A generalized mass-to-horizon entropy has recently been proposed as an extension of the Bekenstein-Hawking area law, derived from a modified mass-horizon relation constructed to ensure consistency with the Clausius equation. Within the gravity-thermodynamics conjecture, this entropy formulation yields modified Friedmann equations, which recover the standard <math altimg='si45.svg'><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle></math>CDM cosmology in the appropriate limit of the model&#8217;s two free parameters. In the present study, we constrain this framework using observations from Type Ia supernovae (SNIa), cosmic chronometers (CC) and baryon acoustic oscillations (BAO), including the Second Data Release of the Dark Energy Spectroscopic Instrument (DESI DR2) survey, together with the Supernovae <math altimg='si46.svg'><msub><mi>H</mi><mn>0</mn></msub></math> for the Equation of State (SH0ES) distance&#8211;ladder prior, across four combinations of data sets. Although the extended entropic scenario yields a slightly better, or statistically comparable, fit to the data, model selection via the Akaike Information Criterion (AIC) mildly favors the cosmological constant as the dark energy candidate. Moreover, the <math altimg='si45.svg'><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle></math>CDM limit lies within <math altimg='si47.svg'><mrow><mo>&#8764;</mo><mspace width='-0.16em' /><mn>1</mn><mi>&#963;</mi></mrow></math> of our constraints, indicating no significant deviation from standard cosmology with current data.

Spain

Giuseppe Gaetano Luciano

South Africa

Chile

Andronikos Paliathanasis

Modified cosmology through generalized mass-to-horizon entropy: Observational constraints from DESI DR2 BAO data

This paper investigates the late-time cosmic dynamics using the matter-geometry coupled <math altimg='si6.svg'><mrow><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math> gravity model, where <math altimg='si82.svg'><mi>Q</mi></math> is the non-metricity scalar and <math altimg='si83.svg'><mi>T</mi></math> represents the trace of the energy-momentum tensor. We consider the paradigm power law <math altimg='si6.svg'><mrow><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math>-gravity model, <math altimg='si6.svg'><mrow><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math> = - <math altimg='si84.svg'><mrow><mi>&#945;</mi><mi>Q</mi><mo linebreak='goodbreak'>&#8722;</mo><mi>&#946;</mi><msup><mi>T</mi><mn>2</mn></msup><mo linebreak='goodbreak'>/</mo><msubsup><mi>H</mi><mn>0</mn><mn>2</mn></msubsup><mo linebreak='goodbreak'>+</mo><msub><mi>&#951;</mi><mn>0</mn></msub></mrow></math> (where <math altimg='si8.svg'><mi>&#945;</mi></math>, <math altimg='si9.svg'><mi>&#946;</mi></math> and <math altimg='si85.svg'><msub><mi>&#951;</mi><mn>0</mn></msub></math> are constants) to calculate the best-fit values of cosmological parameters <math altimg='si7.svg'><msub><mstyle mathvariant='normal'><mi>&#937;</mi></mstyle><mi>m</mi></msub></math>, <math altimg='si3.svg'><msub><mi>H</mi><mn>0</mn></msub></math>, <math altimg='si8.svg'><mi>&#945;</mi></math>, <math altimg='si9.svg'><mi>&#946;</mi></math>, <math altimg='si15.svg'><msub><mi>r</mi><mi>d</mi></msub></math> and <math altimg='si16.svg'><mi>M</mi></math> through the Monte Carlo Markov Chain (MCMC) simulations using cosmic chronometers (CC) baryon acoustic oscillation (BAO) taken from Dark Energy Spectroscopy Instrument (DESI) and the SNIa distance moduli measurements from the Pantheon + SH0ES, which consists of 1701 light curves of 1550 distinct supernovae. Some key cosmological parameters: the deceleration parameter <math altimg='si4.svg'><mrow><mi>q</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></math>, effective equation of state parameters <math altimg='si86.svg'><mrow><msub><mi>w</mi><mrow><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math>, Hubble parameter <math altimg='si10.svg'><mrow><mi>H</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></math>, and distance modulus <math altimg='si87.svg'><mrow><mi>&#956;</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></math> are presented. These dynamical quantities show that the <math altimg='si6.svg'><mrow><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math>-gravity model is compatible with transitioning towards a quintessence-like phase in the late-time. In conformity with <math altimg='si5.svg'><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle></math>CDM, we moreover take into account the geometrical interpretations by considering the state-finder parameters <math altimg='si11.svg'><mrow><mi>r</mi><mo linebreak='goodbreak'>&#8722;</mo><mi>s</mi></mrow></math> and <math altimg='si12.svg'><mrow><mi>r</mi><mo linebreak='goodbreak'>&#8722;</mo><mi>q</mi></mrow></math>, which are crucial parameters for additional analysis. Additionally, the statistical analysis has been carried out for further investigation of the viability <math altimg='si6.svg'><mrow><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math>-gravity model.

