While detection of the "local form" bispectrum of primordial perturbations would rule out all single-field inflation models, multifield models would still be allowed. We show that multifield models described by the δN formalism obey an inequality between fNL and one of the local-form trispectrum amplitudes, τNL, such that τNL>12(65fNL)2 with a possible logarithmic scale dependence, provided that 2-loop terms are small. Detection of a violation of this inequality would rule out most of multifield models, challenging inflation as a mechanism for generating the primoridal perturbations.
ASJC Scopus subject areas
- Physics and Astronomy(all)