Generalized Bose–Einstein Condensation in Superconductivity

M.Á. De la Casa, J. Getino, MANUEL DE LLANO +1 more

Sadhan K. Adhikari, M. Casas, Antonio Puente +6 more

M. Grether, Mauricio Fortes, FJ Sevilla +5 more

Augusto Smerzi, S. Raghavan

Summary form only given. The recent experimental observation of Bose-Einstein condensation (BEC) of trapped, dilute gas of alkali atoms, and their manipulation have opened a new chapter in the physics of systems involving the interplay of macroscopics and quantum coherence. Here, we study the 'secondary' quantum effects, i.e., the quantum corrections to the semi-classical Gross-Pitaevskii equation, for two weakly-linked Bose-Einstein condensates. We hence generalize the Josephson current-phase relations by including the effects of quantum fluctuations of the pertinent observables. Such equations will also describe the quantum fluctuations in the Josephson dynamics between two weakly linked mesoscopic superconducting grains.

MANUEL DE LLANO

Cédric Roux, Andreas Emmert, Adrian Lupaşcu +5 more

We have produced a Bose-Einstein condensate (BEC) on an atom chip using only superconducting wires in a cryogenic environment. We observe the onset of condensation for 1·10 4 atoms at a temperature of 100 nK. This result opens the way for studies of atom losses and decoherence in a BEC interacting with a superconducting surface. Studies of dipole-blockade with long-lived Rydberg atoms in a small and dense atomic sample are underway.