Is asymptotically safe inflation eternal?

Abstract

Recently, based on swampland considerations in string theory, the (no) eternal inflation principle has been put forward. The natural question arises whether similar conditions hold in other approaches to quantum gravity. In this article, the asymptotic safety hypothesis is considered in the context of eternal inflation. As exemplary inflationary models the SU(N) Yang-Mills in the Veneziano limit and various RG-improvements of the gravitational action are studied. The existence of UV fixed point generically flattens the potential and our findings suggest no tension between eternal inflation and asymptotic safety, both in the matter and gravitational sector in contradistinction to string theory. Moreover, the eternal inflation cannot take place in the range of applicability of effective field quantum gravity theory. We employ the analytical relations for eternal inflation to some of the models with single minima, such as Starobinsky inflation, alpha-attractors, or the RG-improved models and verify them with the massive numerical simulations. The validity of these constraints is also discussed for a multi-minima model.

Dimensional Reduction and (Anti) de Sitter Bounds

“…We now take a short break from our dimensional reduction analysis to work out the conditions for eternal inflation in general spacetime dimension d by solving the Fokker-Planck equation, generalizing the computations of [5] (see also [29][30][31][32][33][34][35][36][37][38][39]). 1 In Section 5 below, we will comment briefly on the behavior of the conditions for avoiding eternal inflation under dimensional reduction.…”

Finite Action Principle and Horava-Lifshitz Gravity: early universe, black holes and wormholes

“…Furthermore, it seems that this is in line with the swampland conjectures and the newly proposed finiteamplitude principle [3], making the asymptotically safe quantum gravity to pick initial conditions s.t. inflation ceases to be eternal [64], see also [65,66]. From the point of view of finite action selection principle [1] they are equally good theories, resolving the black holes singularities, assuming that ghost issue is resolved in the latter case.…”

A novel way of constraining the $α$-attractor chaotic inflation through Planck data

“…We observed that during inflation, the number of e-folds shows little variation across the quantum fluctuations, which is to be expected. In Figure 10,11,12 , the variations of scalar (n s ) and tensor (n h ) spectral indies and tensor-to-scalar ratio (r) against mode momenta have been shown. In Figures 13 and 14 we have shown how the results of our calculation fit the Planck 2018 data [33,34] in the n s -r plane.…”

“…Later on and recently, the α-attractor potentials have been extensively applied [7][8][9][10][11][12] in the study of cosmological inflation and also in preheating [13] and reheating [14,15]. Also, the quintessential versions of the α-attractors have also been applied to explain the late time acceleration of the universe [16][17][18][19], as well as in the predictive study of the stage-IV galaxy surveys [20].…”