# Phase transitions in dense matter

## TL;DR

This paper discusses the nature of phase transitions in dense matter, focusing on the differences between congruent and non-congruent transitions, especially the quark deconfinement transition relevant for astrophysical phenomena.

## Contribution

It provides an analysis of non-congruent phase transitions in dense matter, emphasizing the characteristics of the quark deconfinement transition at high densities and temperatures.

## Key findings

- Non-congruent phase transitions exhibit distinct features from congruent ones.
- Quark deconfinement transition can be a non-congruent first-order transition.
- Relevance of these transitions to astrophysical events like neutron stars and supernovae.

## Abstract

As the density of matter increases, atomic nuclei disintegrate into nucleons and, eventually, the nucleons themselves disintegrate into quarks. The phase transitions (PT's) between these phases can vary from steep first order to smooth crossovers, depending on certain conditions. First-order PT's with more than one globally conserved charge, so-called non-congruent PT's, have characteristic differences compared to congruent PT's. In this conference proceeding we discuss the non-congruence of the quark deconfinement PT at high densities and/or temperatures relevant for heavy-ion collisions, neutron stars, proto-neutron stars, supernova explosions, and compact-star mergers.