Correlations in hot asymmetric nuclear matter

Abstract

The single-particle spectral functions in asymmetric nuclear matter are computed using the ladder approximation within the theory of finite temperature Green's functions. The internal energy and the momentum distributions of protons and neutrons are studied as a function of the density and the asymmetry of the system. The proton states are more strongly depleted when the asymmetry increases whereas the occupation of the neutron states is enhanced compared to the symmetric case. The self-consistent Green's function approach leads to slightly smaller energies compared to the Brueckner-Hartree-Fock approach. This effect increases with density and thereby modifies the saturation density and leads to smaller symmetry energies.

High-momentum components in the nuclear symmetry energy

“…Our microscopic many-body calculations indicate that the dependence of short-range and tensor correlations on the isospin asymmetry of the system, α = (N − Z)/(N + Z), is well understood from general theoretical principles [8]. One-body occupations, for instance, follow a systematic trend: neutrons become less depleted as the system becomes more neutron-rich, while the proton depletion increases [8,9].…”

“…Our microscopic many-body calculations indicate that the dependence of short-range and tensor correlations on the isospin asymmetry of the system, α = (N − Z)/(N + Z), is well understood from general theoretical principles [8]. One-body occupations, for instance, follow a systematic trend: neutrons become less depleted as the system becomes more neutron-rich, while the proton depletion increases [8,9].Here, rather than looking at microscopic properties, we want to quantify the effect that NN correlations have on the bulk properties of isospin asymmetric systems. By analysing the energy of symmetric, asymmetric and neutron matter obtained within a realistic many-body approach, we will draw conclusions on the impact of correlations on asymmetric systems.…”

“…The ladder approximation, implemented within the self-consistent Green's functions (SCGF) approach, provides a microscopic description of these effects via a fully dressed propagation of nucleons in nuclear matter [4]. This is achieved by (a) computing the scattering of particles via a T -matrix (or effective interaction) in the medium, (b) extracting a self-energy out of the effective interaction and (c) using Dyson's equation to build two-body propagators which are subsequently inserted in the scattering equation [8,11]. To solve the close set of equations, an iterative numerical procedure is a must.…”

“…Fully self-consistent ladder calculations in isospin asymmetric nuclear matter are scarce [8,9]. Previous results have mostly highlighted the different role of correlation in either symmetric or pure neutron matter [11].…”

“…The SCGF approach can be generalised to isospin asymmetric systems [8]. We can thus In the upper panel of Fig.…”