Enhancing Inflationary Tensor Modes through Spectator Fields

Abstract

We show that a large contribution to tensor modes during inflation can be generated by a spectator scalar field with speed of sound lower than unity.

Figures (2)

• Figure 1: The normalized tensor mode power spectrum as a function of $(-k\tau)$. Either $k$ or $\tau$ can be kept fixed, both choices will generate the behavior above.
• Figure 2: The normalized tensor mode power spectrum as a function of $c_s$ on super-Hubble scales (red triangles) with superimposed the function with scaling $c_s^{-18/5}$.