3 papers
astro-ph.CO2026
Reheating with Thermal Dissipation and Primordial Gravitational Waves
Kazuma Minami, Kyohei Mukaida, Kazunori Nakayama
In order for an inflationary universe to evolve into a hot universe, a process known as reheating is required. However, the precise mechanism of reheating remains unknown. We show…
hep-ph2026
Gravitational Decays of Secluded Scalars and Graviton Dark Radiation
Kazunori Nakayama, Fuminobu Takahashi, Juntaro Wada
We discuss graviton dark radiation produced by the decay of a secluded scalar field that couples to the Standard Model (SM) only through gravity. Such scalar fields are long-lived,…
quant-ph2025
Multilayered Aspects of Casimir Energy
Kyohei Mukaida, Hideo Iizuka, Kazunori Nakayama
We give a robust formulation to calculate the Casimir energy and Casimir force for plane-parallel multilayer setups with general dielectric constants. We derive recursion relations…