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arxiv: 0704.0793 · v2 · submitted 2007-04-06 · ✦ hep-th · astro-ph· gr-qc

Friedmann Equations and Thermodynamics of Apparent Horizons

classification ✦ hep-th astro-phgr-qc
keywords apparentfriedmannhorizonthermodynamicsequationfirsttheoriescoincidence
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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 $dE=T_AdS_A$ 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.

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Cited by 2 Pith papers

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