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The defence will be in English.
Abstract: One-dimensional Josephson waveguides have generated significant interest in the fields of quantum technology and superconducting quantum information because they allow complete control over wave dispersion and nonlinear interactions. A variety of Josephson waveguides have been proposed and realized in the recent years, with applications ranging from near quantum-limited broadband amplification to multi-mode entanglement generation and non-reciprocal signals transmission. This thesis explores parametric interactions and entanglement generation in a novel architecture of Josephson waveguide. The latter consists of a high-pass microwave network and realizes an artificial material showing left-handed wave dispersion (or equivalently negative refractive index). The left-handed dispersion, combined with the Josephson nonlinearity, enables for various parametric processes, ranging from self-phase-matched broadband amplification of co-propagating modes to amplification and mixing of waves propagating in opposite directions. The realization of such Josephson waveguide opens new avenues within the framework of Josephson traveling wave parametric amplifiers and converters. Beyond these classical nonlinear optical processes, negative index Josephson waveguide are also powerful tools to generate nonclassical states of light such as broadband two-mode vacuum squeezed states and spatially separated entangled photon pairs. Here, we report about the measurements of such quantum states with this novel Josephson waveguide architecture, opening new perspectives for quantum sensing and quantum radar and illumination protocols, and more generally for microwave applications requiring the routing of entangled photons in different directions.
