Results for "Hiroyuki Nakano"

total 2032took 0.22s
Comparing an analytical spacetime metric for a merging binary to a fully non-linear numerical evolution using curvature scalarsFeb 08 2018We introduce a new geometrically invariant prescription for comparing two different spacetimes based on geodesic deviation. We use this method to compare a family of recently introduced analytical spacetime representing inspiraling black-hole binaries ... More
Soft Supersymmetry Breaking at Heavy Chiral ThresholdDec 28 2006We discuss the structure of threshold corrections to soft supersymmetry-breaking parameters at the mass threshold of heavy chiral superfields. Nontrivial dependence on soft parameters of heavy matter fields originates from the `physical' definition of ... More
A note on gravitational wave extraction from binary simulationsJan 13 2015Aug 20 2015In previous works, we developed a perturbative extrapolation formula to obtain gravitational waves at infinity from binary black hole simulations, based on the Regge-Wheeler-Zerilli formalism. In practice, this formula was basically derived in a background ... More
Gravitational reaction force on a particle in the Schwarzschild backgroundOct 10 2000Jan 17 2001We formulate a new method to calculate the gravitational reaction force on a particle of mass $\mu$ orbiting a massive black hole of mass $M$. In this formalism, the tail part of the retarded Green function, which is responsible for the reaction force, ... More
BEC-Polaron gas in a boson-fermion mixture : a many-body extension of Lee-Low-Pines theoryDec 15 2015May 18 2016We investigate the ground state properties of the gaseous mixture of a single species of bosons and fermions at zero temperature, where bosons are major in population over fermions, and form the Bose-Einstein condensate (BEC). The boson-boson and boson-fermion ... More
Second and higher-order quasi-normal modes in binary black hole mergersApr 26 2007Aug 03 2007Black hole (BH) oscillations known as quasi-normal modes (QNMs) are one of the most important gravitational wave (GW) sources. We propose that higher perturbative order of QNMs, generated by nonlinear gravitational interaction near the BHs, are detectable ... More
Gravitational waves from dark matter collapse in a starOct 04 2015Jan 14 2016We investigate the collapse of clusters of weakly interacting massive particles (WIMPs) in the core of a Sun-like star and the possible formation of mini-black holes and the emission of gravitational waves. When the number of WIMPs is small, thermal pressure ... More
Second Order Quasi-Normal Mode of the Schwarzschild Black HoleAug 03 2007We formulate and calculate the second order quasi-normal modes (QNMs) of a Schwarzschild black hole (BH). Gravitational wave (GW) from a distorted BH, so called ringdown, is well understood as QNMs in general relativity. Since QNMs from binary BH mergers ... More
How close can we approach the event horizon of the Kerr black hole from the detection of the gravitational quasinormal modes?Feb 07 2016Using the WKB method, we show that the peak location ($r_{\rm peak}$) of the potential, which determines the quasinormal mode frequency of the Kerr black hole, obeys an accurate empirical relation as a function of the specific angular momentum $a$ and ... More
On Detection of Black Hole Quasi-Normal Ringdowns: Detection Efficiency and Waveform Parameter Determination in Matched FilteringOct 08 2004Gravitational radiation from a slightly distorted black hole with ringdown waveform is well understood in general relativity. It provides a probe for direct observation of black holes and determination of their physical parameters, masses and angular ... More
Regular second order perturbations of binary black holes: The extreme mass ratio regimeApr 24 2008In order to derive the precise gravitational waveforms for extreme mass ratio inspirals (EMRI), we develop a formulation for the second order metric perturbations produced by a point particle moving in the Schwarzschild spacetime. The second order waveforms ... More
New method to integrate 2+1 wave equations with Dirac's delta functions as sourcesJan 17 2008Gravitational perturbations in a Kerr black hole background can not be decomposed into simple tensor harmonics in the time domain. Here, we make the mode decomposition only in the azimuthal direction and discuss the resulting (2+1)-dimensional Klein-Gordon ... More
Regular second order perturbations of extreme mass ratio black hole binariesJan 05 2007We report on the first results of self-consistent second order metric perturbations produced by a point particle moving in the Schwarzschild spacetime. The second order waveforms satisfy a wave equation with an effective source term build up from products ... More
A new method to integrate (2+1)-wave equations with Dirac's delta functions as sourcesFeb 28 2008Apr 21 2008Unlike in the Schwarzschild black hole background, gravitational perturbations in a Kerr black hole background can not be decomposed into simple tensor harmonics in the time domain. Here, we make mode decompositions only in the azimuthal direction. As ... More
