Parametric Number Covariance in Quantum Chaotic Spectra
  We study spectral parametric correlations in quantum chaotic systems and introduce the number covariance as a measure of such correlations. We derive analytic results for the classical random matrix ensembles using the binary correlation method and obtain compact expressions for the co- variance. We illustrate the universality of this measure by presenting the spectral analysis of the quantum kicked rotors for the time-reversal invariant and time-reversal non-invariant cases. A local version of the parametric number variance introduced earlier is also investigated. 
Vinayak, Sandeep Kumar, and Akhilesh Pandey
quant-ph math-ph math.MP