Primordial magnetic field from non-inflationary cosmic expansion in Horava-Lifshitz gravity (2009)
Maeda, Satoshi, Mukohyama, Shinji, Shiromizu, Tetsuya
The origin of large-scale magnetic field in the universe is one of the greatest mysteries in modern cosmology. We present a new mechanism for generation of large-scale magnetic field, based on the...
On asymptotic structure at null infinity in five dimensions (2009)
Tanabe, Kentaro, Tanahashi, Norihiro, Shiromizu, Tetsuya
We discuss the asymptotic structure of null infinity in five dimensional space-time. Since it is known that the conformal infinity is not useful for odd higher dimensions, we shall employ the...
The Riemannian Penrose inequality and a virtual gravitational collapse (2009)
Ohashi, Seiju, Shiromizu, Tetsuya, Yamada, Sumio
We reinterpret the proof of the Riemannian Penrose inequality by H. Bray. The modified argument turns out to have a nice feature so that the flow of Riemannian metrics appearing Bray's proof gives a...
Asymptotic flatness at spatial infinity in higher dimensions (2009)
Tanabe, Kentaro, Tanahashi, Norihiro, Shiromizu, Tetsuya
A definition of asymptotic flatness at spatial infinity in $d$ dimensions ($d\geq 4$) is given using the conformal completion approach. Then we discuss asymptotic symmetry and conserved quantities....
Maeda, Satoshi, Kitagawa, Satoshi, Kobayashi, Tsutomu, Shiromizu, Tetsuya
We explore the possibility of generating large-scale magnetic fields from second-order cosmological perturbations during the pre-recombination era. The key process for this is Thomson scattering...
Curvature corrections to the low energy effective theory in 6D regularized braneworlds (2008)
Kobayashi, Tsutomu, Shiromizu, Tetsuya, De Rham, Claudia
We study the effective gravitational theory on a brane in a six-dimensional Einstein-Maxwell model of flux compactification, regularizing a conical defect as a codimension-one brane. We employ the...
Low energy effective theory on a regularized brane in 6D gauged chiral supergravity (2007)
Arroja, Frederico, Kobayashi, Tsutomu, Koyama, Kazuya, Shiromizu, Tetsuya
We derive the low energy effective theory on a brane in six-dimensional chiral supergravity. The conical 3-brane singularities are resolved by introducing cylindrical codimension one 4-branes whose...
Low energy effective theory on a regularized brane in six-dimensional flux compactifications (2007)
Fujii, Shunsuke, Kobayashi, Tsutomu, Shiromizu, Tetsuya
Conical brane singularities in six-dimensional flux compactification models can be resolved by introducing cylindrical codimension-one branes with regular caps instead of 3-branes (a la Kaluza-Klein...
Collision of high-energy closed strings: Formation of a ring-like apparent horizon (2007)
Yoshino, Hirotaka, Shiromizu, Tetsuya
We study collisions of two high-energy closed strings in the framework of $D$-dimensional general relativity. The model of a high-energy closed string is introduced as a {/it pp}-wave generated by a...
Shirata, Akihito, Suto, Yasushi, Hikage, Chiaki, Shiromizu, Tetsuya, Yoshida, Naoki
We explore observational constraints on possible deviations from Newtonian gravity by means of large-scale clustering of galaxies. We measure the power spectrum and the bispectrum of Sloan Digital...
Cosmological magnetic fields from nonlinear effects (2007)
Kobayashi, Tsutomu, Maartens, Roy, Shiromizu, Tetsuya, Takahashi, Keitaro
In the standard cosmological model, magnetic fields and vorticity are generated during the radiation era via second-order density perturbations. In order to clarify the complicated physics of this...
Yoshino, Hirotaka, Shiromizu, Tetsuya, Shibata, Masaru
Scenarios of large extra dimensions have enhanced the importance for the study of black holes in higher dimensions. In this paper, we analyze an axisymmetric system of two black holes. Specifically,...
Positive energy theorem implies constraints on static steller models (2006)
Shiromizu, Tetsuya, Yoshino, Hirotaka
Using the positive energy theorem, we derive some constraints on static steller models in asymptotically flat spacetimes in a general setting without imposing spherical symmetry. We show that there...
