196 research outputs found
Multichannel oscillations and relations between LSND, KARMEN and MiniBooNE, with and without CP violation
We show by examples that multichannel mixing can affect both the parameters
extracted from neutrino oscillation experiments, and that more general
conclusions derived by fitting the experimental data under the assumption that
only two channels are involved in the mixing. Implications for MiniBooNE are
noted and an example based on maximal CP violation displays profound
implications for the two data sets (muon-neutrino and muon-antineutrino) of
that experiment.Comment: 5 pages 4 figure
Scattering of dipole-mode vector solitons: Theory and experiment
We study, both theoretically and experimentally, the scattering properties of
optical dipole-mode vector solitons - radially asymmetric composite
self-trapped optical beams. First, we analyze the soliton collisions in an
isotropic two-component model with a saturable nonlinearity and demonstrate
that in many cases the scattering dynamics of the dipole-mode solitons allows
us to classify them as ``molecules of light'' - extremely robust spatially
localized objects which survive a wide range of interactions and display many
properties of composite states with a rotational degree of freedom. Next, we
study the composite solitons in an anisotropic nonlinear model that describes
photorefractive nonlinearities, and also present a number of experimental
verifications of our analysis.Comment: 8 pages + 4 pages of figure
Modulational instability, solitons and beam propagation in spatially nonlocal nonlinear media
We present an overview of recent advances in the understanding of optical
beams in nonlinear media with a spatially nonlocal nonlinear response. We
discuss the impact of nonlocality on the modulational instability of plane
waves, the collapse of finite-size beams, and the formation and interaction of
spatial solitons.Comment: Review article, will be published in Journal of Optics B, special
issue on Optical Solitons, 6 figure
Linear and nonlinear waveguides induced by optical vortex solitons
We study, numerically and analytically, linear and nonlinear waveguides
induced by optical vortex solitons in a Kerr medium. Both fundamental and
first-order guided modes are analyzed, as well as the cases of effectively
defocusing and focusing nonlinearity.Comment: 3 pages, 3 figures, changed conten
Interaction of matter-wave gap solitons in optical lattices
We study mobility and interaction of gap solitons in a Bose-Einstein
condensate (BEC) confined by an optical lattice potential. Such localized
wavepackets can exist only in the gaps of the matter-wave band-gap spectrum and
their interaction properties are shown to serve as a measure of discreteness
imposed onto a BEC by the lattice potential. We show that inelastic collisions
of two weakly localized near-the-band-edge gap solitons provide simple and
effective means for generating strongly localized in-gap solitons through
soliton fusion.Comment: 12 pages, 7 figure
Stable higher-charge discrete vortices in hexagonal optical lattices
We show that double-charge discrete optical vortices may be completely stable
in hexagonal photonic lattices where single-charge vortices always exhibit
dynamical instabilities. Even when unstable the double-charge vortices
typically have a much weaker instability than the single-charge vortices, and
thus their breakup occurs at longer propagation distances
Two dimensional modulational instability in photorefractive media
We study theoretically and experimentally the modulational instability of
broad optical beams in photorefractive nonlinear media. We demonstrate the
impact of the anisotropy of the nonlinearity on the growth rate of periodic
perturbations. Our findings are confirmed by experimental measurements in a
strontium barium niobate photorefractive crystal.Comment: 8 figure
Solitons in one-dimensional nonlinear Schr\"{o}dinger lattices with a local inhomogeneity
In this paper we analyze the existence, stability, dynamical formation and
mobility properties of localized solutions in a one-dimensional system
described by the discrete nonlinear Schr\"{o}dinger equation with a linear
point defect. We consider both attractive and repulsive defects in a focusing
lattice. Among our main findings are: a) the destabilization of the on--site
mode centered at the defect in the repulsive case; b) the disappearance of
localized modes in the vicinity of the defect due to saddle-node bifurcations
for sufficiently strong defects of either type; c) the decrease of the
amplitude formation threshold for attractive and its increase for repulsive
defects; and d) the detailed elucidation as a function of initial speed and
defect strength of the different regimes (trapping, trapping and reflection,
pure reflection and pure transmission) of interaction of a moving localized
mode with the defect.Comment: 12 pages, 10 figure
Quadratic solitons as nonlocal solitons
We show that quadratic solitons are equivalent to solitons of a nonlocal Kerr
medium. This provides new physical insight into the properties of quadratic
solitons, often believed to be equivalent to solitons of an effective saturable
Kerr medium. The nonlocal analogy also allows for novel analytical solutions
and the prediction of novel bound states of quadratic solitons.Comment: 4 pages, 3 figure
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