Probing inflation models with gravitational waves
  A direct detection of primordial gravitational waves is the ultimate probe
for any inflation model. While current CMB bounds predict the generic
scale-invariant gravitational wave spectrum from slow-roll inflation to be
below the reach of upcoming gravitational wave interferometers, this prospect
may dramatically change if the inflaton is a pseudoscalar. In this case, a
coupling to any abelian gauge field leads to a tachyonic instability for the
latter and hence to a new source of gravitational waves, directly related to
the dynamics of inflation. In this contribution we discuss how this setup
enables the upcoming gravitational wave interferometers advanced LIGO/VIRGO and
eLISA to probe the microphysics of inflation, distinguishing between different
universality classes of single-field slow-roll inflation models. We find that
the prime candidate for an early detection is a Starobinsky-like model.
