1203.3831 (Marco G. Genoni et al.)

Driving linear systems towards non-classical states with the help of
noise    [PDF]

Marco G. Genoni, Stefano Mancini, Alessio Serafini

We study the possibility of taking bosonic systems subject to quadratic Hamiltonians and a noisy thermal environment to non-classical stationary states by weak Gaussian measurements and conditioned linear driving. We derive general analytical upper bounds for the single mode squeezing and multimode entanglement at steady state, depending only on the Hamiltonian parameters and on the number of thermal excitations of the bath. Our findings show that, rather surprisingly, larger number of thermal excitations in the bath allow for larger steady-state squeezing and entanglement if the efficiency of the Gaussian measurements conditioning the feedback loop is high enough. Such efficiencies are included in our exact treatment, which allows us to determine efficiency thresholds for the noise-enhancement of quantum resources to take place.

View original: http://arxiv.org/abs/1203.3831