147 research outputs found
High temperature phase transition in the coupled atom-light system in the presence of optical collisions
The problem of photonic phase transition for the system of a two-level atomic
ensemble interacting with a quantized single-mode electromagnetic field in the
presence of optical collisions (OC) is considered. We have shown that for large
and negative atom-field detuning a photonic field exhibits high temperature
second order phase transition to superradiant state under thermalization
condition for coupled atom-light states. Such a transition can be connected
with superfluid (coherent) properties of photon-like low branch (LB)
polaritons. We discuss the application of metallic cylindrical waveguide for
observing predicted effects.Comment: 8 pages, 2 figure
Noise-induced topological transformations of vortex solitons in optical fibers filled with a cold atomic gas
We consider the influence of optical and temperature-dependent atomic
fluctuations on the formation and propagation of optical vortex solitons in
dense media realized as hollow-core optical fibers filled with a cold atomic
gas in presence of optical pumping. We show different perturbation-induced
scenaria of complete destruction and smooth transformations of the topological
characteristics of localized optical structures in hollow-core fiber. The
maximum levels of optical and atomic fluctuations at which the soliton regime
can be maintained has been determined. The estimates for these levels show an
opportunity to observe the optical vortex solitions in the core-filling gas of
the fiber for temperatures smaller than the critical temperature for
Bose-Einstein condensate.Comment: 12 pages, 10 EPS figures, submitted to Physical Review
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