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Reheating process in the inflationary model with the baryogenesis scenario
Hyun Jeong, Kohei Kamada, Alexei A. Starobinsky +1
Post-inflationary evolution and (re)heating of the viable inflationary model, the one, is made more realistic by including the leptogenesis scenario into it. For this purpose…
Baryogenesis from sphaleron decoupling
Muzi Hong, Kohei Kamada, Jun'ichi Yokoyama
The electroweak sphaleron process breaks the baryon number conservation within the realms of the Standard Model of particle physics (SM). Recently, it is pointed out that its decou…
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…
Occurrence of Tachyonic Preheating in the Mixed Higgs- Model
Minxi He, Ryusuke Jinno, Kohei Kamada +2
It has recently been suggested that at the post-inflationary stage of the mixed Higgs- model of inflation efficient particle production can arise from the tachyonic instabilit…
Gravitational leptogenesis with kination and gravitational reheating
Kohei Kamada, Jun'ya Kume, Yusuke Yamada +1
We revisit the gravitational leptogenesis scenario in which the inflaton is coupled to gravity by the Chern-Simons term and the lepton asymmetry is generated through the gravitatio…
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…
On the violent preheating in the mixed Higgs- inflationary model
Minxi He, Ryusuke Jinno, Kohei Kamada +3
It has been argued that the mixed Higgs- model acts as the UV extension of the Higgs inflation, pushing up its cut-off scale in the vacuum close up to the Planck scale. In thi…
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…
Long-term dynamics of cosmological axion strings
Masahiro Kawasaki, Toyokazu Sekiguchi, Masahide Yamaguchi +1
We present results of new field-theoretic simulation of cosmological axion strings, which are eight times longer than previous ones. We have upgraded our simulation of physical str…
Possible resolution of the domain wall problem in the NMSSM
Anupam Mazumdar, Ken'ichi Saikawa, Masahide Yamaguchi +1
We discuss a possibility that the domain wall problem in the next-to-minimal supersymmetric standard model is alleviated without introducing a small explicit breaking term by…
Effects of thermal fluctuations on thermal inflation
Takashi Hiramatsu, Yuhei Miyamoto, Jun'ichi Yokoyama
The mechanism of thermal inflation, a relatively short period of accelerated expansion after primordial inflation, is a desirable ingredient for a certain class of particle physics…
Reheating processes after Starobinsky inflation in old-minimal supergravity
Takahiro Terada, Yuki Watanabe, Yusuke Yamada +1
We study reheating processes and its cosmological consequences in the Starobinsky model embedded in the old-minimal supergravity. First, we consider minimal coupling between the gr…
Graceful exit from Higgs G-inflation
Kohei Kamada, Tsutomu Kobayashi, Taro Kunimitsu +2
Higgs G-inflation is a Higgs inflation model with a generalized Galileon term added to the standard model Higgs field, which realizes inflation compatible with observations. Recent…
Langevin description of gauged scalar fields in a thermal bath
Yuhei Miyamoto, Hayato Motohashi, Teruaki Suyama +1
We study the dynamics of the oscillating gauged scalar field in a thermal bath. A Langevin type equation of motion of the scalar field, which contains both dissipation and fluctuat…
Higgs condensation as an unwanted curvaton
Taro Kunimitsu, Jun'ichi Yokoyama
During inflation in the early universe, the Higgs field continuously acquires long-wave quantum fluctuations. They accumulate to yield a non-vanishing value with an exponentially l…
Generalized Higgs inflation
Kohei Kamada, Tsutomu Kobayashi, Tomo Takahashi +2
We study Higgs inflation in the context of generalized G-inflation, i.e. the most general single-field inflation model with second-order field equations. The four variants of Higgs…
Phase transition and monopole production in supergravity inflation
Kohei Kamada, Kazunori Nakayama, Jun'ichi Yokoyama
In F-term supergravity inflation models, scalar fields other than the inflaton generically receive a Hubble induced mass, which may restore gauge symmetries during inflation and ph…
Improved estimation of radiated axions from cosmological axionic strings
Takashi Hiramatsu, Masahiro Kawasaki, Toyokazu Sekiguchi +2
Cosmological evolution of axionic string network is analyzed in terms of field-theoretic simulations in a box of 512^3 grids, which are the largest ever, using a new and more effic…
Affleck Dine leptogenesis via multiple flat directions
Kohei Kamada, Jun'ichi Yokoyama
We investigate the Affleck-Dine mechanism when multiple flat directions have large values simultaneously. We consider in detail the case when both and flat directio…
Higgsflation at the GUT scale in a Higgsless Universe
Nemanja Kaloper, Lorenzo Sorbo, Jun'ichi Yokoyama
We revisit inflation in induced gravity. Our focus is on models where the low scale Planck mass is completely determined by the breaking of the scaling symmetry in the field theory…
Space laser interferometers can determine the thermal history of the early Universe
Kazunori Nakayama, Shun Saito, Yudai Suwa +1
It is shown that space-based gravitational wave detectors such as DECIGO and/or Big Bang Observer (BBO) will provide us with invaluable information on the cosmic thermal history af…
Lepton asymmetry in the primordial gravitational wave spectrum
Kiyotomo Ichiki, Masahide Yamaguchi, Jun'Ichi Yokoyama
Effects of neutrino free streaming is evaluated on the primordial spectrum of gravitational radiation taking both neutrino chemical potential and masses into account. The former or…
Time variation of proton-electron mass ratio and fine structure constant with runaway dilaton
Takeshi Chiba, Tatsuo Kobayashi, Masahide Yamaguchi +1
Recent astrophysical observations indicate that the proton-electron mass ratio and the fine structure constant have gone through nontrivial time evolution. We discuss their time va…
Power Spectrum of the Density Perturbations From Smooth Hybrid New Inflation Model
Masahiro Kawasaki, Tsutomu Takayama, Masahide Yamaguchi +1
We numerically investigate density perturbations generated in the smooth hybrid new inflation model, a kind of double inflation model that is designed to reproduce the running spec…