亚视界与准静态近似在涉及标量场暗能量的相互作用暗区模型中的应用
Sub-Horizon and Quasi-Static Approximations in Interacting Dark Sector Models Involving Scalar Field Dark Energy
- Indian Institute of Technology, Kanpur（坎普尔印度理工学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究验证了相互作用标量场暗能量模型中亚视界和准静态近似的有效性，发现SHA在高相互作用和小波数下误差增大，QSA更优，且SHA不能仅凭亚视界条件假设成立。
AI中文摘要：
我们研究了相互作用标量场暗能量模型中线性物质扰动的亚视界近似（SHA）和准静态近似（QSA）的有效性。我们考虑了quintessence和phantom标量场，并推导了它们的完整相对论性扰动演化，以与相应的SHA和QSA解进行比较。我们发现，对于非相互作用和弱相互作用模型，在足够亚视界的尺度上，SHA能以百分之一的精度重现完整演化，但其精度随着相互作用强度的增加和向更大尺度的推进而逐渐下降。此外，与ΛCDM和非相互作用标量场模型不同，将SHA应用于相互作用模型并不能完全恢复标准的牛顿流体方程。在所考虑的尺度上，QSA通常比SHA更接近完整的相对论性演化。通过将标量场模型与ΛCDM分别使用完整相对论性方程和SHA系统进行比较，我们评估了SHA是否能够捕捉替代模型引入的全部物理差异。我们发现，这两种比较之间的差异在更强的相互作用和更小的波数下变得越来越重要。最后，我们证明，在大体积流体动力学模拟可及的尺度上，由此产生的差异可达几个百分点，这意味着SHA的有效性不能仅从亚视界条件来假设。我们的结果强调，在将相互作用暗能量模型用于大体积结构形成模拟和与大规模结构观测的精度比较之前，需要在相关的相互作用参数和波数范围内对近似进行基准测试。
英文摘要：
We investigate the validity of the sub-horizon approximation (SHA) and quasi-static approximation (QSA) for linear matter perturbations in interacting scalar-field dark-energy models. We consider both quintessence and phantom scalar fields and derive their full relativistic perturbation evolution to compare with the corresponding SHA and QSA solutions. We find that, while the SHA reproduces the full evolution with percent-level accuracy for non-interacting and weakly interacting models on sufficiently sub-horizon scales, its accuracy progressively deteriorates with increasing interaction strength and towards larger scales. Moreover, unlike in $Λ$CDM and non-interacting scalar-field models, applying the SHA to interacting models does not fully recover the standard Newtonian fluid equations. The QSA generally provides a closer description of the full relativistic evolution than the SHA over the scales considered. By comparing the scalar-field model with $Λ$CDM using the full relativistic equations and, separately, using the SHA system, we evaluated whether the SHA is capable of capturing the full extent of the physical differences introduced by the alternative model. We find that the difference between these two comparisons becomes increasingly important for stronger interactions and smaller wavenumbers. Finally, we demonstrate that the resulting differences can reach several percent on scales accessible to large-volume hydrodynamical simulations, implying that the validity of the SHA cannot be assumed solely from the sub-horizon condition. Our results highlight the need to benchmark the approximation over the relevant interaction parameter and wavenumber ranges before employing interacting-dark-energy models in large-volume structure-formation simulations and precision comparisons with large-scale-structure observations.
