Optical Gaussian entangled states can be generated deterministically, up to very large number of modes. Furthermore, for nontrivial quantum computation, non-Gaussianity is required, which can be obtained for instance from photon subtraction. We will explore here the controlled generation of multimode graph states from ultrafast optical pulses (optical frequency combs) and parametric down conversion in a synchronously pumped cavity, and how they can be applied to measurement based quantum computation. Mode dependent photon subtraction is then implemented through sum-frequency generation, and characterization is performed through frequency resolved homodyne detection. We study the influence of a non Gaussian ingredient on a Gaussian graph state, from fundamental considerations to its applicability to quantum information protocols.

报告人简介：Nicolas Treps is a full professor at Sorbonne Université. He did his PhD with Claude Fabre at Laboratoire Kastler Brossel on Quantum Imaging, and then went for a post-doc at the Australian National University with Ping-Koy Lam and Hans Bachor on quantum information protocols with squeezed light. He developed modal analysis of multimode quantum light, which lead to pioneering experiments on quantum metrology, quantum imaging and multimode quantum information. His research is now centered on quantum metrology and quantum information with optical frequency combs. Focusing on the continuous variable regime, he develops novel approaches to measurement based quantum computing and parameter estimation. He also applied these concepts to the study of ultrafast laser dynamics and spatial multiplexing. This lead to the co-foundation of Cailabs Start-up Company, that develops a complete imaging system with applications to spatial multiplexing in optical fibre and high power laser welding. He co-authored 2 books and over 100 refereed publications.