Equation of state at finite density in two-flavor QCD with improved   Wilson quarks
  We study the equation of state in two-flavor QCD at finite temperature and density. Simulations are made with the RG-improved gluon action and the clover-improved Wilson quark action. Along the lines of constant physics for $m_{\rm PS}/m_{\rm V} = 0.65$ and 0.80, we compute the derivatives of the quark determinant with respect to the quark chemical potential $\mu_q$ up to the fourth order at $\mu_q=0$. We adopt several improvement techniques in the evaluation. We study thermodynamic quantities and quark number susceptibilities at finite $\mu_q$ using these derivatives. We find enhancement of the quark number susceptibility at finite $\mu_q$, in accordance with previous observations using staggered-type quarks. This suggests the existence of a nearby critical point. 
S. Aoki, S. Ejiri, T. Hatsuda, N. Ishii, K. Kanaya, Y. Maezawa, N.   Ukita, and T. Umeda (WHOT-QCD Collaboration)