[论文解读] Back-reaction of the Hawking radiation flux on a gravitationally collapsing star II: Fireworks instead of firewalls

Laura Mersini–Houghton, Harald Pfeiffer|arXiv (Cornell University)|Sep 5, 2014

Quantum Electrodynamics and Casimir Effect被引用 5

一句话总结

本文通过将霍金辐射的负能量通量建模为向内传播的通量，以减缓并逆转坍缩，研究了霍金辐射对引力坍缩星体的反作用。在全4维爱因斯坦方程与流体动力学方程下，初始量子态为昂鲁真空，结果表明恒星在不形成事件视界或奇点的情况下蒸发，火墙被‘烟花’现象取代——即一种动态、无视界的蒸发过程。

ABSTRACT

A star collapsing gravitationally into a black hole emits a flux of radiation, known as Hawking radiation. When the initial state of a quantum field on the background of the star, is placed in the Unruh vacuum in the far past, then in the exterior Hawking radiation corresponds to a flux of positive energy radiation travelling outwards from near the surface to future infinity. Based on pair creation, the evaporation of the collapsing star can be equivalently described by the absorption of an ingoing negative energy flux of radiation travelling towards the center of the star. Here, we are interested in the evolution of the star during its collapse. Thus we include the backreaction of the negative energy Hawking flux in the interior geometry of the collapsing star when writing the full 4-dimensional Einstein and hydrodynamic equations. Hawking radiation emitted before the star passes through its Schwarzschild radius slows down and reverses the collapse of the star. The star evaporates without forming an horizon or a singularity. This study provides a more realistic investigation than the one first presented in [1], since the backreaction of Hawking radiation flux on the collapsing star is studied in the case when the initial state of the field is in Unruh's vacuum.

研究动机与目标

• 通过完整的4维爱因斯坦方程与流体动力学方程，对霍金辐射对坍缩恒星的反作用进行建模。
• 研究霍金辐射的负能量通量是否能阻止并逆转引力坍缩。
• 确定当初始量子态为昂鲁真空时，是否形成黑洞视界或奇点。
• 通过在动态坍缩中引入量子场反作用，提供比火墙情景更现实的替代方案。

提出的方法

• 通过粒子对产生过程，将霍金辐射通量建模为向内传播的负能量通量。
• 求解与坍缩恒星耦合的完整四维爱因斯坦方程。
• 将昂鲁真空用作场在遥远过去的初始量子态。
• 动态演化系统，以追踪负能量通量如何影响恒星内部几何与坍缩动力学。
• 分析恒星半径与能量密度的演化，以检测视界形成或坍缩反转。

实验结果

研究问题

• RQ1 霍金辐射的负能量通量反作用是否能阻止引力坍缩过程中事件视界的形成？
• RQ2 恒星是否能因霍金辐射的能量通量而反转其坍缩，导致无视界的蒸发？
• RQ3 在量子反作用下，初始昂鲁真空态如何影响坍缩恒星的动力学？
• RQ4 当完全包含量子辐射效应时，恒星的最终状态性质是什么？

主要发现

• 霍金辐射的负能量通量减缓并最终逆转了恒星的引力坍缩。
• 恒星完全蒸发，未形成事件视界或时空奇点。
• 最终结果是一种动态、无视界的演化过程，类似于‘烟花’而非具有火墙的黑洞。
• 在完整的4D爱因斯坦-流体动力学框架中引入反作用后，形成了非奇点、非视界的蒸发情景。