Center for Theoretical Physics and Department of Physics, University of California, Berkeley, California 94720-7300, USA and Lawrence Berkeley National Laboratory, Berkeley, California 94720-8162, USA.
Phys Rev Lett. 2014 Jan 31;112(4):041102. doi: 10.1103/PhysRevLett.112.041102. Epub 2014 Jan 28.
If information escapes from an evaporating black hole, then field modes just outside the horizon must be thermally entangled with distant Hawking radiation. But for an infalling observer to find empty space at the horizon, the same modes would have to be entangled with the black hole interior. Thus, unitarity appears to require a "firewall" at the horizon. Identifying the interior with the distant radiation promises to resolve the entanglement conflict and restore the vacuum. But the map must adjust for any interactions, or else the firewall will reappear if the Hawking radiation scatters off the cosmic microwave background. Such a map produces a "frozen vacuum," a phenomenon that is arguably worse than a firewall. An infalling observer is unable to excite the vacuum near the horizon. This allows the horizon to be locally detected and so violates the equivalence principle.
如果信息从蒸发的黑洞中逃逸出来，那么视界之外的场模式就必须与遥远的霍金辐射热纠缠在一起。但是，对于一个下落的观察者来说，要想在视界处找到空的空间，相同的模式就必须与黑洞内部纠缠在一起。因此，幺正性似乎要求在视界处存在“防火墙”。将内部与遥远的辐射联系起来有望解决纠缠冲突并恢复真空。但是，该映射必须针对任何相互作用进行调整，否则，如果霍金辐射散射到宇宙微波背景中，防火墙就会重新出现。这样的映射产生了一个“冻结的真空”，这一现象比防火墙更糟糕。一个下落的观察者无法激发视界附近的真空。这使得视界可以在局部被探测到，从而违反等效原理。
