Non-mean-field effects in systems with long-range forces in competition

Abstract

We investigate the canonical equilibrium of systems with long-range forces in competition. These forces create a modulation in the interaction potential and modulated phases appear at the system scale. The structure of these phases differentiate this system from monotonic potentials, where only the mean-field and disordered phases exist. With increasing temperature, the system switches from one ordered phase to another through a first-order phase transition. Both mean-field and modulated phases may be stable, even at zero temperature, and the long-range nature of the interaction will lead to metastability characterized by extremely long time scales.

Steering Matter Wave Superradiance with an Ultranarrow-Band Optical Cavity

“…Furthermore, the finite size of the pump beam should be accounted for, the radius of which is only a factor 2.5 larger than the radius of the BEC such that atoms at the edge of the BEC experience decreased values of ε p . Finite size effects leading to a Mie-scattering scenario may also be significant [37]. Another important issue in our experiment is collisional interaction, since due to the tight external trap the particle densities are well above 10 14 cm −3 .…”