Thermally activated barrier crossing and stochastic resonance of a flexible polymer chain in a piecewise linear bistable potential.

We study the stochastic resonance of a flexible polymer chain crossing over a piecewise linear bistable potential. The dependence of signal to noise ratio SNR on noise intensity D , coupling constant k , and polymer length N is studied via two-state approximation. We find that the response of signal to the background noise strength is significant at optimum values of D{opt} , k{opt} , and N{opt} which suggests a means of manipulating proteins or vesicles. Furthermore, the thermally activated barrier crossing rate r{k} for the flexible polymer chain is studied. We find that the crossing rate r{k} exhibits an optimal value at an optimal coupling constant k{opt} ; k{opt} decreases with N . As the chain length N increases, the escape rate for the center of mass r{k} monotonously decreases. On the other hand, the crossing rate for the portion of polymer segment r{s} increases and saturates to a constant rate as N steps up.