A grounded perspective on new early dark energy using ACT, SPT, and BICEP/Keck

Cruz, Juan S.; Niedermann, Florian; Sloth, Martin S.

doi:10.1088/1475-7516/2023/02/041

Cited by 19 publications

(39 citation statements)

References 144 publications

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“…This is balanced by increasing the spectral tilt n s and amplitude A s . As argued in [48], the correlation between f NEDE and n s (fourth panel) has far-reaching implications for inflationary model-building. Specifically, it makes simple models of inflation such as power-law inflation or the curvaton [49,50,51] viable again.…”

Section: 3mentioning

confidence: 84%

“…In Cold NEDE, the primary theoretical tasks involve linking the equation of state parameter w NEDE to the effective field theory parameters in the potential and explaining the hierarchy between the trigger scale m and the tunneling scale M ≫ m. While we believe the latter can be achieved within a multiaxion framework, the former might require more detailed numerical studies. On a phenomenological level, new CMB data, such as future ACT releases [87] and the CMB-S4 experiment [88], as well as additional LSS data from observations of galaxy abundances and clustering or spectroscopic galaxy surveys, such as the James Web Telescope [89] or Euclid [90], will help discriminate the model from its competitors and constrain its unique signatures (for first studies including groundbased CMB and full-shape matter power spectrum data see [28,91,48,27]).…”

Section: Discussionmentioning

confidence: 99%

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New early dark energy

2021

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New measurements of the expansion rate of the Universe have plunged the standard model of cosmology into a severe crisis. In this paper, we propose a simple resolution to the problem that relies on a first order phase transition in a dark sector in the early Universe, before recombination. This will lead to a short phase of a new early dark energy (NEDE) component and can explain the observations. We model the false vacuum decay of the NEDE scalar field as a sudden transition from a cosmological constant source to a decaying fluid with constant equation of state. The corresponding fluid perturbations are covariantly matched to the adiabatic fluctuations of a subdominant scalar field that triggers the phase transition. Fitting our model to measurements of the cosmic microwave background (CMB), baryonic acoustic oscillations (BAO, and supernovae (SNe) yields a significant improvement of the best fit compared with the standard cosmological model without NEDE. We find the mean value of the present Hubble parameter in the NEDE model to be H 0 ¼ 71.4 AE 1.0 km s −1 Mpc −1 (68% C.L.).

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Section: 3mentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

New early dark energy

2021

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“…[5] showed in their figure 2, a degeneracy between Ω K and w is expected to some extent, but their Planck+BAO result is in perfect agreement with w = −1. Along the similar line, there are similar studies which consider different dark energy scenarios which become prominent well after the recombination (see e.g., [11,45,[76][77][78][79][80][81][82][83]). We leave the impact of these other extended parameters on the spatial curvature for future work.…”

Section: Summary and Discussionmentioning

confidence: 81%

Constraining the spatial curvature with cosmic expansion history in a cosmological model with a non-standard sound horizon

Stevens

Khoraminezhad

Saito

2023

J. Cosmol. Astropart. Phys.

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Spatial curvature is one of the most fundamental parameters in our current concordance flat ΛCDM model of the Universe. The goal of this work is to investigate how the constraint on the spatial curvature is affected by an assumption on the sound horizon scale. The sound horizon is an essential quantity to use the standard ruler from the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAOs). As an example, we study the curvature constraint in an axion-like Early Dark Energy (EDE) model in light of recent cosmological datasets from Planck, the South Pole Telescope (SPT), and the Atacama Cosmology Telescope (ACT), as well as BAO data compiled in Sloan Digital Sky Survey Data Release 16. We find that, independent of the CMB datasets, the EDE model parameters are constrained only by the CMB power spectra as precisely and consistently as the flat case in previous work, even with the spatial curvature. We also demonstrate that combining CMB with BAO is extremely powerful to constrain the curvature parameter even with a reduction of the sound-horizon scale in an EDE model, resulting in Ω K = -0.0058± 0.0031 in the case of ACT+BAO after marginalizing over the parameters of the EDE model. This constraint is as competitive as the Planck+BAO result in a ΛCDM model, Ω K = -0.0001± 0.0018.

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“…(Schöneberg et al 2022;Abdalla et al 2022). These often change the Universe's growth and/or expansion history at late times (Pogosian et al 2022;Heisenberg et al 2022), or introduce new physics at early times such that (i) the physical size of the sound horizon 𝑟 𝑑 ≡ 𝑟 𝑠 (𝑧 𝑑 ) decreases with respect to ΛCDM (Poulin et al 2019;Niedermann & Sloth 2021a;Hill et al 2021;Cruz et al 2022), (ii) the redshift of recombination is shifted (Jedamzik & Pogosian 2020;Galli et al 2022;Franchino-Viñas & Mosquera 2021;Sekiguchi & Takahashi 2021) or (iii) new features are introduced in the primordial spectrum of fluctuations (Hazra et al 2022;Antony et al 2022). While appealing from the theoretical standpoint, very few of the proposed solutions are actually able to simultaneously address these tensions.…”

Section: Introductionmentioning

confidence: 99%

On the consistency of $Λ$CDM with CMB measurements in light of the latest Planck, ACT, and SPT data

Calderón¹,

Shafieloo²,

Hazra³

et al. 2023

Preprint

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Using Gaussian Processes we perform a thorough, non-parametric consistency test of the ΛCDM model when confronted with state-of-the-art TT, TE and EE measurements of the anisotropies in the Cosmic Microwave Background by Planck, ACT, and SPT collaborations. We find no statistically significant deviation from ΛCDM's best fit predictions when looking for signatures in the residuals. The results of SPT are in good agreement with the ΛCDM best fit predictions to Planck data, while the results of ACT are only marginally consistent. Interestingly, the slight disagreement between Planck/SPT and ACT is mainly visible in the residuals of the TT spectrum, the latter favoring a scale-invariant tilt 𝑛 𝑠 1, consistent with previous findings using parametric analyses. We also report some features in the EE measurements captured both by ACT and SPT which could be hinting towards a common physical origin, or unknown systematics in the data. Finally, we test the internal consistency of the Planck data alone by studying the high and low-ℓ ranges separately, finding no discrepancy between small and large angular scales. Apart from the mentioned mild inconsistencies in TT and EE, our results show the overall agreement between the various ground and space-based CMB experiments with the standard model of cosmology.

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A grounded perspective on new early dark energy using ACT, SPT, and BICEP/Keck

Cited by 19 publications

References 144 publications

New early dark energy

New early dark energy

Constraining the spatial curvature with cosmic expansion history in a cosmological model with a non-standard sound horizon

On the consistency of $Λ$CDM with CMB measurements in light of the latest Planck, ACT, and SPT data

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