Marek Trippenbach

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We identify all possible classes of solutions for two-component Bose-Einstein condensates (BECs) within the Thomas-Fermi (TF) approximation, and check these results against numerical simulations of the coupled Gross-Pitaevskii equations (GPEs). We find that they can be divided into two general categories. The first class contains solutions with a region of(More)
We predict a sharp crossover from nonlinear self-defocusing to discrete self-trapping of a narrow Gaussian beam with the increase of the refractive index contrast in a periodic photonic lattice. We demonstrate experimentally nonlinear discrete localization of light with defocusing nonlinearity by single site excitation in LiNbO(3) waveguide arrays.
We propose a scheme for stabilizing spatiotemporal solitons (STSs) in media with cubic self-focusing nonlinearity and "dispersion management," i.e., a layered structure inducing periodically alternating normal and anomalous group-velocity dispersion. We develop a variational approximation for the STS, and verify results by direct simulations. A stability(More)
We study the coherence properties of an atom laser, which operates by extracting atoms from a gaseous Bose-Einstein condensate via a two-photon Raman process, by analyzing a recent experiment [(Hagley et al., submitted to Phys. Rev. Lett. (1999)]. We obtain good agreement with the experimental data by solving the time-dependent Gross-Pitaevskii equation in(More)
We consider a two-dimensional ͑2D͒ nonlinear Schrödinger equation with self-focusing nonlinearity and a quasi-1D double-channel potential, i.e., a straightforward 2D extension of the well-known double-well potential. The model may be realized in terms of nonlinear optics and Bose-Einstein condensates. The variational approximation ͑VA͒ predicts a(More)
We consider effects of interspecies attraction on two-component gap solitons ͑GSs͒ in the binary BEC with intraspecies repulsion, trapped in the one-dimensional optical lattice ͑OL͒. Systematic simulations of the coupled Gross-Pitaevskii equations corroborate an assumption that, because the effective mass of GSs is negative, the interspecies attraction may(More)
We investigate the stability properties of breather solitons in a three-dimensional Bose-Einstein condensate with Feshbach resonance management of the scattering length and confined only by a one-dimensional optical lattice. We compare regions of stability in parameter space obtained from a fully 3D analysis with those from a quasi-two-dimensional(More)
We study stationary states of a two-dimensional ͑2D͒ Bose-Einstein condensate with both attractive and repulsive nonlinearities in a combination of a double-square-well potential in one direction and a perpendicular optical lattice. We look for dual-core solitons in this configuration, focusing on their symmetry-breaking bifurcations. For attractive(More)
Variational methods have become a widely used tool in the search for solitary waves in nonlinear systems. If a system exhibits fast oscillations in one of the degrees of freedom, its wavefunction can split into two or more separate parts and 'orthodox' variational descriptions are inadequate to include such nontrivial dynamics. A candidate for somewhat more(More)