Mobility and stochastic resonance in spatially inhomogeneous systems

The mobility of an overdamped particle, in a periodic potential tilted by a constant external field and moving in a medium with periodic friction coef ficient is examined. When the potential and the friction coefficient have t he same periodicity but have a phase difference, the mobility shows many in teresting features as a function of the applied force, the temperature, etc . The mobility shows stochastic resonance even for constant applied force, an issue of much recent interest. The mobility also exhibits a resonancelik e phenomenon as a function of the field strength and noise induced slowing down of the particle in an appropriate parameter regime. [S1063-651X(99)037 12-5].