Środowiskowe Seminarium z Informacji i Technologii Kwantowych

Squeezing is the leading strategy to achieve quantum-enhanced precision measurements and entanglement in atomic and optical experiments today. By characterizing the nonclassical features through average values and variances of linear observables, squeezing can be exploited with simple measurements but applications are limited to Gaussian states. Here we show how squeezing, i.e., the reduction of quantum fluctuations, of optimally chosen nonlinear observables captures the metrological properties and the entanglement of highly sensitive non-Gaussian states. We further show how squeezing of multimode systems can achieve quantum enhancements in multiparameter estimation problems and leads to accessible lower bounds on the quantum Fisher matrix.