162 citations · 2k across the 45 of their papers we have counts for
19 papers · 1 filter
Hyperbolic field space and swampland conjecture for DBI scalar
Shuntaro Mizuno, Shinji Mukohyama, Shi Pi +1
We study a model of two scalar fields with a hyperbolic field space and show that it reduces to a single-field Dirac-Born-Infeld (DBI) model in the limit where the field space beco…
-attractor-type Double Inflation
Kei-ichi Maeda, Shuntaro Mizuno, Ryota Tozuka
We study the background dynamics and primordial perturbation in -attractor-type double inflation. The model is composed of two minimally coupled scalar fields, where each of the…
Primordial perturbations from inflation with a hyperbolic field-space
Shuntaro Mizuno, Shinji Mukohyama
We study primordial perturbations from hyperinflation, proposed recently and based on a hyperbolic field-space. In the previous work, it was shown that the field-space angular mome…
Cosmological Dynamics of D-BIonic and DBI Scalar Field and Coincidence Problem of Dark Energy
Sirachak Panpanich, Kei-ichi Maeda, Shuntaro Mizuno
We study the cosmological dynamics of D-BIonic and DBI scalar field, which is coupled to matter fluid. For the exponential potential and the exponential couplings, we find a new an…
Vainshtein mechanism in massive gravity nonlinear sigma models
Katsuki Aoki, Shuntaro Mizuno
We study the stability of the Vainshtein screening solution of the massive/bi-gravity based on the massive nonlinear sigma model as the effective action inside the Vainshtein radiu…
Combined features in the primordial spectra induced by a sudden turn in two-field DBI inflation
Shuntaro Mizuno, Ryo Saito, David Langlois
We investigate the features generated by a sharp turn along the inflationary trajectory in a two-field model of Dirac-Born-Infeld inflation, where one of the fields is heavy. Disti…