  A finite one-dimensional microscopic model of a superfulid is presented. The
model consists of interacting Bose particles with an additional impurity
particle confined to a ring. Both semiclassical and exact quantum calculations
reveal dissipationless motion of impurity with increased effective mass due to
its interaction with the excitations of Bose fluid. It is shown that both the
excitation spectrum of Bose fluid and the excitation spectrum of impurity can
be analyzed using the structure of the ground state of the system.
