BLOCK SPIN EFFECTIVE ACTION FOR POLYAKOV LOOPS IN 4D SU(2) LGT

Using a variant of the IMCRG method of Gupta and Cordery, we explicitl y compute majority rule block spin effective actions for the signs of the Polyakov loops in 4D SU(2) finite temperature lattice gauge theori es. To the best of our knowledge, this is the first attempt to compute numerically effective actions for the Polyakov loop degrees of freedo m in 4D SU(2). The most important observations are: 1. The renormaliza tion group flow at the deconfinement transition can be nicely matched with the flow of the 3D Ising model, thus confirming the Svetitsky-Yaf fe conjecture. 2. The IMCRG simulations of the FT SU(2) model have str ongly reduced critical slowing down.