  We study the coherence dynamics of a kicked two-mode Bose-Hubbard model
starting with an arbitrary coherent spin preparation. For preparations in the
chaotic regions of phase-space we find a generic behavior with Flouquet
participation numbers that scale as the entire $N$-particle Hilbert space,
leading to a rapid loss of single particle coherence. However, the chaotic
behavior is not uniform throughout the chaotic sea, and unique statistics is
found for preparations at the vicinity of hyperbolic points that are embedded
in it. This is contrasted with the low log(N) participation that is responsible
for the revivals at the vicinity of isolated hyperbolic instabilities.
