NOISE-INDUCED SPECTRAL NARROWING IN NONLINEAR OSCILLATORS

The spectral densities of the fluctuations of noise-driven underdamped nonlinear oscillators are discussed with particular reference to the large class of systems whose eigenfrequencies vary nonmonotonically with energy. It is shown by analogue electronic experiments and theoretically that, astonishingly, the widths of their spectral peaks can sometimes decrease with increasing noise intensity