A new class of all-optical Parametric Schroedinger-cats
S. Branca, F. De Martini, F. Mariani, Giovanni Di Giuseppe · 1999
The process of quantum-injection into an amplifier operating in a novel entangled configuration is adopted to “amplify” into a large dimensionality spin-12 Hilbert space the superposition properties of the entangled photon-couples generated by parametric down-conversion. The process is applied to the cases of mode-degenerate and mode non-degenerate Parametric Amplification. The quantum structure of the Wigner function and of the field correlation functions shows in both cases that the Schroedinger-cat behavior of the emitted field is largely detectable against the squeezed-vacuum noise. The absence of decoherence is explained in terms of a basic property of nonlinear complex systems.