Nonlinear superhorizon perturbations of non-canonical scalar field (2008)
Takamizu, Yu-ichi, Mukohyama, Shinji
We develop a theory of non-linear cosmological perturbations at superhorizon scales for a scalar field with a Lagrangian of the form $P(X,\phi)$, where $X=-\partial^{\mu}\phi\partial_{\mu}\phi$ and...
Bulk scalar emission from a rotating black hole pierced by a tense brane (2007)
Kobayashi, Tsutomu, Nozawa, Masato, Takamizu, Yu-ichi
We study the emission of scalar fields into the bulk from a six-dimensional rotating black hole pierced by a 3-brane. We determine the angular eigenvalues in the presence of finite brane tension by...
Hybrid compactifications and brane gravity in six dimensions (2007)
Kobayashi, Tsutomu, Takamizu, Yu-ichi
We consider a six-dimensional axisymmetric Einstein-Maxwell model of warped braneworlds. The bulk is bounded by two branes, one of which is a conical 3-brane and the other is a 4-brane wrapped around...
Dynamics of colliding branes and black brane production (2007)
Takamizu, Yu-ichi, Kudoh, Hideaki, Maeda, Kei-ichi
We study the dynamics of colliding domain walls including self-gravity. The initial data is set up by applying a BPS domain wall in five-dimensional supergravity, and we evolve the system determining...
Fermions on Colliding Branes (2006)
Gibbons, Gary, Maeda, Kei-ichi, Takamizu, Yu-ichi
We study the behaviour of five-dimensional fermions localized on branes, which we describe by domain walls, when two parallel branes collide in a five-dimensional Minkowski background spacetime. We...
Thermal Equilibrium of String Gas in Hagedorn Universe (2006)
Takamizu, Yu-ichi, Kudoh, Hideaki
The thermal equilibrium of string gas is necessary to activate the Brandenberger-Vafa mechanism, which makes our observed 4-dimensional universe enlarge. Nevertheless, the thermal equilibrium is not...
Collision of Domain Walls in asymptotically Anti de Sitter spacetime (2006)
Takamizu, Yu-ichi, Maeda, Kei-ichi
We study collision of two domain walls in 5-dimensional asymptotically Anti de Sitter spacetime. This may provide the reheating mechanism of an ekpyrotic (or cyclic) brane universe, in which two BPS...
Collision of Domain Walls and Reheating of the Brane Universe (2004)
Takamizu, Yu-ichi, Maeda, Kei-ichi
We study a particle production at the collision of two domain walls in 5-dimensional Minkowski spacetime. This may provide the reheating mechanism of an ekpyrotic (or cyclic) brane universe, in which...