Influence of Correlated Coloured Noises on an Underdamped Josephson Junction

The paper describes a non-trivial effect of realization of the electrical transport in a stochastic model of Josephson junction due to correlated colored noises. It is shown that the cross-correlation plays an important role: by controlling the correlation between the thermal and external noises, a reversal for the net voltage can be induced. It is shown that the behavior of the dc voltage versus the dc current can be manipulated by controlling the noise intensities and strength of cross-correlation. At zero dc current the strength of cross-correlations plays a role of control parameter; an increase in this parameter leads to voltage growth. Frequency content of noises is a critical parameter at small noise intensity: a reversal for the voltage can be realized by controlling the auto- and cross-correlation times of thermal and external noises. It is found that correlated noises promote the occurrence of negative conductance at small positive values of dc bias. At the same time the voltage does not assume the opposite sign of the dc bias at negative values of one due to cross-correlation between noises. It is shown that an increase in noise strength at a small friction coefficient leads to regimes which correspond to a normal, Ohmic-like transport behavior. The dependence of the voltage versus the amplitude of the ac current at small positive dc bias depicts a quasiperiodic series of windows of noise-induced anomalous regimes: negative conductance appears and disappears as the ac-amplitude strength increases.