111 research outputs found
Coupled Airy breathers
The dynamics of two component coupled Airy beams is investigated. In the
linear propagation regime a complete analytic solution describes breather like
propagation of the two components featuring non-diffracting self-accelerating
Airy behavior. The superposition of two beams with different input properties
opens the possibility to design more complex non-diffracting propagation
scenarios. In the strongly nonlinear regime the dynamics remains qualitatively
robust as is revealed by direct numerical simulations. Due to the Kerr effect
the two beams emit solitonic breathers, whose coupling period is compatible
with the remaining Airy-like beams. The results of this study are relevant for
the description of photonic and plasmonic beams propagating in coupled planar
waveguides as well as for birefrigent or multi-wavelengths beams
Dynamics of dipoles and vortices in nonlinearly-coupled three-dimensional harmonic oscillators
The dynamics of a pair of three-dimensional matter-wave harmonic oscillators
(HOs) coupled by a repulsive cubic nonlinearity is investigated through direct
simulations of the respective GrossPitaevskii equations (GPEs) and with the
help of the finite-mode Galerkin approximation (GA),which represents the two
interacting wave functions by a superposition of 3 + 3 HO p -wave
eigenfunctions with orbital and magnetic quantum numbers l = 1 and m = 1; 0; 1.
First, the GA very accurately predicts a broadly degenerate set of the system's
ground states in the p -wave manifold, in the form of complexes built of a
dipole coaxial with another dipole or vortex, as well as complexes built of
mutually orthogonal dipoles. Next, pairs of non-coaxial vortices and/or
dipoles, including pairs of mutually perpendicular vortices, develop remarkably
stable dynamical regimes, which feature periodic exchange of the angular
momentum and periodic switching between dipoles and vortices. For a moderately
strong nonlinearity, simulations of the coupled GPEs agree very well with
results produced by the GA, demonstrating that the dynamics is accurately
spanned by the set of six modes limited to l = 1.Comment: Physical Review E. In Pres
Soliton interaction mediated by cascaded four wave mixing with dispersive waves
We demonstrate that trapping of dispersive waves between two optical solitons
takes place when resonant scattering of the waves on the solitons leads to
nearly perfect reflections. The momentum transfer from the radiation to
solitons results in their mutual attraction and a subsequent collision. The
spectrum of the trapped radiation can either expand or shrink in the course of
the propagation, which is controlled by arranging either collision or
separation of the solitons
Nonlinearity-induced localization in a periodically-driven semi-discrete system
We demonstrate that nonlinearity plays a constructive role in supporting the
robustness of dynamical localization in a model which is discrete, in one
dimension and continuous in the orthogonal one. In the linear regime,
time-periodic modulation of the gradient strength along the discrete axis leads
to the usual rapid spread of an initially confined wave packet. Addition of the
cubic nonlinearity makes the dynamics drastically different, inducing robust
localization of moving wave packets. Similar nonlinearity-induced effects are
also produced by combinations of static and oscillating linear potentials. The
predicted nonlinearity-induced dynamical localization can be realized in
photonic lattices and Bose-Einstein condensates
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