Monte Carlo study of particle renormalizations in the presence of dissipative environments

We study the Aharonov-Bohm oscillations of a charged particle on a ring of radius R coupled to a dirty metal environment. With Monte Carlo methods we evaluate the curvature of these oscillations which has the form 1/M^∗R², where M^∗ is an effective mass. We find that at low temperatures T the curvature approaches at large R>l an R independent M^∗>M, where l is the mean free path in the metal. This behavior is also consistent with perturbation theory in the particle–metal coupling parameter. At finite temperature T we identify dephasing lengths that scale as T⁻¹ at R≳l and as T^−1/4 at R⪡l.