The nature of the different zero-temperature phases in discrete   two-dimensional spin glasses: Entropy, universality, chaos and cascades in   the renormalization group flow
  The properties of discrete two-dimensional spin glasses depend strongly on the way the zero-temperature limit is taken. We discuss this phenomenon in the context of the Migdal-Kadanoff renormalization group. We see, in particular, how these properties are connected with the presence of a cascade of fixed points in the renormalization group flow. Of particular interest are two unstable fixed points that correspond to two different spin-glass phases at zero temperature. We discuss how these phenomena are related with the presence of entropy fluctuations and temperature chaos, and universality in this model. 
Thomas Jorg, Florent Krzakala
cond-mat.dis-nn cond-mat.stat-mech