We are searching for and exploring complexity in quantum systems!
In classical systems, the width of a chaotic region
can be estimated from the integral of a perturbation
along the separatrix orbit.
We derive an analogous relation for a discrete quantum system
by taking the average of the perturbation in
the interaction picture and using an eigenstate state with
energy near that of the separatrix.
Quantum chaos on the separatrix of the periodically perturbed Harper
model (on arxiv)
Classical orbits on the left.
Husimi functions showing phase space of Floquet states
of the associated quantum system on the right.
