Kiyoshi Shiraishi

Classical and Quantum Cosmology of Multigravity (2010)

We compute long-range forces up to next-leading order in the Einstein-Maxwell-dilaton system. To this end, we use the perturbative technique, because it is the most rigid way and could be extended to...

Hanada, Teruki, Kobayashi, Koichiro, Shinoda, Kazuhiko, Shiraishi, Kiyoshi

Recently, a multigraviton theory on a simple closed circuit graph corresponding to the discretization of $S^1$ compactification of the Kaluza-Klein (KK) theory has been considered. In the present...

Boson Stars under Deconstruction (2010)

Cancellation of long-range forces in Einstein-Maxwell-dilaton system (2009)

We study solutions for boson stars in multiscalar theory. We start with simple models with N scalar theories. Our purpose is to study the models in which the mass matrix of scalars and the scalar...

Kan, Nahomi, Kobayashi, Koichiro, Hanada, Teruki, Shiraishi, Kiyoshi

We examine cancellation of long-range forces in Einstein-Maxwell-Dilatonic system. Several conditions of the equilibrium of two charged masses in general relativity is found by many authors. These...

Cosmology of multigravity (2009)

Hanada, Teruki, Shinoda, Kazuhiko, Shiraishi, Kiyoshi

We have constructed a nonlinear multi-graviton theory. An application of this theory to cosmology is discussed. We found that scale factors in a solution for this theory repeat acceleration and...

Emergent Einstein Universe under Deconstruction (2009)

Vortices and Superfields on a Graph (2009)

We study self-consistent static solutions for an Einstein universe in a graph-based induced gravity. The one-loop quantum action is computed at finite temperature. In particular, we demonstrate...

Kan, Nahomi, Kobayashi, Koichiro, Shiraishi, Kiyoshi

We extend the dimensional deconstruction by utilizing the knowledge of graph theory. In the dimensional deconstruction, one uses the moose diagram to exhibit the structure of the `theory space'. We...

Multi-graviton theory in vierbein formalism (2008)

Hanada, Teruki, Shinoda, Kazuhiko, Shiraishi, Kiyoshi

Recently, multi-graviton theory on a simple closed circuit graph corresponding to the $S^1$ compactification of the Kaluza-Klein (KK) theory has been considered. In the present paper, we extend this...

Induced Gravity in Deconstructed Space at Finite Temperature -- Self-consistent Einstein Universe (2008)

Low-Energy Interaction of a Cosmic String and an Extreme Dilatonic Black Hole (2007)

We study self-consistent cosmological solutions for an Einstein Universe in a graph-based induced gravity model. The graph-based field theory has been proposed by the present authors to generalize...

Dilatonic Black Hole, Kiyoshi Shiraishi

The interaction of a cosmic string and a maximally charged dilatonic black hole is studied in the low-velocity limit. In particular, the string-black hole scattering at a low velocity is...

Finite density effects in Hosotani mechanism and a vacuum gauge ball (2004)

Cho, Yoshinori, Shiraishi, Kiyoshi

We consider the finite density effects of the fermion with U(1) gauge symmetry in Hosotani mechanism. We construct a vacuum gauge ball, a new kind of non-topological soliton, and investigate their...

Divergences in QED on a Graph (2004)

One-loop effective potential for the vacuum gauge field in $M_3\times S^3 \times S^1$ space-times (2004)

We consider a model of quantum electrodynamics (QED) on a graph. The one-loop divergences in the model are investigated by use of the background field method.

Cho, Yoshinori, Shiraishi, Kiyoshi

We calculate the effective potential for the vacuum gauge field from the one-loop matter effect in $M_3\times S^3\times S^1$ space-time. This background geometry is motivated from the recent studies...

Induced Gravity from Theory Space (2003)

One-loop finite potential for N-2 scalars from N quantum fields (2003)

The mass spectrum of a model constructed in a theory space is expressed by eigenvalues of the Laplacian on the graph structure of the theory space. The nature of the one-loop UV divergence in the...

Cho, Yoshinori, Kan, Nahomi, Sakamoto, Kenji, Shiraishi, Kiyoshi

We study the one-loop effective potential induced from quantum fluctuation of a finite number of fields. A series expansion in terms of the modified Bessel functions is useful to evaluate the...

Compactification in deconstructed gauge theory with topologically non-trivial link fields (2003)

Cho, Yoshinori, Kan, Nahomi, Shiraishi, Kiyoshi

We investigate the mass spectrum of a scalar field in a world with latticized and circular continuum space where background fields takes a topological configuration. We find that the mass spectrum is...

Non-topological soliton in three-dimensional supergravity (2003)

Cho, Yoshinori, Sakamoto, Kenji, Shiraishi, Kiyoshi

We construct numerical solutions for non-topological solitons in three-dimensional U(1)-gauged ${\cal N}=2$ supergravity. We find the region of the solutions showing with the BTZ mass, the angular...

Quantum Scattering in Two Black Hole Moduli Space (2003)

Multi-graviton theory, a latticized dimension, and the cosmological constant (2002)

We discuss the quantum scattering process in the moduli space consisting of two maximally charged dilaton black holes. The black hole moduli space geometry has different structures for arbitrary...

Shape of Deconstruction (2002)

Beginning with the Pauli-Fierz theory, we construct a model for multi-graviton theory. Couplings between gravitons belonging to nearest-neighbor ``theory spaces'' lead to a discrete mass spectrum....

