Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 55: Transport and Localization of interacting Bosons 2
Q 55.2: Vortrag
Donnerstag, 17. März 2011, 14:45–15:00, BAR Schön
Stability and decay of Bloch oscillations in Bose-Einstein condensates with time-dependent atom-atom interactions — •Christopher Gaul1, Elena Díaz1,2, Cord A. Müller3, Rodrigo Lima4, and Francisco Domínguez-Adame1 — 1GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid, Spain — 2Institute for Materials Science, Technische Universität Dresden, D-01062 Dresden, Germany — 3Centre for Quantum Technologies, National University of Singapore, Singapore 117543, Singapore — 4Instituto de Física, Universidade Federal de Alagoas, Maceió AL 57072-970, Brazil
Bose-Einstein condensates in tilted optical lattices allow the observation of Bloch oscillations (BOs). Generically, the interaction leads to dephasing and to the decay of the wave packet. By means of Feshbach resonances, however, experimentalists can tune the s-wave scattering length to zero or modulate it in time. We investigate the effect of such time-managed interactions on BOs. Additionally to the noninteracting case and a solitonic solution, we find an infinite family of modulations that preserve the Bloch oscillating wave packet [1]. In these cases, the stability follows from a time-reversal argument. In the unstable cases, we employ a collective-coordinates ansatz and a stability analysis, in order to quantify the decay of the BOs. In particular we show that in presence of external perturbations, an additional modulation of the interaction can enhance the lifetime of the Bloch oscillation [2].
[1] Gaul et al. PRL 102, 255303 (2009)
[2] Díaz et al. PRA 81, 051607R (2010)