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In this paper we explore the potential effects of DM annihilations on the cosmological recombination spectrum. With this example we want to demonstrate that the cosmological recombination spectrum in principle is sensitive to details…

宇宙学与河外天体物理 · 物理学 2015-05-14 J. Chluba

The $\Lambda$CDM model provides a good fit to most astronomical observations but harbors large areas of phenomenology and ignorance. With the improvements in the precision and number of observations, discrepancies between key cosmological…

宇宙学与河外天体物理 · 物理学 2023-02-15 Jian-Ping Hu , Fa-Yin Wang

Many attempts to solve the Hubble tension with extended cosmological models combine an enhanced relic radiation density, acting at the level of background cosmology, with new physical ingredients affecting the evolution of cosmological…

宇宙学与河外天体物理 · 物理学 2019-10-16 Nils Schöneberg , Julien Lesgourgues , Deanna C. Hooper

Motivated by the current status of the cosmological observations and significant tensions in the estimated values of some key parameters assuming the standard $\Lambda$CDM model, we propose a simple but radical phenomenological emergent…

宇宙学与河外天体物理 · 物理学 2020-01-14 Xiaolei Li , Arman Shafieloo

A simple and minimal extension of the standard cosmological $\Lambda$CDM model in which dark matter experiences an additional long-range scalar interaction is demonstrated to alleviate the long lasting Hubble-tension while letting…

宇宙学与河外天体物理 · 物理学 2024-05-08 Cyril Pitrou , Jean-Philippe Uzan

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

Early dark energy solutions to the Hubble tension introduce an additional scalar field which is frozen at early times but becomes dynamical around matter-radiation equality. In order to alleviate the tension, the scalar's share of the total…

高能物理 - 唯象学 · 物理学 2025-04-01 Marc Kamionkowski , Anubhav Mathur

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

The recent measurements of the Hubble constant based on the standard $\Lambda$CDM cosmology reveal an underlying disagreement between the early-Universe estimates and the late-time measurements. Moreover, as these measurements improve, the…

综合物理 · 物理学 2020-11-25 Ram Gopal Vishwakarma

Local measurements of the Hubble parameter are increasingly in tension with the value inferred from a $\Lambda$CDM fit to the cosmic microwave background (CMB) data. In this paper, we construct scenarios in which evolving scalar fields…

宇宙学与河外天体物理 · 物理学 2023-10-13 Prateek Agrawal , Francis-Yan Cyr-Racine , David Pinner , Lisa Randall

The observed discrepancy of the Hubble parameter measurements in the local universe with the cosmic microwave background (CMB) data may indicate a new physics. It is vital to test the alternative models that reconcile the Hubble tension…

宇宙学与河外天体物理 · 物理学 2021-09-03 Hossein Moshafi , Shant Baghram , Nima Khosravi

Recent DESI BAO measurements, combined with CMB data, reveal a tension within the $\Lambda$CDM model that leads to a discrepancy between cosmological and laboratory bounds on the summed neutrino mass. We show that a recoupled interacting…

宇宙学与河外天体物理 · 物理学 2026-05-19 Ravi Kumar Sharma , Maria Archidiacono , Julien Lesgourgues

A family of simple and minimal extensions of the standard cosmological $\Lambda$CDM model in which dark matter experiences an additional long-range scalar interaction is demonstrated to alleviate the long lasting Hubble-tension while…

宇宙学与河外天体物理 · 物理学 2024-05-08 Jean-Philippe Uzan , Cyril Pitrou

I show that early-time (pre-recombination) solutions to the Hubble tension are generically expected to increase the preferred baryon density $\omega_b$. This puts these models in tension with Big Bang Nucleosynthesis (BBN), as measurements…

宇宙学与河外天体物理 · 物理学 2026-04-08 Cara Giovanetti

An excess density of quasiparticles is widely observed in superconducting films. This excess causes performance degradation in a variety of superconducting devices, including decoherence in qubits. In this Letter, we evaluate the hypothesis…

超导电性 · 物理学 2025-07-08 Eva Gurra , Douglas A. Bennett , Shannon M. Duff , Michael R. Vissers , Joel N. Ullom

It has recently been shown that a subdominant hidden sector of atomic dark matter in the early universe provides a novel avenue towards resolving the Hubble ($H_0$) tension while maintaining good agreement with Cosmic Microwave Background…

高能物理 - 唯象学 · 物理学 2022-05-12 Nikita Blinov , Gordan Krnjaic , Shirley Weishi Li

We discuss the phenomenological imprints of modifications to gravity in the early universe with a specific focus on the time of recombination. We derive several interesting results regarding the effect that such modifications have on…

宇宙学与河外天体物理 · 物理学 2019-02-20 Meng-Xiang Lin , Marco Raveri , Wayne Hu

Induced emission due to the presence of soft CMB photons slightly increases the two-photon decay rate of the 2s level of hydrogen defining the rate of cosmological recombination. This correspondingly changes the degree of ionization, the…

天体物理学 · 物理学 2009-11-13 J. Chluba , R. A. Sunyaev

We examine cosmic microwave background constraints on variations in the recombination history of the universe. We use a very general extension to the standard model of recombination characterized by two parameters, a and b, which multiply…

天体物理学 · 物理学 2007-05-23 Angela M. Linn , Robert J. Scherrer

Several mechanisms have been proposed to generate primordial magnetic fields and it is often assumed that magnetic fields are not affected by a sharp drop in ionization rate due to the cosmic recombination. We investigate the validity of…

天体物理学 · 物理学 2008-04-23 Keitaro Takahashi