Hyperinflation generalised: from its attractor mechanism to its tension
  with the `swampland conjectures'
  In negatively curved field spaces, inflation can be realised even in steep
potentials. Hyperinflation invokes the `centrifugal force' of a field orbiting
the hyperbolic plane to sustain inflation. We generalise hyperinflation by
showing that it can be realised in models with any number of fields
($N_f\geq2$), and in broad classes of potentials that, in particular, don't
need to be rotationally symmetric. For example, hyperinflation can follow a
period of radial slow-roll inflation that undergoes geometric destabilisation,
yet this inflationary phase is not identical to the recently proposed scenario
of `side-tracked inflation'. We furthermore provide a detailed proof of the
attractor mechanism of (the original and generalised) hyperinflation, and
provide a novel set of characteristic, explicit models. We close by discussing
the compatibility of hyperinflation with observations and the recently much
discussed `swampland conjectures'. Observationally viable models can be
realised that satisfy either the `de Sitter conjecture' ($V'/V\gtrsim 1$) or
the `distance conjecture' ($\Delta \phi \lesssim 1$), but satisfying both
simultaneously brings hyperinflation in some tension with successful reheating
after inflation. However, hyperinflation can get much closer to satisfying all
of these criteria than standard slow-roll inflation. Furthermore, while the
original model is in stark tension with the weak gravity conjecture,
generalisations can circumvent this issue.
