Scalar Field Theory at Finite Temperature in D=2+1
We discuss the $ϕ^6 $ theory defined in $D=2+1$-dimensional space-time and assume that the system is in equilibrium with a thermal bath at temperature $β^{-1}$. We use the $ 1/N $ expansion and the method of the composite operator (CJT) for summing a large set of Feynman graphs.We demonstrate explicitly the Coleman-Mermin-Wagner theorem at finite temperature.
hep-th↗