Speaker
Prof.
Axel Griesmaier
(University of Stuttgardt, Germany)
Description
In my talk I will try to to shine a light on the peculiar
stability conditions of dipolar Bose-Einstein
condensates trapped in 1D optical lattices. All effects
connected with the formation of ordered states in
dipolar quantum gases appear close to the border
between stability and instability of the trapped gas.
These features are mediated by the interplay between
short-range and long-range, isotropic and anisotropic
interactions and the trap. Due to the anisotropy of
dipole-dipole interaction, the stability properties are in
fact strongly affected by the confining potential.
We have experimentally studied these stability
conditions for various scenarios with a dipolar 52Cr
Bose-Einstein condensate, especially in the relevant
case of periodic 1D lattice potentials where we observe
that inter-sites effects play an important role. A 1D
lattice, in contrast to a purely contact interacting gas,
induces a crossover from a dipolar de-stabilization to a
dipolar stabilized regime with increasing lattice depth.
In a deep lattice, a dipolar condensate can be stabilized
even at large negative scattering length in the
interaction-dominated regime. As an important
consequence, a dipolar condensate can be stable in
trap but immediately collapse as soon as the external
confinement is removed. This characteristic feature of
strongly dipolar BECs makes the usual mapping from
time-of flight measurements on the momentum
distribution highly non-trivial.
Primary author
Prof.
Axel Griesmaier
(University of Stuttgardt, Germany)
