  We offer an alternative to the conventional network formulation of quantum
computing. We advance the analog approach to quantum logic gate/circuit
construction. As an illustration, we consider the spatially extended NOT gate
as the first step in the development of this approach. We derive an explicit
form of the interaction Hamiltonian corresponding to this gate and analyze its
properties. We also discuss general extensions to the case of certain
time-dependent interactions which may be useful for practical realization of
quantum logic gates.
