In this letter we use the Carathéodory's approach to thermodynamics, to construct the thermodynamic manifold of the Hayward black hole. The Pfaffian form representing the infinitesimal heat exchange reversibly is considered to be $\delta Q_{\mathrm{rev}}\equiv \mathrm{d}{r}_s-{\mathcal{F}}_H\mathrm{d}l$, previously obtained by Molina & Villanueva [1], where $r_s$ is the Schwarzschild radius, l is the Hayward's parameter responsible for the possible regularization of the Schwarzschild black hole, and ${\mathcal{F}}_H$ is the intensive variable called the Hayward's force. By solving the associated Cauchy problem, the adiabatic paths are confined to the non-extremal manifold, and therefore, the status of the second and third laws are preserved. Consequently, the extremal sub-manifold corresponds to the adiabatically disconnected boundary of the manifold. In addition, the merger of two extremal Hayward black holes is analyzed.

在这封信中，我们使用 Carathéodory 的热力学方法来构建海沃德黑洞的热力学流形。可逆地表示无穷小的热交换的 Pfaffian 形式被认为是$\delta {问}_{\mathrm{转}}\equiv \mathrm{d}{r}_{秒}-{\mathcal{F}}_H\mathrm{d}升$，之前由 Molina & Villanueva [1] 获得，其中 $r_{秒}$是 Schwarzschild 半径，l是负责 Schwarzschild 黑洞可能正则化的海沃德参数，和${\mathcal{F}}_H$是称为海沃德力的密集变量。通过解决相关的柯西问题，绝热路径被限制在非极值流形中，因此，第二和第三定律的状态得以保留。因此，极值子流形对应于流形的绝热断开边界。此外，还分析了两个极值海沃德黑洞的合并。