  We study quantum chaos in a non-KAM system, i.e. a kicked particle in a
one-dimensional infinite square potential well. Within the perturbative regime
the classical phase space displays stochastic web structures, and the diffusion
coefficient D in the regime increases with the perturbative strength K giving a
scaling $D \propto K^{2.5}$, and in the large K regime D goes as K^2. Quantum
mechanically, we observe that the level spacing statistics of the quasi
eigenenergies changes from Poisson to Wigner distribution as the kick strength
increases. The quasi eigenstates show power-law localization in the small K
region, which become extended one at large K. Possible experimental realization
of this model is also discussed.
