Equation of state in the pion condensation phase in the asymmetric nuclear matter using a holographic QCD model

TL;DR

This paper uses a holographic QCD model to analyze the equation of state in asymmetric nuclear matter, revealing phase transition delays and insights into chiral symmetry breaking in pion condensation phases.

Contribution

It introduces a holographic QCD approach to study asymmetric nuclear matter, showing phase transition delays and detailed behavior of pion and baryon contributions.

Findings

The symmetry energy and slope parameter match empirical values.

The phase transition to pion condensation is delayed compared to pure mesonic matter.

Pion contribution to isospin density increases with chemical potential.

Abstract

We study the asymmetric nuclear matter using a holographic QCD model by introducing a baryonic charge in the infrared boundary. We first show that, in the normal hadron phase, the predicted values of the symmetry energy and it's slope parameter are comparable with the empirical values. We find that the phase transition from the normal phase to the pion condensation phase is delayed compared with the pure mesonic matter: The critical chemical potential is larger than the pion mass which is obtained for the pure mesonic matter. We also show that, in the pion condensation phase, the pion contribution to the isospin number density increases with the chemical potential, while the baryonic contribution is almost constant. Furthermore, the value of chiral condensation implies that the enhancement of the chiral symmetry breaking occurs in the asymmetric nuclear matter as in the pure mesonic matter. We also give a discussion on how to understand the delay in terms of the 4-dimensional chiral Lagrangian including the rho and omega mesons based on the hidden local symmetry.