Low energy effective gravitational equations on a Gauss-Bonnet brane (2006)
Kobayashi, Tsutomu, Shiromizu, Tetsuya, Deruelle, Nathalie
We present effective gravitational equations at low energies in a $Z_2$-symmetric braneworld with the Gauss-Bonnet term. Our derivation is based on the geometrical projection approach, and we solve...
Holographic entanglement entropy of de Sitter braneworld (2006)
Iwashita, Yukinori, Kobayashi, Tsutomu, Shiromizu, Tetsuya, Yoshino, Hirotaka
We study the holographic representation of the entanglement entropy, recently proposed by Ryu and Takayanagi, in a braneworld context. The holographic entanglement entropy of a de Sitter brane...
On existence of matter outside a static black hole (2006)
Shiromizu, Tetsuya, Yamada, Sumio, Yoshino, Hirotaka
It is expected that matter composed of a perfect fluid cannot be at rest outside of a black hole if the spacetime is asymptotically flat and static (non-rotating). However, there has not been a...
Weaker Gravity at Submillimetre Scales in Braneworld Models (2006)
De Rham, Claudia, Shiromizu, Tetsuya, Tolley, Andrew J.
Braneworld models typically predict gravity to grow stronger at short distances. In this paper, we consider braneworlds with two types of additional curvature couplings, a Gauss-Bonnet term in the...
High-energy effective theory for orbifold branes (2006)
Shiromizu, Tetsuya, Fujii, Shunsuke, De Rham, Claudia, Yoshino, Hirotaka
We derive an effective theory on the orbifold branes of the Randall-Sundrum 1 (RS1) braneworld scenario in the presence of a bulk brane. We concentrate on the regime where the three branes are close...
High-energy effective theory for a bulk brane (2005)
De Rham, Claudia, Fujii, Shunsuke, Shiromizu, Tetsuya, Yoshino, Hirotaka
We derive an effective theory describing the physics of a bulk brane in the context of the RS1 model. This theory goes beyond the usual low energy effective theory in that it describes the regime...
Yoshino, Hirotaka, Shiromizu, Tetsuya, Shibata, Masaru
Motivated by the TeV-scale gravity scenarios, we study gravitational radiation in the head-on collision of two black holes in higher dimensional spacetimes using a close-limit approximation. We...
Gravitational collapse disturbs the dS/CFT correspondence? (2005)
Iwashita, Yukinori, Yoshino, Hirotaka, Shiromizu, Tetsuya
We study the gravitational collapse in five-dimensional de Sitter (dS) spacetime and discuss the existence of the conformal boundaries at future timelike infinity from the perspective of the dS/CFT...
Baryon number violation due to brane dynamics (2005)
Uesugi, Tomoko, Fujii, Shunsuke, Shiromizu, Tetsuya
We derive the low energy effective theory for two brane system with bulk complex scalar fields. Then we find that higher order corrections to the effective equation for scalar fields on the brane...
Gravity is controlled by cosmological constant (2005)
Iwashita, Yukinori, Shiromizu, Tetsuya, Takahashi, Keitaro, Fujii, Shunsuke
We discuss a Randall-Sundrum-type two D-braneworld model in which D-branes possess different values of the tensions from those of the charges, and derive an effective gravitational equation on the...
Galaxy clustering constraints on deviations from Newtonian gravity at cosmological scales (2005)
Shirata, Akihito, Shiromizu, Tetsuya, Yoshida, Naoki, Suto, Yasushi
In spite of the growing observational evidence for dark matter and dark energy in the universe, their physical nature is largely unknown. In fact, several authors have proposed modifications of...
Positivity Bounds for the Y-ADM Mass Density (2004)
Kastor, David, Shiromizu, Tetsuya, Tomizawa, Shinya, Traschen, Jennie
Killing-Yano tensors are natural generalizations of Killing vectors to arbitrary rank anti-symmetric tensor fields. It was recently shown that Killing-Yano tensors lead to conserved gravitational...
Asymmetric D-braneworld (2004)
Takahashi, Keitaro, Shiromizu, Tetsuya
In recent papers on Randall-Sundrum D-braneworld model with Z_2 symmetry, it was shown that the effective gravity does not work as usual, that is, the gravity does not couple to the gauge field...
