坍缩轴子凝聚体模型中由引力和温度驱动的相变
Gravity- and temperature-driven phase transitions in a model for collapsed axionic condensates
AI总结：
本研究利用三次-五次GPPE和SGLPE方程，探究不同温度下轴子气体引力坍缩过程中的构型演化、一级相变与磁滞回线，并拓展研究旋转轴子凝聚体的涡旋及双凝聚体并合动力学。
摘要：
我们展示了如何利用三次-五次Gross-Pitaevskii-Poisson方程（cq-GPPE，三次-五次格罗斯-皮塔耶夫斯基-泊松方程）和三次-五次Stochastic Ginzburg-Landau-Poisson方程（cq-SGLPE，三次-五次随机金兹堡-朗道-泊松方程），研究零温及有限温度$T$下稀薄轴子气体引力坍缩为坍缩轴子凝聚体的过程。在$T=0$时，我们采用球对称密度的高斯Ansatz（高斯假设），推导了可能存在致密轴子凝聚体的参数区间。随后我们突破该假设的限制，利用cq-SGLPE研究$T=0$时轴子凝聚体随引力强度$G$的变化规律。我们证明，随着$G$增大，平衡构型从稀薄轴子气体依次演化为平坦薄片（即$\textit{Zeldovich pancakes}$，泽尔多维奇薄饼）、柱形结构，最终形成球形轴子凝聚体。通过改变$G$我们发现，系统在这些结构间转变时存在一级相变，且观测到与这些相变相关的磁滞回线。我们通过傅里叶截断的cq-GPPE研究了这些状态及其间的转变；同时通过cq-SGLPE得到了$T>0$的热平衡态，这些状态间的转变产生了热驱动一级相变及对应的磁滞回线。最后，我们讨论了如何利用cq-GPPE方法追踪旋转轴子凝聚体以及旋转双轴子凝聚体系统的时空演化；特别地，我们证明前者在大角速度$Ω$下会出现涡旋，后者的双成分并合过程具有丰富动力学，且并合过程中可产生涡旋。
英文摘要：
We show how to use the cubic-quintic Gross-Pitaevskii-Poisson equation (cq-GPPE) and the cubic-quintic Stochastic Ginzburg-Landau-Poisson equation (cq-SGLPE) to investigate the gravitational collapse of a tenuous axionic gas into a collapsed axionic condensate for both zero and finite temperature $T$. At $T=0$, we use a Gaussian Ansatz for a spherically symmetric density to obtain parameter regimes in which we might expect to find compact axionic condensates. We then go beyond this Ansatz, by using the cq-SGLPE to investigate the dependence of the axionic condensate on the gravitational strength $G$ at $T = 0$. We demonstrate that, as $G$ increases, the equilibrium configuration goes from a tenuous axionic gas, to flat sheets or $\textit{Zeldovich pancakes}$, cylindrical structures, and finally a spherical axionic condensate. By varying $G$, we show that there are first-order phase transitions, as the system goes from one of these structures to the next one; we find hysteresis loops that are associated with these transitions. We examine these states and the transitions between these states via the Fourier truncated cq-GPPE; and we also obtain the thermalized $T > 0$ states from the cq-SGLPE; the transitions between these states yield thermally driven first-order phase transitions and their associated hysteresis loops. Finally, we discuss how our cq-GPPE approach can be used to follow the spatiotemporal evolution of a rotating axionic condensate and also a rotating binary-axionic-condensate system; in particular, we demonstrate, in the former, the emergence of vortices at large angular speeds $Ω$ and, in the latter, the rich dynamics of the mergers of the components of this binary system, which can yield vortices in the process of merging.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
