Effective Field Theory of Emergent Symmetry Breaking in Deformed Atomic Nuclei

TL;DR

This paper develops an effective field theory framework for understanding emergent symmetry breaking in deformed atomic nuclei, incorporating additional degrees of freedom beyond Nambu-Goldstone modes to describe low-lying vibrational and rotational states.

Contribution

It extends effective field theory methods to finite, non-relativistic quantum systems like deformed nuclei, introducing new degrees of freedom for emergent symmetry breaking.

Findings

Constructed low-lying states using symmetry arguments.

Described vibrational modes as band heads of rotational bands.

Provided a general approach applicable to finite quantum systems.

Abstract

Spontaneous symmetry breaking in non-relativistic quantum systems has previously been addressed in the framework of effective field theory. Low-lying excitations are constructed from Nambu-Goldstone modes using symmetry arguments only. We extend that approach to finite systems. The approach is very general. To be specific, however, we consider atomic nuclei with intrinsically deformed ground states. The emergent symmetry breaking in such systems requires the introduction of additional degrees of freedom on top of the Nambu-Goldstone modes. Symmetry arguments suffice to construct the low-lying states of the system. In deformed nuclei these are vibrational modes each of which serves as band head of a rotational band.