6 papers
Domain-wall Quintessence
Nobufusa Kobayashi, Yuichiro Tada, Fuminobu Takahashi +1
We investigate a dark energy model driven by a planar domain-wall-like structure with a thickness comparable to, or larger than, the current Hubble radius, focusing on its intrinsi…
Gravitational wave emission from nonspherical collapse in an early matter-dominated era using N-body simulations
Albert EscrivÃ, Tomohiro Harada, Kazunori Kohri +2
We study the dynamics of the collapse of a nonspherical overdense patch during an early matter-dominated era and the associated production of gravitational waves (GWs) using a semi…
Quintessence with tachyonic resonance and late-time cosmic-microwave-background and gravitational-wave signals
Shun Yoshioka, Kiyotomo Ichiki, Yuichiro Tada +1
Combinations of recent cosmological observations, including Dark Energy Spectroscopic Instrument (DESI), show hints of a dynamical nature for dark energy. While the data suggest th…
Semianalytic calculation of the gravitational wave spectrum induced by curvature perturbations
Takahiro Terada
The stochastic gravitational wave (GW) background is secondarily and inevitably induced by the primordial curvature perturbations beyond the first order of the cosmological perturb…
The poltergeist mechanism -- Enhancement of scalar-induced gravitational waves with early matter-dominated era
Keisuke Inomata, Kazunori Kohri, Takahiro Terada
Gravitational waves induced by primordial density perturbations provide a powerful probe of the Universe's thermal history, which may include an early matter-dominated (eMD) era pr…
Anisotropic Gravitational Waves from Anisotropic Axion Rotation
Arushi Bodas, Keisuke Harigaya, Keisuke Inomata +2
Gravitational waves (GWs) provide a powerful probe of the early universe due to their ability to free-stream across cosmic history. We study GW production in a compelling scenario…