Bulk Properties of Nuclear Systems and 3-Nucleon Forces

理论核结构物理学的一个基本目标是试图根据真实的核子-核子相互作用来描述核系统的基本性质（核物质的能量和饱和密度以及有限核的能量和半径），拟合以再现NN散射数据。这一目标只有在考虑到狄拉克-布鲁克纳-哈特里-福克方法的相对论效应（允许核子狄拉克旋量的介质依赖性），或者在核相互作用的现代手征场论描述中允许3-核子力的情况下才能实现。该项目的一个目的是在无限核物质以及有限核中系统地比较这两种方法。这将允许识别有限核中表面的特定后果，这对于识别核状态方程是重要的。这个状态方程是模拟天体物理物体（超新星、中子星、引力波源）的重要组成部分。将特别注意质子和中子之间的配对关联的作用。在无限核物质中相应的BCS方程的解预言了一个大的能隙，而在有限核中没有观察到这种配对现象的信号。为了实现该项目的目标，计划开发一种新技术，用于求解核介质中的2粒子和3粒子方程，并测试一种新方法，根据对无限物质获得的结果描述有限核的性质。

A basic aim of theoretical nuclear structure physics is the attempt to describe the basic properties of nuclear systems (energy and saturation density of nuclear matter as well as energy and radius of finite nuclei) in terms of realistic nucleon-nucleon interaction, fitted to reproduce the NN scattering data. This aim can only be achieved if either relativistic effects of the Dirac-Brueckner-Hartree-Fock approach, which allow for a medium dependence of the nucleon Dirac spinors, are taken into account, or if one allows for 3-nucleon forces within modern chiral field theory description of the nuclear interaction. One aim of this project is a systematic comparison of these 2 approaches in infinte nuclear matter as well as finite nuclei. This will allow to identify the specific consequences of the surface in finite nuclei, which is important for the identification of the nuclear equation of state. This equation of state is an important ingredient of simulation of astrophysical objects (supernovae, neutron stars, sources of gravitational waves). Special attention will be paid to the role of pairing correlation between protons and neutrons. Solution of the corresponding BCS equation in infinite nuclear matter predict a large gap, while no signal of such pairing phenomena are observed in finite nuclei. To achieve the goals of this project it is planned to develop a new technique for the solution of 2- and 3-particle equations in the nuclear medium and to test a new approach, describing the properties of finite nuclei on the basis of results obtained for infinite matter.