10 papers
Ultra slow-turn inflation
Ana Achúcarro, Perseas Christodoulidis, Jinn-Ouk Gong +1
In standard multi-field models, tachyonic isocurvature perturbations generally indicate the presence of an instability. We revisit the stability of some known counterexamples and s…
Gravitational open effective field theory of inflation
Perseas Christodoulidis, Jinn-Ouk Gong
We construct a gravitational open extension of the effective field theory of inflation in the Schwinger-Keldysh framework. While physical symmetries allow many open operators in th…
Emergent structures in open EFTs
Perseas Christodoulidis
Open effective field theories provide a systematic framework for describing systems coupled to an environment, where dissipation, noise, and modified conservation laws naturally ar…
Robust non-minimal attractors in many-field inflation
Perseas Christodoulidis, Robert Rosati, Evangelos I. Sfakianakis
Multi-field inflation can be inherently non-predictive, with the exception of models with strong attractors. In this work, we focus on models with multiple scalar fields that are n…
New shape for cross-bispectra in Chern-Simons gravity
Perseas Christodoulidis, Jinn-Ouk Gong, Wei-Chen Lin +2
Chern-Simons gravity is known to suffer from graviton ghost production during inflation, which suppresses the parity-violating power spectrum at scales relevant to cosmic microwave…
Enhanced power spectra from multi-field inflation
Perseas Christodoulidis, Jinn-Ouk Gong
We investigate the enhancement of the power spectra large enough to produce primordial black holes in models with multiple scalar fields. We present analytic solutions for the pert…