摘要
We restrict purely kinetic k-essence.Assuming that the equation of state is a power law of the kinetic energy,i.e.w=w0Xα,we find thatαmust be positive to obtain accelerated phases,constrained from the conditions for stability and causality.In this case the k-essence behaves like a phantom.We also study the evolutions of the equation of state and the speed of sound with numerical simulations.
作者
杨荣佳
祁景钊
杨宝柱
YANG Rong-Jia;QI Jing-Zhao;YANG Bao-Zhu(College of Physical Science and Technology,Hebei University,Baoding 071002)
基金
Supported in part by the Natural Science Foundation of Hebei Province under Grant No.A2011201147
the Research Fund for Doctoral Programs of Hebei University under Grant No.2009-155
the Open Research Topics Fund of Key Laboratory of Particle Astrophysics,Institute of High Energy Physics,Chinese Academy of Sciences,under Grant No.0529410T41-200901.
