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Publication . Article . Preprint . 2015

Gravitational Wave Consistency Relations for Multifield Inflation

Layne C. Price; Hiranya V. Peiris; Jonathan Frazer; Richard Easther;
Open Access  
Published: 22 Jan 2015 Journal: Physical Review Letters, volume 114 (issn: 0031-9007, eissn: 1079-7114, Copyright policy )
Publisher: American Physical Society (APS)
Country: United Kingdom
Abstract
We study the tensor spectral index $n_t$ and the tensor-to-scalar ratio $r$ in the simplest multifield extension to single-field, slow-roll inflation models. We show that multifield models with potentials $V \sim \sum_i \lambda_i |\phi_i|^p$ have different predictions for $n_t/r$ than single-field models, even when all the couplings are equal $\lambda_i=\lambda_j$, due to the probabilistic nature of the fields' initial values. We analyze well-motivated prior probabilities for the $\lambda_i$ and initial conditions to make detailed predictions for the marginalized probability distribution of $n_t/r$. With $\mathcal O(100)$ fields and $p>3/4$, we find that $n_t/r$ differs from the single-field result of $n_t/r=-1/8$ at the 5$\sigma$ level. This gives a novel and testable prediction for the simplest multifield inflation models.
Comment: 6 pages, 3 figures; v2: discussion updated, matches version accepted by Phys. Rev. Letters
Subjects by Vocabulary

Microsoft Academic Graph classification: Gravitational wave Tensor Physics Consistency (statistics) Theoretical physics Spectral index Inflation (cosmology) Observational cosmology Probability distribution

Subjects

General Physics and Astronomy, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology, High Energy Physics - Theory, Science & Technology, Physical Sciences, Physics, Multidisciplinary, Physics, FLUX COMPACTIFICATIONS

Funded by
NSF| Programs on Critical Problems in Physics, Astrophysics and Biophysics at the Aspen Center for Physics
Project
  • Funder: National Science Foundation (NSF)
  • Project Code: 1066293
  • Funding stream: Directorate for Mathematical & Physical Sciences | Division of Physics
,
EC| COSMICDAWN
Project
COSMICDAWN
Understanding the Origin of Cosmic Structure
  • Funder: European Commission (EC)
  • Project Code: 306478
  • Funding stream: FP7 | SP2 | ERC
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UCL Discovery
Article . 2015
Providers: UCL Discovery