Systematic unification of the partition functions of various field theories in a two dimensional classical $\phi^4$ model
Mohammad Hossein Zarei, Yahya Khalili
Abstract
We show that the partition functions of several field theories with different symmetries and in various dimensions are equal to the partition function of a two-dimensional (2D) classical $\phi^4$ field theory model. Although the completeness of 2D $\phi^4$ model has been already proved by introducing a quantum formalism for the partition functions, in this paper we study it in a fundamental systematic approach with purely mathematical basis to re-derive such completeness in a general manner. Due to generality, such re-derivation will lead to more clarification of the result for other communities of physics as well as quantum information theorists. Furthermore, our proof of the completeness has an important advantage that is a step-by-step proof which is supported by some graphical transformations. Specifically, we consider discrete version of field theories on lattices with arbitrary dimensions where they are defined as arbitrary polynomial functions of fields with different symmetries. Then we give a set of simple graphical transformations on such field theories to convert them to a classical $\phi^4$ field theory on a 2D square lattice with the same partition function.