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摘要
We study the dynamical stability of tachyacoustic cosmological models, in which primordial perturbations are generated by a shrinking sound horizon during a period of decelerating expansion. Such models represent a potential alternative to inflationary cosmology, but the phase-space behavior of tachyacoustic solutions has not previously been investigated. We numerically evaluate the dynamics of two noncanonical Lagrangians, a cuscuton-like Lagrangian and a Dirac-Born-Infeld Lagrangian, which generate a scale-invariant spectrum of perturbations. We show that the power-law background solutions in both cases are dynamical attractors.
- 出版日期2012-10-1
