Rong-Gen Cai and Sang Pyo Kim JHEP02(2005)050 doi:10.1088/1126-6708/2005/02/050
Rong-Gen Cai1,2 and Sang Pyo Kim3,4
Show affiliationsApplying the first law of thermodynamics to the apparent horizon of a Friedmann-Robertson-Walker universe and assuming the geometric entropy given by a quarter of the apparent horizon area, we derive the Friedmann equations describing the dynamics of the universe with any spatial curvature. Using entropy formulae for the static spherically symmetric black hole horizons in Gauss-Bonnet gravity and in more general Lovelock gravity, where the entropy is not proportional to the horizon area, we are also able to obtain the Friedmann equations in each gravity theory. We also discuss some physical implications of our results.
04.70.Dy Quantum aspects of black holes, evaporation, thermodynamics
Issue 02 (February 2005)
Received 10 January 2005, accepted for publication 14 February 2005
Published 16 March 2005
Rong-Gen Cai and Sang Pyo Kim JHEP02(2005)050