The mean first-passage time for an asymmetric bistable system driven by two colored noises

By means of an extended colored-noise approximation, we investigated the effects of asymmetry of the potential and noises on the mean first-passage time T+ (x(s1) -> x(s2)) and T_ (x(s2) -> x(s1)) in two opposite directions in an asymmetric bistable system (here x(s1) and x(s2) are stable points of the asymmetric bistable system). Numerical results show that T+ (x(s1)-> x(s2)) decreases with increasing of tau(1) (the correlation time of multiplicative noise) and tau(2) (the correlation time of additive noise) T_ (x(s2)-> x(s1)) increases with increasing of tau(1) and tau(2). The curves of T+ (x(s1)-> x(s2)) versus A and T_ (x(s2)-> x(s1)) versus lambda are single-peaked. T+ (x(s1)-> x(s2)) will increase when r increases, but T_ (x(s2)-> x(s1)) will decrease when r increases.