5 papers
Evolution of Black Holes in Brans-Dicke Cosmology
Nobuyuki Sakai, John D. Barrow
We consider a modified ``Swiss cheese'' model in the Brans-Dicke theory, and discuss the evolution of black holes in the expanding universe. We define the black hole radius by the…
Topological Defect Inflation
Nobuyuki Sakai
We address some issues of topological defect inflation. (1) We clarify the causal structure of an inflating magnetic monopole. The spacetime diagram shows explicitly that this mode…
Production of Global Monopoles through the Nucleation of Bubbles
Yoonbai Kim, Kei-ichi Maeda, Nobuyuki Sakai
First-order cosmological phase transitions are considered in the models with an -symmetric scalar field, in the high temperature limit. It is shown that a global monopole can…
Solitonic Island in the Bubble
Yoonbai Kim, Kei-ichi Maeda, Nobuyuki Sakai
We review how the continuous symmetry can support a soliton inside a high-temperature bubble at the time of its nucleation. This solitonic island in disoriented phase remains stabl…
Bubbles with an O(3) Symmetric Scalar Field in Curved Spacetime
Nobuyuki Sakai, Yoonbai Kim, Kei-ichi Maeda
We study the first-order phase transition in a model of scalar field with symmetry coupled to gravity, and, in high temperature limit, discuss the existence of new bubble so…