More Axions from Strings
  We study the contribution to the QCD axion dark matter abundance that is
produced by string defects during the so-called scaling regime. Clear evidence
of scaling violations is found, the most conservative extrapolation of which
strongly suggests a large number of axions from strings. In this regime,
nonlinearities at around the QCD scale are shown to play an important role in
determining the final abundance. The overall result is a lower bound on the QCD
axion mass in the post-inflationary scenario that is substantially stronger
than the naive one from misalignment.
