Recent News

Multimode generation of quantum correlated photons using a crystal

The ability to distribute entanglement over long distances could be a key-enabling technology that will allow the large-scale deployment of quantum technologies. In our recent article published in Physical Review Letter and featured in Physics, we demonstrated an important step towards implementing a quantum repeater. Using our Europium doped crystal we produced streams of biphotons with one of the photon delayed up to 1 ms. This work shows that rare-earth crystals can be used to generate long-lived quantum correlations between spins and single photons, with a unique ability of temporal multiplexing that is important for increasing the speed of future quantum repeaters.



 

Quantifying high-dimensional entanglement with photons

Our paper demonstrating high-dimensional entanglement of photonics states was published in Physical Review Letters. We experimentally apply a new procedure for entanglement certification that is suitable for different physical systems. The method we developed is based on entanglement formation and allowed us to certify 4 bits of entanglement (or ebits) shared between two photons.

This work was done in collaboration with Nicolas Brunner from Geneva and Marcus Huber from Vienna.

 

Emerging Talents: Florian Fröwis

The Editorial Board of Journal of Physics A has selected Florian Fröwis to contribute to the special issue: Emerging Talents as part of the Journal of Physics series’ 50th anniversary celebrations in 2017. His paper “Lower bounds on the size of general Schrödinger-cat states from experimental data” was now published in this special issue.







 

Temporal multimode storage of entangled photons

Our paper demonstrating the multimode storage of two entangled photons in the solid-state quantum memory recently has been published in Physical Review Letters. Our results conclusively demonstrate the capability of the rare-earth ion doped crystals for future multiplexed quantum communication over the long distances.

This work was a collaboration between several groups, Nicolas Brunner and Marcus Huber here in Geneva on the theory side, and experimentally, Sae Woo Nam's group in NIST and Francesco Marsilli's group at JPL, whose superconducting single photon detectors we used for the experiment.