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Out-of-distribution (OOD) detection is essential to improve the reliability of machine learning models by detecting samples that do not belong to the training distribution. Detecting OOD samples effectively in certain tasks can pose a…

Computer Vision and Pattern Recognition · Computer Science 2023-11-02 Divyanshu Mishra , He Zhao , Pramit Saha , Aris T. Papageorghiou , J. Alison Noble

We investigate the universe's evolution within the framework of Rastall gravity, which is an extension of the standard $\Lambda$CDM model. Utilizing a linear parametrization of the Equation of State (EoS) in a…

General Relativity and Quantum Cosmology · Physics 2024-10-17 J. K. Singh , Akanksha Singh , Shaily , Sushant G. Ghosh , Sunil D. Maharaj

Direct measurements of Hubble parameters $H(z)$ are very useful for cosmological model parameters inference. Based on them, Sahni, Shafieloo and Starobinski introduced a two-point diagnostic $Omh^2(z_i, z_j)$ as an interesting tool for…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-24 Xiaogang Zheng , Marek Biesiada , Xuheng Ding , Shuo Cao , Sixuan Zhang , Zong-Hong Zhu

We re-examine the growth index of the concordance $\Lambda$ cosmology in the light of the latest 6dF and {\em WiggleZ} data. In particular, we investigate five different models for the growth index $\gamma$, by comparing their cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Spyros Basilakos

In the present investigation we use observational data of $ f \sigma_ {8} $ to determine observational constraints in the plane $(\Omega_{m0},\sigma_{8})$ using two different methods: the growth factor parametrization and the numerical…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 A. M. Velásquez-Toribio , Júlio C. Fabris

In this paper, we propose a new parametrization of $Om(z)$ diagnostics and show how the most recent and significantly improved observations concerning the $H(z)$ and SN Ia measurements can be used to probe the consistency or tension between…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-13 Jing-Zhao Qi , Shuo Cao , Marek Biesiada , Tengpeng Xu , Yan Wu , Sixuan Zhang , Zong-Hong Zhu

This manuscript presents a diagnostic analysis of three dark energy models resulting from the parametrization of the deceleration parameter. These models exhibit intriguing features, including late-time acceleration and a cosmological phase…

General Relativity and Quantum Cosmology · Physics 2024-08-12 Dhruv Arora , Himanshu Chaudhary , Shibesh Kumar Jas Pacif , G. Mustafa

Using 137,562 quasars in the redshift range $2.1\leq z\leq3.5$ from the Data Release 11 (DR11) of the Baryon Oscillation Spectroscopic Survey (BOSS) of Sloan Digital Sky Survey (SDSS)-III, the BOSS-SDSS collaboration estimated the expansion…

General Relativity and Quantum Cosmology · Physics 2015-12-02 Suresh Kumar

We apply the statefinder hierarchy plus the fractional growth parameter to explore the extended Ricci dark energy (ERDE) model, in which there are two independent coefficients $\alpha$ and $\beta$. By adjusting them, we plot evolution…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-06 Fei Yu , Jing-Lei Cui , Jing-Fei Zhang , Xin Zhang

We compare the cosmological kinematics obtained via our law of linearly varying deceleration parameter (LVDP) with the kinematics obtained in the {\Lambda}CDM model. We show that the LVDP model is almost indistinguishable from the…

General Relativity and Quantum Cosmology · Physics 2012-10-04 Ozgur Akarsu , Tekin Dereli

In this letter we propose two general models for paradigm shift, deterministic propagation model (DM) and stochastic propagation model (SM). By defining the order parameter $m$ based on the diversity of ideas, $\Delta$, we study when and…

Physics and Society · Physics 2015-06-12 Huiseung Chae , Soon-Hyung Yook , Yup Kim

Creation of Cold Dark Matter (CCDM) can macroscopically be described by a negative pressure, and, therefore, the mechanism is capable to accelerate the Universe, without the need of an additional dark energy component. In this framework we…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 J. F. Jesus , F. A. Oliveira , S. Basilakos , J. A. S. Lima

Concordance $\Lambda$CDM universe is the simplest model that is consistent with a large variety of cosmological observations till date. But few recent observations indicate inconsistencies in $\Lambda$CDM model. In this paper, we consider…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-14 Anto I. Lonappan , Ruchika , Anjan A Sen

Rapid progress in representation learning has led to a proliferation of embedding models, and to associated challenges of model selection and practical application. It is non-trivial to assess a model's generalizability to new, candidate…

Machine Learning · Computer Science 2022-02-18 Leo Betthauser , Urszula Chajewska , Maurice Diesendruck , Rohith Pesala

In this work, we carry out a comprehensive perturbative analysis of four cosmological models featuring a sign-switching cosmological constant. Among these, we include the well-known $\Lambda_{\rm s}$CDM model, characterised by an abrupt…

General Relativity and Quantum Cosmology · Physics 2025-10-13 Mariam Bouhmadi-López , Beñat Ibarra-Uriondo

We investigate a phenomenological extension of the standard $\Lambda$CDM framework, the $\Omega_1\Omega_2$-$\Lambda$CDM model, in which the total energy density of the universe is expanded in powers of $1+z$. This parameterization recovers…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-20 Suresh Kumar

One approach to reconciling local measurements of a high expansion rate with observations of acoustic oscillations in the CMB and galaxy clustering (the "Hubble tension") is to introduce additional contributions to the $\Lambda$CDM model…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Raphaël Kou , Antony Lewis

Several models based on General Relativity and Modified Gravity aim to reproduce the observed universe with precision comparable to the flat-$\Lambda$CDM cosmological model. In this study, we investigate the consistency of some of these…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-05 Fernanda Oliveira , Bruno Ribeiro , Wiliam S. Hipólito-Ricaldi , Felipe Avila , Armando Bernui

$Om$ diagnostic can differentiate between different models of dark energy without the accurate current value of matter density. We apply this geometric diagnostic to dilaton dark energy(DDE) model and differentiate DDE model from LCDM. We…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-17 Z. G. Huang , H. Q. Lu

We perform the two$-$point diagnostic for the $Om(z)$ function proposed by Sahni ${\it et al}$ in 2014 for the Starobinsky and Hu & Sawicki models in $f(R)$ gravity. We show that the observed values of the $Omh^2$ function can be explained…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Luisa G. Jaime