Manipulating information at the quantum level is profoundly different from manipulating it classically. This opens the door to some new and surprising applications such as quantum cryptography (in which the security of the encryption of a message is guaranteed by the laws of physics) or quantum computers (which could solve certain problems such as factoring exponentially faster than classical computers). The Laboratoire d’Information Quantique (LIQ) is actively working on different aspects quantum information, both at the theoretical and experimental level. 

Theory

Our theoretical work deals with many aspects of quantum information, including: quantum state estimation, quantum cloning, quantum non-locality and communication complexity, quantum cryptography, and quantum coin tossing. We are also interested in the foundations of quantum physics, in particular the interpretation of measurements of energy and the nature of time in quantum theory. Recently, we have developed the concept of "device-independent information processing" in which the correct functioning of a quantum protocol is certified by the violation of a Bell inequality. On the more mathematical side, we have developed non-commutative polynomial optimization techniques for quantum information and quantum physics. 

Experimental Quantum Optics

We also work on the experimental implementation of the theoretical ideas of quantum information. Earlier results include the realization of an all fiber demonstration of the Deutsch-Jozsa and Bernstein-Vazirani algorithms, an all fiber demonstration of error filtration for quantum communication, and the first provably secure demonstration of quantum coin tossing. Present work is focusing on the development of novel sources of entangled photons, both in fibers and in silicon waveguides; as well as the manipulation of entangled photons in the frequency domain. 

Reservoir Computing and other research topics

In addition to quantum information, our group also works on some other topics. Most notably these include the experimental realization of (classical) analog information processing systems based on the concept of “reservoir computing”. This is a new computation paradigm which has proved very successful within the artificial intelligence and machine learning community.

 

For more details on our research topics, see our list of publications.

None of this would be possible without financial support.