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Université de Lille
Laboratoire

New states of light : from quantum to nonlinear regime

We delve into an experimental exploration of the propagation of an optical intensity jump discontinuity within a nonlocal stochastic Kerr focusing nematic liquid crystal cell. Our investigation, both theoretical and experimental, unveils the pivotal role of nonlocality in paving the way for beam steering within our system. Remarkably, we observe that the trajectory of the discontinuity bends in response to the injected power, a phenomenon elucidated through both theoretical predictions and experimental validation. Despite the inherent stochastic nature of the medium and the persistent transverse instabilities, our findings reveal the resilience of a focusing shocklike dynamics, underscoring the robustness of the observed phenomena [Phys. Rev. E 103 (2021)].

We present a novel distance-based metric designed to assess the nonclassicality of bosonic field states, offering superior performance compared to existing measures. Our approach hinges on quantifying the operator ordering sensitivity of the state, which gauges its responsiveness to variations in operator ordering manifested through the Renyi entropy of quasiprobabilities and the oscillations in its Wigner function. By meticulously controlling the operator ordering sensitivity of classical states, we gain precise geometric insights into their positioning within the density matrix space, enabling the formulation of a distance-based nonclassicality measure. Through an in-depth analysis, we elucidate the distinction between this measure and a recently proposed quantum macroscopicity metric, highlighting their unique conceptual underpinnings.