在轻核中寻找散射矩阵的双极点
Search for the Double Poles of the Scattering Matrix in Light Nuclei
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中文总结 AI 辅助
该研究利用耦合通道伽莫夫壳层模型，以ℓ = 1自旋轨道强度为控制参数，在⁶Li、⁷Li、⁷Be和⁸Be中寻找散射矩阵双极点，分析其在多种物理量上的印记，发现其特征依赖通道，阈值效应影响可及性。
中文摘要 AI 辅助
例外点（EPs）是非厄米简并点，在此处两个本征值及其本征向量合并，产生一个有缺陷的哈密顿量和S矩阵的双极点。利用以ℓ = 1自旋轨道强度为控制参数的耦合通道伽莫夫壳层模型，我们在⁶Li、⁷Li、⁷Be和⁸Be中定位并表征EPs，并分析它们在能量、宽度、相位刚性、光谱因子、弹性截面、存活概率和光谱函数上的印记。发现EPs在散射和时域可观测量中的特征强烈依赖于通道，阈值效应在确定参数空间中EP的可及性方面起决定性作用。
英文摘要
Exceptional points (EPs) are non-Hermitian degeneracies at which two eigenvalues and their eigenvectors coalesce, producing a defective Hamiltonian and a double pole of the $S$-matrix. Using the coupled-channel Gamow Shell Model with the $\ell=1$ spin-orbit strengths as control parameters, we locate and characterize EPs in $^6\text{Li}$, $^7\text{Li}$, $^7\text{Be}$, and $^8\text{Be}$, and analyze their imprint on energies, widths, phase rigidity, spectroscopic factors, elastic cross sections, survival probabilities, and spectral functions. The signatures of the EP in scattering and time-domain observables are found to be strongly channel-dependent, and threshold effects play a decisive role in determining the accessibility of the EP in parameter space.
