October 2013
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Day October 23, 2013

Non-hermitian approach to decaying ultracold bosonic systems

S. Wimberger, C. A. Parra-Murillo, G. Kordas

A paradigm model of modern atom optics is studied, strongly interacting ultracold bosons in an optical lattice. This many-body system can be artificially opened in a controlled manner by modern experimental techniques. We present results based on a non-hermitian effective Hamiltonian whose quantum spectrum is analyzed. The direct access to the spectrum of the metastable many-body system allows us to easily identify relatively stable quantum states, corresponding to previously predicted solitonic many-body structures.

Pattern Formation and Solitons (nlin.PS); Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)

Conservative and PT-symmetric compactons in waveguide networks

A. V. Yulin, V. V. Konotop

Stable discrete compactons in arrays of inter-connected three-line waveguide arrays are found in linear and nonlinear limits in conservative and in parity-time PT symmetric models. The compactons result from the interference of the fields in the two lines of waveguides ensuring that the third (middle) line caries no energy. PT-symmetric compactons require not only the presence of gain and losses in the two lines of the waveguides but also complex coupling, i.e. gain and losses in the coupling between the lines carrying the energy and the third line with zero field. The obtained compactons can be stable and their branches can cross the branches of the dissipative solitons. Unusual bifurcations of branches of solitons from linear compactons are described.

Optics (physics.optics); Pattern Formation and Solitons (nlin.PS)