The random-matrix-theory approach to the avoided-crossings probability distribution for quantum chaotic systems is proposed. Analytical results are obtained for all three (orthogonal, unitary, and symplectic) universality classes of physical systems as well as for systems with partially broken time-reversal invariance. The numerical experiments on the kicked-top model give results in excellent agreement with the theoretical predictions.

• Received 17 June 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.2749