Chiral Fermi liquid approach to neutron matter

Abstract

We present a microscopic calculation of the complete quasiparticle interaction, including central as well as noncentral components, in neutron matter from high-precision two-and three-body forces derived within the framework of chiral effective field theory. The contributions from twonucleon forces are computed in many-body perturbation theory to first and second order (without any simplifying approximations). In addition we include the leading-order one-loop diagrams from the N 2 LO chiral three-nucleon force, which contribute to all Fermi liquid parameters except those associated with the center-of-mass tensor interaction. The relative-momentum dependence of the quasiparticle interaction is expanded in Legendre polynomials up to L = 2. Second-order Pauli blocking and medium polarization effects act coherently in specific channels, namely for the Landau parameters f1, h0 and g0, which results in a dramatic increase in the quasiparticle effective mass as well as a decrease in both the effective tensor force and the neutron matter spin susceptibility. For densities greater than about half nuclear matter saturation density ρ0, the contributions to the Fermi liquid parameters from the leading-order chiral three-nucleon force scale in all cases approximately linearly with the nucleon density. The largest effect of the three-nucleon force is to generate a strongly repulsive effective interaction in the isotropic spin-independent channel. We show that the leading-order chiral three-nucleon force leads to an increase in the spin susceptibility of neutron matter, but we observe no evidence for a ferromagnetic spin instability in the vicinity of the saturation density ρ0. This work sets the foundation for future studies of neutron matter response to weak and electromagnetic probes with applications to neutron star structure and evolution.a

Functional renormalization group studies of nuclear and neutron matter

“…Different approaches, such as chiral effective field theory (ChEFT [12,90,91]), chiral Fermi liquid theory [98], as well as Quantum Monte Carlo (QMC) methods using either phenomenological interactions [99,100] or ChEFT potentials [101,102,103], show satisfactory agreement in their common overlap regions of applicability at lower densities.…”

Nuclear matter response function with a central plus tensor Landau interaction

“…Other authors [18,19,13,20] have defined it without the factor k 2 12 /k 2 F . Although the physical information is the same, the Landau parameters are different in that case.…”

“…The Landau parameters have been calculated in a large variety of ways: from a G-matrix using the Reid soft-core interaction, in the formalism of the correlated basis function (CBF) using the Argonne AV18 interaction, from phenomenological interactions of Skyrme or Gogny type, or extracted from Brueckner-Hartree-Fock approach using the AV18 interaction. New calculations of Landau parameters including both central and non-central components are now available from microscopic calculations based on highprecision two-and three-body forces [13,18,19,20,21]. They can provide useful guides for the construction of phenomenological interactions of finite range, as Gogny [22] or M3Y [24], and zero range as Skyrme [25].…”

Dense nucleonic matter and the renormalization group

“…The nuclear liquid-gas phase transition has been studied extensively within the framework of chiral effective field theory (χEFT, [15] and references therein). In the left plot of Fig.…”