FLUX NOISE NEAR THE BEREZINSKII-KOSTERLITZ-THOULESS TRANSITION

The flux noise in Josephson junction arrays is studied in the critical regime above the Berezinskii-Kosterlitz-Thouless transition. In proxi mity-coupled arrays a local Ohmic damping for the phases is relevant, giving rise to anomalous vortex diffusion and a dynamic scaling of the flux noise in the critical region. The flux noise exhibits a crossove r from white to 1/f noise at a frequency omega(xi) proportional to xi( -z) with a dynamic exponent z = 2. (C) 1998 American Institute of Phys ics. [S0021-3640(98)00816-0].