We give simple examples of weakly coupled or free quantum mechanical systems
that exhibit scale invariance with an anomalous dimension for a conserved
current. In these models scaling as an exact symmetry only emerges in a large N
limit, but it remains as an approximate symmetry even at finite N.Comment: 12 pages, 1 figure; v2: references added; v3: missing factor of z
added in (5.4) and (5.5