Construction of the Gibbs measures associated with Euclidean quantum field theory with various polynomial interactions in the Wick renormalizable regime

Abstract: In this paper, we consider the Gibbs measures associated with Euclidean quantum field theory with polynomial-type of interactions on the torus. We observe the (non-)normalizability of the multivariate version of $P(\Phi)_2$ models by the variational method. Moreover, we extend this setting to the "fractional model" in the "Wick renormalizable regime": the base Gaussian measure has the inverse of the fractional power of the Laplacian as its covariance with the restriction that the Wick products that appear during the renormalization procedure are all well-defined. After working on the issue in a general setting, we also examine some specific examples as an application.