Quantum Phase Transitions and Particle-Hole Pair Transport in Capacitively Coupled Josephson-Junction Chains

Mahn-Soo Choi, M. Y. Choi, Sung-Ik Lee

Published 1998-02-19Version 1

We consider two chains of ultrasmall Josephson junctions, coupled capacitively with each other, and investigate the transport of particle-hole pairs and the quantum phase transitions at zero temperature. For appropriate parameter ranges, the particle-hole pairs are found to play major roles in transport phenomena; condensation of such pairs leads to the superconducting state, displaying perfect drag of supercurrents along the two chains.