Chaos in a time-periodically modulated honeycomb optical lattice

Rubidium atom currents in a time-periodically modulated honeycomb optical lattice are numerically computed. This modulation acts as a driving that leads to chaotic behavior in the atom dynamics. We treat this system both classically — showing the onset of chaos in lattice surface-of-section plots — and quantum mechanically — using Floquet-Bloch theory to compute the quasienergy and average energy spectrum, as well as the atomic currents induced by the modulation. The distribution of quasienergies suggest the signatures of chaos arise as the modulation amplitude increases.