QCS - Quantum Correlation in Space

In this experiment entangled photon pairs were created on La Palma, Spain. Then, one of these photons was sent to Tenerife, 144 km away. Additionally, random numbers were generated on both islands so that the way the correlations of the entangled photons were measured was independent of the photons. The spatial separation and timing of these actions was precisely arranged to show the counterintuitive nature of our world. Although this work does not completely rule out any "intuitive" theory it is the single most conclusive experiment of its type at the present time.

Short Description

Quantum mechanics makes a number of predictions, that are in stark contrast to our intuition of the world around us. The most essential ingredient of these counterintuitive predictions is entanglement (correlations between particles), a property of groups of particles that exists independent of their spatial and temporal separation.

Entanglement can be used to show that any 'intuitive' theory (where the properties of particles are well defined and interacting particles exchange some force) is not consistent with the world. Up to now no one has conclusively shown this.

Entanglement must also be tested over length scales far beyond current laboratory experiments to check the universal validity of quantum mechanics. The work presented here is an important stepping stone to a proposed Space-QUEST mission, which would utilise satellites to make such experiments possible.

The counterintuitive features of quantum mechanics are not only of theoretical interest, they can be used to for tasks, that would otherwise not be possible, most notably quantum cryptography (the sending of information in an absolutely secure way) and quantum computation (solving problems using quantum systems).

The technology created to complete this work can be used to directly aid research in these fields and also serves as a proof of principle for future experiments in space. Such experiments would both allow quantum tasks to be distributed throughout the world and also open the door for a new generation of experiments on a scale far beyond the capabilities of any earth- bound experiments.

The work presented here was possible due to a number of national and international collaborations and support, most notably with the help of the Austrian Research Promotion Agency (FFG).

Project Partners


Austrian Academy of Sciences, IQOQI Institute for Quantum Optics and Quantum Information - Rupert Ursin

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