INTERAVALANCHE CORRELATIONS IN THE SELF-ORGANIZED CRITICAL-STATE OF AMULTIJUNCTION SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE

A discrete-time model of a two-dimensional lattice of Josephson juncti ons [multijunction superconducting quantum interference device (SQUID) ] equivalent to the Abelian sandpile model with currents as heights wa s studied by computer simulation. We use various methods of injection of current into the lattice: similar to the real experimental conditio ns and used previously in sandpile simulations, deterministic and stoc hastic. For most of these methods the probability density of voltage ( an equivalent of avalanche size distribution) demonstrates a universal power-law behavior commonly accepted as the only indicator of self-or ganized criticality. We found that the characteristics specific for ea ch method of injection are interavalanche correlators. They show quasi periodic behavior (similar to the bulk-SQUID effect observed in real e xperiments) for deterministic injection, and ordinary exponential deca y for strongly stochastic injection. [S1063-651X(98)05502-0].