  It is demonstrated that two distant quantum wells separated by a reservoir
with a continuous spectrum can possess bound eigenstates embedded in the
continuum. These represent a linear superposition of quantum states localized
in the wells. We show that such a state can be isolated in the course of free
evolution from any initial state by a null-result measurement in the reservoir.
The latter might not be necessary in the many-body case. The resulting
superposition is regulated by ratio of couplings between the wells and the
reservoir. In particular, one can lock the system in one of the wells by
enhancing this ratio. By tuning parameters of the quantum wells, many-body
entangled states in distant wells can be produced through interactions and
statistics.
