The spectral density of the fluctuations of an underdamped, single-well, nonlinear oscillator driven by a random force has been investigated. Electronic analog experiments have demonstrated the existence of a narrow spectral peak at zero frequency; such a peak only appears, however, in those cases where the potential is non-centro-symmetric. The evolution of the peak with variation of a parameter characterizing the asymmetry of the potential, and with noise intensity, has been investigated both experimentally and theoretically. It is found that the half-width of the peak remains relatively small (of the order of the reciprocal relaxation time) over a broad range of noise intensities. The theory of the peak shape is shown to be in close agreement with experiment. The relationships of the peak to the (apparently similar) zero-frequency peaks observed previously in double-well oscillators, where they are responsible for stochastic resonance, and to the supernarrow spectral peaks found near kinetic phase transitions in periodically driven systems, are discussed.
ZERO-FREQUENCY SPECTRAL PEAKS OF UNDERDAMPED NONLINEAR OSCILLATORS WITH ASYMMETRIC POTENTIALS
MANNELLA, RICCARDO;
1991-01-01
Abstract
The spectral density of the fluctuations of an underdamped, single-well, nonlinear oscillator driven by a random force has been investigated. Electronic analog experiments have demonstrated the existence of a narrow spectral peak at zero frequency; such a peak only appears, however, in those cases where the potential is non-centro-symmetric. The evolution of the peak with variation of a parameter characterizing the asymmetry of the potential, and with noise intensity, has been investigated both experimentally and theoretically. It is found that the half-width of the peak remains relatively small (of the order of the reciprocal relaxation time) over a broad range of noise intensities. The theory of the peak shape is shown to be in close agreement with experiment. The relationships of the peak to the (apparently similar) zero-frequency peaks observed previously in double-well oscillators, where they are responsible for stochastic resonance, and to the supernarrow spectral peaks found near kinetic phase transitions in periodically driven systems, are discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
