10 research outputs found
Primordial non-Gaussianity from Galilean Genesis without strong coupling problem
Galilean Genesis is generically plagued with a strong coupling problem, but
this can be avoided depending on the hierarchy between a classical energy scale
of genesis and a strong coupling scale. In this paper, we investigate whether
or not the models of Galilean Genesis without the strong coupling problem can
explain the statistical properties of the observed CMB fluctuations based on
two unified frameworks of Galilean Genesis. By focusing on the class in which
the propagation speeds of the scalar and tensor perturbations are constant, we
show that the models avoiding strong coupling and allowing a slightly
red-tilted scalar power spectrum suffer from an overproduction of a scalar
non-Gaussianity.Comment: 16 pages, 1 figur