Semiclassical Trace Formulas for Two Identical Particles
  Semiclassical periodic orbit theory is used in many branches of physics. However, most applications of the theory have been to systems which involve only single particle dynamics. In this work, we develop a semiclassical formalism to describe the density of states for two noninteracting particles. This includes accounting properly for the particle exchange symmetry. As concrete examples, we study two identical particles in a disk and in a cardioid. In each case, we demonstrate that the semiclassical formalism correctly reproduces the quantum densities. 
Jamal Sakhr and Niall D. Whelan