AI 中文总结
本研究探讨3-形式暗能量解释宇宙双折射的可能性，通过分析两种算子耦合下的双折射角特性，发现其双折射可模仿或区分类轴子粒子的对应效应，取决于早期宇宙场构型。
AI 中文摘要
出于诸多原因，3-形式是宇宙学语境中值得研究的有趣场，例如它们可作为解释暴胀与暗能量的候选者。在膨胀宇宙中，3-形式场的背景演化与标量场相似但可区分，其张量结构允许正则标量无法实现的独特耦合。本研究探讨3-形式暗能量解释宇宙双折射的可能性，考虑两种受有效场论（EFT）启发的3-形式与光子的耦合，计算双折射角β。研究发现，维度-6规范不变算子需极大耦合才能解释观测到的宇宙微波背景辐射所暗示的β≈0.3°；而维度-4算子可在激发光子纵模的情况下容纳β≈0.3°。值得注意的是，要求自洽退耦极限意味着光子质量与H₀处于几个数量级范围内。研究还推导了β(z)的“普适”轮廓：维度-4算子的β对3-形式势的形式不敏感，但对初始条件敏感；相反，维度-6算子对势的形式高度敏感。最后，将这些普适轮廓与类轴子粒子（ALP）暗能量及超轻质量3-形式的轮廓对比，后者通过数值积分与ΛCDM低红移一致的宇宙学历史获得。结果表明，3-形式暗能量产生的双折射可模仿类轴子粒子的双折射，也可与之区分，取决于早期宇宙中的场构型。
英文摘要
3-forms are interesting fields to study in the cosmological context for numerous reasons, such as being candidates for explaining inflation and dark energy. The background evolution of a 3-form field is similar to but distinguishable from a scalar field in an expanding universe, and its tensorial structure allows for unique couplings that cannot be experienced by canonical scalars. In this work, we explore the possibility that 3-form dark energy can explain cosmic birefringence. We consider two EFT-inspired couplings between the 3-form and the photon, and compute the birefringence angle $β$. We find that a dimension-6 gauge-invariant operator necessitates an extremely large coupling to explain $β\sim0.3^\circ$, the value suggested by observations of recent cosmic microwave background radiation. Conversely, a dimension-4 operator can accommodate $β\sim0.3^\circ$ at the expense exciting the longitudinal mode of the photon. Interestingly, demanding a self-consistent decoupling limit implies the photon mass lies within a few orders of magnitude of $H_0$. We also derive `universal' profiles for $β(z)$, finding the $β$ from the dimension-4 operator is insensitive to the form of the 3-form potential but is sensitive to the initial conditions. Contrarily, the dimension-6 operator is highly sensitive to the form of the potential. We finally compare the universal profiles to that of axion-like particle (ALP) dark energy and an ultralight massive 3-form, the latter obtained from numerically integrated cosmological histories consistent with $Λ$CDM up to low redshift. Our results show that birefringence from 3-form dark energy can both mimic that from an ALP or be distinguishable, depending on the field configuration in the early universe.
Comments15 pages, 3 figures
