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In the original holographic dark energy (HDE) model, the dark energy density is proposed to be $\rho_{de} = 3c^2M^2_{pl}L^{-2}$, with $c$ is a dimensionless constant characterizing the properties of the HDE. In this work, we propose the…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-25 Zhenhui Zhang , Miao Li , Xiao-Dong Li , Shuang Wang , Wen-Shuai Zhang

New measurements of the expansion rate of the Universe have plunged the standard model of cosmology into a severe crisis. In this letter, we propose a simple resolution to the problem that relies on a first order phase transition in a dark…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-24 Florian Niedermann , Martin S. Sloth

We present a complete analysis of the observational constraints and cosmological implications of our Bound Dark Energy (BDE) model aimed to explain the late-time cosmic acceleration of the universe. BDE is derived from particle physics and…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-15 Erick Almaraz , Axel de la Macorra

Early dark energy (EDE) is an extension to the $\Lambda$CDM model, proposed to reduce the tension between the measurements of the Hubble constant $H_0$ from the cosmic microwave background (CMB) and from the local cosmic distance ladder.…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-12 João Rebouças , Jonathan Gordon , Diogo H. F. de Souza , Kunhao Zhong , Vivian Miranda , Rogerio Rosenfeld , Tim Eifler , Elisabeth Krause

Early dark energy (EDE) is a proposed solution to the Hubble tension in which a new cosmological field accelerates cosmic expansion prior to recombination and reduces the physical size of the sound horizon. In previous work, a slight…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-04 Adrien La Posta , Thibaut Louis , Xavier Garrido , J. Colin Hill

Recent interest in New Early Dark Energy (NEDE), a cosmological model with a vacuum energy component decaying in a triggered phase transition around recombination, has been sparked by its impact on the Hubble tension. Previous constraints…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-02 Juan S. Cruz , Steen Hannestad , Emil Brinch Holm , Florian Niedermann , Martin S. Sloth , Thomas Tram

It has been noted that with the pre-recombination early dark energy (EDE) resolution of Hubble tension, the preference of recent datasets for the evolving dark energy (DE) can be suppressed significantly. In this work, we clarify and…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-21 Hao Wang , Yun-Song Piao

This conference proceedings paper provides a short summary of the constraints presented by Menci et al. (2020) and Menci et al. (2022) to dynamical dark energy models. Dynamical dark energy (DDE) models have been proposed to address several…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Paola Santini , Nicola Menci , Marco Castellano

This work examines an early dark energy (EDE) scenario in the context of $F(R)$ gravity. EDE is introduced to alleviate the Hubble tension by temporarily injecting approximately $10\%$ of the energy fraction around the matter-radiation…

General Relativity and Quantum Cosmology · Physics 2026-04-21 Hua Chen , Taishi Katsuragawa , Shin'ichi Nojiri , Taotao Qiu

In this work we examine the possibility that the dark energy (DE) density, $\rho_{de}$ can be dynamical and appear as a power series expansion of the Hubble rate (and its derivatives), i.e.$\rho_{de}(H,\dot{H},...)$. For the present…

General Relativity and Quantum Cosmology · Physics 2019-07-30 Mehdi Rezaei , Mohammad Malekjani , Joan Sola

The early dark energy (EDE) extension to $\Lambda$CDM has been proposed as a candidate scenario to resolve the "Hubble tension". We present new constraints on the EDE model by incorporating new data from the Dark Energy Spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-26 Frank J. Qu , Kristen M. Surrao , Boris Bolliet , J. Colin Hill , Blake D. Sherwin , Hidde T. Jense

In this work, we investigate two Dark Energy (DE) models characterized by higher-order derivatives of the Hubble parameter $H$, which generalize previously proposed DE scenarios. Assuming a power-law form of the scale factor $a(t)$ given by…

General Relativity and Quantum Cosmology · Physics 2025-10-14 Antonio Pasqua

In this work, we study a class of early dark energy (EDE) models, in which, unlike in standard DE models, a substantial amount of DE exists in the matter-dominated era, self-consistently including DE perturbations. Our analysis shows that,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Ujjaini Alam

A promising idea to resolve the long standing Hubble tension is to postulate a new subdominant dark-energy-like component in the pre-recombination Universe which is traditionally termed as the Early Dark Energy (EDE). However, as shown in…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 Anton Chudaykin , Dmitry Gorbunov , Nikita Nedelko

We investigate the constraints on early dark energy (EDE) by combining the most recent CMB observations available, ACT DR4, SPT-3G, and Planck2018 ($\ell_\text{TT,max}=1000$) data. This combined CMB dataset favors non-zero EDE fractions and…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 Jun-Qian Jiang , Yun-Song Piao

Current cosmological data exhibit a tension between inferences of the Hubble constant, $H_0$, derived from early and late-universe measurements. One proposed solution is to introduce a new component in the early universe, which initially…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 J. Colin Hill , Evan McDonough , Michael W. Toomey , Stephon Alexander

The nature of dark matter remains one of the most fundamental and unresolved questions in modern cosmology. In most cosmological models, dark matter is typically modeled as pressureless dust with an equation of state (EoS) parameter $w_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-22 Tian-Nuo Li , Yi-Min Zhang , Yan-Hong Yao , Peng-Ju Wu , Jing-Fei Zhang , Xin Zhang

Axion-like early dark energy (EDE) as an extension to $\Lambda$CDM has been proposed as a possible solution to the 'Hubble tension'. We revisit this model using a new cosmic microwave background (CMB) temperature and polarization likelihood…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-02 George Efstathiou , Erik Rosenberg , Vivian Poulin

In the statistical framework of model-independent Gaussian processes (GP), we search for the evidence of dynamical dark energy (DDE) using the "Joint Light-curve Analysis" (JLA) Type Ia supernovae (SNe Ia) sample, the 30 latest cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-02 Deng Wang , Wei Zhang , Xin-He Meng

Early Dark Energy (EDE) contributing a fraction $f_{\rm EDE}(z_c)\sim 10 \%$ of the energy density of the universe around $z_c\simeq 3500$ and diluting as or faster than radiation afterwards, can provide a resolution to the Hubble tension,…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-04 Riccardo Murgia , Guillermo F. Abellán , Vivian Poulin