I just read a bit of , by Stephano Nonnenmacher. 

I am still surprised when I find these articles by the quantum chaos community who outright ignore (ok, let's be polite, just don't know about) the dynamical approaches to quantum chaos such as the Loschmidt echo. They fill every introduction with things like "one is led from a dynamical to a time-independent problem", and "the associated quantum system has linear dynamics". Just bollocks. The classical Liouville dynamics in phase space is also linear !!! Give it up already, the Bohigas conjecture sure was interesting but there are more interesting things to look at now...