Gravity in Randall-Sundrum two D-brane model (2004)
Shiromizu, Tetsuya, Takahashi, Keitaro, Himemoto, Yoshiaki, Yamamoto, Shuto
We analyse Randall-Sundrum two D-brane model by linear perturbation and then consider the linearised gravity on the D-brane. The qualitative contribution from the Kaluza-Klein modes of gauge fields...
Kaluza-Klein bubble like structure and celestial sphere in inflationary universe (2004)
Shiromizu, Tetsuya, Tomizawa, Shinya, Uchida, Yuki, Mukohyama, Shinji
We consider five dimensional deSitter spacetimes with a deficit angle due to the presence of a closed 2-brane and identify one dimension as an extra dimension. From the four dimensional viewpoint we...
Twist of stationary black hole/ring in five dimensions (2004)
Tomizawa, Shinya, Uchida, Yuki, Shiromizu, Tetsuya
It is unlikely that uniqueness theorem holds for stationary black holes in higher dimensional spacetimes. However, we will examine the possibility that the higher multipole moments classify vacuum...
Randall-Sundrum two D-brane model (2004)
Shiromizu, Tetsuya, Himemoto, Yoshiaki, Takahashi, Keitaro
In Randall-Sundrum two D-brane system we derive the gravitational theory on the branes. It is turned out from the consistency that one D-brane has the negative tension brane under Randall-Sundrum...
Spacetime dynamics and baryogenesis in braneworld (2004)
Shiromizu, Tetsuya, Koyama, Kazuya
We point out that the effective theory for the Randall-Sundrum braneworld models with bulk fields contains the baryon number violation process depending on the spacetime dynamics. Combining to the...
Spatial infinity in higher dimensional spacetimes (2004)
Shiromizu, Tetsuya, Tomizawa, Shinya
Motivated by recent studies on the uniqueness or non-uniqueness of higher dimensional black hole spacetime, we investigate the asymptotic structure of spatial infinity in n-dimensional spacetimes($n...
Low energy effective action on a self-gravitating D-brane (2003)
Onda, Sumitada, Shiromizu, Tetsuya, Koyama, Kazuya, Hayakawa, Shoko
Recently the study of braneworld on the self-gravitating D-brane has been initiated and derived the gravitational equation on the brane by holographic and geometrical projection methods....
D-braneworld cosmology II: Higher order corrections (2003)
Uesugi, Tomoko, Shiromizu, Tetsuya, Torii, Takashi, Takahashi, Keitaro
We investigate braneworld cosmology based on the D-brane initiated in our previous paper. The brane is described by a Born-Infeld action and the gauge field is contained. The higher order corrections...
Kinematical bound in asymptotically translationally invariant spacetimes (2003)
Shiromizu, Tetsuya, Ida, Daisuke, Tomizawa, Shinya
We present positive energy theorems in asymptotically translationally invariant spacetimes which can be applicable to black strings and charged branes. We also address the bound property of the...
Cosmological constant and gravitational theory on D-brane (2003)
Shiromizu, Tetsuya, Koyama, Kazuya, Torii, Takashi
In a toy model we derive the gravitational equation on a self-gravitating curved D-brane. The effective theory on the brane is drastically changed from the ordinal Einstein equation. The net...
Can we live on a D-brane? -- Effective theory on a self-gravitating D-brane -- (2003)
Shiromizu, Tetsuya, Koyama, Kazuya, Onda, Sumitada, Torii, Takashi
We consider a D-brane coupled with gravity in type IIB supergravity on S^5 and derive the effective theory on the D-brane in two different ways, that is, holographic and geometrical projection...
Steep Inflation followed by Born-Infeld Reheating (2003)
Sami, M., Dadhich, N., Shiromizu, Tetsuya
We discuss a model in which high energy brane corrections allow a single scalar field to describe inflation at early epochs and quintessence at late times. The reheating mechanism in the model...
Shiromizu, Tetsuya, Torii, Takashi, Uesugi, Tomoko
We discuss D-braneworld cosmology, that is, the brane is described by the Born-Infeld action. Compared with the usual Randall-Sundrum braneworld cosmology where the brane action is the Nambu-Goto...
