近日，阿尔及利亚理工大学物理学院M.R. Oudih团队研究了路径积分形式下加热核中的中子-质子等矢量配对关联处理。2025年4月13日，《中国物理C》杂志发表了这一成果。

在路径积分形式下，研究组开发了一种处理有限温度下中子-质子（np）等矢量配对相关性的方法。它在相似粒子配对的情况下使用类似的方法推广了最近提出的模型。为了便于Hubbard-Stratonovich变换的使用，总哈密顿量中的配对项以方形形式表示。然后建立系统的配分函数表达式。推导了间隙方程以及系统的能量、熵和热容的表达式。

作为第一步，形式主义被数值应用于理查森模型。作为第二步，该方法使用变形Woods-Saxon平均场的单粒子能量应用于N=Z等原子核。课题组研究了间隙参数、激发能量和热容随温度的变化。结果表明，这些量的整体行为与标准FTBCS模型中的同系物相似。研究组特别注意到存在临界温度，超过临界温度配对就会消失。此外，在该方法的框架内，配对效应似乎持续超过FTBCS模型在类粒子配对情况下预测的临界温度，或在np配对情况下的推广。

附：英文原文

Title: Neutron-proton isovector pairing correlations treatment in heated nuclei within the path integral formalism

Author: M. Fellah, N.H. Allal, M.R. Oudih

Issue&Volume: 2025-04-13

Abstract: A method for the treatment of the neutron-proton (np) isovector pairing correlations at finite temperature is developed within the path integral formalism. It generalizes the recently proposed model using a similar approach in the pairing between like-particles case. The pairing terms in the total Hamiltonian are written in a square form in order to facilitate the use of the Hubbard-Stratonovitch transformation. The expression for the partition function of the system is then established. The gap equations, as well as the expressions for the energy, the entropy and the heat capacity of the system are deduced. As a first step, the formalism is numerically applied to the schematic Richardson model. As a second step, the method is applied to nuclei such as N=Z using the single-particle energies of a deformed Woods-Saxon mean-field. The variations in the gap parameters, the excitation energy and the heat capacity are studied as functions of the temperature. It is shown that the overall behavior of these quantities is similar to their homologues in the standard FTBCS model. We note in particular the existence of critical temperatures beyond which the pairing vanish. Moreover, it appears that in the framework of the present approach, the pairing effects persist beyond the critical temperatures predicted by the FTBCS model in the pairing between like-particles case or its generalization in the np pairing case.

DOI: 10.1088/1674-1137/adc4cb

Source: http://hepnp.ihep.ac.cn/article/doi/10.1088/1674-1137/adc4cb