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Astronomy & Astrophysics
Tom Rudelius
Summary: A popular proposal for resolving the Hubble tension involves early dark energy models driven by an axion field. However, these models are tightly constrained by the axion weak gravity conjecture, making it challenging to realize them in a UV complete theory of quantum gravity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
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Astronomy & Astrophysics
Julian Freigang, Dieter Luest, Guo-En Nian, Marco Scalisi
Summary: This study examines the validity of the Swampland Distance Conjecture on prototype geometries of infinite distance limits of Calabi-Yau compactifications and finds that field trajectories leading to cosmic acceleration and featuring rapid turns near the boundary of the moduli space exist in the Swampland. This has significant implications for the realization and consistency of multi-field scenarios in string theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Alberto Salvio
Summary: The recent results of the BICEP and Keck collaborations have placed tight constraints on many inflationary models. One possible way to avoid these constraints is by introducing quadratic-in-curvature terms that can UV complete gravity while respecting stability and unitarity. The predictions of quadratic gravity are computed and compared with the BICEP/Keck constraints in two inflationary scenarios, (critical) Higgs inflation and natural inflation, which are already ruled out in Einstein gravity. It is shown that quadratic gravity can restore agreement with the observational constraints in both scenarios.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
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Astronomy & Astrophysics
David Brizuela, Irene de Leon
Summary: A geometrodynamical quantization of an inflationary universe is considered to estimate quantum-gravity effects for the primordial perturbations, with results showing that both self-interaction and back-reaction from other modes provide corrections of the same order of magnitude to the power spectrum. These quantum-gravity effects introduce characteristic scale-dependence on the expression of the power spectrum.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
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Astronomy & Astrophysics
Damiano Anselmi
Summary: This study investigates primordial cosmology with two scalar fields participating in inflation, revealing the existence of an asymptotically de Sitter cosmic RG flow in two couplings. The importance of quantum gravity theory's predictiveness and the role of RG invariance are highlighted.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
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Astronomy & Astrophysics
Nemanja Kaloper, Morgane Konig, Albion Lawrence, James H. C. Scargill
Summary: This paper revisits two-field hybrid inflation as an effective field theory for low-scale inflation. By focusing on a prototype model by Stewart, it explores the red spectral tilt and constraints of the model, as well as discusses the stability of the model to quantum corrections. The paper suggests that an additional mechanism may be required to ensure stability against corrections from both quantum field theory and quantum gravity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
J. Chojnacki, J. Krajecka, J. H. Kwapisz, O. Slowik, A. Strag
Summary: This article explores the relationship between eternal inflation and the asymptotic safety hypothesis in other approaches to quantum gravity. It reveals that there is no tension between eternal inflation and asymptotic safety in both the matter and gravitational sectors, contrary to string theory. Additionally, it suggests that eternal inflation is not possible within the range of applicability of effective field quantum gravity theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Review
Physics, Multidisciplinary
Marieke van Beest, Jose Calderon-Infante, Delaram Mirfendereski, Irene Valenzuela
Summary: The Swampland program aims to determine the constraints that must be satisfied by an effective field theory to be consistent with a UV embedding in a quantum gravity theory. This article provides a pedagogical introduction to the most important Swampland conjectures, their connections, and their realization in string theory compactifications.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2022)
Article
Astronomy & Astrophysics
Edmund J. Copeland, Francesc Cunillera, Adam Moss, Antonio Padilla
Summary: This study examines field theory monodromy inflation at strong coupling using numerical analysis. It finds that models with uniquely positive Wilson coefficients are ruled out, but models with coefficients that can take on both signs can satisfy current data and strong constraints through term cancellation. Additionally, the study discovers that field theory monodromy models can be enhanced by introducing a mechanism called vacuum energy sequestering, which cancels off radiative corrections to vacuum energy and makes the models more attractive from a theoretical perspective.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Aoumeur Daddi Hammou, Nicola Bartolo