Shambel Sahlu

India

B.K. Shukla

R.K. Tiwari

Türkiye

Değer Sofuoğlu

Saudi Arabia

Alnadhief H A Alfedeel

Quintessence phase of the universe in <math altimg='si6.svg'><mrow><mi>f</mi><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math>-gravity with <italic>DESI DR2 BAO</italic> and <italic>Pantheon + SH0ES</italic> samples

In this study, we investigate the viability of the <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math> gravity framework in explaining the accelerated expansion of the universe within the context of the locally rotationally symmetric (LRS) Bianchi-I space-time. Modified gravity theories have emerged as promising alternatives to General Relativity (GR) to account for cosmic acceleration and dark energy phenomena. We employ observational constraints from Type Ia Supernovae (SN Ia), Baryon Acoustic Oscillations (BAO), and Cosmic Chronometers (CC) to calibrate the free parameters of our model. The field equations are formulated based on a specific functional form of <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math>, and analytical solutions are obtained. The Hubble parameter, deceleration parameter ( <math altimg='si10.svg'><mi>q</mi></math>), statefinder diagnostics <math altimg='si74.svg'><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>s</mi><mo>)</mo></mrow></math>, and the jerk parameter ( <math altimg='si12.svg'><mi>j</mi></math>) are utilized to analyze the evolutionary dynamics of the universe. Our results indicate a transition from a decelerating to an accelerating phase, with the transition redshift <math altimg='si75.svg'><mrow><msub><mi>z</mi><mi>t</mi></msub><mo linebreak='goodbreak'>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>7293</mn><mrow><mo>&#8722;</mo><mn>0.06</mn></mrow><mrow><mo>+</mo><mn>0.07</mn></mrow></msubsup></mrow></math> and present deceleration parameter <math altimg='si76.svg'><mrow><msub><mi>q</mi><mn>0</mn></msub><mo linebreak='goodbreak'>=</mo><mo>&#8722;</mo><mn>0.56</mn></mrow></math>, consistent with observational data. The estimated age of the universe in this framework is <math altimg='si77.svg'><mrow><mn>13.27</mn><mo>&#177;</mo><mn>0.26</mn></mrow></math> Gyrs. The statefinder parameters suggest that the model closely mimics the standard <math altimg='si5.svg'><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle></math>CDM scenario at present but exhibits deviations at earlier epochs, potentially indicating a dynamic nature of dark energy. The <math altimg='si78.svg'><msub><mi>O</mi><mi>m</mi></msub></math> diagnostic further confirms the compatibility of our model with a phantom-like behavior of dark energy. These findings support the viability of <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math> gravity as an alternative framework for explaining cosmic acceleration, providing new interplay between matter and curvature in gravitational dynamics.

Vinod Kumar Bhardwaj

Anil Kumar Yadav

S.H. Shekh

Constraining <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math> gravity with SN Ia and BAO observational data in Bianchi I space time

