Atomic Nucleus as Chaotic Quantum Many-Body System

Quantum many-body chaos is described as a practical (theoretical, experimental, and computational) instru-ment in physics of mesoscopic systems of interacting particles. Using mainly nuclear physics applications, it is shown that interactions of constituents create stationary states of high complexity with respect to the nean-field basis with observable properties smoothly changing along the spectrum. Both local Gaussian orthogonal ensemble type features and the global evolution along the spectrum are used to understand the many-body physics and define thermodynamic properties of isolated mesoscopic objects. Among the examples discussed, especially interesting is a chaotic enhancement of weak perturbations illustrated by a large parity violation in neutron resonances on heavy nuclei. Artificially introduced chaotic elements are used to explore the nuclear landscape and predict phase transformations