4 papers
Fluctuations of the Gravitational Constant Induced by Primordial Bubbles
Nobuyuki Sakai
We consider the classical fluctuations of the gravitational constant generated by bubbles in the inflationary universe. For extended inflation, we demonstrate numerically how and h…
Dynamics of Gravitating Magnetic Monopoles
Nobuyuki Sakai
According to previous work on magnetic monopoles, static regular solutions are nonexistent if the vacuum expectation value of the Higgs field is larger than a critical value $η…
Dynamics of Topological Defects and Inflation
Nobuyuki Sakai, Hisa-aki Shinkai, Takashi Tachizawa +1
We study the dynamics of topological defects in the context of ``topological inflation" proposed by Vilenkin and Linde independently. Analysing the time evolution of planar domain…
Junction Conditions of Friedmann-Robertson-Walker Space-Times
Nobuyuki Sakai, Kei-ichi Maeda
We complete a classification of junctions of two Friedmann-Robertson-Walker space-times bounded by a spherical thin wall. Our analysis covers super-horizon bubbles and thus complem…