2024/09/24 by Dong Bai, Bai, Dong, Zhongzhou Ren +1 · 1 citation
Chemistry · Physics and Astronomy · #Advanced NMR Techniques and Applications #Advanced Physical and Chemical Molecular Interactions #FOS: Physical sciences #Nuclear Theory (nucl-th) #Nuclear physics research studies
paper · pdf · doi:10.48550/arxiv.2409.15716
openalex publication_date 2024/09/24 · openalex created_date 2024/10/26 · openalex updated_date 2026/07/28
Bohr's compound nucleus theory is one of the most important models in nuclear physics, with far-reaching applications in nuclear science and technology. This model generally assumes that the participating nucleons attain a thermal equilibrium characterized by the microcanonical ensemble before subsequent decays. However, from a theoretical viewpoint, it remains uncertain whether this assumption is universally valid. In this Letter, we critically examine this longstanding assumption through the lens of the eigenstate thermalization hypothesis (ETH), a cornerstone of the modern quantum thermalization theory. Utilizing the time-dependent configuration interaction shell model, it is found that, in certain cases, the long-time averages of nucleon occupation numbers can exhibit significant deviations from the microcanonical ensemble averages, in contrast to the conventional expectation. We attribute this discrepancy primarily to the violation of the ETH in the presence of isospin symmetry and discover that incorporating a substantial isospin-breaking term into the shell-model Hamiltonian can effectively restore the nucleon thermalization.