CRITICAL-BEHAVIOR OF A ONE-DIMENSIONAL FRUSTRATED QUANTUM XY MODEL

[摘要] A one-dimensional quantum version of the frustrated XY model is introduced which can be physically realized as a ladder of Josephson junctions at half of a flux quantum per plaquette. From a fluctuation effective action, the zero-temperature (superconductor-insulator) transition is predicted to be in the universality class of the two-dimensional classical XY-Ising model. A Monte Carlo transfer matrix is used to calculate critical exponents and central charge. A finite-size-scaling analysis of extensive calculations on small system sizes supports the prediction. The same critical behavior has recently been found for the two-dimensional classical version. Together, the results strongly support an XY-Ising-like critical behavior for these systems.

[关键词] JOSEPHSON-JUNCTION LADDERS;PHASE-TRANSITIONS;INSULATOR TRANSITION;MAGNETIC-FIELD;FLUCTUATIONS;ARRAYS