非对称核质的超流性研究

Pair correlations, which embody the tendency of pairing between the microscopic particles, are an important microscopic mechanism influencing the material structures and properties. The vortex structure, neutrino emission and cooling process in neutron stars are crucially dependent on the pairing gap value of the nucleons. Accordingly, to evaluate the gap value in different partial wave channel accurately and reasonably is still an important issue in nuclear physics. In the present project, we will employ the theory of superfluidity beyond the BCS approximation and the microscopic Brueckner-Hartree-Fock many-body theory, 1) to study the effects of the angle dependence of the pairing gap and the coupling of the neutron-neutron, neutron-proton, proton-proton Cooper pairs on the superfluidity in asymmetric nuclear matter; 2) to calculate the magnitude of the pairing gap in the primary partial wave channel by considering the screening effect, the self-energy effect, the three-body force effect and the angle dependence of the pairing gap simultaneously. The results will provide more available input for the study of the rotation dynamics and thermal evolution of neutron stars. Moreover, we will try to derive the effective pairing interaction (density- and asymmetry-dependent) from the results for the relative research in finite nuclei.

对关联是影响物质结构性质的重要微观物理机制，反映了微观粒子之间的配对倾向。中子星内部的涡旋结构、中微子发射和冷却等与核子间的对关联能隙值密切相关，合理与精确地计算各分波的超流相能隙值是核物理的一个重要课题。本项目拟将采用推广的BCS理论结合微观多体Brueckner-Hartree-Fock理论方法，研究非对称核物质中能隙的方向依赖性及中子-中子、中子-质子、质子-质子Cooper对间的耦合对超流相性质的影响。并同时考虑屏蔽效应、自能效应、三体核力效应和能隙的方向依赖性，计算主要分波的超流相能隙值，为研究中子星的转动动力学及热力学演化提供可靠的输入量。在此基础上，尝试提取有效的对相互作用(密度与非对称度依赖的)，以用于有限核的相关研究中。

对关联作为近独立粒子近似的重要补充，反应了微观粒子间的配对倾向，在凝聚态物理、核物理、粒子物理有广泛的研究。中子星冷却、晕核的结构以及Gamow-Teller激发态结构都与核子间的能隙密切相关, 合理与精确地计算各超流相能隙值是核物理的一个重要课题。由于核子间的配对是处于核介质中的准粒子间的配对，介质对于能隙的影响极其重要。精确的能隙计算要求准确的介质的信息，其中较为重要的一个影响因素是核子的自能。基于此，我们改进了计算核子自能的微观多体BHF方法，得到了较为可靠的核子的自能信息，进而计算了核物质中的n-p及n-n超流相能隙，并从中提取了有效的n-p对相互作用。此外我们还计算了介质中核子的有效质量、谱函数等其他信息，为中子星结构的研究以及重离子反应提供较为微观可靠的输入量。