AUTHOR=Boettcher Stefan TITLE=Renormalization Group for Critical Phenomena in Complex Networks JOURNAL=Frontiers in Physiology VOLUME=volume 2 - 2011 YEAR=2011 URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2011.00102 DOI=10.3389/fphys.2011.00102 ISSN=1664-042X ABSTRACT= We discuss the behavior of statistical models on a novel class of complex ``Hanoi'' networks. Such modeling is often the cornerstone for the understanding of many dynamical processes in complex networks. Hanoi networks are special because they integrate small-world hierarchies common to many social and economical structures with the inevitable geometry of the real work these structures exist in. In addition, their design allows \emph{exact} results to be obtained with the venerable renormalization group (RG). Our treatment will provide a detailed, pedagogical introduction to RG. In particular, we will study the Ising model with RG, for which the fixed-points are determined and the RG-flow is analyzed. We show that the small-world bonds result in non-universal behavior. It is shown that a diversity of different behaviors can be observed with seemingly small changes in the structure of hierarchical networks generally, and we provide a general theory to describe our findings.