Abstract

We investigate the Universe at the late stage of its evolution and inside the cell of uniformity, 150–370 Mpc. We consider the Universe to be filled at these scales with dustlike matter, a minimally coupled Galileon field and radiation. We use the mechanical approach. Therefore, the peculiar velocities of the inhomogeneities as well as the fluctuations of other perfect fluids can be considered nonrelativistic. Such fluids are said to be coupled because they are concentrated around the inhomogeneities. We investigate the conditions under which the physical Galileon field, i.e., the field compatible with the results of the latest gravitational wave experiments GW150914, GW151226, GW170104, GW170814, GW170817 and GW170608, can become coupled. We know that at the background level coupled scalar fields behave as two-component perfect fluids: one which mimics a network of frustrated cosmic strings and another one which corresponds to an effective cosmological constant. We found as well a correction for the Galileon field, which behaves like a matter component.

中文翻译：

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晚期宇宙力学方法中伽利略宇宙的标量摄动

摘要

我们在宇宙演化的后期和均匀度为150-370 Mpc的细胞内研究宇宙。我们认为宇宙在这些尺度上充满了尘埃状物质，最小耦合的伽利略场和辐射。我们使用机械方法。因此，不均匀性的奇特速度以及其他完美流体的波动可以被认为是非相对论的。据说这些流体是耦合的，因为它们集中在不均匀性周围。我们研究了物理伽利略场（即与最新引力波实验GW150914，GW151226，GW170104，GW170814，GW170817和GW170608的结果兼容的场）可以耦合的条件。我们知道，在背景水平上，耦合的标量场表现为两成分的完美流体：一个模拟沮丧的宇宙弦网络，另一个模拟有效的宇宙学常数。我们还发现了对伽利略域的修正，其行为类似于物质成分。