Editing Renormalization (section)

===Renormalization group fixed points===
The most important information in the RG flow is its '''fixed points'''. A fixed point is defined by the vanishing of the [[beta function (physics)|beta function]] associated to the flow.  Then, fixed points of the renormalization group are by definition scale invariant. In many cases of physical interest scale invariance enlarges to conformal invariance.  One then has a [[conformal field theory]] at the fixed point.

The ability of several theories to flow to the same fixed point leads to [[Universality (dynamical systems)|universality]].

If these fixed points correspond to free field theory, the theory is said to exhibit [[quantum triviality]].  Numerous fixed points appear in the study of [[Lattice gauge theory#Quantum triviality|lattice Higgs theories]], but the nature of the quantum field theories associated with these remains an open question.<ref name="TrivPurs">{{cite journal| author=D. J. E. Callaway | year=1988
| title=Triviality Pursuit: Can Elementary Scalar Particles Exist?| journal=[[Physics Reports]]
|volume=167| issue=5 | pages=241–320| doi=10.1016/0370-1573(88)90008-7
|bibcode = 1988PhR...167..241C | author-link=David J E Callaway
}}</ref>