Abstract

Noise-sustained patterns have been recently predicted in several systems including a Kerr cavity and an optical parametric oscillator [1] In these systems a regime of convective instability can appear, in which a transverse pattern arises as a macroscopic manifestation of amplified and spatially structured quantum noise, with magnification factors of several order of magnitudes. These noise-sustained structures are interesting candidates for the study of quantum correlations at a macroscopic level. However, standard methods to calculate quantum fluctuations are not helpful in this situation. Linearization schemes, usually invoked to use a positive-definite Wigner distribution, can not be applied since the reference state is unstable and fluctuations are amplified. The use of a P-positive representation is also not useful because of trajectories which diverge from the reference unstable state. An alternative that we explore here is the use of the Q-representation.

© 2000 IEEE