  We present and study new mechanism of interaction between the solitons based
on the exchange interaction mediated by the localized fermion states. As
particular examples, we consider solutions of simple 1+1 dimensional scalar
field theories with self-interaction potentials, including sine-Gordon model
and the polynomial $\phi^4$, $\phi^6$ models, coupled to the Dirac fermions
with back-reaction. We discover that there is an additional fermion exchange
interaction between the solitons, it leads to the formation of static
multi-soliton bound states. Further, we argue that similar mechanisms of
formation of stable coupled multi-soliton configurations can be observed for a
wide class of physical systems.
