发表机构
College of Physics, Guizhou University（贵州大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过磁性GMGHS黑洞实例，证明全局拓扑数W不足以完全刻画黑洞热力学拓扑，需结合逆霍金温度在视界边界处的渐近行为来区分具有相同W的拓扑子类。
AI 中文摘要
热力学拓扑为黑洞态及其在热力学参数空间中的分支结构提供了一种拓扑分类。我们研究了四维渐近平坦的爱因斯坦-麦克斯韦-膨胀子引力中带电非极值磁性Gibbons--Maeda族的拓扑性质，特别关注其在膨胀子耦合$a=1$处的弦理论成员，即Gibbons--Maeda--Garfinkle--Horowitz--Strominger（GMGHS）黑洞。对正则外视界完整定义域上的解析分类表明，膨胀子耦合将该族划分为逆霍金温度的三种极限结构。在$a=1$处，GMGHS缺陷曲线趋近于非零的下逆温度端点，并包含单一不稳定分支。特别地，磁性GMGHS黑洞在渐近平坦的爱因斯坦-麦克斯韦-膨胀子解中明确实现了先前提出的$\overline W^{1-}$热力学拓扑子类。这一结果表明，全局拓扑数$W$本身并不能完全刻画黑洞热力学拓扑。物理视界定义域边界附近逆霍金温度的渐近行为提供了区分具有相同$W$的热力学拓扑子类的额外判据。
英文摘要
Thermodynamic topology provides a topological classification of black hole states and their branch structures in thermodynamic parameter space. We investigate the thermodynamic topology of the charged nonextremal magnetic Gibbons--Maeda family in four-dimensional asymptotically flat Einstein--Maxwell--dilaton gravity, with particular emphasis on its string-theory member at the dilaton coupling $a=1$, the Gibbons--Maeda--Garfinkle--Horowitz--Strominger (GMGHS) black hole. An analytic classification over the complete domain of regular outer horizons shows that the dilaton coupling separates the family into three limiting structures of the inverse Hawking temperature. At $a=1$, the GMGHS defect curve approaches a nonzero lower inverse temperature endpoint and contains a single unstable branch. In particular, the magnetic GMGHS black hole provides an explicit realization of the previously proposed $\overline W^{1-}$ thermodynamic topological subclass within an asymptotically flat Einstein--Maxwell--dilaton solution. This result demonstrates that the global topological number $W$ alone does not completely characterize black hole thermodynamic topology. The asymptotic behavior of the inverse Hawking temperature near the boundaries of the physical horizon domain provides an additional criterion for distinguishing thermodynamic topological subclasses with the same $W$.
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