# Inhomogeneity growth in two-component fermionic systems

## TL;DR

This paper investigates the growth of inhomogeneities in two-component fermionic systems using a stochastic Boltzmann-Langevin approach, revealing insights into fluctuation dynamics, cluster formation, and the influence of effective interactions.

## Contribution

The study introduces the BLOB model as an improved stochastic approach for analyzing fermionic many-body dynamics, especially in unstable and open systems like heavy ion collisions.

## Key findings

- BLOB model accurately predicts fluctuation amplitudes in nuclear matter.
- Clusterization occurs in unstable systems, matching analytical predictions.
- BLOB outperforms simplified models in simulating fermionic system dynamics.

## Abstract

The dynamics of fermionic many-body systems is investigated in the framework of Boltzmann-Langevin (BL) stochastic one-body approaches. Within the recently introduced BLOB model, we examine the interplay between mean-field effects and two-body correlations, of stochastic nature, for nuclear matter at moderate temperature and in several density conditions, corresponding to stable or mechanically unstable situations. Numerical results are compared to analytic expectations for the fluctuation amplitude of isoscalar and isovector densities, probing the link to the properties of the employed effective interaction, namely symmetry energy (for isovector modes) and incompressibility (for isoscalar modes). For unstable systems, clusterization is observed. The associated features are compared to analytical results for the typical length and time scales characterizing the growth of unstable modes in nuclear matter and for the isotopic variance of the emerging fragments. We show that the BLOB model is generally better suited than simplified approaches previously introduced to solve the BL equation, and it is therefore more advantageous in applications to open systems, like heavy ion collisions.