Please use this identifier to cite or link to this item: https://hdl.handle.net/1783.1/85824
CMB Scale Dependent Non-Gaussianity from Massive Gravity During Inflation
| Author |
Domenech, Guillem
Hiramatsu, Takashi Lin, Chunshan Sasaki, Misao Shiraishi, Maresuke Wang, Yi 
|
|---|---|
| Issue Date | 2017 |
| Source | Journal of Cosmology and Astroparticle Physics, v. 2017, (5), May 2017, article number 034 |
| Abstract | We consider a cosmological model in which the tensor mode becomes massive during inflation, and study the Cosmic Microwave Background (CMB) temperature and polarization bispectra arising from the mixing between the scalar mode and the massive tensor mode during inflation. The model assumes the existence of a preferred spatial frame during inflation. The local Lorentz invariance is already broken in cosmology due to the existence of a preferred rest frame. The existence of a preferred spatial frame further breaks the remaining local SO(3) invariance and in particular gives rise to a mass in the tensor mode. At linear perturbation level, we minimize our model so that the vector mode remains non-dynamical, while the scalar mode is the same as the one in single-field slow-roll inflation. At non-linear perturbation level, this inflationary massive graviton phase leads to a sizeable scalar-scalar-tensor coupling, much greater than the scalar-scalar-scalar one, as opposed to the conventional case. This scalar-scalar-tensor interaction imprints a scale dependent feature in the CMB temperature and polarization bispectra. Very intriguingly, we find a surprizing similarity between the predicted scale dependence and the scale-dependent non-Gaussianities at low multipoles hinted in the WMAP and Planck results. |
| Subject | |
| DOI | 10.1088/1475-7516/2017/05/034 |
| ISSN | 1475-7516 |
| Language | English |
| Type | Article |
| RGC funded | Yes |
| Access |
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