Search results for "online"
showing 10 items of 4526 documents
Observation of classical optical wave condensation
2010
We demonstrate the nonlinear condensation of classical optical waves. The condensation is observed directly, as a function of nonlinearity and wave kinetic energy, in a self-defocusing photorefractive crystal.
Generalization of Vinen’s equation including transition to superfluid turbulence
2005
A phenomenological generalization of the well known Vinen equation for the evolution of vortex line density in superfluid counterflow turbulence is proposed. This generalization includes nonlinear production terms in the counterflow velocity and corrections depending on the diameter of the tube. The equation provides a unified framework for the various phenomena (stationary states and transitions) present in counterflow superfluid turbulence: in fact, it is able to describe the laminar regime, the first-order transition from laminar to turbulent TI state, the two turbulent states, the transition from TI to TII turbulent states, and it yields a slower decay of the counterflow turbulence than…
Subdiffractive solitons in bose-einstein condensates
2005
We predict the disappearance of diffraction (the increase of the mass) of Bose-Einstein condensates in counter-moving periodic potentials. We demonstrate subdiffractive solitons (stable droplets of the condensate) in the vicinity of this zero diffraction point.
Slow-light soliton dynamics with relaxation
2007
We solved the problem of soliton dynamics in the presence of relaxation. We demonstrate that the spontaneous emission of atoms is strongly suppressed due to nonlinearity. The spatial shape of the soliton is well preserved.
Solitons and their observable signatures in quasi-one-dimensional systems
2005
We give an overview of the experimental signatures of nonlinear waves: notably topological and non topological solitons, in specific quasi-one-dimensional devices and condensed matter systems. Non topological solitons can be easily observed and manipulated, on a macroscopic scale, in optical fibers and electrical transmission lines. Topological solitons have been clearly identified as fluxons in Josephson transmission lines and as domain walls in condensed matter systems such as magnetic chains and synthetic polymers. By contrast, at the present time the observable signatures of nonlinear excitations such as pulse or envelope solitons and polarons, which are predicted to occur on a microsco…
Towards nonlinear optics with cold Rydberg atoms inside a hollow core fiber
2015
We present an experimental setup for studying strongly nonlinear light-matter interactions using cold atoms inside a hollow core fiber. A Rydberg EIT process can potentially be used to generate strong and tunable effective photon-photon interactions.
Integrability of an inhomogeneous nonlinear Schrödinger equation in Bose–Einstein condensates and fiber optics
2010
In this paper, we investigate the integrability of an inhomogeneous nonlinear Schrödinger equation, which has several applications in many branches of physics, as in Bose-Einstein condensates and fiber optics. The main issue deals with Painlevé property (PP) and Liouville integrability for a nonlinear Schrödinger-type equation. Solutions of the integrable equation are obtained by means of the Darboux transformation. Finally, some applications on fiber optics and Bose-Einstein condensates are proposed (including Bose-Einstein condensates in three-dimensional in cylindrical symmetry).
Bremsstrahlung from a repulsive potential: attosecond pulse generation
2008
The collision of an electron against a repulsive potential in the presence of a laser field is investigated. It is found that a sufficiently strong laser field forces the electron to remain in the neighbourhood of the repulsive potential causing bremsstrahlung. By appropriately filtering the emitted signal, an electron in the presence of a repulsive potential is capable of generating attosecond pulses.
W-shaped, bright and kink solitons in the quadratic-cubic nonlinear Schrödinger equation with time and space modulated nonlinearities and potentials
2017
An extended non-linear Schrodinger equation (NLSE) combining quadratic and cubic Non-linearities, which appears as an approximate model of a relatively dense quasi-one-dimensional Bose–Einstein con...
Vortex replication in Bose-Einstein condensates trapped in double-well potentials
2009
In this work we demonstrate, by means of numerical simulations, the possibility of replicating matter-wave vortices in a Bose-Einstein condensate trapped in a double-well potential. The most remarkable result is the generation of replicas of an initial vortex state located in one side of the double potential, which evolves into two copies, each one located in one of the potential minima. A simple linear theory gives the basic explanation of the phenomenon and predicts experimental realistic conditions for observation. A complementary strategy of easy experimental implementation to dramatically decrease the replication time is presented and numerically tested for the general case of nonlinea…