Instant Preheating in Quintessential Inflation with $\alpha$-Attractors
  We investigate a compelling model of quintessential inflation in the context
of $\alpha$-attractors, which naturally result in a scalar potential featuring
two flat regions, the inflationary plateau and the quintessential tail. The
"asymptotic freedom" of $\alpha$-attractors, near the kinetic poles, suppresses
radiative corrections and interactions, which would otherwise threaten to lift
the flatness of the quintessential tail and cause a 5th-force problem
respectively. Since this is a non-oscillatory inflation model, we reheat the
Universe through instant preheating. The parameter space is constrained by both
inflation and dark energy requirements. We find an excellent correlation
between the inflationary observables and model predictions, in agreement with
the $\alpha$-attractors set-up. We also obtain successful quintessence for
natural values of the parameters. Our model predicts potentially sizeable
tensor perturbations (at the level of 1%) and a slightly varying equation of
state for dark energy, to be probed in the near future.
