45,882 research outputs found
Pulses and Snakes in Ginzburg--Landau Equation
Using a variational formulation for partial differential equations (PDEs)
combined with numerical simulations on ordinary differential equations (ODEs),
we find two categories (pulses and snakes) of dissipative solitons, and analyze
the dependence of both their shape and stability on the physical parameters of
the cubic-quintic Ginzburg-Landau equation (CGLE). In contrast to the regular
solitary waves investigated in numerous integrable and non-integrable systems
over the last three decades, these dissipative solitons are not stationary in
time. Rather, they are spatially confined pulse-type structures whose envelopes
exhibit complicated temporal dynamics. Numerical simulations reveal very
interesting bifurcations sequences as the parameters of the CGLE are varied.
Our predictions on the variation of the soliton amplitude, width, position,
speed and phase of the solutions using the variational formulation agree with
simulation results.Comment: 30 pages, 14 figure
QCD and spin effects in black hole airshowers
In models with large extra dimensions, black holes may be produced in
high-energy particle collisions. We revisit the physics of black hole formation
in extensive airshowers from ultrahigh-energy cosmic rays, focusing on
collisional QCD and black hole emissivity effects. New results for rotating
black holes are presented. Monte Carlo simulations show that QCD effects and
black hole spin produce no observable signatures in airshowers. These results
further confirm that the main characteristics of black hole-induced airshowers
do not depend on the fine details of micro black hole models.Comment: 6 pages, 2 figures, accepted for publication in Physical Review
Black holes and wormholes in AdS branes
In this work we have derived a class of geometries which describe black holes
and wormholes in Randall-Sundrum-type brane models, focusing mainly on
asymptotically anti-de Sitter backgrounds. We show that by continuously
deforming the usual four dimensional vacuum background, a specific family of
solutions is obtained. Maximal extensions of the solutions are presented, and
their causal structures are discussed.Comment: 7 pages, 4 figures. Published version in Physical Review
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