Coherent stochastic resonance in one dimensional diffusion with one   reflecting and one absorbing boundaries
  It is shown that the single-step periodic signal (periodic telegraph signal) can not produce coherent stochastic resonance for diffusion on a segment with one absorbing and one reflecting end points while the multi-step periodic signal does. The general features of this process are exihibited. The resonant frequency is found to decrease and the mean first passage time at resonant frequency increases linearly, as we increase the length of the medium. The cycle variable is shown to be the proper argument to express the first passage time density function at resonance. A formula for first passage time density function at resonance is derived in terms of two universal functions, which clearly isolates its dependence on the length of the medium. 
Asish K. Dhara and Tapan Mukhopadhya