We investigate the physical properties of a purely kinetic k-essence model with an equation of state motivated in superconducting membranes. We compute the equation of state parameter $w$ and discuss its physical evolution via a nonlinear equation of state. Using the adiabatic speed of sound and energy density, we restrict the range of parameters of the model in order to have an acceptable physical behavior. Furthermore, we analyze the evolution of the luminosity distance $d_{L}$ with redshift $z$ by comparing (normalizing) it with the $Λ$CDM model. Since the equation of state parameter is $z$-dependent the evolution of the luminosity distance is also analyzed using the Alcock-Paczyński test.
Unified Dark Energy and Dust Dark Matter Dual to Quadratic Purely Kinetic K-Essence
我们考虑一个修正的引力加单标量场模型,其中标量拉格朗日量对称地耦合到由黎曼度量行列式的平方根给出的标准黎曼体积形式(时空积分测度密度),以及另一个以辅助最大秩反对称张量规范场表示的非黎曼体积形式.正如在以前的论文中所示,相关的标量场动力学提供了一个精确的统一描述的暗能量通过动态生成的宇宙学常数,和暗物质作为一个“尘埃”流体与测地线流作为一个隐藏的诺特对称性的结果。在这里,我们通过考虑纯引力作用量的一个非平凡的修正,即f(R)= R - αR^2广义引力来扩展讨论。在导出后一种修正的引力标量场理论的相应的“爱因斯坦框架”有效作用量时,我们发现了明确的对偶性(在弱耦合与强耦合的意义上)统一动力学暗能量和尘埃流体暗物质的原始模型之间,一方面,一个特定的二次纯动力学“k本质”引力物质模型,其耦合常数仅对两个独立参数有特殊的依赖性,另一方面,本文还简要讨论了对偶纯动力学“k-本质”引力-物质模型的正则哈密顿处理和Wheeler-DeWitt量子化。
From Dark Radiation to Dark Energy: Unified Cosmological Evolution in K-essence Models
Universidad de Guanajuato(瓜纳华托大学);Centro de Investigación y de Estudios Avanzados del I.P.N.(墨西哥国立自治研究所高级研究中心);Secretaría de Ciencia, Humanidades, Tecnología e Innovación(科学、人文、技术与创新秘书处)
Fine Tuning Free Paradigm of Two Measures Theory: K-Essence, Absence of Initial Singularity of the Curvature and Inflation with Graceful Exit to Zero Cosmological Constant State