Control of unstable macroscopic oscillations in the dynamics of three coupled Bose condensates

We study the dynamical stability of the macroscopic quantum oscillations characterizing a system of three coupled Bose-Einstein condensates arranged into an open-chain geometry. The boson interaction, the hopping amplitude and the central-well relative depth are regarded as adjustable parameters. After deriving the stability diagrams of the system, we identify three mechanisms for realizing the transition from unstable to stable behaviour and analyse specific configurations that, by suitably tuning the model parameters, give rise to macroscopic effects which are expected to be accessible to experimental observation. Also, we pinpoint a system regime that realizes a Josephson-junction-like effect. In this regime, the system configuration does not depend on the model interaction parameters and the population oscillation amplitude is related to the condensate-phase difference. This fact makes estimating the latter quantity possible, since the measure of the oscillating amplitudes is experimentally accessible.