Effective theory for close limit of two branes (2002)
Shiromizu, Tetsuya, Koyama, Kazuya, Takahashi, Keitaro
We discuss the effective theory for the close limit of two branes in a covariant way. To do so we solve the five dimensional Einstein equation along the direction of the extra dimension. Using the...
Low energy effective theory for two branes system (2002)
Shiromizu, Tetsuya, Koyama, Kazuya
We derive the low energy effective theory for two branes system solving the bulk geometry formally in the covariant curvature formalism developed by Shiromizu, Maeda and Sasaki. As expected, the...
Cosmological constant, dilaton field and Freund-Rubin compactification (2002)
Torii, Takashi, Shiromizu, Tetsuya
We discuss the Freund-Rubin compactification with cosmological constant and the dilaton field, and examine the stability of the spacetimes at the low energy. The Minkowski or de Sitter spacetime can...
Uniqueness of (dilatonic) charged black holes and black p-branes in higher dimensions (2002)
Gibbons, Gary W., Ida, Daisuke, Shiromizu, Tetsuya
We prove the uniqueness of higher dimensional (dilatonic) charged black holes in static and asymptotically flat spacetimes for arbitrary vector-dilaton coupling constant. An application to the...
Uniqueness and non-uniqueness of static black holes in higher dimensions (2002)
Gibbons, Gary W., Ida, Daisuke, Shiromizu, Tetsuya
We prove a uniqueness theorem for asymptotically flat static charged dilaton black hole solutions in higher dimensional space-times. We also construct infinitely many non-asymptotically flat regular...
Uniqueness and non-uniqueness of static vacuum black holes in higher dimensions (2002)
Gibbons, Gary W., Ida, Daisuke, Shiromizu, Tetsuya
We prove the uniqueness theorem for asymptotically flat static vacuum black hole solutions in higher dimensional space-times. We also construct infinitely many non-asymptotically flat regular static...
Gravitational energy, dS/CFT correspondence and cosmic no-hair (2001)
Shiromizu, Tetsuya, Ida, Daisuke, Torii, Takashi
The gravitational energy is examined in asymptotically de Sitter space-times. The positivity will be shown for certain cases. The de Sitter/CFT(dS/CFT) correspondence recently proposed and cosmic...
Semiclassical instability of the brane-world: Randall-Sundrum bubbles (2001)
Ida, Daisuke, Shiromizu, Tetsuya, Ochiai, Hirotaka
We discuss the semiclassical instability of the Randall-Sundrum brane-world model against a creation of a kind of Kaluza-Klein bubble. An example describing such a bubble space-time is constructed...
Stability of $AdS_p x S^n x S^{q-n}$ Compactifications (2001)
Shiromizu, Tetsuya, Ida, Daisuke, Ochiai, Hirotaka, Torii, Takashi
We examine the stability of ${\rm AdS}_p \times {\rm S}^n \times {\rm S}^{q-n}$. The initial data constructed by De Wolfe et al \cite{Gary} has been carefully analyised and we have confirmed that...
Brane-World and Holography (2001)
Shiromizu, Tetsuya, Torii, Takashi, Ida, Daisuke
We consider the brane-world in the holographic point of view. Bearing the realistic models in mind, the bulk massless scalar field is introduced. First of all, we find the constraint on the coupling...
Charged Brane-World Black Holes (2001)
Chamblin,Andrew, Reall,Harvey S., Shinkai,Hisa-aki, Shiromizu,Tetsuya
We study charged brane-world black holes in the model of Randall and Sundrum in which our universe is viewed as a domain wall in asymptotically anti-de Sitter space. Such black holes can carry two...
Anti-de Sitter no-hair, AdS/CFT and the brane-world (2001)
Shiromizu, Tetsuya, Ida, Daisuke
We study the asymptotic behavior of the bulk spacetimes with the negative cosmological constant in the context of the brane-world scenario. We show that, in Euclidean bulk, or in Lorentzian static...
Charged Brane-World Black Holes (2001)
Chamblin, Andrew, Reall, Harvey S., Shinkai, Hisa-aki, Shiromizu, Tetsuya
We study charged brane-world black holes in the model of Randall and Sundrum in which our universe is viewed as a domain wall in asymptotically anti-de Sitter space. Such black holes can carry two...
