Classical Rotons in Cold Atomic Traps

Abstract

We predict the emergence of a roton minimum in the dispersion relation of elementary excitations in cold atomic gases in the presence of diffusive light. In large magneto-topical traps, multiple-scattering of light is responsible for the collective behavior of the system, which is associated to an effective Coulomb-like interaction between the atoms. In optically thick clouds, the re-scattered light undergoes diffusive propagation, which is responsible for a stochastic short-range force acting on the atoms. We show that the dynamical competition between these two forces results on a new polariton mode, which exhibits a roton minimum. Making use of Feynman's formula for the static structure factor, we show that the roton minimum is related to the appearance of long-range order in the system.

5 pages, 3 figures

References in corpus (7)

• Three-dimensional Roton-Excitations and Supersolid formation in Rydberg-excited Bose-Einstein Condensates
• Collective oscillations in ultracold atomic gases
• Correlational Origin of the Roton Minimum
• Self-driven nonlinear dynamics in magneto-optical traps
• A phonon laser in ultra-cold matter
• Driven collective instabilities in magneto-optical traps: a fluid-dynamical approach
• Rotons in interacting ultracold Bose gases

Cited by in corpus (6)

• Polytropic equilibrium and normal modes in cold atomic traps
• Bump-on-tail instability of twisted excitations in rotating cold atomic clouds
• Equation of state of a laser cooled gas
• Measuring the re-absorption cross section of a Magneto-Optical Trap
• The Dual Frequency Anisotropic Magneto-Optical Trap
• Roton-Induced Trapping in Strongly Correlated Rydberg Gases