8 research outputs found
Fragmentation, domain formation and atom number fluctuations of a two-species Bose-Einstein condensate in an optical lattice
We theoretically study the loading of a two-species Bose-Einstein condensate
to an optical lattice in a tightly-confined one-dimensional trap. Due to
quantum fluctuations the relative inter and intra species phase coherence
between the atoms and the on-site atom number fluctuations are reduced in the
miscible regime. For the immiscible case the fluctuations are enhanced and the
atoms form metastable interleaved spatially separated domains where the domain
length and its fluctuations are affected by quantum fluctuations.Comment: 32 page
Quantum dynamics of atomic bright solitons under splitting and re-collision, and implications for interferometry
We numerically study the classical and quantum dynamics of an atomic bright
soliton in a highly-elongated one-dimensional harmonic trap with a Gaussian
barrier. In the regime of the recent experiment by Dyke {\it et al.}, the
system realizes a coherent nonlinear soliton beam-splitter and interferometer
whose accuracy we analyze. In the case of tighter radial trap confinement and
enhanced quantum fluctuations, a split soliton can represent a spin-squeezed,
or alternatively, a fragmented condensate with reduced phase-coherence that can
be measured by interfering the split soliton by the barrier. We also find large
quantum mechanical uncertainties in the soliton's position and momentum due to
nonlinear interaction with the barrier.Comment: 30 pages, 9 figures. Modified in response to referees' comments, and
with additional simulation result
Effects of interatomic collisions on atom laser outcoupling
We present a computational approach to the outcoupling in a simple
one-dimensional atom laser model, the objective being to circumvent
mathematical difficulties arising from the breakdown of the Born and Markov
approximations. The approach relies on the discretization of the continuum
representing the reservoir of output modes, which allows the treatment of
arbitrary forms of outcoupling as well as the incorporation of non-linear terms
in the Hamiltonian, associated with interatomic collisions. By considering a
single-mode trapped condensate, we study the influence of elastic collisions
between trapped and free atoms on the quasi steady-state population of the
trap, as well as the energy distribution and the coherence of the outcoupled
atoms.Comment: 25 pages, 11 figures, to appear in J. Phys.
Theory of Multidimensional Solitons
We review a number of topics germane to higher-dimensional solitons in
Bose-Einstein condensates. For dark solitons, we discuss dark band and planar
solitons; ring dark solitons and spherical shell solitons; solitary waves in
restricted geometries; vortex rings and rarefaction pulses; and multi-component
Bose-Einstein condensates. For bright solitons, we discuss instability,
stability, and metastability; bright soliton engineering, including pulsed atom
lasers; solitons in a thermal bath; soliton-soliton interactions; and bright
ring solitons and quantum vortices. A thorough reference list is included.Comment: review paper, to appear as Chapter 5a in "Emergent Nonlinear
Phenomena in Bose-Einstein Condensates: Theory and Experiment," edited by P.
G. Kevrekidis, D. J. Frantzeskakis, and R. Carretero-Gonzalez
(Springer-Verlag