onlinear squeezing as a non-Gaussian resource for quantum technologies

Quantum non-Gaussianity was recently recognized as an important resource for CV quantum information processing, which is necessary for some of the advanced applications, such as quantum computation. The non-Gaussian features of quantum states, often tied to negativity of their  igner function, are difficult to implement experimentally. The most common experimental sources rely on photon number resolving measurements or interactions with qubit systems, which are both probabilistic approaches. In past we have suggested that one of the elementary non-Gaussian operations, cubic phase gate, can be realized deterministically in a measurement induced fashion if a proper ancillary quantum state is used. This ancillary state possesses a novel kind of non-Gaussianity - the nonlinear squeezing - defined as reduction of variance of a nonlinear combination of quadrature operators. In contrast to vague indicators of non-Gaussianity such as the negativity of Wigner function which is only necessary, the nonlinear squeezing is a sufficient operationally defined quantifier of non-Gaussianity that is directly tied to the performance of the deterministic non-Gaussian circuit. In this talk we present the basic theoretical concept and elementary behavior, several theoretical methods of preparation for quantum states with nonlinear squeezing, and the recent progress in experimental realization.