5 papers
Tachyonic Encore: A universal shift of inflationary observables
Diogo S. Gorgulho, Margherita Putti, Rodrigo Gonzalez Quaglia +3
We propose a generic, largely inflaton-potential-independent mechanism in which a light axion spectator, initialized near the hilltop of its potential, reshapes inflationary observ…
Towards a Heterotic Axiverse
Jacob M. Leedom, Margherita Putti, Alexander Westphal
In this paper we initiate a broad study of some central properties of the string axiverse arising from Calabi-Yau compactifications of the perturbative heterotic th…
Preheating Axions in String Cosmology
Jacob M. Leedom, Margherita Putti, Nicole Righi +1
Certain inflationary models can feature periods of preheating - an era preceding reheating during which parametric resonance triggers an exponential production of bosons. This non-…
CMB spectral distortions from enhanced primordial perturbations: the role of spectator axions
Margherita Putti, Nicola Bartolo, Sukannya Bhattacharya +1
Primordial tensor modes can induce Cosmic Microwave Background spectral distortions during horizon re-entry. We investigate a specific mechanism proposed for this purpose, characte…
Gravitational Axiverse Spectroscopy: Seeing the Forest for the Axions
Ema Dimastrogiovanni, Matteo Fasiello, Jacob M. Leedom +2
We consider inflationary models with multiple spectator axions coupled to dark gauge sectors via Chern-Simons (CS) terms. The energy injection into Abelian gauge fields from the ax…