Lattice QCD equation of state : improving the differential method

We propose an improvement of the differential method for the computation of the equation of state of QCD from lattice simulations. In contrast to the earlier differential method our technique yields positive pressure for all temperatures including in the transition region. Employing it on temporal lattices of 8, 10 and 12 sites and by extrapolating to zero lattice spacing we obtained the pressure, energy density, entropy density, specific heat and speed of sound in quenched QCD for 0.9 < T/Tc < 3. A comparison of our results is made with those from the dimensional reduction approach and a conformal symmetric theory at high-temperature.