All cosmological observations to date are consistent with adiabatic, Gaussian and nearly
scale invariant initial conditions. These findings provide strong evidence for a particular …

An important unsolved problem that affects practically all attempts to connect string theory to
cosmology and phenomenology is how to distinguish effective field theories belonging to the …

We study a model of inflation in which a scalar field χ is non-minimally coupled to
Starobinsky's R 2 gravity. After transforming it to the Einstein frame, a new scalar field, the …

A bstract Speed matters. How the masses and spins of new particles active during inflation
can be read off from the statistical properties of primordial density fluctuations is well …

Massive particles produced during inflation leave specific signatures in soft limits of
correlation functions of primordial fluctuations. When the Goldstone boson of broken time …

A bstract We apply the effective field theory approach to quasi-single field inflation, which
contains an additional scalar field with Hubble scale mass other than inflaton. Based on the …

The analyticity of response functions and scattering amplitudes implies powerful relations
between low-energy observables and the underlying short-distance dynamics. These …

A bstract In quasi-single field inflation there are massive fields that interact with the inflaton
field. If these other fields are not much heavier than the Hubble constant during inflation (H) …

The effective field theory of cosmological perturbations stems from considering a
cosmological background solution as a state displaying spontaneous breaking of time …

Heavy scalar fields can undergo an instability during inflation as a result of their kinetic
couplings with the inflaton. This is known as the geometrical destabilization of inflation, as it …