文章基本信息

标题：Fermion RG blocking transformations and IR structure
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作者：T.E Tomboulis ; X. Cheng
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2011
卷号：2011
期号：QCD-TNT-ll
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We explore fermion RG block-spinning transformations on the lattice with the aim of studying the IR structure of gauge theories and, in particular, the existence of IR fixed points for varying fermion content. In the case of light fermions the main concern and difficulty is ensuring locality of any adopted blocking scheme. We discuss the problem of constructing a local blocked fermion action in the background of arbitrary gauge fields. We then discuss the carrying out of accompanying gauge field blocking. In the presence of the blocked fermions implementation of MCRG is not straightforward. By adopting judicious approximations we arrive at an easily implementable approximate RG recursion scheme that allows quick, inexpensive estimates of the location of conformal windows for various groups and fermion representations. We apply this scheme to locate the conformal windows in the case of SU(2) and SU(3) gauge groups. Some of the reasons for the apparent efficacy of this and similar decimation schemes are discussed.