标题： 有限温度下的介质相似重整化群 显示英文标题

标题： In-Medium Similarity Renormalization Group at Finite Temperature

摘要： 有限温度下原子核的研究对于核天体物理学和核反应科学的许多领域都具有极大的兴趣。 现在已经有多种从量子色动力学相互作用出发计算原子核性质的从头算方法可用，但应用大多局限于零温情况。 在本工作中，我们将其中一种方法，即介质相似重整化群（IMSRG），扩展到了有限温度。 使用一个精确可解的示意图模型来捕捉核相互作用的基本特征，我们展示了有限温度下FT-IMSRG能够准确确定原子核的能量特性，并探索了FT-IMSRG在不同参数区域（如强配对和弱配对）的准确性。 为了迎接有限核和无限物质的FT-IMSRG应用，我们讨论了选择使用正则系综和广义正则系综所带来的差异。 在未来的工作中，我们将应用真实的核相互作用的FT-IMSRG来计算有限温度下的核结构和反应性质，这些性质是理解恒星环境中核合成或热复合核反应建模的重要组成部分。 显示英文摘要

摘要： The study of nuclei at finite temperature is of immense interest for many areas of nuclear astrophysics and nuclear-reaction science. A variety of ab initio methods are now available for computing the properties of nuclei from interactions rooted in Quantum Chromodynamics, but applications have largely been limited to zero temperature. In the present work, we extend one such method, the In-Medium Similarity Renormalization Group (IMSRG), to finite temperature. Using an exactly-solvable schematic model that captures essential features of nuclear interactions, we show that the FT-IMSRG can accurately determine the energetics of nuclei at finite temperature, and we explore the accuracy of the FT-IMSRG in different parameter regimes, e.g., strong and weak pairing. In anticipation of FT-IMSRG applications for finite nuclei and infinite matter, we discuss differences arising from the choice of working with the canonical and the grand canonical ensembles. In future work, we will apply the FT-IMSRG with realistic nuclear interactions to compute nuclear structure and reaction properties at finite temperature, which are important ingredients for understanding nucleosynthesis in stellar environments, or modeling reactions of hot compound nuclei.