165 citations · 2.5k across the 85 of their papers we have counts for
12 papers · 1 filter
4-volume cutoff measure of the multiverse
Alexander Vilenkin, Masaki Yamada
Predictions in an eternally inflating multiverse are meaningless unless we specify the probability measure. The scale-factor cutoff is perhaps the simplest and most successful meas…
A more attractive scheme for radion stabilization and supercooled phase transition
Kohei Fujikura, Yuichiro Nakai, Masaki Yamada
We propose a new radion stabilization mechanism in the Randall-Sundrum spacetime, introducing a bulk gauge field which confines at a TeV scale. It turns out that the ra…
Fundamental Forces and Scalar Field Dynamics in the Early Universe
Alexander Kusenko, Volodymyr Takhistov, Masaki Yamada +1
Scalar weak gravity conjectures (SWGCs) attempt to pinpoint the ranges of couplings consistent with a fundamental theory of all interactions. We identify a generic dynamical conseq…
Unification for the Darkly Charged Dark Matter
Ayuki Kamada, Masaki Yamada, Tsutomu T. Yanagida
We provide a simple UV theory for a Dirac dark matter with a massless Abelian gauge boson. We introduce a single fermion transforming as the representation in the SO(10)$…
Cosmic perturbations, baryon asymmetry and dark matter from the minimal supersymmetric standard model
Keisuke Harigaya, Masaki Yamada
Scalar fields in the minimal supersymmetric standard model may have large field values during inflation. Because of approximate global symmetry, it is plausible that the phase dire…
Charged black holes in non-linear Q-clouds with O(3) symmetry
Jeong-Pyong Hong, Motoo Suzuki, Masaki Yamada
We construct charged soliton solutions around spherical charged black holes with no angular momentum in asymptotically flat spacetime. These solutions are non-linear generalization…
Unification of the Standard Model and Dark Matter Sectors in [SU(5)U(1)]
Ayuki Kamada, Masaki Yamada, Tsutomu T. Yanagida
A simple model of dark matter contains a light Dirac field charged under a hidden U(1) gauge symmetry. When a chiral matter content in a strong dynamics satisfies the t'Hooft anoma…
Light majoron cold dark matter from topological defects and the formation of boson stars
Mario Reig, José W. F. Valle, Masaki Yamada
We show that for a relatively light majoron ( eV) non-thermal production from topological defects is an efficient production mechanism. Taking the type I seesaw as benchm…
Anthropic Bound on Dark Radiation and its Implications for Reheating
Fuminobu Takahashi, Masaki Yamada
We derive an anthropic bound on the extra neutrino species, , based on the observation that a positive suppresses the growth of matter fluctuations due…
Vacuum Decay in Real Time and Imaginary Time Formalisms
Mark P. Hertzberg, Masaki Yamada
We analyze vacuum tunneling in quantum field theory in a general formalism by using the Wigner representation. In the standard instanton formalism, one usually approximates the ini…
Constraints on non-minimal coupling from quantum cosmology
Shao-Jiang Wang, Masaki Yamada, Alexander Vilenkin
Quantum cosmology is investigated in a de Sitter minisuperspace model with a quantized scalar field non-minimally coupled to curvature. Quantum states of the scalar field must sati…
Dark Matter Production during the Thermalization Era
Keisuke Harigaya, Kyohei Mukaida, Masaki Yamada
We revisit the non-thermal dark matter (DM) production during the thermalization and reheating era after inflation. The decay of inflaton produces high-energy particles that are th…