标量-矢量-张量暗能量穿越幻影分界的观测约束
Observational constraints on scalar-vector-tensor dark energy with phantom-divide crossing
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中文总结 AI 辅助
本研究通过DES、DESI及RSD数据约束SVT暗能量模型，发现其能稳定穿越幻影分界，且优于ΛCDM模型，贝叶斯因子大于1。
中文摘要 AI 辅助
我们约束了一个标量-矢量-张量（SVT）暗能量模型，其中矢量扇区在较早时期驱动暗能量状态方程降至-1以下，而随后一个正则标量场驱动其穿越-1，达到当前高于-1的值。我们将该模型与DES第五年超新星、DESI DR2重子声学振荡以及压缩的宇宙微波背景信息进行对比，并纳入Gold-2017红移空间畸变（RSD）测量以探测结构增长。背景后验赋予了穿越历史显著权重，并给出了比平坦Λ冷暗物质（ΛCDM）模型更好的最佳拟合。RSD分析保留了这种定性的背景演化，约束了聚集振幅，并增加了对方向性穿越准则的后验支持。由于增长分析还施加了额外的微扰支持条件，这种增加不能仅归因于RSD似然。匹配的PolyChord计算在两种先验体积约定下均给出SVT相对于ΛCDM的贝叶斯因子大于1。定量贝叶斯因子取决于对正则辐射时代分支的先验归一化，并且在任一约定下，RSD分析中的贝叶斯因子更大。总体而言，当前的膨胀和结构增长数据与SVT模型中幻影分界的稳定动力学穿越一致。
英文摘要
We constrain a scalar-vector-tensor (SVT) dark-energy model in which the vector sector drives the dark-energy equation of state below $-1$ at earlier times, while a canonical scalar field subsequently drives it across $-1$ toward a present-day value above $-1$. We confront the model with DES Year 5 supernovae, DESI DR2 baryon acoustic oscillations, and compressed cosmic microwave background information, and then include Gold-2017 redshift-space-distortion (RSD) measurements to probe structure growth. The background posterior assigns substantial weight to crossing histories and gives a better best fit than the flat $Λ$-cold-dark-matter ($Λ$CDM) model. The RSD analysis preserves this qualitative background evolution, constrains the clustering amplitude, and increases the posterior support for the directional crossing criterion. Since the growth analysis also imposes additional perturbative support conditions, this increase cannot be attributed to the RSD likelihood alone. Matched PolyChord calculations give Bayes factors larger than unity for SVT relative to $Λ$CDM under both prior-volume conventions considered here. The quantitative Bayes factor depends on the prior normalization assigned to the regular radiation-era branch and is larger in the RSD analysis under either convention. Overall, current expansion and structure-growth data are consistent with a stable dynamical crossing of the phantom divide in the SVT model.
发表机构
- Mahidol University（玛希隆大学）
- Waseda University（早稻田大学）
- Tongji University（同济大学）
- Asia Pacific Center for Theoretical Physics（亚太理论物理中心）
- Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo（东京大学宇宙物质起源世界顶尖研究中心（WPI））
机构由 AI 辅助整理，请以论文原文为准。
