Superconductor–insulator transition in a single Josephson junction

Resistively shunted, single Josephson junctions are studied theoretically. The method complements the band picture and is aimed at the superconductor–insulator transition regime in the View the MathML source plane, where EJ and EC are the Josephson energy and the charging energy EC=e2/2C,C being the capacitance of the junction and Rq=h/4e2 and R are the quantum resistance and the shunt resistance. The I–V characteristic is formulated by a new theory and evaluated by the path-integral transfer matrix method. The obtained result is in accordance with the recent experiments.