Synergistic tests of inflation
  We investigate the possibility of utilising 21cm intensity mapping, optical
galaxy, and Cosmic Microwave Background (CMB) surveys to constrain the power
spectrum of primordial fluctuations predicted by single-field slow-roll
inflation models. Implementing a Fisher forecast analysis, we derive
constraints on the spectral tilt parameter $n_{\rm s}$ and its first and second
runnings $(\alpha_{\rm s},\beta_{\rm s})$. We show that 21cm intensity mapping
surveys with instruments like the Square Kilometre Array, CHIME, and HIRAX, can
be powerful probes of the primordial features. We combine our forecasts with
the ones derived for a COrE-like CMB survey, as well as for a Stage IV optical
galaxy survey similar to Euclid. The synergies between different surveys can be
exploited to rule out a large fraction of the available inflationary models.
