Comparison of classical chaos with quantum chaos
  We investigate chaotic behavior in a 2-D Hamiltonian system - oscillators with anharmonic coupling. We compare the classical system with quantum system. Via the quantum action, we construct Poincar\'e sections and compute Lyapunov exponents for the quantum system. We find that the quantum system is globally less chaotic than the classical system. We also observe with increasing energy the distribution of Lyapunov exponts approaching a Gaussian with a strong correlation between its mean value and energy. 
L.A. Caron, D. Huard, H. Kr\"oger, G. Melkonyan, K.J.M. Moriarty and   L.P. Nadeau