2011/11/30 by S. Fiorilla, Salvatore Fiorilla, Norbert Kaiser +2
Physics and Astronomy · #Asymmetry #Chiral perturbation theory #Equation of state #Isobar #Isospin #Nuclear matter #Nuclear physics #Nuclear physics research studies #Nucleon #Particle physics #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum, superfluid, helium dynamics #Thermodynamics #nucl-th
paper · pdf · doi:10.1016/j.nuclphysa.2012.01.003
published as Nucl. Phys. A 880 (2012) 65-87 · 22 pages, 15 figures
openalex publication_date 2012/02/04 · arxiv created 2012/03/12 · arxiv updated 2012/03/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The free energy and the equation of state of isospin-asymmetric nuclear matter are calculated at finite temperature up to three loop order in the framework of in-medium chiral perturbation theory, systematically incorporating one- and two-pion exchange dynamics to this order. Effects from the two-pion exchange with explicit Δ-isobar excitation are included, as well as three-body forces. We construct the phase diagram of nuclear matter for different proton fractions xp and investigate the dependence of nuclear matter properties on the isospin-asymmetry. A detailed study of the liquid-gas phase transition is performed. For isospin-symmetric nuclear matter we find a critical temperature of 15.1 MeV; as the isospin-asymmetry is increased, the liquid-gas coexistence region decreases until it disappears at xp ≈ 0.05, while nuclear matter becomes unbound at xp ≈ 0.12. The quadratic expansion of the free energy in the asymmetry parameter δ is a good approximation at low temperature even for large δ. An estimate of chiral four-body correlations in nuclear and neutron matter is also performed and the corrections from such four-body interactions are found to be small.