Quintessential $α$-attractor inflation: forecasts for Stage IV galaxy surveys

Abstract

Single-field models of α-attractor quintessential inflation provide a unified picture of the two periods of early-and late-time cosmic acceleration, where both inflation and dark energy are described by a single scalar degree of freedom rolling down a runaway potential. These theoretically well-motivated models have distinct observational predictions that are in agreement with existing cosmological data. We show that the next generation of large-scale structure surveys, even when no other cosmological data sets are considered, will strongly constrain the parameter space of these models, and test them against the standard cosmological model and more conventional non-quintessential inflation. In particular, we expect O(10 −5 −10 −4 ) constraints on the present values of the dark energy equation of state and its time derivative, w 0 and w a . We also forecast more than one order of magnitude tighter constraints on the spectral index of primordial curvature perturbations n s compared to the expectations for the standard model. This demonstrates the powerful synergy between the upcoming large-scale structure probes of inflation and those aiming to measure the tensorto-scalar ratio r through the observation of B-mode polarization of the cosmic microwave background.

Quintessential inflation and cosmological seesaw mechanism: reheating and observational constraints

“…A simple model, constructed from the well-known Lorentzian distribution, was recently presented in [1,2]. We show that the model provides the same spectral index and ratio of tensor to scalar perturbation as the α-attractors models [17,[56][57][58][59][60][61], meaning that it yields a power spectrum of perturbations agreeing with the observation data and is able to depict correctly the current cosmic acceleration. Another property of the model is that it provides a seesaw mechanism.…”

“…which leads to 57 previous one. However, this does not rule out that for other values of the parameters α and β viability could be proved as well.…”