activity
20112022
most citedPhenomenology of a Pseudo-Scalar Inflaton: Naturally Large Nongaussianity

247 citations · 2k across the 37 of their papers we have counts for

collaborators

37 papers

hep-ph2022

Peaky Production of Light Dark Photon Dark Matter

Yuichiro Nakai, Ryo Namba, Ippei Obata

We explore a mechanism to produce a light dark photon dark matter through a coupling between the dark photon field and a spectator scalar field which plays no role in the inflation…

gr-qc2022★ 19 cited

Bouncing Cosmology in VCDM

Alexander Ganz, Paul Martens, Shinji Mukohyama +1

We construct an asymmetric bouncing scenario within the VCDM model - also known as type-II minimally modified gravity -, a modified gravity theory with two local physical degrees o…

hep-th2022★ 1 cited

Reheating after relaxation of large cosmological constant

Paul Martens, Shinji Mukohyama, Ryo Namba

We present a cosmological model of an early-time scenario that incorporates a relaxation process of the would-be large vacuum energy, followed by a reheating era connecting to the…

hep-ph2022★ 14 cited

Universality of linear perturbations in SU()-natural inflation

Tomohiro Fujita, Kai Murai, Ryo Namba

We prove the universality of predictions for linear perturbations from the entire class of models of inflation driven by a pseudo-scalar field coupled to an SU() gauge boson, wh…

hep-th2021

Positivity vs. Lorentz-violation: an explicit example

Katsuki Aoki, Shinji Mukohyama, Ryo Namba

We show how a class of multi-field scalar-field theories in a Lorentz-breaking background imposes consistency conditions on its effective theory of a single field and provides an e…

hep-th2020★ 11 cited

Partial UV Completion of from a Curved Field Space

Shinji Mukohyama, Ryo Namba

The -essence theory is a prototypical class of scalar-field models that already gives rich phenomenology and has been a target of extensive studies in cosmology. General forms o…