度规-仿射框架中的相互作用宇宙学模型
Interacting fluid cosmologies from the metric-affine framework
- University of Peloponnese（伯罗奔尼撒大学）
- Scuola Superiore Meridionale（南方高等学院）
- Istituto Nazionale di Fisica Nucleare – Sezione di Napoli（意大利国家核物理研究所那不勒斯分部）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文从度规-仿射引力出发，提出宇宙学流体间无需显式耦合即可产生有效相互作用，推导修正连续性方程，并利用多种观测数据与ΛCDM对比，发现该框架表现略优，为暗能量演化提供几何起源的可行替代方案。
AI中文摘要：
度规-仿射引力提供了一个自然的几何框架，其中时空曲率、挠率和非度规性被视为独立的自由度，从而产生了超越广义相对论的新奇宇宙学动力学。这类理论的一个普遍结果是，即使在没有显式唯象耦合的情况下，宇宙学流体之间也会出现有效相互作用。有趣的是，上述情况发生的同时，粒子物理标准模型保持不变。在本工作中，我们研究了由度规-仿射引力产生的相互作用宇宙学模型，并分析了它们对宇宙背景演化的影响。我们推导了控制物质、辐射和暗能量组分的修正连续性方程，强调了暗区能量交换的几何起源。我们讨论了这些相互作用如何修改膨胀历史，并能有效模拟演化的暗能量行为。所得的宇宙学情景与来自Ia型超新星（Pantheon+）、宇宙计时器和重子声学振荡（DESI DR2）的最新观测数据进行了对比。此外，利用模型选择标准，如Akaike信息准则、贝叶斯信息准则和贝叶斯证据，我们将上述模型与标准ΛCDM模型进行了比较。我们发现，在所考虑的数据集下，所提出的框架表现略优于ΛCDM。我们的分析表明，度规-仿射诱导的相互作用构成了描述宇宙的一个可行且具有理论动机的替代方案。
英文摘要：
Metric-affine gravity provides a natural geometric framework in which spacetime curvature, torsion, and non-metricity are treated as independent degrees of freedom, leading to novel cosmological dynamics beyond General Relativity. A generic consequence of such theories is the emergence of effective interactions among the cosmological fluids, even in the absence of explicit phenomenological couplings. Interestingly, the above happens while the Standard Model of Particle physics remains unmodified. In this work, we investigate interacting cosmological models that arise from metric-affine gravity and analyze their implications for the background evolution of the Universe. We derive the modified continuity equations governing the matter, radiation, and dark-energy components, highlighting the geometric origin of energy exchange in the dark sector. We discuss how these interactions modify the expansion history and can effectively mimic evolving dark-energy behavior. The resulting cosmological scenarios are confronted with the most recent observational data from Type Ia Supernovae (Pantheon+), Cosmic Chronometers, and Baryon Acoustic Oscillations (DESI DR2). Moreover, using model selection criteria, e.g., Akaike Information Criterion, Bayesian Information Criterion and the Bayesian Evidence, we compare the aforementioned models against the standard $Λ$CDM model. We find that the proposed framework performs slightly better than $ΛCDM$, in the light of the data sets considered here. Our analysis demonstrates that metric-affine-induced interactions constitute a viable and theoretically motivated alternative for the description of the Universe.
