阻尼谐振子暗能量模型的观测约束
Observational constraints on a damped harmonic oscillator model of dark energy
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中文总结 AI 辅助
本研究利用CMB、DESI BAO及三种超新星数据约束阻尼谐振子暗能量模型，发现其仅在低红移偏离ΛCDM，并给出不同数据集的H_0和w_0约束值。
中文摘要 AI 辅助
我们利用完整的宇宙微波背景（CMB）似然函数，结合DESI BAO数据和三个不同的Ia型超新星汇编（Pantheon+、DES-Dovekie和Union3），对阻尼谐振子（DHO）暗能量状态方程进行了约束。该状态方程满足关于e折数目的二阶阻尼振荡方程，因此其频率f、阻尼率b和平衡值w_m完全决定了晚期动力学行为。该模型仅在低红移处表现出振荡行为，围绕平衡值w=-1，且不同超新星汇编呈现不同特征：DES-Dovekie和Union3对应欠阻尼解，而Pantheon+对应过阻尼解。在较高红移处，该模型与ΛCDM模型非常接近，仅在z<0.6时出现显著偏离，偏离幅度取决于超新星汇编。我们进一步确定了(f,b)参数空间中的一个区域，该区域对应低红移处状态方程的快速变化，在此区域内扰动方程变得数值刚性，无法用标准暗能量声速（即c_s^2=1）进行积分。我们表明，降低静止系声速可以消除这一障碍，同时观测量的变化在10^-3量级以内，因此我们将其视为数值处理手段而非模型的物理修正。该模型给出的哈勃常数H_0分别为：Pantheon+为67.53^{+1.22}_{-1.18} km/s/Mpc，DES-Dovekie为69.08^{+1.23}_{-1.16} km/s/Mpc，Union3为70.67^{+1.89}_{-1.87} km/s/Mpc。当前状态方程参数w_0分别被约束为：Pantheon+为-0.521^{+0.891}_{-0.414}，DES-Dovekie为-3.01^{+1.14}_{-1.21}，Union3为-3.16^{+1.11}_{-1.16}。
英文摘要
We constrain a damped harmonic oscillator (DHO) dark-energy equation of state using the full cosmic microwave background (CMB) likelihoods in combination with DESI BAO and three distinct Type Ia supernova compilations: Pantheon+, DES-Dovekie, and Union3. The equation of state obeys a second-order damped oscillator equation in number of $e$-folds, so that its frequency $f$, damping rate $b$, and equilibrium value $w_{\rm m}$ fully specify the late-time dynamics. The model exhibits oscillatory behavior only at low redshifts, around the equilibrium value $w=-1$, with distinct characteristics for the different supernova compilations: an underdamped solution for DES-Dovekie and Union3, and an overdamped solution for Pantheon+. At higher redshifts, the model closely mimics $Λ$CDM and deviates significantly only at $z<0.6$, with the magnitude of the deviation depending on the supernova compilation. We further identify a region of the $(f,b)$ parameter space, corresponding to rapid variation of the equation of state at low redshift, in which the perturbation equations become numerically stiff and cannot be integrated with a canonical dark-energy sound speed i.e., $c_s^2 =1$. We show that reducing the rest-frame sound speed removes this obstruction while leaving the observables unchanged at the $10^{-3}$ level, and therefore treat it as a numerical prescription rather than a physical modification of the model. The model yields $H_0 = 67.53^{+1.22}_{-1.18}$ km/s/Mpc for Pantheon+, $H_0 = 69.08^{+1.23}_{-1.16}$ km/s/Mpc for DES-Dovekie, and $H_0 = 70.67^{+1.89}_{-1.87}$ km/s/Mpc for Union3. The present-day equation-of-state parameter is constrained to $w_0 = -0.521^{+0.891}_{-0.414}$, $-3.01^{+1.14}_{-1.21}$, and $-3.16^{+1.11}_{-1.16}$ for Pantheon+, DES-Dovekie, and Union3, respectively.
发表机构
- Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology（浙江工业大学理论物理与宇宙学研究所）
- State Key Laboratory of Radio Astronomy and Technology, Xinjiang Astronomical Observatory, CAS（中国科学院新疆天文台射电天文与技术重点实验室）
- Department of Physics, Guangdong Technion – Israel Institute of Technology（广东以色列理工学院物理系）
- Centre for Space Research, North-West University（西北大学空间研究中心）
- Department of Physics and Electronics, Adekunle Ajasin University（阿德科莱·阿贾辛大学物理与电子系）
机构由 AI 辅助整理，请以论文原文为准。
