Perturbative QCD and the Neutron Star Equation of State

Understand

We construct a physics-agnostic approach to the neutron star (NS) equation of state (EoS) based on a sound speed model, which connects both low-density information from nuclear theory and high-density constraints from perturbative QCD (pQCD).

• Using this approach, we study the impact of pQCD calculations on NS EoS that have been constrained by astrophysical observations.
• We find that pQCD affects the EoS mainly beyond the densities realized in NS.
• Furthermore, we observe an interesting interplay between pQCD and astrophysical constraints, with pQCD preferring softer EoS for the heaviest NS while recent NICER observations suggest the EoS to be stiffer.