Is asymptotically safe inflation eternal?

Chojnacki, Jan; Krajecka, Julia; Kwapisz, Jan; Słowik, Oskar; Strąg, Artur

doi:10.1088/1475-7516/2021/04/076

Cited by 10 publications

(8 citation statements)

References 103 publications

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“…The similar results were obtained in the (R + R 2 + R 3 ) model[19] 5. It might be possible to get a flat potential for very large inflaton field values via a resummation of all higher-curvature corrections, e.g., in the framework of asymptotically-safe quantum gravity[48,49].…”

supporting

confidence: 77%

Analytic extensions of Starobinsky model of inflation

Ivanov

Ketov

Pozdeeva

et al. 2022

J. Cosmol. Astropart. Phys.

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We study several extensions of the Starobinsky model of inflation, which obey all observational constraints on the inflationary parameters, by demanding that both the inflaton scalar potential in the Einstein frame and the F(R) gravity function in the Jordan frame have the explicit dependence upon fields and parameters in terms of elementary functions. Our models are continuously connected to the original Starobinsky model via changing the parameters. We modify the Starobinsky (R + R 2) model by adding an R 3-term, an R 4-term, and an R 3/2-term, respectively, and calculate the scalar potentials, the inflationary observables and the allowed limits on the deformation parameters by using the latest observational bounds. We find that the tensor-to-scalar ratio in the Starobinsky model modified by the R 3/2-term significantly increases with raising the parameter in front of that term. On the other side, we deform the scalar potential of the Starobinsky model in the Einstein frame in powers of y = exp(-√(2/3)ϕ/M Pl), where ϕ is the canonical inflaton (scalaron) field, calculate the corresponding F(R) gravity functions in the two new cases, and find the restrictions on the deformation parameters in the lowest orders with respect to the variable y that is physically small during slow-roll inflation.

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supporting

confidence: 77%

Analytic extensions of Starobinsky model of inflation

Ivanov

Ketov

Pozdeeva

et al. 2022

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

show abstract

“…Combined with earlier results, our investigation backs up fully the topological phase conjecture hence making inflation redundant. Furthermore, it seems that this is in line with the swampland conjectures and the newly proposed finite-amplitude principle [4], making the asymptotically safe quantum gravity to pick initial conditions such that inflation ceases to be eternal [82], see also [83,84].…”

Section: Conclusion and Discussionsupporting

confidence: 68%

Finite action principle and Hořava-Lifshitz gravity: Early universe, black holes, and wormholes

Chojnacki

Kwapisz

2021

Phys. Rev. D

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In this work, we elaborate on the finite action in the framework of Hořava-Lifshitz gravity. Assuming the finite action principle, we show that the beginning of the Universe is flat and homogeneous. Depending on the version of the theory, different cosmological scenarios are possible. Furthermore, we show that the Hořava-Lifshitz gravity action selects only the regular black-hole spacetimes since the singular black holes possess infinite action. We also comment on the possibility of traversable wormholes in theories with higher-curvature invariants. The possible cosmological solutions in Hořava-Lifshitz and quadratic gravity are similar, proving that the finite action principle is not model sensitive.

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“…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 [31][32][33][34][35][36][37][38][39][40][41][42]). 1 In section 5 below, we will comment briefly on the behavior of the conditions for avoiding eternal inflation under dimensional reduction.…”

Section: Interlude: Eternal Inflation In Higher Dimensionsmentioning

confidence: 99%

Dimensional reduction and (Anti) de Sitter bounds

Rudelius

2021

J. High Energ. Phys.

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Dimensional reduction has proven to be a surprisingly powerful tool for delineating the boundary between the string landscape and the swampland. Bounds from the Weak Gravity Conjecture and the Repulsive Force Conjecture, for instance, are exactly preserved under dimensional reduction. Motivated by its success in these cases, we apply a similar dimensional reduction analysis to bounds on the gradient of the scalar field potential V and the mass scale m of a tower of light particles in terms of the cosmological constant Λ, which ideally may pin down ambiguous O(1) constants appearing in the de Sitter Conjecture and the (Anti) de Sitter Distance Conjecture, respectively. We find that this analysis distinguishes the bounds $$ \left|\nabla V\right|/V\ge \sqrt{4/\left(d-2\right)} $$ ∇ V / V ≥ 4 / d − 2 , m ≲ |Λ|1/2, and m ≲ |Λ|1/d in d-dimensional Planck units. The first of these bounds is equivalent to the strong energy condition in Einstein-dilaton gravity and precludes accelerated expansion of the universe. It is almost certainly violated in our universe, though it may apply in asymptotic limits of scalar field space. The second bound cannot be satisfied in our universe, though it is saturated in supersymmetric AdS vacua with well-understood uplifts to 10d/11d supergravity. The third bound likely has a limited range of validity in quantum gravity as well, so it may or may not apply to our universe. However, if it does apply, it suggests a possible relation between the cosmological constant and the neutrino mass, which (by the see-saw mechanism) may further provide a relation between the cosmological constant problem and the hierarchy problem. We also work out the conditions for eternal inflation in general spacetime dimensions, and we comment on the behavior of these conditions under dimensional reduction.

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Is asymptotically safe inflation eternal?

Cited by 10 publications

References 103 publications

Analytic extensions of Starobinsky model of inflation

Analytic extensions of Starobinsky model of inflation

Finite action principle and Hořava-Lifshitz gravity: Early universe, black holes, and wormholes

Dimensional reduction and (Anti) de Sitter bounds

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