In this study, we explore the impact of various combinations of CMB-independent datasets, including the recent DESI BAO measurements, on the equation of state (EoS) of dark energy and other cosmological parameters within the framework of the dynamical dark energy model ($\textit{w}$CDM). Assuming a constant EoS parameter for dark energy, we derive constraints on the free parameters of the model using observational datasets such as DESI BAO, BBN, Observational Hubble Data (OHD), and Pantheon Plus (SN $$^+$$ ) and SH0ES. Our analysis examines the deviations of the $\textit{w}$CDM model from the standard $$\Lambda $$ CDM scenario and assesses its implications for cosmological tensions, particularly the $$H_0$$ tension [ $$\text {km}~\text {s}^{-1}~\text {Mpc}^{-1}$$ ]. We find that the combination of DESI BAO + BBN + OHD + SN $$^+$$ (DESI BAO + BBN + OHD + SN $$^+$$ and SH0ES) datasets provides constraints on $$w_{{\textrm{de}}0},$$ suggesting a possible deviation from the cosmological constant scenario at a significance level of $$1.6\sigma $$ $$(1.4\sigma ),$$ respectively. Furthermore, we observe an inverse correlation between $$w_{\text {de0}}$$ and $$H_0,$$ which highlights the role of dark energy dynamics in resolving the tension $$H_0$$ by approximately $$2.1\sigma (0.8\sigma )$$ from DESI BAO + BBN + OHD (DESI BAO + BBN + OHD + SN $$^+$$ and SH0ES) datasets, respectively. Our findings offer valuable insights into the nature of dark energy and its influence on the cosmic expansion history, with implications for future observational efforts. We utilize the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) to evaluate our model’s performance. The results indicate that the $\textit{w}$CDM model demonstrates superior effectiveness.

Manish Yadav

Archana Dixit

M. Barak

Anirudh Pradhan

Investigating the $\textit{w}$CDM model with latest DESI BAO observations

We revisit the evolution of cosmic acceleration in a spatially flat $$w_0w_a$$ CDM universe, in which the equation of state of dark energy takes the CPL parametrization, using the latest baryon acoustic oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument (DESI), in combination with Planck cosmic microwave background (CMB) data and several type Ia supernova datasets, including PantheonPlus, Union3, and DESY5. We analyze the deceleration parameter $\textit{q}$($\textit{z}$) and the jerk parameter $\textit{j}$($\textit{z}$) and further validate our results using the $\textit{Om}$($\textit{z}$) diagnostic. Our findings indicate significant deviations from the predictions of the $$\Lambda $$ CDM model. Specifically, DESI BAO, DESI BAO + CMB, DESI BAO + CMB + Union3, and DESI BAO + CMB + DESY5 all provide strong evidence for a slowing down of cosmic acceleration at late times, as indicated by $$j(0) < 0$$ at more than 1 $$\sigma $$ confidence level, within the framework of $$w_0w_a$$ CDM model. These results suggest that in the $$w_0w_a$$ CDM universe cosmic acceleration has already peaked and is now in a phase of decline.

China

Jincheng Wang

Hongwei Yu

Puxun Wu

Revisiting cosmic acceleration with DESI BAO

Recently, DESI has released baryon acoustic oscillation (BAO) data, and DES has also published its 5-year supernova (SN) data. These observations, combined with cosmic microwave background (CMB) data, support a dynamically evolving dark energy at a high confidence level. When using cosmological observations to weigh neutrinos, the results will be significantly affected by the measurement of dark energy due to the degeneracy between neutrino mass and the dark-energy equation of state. Therefore, we need to understand how the dynamical evolution of dark energy in the current situation will affect the measurement of neutrino mass. In this work, we utilize these latest observations and other additional distance measurements to discuss the mutual influence between neutrinos and dark energy, then calculate the Bayes factor to compare models. We consider three neutrino mass hierarchies, namely degenerate hierarchy (DH), normal hierarchy (NH), and inverted hierarchy (IH), as well as three dark energy models including $$\Lambda {\textrm{CDM}},$$ $$w{\textrm{CDM}},$$ and $$w_0w_a {\textrm{CDM}}$$ models. We find that cosmological data combined with the prior of particle physics experiments can provide strong to decisive evidence favoring the $$w_0w_a {{\textrm{CDM}}}+\sum m_\nu $$ model with NH. In the $$w_0w_a {\textrm{CDM}}$$ model, using the CMB+DESI+DESY5 data, we obtain constraints on the total neutrino mass, $$\sum m_\nu <0.171~{\textrm{eV}},\ 0.204~{\textrm{eV}},\ 0.220~{\textrm{eV}},$$ for DH, NH, and IH, respectively. Furthermore, taking into account the neutrino hierarchy or incorporating additional distance measurements results in a more pronounced deviation from the $$\Lambda $$ CDM model for dark energy. The latter, in particular, exhibits a deviation at a confidence level that surpasses $$4\sigma .$$

