Equation of state for pure SU(3) gauge theory with renormalization group improved action

A lattice study of the equation of state for pure SU(3) gauge theory using a renormalization-group (RG) improved action is presented. The energy density and pressure are calculated on a $16^3\times 4$ and a $32^3\times 8$ lattice employing the integral method. Extrapolating the results to the continuum limit, we find the energy density and pressure to be in good agreement with those obtained with the standard plaquette action within the error of 3-4%. Comparing results from the two actions, a reduction of the cut-off dependence of thermodynamic observables is observed for the RG action at temperatures close to T_c.