Driven collective quantum tunneling of ultracold atoms in engineered optical lattices

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: 19 December 2006

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.