A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy
Abstract Hubble tension is a problem in one-dimensional (1D) posteriors, since local $$H_0$$ H 0 determinations are only sensitive to a single parameter. Projected 1D posteriors for $$\Lambda $$ Λ CDM cosmological parameters become more non-Gaussian with increasing effective redshift when the model...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2025-02-01
|
| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-024-13727-0 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832571378780340224 |
|---|---|
| author | Eoin Ó. Colgáin Saeed Pourojaghi M. M. Sheikh-Jabbari Darragh Sherwin |
| author_facet | Eoin Ó. Colgáin Saeed Pourojaghi M. M. Sheikh-Jabbari Darragh Sherwin |
| author_sort | Eoin Ó. Colgáin |
| collection | DOAJ |
| description | Abstract Hubble tension is a problem in one-dimensional (1D) posteriors, since local $$H_0$$ H 0 determinations are only sensitive to a single parameter. Projected 1D posteriors for $$\Lambda $$ Λ CDM cosmological parameters become more non-Gaussian with increasing effective redshift when the model is fitted to redshift-binned data in the late Universe. We explain mathematically why this non-Gaussianity arises and show, using observational Hubble data (OHD), that Markov chain Monte Carlo (MCMC) marginalisation leads to 1D posteriors that fail to track the $$\chi ^2$$ χ 2 minimum at $$68\%$$ 68 % confidence level in high redshift bins. To gain a second perspective, we resort to profile likelihoods as a complementary technique. Doing so, we observe that $$z \gtrsim 1$$ z ≳ 1 cosmic chronometer (CC) data currently prefer a non-evolving (constant) Hubble parameter over a Planck- $$\Lambda $$ Λ CDM cosmology at $$\sim 2 \sigma $$ ∼ 2 σ . Within the Hubble tension debate, it is imperative that subsamples of data sets with differing redshifts yield similar $$H_0$$ H 0 values. In addition, we confirm that MCMC degeneracies observed in 2D posteriors are not due to curves of constant $$\chi ^2$$ χ 2 . Finally, on the assumption that the Planck- $$\Lambda $$ Λ CDM cosmological model is correct, using profile likelihoods we confirm a $$>2 \sigma $$ > 2 σ discrepancy with Planck- $$\Lambda $$ Λ CDM in a combination of CC and baryon acoustic oscillations (BAO) data beyond $$z \sim 1.5$$ z ∼ 1.5 . This confirms a discrepancy reported earlier with fresh methodology. |
| format | Article |
| id | doaj-art-696296d1d14e4ec7aeb85750886097b4 |
| institution | Kabale University |
| issn | 1434-6052 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj-art-696296d1d14e4ec7aeb85750886097b42025-02-02T12:38:36ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522025-02-0185211710.1140/epjc/s10052-024-13727-0A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracyEoin Ó. Colgáin0Saeed Pourojaghi1M. M. Sheikh-Jabbari2Darragh Sherwin3Atlantic Technological UniversitySchool of Physics, Institute for Research in Fundamental Sciences (IPM)School of Physics, Institute for Research in Fundamental Sciences (IPM)Atlantic Technological UniversityAbstract Hubble tension is a problem in one-dimensional (1D) posteriors, since local $$H_0$$ H 0 determinations are only sensitive to a single parameter. Projected 1D posteriors for $$\Lambda $$ Λ CDM cosmological parameters become more non-Gaussian with increasing effective redshift when the model is fitted to redshift-binned data in the late Universe. We explain mathematically why this non-Gaussianity arises and show, using observational Hubble data (OHD), that Markov chain Monte Carlo (MCMC) marginalisation leads to 1D posteriors that fail to track the $$\chi ^2$$ χ 2 minimum at $$68\%$$ 68 % confidence level in high redshift bins. To gain a second perspective, we resort to profile likelihoods as a complementary technique. Doing so, we observe that $$z \gtrsim 1$$ z ≳ 1 cosmic chronometer (CC) data currently prefer a non-evolving (constant) Hubble parameter over a Planck- $$\Lambda $$ Λ CDM cosmology at $$\sim 2 \sigma $$ ∼ 2 σ . Within the Hubble tension debate, it is imperative that subsamples of data sets with differing redshifts yield similar $$H_0$$ H 0 values. In addition, we confirm that MCMC degeneracies observed in 2D posteriors are not due to curves of constant $$\chi ^2$$ χ 2 . Finally, on the assumption that the Planck- $$\Lambda $$ Λ CDM cosmological model is correct, using profile likelihoods we confirm a $$>2 \sigma $$ > 2 σ discrepancy with Planck- $$\Lambda $$ Λ CDM in a combination of CC and baryon acoustic oscillations (BAO) data beyond $$z \sim 1.5$$ z ∼ 1.5 . This confirms a discrepancy reported earlier with fresh methodology.https://doi.org/10.1140/epjc/s10052-024-13727-0 |
| spellingShingle | Eoin Ó. Colgáin Saeed Pourojaghi M. M. Sheikh-Jabbari Darragh Sherwin A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy European Physical Journal C: Particles and Fields |
| title | A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy |
| title_full | A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy |
| title_fullStr | A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy |
| title_full_unstemmed | A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy |
| title_short | A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy |
| title_sort | comparison of bayesian and frequentist confidence intervals in the presence of a late universe degeneracy |
| url | https://doi.org/10.1140/epjc/s10052-024-13727-0 |
| work_keys_str_mv | AT eoinocolgain acomparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT saeedpourojaghi acomparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT mmsheikhjabbari acomparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT darraghsherwin acomparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT eoinocolgain comparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT saeedpourojaghi comparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT mmsheikhjabbari comparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy AT darraghsherwin comparisonofbayesianandfrequentistconfidenceintervalsinthepresenceofalateuniversedegeneracy |