Stuttgart 2012 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 39: Quantengase: Wechselwirkungseffekte 2

Q 39.2: Talk

Thursday, March 15, 2012, 11:00–11:15, V7.01

Macroscopic quantum tunneling in Bose-Einstein condensates with long range 1/r-interaction — •Matin Kaufmann, Jörg Main, and Günter Wunner — 1. Institut für Theoretische Physik, Universität Stuttgart

The decay of Bose-Einstein condensates via macroscopic quantum tunneling is investigated in the case of spherical symmetry at zero temperature with the bounce trajectory formalism. The Gross-Pitaevskii equation is solved with a variational ansatz. To calculate the tunneling rate we must account for the fluctuations of the wave function and consider the stability of the bounce trajectory. Therefore we solve the Bogoliubov-de Gennes equations both for stationary wave functions and the bounce trajectory in imaginary time. Using an appropriate basis of fluctuations this method allows time efficient calculations of well converged Bogoliubov-de Gennes eigenvalues. This approach, however, is not restricted to wave functions obtained in a variational approximation and can be extended to full numerical grid computations.