# Free-Space distribution of entanglement and single photons over 144 km

@article{Ursin2006FreeSpaceDO, title={Free-Space distribution of entanglement and single photons over 144 km}, author={Rupert Ursin and F. Tiefenbacher and Tobias Schmitt-Manderbach and Henning Weier and Thomas Scheidl and Michael Lindenthal and Bibiane Blauensteiner and Thomas Jennewein and Josep Perdigues and Pavel Trojek and B. Oemer and Martin Fuerst and Michael Meyenburg and John G. Rarity and Zoran Sodnik and Cesare Barbieri and Harald Weinfurter and Anton Zeilinger}, journal={Nature Physics}, year={2006} }

Quantum Entanglement is the essence of quantum physics and inspires fundamental questions about the principles of nature. Moreover it is also the basis for emerging technologies of quantum information processing such as quantum cryptography, quantum teleportation and quantum computation. Bell's discovery, that correlations measured on entangled quantum systems are at variance with a local realistic picture led to a flurry of experiments confirming the quantum predictions. However, it is still…

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## References

SHOWING 1-10 OF 33 REFERENCES

### Experimental free-space distribution of entangled photon pairs over 13 km: towards satellite-based global quantum communication.

- PhysicsPhysical review letters
- 2005

The distributed entangled photon source is exploited to demonstrate the Bennett-Brassard 1984 quantum cryptography scheme and the distribution distance achieved is for the first time well beyond the effective thickness of the aerosphere, hence presenting a significant step towards satellite-based global quantum communication.

### Experimental Free-Space Distribution of Entangled Photon Pairs over a Noisy Ground Atmosphere of 13km

- Physics
- 2004

We report free-space distribution of entangled photon pairs over a noisy ground atmosphere of 13km. It is shown that the desired entanglement can still survive after the two entangled photons have…

### Deterministic quantum teleportation of atomic qubits

- PhysicsNature
- 2004

Un unconditional teleportation of massive particle qubits using atomic (9Be+) ions confined in a segmented ion trap is reported, which achieves an average fidelity of 78 per cent, which exceeds the fidelity of any protocol that does not use entanglement.

### Proof-of-concept experiments for quantum physics in space

- PhysicsSPIE Optics + Photonics
- 2004

Quantum physics experiments in space using entangled photons and satellites are within reach of current technology. We propose a series of fundamental quantum physics experiments that make…

### Security of quantum key distribution with entangled photons against individual attacks

- Computer Science, Physics
- 2002

A proof of security which applies to realistic sources, and to untrustable sources which can be placed outside the labs of the two receivers, is presented, and it is shown that BBM92 has potential for much longer communication distances, up to 170 km, in the presence of realistic experimental imperfections.

### Experimental demonstration of quantum correlations over more than 10 km

- Physics
- 1998

Energy and time entangled photons at a wavelength of 1310 nm are produced by parametric down-conversion in a ${\mathrm{KNbO}}_{3}$ crystal and are sent into all-fiber interferometers using a…

### Experimental quantum teleportation

- PhysicsNature
- 1997

It is shown that during teleportation, one of a pair of entangled photons are subjected to a measurement such that the second photon of the entangled pair acquires the polarization of the initial photon.

### Quantum computation

- Physics
- 1996

The theory of quantum computation can be constructed from the abstract study of anyonic systems. In mathematical terms, these are unitary topological modular functors. They underlie the Jones…

### Quantum cryptography with entangled photons

- Computer Science, PhysicsPhysical 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.

### Long-Distance Free-Space Distribution of Quantum Entanglement

- PhysicsScience
- 2003

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…