Shiraishi, Kiyoshi, Sakamoto, Kenji, Kan, Nahomi

We construct a six-dimensional Maxwell theory using a latticized extra space, the continuum limit of which is a shifted torus recently discussed by Dienes. This toy model exhibits the correspondence...

Deconstructing Scalar QED at Zero and Finite Temperature (2002)

Kan, Nahomi, Sakamoto, Kenji, Shiraishi, Kiyoshi

We calculate the effective potential for the WLPNGB in a world with a circular latticized extra dimension. The mass of the WLPNGB is calculated from the one-loop quantum effect of scalar fields at...

Bulk Fermion Stars with New Dimensions (2002)

Noncommutative gravity in three dimensions coupled to spinning sources (2002)

Many efforts have been devoted to the studies of the phenomenology in particle physics with extra dimensions. We propose degenerate fermion stars with extra dimensions and study what features...

Shiraishi, Kiyoshi, Sakamoto, Kenji, Kan, Nahomi

Noncommutative gravity in three dimensions with vanishing cosmological constant is examined. We find a solution which describes a spacetime in the presence of a torsional source. We estimate the...

Conformal Quantum Mechanics in Two Black Hole Moduli Space (2002)

Noncommutative gravity in three dimensions coupled to point-like sources (2002)

We discuss quantum mechanics in the moduli space consisting of two maximally charged dilaton black holes. The quantum mechanics of the two black hole system is similar to the one of DFF model, and...

Scattering in Two Black Hole Moduli Space (2002)

Noncommutative gravity in three dimensions with no cosmological constant is reviewed. We find a solution which describes the presence of a torsional source.

Equation of state for a classical gas of BPS black holes (2001)

In this work, we discuss the quantum mechanics on the moduli space consisting of two maximally charged dilaton black holes. We study the quantum effects resulting from the different structure of the...

Kan, Nahomi, Maki, Takuya, Shiraishi, Kiyoshi

A point particle treatment to the statistical mechanics of BPS black holes in Einstein-Maxwell-dilaton theory is developed. Because of the absence of the static potential, the canonical partition...

Effective field theory of slowly-moving "extreme black holes" (2000)

Degura, Yoshitaka, Shiraishi, Kiyoshi

We consider the non-relativistic effective field theory of ``extreme black holes'' in the Einstein-Maxwell-dilaton theory with an arbitrary dilaton coupling. We investigate finite-temperature...

Extremely charged static perfect fluid distributions with dilaton in curved spacetimes (2000)

Cho, Yoshinori, Degura, Yoshitaka, Shiraishi, Kiyoshi

We examine charged static perfect fluid distributions with a dilaton field in the frame-work of general relativity. We consider the case that the Einstein equations reduce to a non-linear version of...

Fermion Stars with an Extra Dimension (2000)

Finite Temperature Field Theory of "Extreme Black Holes" (2000)

Many efforts have been devoted to the studies of the phenomenology in particle physics with extra dimensions. We propose the degenerate fermion star in the five dimensions, and study what effects...

Degura, Yoshitaka, Shiraishi, Kiyoshi

We treat the model which describes "extreme black holes" moving slowly. We derive an effective lagrangian in the low energy for this model and then investigate a statistical behavior of "extreme...

Multi-centered Solutions with a (very special) Warped Compactification (1999)

Ooho, Mitsuru, Shiraishi, Kiyoshi

We find an exact solution for multi-black strings in the brane world with warped compactification.

Rotating Boson Star with Large Self-interaction in (2+1) dimensions (1999)

Exact Solutions for Boson-Fermion Stars in (2+1) dimensions (1998)

Solutions for rotating boson stars in (2+1) dimensional gravity with a negative cosmological constant are obtained numerically. The mass, particle number, and radius of the (2+1) dimensional rotating...

Black Holes with Scalar Hair in (2+1) dimensions (1998)

We solve Einstein equations coupled to a complex scalar field with infinitely large self-interaction, degenerate fermions, and a negative cosmological constant in $(2+1)$ dimensions. Exact solutions...

Degura, Yoshitaka, Sakamoto, Kenji, Shiraishi, Kiyoshi

Nonrotating and rotating black hole soltuions in (2+1) dimensions are studied in a model including a real scalar field with a simple potential coupled to gravity.

Boson Stars with Large Self-interaction in (2+1) dimensions: an Exact Solution (1998)

Low-Energy Interaction of a Cosmic String and an Extreme Dilatonic Black Hole (1995)

An exact solution for a nonrotating boson star in (2+1) dimensional gravity with a negative cosmological constant is found. The relations among mass, particle number, and radius of the (2+1)...

Extreme Dilatonic Black Holes on a Torus (1995)

The interaction of a cosmic string and a maximally charged dilatonic black hole is studied in the low-velocity limit. In particular, the string-black hole scattering at a low velocity is investigated.

Statistical Mechanics of Charged Particles in Einstein-Maxwell-Scalar Theory (1995)

The interaction of maximally-charged dilatonic black holes on $R^{4}\times T^{d}$ is studied in the low-velocity limit. In particular, the scattering of two black holes on $R^{4}\times S^{1}$ is...

Shiraishi, Kiyoshi, Maki, Takuya

We consider an $N$-body system of charged particle coupled to gravitational, electromagnetic, and scalar fields. The metric on moduli space for the system can be considered if a relation among the...

Many-body systems in Einstein-Maxwell-Dilaton theory (1995)