Random interactions: Shedding light on nuclear structure

Regular features of nuclear spectra, including pairing, rotational, and vib rational excitations, are routinely described as resulting from the coheren t part of nucleon-nucleon interactions. However recent simulations have dem onstrated that such features arise even for a many-body system with random interactions represented by simple statistical ensembles of parameters. We study shell model type systems with random interactions and show the interp lay of various factors at work: the mean field, fermion statistics, bose-li ke statistics of fermion pairs, geometric chaoticity of randomly coupled in dividual angular momenta, and self-averaged residual interactions, all in a many-body system with chaotic dynamics.