Yano-Schrödinger Hyperfluid: Cosmological Implications

Fuente: arXiv
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Main Authors: Chaudhary, Himanshu, Hussain, Saddam
Format: Preprint
Published: 2025
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author Chaudhary, Himanshu
Hussain, Saddam
author_facet Chaudhary, Himanshu
Hussain, Saddam
contents Perfect cosmological hyperfluids generalize the concept of a perfect fluid within the framework of metric affine gravity. These hyperfluids encode the microstructure of matter including shear, dilation, and spin via the hypermomentum tensor. In this paper, we focus on the observational constraints of the recently introduced Yano-Schrödinger hyperfluid, which sources a special type of nonmetricity, that preserves the lengths of vectors under autoparallel transport. We propose a model in which the effective nonmetricity contributions to pressure and matter density are related linearly as $p_{\text{eff}} = ωρ_{\text{eff}}$. This assumption allows for a straightforward parameterization of deviations from standard cosmological behavior while maintaining analytical tractability. To constrain the effective equation of state parameter $ω$, we perform a Bayesian parameter estimation using Nested Sampling, implemented via the \texttt{PyPolyChord} library. We use Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2), along with Type Ia supernova and Cosmic Chronometer data. In our analysis, we treat $r_d$ as a free parameter, enabling late-time data to extract posterior distributions for the Hubble constant ($ H_0$) and the sound horizon ($r_d$), along with the corresponding model parameters. Our results yield $H_0 = 67.4 \pm 4.0 km s ^{-1} Mpc ^{-1}$ and $r_d = 148.8 \pm 7.4$ Mpc, with $ω= -0.488$ . Finally, we use the logarithm of the Bayes factor to compare different Yano-Schrödinger model against the $Λ$CDM model. We find that the LESC model provides a better fit to the data, suggesting that modifications to metric-affine gravity could offer viable alternatives to the standard cosmological paradigm.
format Preprint
id arxiv_https___arxiv_org_abs_2503_23115
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Yano-Schrödinger Hyperfluid: Cosmological Implications
Chaudhary, Himanshu
Hussain, Saddam
General Relativity and Quantum Cosmology
Perfect cosmological hyperfluids generalize the concept of a perfect fluid within the framework of metric affine gravity. These hyperfluids encode the microstructure of matter including shear, dilation, and spin via the hypermomentum tensor. In this paper, we focus on the observational constraints of the recently introduced Yano-Schrödinger hyperfluid, which sources a special type of nonmetricity, that preserves the lengths of vectors under autoparallel transport. We propose a model in which the effective nonmetricity contributions to pressure and matter density are related linearly as $p_{\text{eff}} = ωρ_{\text{eff}}$. This assumption allows for a straightforward parameterization of deviations from standard cosmological behavior while maintaining analytical tractability. To constrain the effective equation of state parameter $ω$, we perform a Bayesian parameter estimation using Nested Sampling, implemented via the \texttt{PyPolyChord} library. We use Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2), along with Type Ia supernova and Cosmic Chronometer data. In our analysis, we treat $r_d$ as a free parameter, enabling late-time data to extract posterior distributions for the Hubble constant ($ H_0$) and the sound horizon ($r_d$), along with the corresponding model parameters. Our results yield $H_0 = 67.4 \pm 4.0 km s ^{-1} Mpc ^{-1}$ and $r_d = 148.8 \pm 7.4$ Mpc, with $ω= -0.488$ . Finally, we use the logarithm of the Bayes factor to compare different Yano-Schrödinger model against the $Λ$CDM model. We find that the LESC model provides a better fit to the data, suggesting that modifications to metric-affine gravity could offer viable alternatives to the standard cosmological paradigm.
title Yano-Schrödinger Hyperfluid: Cosmological Implications
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2503.23115