Hawking radiation from the cosmological horizon in a FRW universe

Understand

It is well known that there is a Hawking radiation from the cosmological horizon of the de-sitter spacetime, and the de-sitter spacetime can be a special case of a FRW universe.

• Therefore, there may be a corresponding Hawking radiation in a FRW universe.
• Indeed, there have been several clues showing that there is a Hawking radiation from the apparent horizon of a FRW universe.
• In our paper, however, we find that the Hawking radiation may come from the cosmological horizon.