Learning of today:

1. Critical point marks for end of second order phase transition. At second order phase transitions the double derivative of free energy diverges. So, the critical point is the end point of second order phase transition line.
2. If you plot gT vs T and g^{2T vs T, the relation is linear, which says that the effective masses of EQCD(~gT) and MQCD (~g}2T) increases which implies that correlation length decreases with T.