3 papers
astro-ph.CO2026
A simple mechanism for the enhancement of the inflationary power spectrum
I. Dalianis, A. Katsis, N. Tetradis
The background evolution in two-field inflation can feature two distinct stages, corresponding to the evolution along two successive field directions. When the second stage occurs…
astro-ph.CO2024
Gravitational Waves from Collapse of Pressureless Matter in the Early Universe
Ioannis Dalianis, Chris Kouvaris
If an early matter phase of the Universe existed after inflation with the proper power spectrum, enhanced density perturbations can decouple from the Hubble flow, turn around and c…
astro-ph.CO2023
Features in the Inflaton Potential and the Spectrum of Cosmological Perturbations
Ioannis Dalianis
Cosmological perturbations, originating in the quantum fluctuations of the fields that drive inflation, are observed to be nearly scale invariant at the largest scales. At smaller…