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Entropy 2012, 14(7), 1203-1220;

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

Institute of Theoretical Physics, Beijing University of Technology, Beijing 100124, China
Department of Physics, Imperial College London, South Kensington campus, London, SW7 2AZ, UK
Kavli Institute for Theoretical Physics, Chinese Academy of Sciences, Beijing 100080, China
CCAST (World Lab.), P.O.Box 8730, Beijing 100080, China
Author to whom correspondence should be addressed.
Received: 1 May 2012 / Revised: 30 May 2012 / Accepted: 18 June 2012 / Published: 9 July 2012
(This article belongs to the Special Issue Modified Gravity: From Black Holes Entropy to Current Cosmology)
Full-Text   |   PDF [309 KB, uploaded 24 February 2015]


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. View Full-Text
Keywords: DBI Lagrangian; dark energy; sound speed DBI Lagrangian; dark energy; sound speed
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Zhang, X.; Zhang, Q.; Huang, Y. The Dark Energy Properties of the Dirac–Born–Infeld Action. Entropy 2012, 14, 1203-1220.

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