  We introduce a model that explains the phenomenon of correlation-assisted
tunneling and puts it in a broader context. This model assumes the existence of
an effective force of pure quantum nature between nearby fragments of
correlated matter that results due to interference effects. The magnitude of
this force depends on the amount of coherence between different locations; it
attains a maximum value for fragments in a perfect superfluid state and
disappears entirely when the fragments are in the Mott Insulator state. The
force can also be explained in terms of the Bohmian quantum potential. We
illustrate the implications of this force on the transport of cold atoms
through simple potential structures, the triple-well harmonic trap and optical
lattices.
