Attractors, Bifurcations and Curvature in Multi-field Inflation
  Recent years have seen the introduction of various multi-field inflationary
scenarios in which the curvature and geodesics of the scalar manifold play a
crucial role. We outline a simple description that unifies these different
proposals and discuss their stability criteria. We demonstrate how the
underlying dynamics is governed by an effective potential, whose critical
points and bifurcations determine the late-time behaviour of the system, thus
unifying hyperinflation, angular, orbital and side-tracked inflation.
Interestingly, we show that hyperinflation is a special case of side-tracked
inflation, relying on the enhanced isometries of the hyperbolic manifold. We
provide the explicit coordinate transformation that maps the two models into
each other. Finally, we relax the assumption of a field-space isometry along
the inflationary direction that has been considered a prerequisite in the
literature so far. We explicitly construct inflationary solutions that do not
proceed along a field-space isometry or geodesic and use them to discuss
stability criteria.
