# Information Processing

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## Monday, July 19, 2010

### White holes and eternal black holes

New paper! I got interested in this topic because I realized that I didn't understand the quantum aspects of white holes -- i.e., what is the time-reversed equivalent of Hawking radiation (or lack thereof)?

arXiv:1007.2934

Title: White holes and eternal black holes
Authors: Stephen D.H. Hsu
Categories: gr-qc hep-ph hep-th

We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes explode into quasi-thermal radiation.

Here is a figure from the paper:

Caption: A white hole spacetime. We impose the condition that past null infinity $\cal{J}_-^{\rm wh}$ is in the vacuum state -- there is no incoming radiation from the far past. The dotted black line is the initial singularity, and the dashed blue line is the path of a null ray on the anti-horizon. The curved line indicates matter which explodes out of the hole. The dashed black lines refer to modes discussed in the text, which we can think of as originating from the white hole, its ejecta, or from the past, $\cal{J}_-^{\rm wh}$.