The Lambda-Cold Dark Matter (LCDM) model agrees with most of the cosmological observations, but has some hindrances from observed data at smaller scales such as galaxies. Recently, Berezhiani and Khoury (2015) proposed a new theory involving interacting superfluid dark matter with three model parameters, which explains galactic dynamics with great accuracy. In the present work, we study the cosmological behaviour of this model in the linear regime of cosmological perturbations. In particular, we compute both analytically and numerically the matter linear growth factor and obtain new bounds for the model parameters which are significantly stronger than previously found. These new constraints come from the fact that structures within the superfluid dark matter framework grow quicker than in LCDM, and quite rapidly when the DM-baryon interactions are strong.

中文翻译：

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具有超流体暗物质的宇宙中线性扰动的增长

Lambda-冷暗物质 (LCDM) 模型与大多数宇宙学观测结果一致，但在较小尺度（如星系）的观测数据中存在一些障碍。最近，Berezhiani 和 Khoury (2015) 提出了一个新理论，该理论涉及具有三个模型参数的超流体暗物质相互作用，该理论非常准确地解释了星系动力学。在目前的工作中，我们研究了该模型在宇宙学扰动的线性状态下的宇宙学行为。特别是，我们通过分析和数值计算了物质线性增长因子，并获得了比以前发现的模型参数强得多的新界限。这些新的限制来自这样一个事实，即超流体暗物质框架内的结构比 LCDM 中的结构增长得更快，