  Quantum characteristics of the Topological Non-connectivity Threshold (TNT),
introduced in F.Borgonovi, G.L.Celardo, M.Maianti, E.Pedersoli, J. Stat. Phys.,
116, 516 (2004), have been analyzed in the hard quantum regime. New interesting
perspectives in term of the possibility to study the intriguing
quantum-classical transition through Macroscopic Quantum Tunneling have been
addressed.
