Correlations within eigenvectors and transition amplitudes in the two-body random interaction model

It is shown that the two-body character of the interaction in a many-body system gives rise to specific correlations between the components of compound states, even if this interaction is completely random. Surprisingly, these correlations increase with the increase of the number of active (valence) particles. Statistical theory of transition amplitudes between compound states, which takes into account these correlations is developed and tested within the framework of the two-body random interaction model. It is demonstrated that a feature, which can be called ‘‘correlation resonance,’’ appears in the distribution of the transition matrix amplitudes, since the correlations strongly reduce the transition amplitudes at the tails and increase them near the maximum of the distribution.