  The Wilkinson Microwave Anisotropy Probe microwave background data suggest
that the primordial spectrum of scalar curvature fluctuations is suppressed at
small wavenumbers. We propose a UV/IR mixing effect in small-field inflationary
models that can explain the observable deviation in WMAP data from the
concordance model. Specifically, in inflationary models where the inflaton
couples to an asymptotically free gauge theory, the radiative corrections to
the effective inflaton potential can be anomalously large. This occurs for
small values of the inflaton field which are of the order of the gauge theory
strong coupling scale. Radiative corrections cause the inflaton potential to
blow up at small values of the inflaton field. As a result, these corrections
can violate the slow-roll condition at the initial stage of the inflation and
suppress the production of scalar density perturbations.
