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In the last years with the increasing precision in cosmological observations we have been able to establish a standard model of cosmology, the so-called $\Lambda$CDM, but also find some tensions between cosmological probes that are…

宇宙学与河外天体物理 · 物理学 2026-04-07 Jacobo Asorey , Javier de Cruz Pérez

It is known that, through inflation, Planck scale phenomena should have left an imprint in the cosmic microwave background. The magnitude of this imprint is expected to be suppressed by a factor $\sigma^n$ where $\sigma\approx 10^{-5}$ is…

广义相对论与量子宇宙学 · 物理学 2007-05-23 S. Bachmann , A. Kempf

We investigate the recently introduced metastable dark energy (DE) models after the final Planck 2018 legacy release. The essence of the present work is to analyze their evolution at the level of perturbations. Our analyses show that both…

宇宙学与河外天体物理 · 物理学 2020-09-09 Weiqiang Yang , Eleonora Di Valentino , Supriya Pan , Spyros Basilakos , Andronikos Paliathanasis

One problem of the $\Lambda$CDM model is the tension between the $S_8$ found in Cosmic Microwave Background (CMB) experiments and the smaller one obtained from large-scale observations in the late Universe. The $\sigma_8$ quantifies the…

宇宙学与河外天体物理 · 物理学 2021-01-12 David Benisty

The Hubble tension that the standard $\Lambda$CDM model is suffering from can be resolved with pre-recombination early dark energy. We present the first constraint on the tensor-to-scalar ratio $r$ in corresponding Hubble-tension-free…

宇宙学与河外天体物理 · 物理学 2022-09-07 Gen Ye , Yun-Song Piao

Models which address both the Hubble and $S_8$ tensions with the same mechanism generically cause a pre-recombination suppression of the small scale matter power spectrum. Here we focus on two such models. Both models introduce a…

宇宙学与河外天体物理 · 物理学 2024-03-13 Nils Schöneberg , Guillermo Franco Abellán , Théo Simon , Alexa Bartlett , Yashvi Patel , Tristan L. Smith

We discuss the relations between swampland conjectures and observational constraints on both inflation and dark energy. Using the requirement $|\nabla V|\geq c V$, with $c$ as a universal constant whose value can be derived from inflation,…

高能物理 - 理论 · 物理学 2019-08-07 Chien-I Chiang , Jacob M. Leedom , Hitoshi Murayama

The tensions between the values of Hubble constant obtained from the early and the late Universe data pose a significant challenge to modern cosmology. Possible modifications of the flat homogeneous isotropic cosmological {\Lambda}CDM model…

宇宙学与河外天体物理 · 物理学 2021-10-14 S. L. Parnovsky

We investigate the observational constraints on the modified gravity, which combines the $R^{2-q}$ inflation with the power-law (exponential) type of the viable $f(R)$ dark energy models. We discuss the difference between the combined model…

宇宙学与河外天体物理 · 物理学 2015-10-27 Chao-Qiang Geng , Chung-Chi Lee , Shan Lin

In this article, we examine the effects of anisotropy on a model of canonical warm inflation with the power-law potential. The results of this model are compared to Planck satellite observational data. Using a conventional local scalar…

广义相对论与量子宇宙学 · 物理学 2022-05-05 Zahra Ghadiri , Ali Aghamohammadi , Abdollah Refaei

We investigate early dark energy models in the context of the lensing anomaly by considering two different Cosmic Microwave Background (CMB) datasets: a complete Planck, and a second one primarily based on SPTPol and Planck temperature…

宇宙学与河外天体物理 · 物理学 2022-12-20 Balakrishna S. Haridasu , Hasti Khoraminezhad , Matteo Viel

We put forward a primordial scenario to alleviate cosmological tensions, i.e. Hubble ($H_0$) tension and $ S_8 $ tension. Based on flat $\Lambda$CDM, the Bounce-Inflation (BI) scenario gives the results that $ H_0 = 68.60^{+0.40}_{-0.45} \,…

宇宙学与河外天体物理 · 物理学 2025-03-12 Hao-Hao Li , Xin-zhe Zhang , Taotao Qiu

We construct data-driven solutions to the Hubble tension which are perturbative modifications to the fiducial $\Lambda$CDM cosmology, using the Fisher bias formalism. Taking as proof of principle the case of a time-varying electron mass and…

宇宙学与河外天体物理 · 物理学 2023-04-26 Nanoom Lee , Yacine Ali-Haïmoud , Nils Schöneberg , Vivian Poulin

Measurements of $\sigma_8$ from large scale structure observations show a discordance with the extrapolated $\sigma_8$ from Planck CMB parameters using $\Lambda$CDM cosmology. Similar discordance is found in the value of $H_0$ and…

宇宙学与河外天体物理 · 物理学 2017-11-15 Sampurn Anand , Prakrut Chaubal , Arindam Mazumdar , Subhendra Mohanty

We show that emerging tension between the direct astronomical measurements at low redshifts and cosmological parameters deduced from the Planck measurements of the CMB anisotropies can be alleviated if the dark matter consists of two…

宇宙学与河外天体物理 · 物理学 2015-09-30 Z. Berezhiani , A. D. Dolgov , I. I. Tkachev

The present study connects inflation and freeze-in type dark matter (DM) within the same setup. Although the observables in these two phenomena lie at vastly different energy scales, they have been properly handled using the RG running of…

高能物理 - 唯象学 · 物理学 2025-07-01 Sarif Khan , Sourov Roy , Ananya Tapadar

We present updated constraints on the variation of the fine structure constant, $\alpha_{\rm EM}$, and effective electron rest mass, $m_{\rm e}$, during the cosmological recombination era. These two fundamental constants directly affect the…

宇宙学与河外天体物理 · 物理学 2020-05-25 Luke Hart , Jens Chluba

The $R^2$-Higgs inflation is one of the simplest yet best-fit models consistent with Planck data. The higher spectral index $n_s$ recently reported by the combined cosmic microwave background (CMB) data from the Atacama Cosmology Telescope…

高能物理 - 唯象学 · 物理学 2025-12-02 Tanmoy Modak

Due to universality and attractor properties, $\alpha$-attractor quintessential inflation establishes direct relations between inflationary observables such as the scalar tilt $n_s$ and the tensor-to-scalar ratio $r$, and late-time dark…

宇宙学与河外天体物理 · 物理学 2024-11-26 William Giarè , Eleonora Di Valentino , Eric V. Linder , Enrico Specogna

There is a tension between measurements of the amplitude of the power spectrum of density perturbations inferred using the Cosmic Microwave Background (CMB) and directly measured by Large-Scale Structure (LSS) on smaller scales. We show…

宇宙学与河外天体物理 · 物理学 2015-05-20 Richard A. Battye , Tom Charnock , Adam Moss