Friedmann Equations and Thermodynamics of Apparent Horizons

Abstract

With the help of a masslike function which has dimension of energy and equals to the Misner-Sharp mass at the apparent horizon, we show that the first law of thermodynamics of the apparent horizon $dE=T_{A}d{S}_A$ can be derived from the Friedmann equation in various theories of gravity, including the Einstein, Lovelock, nonlinear, and scalar-tensor theories. This result strongly suggests that the relationship between the first law of thermodynamics of the apparent horizon and the Friedmann equation is not just a simple coincidence, but rather a more profound physical connection.

no figures, V2: re-organized and re-writtend, main results and conclusion unchanged, Phys. Rev. Lett. in press

References in corpus (4)

• Thermodynamical Properties of Apparent Horizon in Warped DGP Braneworld
• Deep Connection Between Thermodynamics and Gravity in Gauss-Bonnet Braneworld
• Einstein's equations as a thermodynamic identity: The cases of stationary axisymmetric horizons and evolving spherically symmetric horizons
• First law of thermodynamics and Friedmann-like equations in braneworld cosmology

Cited by in corpus (6)

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• Thermodynamics of Apparent Horizon in Brane World Scenarios
• Thermodynamics on the apparent horizon in generalized gravity theories
• Generalized second law in modified theory of gravity
• Cosmological Imprint of the Second Law of Thermodynamics