PERSISTENT CURRENTS IN A QUANTUM RING - EFFECTS OF IMPURITIES AND INTERACTIONS

We have studied the persistent current in a quantum ring in the presence of a Gaussian impurity and/or with Coulomb interactions included. The impurity potential mixes the states, lifts the degeneracies in the energy spectrum, and reduces the persistent current from its impurity-free value. The role of interactions in the absence or presence of an impurity was found to be insignificant. We also present the results for the charge density of the system in the presence of the impurity with or without the Coulomb interactions.