SPLAY STATES IN GLOBALLY COUPLED JOSEPHSON ARRAYS - ANALYTICAL PREDICTION OF FLOQUET MULTIPLIERS

In recent numerical experiments on series arrays of overdamped Josephs on junctions, Nichols and Wiesenfeld [Phys. Rev. A 45, 8430 (1992)] di scovered that the periodic states known as splay states are neutrally stable in all but four directions in phase space. We present a theory that accounts for this enormous degree of neutral stability. The theor y also predicts the four non-neutral Floquet multipliers to within 0.1 % of their numerically computed values. The analytical approach used here may be applicable to other globally coupled systems of oscillator s, such as multimode lasers, electronic oscillator circuits, and solid -state laser arrays.