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.

 

Сommenting on the famous Bell’s inequalities

PhysicsWorld.com publishes comments written by Prof. Nicolas Gisin about the new book "John Stewart Bell and Twentieth-Century Physics: Vision and Integrity" by Andrew Whitaker. While the debate over quantum theory between the supremely famous physicists, Albert Einstein and Niels Bohr, appeared to have become sterile in the 1930s, Bell was able to revive it and to make crucial advances - Bell's Theorem or Bell's Inequalities. The book describes not only his major contributions to quantum theory, but also his relatively humble origins and struggles to obtain secondary and university education.








 

Video - Guest Lecture Quantum key distribution in practice

In the recent video lecture Professor Nicolas Gisin and Dr. Matthieu Legré introduce to the practical implementations of Quantum Key Distribution in ID-Quantique and its commercialisation efforts. They explain the commercial side of Quantum Key Distribution (QKD), Quantum Random Number Generator (QRNG) and their impact for modern technologies.






 

TV Interview - La téléportation quantique

In an interview at Radio Télévision Suisse professor Nicolas Gisin, discusses the quantum teleportation phenomena and its influence to future quantum technologies.




 

High-Precision Measurement of the Dzyaloshinsky-Moriya Interaction between Two Rare-Earth Ions in a Solid

Our recent paper published in Physical Review Letters has been highlighted as an Editor's Suggestion. There we report on a direct measurement of the pairwise antisymmetric exchange interaction between two rare earth ions in a solid-state material. This interaction is also known as Dzyaloshinsky-Moriya interaction (DMI) and is fundamentally important magnetic phenomena.

To study it we measure electron spin resonance on Nd$^{3+}$ doped single crystals of YVO$_4$ to directly reveal the pairwise anti-symmetric exchange interaction or DMI.








 

Light-Matter Micro-Macro Quantum Correlations

Quantum mechanics predicts microscopic phenomena with undeniable success. Nevertheless, current theoretical and experimental efforts still do not yield conclusive evidence that there is or is not a fundamental limitation on the possibility to observe quantum phenomena at the macroscopic scale.

In a recent publication in Physical Review Letters, we report on the generation of entangled state which involves the superposition of two macroscopically distinguishable solid-state components composed of several tens of atomic excitations. Our experiment is clearly demonstrating micro-macro light-matter entanglement.