Thouless made many important contributions to the theory of many-body problems. For atomic nuclei, he cleared up the concept of 'rearrangement energy' and derived an expression for the moment of inertia of deformed nuclei.
Thouless significantly advanced our understanding of many-body problems, particularly in the context of atomic nuclei. He provided a clear definition of 'rearrangement energy' and formulated an equation for the rotational properties of deformed nuclei.