74 citations · 224 across the 9 of their papers we have counts for
9 papers
Generation of neutrino dark matter, baryon asymmetry, and radiation after quintessential inflation
Kohei Fujikura, Soichiro Hashiba, Jun'ichi Yokoyama
We construct a model explaining dark matter, baryon asymmetry and reheating in quintessential inflation model. Three generations of right-handed neutrinos having hierarchical masse…
An analytic evaluation of gravitational particle production of fermions via Stokes phenomenon
Soichiro Hashiba, Siyang Ling, Andrew J. Long
The phenomenon of gravitational particle production can take place for quantum fields in curved spacetime. The abundance and energy spectrum of gravitationally produced particles i…
Gauge Field Production and Schwinger Reheating in Runaway Axion Inflation
Soichiro Hashiba, Kohei Kamada, Hiromasa Nakatsuka
In a class of (pseudoscalar) inflation, inflationary phase is followed by a kination phase, where the Universe is dominated by the kinetic energy of the inflaton that runs away in…
Stokes phenomenon and gravitational particle production -- How to evaluate it in practice
Soichiro Hashiba, Yusuke Yamada
We revisit gravitational particle production from the Stokes phenomenon viewpoint, which helps us make a systematic way to understand asymptotic behavior of mode functions in time-…
Artifact-less Coded Aperture Imaging in the X-ray Band with Multiple Different Random Patterns
Tomoaki Kasuga, Hirokazu Odaka, Kosuke Hatauchi +7
The coded aperture imaging technique is a useful method of X-ray imaging in observational astrophysics. However, the presence of imaging noise or so-called artifacts in a decoded i…
Particle production induced by vacuum decay in real time dynamics
Soichiro Hashiba, Yusuke Yamada, Jun'ichi Yokoyama
We discuss particle production associated with vacuum decay, which changes the mass of a scalar field coupled to a background field which induces the decay. By utilizing the Stokes…
Dark matter and baryon-number generation in quintessential inflation via hierarchical right-handed neutrinos
Soichiro Hashiba, Jun'ichi Yokoyama
Incorporating three generations of right-handed Majorana neutrinos to quintessential inflation, we construct a model which simultaneously explains inflation, dark energy, dark matt…
Gravitational particle creation for dark matter and reheating
Soichiro Hashiba, Jun'ichi Yokoyama
The purely gravitational dark matter (PGDM) which interacts with the standard model particles only by gravitational interaction has recently been discussed. Due to its feeble inter…
Gravitational reheating through conformally coupled superheavy scalar particles
Soichiro Hashiba, Jun'ichi Yokoyama
We calculate the number density and the energy density of a massive scalar particle conformally coupled to gravity produced by gravitational particle creation in the case the kinat…