  We discuss the phase coherence properties of a mesoscopic normal ring coupled
to an electric environment via Coulomb interactions. This system can be mapped
onto the Caldeira-Leggett model with a flux dependent tunneling amplitude. We
show that depending on the strength of the coupling between the ring and the
environment the free energy can be obtained either by a Bethe ansatz approch
(for weak coupling) or by using a perturbative expression which we derive here
(in the case of strong coupling). We demonstrate that the zero-point
fluctuations of the environment can strongly suppress the persistent current of
the ring below its value in the absence of the environment. This is an
indication that the equilibrium fluctuations in the environment disturb the
coherence of the wave functions in the ring. Moreover the influence of quantum
fluctuations can induce symmetry breaking seen in the polarization of the ring
and in the flux induced capacitance.
