Frequency response of the decoherence in a Duffing oscillator and the dispersion of the Wigner function in the Fourier domain

- Entropy growth depends on the Wigner function's dispersion in the Fourier space.
- Driving force can affect the dispersion of the Wigner function in the Fourier space.
- Peak is found in the frequency response of the entropy growth of a Duffing system.

The decoherence measured by the linear entropy is shown to be closely related to the dispersion of the Wigner function in the Fourier domain. The latter corresponds to the oscillations of the Wigner function in the phase space and can be influenced by the external driving force in driven nonlinear systems, e.g., in a Duffing-type oscillator. In the further investigations on the Duffing-type oscillator, the growth of the entropy of the system is found to be significantly dependent on the frequency of the driving force. Pronounced response peak occurs in the driving frequency response curve of the entropy of the system. Furthermore, there is good correspondence between the frequency response curve of the entropy and that of the dispersion of the Wigner function in the Fourier domain.