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Bibliographic Details
Main Authors: Wang, Yihao, Lin, Weikang
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2506.04333
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Table of Contents:
  • We present an assumption-minimized framework for testing late-time cosmological models using Uncalibrated Cosmic Standards (UCS), including standard rulers and standard candles, without relying on absolute calibrations. The method exploits a tight, model-insensitive correlation between the sound horizons at recombination and the drag epoch. By avoiding dependence on pre-recombination physics and the amplitude of the Cosmic Microwave Background (CMB) power spectra, the UCS framework reduces potential early-Universe biases while retaining much of the constraining power of full analyses. Applying UCS to the recent dynamical dark energy (DE) study that reported deviations from $Λ$CDM, we find the constraints shift systematically toward the $Λ$CDM case. If this shift is physical, it may result from the omission of some pre-recombination physical processes that influence the scale dependence of the CMB spectra. We also observe a mild tension between uncalibrated standard rulers and candles, which can be largely mitigated by introducing a redshift-dependent magnitude bias in the supernova (SNe Ia) data. Our results highlight the importance of isolating post-recombination observables for testing late-time models in the era of precision cosmology, positioning UCS analysis as a robust framework for upcoming galaxy surveys.