English

Primordial Bounce-Inflation Scenario to Alleviate Cosmological Tensions and Lensing Anomaly

Cosmology and Nongalactic Astrophysics 2025-03-12 v2 General Relativity and Quantum Cosmology

Abstract

We put forward a primordial scenario to alleviate cosmological tensions, i.e. Hubble (H0H_0) tension and S8 S_8 tension. Based on flat Λ\LambdaCDM, the Bounce-Inflation (BI) scenario gives the results that H0=68.600.45+0.40km/s/Mpc H_0 = 68.60^{+0.40}_{-0.45} \, \text{km}/\text{s}/\text{Mpc}, S8=0.806±0.011 S_8 = 0.806 \pm 0.011 by using \texttt{Planck 2018} data sets and H0=68.96±0.38km/s/Mpc H_0 = 68.96 \pm 0.38 \, \text{km}/\text{s}/\text{Mpc}, S8=0.797±0.010 S_8 = 0.797\pm 0.010 by using \texttt{Planck 2018} + \texttt{SPT3G} data sets. These reduce the cosmological tensions slightly. We also take an extended Λ\LambdaCDM model into account, Λ\LambdaCDM (BI)+ALA_L, where AL A_L is the gravitational lensing amplitude. The results are H0=69.38±0.49km/s/Mpc H_0 = 69.38 \pm 0.49 \, \text{km}/\text{s}/\text{Mpc}, S8=0.774±0.014 S_8 = 0.774 \pm 0.014 fitted by \texttt{Planck 2018} data sets and H0=69.49±0.45km/s/Mpc H_0 = 69.49 \pm 0.45 \, \text{km}/\text{s}/\text{Mpc}, S8=0.7710.012+0.013 S_8 = 0.771^{+0.013}_{-0.012} fitted by \texttt{Planck 2018} + \texttt{SPT3G} data sets, which reduce the Hubble tension to 3σ\sim 3\sigma level and show no S8S_8 tension. The AL1.1A_L \approx 1.1 is smaller than the result of the inflation scenario with a constraint of \texttt{Planck 2018} data sets. Besides, the spectral index of the bounce-inflation scenario ns n_s is about 0.98 0.98 , with a trend to the Harrison-Zel'dovich spectrum.

Keywords

Cite

@article{arxiv.2409.04027,
  title  = {Primordial Bounce-Inflation Scenario to Alleviate Cosmological Tensions and Lensing Anomaly},
  author = {Hao-Hao Li and Xin-zhe Zhang and Taotao Qiu},
  journal= {arXiv preprint arXiv:2409.04027},
  year   = {2025}
}

Comments

3 pages, 2 figures, 1 table, science bulletin accepted