Nuclear deformation in the configuration-interaction shell model

TL;DR

This paper presents a Monte Carlo method within the configuration-interaction shell model to analyze nuclear shape distributions at finite temperature, focusing on quadrupole deformation and shape transitions in samarium isotopes.

Contribution

It introduces a novel auxiliary-field Monte Carlo approach to compute finite-temperature quadrupole distributions and shape probabilities in the shell model framework.

Findings

Successfully applied to samarium isotopes showing shape crossover

Provides detailed probability distributions of nuclear deformation

Enhances understanding of nuclear shape phase transitions

Abstract

We review a method that we recently introduced to calculate the finite-temperature distribution of the axial quadrupole operator in the laboratory frame using the auxiliary-field Monte Carlo technique in the framework of the configuration-interaction shell model. We also discuss recent work to determine the probability distribution of the quadrupole shape tensor as a function of intrinsic deformation $\beta,\gamma$ by expanding its logarithm in quadrupole invariants. We demonstrate our method for an isotope chain of samarium nuclei whose ground states describe a crossover from spherical to deformed shapes.