SUBODH R SHENOY

Abdus Salam International Centre for Theoretical Physics, P.O. Box 586, Trieste 34100, Italy

Abstract.

We obtain the dynamics in number and phase difference, for Bose condensates that tunnel between two wells of a double-well atomic trap, using the (nonlinear) Gross--Pitaevskii equation. The dynamical equations are of the canonical form for the two conjugate variables, and the Hamiltonian corresponds to that of a momentum-shortened pendulum, supporting a richer set of tunneling oscillation modes than for a superconductor Josephson junction, that has a fixed-length pendulum as a mechanical model. Novel modes include 'inverted pendulum' oscillations with an average angle of p; and oscillations about a self-maintained population imbalance that we term `macroscopic quantum self-trapping'. Other systems with this phase-number nonlinear dynamics include two-component (interconverting) condensates in a single harmonic trap, and He³B superfluids in two containers connected by micropores.

Keywords:  Tunneling; Bose--Einstein condensates; trapped atoms; pendulum.

Pacs Nos.  03.75.Fi; 74.50.+r; 05.30.Jp; 32.80.Pj