论文标题
拉格朗日的宇宙流体描述：将深色能量映射到统一的黑暗能源
Lagrangian description of cosmic fluids: mapping dark energy into unified dark energy
论文作者
论文摘要
我们研究了使用不同拉格朗日人来描述宇宙能量预算的各种组成部分的适当性，并在没有与重力或其他领域的非微小耦合的情况下讨论了它们之间的变性，并阐明了文献中的一些误解。我们进一步证明，对于非微小耦合流体，这些脱位通常被打破，在这种情况下，适当的壳内lagrangian的识别可能是必不可少的，以表征整体动力学。然后，我们证明具有相同壳lagrangian的模型可能具有不同的适当能量密度，并使用此结果将深色能量模型映射到统一的深色能量模型中，其中暗物质和深色能量由相同的完美流体描述。我们确定其状态参数方程与声速之间的对应关系，简要讨论了统一的暗能量模型的线性音速问题以及与非线性动力学相关的可能出路。
We investigate the appropriateness of the use of different Lagrangians to describe various components of the cosmic energy budget, discussing the degeneracies between them in the absence of nonminimal couplings to gravity or other fields, and clarifying some misconceptions in the literature. We further demonstrate that these degeneracies are generally broken for nonminimal coupled fluids, in which case the identification of the appropriate on-shell Lagrangian may become essential in order characterize the overall dynamics. We then show that models with the same on-shell Lagrangian may have different proper energy densities and use this result to map dark energy models into unified dark energy models in which dark matter and dark energy are described by the same perfect fluid. We determine the correspondence between their equation of state parameters and sound speeds, briefly discussing the linear sound speed problem of unified dark energy models as well as a possible way out associated to the nonlinear dynamics.
