Non-Bunch–Davis initial state reconciles chaotic models with BICEP and Planck

• DOI: 10.1016/j.physletb.2014.08.038
• Publication Date: 2014-08-19T12:45:31Z
• Authors: Amjad Ashoorioon; Konstantinos Dimo...; Mohammad M. Sheik...; Gary Shiu
• Keywords: Spectral index

The BICEP2 experiment has announced a signal for primordial gravity waves with tensor-to-scalar ratio $r=0.2^{+0.07}_{-0.05}$ [arXiv:1403.3985]. There are two ways to reconcile this result the latest Planck [arXiv:1303.5082]. One is by assuming that there considerable tilt of $r$, $\mathcal{T}_r$, positive sign, $\mathcal{T}_r=d\ln r/d\ln k\gtrsim 0.57^{+0.29}_{-0.27}$ corresponding blue tensor modes order $n_T\simeq0.53 ^{+0.29}_{-0.27}$, best-fit value scalar power spectrum $n_S$. other possibility assume negative running in spectral index, $dn_S/d\ln k\simeq -0.02$ which pushes up upper bound on $r$ from $0.11$ $0.26$ analysis existence spectrum. Simple slow-roll models fail provide such large values $\mathcal{T}_r$ or runnings $n_S$ In note we show non-Bunch-Davies initial state perturbations can match between field chaotic (like $m^2\phi^2$) [arXiv:1306.4914] and results accommodating either