Linear response in infinite nuclear matter as a tool to reveal finite size instabilities

TL;DR

This paper demonstrates how linear response theory in infinite nuclear matter can identify and prevent finite size instabilities in nuclear effective interactions like Skyrme forces, improving their physical reliability.

Contribution

It introduces a method to predict and avoid parameter regions causing instabilities in Skyrme functionals using linear response analysis.

Findings

Linear response analysis predicts instability regions.

Certain Skyrme parameters lead to unphysical polarization.

Method helps refine effective interactions for stability.

Abstract

Nuclear effective interactions are often modelled by simple analytical expressions such as the Skyrme zero-range force. This effective interaction depends on a limited number of parameters that are usually fitted using experimental data obtained from doubly magic nuclei. It was recently shown that many Skyrme functionals lead to the appearance of instabilities, in particular when symmetries are broken, for example unphysical polarization of odd-even or rotating nuclei. In this article, we show how the formalism of the linear response in infinite nuclear matter can be used to predict and avoid the regions of parameters that are responsible for these unphysical instabilities.