Summary: We investigate the effect of quantum decoherence on inflationary cosmological perturbations, studying its imprint on the statistical properties of fluctuations and the quantum-to-classical transition. We find that cosmic decoherence leads to corrections to the predicted curvature power spectrum and induces a non-vanishing curvature bispectrum. Additionally, we derive a criterion for scale-independent corrections induced by cosmic decoherence and analyze its effect on tensor perturbations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Alberto Nicolis, Federico Piazza, Kenza Zeghari
Summary: This paper revisits rotating cosmologies within the framework of mini-superspace, emphasizing the symmetries and conservation laws. The physical rotation of solid-driven cosmologies is characterized by a conserved angular momentum. The results confirm previous findings regarding the slow decay of anisotropies in solid inflation.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Nilay Bostan
Summary: This study investigates the impact of non-minimal coupling in Palatini gravity on inflationary parameters, focusing on single-field inflation models with non-zero vacuum expectation value. The analysis considers well-known symmetry-breaking potentials and shows their compatibility with recent measurements. Additionally, the study explores the inflationary predictions of selected values in the Palatini formalism.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
David Brizuela, Tomasz Pawlowski
Summary: A study on the dynamics of the inflationary universe model with a quadratic inflaton potential reveals surprising features such as the rapid expansion of the universe during inflation and the accurate semiclassical description of quantum evolution. In the post-inflationary epoch, higher-order quantum corrections wash out the effects of quantum variances, making the description involving only second-order corrections the least accurate.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
M. Drees, B. Najjari
Summary: Long-lived particles are crucial in the universe and their decay processes have significant impacts on the development of the universe. In studying these processes, the consideration of coherence effects and the branching ratios of different particles are necessary.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Cesar Gomez, Raul Jimenez
Summary: Inflationary cosmology predicts a departure from scale invariance in the power spectrum of cosmological scalar perturbations, with a quantum tilt dependent on energy scale. This quantum tilt may lead to a cosmological phase transition and the formation of small mass primordial black holes as dark matter during the early inflationary phase. The entanglement features of de Sitter alpha-vacuum states determine the source and characteristics of the quantum cosmological tilt.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
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Astronomy & Astrophysics
Kari Enqvist, David J. Mulryne, Sami Nurmi
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(2015)
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Astronomy & Astrophysics
Kari Enqvist, Seshadri Nadathur, Toyokazu Sekiguchi, Tomo Takahashi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2015)
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Astronomy & Astrophysics
Kari Enqvist, Toyokazu Sekiguchi, Tomo Takahashi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2016)
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Astronomy & Astrophysics
Vera-Maria Enckell, Kari Enqvist, Sami Nurmi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2016)
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Astronomy & Astrophysics
Kari Enqvist, Sami Nurmi, Stanislav Rusak, David J. Weir
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2016)
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Astronomy & Astrophysics
Kari Enqvist, Robert J. Hardwick, Tommi Tenkanen, Vincent Vennin, David Wands
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
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Astronomy & Astrophysics
Vera-Maria Enckell, Kari Enqvist, Syksy Rasanen, Eemeli Tomberg
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
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Astronomy & Astrophysics
Kari Enqvist, Rose N. Lerner, Tomo Takahashi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2014)
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Astronomy & Astrophysics
Kari Enqvist, Sami Nurmi, Tommi Tenkanen, Kimmo Tuominen
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2014)
Article
Astronomy & Astrophysics
Kari Enqvist, Sami Nurmi, Stanislav Rusak
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2014)
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Astronomy & Astrophysics
Kari Enqvist, Tuukka Meriniemi, Sami Nurmi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2014)
Article
Astronomy & Astrophysics
Vera-Maria Enckell, Kari Enqvist, Syksy Rasanen, Lumi-Pyry Wahlman
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2019)
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Astronomy & Astrophysics
Vera-Maria Enckell, Kari Enqvist, Syksy Rasanen, Lumi-Pyry Wahlman
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
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Astronomy & Astrophysics
Kari Enqvist, Seshadri Nadathur, Toyokazu Sekiguchi, Tomo Takahashi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
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Astronomy & Astrophysics
Kari Enqvist, Till Sawala, Tomo Takahashi
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)