Issue
EPL
Volume 77, Number 4, February 2007
Article Number 40005
Number of page(s) 5
Section General
DOI http://dx.doi.org/10.1209/0295-5075/77/40005
Published online 06 February 2007
EPL, 77 (2007) 40005
DOI: 10.1209/0295-5075/77/40005

Driven collective quantum tunneling of ultracold atoms in engineered optical lattices

R. Khomeriki1, 2, S. Ruffo1 and S. Wimberger3

1  Dipartimento di Energetica "S. Stecco" and CSDC, Università di Firenze and INFN - Via S. Marta 3, 50139 Firenze, Italy
2  Department of Exact and Natural Sciences, Tbilisi State University - 0128 Tbilisi, Georgia
3  CNR-INFM and Dipartimento di Fisica "E. Fermi", Università degli Studi di Pisa - Largo Pontecorvo 3, 56127 Pisa, Italy


received 28 September 2006; accepted in final form 19 December 2006; published February 2007
published online 6 February 2007

Abstract
Collective quantum tunneling of a Bose-Einstein condensate between two parts of an optical lattice separated by an energy barrier is theoretically investigated. We show that by a pulsewise change of the barrier height, it is possible to switch between a tunneling regime and a self-trapped one. This property of the system is explained by effectively reducing the nonlinear dynamics of the system to that of a particle moving in a double square well potential. The analysis is performed for both attractive and repulsive interatomic forces, and emphasizes the experimental relevance of our findings.

PACS
03.75.Lm - Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations .
74.50.+r - Tunneling phenomena; point contacts, weak links, Josephson effects .
75.45.+j - Macroscopic quantum phenomena in magnetic systems .

© Europhysics Letters Association 2007