发表机构
University of Calcutta; Haldia Government College; Indian Institute of Science Education and Research, Kolkata; Prabhat Kumar College（加尔各答大学; 哈尔迪亚政府学院; 印度科学教育研究所加尔各答分校; 普拉巴特库马尔学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过双流体增长方程和多种宇宙学观测数据，证明耦合暗能量-暗物质模型可产生特征性的中微子质量标度及重组时暗物质质量变化，从而区分相互作用驱动的幻影穿越与纯运动学参数化。
AI 中文摘要
近期对宇宙膨胀的测量重新引起了人们对暗能量模型的兴趣，在这些模型中，有效状态方程表现出类似幻影的演化，并可能穿越$w=-1$。然而，这种行为并不需要基本的幻影场：在耦合暗能量-暗物质（CDEDM）模型中，正则标量场与冷暗物质之间的能量交换（发生在拉格朗日标记中）可以重现与唯象$w_0w_a$CDM模型相同的有效状态方程演化。我们表明，这种微观相互作用通过形成双流体系统在结构增长中留下独特的、可检验的特征，在该系统中只有冷暗物质感受到标量介导的第五力（以及相关的阻力项），而重子保持不耦合。当与中微子自由流结合时，这种设置产生特征性的耦合-中微子质量简并，其主导标度$\sum m_\nu \propto f_c^2 \alpha^2$可从双流体增长方程解析得出。利用DESI DR2 BAO、CMB距离信息、ACT DR6透镜、红移空间畸变和三个超新星汇编，我们发现对于指数势和逆幂律势都能恢复这一标度。我们进一步表明，增长响应的主要贡献来自耦合引起的背景演化修正，其中第五力增强增长，而阻力部分抵消了这种增强。最后，相互作用导致暗物质质量运行，使其在重组时改变$4.3\\\\%$--$5.5\\\\%$，因此CMB距离计算必须考虑演化的暗物质密度。这些相关的增长和重组效应为区分相互作用驱动的幻影穿越与纯运动学暗能量参数化提供了途径。
英文摘要
Recent measurements of cosmic expansion have renewed interest in dark-energy scenarios in which the effective equation of state exhibits phantom-like evolution and may cross $w=-1$. Such behavior, however, does not require a fundamental phantom field: in coupled dark-energy-dark-matter~(CDEDM) models, energy exchange between a canonical scalar field and cold dark matter, happens Lagrangian labels, can reproduce the same effective equation of state evolution as that of phenomenological $w_0w_a$CDM model. We show that this microscopic interaction leaves distinctive, testable signatures in structure growth by forming a two-fluid system in which only cold dark matter feels the scalar-mediated fifth force (and an associated drag term), while baryons remain uncoupled. When combined with neutrino-free streaming, this setup generates a characteristic coupling, neutrino-mass degeneracy, whose leading scaling $\sum m_ν\propto f_c^2 α^2$ follows analytically from the two-fluid growth equations. Using DESI DR2 BAO, CMB distance information, ACT DR6 lensing, redshift-space distortions, and three supernova compilations, we find that this scaling is recovered for both exponential and inverse-power-law potentials. We further show that the dominant contribution to the growth response arises from the coupling-induced modification of the background evolution, with the fifth force enhancing growth and the drag partially counteracting it. Finally, the interaction induces a running dark-matter mass, changing it at recombination by $4.3\%$--$5.5\%$, so CMB distance calculations must account for the evolving dark-matter density. These correlated growth and recombination effects provide a route to distinguish interaction-driven phantom crossing from purely kinematic dark-energy parametrizations.
Comments25 pages, 9 figures, 7 tables
