no code implementations • 20 Nov 2020 • Yasutaka Koga, Takahisa Igata, Keisuke Nakashi
As we show finally, the pseudopotential arises due to the separability of the null geodesic equation, and the separability comes from the existence of a Killing tensor in the spacetime.
General Relativity and Quantum Cosmology
no code implementations • 2 Nov 2020 • Tomohiro Harada, Chul-Moon Yoo, Kazunori Kohri, Yasutaka Koga, Takeru Monobe
The standard deviation of the initial values of the nondimensional Kerr parameter $a_{*}$ of primordial black holes (PBHs) formed in the radiation-dominated phase of the universe is estimated to the first order of perturbation for the narrow power spectrum.
Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology
