Pre-inflationary genesis with CMB B-mode polarization

Abstract

Recent B-mode polarization observation seems to imply the tensor tilt $n_T\gtrsim 1$ at large angular scale, if the primordial signal is dominated. We show that for a primordial universe, which is in a slowly expanding genesis phase before the slow-roll inflation, the primordial tensor spectrum will get a large-scale cutoff, i.e. $n_T\gtrsim 1$ at large scales while $n_T\simeq 0$ at small scale. We find that this inflationary scenario not only may be consistent with the observation, but also predicts a large-scale anomaly in BB power spectrum, i.e. due to the large suppression of tensor perturbation amplitude we will hardly see the reionization bump at low-$l$, which may be falsified by the Planck polarization data.

minor changes, in PRD

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Cited by in corpus (7)

• The Effective Field Theory of nonsingular cosmology
• Pre-inflationary primordial perturbations
• Scale-invariant perturbations from NEC violation: A new variant of Galilean Genesis
• Probing the primordial universe with gravitational waves detectors
• Perturbative unitarity and NEC violation in genesis cosmology
• Precision of future experiments measuring primordial tensor fluctuation
• Thermal gravitational-wave background in the general pre-inflationary scenario