COTUNNELING TRANSPORT AND QUANTUM PHASE TRANSITIONS IN COUPLED JOSEPHSON-JUNCTION CHAINS WITH CHARGE FRUSTRATION

摘要: We investigate the quantum phase transitions in two capacitively coupled chains of ultra-small Josephson-junctions, with emphasis on external charge effects. The particle-hole symmetry system is broken by gate voltage applied to each superconducting island, and resulting induced introduces frustration system. Near maximal-frustration line, where transformed into a spin-1/2 Heisenberg antiferromagnetic chain, cotunneling particles along shown play major role transport drive transition out charge-density wave insulator, as Josephson-coupling energy increased. also argue briefly that slightly off universality class remains same right still being driven pairs.