2023/12/19 by Eemeli Annala, Tyler Gorda, J. Hirvonen +4 · 1 voice · 22 citations
Physics and Astronomy · #Gamma-ray bursts and supernovae #High-Energy Particle Collisions Research #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.1038/s41467-023-44051-y
openalex publication_date 2023/12/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Neutron-star cores contain matter at the highest densities in our Universe. This highly compressed matter may undergo a phase transition where nuclear matter melts into deconfined quark matter, liberating its constituent quarks and gluons. Quark matter exhibits an approximate conformal symmetry, predicting a specific form for its equation of state (EoS), but it is currently unknown whether the transition takes place inside at least some physical neutron stars. Here, we quantify this likelihood by combining information from astrophysical observations and theoretical calculations. Using Bayesian inference, we demonstrate that in the cores of maximally massive stars, the EoS is consistent with quark matter. We do this by establishing approximate conformal symmetry restoration with high credence at the highest densities probed and demonstrating that the number of active degrees of freedom is consistent with deconfined matter. The remaining likelihood is observed to correspond to EoSs exhibiting phase-transition-like behavior, treated as arbitrarily rapid crossovers in our framework.