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Density fluctuations in one-field inflation
Masahide Yamaguchi, Jun'ichi Yokoyama
Any one-field inflation is actually realized in a multifield configuration because the inflaton must have couplings with other fields to reheat the universe and is coupled to all o…
Can oscillating scalar fields decay into particles with a large thermal mass?
Jun'ichi Yokoyama
We calculate the dissipation rate of a coherently oscillating scalar field in a thermal environment using nonequilibrium quantum field theory and apply it to the reheating stage af…
Hiding cosmic strings in supergravity D-term inflation
Osamu Seto, Jun'ichi Yokoyama
The influence of higher-order terms in the Kähler potential of the supergravity D-term inflation model on the density perturbation is studied. We show that these terms can make the…
Constraining Cosmological Parameters by the Cosmic Inversion Method
Noriyuki Kogo, Misao Sasaki, Jun'ichi Yokoyama
We investigate the question of how tightly we can constrain the cosmological parameters by using the ``cosmic inversion'' method in which we directly reconstruct the power spectrum…
Neutralino Dark Matter from Heavy Gravitino Decay
Kazunori Kohri, Masahiro Yamaguchi, Jun'ichi Yokoyama
We propose a new scenario of non-thermal production of neutralino cold dark matter, in which the overproduction problem of lightest supersymmetric particles (LSPs) in the standard…