Description
Bimetric theories employing a disformal transformation between matter and gravity metrics are known to be capable of producing both exactly scale-invariant as well as tilted power spectra of perturbations. I will present results for the non-Gaussian signal obtained in these scenarios, which has an amplitude smaller than that of DBI inflation (with opposite sign) but larger than standard inflation. Interestingly this also gives rise to a constraint relating the spectral index and the non-Gaussian amplitude, which can be seen as a ?consistency relation? for bimetric models. In fact this constraint can be generalised and I will extend our result to apply to the general class of k-essence models.
| ArXiv number (if any) | 1006.3216 |
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