发表机构
SR University; Centre for Interdisciplinary Studies and Research, D Y Patil International University（SR大学; D Y Patil国际大学跨学科研究与教育中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出新型CPL型$Om(z)$参数化，结合多观测数据约束后发现其与$\Lambda$CDM统计上具有竞争力，倾向 quintessence 类暗能量，为晚期宇宙演化研究提供灵活框架。
AI 中文摘要
本研究提出一种CPL型$Om(z)$参数化形式：$Om(z)=l+m\left(\frac{z}{1+z}\right)$，用于研究暗能量的演化及其与标准$\Lambda$CDM宇宙学的可能偏差。当$m=0$时，该模型退化为平坦$\Lambda$CDM场景；$m\neq0$则表明存在动力学演化。通过马尔可夫链蒙特卡罗分析，利用Pantheon+SH0ES（PPS）、宇宙计时仪（CC）和DESI BAO DR2观测数据约束自由参数。所得约束给出$72.48\lesssim H_0\lesssim72.97\\,\mathrm{km\\,s^{-1}\\,Mpc^{-1}}$，且所有数据集组合下演化参数均为负，导致$Om(z)$演化递减，倾向于 quintessence 类行为。PPS+CC+DR2联合分析使演化更接近$\Lambda$CDM极限。基于$\chi^2$、AIC和BIC的统计分析表明，该模型在统计上与$\Lambda$CDM具有竞争力。进一步分析减速参数和总状态方程以研究宇宙演化，减速到加速的转变发生在$z_{tr}\approx0.66-1.01$范围内，当前值随数据集变化为$-0.459\lesssim q_0\lesssim-0.325$和$-0.639\lesssim\omega_0\lesssim-0.550$。总体而言，所提参数化为研究晚期宇宙演化提供了灵活框架。
英文摘要
In this work, we investigate a CPL-type $Om(z)$ parametrization given by $Om(z)=l+m\left(\frac{z}{1+z}\right)$ to study the evolution of dark energy and possible deviations from the standard $Λ$CDM cosmology. The model reduces to the flat $Λ$CDM scenario for $m=0$, while $m\neq0$ indicates dynamical evolution. The free parameters are constrained using Pantheon+SH0ES (PPS), Cosmic Chronometer (CC), and DESI BAO DR2 observations through Markov Chain Monte Carlo analysis. The obtained constraints yield $72.48\lesssim H_0\lesssim72.97~\mathrm{km\,s^{-1}\,Mpc^{-1}}$, while the evolution parameter remains negative for all dataset combinations, leading to decreasing $Om(z)$ evolution and favoring quintessence-like behaviour. The combined PPS+CC+DR2 analysis shifts the evolution closer to the $Λ$CDM limit. The statistical analysis based on $χ^2$, AIC, and BIC indicates that the proposed model remains statistically competitive with $Λ$CDM. The deceleration parameter and total equation of state are further analyzed to examine the cosmic evolution. The transition from deceleration to acceleration occurs within $z_{tr}\approx0.66-1.01$, while the present values vary within $-0.459\lesssim q_0\lesssim-0.325$ and $-0.639\lesssimω_0\lesssim-0.550$ depending on the datasets. Overall, the proposed parametrization provides a flexible framework for studying late-time cosmic evolution.
Comments14 pages, 6 figures, and 5 tables. Comments are welcome
