Equation of state of isospin asymmetric QCD with small baryon chemical potentials

TL;DR

This paper extends the equation of state of isospin asymmetric QCD to small baryon and strangeness chemical potentials using Taylor expansion coefficients, providing new insights relevant for early Universe conditions.

Contribution

It introduces a novel method to compute the equation of state at small chemical potentials using Taylor coefficients and derivatives, overcoming previous extrapolation challenges.

Findings

First results for the equation of state along the electric charge chemical potential axis.

Demonstrates the feasibility of using Taylor expansion coefficients at non-zero isospin chemical potentials.

Provides data relevant for understanding the early Universe with large lepton asymmetries.

Abstract

We extend our measurement of the equation of state of isospin asymmetric QCD to small baryon and strangeness chemical potentials, using the leading order Taylor expansion coefficients computed directly at non-zero isospin chemical potentials. Extrapolating the fully connected contributions to vanishing pion sources is particularly challenging, which we overcome by using information from isospin chemical potential derivatives evaluated numerically. Using the Taylor coefficients, we present, amongst others, first results for the equation of state along the electric charge chemical potential axis, which is potentially of relevance for the evolution of the early Universe at large lepton flavour asymmetries.