 1998

A Franson-type test of Bell inequalities by photons 10.9 km apart is presented. Energy-time entangled photon pairs are measured using two-channel analyzers, leading to a violation of the inequalities…

Quantum Repeaters: The Role of Imperfect Local Operations in Quantum Communication

- Computer Science
- 1998

This work presents a scheme of a quantum repeater that connects a string of (imperfect) entangled pairs of particles by using a novel nested purification protocol, thereby creating a single distant pair of high fidelity.

New high-intensity source of polarization-entangled photon pairs.

- Physics, MedicinePhysical review letters
- 1995

Type-II noncollinear phase matching in parametric down conversion produces true entanglement: No part of the wave function must be discarded, in contrast to previous schemes.

Quantum cryptography with entangled photons

- Physics, MedicinePhysical review letters
- 2000

A novel key distribution scheme is implemented using Wigner's inequality to test the security of the quantum channel, and a variant of the BB84 protocol is realized.

Quantum cryptography based on Bell's theorem.

- Computer Science, MedicinePhysical review letters
- 1991

Practical application of the generalized Bells theorem in the so-called key distribution process in cryptography is reported. The proposed scheme is based on the Bohms version of the…

Quantum cryptography: A step towards global key distribution

- Computer Science, MedicineNature
- 2002

Absolutely secure key exchange between two sites has now been demonstrated over fibre and free-space optical links, marking a step towards accomplishing key exchange with a near-Earth orbiting satellite and hence a global key-distribution system.

Violation of Bell's Inequality under Strict Einstein Locality Conditions

- Physics
- 1998

We observe strong violation of Bell's inequality in an Einstein-Podolsky-Rosen-type experiment with independent observers. Our experiment definitely implements the ideas behind the well-known work by…

Proposed Experiment to Test Local Hidden Variable Theories.

- Physics
- 1969

A theorem of Bell, proving that certain predictions of quantum mechanics are inconsistent with the entire family of local hidden-variable theories, is generalized so as to apply to realizable…