Yang-Yang anomaly

The Yang-Yang anomaly provides (Eq. 3):

$C_V=VT{\frac{{\partial }^{2}p}{\partial T^2}|}_V-NT{\frac{{\partial }^2\mu }{\partial T^2}|}_V$

where $C_V$ is the heat capacity at constant volume and $\mu$ is the chemical potential. Given that experimentally it is found that $C_V$ diverges at the critical temperature this implies that either ${\partial }^{2}p/\partial T^2$ or ${\partial }^2\mu /\partial T^2$, or both, diverge as $T\to T_c^{-}$. Fisher and Orkoulas showed that both terms diverge.