347 citations · 887 across the 11 of their papers we have counts for
4 papers · 1 filter
WMAP constraints on scalar-tensor cosmology and the variation of the gravitational constant
Ryo Nagata, Takeshi Chiba, Naoshi Sugiyama
We present observational constraints on a scalar-tensor gravity theory by test for CMB anisotropy spectrum. We compare the WMAP temperature power spectrum with the harmonic a…
Reheating After Quintessential Inflation and Gravitational Waves
Hiroyuki Tashiro, Takeshi Chiba, Misao Sasaki
We investigate the dependence of the gravitational wave spectrum from quintessential inflation on the reheating process. We consider two extreme reheating processes. One is the gra…
1/R gravity and Scalar-Tensor Gravity
Takeshi Chiba
We point out that extended gravity theories, the Lagrangian of which is an arbitrary function of scalar curvature , are equivalent to a class of the scalar tensor theories of gr…
Supernova Cosmology and the Fine Structure Constant
Takeshi Chiba, Kazunori Kohri
We study the dependence of the peak luminosity of Type Ia supernovae on the fine structure constant . We find that decreasing (increasing) enhances (reduces) the luminosity.…