发表机构
Delhi Technological University（德里理工大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过微扰修正参数化冷暗物质稀释偏差，引入体粘度扩展相互作用暗区模型，利用多种观测数据约束参数，发现粘性效应影响晚期动力学但受早期信息抑制，且满足广义第二定律。
AI 中文摘要
我们研究了一个相互作用的暗区场景，其中冷暗物质标准稀释定律的偏差通过微扰修正$\epsilon$参数化，从而诱导出动力学真空分量。我们通过允许暗物质表现为具有体粘度的非完美流体来扩展这一框架。在Eckart形式中，我们考虑了体粘性系数对暗物质能量密度的幂律依赖，这为粘性压力产生了有效的密度标度。我们使用多嵌套采样方法\texttt{Dynesty}获得参数约束，采用了DES 5年Ia型超新星、DESI重子声学振荡、宇宙计时器、来自H0DN的局部$H_0$测量以及宇宙微波背景距离先验。还纳入了来自SDSS-IV的红移空间畸变测量和DES对$S_8$的弱引力透镜约束，以探测结构形成。我们还检验了宇宙学场景的热力学一致性，发现它们满足广义第二热力学定律。我们发现体粘性效应可以修改晚期相互作用动力学，而一旦包含早期宇宙信息，其贡献则被抑制。这些结果为偏离标准冷暗物质演化和恒定真空能提供了观测和热力学约束。
英文摘要
We investigate an interacting dark sector scenario in which a deviation from the standard dilution law of cold dark matter is parametrized by a perturbative correction $ε$, thereby inducing a dynamical vacuum component. We extend this framework by allowing dark matter to behave as an imperfect fluid with bulk viscosity. Within the Eckart formalism, we consider a power-law dependence of the bulk viscous coefficient on the dark matter energy density which yields an effective density scaling for the viscous pressure. We obtain the parameter constraints using multi-nested sampling with \texttt{Dynesty}, employing DES 5YR Type Ia Supernovae, DESI Baryon Acoustic Oscillations, Cosmic Chronometers, the local $H_0$ measurement from H0DN, and Cosmic Microwave Background distance priors. Redshift Space Distortion measurements from SDSS-IV and the DES weak-lensing constraint on $S_8$ are included to probe structure formation. We also examine the thermodynamic consistency of the cosmological scenarios and find that they satisfy the Generalized Second Law of thermodynamics. We find that bulk viscous effects can modify the late-time interaction dynamics, while their contribution is suppressed once early-Universe information is included. These results provide observational and thermodynamic constraints on departures from the standard cold dark matter evolution and a constant vacuum energy.
Comments32 pages, 10 figures
