# 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} }

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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Our Universe is expected to finally approach a de Sitter universe whose horizon is considered to be in thermal equilibrium. In the present article, both the energy stored on the horizon and its…

## References

SHOWING 1-10 OF 19 REFERENCES

### Cosmological Event Horizons, Thermodynamics, and Particle Creation

- 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…

### Gravitational entropy: Beyond the black hole.

- PhysicsPhysical review. D, Particles and fields
- 1986

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.

### Black holes in general relativity

- Physics
- 1972

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…

### Cosmological horizons and entropy

- Physics
- 1988

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…

### Particle creation by black holes

- Physics
- 1975

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…

### Quantum Fields in Curved Space

- 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…

### The world as a hologram

- Physics
- 1994

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…

### The Holographic principle

- Physics
- 2002

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…

### Computational capacity of the universe.

- Physics, Computer SciencePhysical 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