Can we distinguish early dark energy from a cosmological constant?
Can we distinguish early dark energy from a cosmological constant?
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我们能区分早期暗能量和宇宙常数吗？
DOI：
10.1093/mnras/stw882
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发表时间：
2016
影响因子：
4.8
通讯作者：
Shi D
中科院分区：
文献类型：
--
作者：
Shi D
早期暗能量（EDE）模型是一类具有动态演化标量场的经典暗能量模型，它在物质辐射相等的时期显示出少量但不可忽略的暗能量。与宇宙学常数相比，早期暗能量的存在改变了宇宙膨胀的历史，从而改变了线性理论功率谱的形状，并可能改变其他观测值。我们约束的宇宙学参数在EDE宇宙学使用最近的测量宇宙微波背景和重子声振荡。最佳拟合的模型有利于没有EDE，在这里，我们考虑极端的例子是在温和的紧张局势与当前的观测，以探讨观测结果的最大允许量的EDE。本文利用大体积N体模拟研究了EDE宇宙学中宇宙结构的非线性演化。在Λ冷暗物质（ΛCDM）模型和EDE模型之间发现了许多非常相似的大尺度结构统计。我们发现，EDE宇宙学预测较少的质量晕相比，ΛCDM，特别是在高红移。区分EDE和ΛCDM的最有希望的方法是在大尺度上测量功率谱，预计差异高达15%。
Early dark energy (EDE) models are a class of quintessence dark energy with a dynamically evolving scalar field which display a small but non-negligible amount of dark energy at the epoch of matter-radiation equality. Compared with a cosmological constant, the presence of dark energy at early times changes the cosmic expansion history and consequently the shape of the linear theory power spectrum and potentially other observables. We constrain the cosmological parameters in the EDE cosmology using recent measurements of the cosmic microwave background and baryon acoustic oscillations. The best-fitting models favour no EDE; here we consider extreme examples which are in mild tension with current observations in order to explore the observational consequences of a maximally allowed amount of EDE. We study the non-linear evolution of cosmic structure in EDE cosmologies using large-volumeN-body simulations. Many large-scale structure statistics are found to be very similar between the Λ cold dark matter (ΛCDM) and EDE models. We find that EDE cosmologies predict fewer massive haloes in comparison to ΛCDM, particularly at high redshifts. The most promising way to distinguish EDE from ΛCDM is to measure the power spectrum on large scales, where differences of up to 15 per cent are expected.