Quintessence Contribution to a Schwarzschild Black Hole Entropy

The quintessence contribution to a Schwarzschild black hole entropy is thoroughly investigated by using the improved brick-wall model. It is found that due to the present of the quintessence, there are two horizons, one is the cosmological horizon, and the other is the black hole horizon. By regulating the cut-off factor ε and the thickness of the thin layer δ, we obtain that the entropy of the system is 1/4 of the sum of the areas of the two event horizons.