# Black hole versus cosmological horizon entropy

@article{Davis2003BlackHV,
title={Black hole versus cosmological horizon entropy},
author={Tamara M. Davis and Paul C. W. Davies and C. Lineweaver},
journal={Classical and Quantum Gravity},
year={2003},
volume={20},
pages={2753-2764}
}
• Published 8 May 2003
• Physics
• Classical and Quantum Gravity
The generalized second law of thermodynamics states that entropy always increases when all event horizons are attributed with an entropy proportional to their area. We test the generalized second law by investigating the change in entropy when dust, radiation and black holes cross a cosmological event horizon. We generalize for flat, open and closed Friedmann–Robertson–Walker universes by using numerical calculations to determine the cosmological horizon evolution. In most cases, the loss of…
51 Citations

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## References

SHOWING 1-10 OF 19 REFERENCES

• Physics
• 1977
It is shown that the close connection between event horizons and thermodynamics which has been found in the case of black holes can be extended to cosmological models with a repulsive cosmological
It is shown that the shell has the effect of depressing the temperature of the hole, but that small exchanges of energy between the hole and its environment at the same temperature remain isentropic in the presence of the shell.
It is assumed that the singularities which occur in gravitational collapse are not visible from outside but are hidden behind an event horizon. This means that one can still predict the future
An analogue of Hawking's black hole area theorem (1975) is proved for Friedmann-type cosmological models with event horizons. The generalised second law of thermodynamics is investigated in cases
AbstractIn the classical theory black holes can only absorb and not emit particles. However it is shown that quantum mechanical effects cause black holes to create and emit particles as if they were
• Physics
• 1980
This book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Although the treatment is general, special emphasis is given to the Hawking black hole
According to ’t Hooft the combination of quantum mechanics and gravity requires the three‐dimensional world to be an image of data that can be stored on a two‐dimensional projection much like a
There is strong evidence that the area of any surface limits the information content of adjacent spacetime regions, at $1.4\ifmmode\times\else\texttimes\fi{}{10}^{69}$ bits per square meter. This
• S. Lloyd
• Physics, Computer Science
Physical review letters
• 2002
The Universe is a physical system and the amount of information that the Universe can register and the number of elementary operations that it can have performed over its history are calculated.

### –51 Hawking S W 1972 Commun. Math. Phys. 25 152–66 Hawking S W 1975 Commun. Math. Phys. 43 199–220 Lloyd S

• –51 Hawking S W 1972 Commun. Math. Phys. 25 152–66 Hawking S W 1975 Commun. Math. Phys. 43 199–220 Lloyd S
• 1977