Cosmological dynamics of a dirac-born-infeld field

Edmund J. Copeland, Shuntaro Mizuno, Maryam Shaeri

研究成果: Article査読

27 被引用数 (Scopus)


We analyze the dynamics of a Dirac-Born-Infeld (DBI) field in a cosmological setup which includes a perfect fluid. Introducing convenient dynamical variables, we show that the evolution equations form an autonomous system when the potential and the brane tension of the DBI field are arbitrary power law or exponential functions of the DBI field. In particular we find scaling solutions can exist when powers of the field in the potential and warp factor satisfy specific relations. A new class of fixed-point solutions are obtained corresponding to points which initially appear singular in the evolution equations, but on closer inspection are actually well defined. In all cases, we perform a phase-space analysis and obtain the late-time attractor structure of the system. Of particular note when considering cosmological perturbations in DBI inflation is a fixed-point solution where the Lorentz factor is a finite large constant and the equation of state parameter of the DBI field is w=-1. Since in this case the speed of sound cs becomes constant, the solution can be thought to serve as a good background to perturb about.

ジャーナルPhysical Review D - Particles, Fields, Gravitation and Cosmology
出版ステータスPublished - 2010

ASJC Scopus subject areas

  • 核物理学および高エネルギー物理学


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