Speakers
Description
The formation of nuclear clusters, emerging as many-body correlations at sub-saturation densities, constitutes an essential feature for the construction of a reliable Equation of State (EOS). Phenomenological models based on energy density functionals (EDFs) offer a convenient approach to account for these bound states by introducing clusters as additional degrees of freedom (DOF)[1].
In this talk, we present a generalized non-relativistic mean-field framework to include light cluster DOF [2] and investigate the thermodynamical stability of warm, dilute nuclear matter. We characterize the spinodal boundary of isospin-symmetric nuclear matter through the analysis of the curvature matrix of the free-energy density, providing also a comparison with previous results obtained within a linearized dynamical (Vlasov) approach [3].
A key point is the inclusion of in-medium effects for light clusters via a density-dependent infrared momentum cutoff, which effectively accounts for Pauli-blocking and the associated reduction of low-momentum quasiparticle states. We show that the implementation of such a cutoff requires additional rearrangement contributions to the chemical potentials and single-particle energies which significantly modify both the extension of the spinodal region and the nature of unstable modes. In particular, the stiffness of the cutoff’s density dependence drives the phase dynamics: while clusters and nucleons fluctuate in-phase when in-medium effects are neglected, a sufficiently strong density dependence can induce out-of-phase fluctuations, pushing clusters toward low-density regions as instabilities grow. A rich phenomenology further emerges from the competition and mutual coupling between the different cluster species (deuterons and $\alpha$ particles) included in our study.
Our results provide new insights into the multi-faceted nature of the nuclear EOS in the warm, dilute regime, with direct implications for the fragmentation processes in heavy-ion collisions and the physics of neutron-star crusts.
[1] S. Typel, G. Röpke, T. Klähn, D. Blaschke, and H. H. Wolter, Phys. Rev. C 81, 015803 (2010).
[2] S. Burrello, C. Piazza, R. Wang, and M. Colonna, arXiv preprint arXiv:2603.02060 (2026).
[3] R. Wang, S. Burrello, M. Colonna, and F. Matera, Phys. Rev. C 110, L031601 (2024).