Origin of quantum chaos for two particles interacting by short-range potentials - art. no. 026201

We address the problem of two confined one-dimensional particles of arbitra ry masses interacting by general short-range potentials. We study under wha t conditions quantum chaos emerges for the system by analyzing its spectrum statistics. We show that these conditions are directly connected with a sp ecific feature of the underlying classical dynamics, namely, the ergodicity in the changes of the particles momenta. Quantum mechanically this prevent s one from obtaining the exact wave function through the Bethe ansatz. Poss ible extensions for many-body systems are also discussed.