The Dark Energy Properties of the Dirac–Born–Infeld Action

Entropy

Xinyou Zhang¹  Qing Zhang² 

[1] Institute of Theoretical Physics, Beijing University of Technology, Beijing 100124, China; E-Mail:;Department of Physics, Imperial College London, South Kensington campus, London, SW7 2AZ, UK; E-Mail:

关键词: DBI Lagrangian;    dark energy;    sound speed;   

DOI  :  10.3390/e14071203

来源: mdpi

【 摘 要 】

Introducing a new potential, we deduce a general Lagrangian for Dirac–Born– Infeld (DBI) inflation, in which the determinant of the induced metric naturally includes the kinetic energy and the potential energy. In particular, the potential energy and kinetic energy can convert into each other at any same order, which is in agreement with the limit of classical physics. We also present a general sound speed in the evolutions of the universe, and the exact expressions of energy-momentum tensor, pressure and density. Furthermore, from the results we obtain the new equation of states. The analytic form of the action that is consistent with data turns out to be surprisingly simple and easy to categorize. Finally, we examine properties of the dark energy and introduce a novel mechanism for realizing either quintessence or phantom dark energy dominated phases within a string theoretical context.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.