11,510 research outputs found
Elastic Multi-Body Interactions on a Lattice
We show that by coupling two hyperfine states of an atom in an optical
lattice one can independently control two-, three-, and four-body on-site
interactions in a non-perturbative manner. In particular, under typical
conditions of current experiments one can have a purely three- or four-body
interacting gas of K atoms characterized by on-site interaction shifts
of several 100Hz.Comment: 6 pages, 3 figure
Three-Body Interacting Bosons in Free Space
We propose a method of controlling two- and three-body interactions in an
ultracold Bose gas in any dimension. The method requires us to have two coupled
internal single-particle states split in energy such that the upper state is
occupied virtually but amply during collisions. By varying system parameters
one can switch off the two-body interaction while maintaining a strong
three-body one. The mechanism can be implemented for dipolar bosons in the
bilayer configuration with tunnelling or in an atomic system by using
radio-frequency fields to couple two hyperfine states. One can then aim to
observe a purely three-body-interacting gas, dilute self-trapped droplets, the
paired superfluid phase, Pfaffian state, and other exotic phenomena.Comment: Published version with Supplemental Materia
Propagation of a Dark Soliton in a Disordered Bose-Einstein Condensate
We consider the propagation of a dark soliton in a quasi 1D Bose-Einstein
condensate in presence of a random potential. This configuration involves
nonlinear effects and disorder, and we argue that, contrarily to the study of
stationary transmission coefficients through a nonlinear disordered slab, it is
a well defined problem. It is found that a dark soliton decays algebraically,
over a characteristic length which is independent of its initial velocity, and
much larger than both the healing length and the 1D scattering length of the
system. We also determine the characteristic decay time.Comment: 4 pages, 2 figure
A ring trap for ultracold atoms
We propose a new kind of toroidal trap, designed for ultracold atoms. It
relies on a combination of a magnetic trap for rf-dressed atoms, which creates
a bubble-like trap, and a standing wave of light. This new trap is well suited
for investigating questions of low dimensionality in a ring potential. We study
the trap characteristics for a set of experimentally accessible parameters. A
loading procedure from a conventional magnetic trap is also proposed. The
flexible nature of this new ring trap, including an adjustable radius and
adjustable transverse oscillation frequencies, will allow the study of
superfluidity in variable geometries and dimensionalities.Comment: 4 figures, 10 pages ; the order of the sections has been changed ; to
appear in Phys. Rev.
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