Initial Conditions for Non-Canonical Inflation

Abstract

We investigate the dynamics of homogeneous phase space for single-field models of inflation. Inflationary trajectories are formally attractors in phase space, but since in practice not all initial conditions lead to them, some degree of fine tuning is required for successful inflation. We explore how the dynamics of non-canonical inflation, which has additional kinetic terms that are powers of the kinetic energy, can play a role in ameliorating the initial conditions fine tuning problem. We present a qualitative analysis of inflationary phase space based on the dynamical behavior of the scalar field. This allows us to construct the flow of trajectories, finding that trajectories generically decay towards the inflationary solution at a steeper angle for non-canonical kinetic terms, in comparison to canonical kinetic terms, so that a larger fraction of the initial-conditions space leads to inflation. Thus, non-canonical kinetic terms can be important for removing the initial conditions fine-tuning problem of some small-field inflation models.

15 pages, 9 figures

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• Intermediate inflation from a non-canonical scalar field
• Brane Constant-roll Inflation
• Tsallis holographic dark energy for inflation
• Warm Tachyon Inflation and Swampland Criteria
• Warm DBI inflation with constant sound speed
• Beta-function formalism for k-essence constant-roll inflation
• Relations between canonical and non-canonical inflation
• Tachyon inflation with steep potentials
• Brane inflation and Trans-Planckian censorship conjecture
• Brans-Dicke inflation in light of the Planck 2015 data
• Preheating with the Brakes On: The Effects of a Speed Limit
• Inflation with non-canonical scalar fields revisited
• Holographic warm inflation
• Inflation with exotic kinetic terms in Einstein-Chern-Simons gravity
• Tsallis holographic inflation in $f(R,T)$ gravity: CMB constraints, reheating, and swampland implications
• Non-canonical scalar field in low anisotropy universe with intermediate inflation