The current Universe is composed by a mixture of relativistic species, baryonic matter, dark matter and dark energy which evolve in a non-trivial way at perturbative level. An advanced description of the cosmological dynamics should include non-standard features beyond the simplistic approach idealized by the standard cosmology in which cosmic components do not interact, are adiabatic and dissipationless. We promote a full perturbative analysis of linear scalar perturbations of a non-interacting cosmological model containing baryons, dark matter (both pressureless) and a scalar field allowing for the presence of relative entropic perturbations between the three fluids. Assuming an effective scalar-field sound speed equal to one and neglecting anisotropic stresses we establish a new set of equations for the scalar cosmological perturbations. As a consequence of this new approach, we show that tiny departures from a constant scalar field equation of state $w_S=-1$ damage structure formation in a non-acceptable manner. Hence, by strongly constraining $w_S$ our results provide compelling evidence in favor of the standard cosmological model and rule out a large class of dynamical dark energy models.

当前的宇宙由相对论物种，重子物质，暗物质和暗能量的混合物组成，它们以微不足道的方式在扰动水平上演化。对宇宙动力学的高级描述应包括非标准特征，这超出了标准宇宙学理想化的简单方法，在该方法中，宇宙成分不相互作用，绝热且无耗散。我们提倡对包含重子，暗物质（均无压力）和标量场的非相互作用宇宙学模型的线性标量摄动进行完全摄动分析，以允许三种流体之间存在相对的熵摄动。假设有效的标量场声速等于1并忽略各向异性应力，我们建立了标量宇宙扰动的一组新方程。$w_{\mathrm{小号}}=-\mathrm{1个}$以不可接受的方式破坏结构的形成。因此，通过严格约束$w_{\mathrm{小号}}$ 我们的结果提供了支持标准宇宙学模型的令人信服的证据，并排除了一大类动态暗能量模型。