Parametric correlations versus fidelity decay: the symmetry breaking   case
  We derive fidelity decay and parametric energy correlations for random matrix ensembles where time--reversal invariance of the original Hamiltonian is broken by the perturbation. Like in the case of a symmetry conserving perturbation a simple relation between both quantities can be established. 
H. Kohler and T. Nagao and H.-J. St\"ockmann
quant-ph nlin.CD