Role of the DC component in producing chaos in the kicked rotor

Quantify the contribution of a static (DC) component in the time-periodic drive of the kicked rotor Hamiltonian H(t)=L^2/(2I)+K cos(θ) Σ_{n∈ℤ} δ(t−nT) to the onset and strength of classical chaotic dynamics; ascertain whether inclusion of a DC term is necessary, sufficient, or merely enhances chaos when combined with a finite number of AC frequency components.

Background

The authors highlight that the kicked rotor’s pulse train contains a DC component when expanded into harmonics, and they suggest that this DC component may be crucial for chaos. They explicitly identify the importance of the DC term as an unresolved question and note that the transition is not well understood.

They intend to paper the influence of the DC component more fully, underlining this as a targeted open problem in the comparison between integrable and chaotic driven rotor models.