Chern Theorem and Topological Matter in Fast-Rotating Atomic Nuclei

The Chern theorem is applied to intrinsically deformed atomic nuclei, leading to states exhibiting topological quantization of the rotation-aligned component of angular momentum averaged over Hilbert space. These topologically quantized alignment (TQA) states can emerge when collective rotation breaks intrinsic-frame time reversal symmetry, and differ fundamentally from traditional nuclear states. They exhibit formal analogies with the integer quantum Hall effect, and are a first suggestion that topological matter with novel properties might exist in nuclei. We discuss experimental signatures and speculate that TQA bulk-boundary correspondence could lead to a nuclear Chern insulator, where a rotating nucleus has an insulating bulk and unidirectional charged and uncharged currents at its surface, with detectable consequences for the energy spectrum.