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arXiv · 2510.09602

Anchoring the Universe with Characteristic Redshifts using Raychaudhuri Equation Informed Reconstruction Algorithm (REIRA)

Shibendu Gupta Choudhury·Purba Mukherjee·Anjan Ananda Sen
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Abstract

We study the robustness and physical implications of a set of characteristic redshifts that capture key features of the late-time Universe. Using both model-independent reconstructions as well as different dark energy (DE) parameterizations, we show that these redshifts remain stable across cosmological models and reconstruction algorithm, making them reliable geometric anchors of the expansion history. Moreover, the Alcock-Paczy\'nski corrections at these redshift anchors are found to be unity with high statistical significance, making them natural isotropy points in the comoving distance-redshift relation. We also find that certain redshifts anchors $(z < 1)$ coincide with epochs where strong deviations from the Planck $\Lambda$CDM baseline are apparent irrespective of DE parametrisation like CPL or reconstruction algorithm, indicating their potential as probes of new physics in cosmological evolution. Finally, we demonstrate, for the first time, that a Raychaudhuri Equation Informed Reconstruction Algorithm, substantially enhances the precision of the inferred distance measures and the Hubble expansion rate as well as results tighter constraints in the DE parameter space. These results demonstrate that combining geometric reconstruction with physics-informed kinematic information offers a powerful and consistent algorithm to probe new physics in the late-time dynamics of our Universe.

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Shibendu Gupta Choudhury, Purba Mukherjee, Anjan Ananda Sen. 2025-10-10. Anchoring the Universe with Characteristic Redshifts using Raychaudhuri Equation Informed Reconstruction Algorithm (REIRA). https://arxiv.org/abs/2510.09602

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