I was reading a paper the other day that was discussing NFL behavior in heavy fermion systems. There was a phase diagram that was plotted as a function of temperature vs. doping. In the diagram, there was a transition from a spin glass state to an NFL phase which occurred as a second order T=0 phase transition across a quantum critical point. I am familiar with the basic idea of a quantum phase transition. Namely, whereas thermal phase transitions occur due to the rise of thermal fluctiations, quantum phase transitions occur due to the fact that even when the temperature is suppressed to zero, quantum fluctations due to Heisenbergs uncertainty principle are sufficient to drive the change of state. So here's my question: How can the miniscule quantum fluctions suffice to cause a change in state. I tried looking at Wiki, and it said something about the fluctations being "scale invariant" with interactions extending across the entire system. I am not sure what they entirely mean by this nor how this could possibly occur. Could someone please explain. I would greatly appreciate it.