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Localization of waves in space and particle-like properties under
collisions constitute the fascinating phenomena that led to the notion
of a soliton. How much of the classical particle-like properties of
solitons remain for the matter-wave solitons that can be studied with
Bose-Einstein condensates? In this poster we discuss how bright
matter-wave solitons can acquire dissipative and non-classical
properties.
Matter-wave bright solitons are predicted to reflect from a purely attractive potential well although they are macroscopic objects with classical particle-like properties[1]. The non-classical reflection occurs at small velocities and a pronounced switching to almost perfect transmission above a critical velocity is found, caused by nonlinear mean-field interactions. Full numerical results from the nonlinear Schroedinger equation are complimented by a two-mode variational calculation to explain the predicted effect, which can be used for velocity filtering of solitons. The experimental realization with laser-induced potentials or two-component Bose-Einstein condensates is suggested. In the second part of the poster we consider the motion of a matter-wave bright soliton under the influence of a cloud of thermal particles[2]. In the ideal one-dimensional system, the scattering process of the quasiparticles with the soliton is reflectionless; however, the quasiparticles acquire a phase shift. In the realistic system of a Bose-Einstein condensate confined in a tight waveguide trap, the transverse degrees of freedom generate an extra nonlinearity in the system which gives rise to finite reflection and leads to dissipative motion of the soliton. We calculate the velocity and temperature-dependent frictional force and diffusion coefficient of a matter-wave bright soliton immersed in a thermal cloud. [1] Ch. Lee and J. Brand Enhanced quantum reflection of matter-wave solitons Europhys. Lett. 73, 321 (2006) [2] S. Sinha, A. Yu. Cherny, D. Kovrizhin, and J. Brand Friction and diffusion of matter-wave bright solitons Phys. Rev. Lett. 96, 030406 (2006) |
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