  By means of a temporal-periodic modulation of the s-wave scattering length, a
procedure to control the evolution of an initial atomic coherent state
associated with a Bosonic Josephson junction is presented. The scheme developed
has a remarkable advantage of avoiding the quantum collapse of the state due to
phase and number diffusion. This kind of control could prove useful for atom
interferometry using BECs, where the interactions limit the evolution time
stage within the interferometer, and where the modulation can be induced via
magnetic Feshbach resonances as recently experimentally demonstrated.
