BCS-BEC crossover of neutron pairs in symmetric and asymmetric nuclear matter
BCS-BEC crossover of neutron pairs in symmetric and asymmetric nuclear matter
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DOI：
10.1103/physrevc.76.064316
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发表时间：
2007-10
影响因子：
3.1
通讯作者：
J. Margueron;H. Sagawa;K. Hagino
中科院分区：
文献类型：
--
作者：
J. Margueron;H. Sagawa;K. Hagino
我们提出了新型的密度依赖接触配对相互作用，它再现了通过基于真实核子核相互作用的微观处理获得的对称和中子物质中的配对间隙。这些相互作用能够模拟裸相互作用或由介质偏振效应屏蔽的相互作用的配对间隙。结果表明，介质偏振效应不能转化为通常的接触相互作用密度幂律函数，需要引入另一个等标量项。利用这些接触相互作用研究了对称和不对称核物质中中子对的 BCS-BEC 交叉。这项工作表明，裸配对和屏蔽配对相互作用导致对称核物质中 BCS-BEC 交叉的不同特征。对于屏蔽配对相互作用，在 k{sub Fn}{approx}0.2 fm{sup -1}（中子密度 {rho}{sub n}/{rho}{sub 0}{approx}10{sup -3}）处的对称物质中形成双中子 BEC 态。相反，裸相互作用在任何中子密度下都不会形成 BEC 态。
We propose new types of density-dependent contact pairing interactions which reproduce the pairing gaps in symmetric and neutron matters obtained by a microscopic treatment based on realistic nucleon nucleon interaction. These interactions are able to simulate the pairing gaps of either the bare interaction or the interaction screened by the medium polarization effects. It is shown that the medium polarization effects cannot be cast into the usual density power law function of the contact interaction and require the introduction of another isoscalar term. The BCS-BEC crossover of neutron pairs in symmetric and asymmetric nuclear matters is studied by using these contact interactions. This work shows that the bare and screened pairing interactions lead to different features of the BCS-BEC crossover in symmetric nuclear matter. For the screened pairing interaction, a two-neutron BEC state is formed in symmetric matter at k{sub Fn}{approx}0.2 fm{sup -1} (neutron density {rho}{sub n}/{rho}{sub 0}{approx}10{sup -3}). In contrast, the bare interaction does not form the BEC state at any neutron density.