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  Does the cosmological horizon have entropy and temperature?

+ 0 like - 0 dislike

Black hole horizons have temperature and entropy. Does this also apply to the cosmological horizon?

Does the cosmological horizon have a temperature, for example? And what is its value?

Is the entropy of the cosmological horizon the same as that of a black hole?

asked Sep 26, 2019 in Astronomy by Maria [ revision history ]
edited Sep 27, 2019

Why not? even the vacuum has temperature.

1 Answer

+ 1 like - 0 dislike

A partial answer only: researching the issue, I found this paper: https://arxiv.org/abs/hep-th/0407255

The paper argues that the temperature of a de Sitter horizon is negative, whereas the entropy and energy remain positive. But the values are not yet clear to me.

answered Sep 28, 2019 by Chri [ no revision ]

On the other hand, all papers on de Sitter space imply that the temperature of the horizon is

$$T =  \frac{\hbar c}{ 2 \pi k} \, \frac{1}{R} $$

which gives $10^{-30}$ K, much less than the 2.7 K of the cosmic background radiation. 

Is it reasonable to speak of the horizon "temperature" and forget about the matter in between?

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