Tensor-to-scalar ratio in punctuated inflation
- Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019 (India)
- Korea Institute for Advanced Study, 207-43 Cheongnyangni 2-dong, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of)
- IUCAA, Post Bag 4, Ganeshkhind, Pune 411 007 (India)
Recently, we have shown that scalar spectra with lower power on large scales and certain other features naturally occur in punctuated inflation, i.e. the scenario wherein a brief period of rapid roll is sandwiched between two stages of slow roll inflation. Such spectra gain importance due to the fact that they can lead to a better fit of the observed CMB anisotropies, when compared to the conventional, featureless, power law spectrum. In this paper, with examples from the canonical scalar field as well as the tachyonic models, we illustrate that, in punctuated inflation, a drop in the scalar power on large scales is always accompanied by a rise in the tensor power and, hence, an even more pronounced increase in the tensor-to-scalar ratio r on these scales. Interestingly, we find that r actually exceeds well beyond unity over a small range of scales. To our knowledge, this work presents for the first time, examples of single scalar field inflationary models wherein r>>1. This feature opens up interesting possibilities. For instance, we show that the rise in r on large scales translates to a rapid increase in the angular power spectrum, C{sub l}{sup BB}, of the B-mode polarization of the CMB at the low multipoles. We discuss the observational implications of these results.
- OSTI ID:
- 21415216
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 82, Issue 2; Other Information: DOI: 10.1103/PhysRevD.82.023509; (c) 2010 The American Physical Society; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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