648 research outputs found
Bright solitons in Bose-Einstein condensates with field-induced dipole moments
We introduce an effectively one-dimensional (1D) model of a bosonic gas of
particles carrying collinear dipole moments which are induced by an external
polarizing field with the strength periodically modulated along the coordinate,
which gives rise to an effective nonlocal nonlinear lattice in the condensate.
The existence, shape and stability of bright solitons, appearing in this model,
are investigated by means of the variational approximation and numerical
methods. The mobility of solitons and interactions between them are studied
too.Comment: Journal of Physics B, in press. 20 pages, 9 figures (21 frames
Transmission of matter wave solitons through nonlinear traps and barriers
The transmissions of matter wave solitons through linear and nonlinear
inhomogeneities induced by the spatial variations of the trap and the
scattering length in Bose-Einstein condensates are investigated. New phenomena,
such as the enhanced transmission of a soliton through a linear trap by a
modulation of the scattering length, are exhibited. The theory is based on the
perturbed Inverse Scattering Transform for solitons, and we show that radiation
effects are important. Numerical simulations of the Gross-Pitaevskii equation
confirm the theoretical predictions.Comment: 6 pages, 4 figure
Scarring in a driven system with wave chaos
We consider acoustic wave propagation in a model of a deep ocean acoustic
waveguide with a periodic range-dependence. Formally, the wave field is
described by the Schrodinger equation with a time-dependent Hamiltonian. Using
methods borrowed from the quantum chaos theory it is shown that in the driven
system under consideration there exists a "scarring" effect similar to that
observed in autonomous quantum systems.Comment: 5 pages, 7 figure
Matter wave soliton bouncer
Dynamics of a matter wave soliton bouncing on the reflecting surface (atomic
mirror) under the effect of gravity has been studied by analytical and
numerical means. The analytical description is based on the variational
approach. Resonant oscillations of the soliton's center of mass and width,
induced by appropriate modulation of the atomic scattering length and the slope
of the linear potential are analyzed. In numerical experiments we observe the
Fermi type acceleration of the soliton when the vertical position of the
reflecting surface is periodically varied in time. Analytical predictions are
compared with the results of numerical simulations of the Gross-Pitaevskii
equation and qualitative agreement between them is found.Comment: 8 pages, 5 figure
Dissipative Dynamics of Matter Wave Soliton in Nonlinear Optical Lattice
Dynamics and stability of solitons in two-dimensional (2D) Bose-Einstein
condensates (BEC), with low-dimensional (1D) conservative plus dissipative
nonlinear optical lattices are investigated. In the case of focusing media
(with attractive atomic systems) the collapse of the wave packet is arrested by
the dissipative periodic nonlinearity. The adiabatic variation of the
background scattering length leads to metastable matter-wave solitons.
When the atom feeding mechanism is used, a dissipative soliton can exist in
focusing 2D media with 1D periodic nonlinearity. In the defocusing media
(repulsive BEC case) with harmonic trap in one dimension and one dimensional
nonlinear optical lattice in other direction, the stable soliton can exist.
This prediction of variational approach is confirmed by the full numerical
simulation of 2D Gross-Pitaevskii equation.Comment: 9 pages, 8 figure
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