Monte Carlo studies of charging effects in ultra-small tunnel junctions.

摘要

This thesis contains studies of the transport properties of tunneling systems with strong charging and Coulomb blockade effects.; In the first part of the thesis, the transport properties of the dissipative tunnel junction are calculated by a canonical Monte Carlo evaluation of the path integral of the junction. We are able to identify a quantum phase transition from a disordered, insulating phase to an ordered, conducting phase when many-body, final-state effects dominate the physics. In the second part, the consequences of minimally coupling the junction to the external environment are explored. We map the path integral to a grand canonical partition function and simulate the physics of a one dimensional Coulomb gas. We obtain the phase diagram for the dissipative tunnel junction with a charge offset. The phase diagram indicates that the charge offset is capable of driving the system into the ordered phase when the charge offset is one-half the electron charge.