Black holes in the brane world: Time symmetric initial data (2000)
Shiromizu,Tetsuya, Shibata,Masaru
We numerically construct time-symmetric initial data sets of a black hole in the Randall-Sundrum brane world model, assuming that the black hole is spherical on the brane. We find that the apparent...
Charged Brane-World Black Holes (2000)
Chamblin, Andrew, Reall, Harvey S., Shinkai, Hisa-aki, Shiromizu, Tetsuya
We study charged brane-world black holes in the model of Randall and Sundrum in which our universe is viewed as a domain wall in asymptotically anti-de Sitter space. Such black holes can carry two...
Black holes in the brane world:Time symmetric initial data (2000)
Shiromizu, Tetsuya, Shibata, Masaru
We numerically construct time-symmetric initial data sets of a black hole in the Randall-Sundrum brane world model, assuming that the black hole is spherical on the brane. We find that the apparent...
Fate of Kaluza-Klein Bubble (2000)
Shinkai, Hisa-aki, Shiromizu, Tetsuya
We numerically study classical time evolutions of Kaluza-Klein bubble space-time which has negative energy after a decay of vacuum. As the zero energy Witten's bubble space-time, where the bubble...
Black holes in the brane world: Time symmetric initial data (2000)
Shiromizu, Tetsuya, Shibata, Masaru
We numerically construct time-symmetric initial data sets of a black hole in the Randall-Sundrum brane world model, assuming that the black hole is spherical on the brane. We find that the apparent...
Global structure of exact cosmological solutions in the brane world (1999)
Mukohyama, Shinji, Shiromizu, Tetsuya, Maeda, Kei-ichi
We find the explicit coordinate transformation which links two exact cosmological solutions of the brane world which have been recently discovered. This means that both solutions are exactly the same...
Gravity, Stability and Energy Conservation on the Randall-Sundrum Brane-World (1999)
Sasaki, Misao, Shiromizu, Tetsuya, Maeda, Kei-ichi
We carefully investigate the gravitational perturbation of the Randall-Sundrum (RS) single brane-world solution [hep-th/9906064], based on a covariant curvature tensor formalism recently developed by...
A Probe Particle in Kerr-Newman-deSitter Cosmos (1999)
Shiromizu, Tetsuya, Gen, Uchida
We consider the force acting on a spinning charged test particle (probe particle) with the mass m and the charge q in slow rotating the Kerr-Newman-deSitter(KNdS) black hole with the mass M and the...
The Einstein Equations on the 3-Brane World (1999)
Shiromizu, Tetsuya, Maeda, Kei-ichi, Sasaki, Misao
We carefully investigate the gravitational equations of the brane world, in which all the matter forces except gravity are confined on the 3-brane in a 5-dimensional spacetime with $Z_2$ symmetry. We...
Cosmological Spinning Multi-`Black-Hole' Solution in String Theory (1999)
We give a cosmological spinning multi-`black-hole' solution in the Einstein-Maxwell-Dilaton-Axion theory with a positive cosmological constant. This solution is the cosmological dilatonic...
Stringy Probe Particle and Force Balance (1999)
We directly derive the classical equation of motion, which governs the centre of mass of a test string, from the string action. In a certain case, the equation is basically same as one derived by...
Dilatonic Probe, Force Balance and Gyromagnetic Ratio (1999)
Following the Papapetrou-Dixon-Wald procedure we derive the equation of motion for a dilatonic test body(probe) with the dilaton coupling $\alpha = {\sqrt {p/(2+p)}}$ in four dimension. Since the...
Shiromizu, Tetsuya, Gen, Uchida
We define space-times which are asymptotic to radiation dominant Friedman-Robertson-Walker space-times at timelike infinity and study the asymptotic structure. We discuss the local asymptotic...
Gravitational Mass in Asymptotically de Sitter Space-Times with Compactified Dimensions (1999)
We define gravitational mass in asymptotically de Sitter space-times with compactified dimension. It was shown that the mass can be negative for space-time with matter spreading beyond the...
Perturbation Analysis of Deformed Q-Balls and Primordial Magnetic Field (1998)
Shiromizu, Tetsuya, Uesugi, Tomoko, Aoki, Mayumi
We study the excited states of the Q-balls by performing stationary perturbation on the spherical Q-balls. We find the exact solution of the stationary perturbation of the global Q-ball with thin...
