| 基于相对论平均场有效对力的中子物质BCS-BEC渡越 |
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| 引用本文： | 孙保元,郭安良,钱庄. 基于相对论平均场有效对力的中子物质BCS-BEC渡越[J]. 原子核物理评论, 2018, 35(4): 505-510. DOI: 10.11804/NuclPhysRev.35.04.505 |
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| 作者姓名： | 孙保元 郭安良 钱庄 |
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| 作者单位： | 1.兰州大学核科学与技术学院, 兰州 730000; |
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| 基金项目： | 国家自然科学基金资助项目（11875152） |
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| 摘 要： | 基于核物质的相对论Hartree-Bogoliubov（RHB）理论，采用相对论平均场单玻色子交换形式的有效对相互作用，研究了不同对力强度下双中子关联及其中的BCS-BEC渡越现象。通过引入有效衰减因子χ调节对力强度，定量分析费米面处中子对能隙和单粒子动能比值△Fn/eFn及无量纲参数1/（kFna）随费米动量kFn的演化行为，发现双中子对在χ=0.51时进入BCS-BEC渡越区域，在χ=0.67时可达到幺正极限。进而分析了中子对能隙、中子对波函数及相干长度等物理量在相应临界点处的特征，并给出渡越时双中子短程关联概率的定量判据。发现当配对中子处于平均中子间距以内的概率P（dn）?0.80时，双中子对从纯BCS耦合过渡到BCS-BEC渡越区域。Based on the relativistic Hartree-Bogoliubov theory in nuclear matter, the dineutron correlations and the crossover from Bardeen-Cooper-Schrieffer (BCS) region of neutron Cooper pairs to Bose-Einstein condensation (BEC) are investigated with the one-boson-exchange type of pairing force generated from the relativistic mean field (RMF) model. By introducing an effective factor χ in the RMF effective pairing interaction, the density dependence of the ratios between neutron pairing gap at Fermi surface and neutron Fermi kinetic energy △Fn/eFn and the dimensionless parameter 1/(kFna) are analyzed quantitatively. Then the criteria where dineutron correlations exactly reach the threshold of BCS-BEC crossover or unitary limit are determined to be χ=0.51 or 0.67, respectively. In addition, features of neutron pairing gap, Cooper pair wave function and dineutron coherence length are illustrated, and the value of the probability for partner neutrons correlated within the average inter-neutron distance, namely P (dn) ?0.80, is obtained as a criterion of BCS-BEC crossover.
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| 关 键 词： | 对关联 BCS-BEC渡越 核物质 有效对力 相对论平均场 |
| 收稿时间： | 2018-09-29 |
BCS-BEC Crossover in Neutron Matter with RMF Effective Pairing Interaction |
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| SUN Baoyuan,GUO Anliang,QIAN Zhuang. BCS-BEC Crossover in Neutron Matter with RMF Effective Pairing Interaction[J]. Nuclear Physics Review, 2018, 35(4): 505-510. DOI: 10.11804/NuclPhysRev.35.04.505 |
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| Authors: | SUN Baoyuan GUO Anliang QIAN Zhuang |
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| Affiliation: | 1.School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China;2.Engineering Research Center for Neutron Application Technology, Ministry of Education, Lanzhou University, Lanzhou 730000, China |
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| Abstract: | Based on the relativistic Hartree-Bogoliubov theory in nuclear matter, the dineutron correlations and the crossover from Bardeen-Cooper-Schrieffer (BCS) region of neutron Cooper pairs to Bose-Einstein condensation (BEC) are investigated with the one-boson-exchange type of pairing force generated from the relativistic mean field (RMF) model. By introducing an effective factor χ in the RMF effective pairing interaction, the density dependence of the ratios between neutron pairing gap at Fermi surface and neutron Fermi kinetic energy △Fn/eFn and the dimensionless parameter 1/(kFna) are analyzed quantitatively. Then the criteria where dineutron correlations exactly reach the threshold of BCS-BEC crossover or unitary limit are determined to be χ=0.51 or 0.67, respectively. In addition, features of neutron pairing gap, Cooper pair wave function and dineutron coherence length are illustrated, and the value of the probability for partner neutrons correlated within the average inter-neutron distance, namely P (dn) ?0.80, is obtained as a criterion of BCS-BEC crossover. |
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| Keywords: | Pairing correlation BCS-BEC crossover nuclear matter effetive pairing force RMF |
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