Guo-Hong Du

Peng-Ju Wu

Tian-Nuo Li

Xin Zhang

Impacts of dark energy on weighing neutrinos after DESI BAO

In this work, we propose to utilize the observed ratio of spherically-averaged distance to the sound horizon scale from Baryon Acoustic Oscillation (BAO) data to test the cosmic distance duality relation (CDDR) by comparing the luminosity distances (LDs) obtained from Type Ia supernovae (SNIa) observations with angular diameter distances (ADDs) derived from these ratio measurements, using a cosmological-model-independent method. To match the LDs with the ADDs at the identical redshifts, we employ two methods: a compressed form of the Pantheon sample and a hybrid approach that combines the binning method with an artificial neural network (ANN). The Hubble parameter ( ) at any redshift is reconstructed from the observed Hubble parameter data with the ANN to derive the ADD. To avoid potential biases resulted from the specific prior values of the absolute magnitude $$M_{\textrm{B}}$$ of SNIa and the sound horizon scale $$r_{\textrm{d}}$$ from BAO measurements, we introduce the fiducial parameter $$\kappa \equiv 10^{M_{\textrm{B}} \over 5}\, r_{\textrm{d}}^{3 \over 2} $$ and marginalize their impacts by treating them as nuisance parameters with flat prior distributions in our statistical analysis. Subsequently, we update the measurements of ratio of the transverse comoving distance to the sound horizon scale from the latest BAO data released by the Dark Energy Spectroscopic Instrument (DESI) collaboration for CDDR testing. Our results indicate that BAO observation provides a powerful tool for testing the CDDR, independent of both the absolute magnitude $$M_{\textrm{B}}$$ and sound horizon scale $$r_{\textrm{d}}$$ , as well as any cosmological model.

Fan Yang

Xiangyun Fu

Bing Xu

Kaituo Zhang

Yang Huang

Ying Yang

Testing the cosmic distance duality relation using Type Ia supernovae and BAO observations

Several studies in the literature have found a disagreement between compressed data on Baryon Acoustic Oscillations (BAO) derived using two distinct methodologies: the two-dimensional (2D, transverse or angular) BAO, which extracts the BAO signal from the analysis of the angular two-point correlation function; and the three-dimensional (3D or anisotropic) BAO, which also exploits the radial clustering signal imprinted on the large-scale structure of the universe. This discrepancy is worrisome, since many of the points contained in these data sets are obtained from the same parent catalogs of tracers and, therefore, we would expect them to be consistent. Since BAO measurements play a pivotal role in the building of the inverse distance ladder, this mismatch impacts the discourse on the Hubble tension and the study of theoretical solutions to the latter. So far, the discrepancy between 2D and 3D BAO has been only pointed out in the context of fitting analyses of cosmological models or parametrizations that, in practice, involve the choice of a concrete calibration of the comoving sound horizon at the baryon-drag epoch. In this Letter, for the first time, we quantify the tension in a much cleaner way, with the aid of apparent magnitudes of supernovae of Type Ia (SNIa) and excluding the radial component of the 3D BAO. We avoid the use of any calibration and cosmological model in the process. At this point we assume that the Etherington (a.k.a distance duality) relation holds. We use state-of-the-art measurements in our analysis, and study how the results change when the angular components of the 3D BAO data from BOSS/eBOSS are substituted by the recent data from DESI Y1. We find the tension to exist at the level of <math><mo>∼</mo><mn>2</mn><mi>σ</mi></math> and <math><mo>∼</mo><mn>2.5</mn><mi>σ</mi></math>, respectively, when the SNIa of the Pantheon+ compilation are used, and at <math><mo>∼</mo><mn>4.6</mn><mi>σ</mi></math> when the latter are replaced with those of DES Y5. In view of these results, we then apply a calibrator-independent method to investigate the robustness of the distance duality relation when analyzed not only with 3D BAO measurements, but also with 2D BAO. This is a test of fundamental physics, which covers, among other aspects, variations of the speed of light with the cosmic expansion or possible interactions between the dark and electromagnetic sectors. We do not find any significant hint for a violation of the cosmic distance duality relation in any of the considered data sets.

