%0 Journal Article
%T Character Expansion, Zeros of Partition Function and $¦È$-term in U(1) Gauge Theory
%A A. S. Hassan
%A M. Imachi
%A N. Tsuzuki
%A H. Yoneyama
%J Physics
%D 1995
%I arXiv
%R 10.1143/PTP.94.861
%X Character expansion developed in real space renormalization group (RSRG) approach is applied to U(1) lattice gauge theory with $\th$-term in 2 dimensions. Topological charge distribution $P(Q)$ is shown to be of Gaussian form at any $\b$(inverse coupling constant). The partition function $Z(\th)$ at large volume is shown to be given by the elliptic theta function. It provides the information of the zeros of partition function as an analytic function of $\ze= e^{i \th}$ ($\th$ = theta parameter). These partition function zeros lead to the phase transition at $\th=\pi$. Analytical results will be compared with the MC simulation results. In MC simulation, we adopt (i)``set method" and (ii)``trial function method".
%U http://arxiv.org/abs/hep-lat/9508011v1