Quiet and noisy metastable voltage states in high-T-c superconductors

The interaction between the telegraph noise and background voltage fluctuat ions in the current induced dissipative state of high-T-c BiSrCaCuO thin fi lms has been investigated. Experimental time records of the voltage drop ac ross current biased thin film strips show markedly different background noi se traces in the up and down telegraph states. Detailed analysis demonstrat es that fluctuations around the telegraph voltage levels are due to a uniqu e background noise process. The apparent quiet and noisy voltage stares are due only to differences in the effective frequency bandwidth at which back ground noise is seen at distinct telegraph levels. Changes of the backgroun d noise variance ratio with changing bias current follow changes of the sta tistical average lifetimes of the random telegraph process.