Abstract
Gibbons and Hawking (Phys. Rev. D, 15 (1977) 2738) have shown that the horizon of de Sitter space emits radiation in the same way as the event horizon of the black hole. But actual cosmological horizons are not event horizons, except in de Sitter space. Nevertheless, this paper proves Gibbons' and Hawking's radiation formula as an exact result for any flat space expanding with strictly positive Hubble parameter. The paper gives visual and intuitive insight into why this is the case. The paper also indicates how cosmological horizons are related to the dynamical Casimir effect, which makes experimental tests with laboratory analogues possible.
| Original language | English |
|---|---|
| Article number | 10002 |
| Number of pages | 7 |
| Journal | Europhysics Letters |
| Volume | 135 |
| Issue number | 1 |
| Early online date | 25 Jun 2021 |
| DOIs | |
| Publication status | Published - Jul 2021 |
Funding
This paper is dedicated to the memory of Renaud Parentani. I am most grateful to him for introducing me to the quantum physics of horizons. I also thank D. Bermudez, D. Berechya, and N. Ebel for discussions directly related to this paper. The paper has been supported by the Israel Science Foundation and the Murray B. Koffler Professorial Chair.