2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28105We 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.REVTeX, EPS figures. Submitted to PRLMesoscale and Nanoscale PhysicsSuperconductivitytext