Italy

Arianna Favale

Adrià Gómez-Valent

Marina Migliaccio

Quantification of 2D vs 3D BAO tension using SNIa as a redshift interpolator and test of the Etherington relation

In this work, we test the cosmic distance duality relation (CDDR) by comparing the angular diameter distance (ADD) derived from the transverse Baryon Acoustic Oscillations (BAO) data with the luminosity distance (LD) from the Pantheon type Ia supernova (SNIa) sample. The binning method and Gaussian process are employed to match ADD data with LD data at the same redshift. First, we use nonparametric and parametric methods to investigate the impact of the specific prior values of the absolute magnitude  $$M_\textrm{B}$$  <math> <msub> <mi>M</mi> <mtext>B</mtext> </msub> </math>   from SNIa observations and the sound horizon scale  $$r_\textrm{s}$$  <math> <msub> <mi>r</mi> <mtext>s</mtext> </msub> </math>   from transverse BAO measurements on the CDDR tests. The results obtained from the parametric and non-parametric methods indicate that specific prior values of  $$M_\textrm{B}$$  <math> <msub> <mi>M</mi> <mtext>B</mtext> </msub> </math>   and  $$r_\textrm{s}$$  <math> <msub> <mi>r</mi> <mtext>s</mtext> </msub> </math>   lead to significant biases on the CDDR test. Then, to avoid these biases, we propose a method independent of  $$M_\textrm{B}$$  <math> <msub> <mi>M</mi> <mtext>B</mtext> </msub> </math>   and  $$r_\textrm{s}$$  <math> <msub> <mi>r</mi> <mtext>s</mtext> </msub> </math>   to test CDDR by considering the fiducial value of  $$\kappa \equiv 10^{M_\textrm{B} \over 5}r_\textrm{s}$$  <math> <mrow> <mi>κ</mi> <mo>≡</mo> <msup> <mn>10</mn> <mfrac> <msub> <mi>M</mi> <mtext>B</mtext> </msub> <mn>5</mn> </mfrac> </msup> <msub> <mi>r</mi> <mtext>s</mtext> </msub> </mrow> </math>   as a nuisance parameter and then marginalizing its influence with a flat prior in the analysis. No violation of the CDDR is found, and the transverse BAO measurement can be used as a powerful tool to verify the validity of CDDR in the cosmological-model-independent method.

Min Wang

Zhenyan Lu

Testing the cosmic distance duality relation with Type Ia supernova and transverse BAO measurements

The recent local measurements of the Hubble constant <math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math>, indicate a significant discrepancy of over 5σ compared to the value inferred from Planck observations of the cosmic microwave background (CMB). In this paper, we try to test the standard cosmological model ΛCDM by testing the consistency of early and late cosmological parameters in the same observed data. In practice, we simultaneously derive the early and late parameters using baryon acoustic oscillation (BAO) measurements, which provide both low and high-redshift information. CMB data are also included in the analysis as a “distance prior”, which tracks the same BAO feature and resolve parameter degeneracy. By using the parameter <math><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>=</mo><msub><mrow><mi>Ω</mi></mrow><mrow><mi>m</mi></mrow></msub><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn></mrow></msup></math>, we introduce <math><mrow><mi>ratio</mi></mrow><mo>(</mo><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>)</mo></math>, defined as the ratio of <math><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub></math> which are constrained from high and low-redshift measurements respectively, to quantify the consistency between early and late parameters. We obtained a value of <math><mrow><mi>ratio</mi></mrow><mo>(</mo><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>)</mo><mo>=</mo><mn>1.0069</mn><mo>±</mo><mn>0.0070</mn></math>, indicating there is no tension between early parameters and late parameters in the framework of ΛCDM model. As a result, our test does not expose the defects of the ΛCDM model. In addition, we forecast the future BAO measurements of <math><mrow><mi>ratio</mi></mrow><mo>(</mo><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>)</mo></math>, using several galaxy redshift surveys and 21 cm intensity mapping surveys, and find that these measurements can significantly improve the precision of cosmological parameters.

Guanlin Liu

Yu Wang

Wen Zhao

Testing the consistency of early and late cosmological parameters with BAO and CMB data