Off-shell pairing correlations from meson-exchange theory of nuclear forces
Off-shell pairing correlations from meson-exchange theory of nuclear forces
复制标题
核力介子交换理论的离壳配对相关性
DOI：
10.1103/physrevc.68.065805
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发表时间：
2003
影响因子：
3.1
通讯作者：
A. Sedrakian
中科院分区：
文献类型：
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作者：
A. Sedrakian
本文基于核相互作用的介子交换图，建立了核系统中的离质量壳层配对关联模型。模型中的时间延迟由福克交换图产生。重子复能隙方程的核与介子在介质中的谱函数有关，在无规相位近似下，该谱函数是非微扰的。该模型适用于低密度中子物质在中子星星壳分离的相互作用为一个远程的一π交换组件和一个短程组件参数化的朗道费米液体参数。由此产生的Eliashberg型耦合非线性积分方程求解的迭代过程。我们发现，自能扩展到几十兆电子伏的顺序的离壳能量。在低能量下，由于耦合到π介子模式而导致的中子对相关性的阻尼很小，但随着能量的增加而变得越来越重要。我们讨论了一种改进的拟经典近似，并在此近似下得到了数值解。
We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The kernel of the complex gap equation for baryons is related to the in-medium spectral function of mesons, which is evaluated nonperturbatively in the random phase approximation. The model is applied to the low-density neutron matter in neutron star crusts by separating the interaction into a long-range one-pion-exchange component and a short-range component parametrized in terms of Landau Fermi liquid parameters. The resulting Eliashberg-type coupled nonlinear integral equations are solved by an iterative procedure. We find that the self-energies extend to off-shell energies of the order of several tens of MeV. At low energies the damping of the neutron pair correlations due to the coupling to the pionic modes is small, but becomes increasingly important as the energy is increased. We discuss an improved quasiclassical approximation under which the numerical solutions are obtained.