M. Kollmann et al., PERIODIC ORBIT ANALYSIS OF BILLIARD LEVEL DYNAMICS, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 49(1), 1994, pp. 180000001-180000004
Experimentally determined eigenvalue velocities in a Sinai billiard we
re used to establish a relation between the Pechukas-Yukawa level dyna
mics and periodic orbit theory. The first one explains easily the obse
rved Maxwellian velocity distributions, whereas the second one account
s for velocity correlations between distant levels, and a conspicuous
increase of the averaged velocities with energy.