Purely kinetic k-essence models have been shown in the literature to be a field theory equivalent of barotropic fluid models of dark energy or dark matter–dark energy unification. In the modeling framework where the speed of sound squared of a barotropic fluid is modeled as a function of its Equation of State parameter, a systematic procedure of obtaining the Lagrangian density of an equivalent purely kinetic k-essence model is presented. As this modeling approach starts from the speed of sound, purely kinetic k-essence models can be constructed for which the speed of sound is in agreement with the observational constraints. Depending on the chosen functional form for the barotropic fluid speed of sound squared, analytically tractable examples of solutions for the purely kinetic k-essence Lagrangian density in parametric and closed form are obtained.

文献中已经证明，纯动力学k本质模型是等效于暗能量或暗物质-暗能量统一的正压流体模型的场论。在建模框架中，将正压流体的声平方作为其状态方程参数的函数进行建模，提出了获得等效纯动力学k本质模型的拉格朗日密度的系统程序。由于这种建模方法是从声音的速度开始的，因此可以构建纯动力学的k-essence模型，对于该模型，声音的速度与观察约束条件是一致的。取决于为正压流体速度平方选择的函数形式，