Shiromizu, Tetsuya, Nishi, Ryoichi
We take account of the lowest order back reaction on the fluid and modify the Kulsrud and Anderson equation $\partial_t{\cal E}_M= 2 \gamma {\cal E}_M$ obtained in the kinetic dynamo theory, where...
Inverse Cascade of Primordial Magnetic Field in MHD Turbulence (1998)
The feature of the spectrum of primordial magnetic field is studied by using renormalization group analysis in magnetohydrodynamics. Taking account of the renormalized resistivity at the fixed point,...
Asymptotic Schwarzschild Spacetimes (1998)
Gen, Uchida, Shiromizu, Tetsuya
It is shown that if an asymptotically flat spacetime is asymptotically stationary, in the sense that $\Lie_{\xi} g_{ab}$ vanishes at the rate $\sim t^{-3}$ for asymptotically timelike vector field...
Generation of Magnetic Field due to Excited Q-Balls (1998)
We investigate phase transitions due to excited Q-balls. As excited Q-balls have angular momentum, a magnetic field can be generated if one considers gauged Q-balls. Based on the course of the phase...
Timelike Infinity and Asymptotic Symmetry (1997)
Gen, Uchida, Shiromizu, Tetsuya
By extending Ashtekar and Romano's definition of spacelike infinity to the timelike direction, a new definition of asymptotic flatness at timelike infinity for an isolated system with a source is...
Freely falling 2-surfaces and the quasi-local energy (1997)
Ikumi, Keita, Shiromizu, Tetsuya
We derive an expression for effective gravitational mass for any closed spacelike 2-surface. This effective gravitational energy is defined directly through the geometrical quantity of the freely...
Shibata, Fumiaki, Morikawa, Masahiro, Shiromizu, Tetsuya, Yamaguchi, Masahide
Back reaction of the particle creation on the quantum tunneling process is analyzed in real time formalism. We use quantum potential method in which whole quantum dynamics is exactly projected to a...
Quantum Subcritical Bubbles (1996)
Uesugi, Tomoko, Morikawa, Masahiro, Shiromizu, Tetsuya
We quantize subcritical bubbles which are formed in the weakly first order phase transition. We find that the typical size of the thermal fluctuation reduces in the quantum-statistical physics. We...
Small Thermal Fluctuation on a Large Domain (1996)
Shiromizu, Tetsuya, Morikawa, Masahiro
Weak first-order phase transitions proceed with percolation of new phase. The kinematics of this process is clarified from the point of view of subcritical bubbles. We examine the effect of small...
Quantum Decoherence of Subcritical Bubble in Electroweak Phase Transition (1995)
In a weakly first order phase transition the typical scale of a subcritical bubble calculated in our previous papers turned out to be too small. At this scale quantum fluctuations may dominate and...
Dynamics of Subcritical Bubbles in First Order Phase Transition (1995)
Shiromizu, Tetsuya, Morikawa, Masahiro, Yokoyama, Jun'ichi
We derivate the Langevin and the Fokker-Planck equations for the radius of $O(3)$-symmetric subcritical bubbles as a phenomenological model to treat thermal fluctuation. The effect of thermal noise...
Volume Expansion Rate and The Age of The Universe (1995)
Nakamura, Takashi, Nakao, Ken-ichi, Chiba, Takeshi, Shiromizu, Tetsuya
Under four assumptions such that 1) Einstein's theory of gravity is correct, 2) existence of foliation by geodesic slicing, 3) the trace of the extrinsic curvature, $K$, is negative at the present...
Thermal fluctuations in electroweak phase transition (1995)
Shiromizu, Tetsuya, Morikawa, Masahiro, Yokoyama, Jun'ichi
We estimate the amplitude of thermal fluctuations by calculating the typical size of subcritical bubbles in cosmological electroweak phase transition and show that this thermal fluctuation effect...
A Cosmological Constant Limits the Size of Black Holes (1993)
Hayward, Sean A., Shiromizu, Tetsuya, Nakao, Ken-ichi
In a space-time with cosmological constant $\Lambda>0$ and matter satisfying the dominant energy condition, the area of a black or white hole cannot exceed $4\pi/\Lambda$. This applies to event...