Effect of Boundary Conditions on Fluctuations Measures

A change in boundary conditions (BC) from uniform Dirichlet to non-identical BC on the edges of a triangular billiard often brings about a dramatic change in quantum spectral fluctuations. We provide a theory for this based on periodic orbits and show that non-identical BC on adjacent edges can lead to a quantum splitting of periodic orbit families which results in a significant change in the form factor. Thus, the classical spectrum alone cannot determine quantum correlations.