A thermal-activation model for intrinsic noise in RF pumped double SQUID'S

By generalizing a technique used before by Kurkijarvi for analysis of the intrinsic-noise influence on the one-quantization loop RF-SQUID performance (a 1D problem), a thermal-activation model for a 2D case is applied for studying the same problem in the case of a two-quantization loop configuration, namely, an RF pumped double (D) SQUID. Based on this method a theoretical estimation for the flux-noise spectral densities at low frequencies is given and an optimization of the D-SQUID configuration from the noise-level and flux-coupling points of view via the parameter set values is made.