标题： 度规变量下有效的量子引力坍缩：$\barμ$方案 显示英文标题

标题： Effective Quantum Gravitational Collapse in Metric Variables: The $\barμ$ Scheme

摘要： 我们利用度量变量研究了如何使用圈量子引力（LQG）的$\bar{\mu}$方案构建Oppenheimer-Snyder引力坍缩的有效理论。两种模型——平坦模型和球对称模型——的坍缩都被分析了。在这两种情况下，有效理论都能避免奇点的形成。这种现象的原因在于引力场的应力-能量张量中存在一个负压项。对该负压进行了分析，并得出结论认为，有效的聚合物模型是负压出现的原因。此外，还对这两种模型的解进行了刻画，表明坍缩被改变并避免，取而代之的是从黑洞态向白洞态的转变，这一转变发生在坍缩达到普朗克尺度时。 显示英文摘要

摘要： We study, using the metric variables, how an effective theory for the Oppenheimer-Snyder gravitational collapse can be built with the $\bar{\mu}$ scheme from Loop Quantum Gravity (LQG). The collapse is analyzed for both the flat and spherical models. In both scenarios the effective theory make possible to avoid the formation of the singularity. The source of this is found in the presence of a negative pressure term inside the stress-energy tensor of the gravitational field. This pressure is analyzed and is concluded that the effective polymer model is the reason why the negative pressure appears. A characterization of the solutions for both models is also carried out, showing that the collapse is altered and avoided in favor of a transition from a black hole state to a white hole one, transition that occurs when the collapse has reached a Planckian regime.