Eur. Phys. J. B 31, 457-461 (2003)
https://doi.org/10.1140/epjb/e2003-00055-1

Macroscopic oscillations between two weakly coupled Bose-Einstein condensates

¹ Istituto Nazionale di Fisica della Materia, Italy
² International School for Advanced Studies (SISSA), via Beirut 2/4, 34014 Trieste, Italy
³ European Laboratory for Non-Linear Spectroscopy (LENS), Largo E. Fermi 2, 50125 Firenze, Italy

Corresponding author: ^a smerzi@sissa.it

Received: 2 May 2002
Revised: 19 November 2002
Published online: 6 March 2003

Abstract

We demonstrate, both from a theoretical and an experimental point of view, the possibility of realizing a weak coupling between two Bose-Einstein condensates trapped in different Zeeman states. The weak coupling drives macroscopic quantum oscillations between the condensate populations and the observed current-phase dynamics is described by generalized Josephson equations. In order to highlight the superfluid nature of the oscillations, we investigate the response of a ⁸⁷Rb non-condensate (thermal) gas in the same conditions, showing that the thermal oscillations damp more quickly than those of the condensate.