[论文解读] The Hubble Tension and Early Dark Energy

Marc Kamionkowski, Adam G. Riess|arXiv (Cornell University)|Nov 8, 2022

Cosmology and Gravitation Theories被引用 23

一句话总结

本文综述了哈勃常数问题，主张当前数据倾向于早宇宙解——特别是早期暗能量（EDE）——并讨论如何用未来测量测试 EDE。

ABSTRACT

Over the past decade, the disparity between the value of the cosmic expansion rate directly determined from measurements of distance and redshift or instead from the standard $Λ$CDM cosmological model calibrated by measurements from the early Universe, has grown to a level of significance requiring a solution. Proposed systematic errors are not supported by the breadth of available data (and "unknown errors" untestable by lack of definition). Simple theoretical explanations for this "Hubble tension" that are consistent with the majority of the data have been surprisingly hard to come by, but in recent years, attention has focused increasingly on models that alter the early or pre-recombination physics of $Λ$CDM as the most feasible. Here, we describe the nature of this tension, emphasizing recent developments on the observational side. We then explain why early-Universe solutions are currently favored and the constraints that any such model must satisfy. We discuss one workable example, early dark energy, and describe how it can be tested with future measurements. Given an assortment of more extended recent reviews on specific aspects of the problem, the discussion is intended to be fairly general and understandable to a broad audience.

研究动机与目标

• Explain the nature and significance of the Hubble tension between local and early-Universe measurements.
• Assess why early-Universe solutions, particularly early dark energy, are favored given current data.
• Describe constraints on EDE models and outline how future observations can test them.

提出的方法

• Summarize observational measurements of H0 from local distance ladders, CMB, and other probes.
• Outline the theoretical landscape comparing early- and late-time solutions to the tension, with emphasis on EDE.
• Discuss concrete EDE model variants and their observational consequences.

实验结果

研究问题

• RQ1 What is the current status and significance of the Hubble tension between local and early-Universe probes?
• RQ2 Why are early-Universe (pre-recombination) solutions, and specifically early dark energy, considered viable explanations for the tension?
• RQ3 What constraints must any EDE model satisfy to remain consistent with CMB, LSS, and other data?
• RQ4 What observable signatures or tests could confirm or falsify EDE as a resolution to the Hubble tension?

主要发现

• The Hubble constant inferred from local measurements (e.g., SH0ES) is around 73 km/s/Mpc, higher than Planck CMB-based values within ΛCDM.
• Model-dependent local measurements (e.g., strong lensing, ages) largely agree with higher H0, reinforcing the tension.
• Early dark energy (EDE) is explored as a workable class of solutions that can reconcile CMB and local measurements by altering pre-recombination physics.
• CMB polarization data and small-scale observations increasingly constrain EDE, with future measurements expected to further test these models.
• The paper discusses several EDE realizations (oscillating-field, slow-roll, generalized EDE) and notes independent avenues (e.g., cosmic birefringence, nonlinear evolution) for testing EDE.
• Independent local distance indicators (SBF, TRGB, Miras, gravitational waves, masers) provide cross-checks on H0 and are crucial for validating the tension.