标题： 核子谱函数在有限温度下和核物质中超流性的开始 显示英文标题

标题： The Nucleon Spectral Function at Finite Temperature and the Onset of Superfluidity in Nuclear Matter

摘要： 核子自能和谱函数在对称核物质的饱和密度下，于有限温度条件下进行计算。特别是讨论了这些量在高于或接近核物质超流相变临界温度时的行为。展示了热力学T-矩阵在超流临界温度（Thouless准则）处的奇异性如何反映在自能中，并相应地反映在谱函数中。对于接近费米动量的动量和接近与配对奇异性相关的临界温度，壳上自能（光学势）的实部表现出异常行为。为了比较，也计算了来自Brueckner理论K-矩阵的自能。发现在这种情况下，自能虚部中没有配对奇异性，这是由于K-矩阵中忽略了空穴-空穴散射。从自能中计算出了谱函数和有限温度下的占据数。 显示英文摘要

摘要： Nucleon selfenergies and spectral functions are calculated at the saturation density of symmetric nuclear matter at finite temperatures. In particular, the behaviour of these quantities at temperatures above and close to the critical temperature for the superfluid phase transition in nuclear matter is discussed. It is shown how the singularity in the thermodynamic T-matrix at the critical temperature for superfluidity (Thouless criterion) reflects in the selfenergy and correspondingly in the spectral function. The real part of the on-shell selfenergy (optical potential) shows an anomalous behaviour for momenta near the Fermi momentum and temperatures close to the critical temperature related to the pairing singularity in the imaginary part. For comparison the selfenergy derived from the K-matrix of Brueckner theory is also calculated. It is found, that there is no pairing singularity in the imaginary part of the selfenergy in this case, which is due to the neglect of hole-hole scattering in the K-matrix. From the selfenergy the spectral function and the occupation numbers for finite temperatures are calculated.