Hamburg 2009 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 51: Quantengase: Gitter und Tunneln II
Q 51.2: Talk
Thursday, March 5, 2009, 16:45–17:00, Audi-A
Controlling the Landau-Zener decay in a Bose-Einstein condensate realization of the Wannier-Stark problem — •Ghazal Tayebirad1,2, Alessandro Zenesini3, Hans Lignier3, Donatella Ciampini3, Jagoda Radogostowicz3, Oliver Morsch3, Ennio Arimondo3, and Sandro Wimberger1,2 — 1Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg — 2Heidelberg Graduate School of Fundamental Physics, Albert-Ueberle-Str. 3-5, 69120 Heidelberg — 3Dipartimento di Fisica, Unversità degli Studi di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
A comprehensive study of the tunneling dynamics of a Bose-Einstein condensate (BEC) in a tilted periodic potential is presented. This system enjoys a continuing popularity in many experimental groups [1]. In excellent agreement with experiments, our theoretical calculations, based on a mean-field theory for a many-particle condensate, explain the temporal behavior of the Landau-Zener (LZ) tunneling. While for a typical initial state of a BEC being strongly localized in momentum space, we observe a step-like structure in the survival probability as a function of time (resembling periodic Bloch oscillations), these structures are gradually washed out by increasing either the initial width in momentum space or the atom-atom interactions, together with other observed time-dependent structures in the profile of the survival probability, this clarifies to what extend we can expect deviation from a purely exponential decay in the studied LZ tunneling process.
[1] T. Schulte et al., Phys. Rev. A, 77, 023610 (2008); C. Sias et al., Phys. Rev. Lett. 98, 120403 (2007)