On the Scale of Inflation
  Because the scale of inflation is conformal frame dependent, in order to
fully characterize it one should quote its value in terms of all the
independent equal-time dimensionless ratios in the theory. We argue that when
couplings depend on the inflaton itself, one cannot calculate these ratios in
terms of measurable quantities such as the tensor amplitude and the Planck mass
at present. This uncertainty also becomes manifest when we try to express the
(frame-dependent) inflationary scale in terms of masses that are measurable
today. Although we can calculate inflationary scale in the Einstein frame in
terms of today's Planck mass, we cannot do the same in the Jordan frame. There
are thus grounds to claim that the tensor amplitude does not completely
characterize the scale of inflation.
