Non-Standard Primordial Clocks from Dynamical Mass in Alternative to
  Inflation Scenarios
  In the primordial universe, oscillations of heavy fields can be considered as
standard clocks to measure the expansion or contraction history of the
universe. Those standard clocks provide a model-independent way of
distinguishing inflation and alternative scenarios. However, the mass of the
heavy fields may not be a constant mass, but rather mass dynamically generated
by non-minimal coupling to the Ricci scalar, or self-interactions. In the case
of dynamically generated mass, the mass of the heavy field is generically of
order Hubble, and thus is time-dependent in alternative to inflation scenarios.
We show that such dynamically generated mass terms can be considered as
non-standard primordial clocks for alternative to inflation, providing similar
oscillatory frequencies as standard clocks of inflation. Additional information
on scale dependence can distinguish such non-standard clocks from standard
clocks.
