Dark Energy in Global Brane Universe

We discuss the exact solutions of brane universes and the results indicate the Friedmann equations on the branes are modified with a new density term. Then, we assume the new term as the density of dark energy. Using Wetterich's parametrization equation of state (EOS) of dark energy, we obtain the new term varies with the red-shift z. Finally, the evolutions of the mass density parameter $\Omega_2$, dark energy density parameter $\Omega_x$ and deceleration parameter q_2 are studied.