球对称模型：在各向异性压力模型中分离膨胀和收缩
Spherically symmetric models: separating expansion from contraction in models with anisotropic pressures
摘要：
我们研究了具有各向异性流体的球对称时空，讨论了分离膨胀区和坍缩区的分壳的存在性和稳定性。我们发现，划分壳是由压力梯度，各向同性和各向异性，和由Misner-Sharpe质量内的分离壳和压力通量引起的字段的强度之间的关系定义的。这种平衡是定义局部平衡条件的托尔曼-奥本海默-阿斯托夫平衡条件的推广，但在Misner-Sharpe质量的定义下也传达了非局部特征。我们提出了一个特定的解决方案，尘埃和辐射，提供了一个说明我们的结果。
英文摘要：
We investigate spherically symmetric spacetimes with an anisotropic fluid and discuss the existence and stability of a dividing shell separating expanding and collapsing regions. We find that the dividing shell is defined by a relation between the pressure gradients, both isotropic and anisotropic, and the strength of the fields induced by the Misner-Sharpe mass inside the separating shell and by the pressure fluxes. This balance is a generalization of the Tolman-Oppenheimer- Volkoff equilibrium condition which defines a local equilibrium condition, but conveys also a non- local character given the definition of the Misner-Sharpe mass. We present a particular solution with dust and radiation that provides an illustration of our results.
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。
