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arXiv · 0704.0793

Friedmann Equations and Thermodynamics of Apparent Horizons

Yungui Gong·Anzhong Wang
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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 $dE=T_AdS_A$ 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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Yungui Gong, Anzhong Wang. 2007-11-14. Friedmann Equations and Thermodynamics of Apparent Horizons. https://doi.org/10.1103/physrevlett.99.211301

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