Kinetic-Theory Bounds on the Equation of State of Dense QCD Matter

TL;DR

This paper establishes new bounds on the equation of state for dense QCD matter by integrating kinetic theory constraints into existing models, narrowing the range of possible behaviors at high densities.

Contribution

It introduces a microscopic kinetic-theory constraint into model-agnostic bounds, improving the accuracy of the equation of state for dense matter.

Findings

Bounds are consistent with known low- and high-density limits.

The kinetic-theory constraint significantly reduces the range of admissible equations of state at high densities.

The method can be incorporated into future dense matter studies.

Abstract

We derive bounds on the equation of state of cold, dense matter by extending the causal, model-agnostic interpolation between chiral effective field theory and perturbative calculations with a microscopic constraint from relativistic kinetic theory. The additional condition restricts the stiffest admissible behavior of the equation of state and systematically reduces the range of allowed equations of state, with the strongest effect at high densities. The resulting bounds remain consistent with known low- and high-density limits, while the strength of the constraint depends on the density above which the kinetic-theory condition is applied. These bounds can be readily incorporated into future studies of cold, dense matter and used to assess the impact of microscopic stability conditions on equation-of-state inference.