Trans-Planckian Censorship Conjecture and Non-thermal post-inflationary
  history
  The recently proposed Trans-Planckian Censorship Conjecture (TCC) can be used
to constrain the energy scale of inflation. The conclusions however depend on
the assumptions about post-inflationary history of the Universe. E.g. in the
standard case of a thermal post-inflationary history in which the Universe
stays radiation dominated at all times from the end of inflation to the epoch
of radiation matter equality, TCC has been used to argue that the Hubble
parameter during inflation, $H_{\inf}$, is below ${\cal O}(0.1) ~{\rm GeV}$.
Cosmological scenarios with a non-thermal post-inflationary history are
well-motivated alternatives to the standard picture and it is interesting to
find out the possible constraints which TCC imposes on such scenarios. In this
work, we find out the amount of enhancement of the TCC compatible bound on
$H_{\inf}$ if post-inflationary history before nucleosynthesis was non-thermal.
We then argue that if TCC is correct, for a large class of scenarios, it is not
possible for the Universe to have undergone a phase of moduli domination.