Three-body equations of motion in successive post-Newtonian approximationsOct 29 2007There are periodic solutions to the equal-mass three-body (and N-body) problem in Newtonian gravity. The figure-eight solution is one of them. In this paper, we discuss its solution in the first and second post-Newtonian approximations to General Relativity. ... More
Gravitational Self-Force Correction to the Innermost Stable Circular Equatorial Orbit of a Kerr Black HoleApr 24 2014Oct 16 2014For a self-gravitating particle of mass \mu in orbit around a Kerr black hole of mass M >> \mu, we compute the O(\mu/M) shift in the frequency of the innermost stable circular equatorial orbit (ISCEO) due to the conservative piece of the gravitational ... More
Gauge Problem in the Gravitational Self-Force I. Harmonic Gauge Approach in the Schwarzschild BackgroundAug 21 2002The metric perturbation induced by a particle in the Schwarzschild background is usually calculated in the Regge-Wheeler (RW) gauge, whereas the gravitational self-force is known to be given by the tail part of the metric perturbation in the harmonic ... More
Accuracy of the Post-Newtonian Approximation for Extreme-Mass Ratio Inspirals from Black-hole Perturbation ApproachJan 10 2016May 25 2016We revisit the accuracy of the post-Newtonian (PN) approximation and its region of validity for quasi-circular orbits of a point particle in the Kerr spacetime, by using an analytically known highest post-Newtonian order gravitational energy flux and ... More
Gauge Problem in the Gravitational Self-Force II. First Post Newtonian Force under Regge-Wheeler GaugeAug 11 2003Oct 02 2003We discuss the gravitational self-force on a particle in a black hole space-time. For a point particle, the full (bare) self-force diverges. It is known that the metric perturbation induced by a particle can be divided into two parts, the direct part ... More
The detection of Quasinormal Mode of Pop III Binary Black Hole merger with final $M \sim 60M_\odot$ and $a/M \sim 0.7$ would confirm the strong gravity space-time around $\sim 2M$ which is only $\sim 1.17$ times the event horizon radiusJan 04 2016Jan 26 2016Recent population synthesis simulations of Pop III stars suggest that the event rate of coalescence of $\sim 30M_\odot$--$30M_\odot$ binary black holes can be high enough for the detection by the second generation gravitational wave detectors. The frequencies ... More
Possible confirmation of the existence of ergoregion by the Kerr quasinormal mode in gravitational waves from Pop III massive black hole binaryJan 26 2016Feb 01 2016The existence of the ergoregion of the Kerr space-time has not been confirmed observationally yet. We show that the confirmation would be possible by observing the quasinormal mode in gravitational waves. As an example, using the recent population synthesis ... More
Self-force Regularization in the Schwarzschild SpacetimeNov 30 2004We discuss the gravitational self-force on a particle in a black hole space-time. For a point particle, the full (bare) self-force diverges. The metric perturbation induced by a particle can be divided into two parts, the direct part (or the S part) and ... More
Spin flips in generic black hole binariesJun 15 2015Jan 18 2016We study the spin dynamics of individual black holes in a binary system. In particular we focus on the polar precession of spins and the possibility of a complete flip of spins with respect to the orbital plane. We perform a full numerical simulation ... More
Black Strings in Our WorldMar 14 2005The brane world scenario is a new approach to resolve the problem on how to compactify the higher dimensional spacetime to our 4-dimensional world. One of the remarkable features of this scenario is the higher dimensional effects in classical gravitational ... More
Self-Force on a Scalar Charge in Circular Orbit around a Schwarzschild Black HoleApr 04 2001Apr 12 2001In an accompanying paper, we have formulated two types of regulariz_ation methods to calculate the scalar self-force on a particle of charge $q$ moving around a black hole of mass $M$, one of which is called the ``power expansion regularization''. In ... More
Covariant Self-force Regularization of a Particle Orbiting a Schwarzschild Black Hole - Mode Decomposition Regularization -Nov 21 2001Covariant structure of the self-force of a particle in a general curved background has been made clear in the cases of scalar [Quinn], electromagnetic [DeWittBrehme], and gravitational charges [QuinnWald]. Namely, what we need is the part of the self-field ... More
BEC polaron in harmonic trap potential at weak coupling regime: Lee-Low-Pines type approachOct 03 2016We have calculated the zero-temperature binding energy of a single impurity atom immersed in a Bose-Einstein condensate of ultracold atoms that are trapped in an axially symmetric harmonic potential, where the impurity interacts with bosonic atoms in ... More
The possible existence of Pop III NS-BH binary and its detectabilityOct 02 2016In the population synthesis simulations of Pop III stars, many BH (Black Hole)-BH binaries with merger time less than the age of the Universe $(\tau_{\rm H})$ are formed, while NS (Neutron Star)-BH binaries are not. The reason is that Pop III stars have ... More
The detection of quasinormal mode with $a/M \sim 0.95$ would prove a sphere $99\%$ soaking in the ergoregion of the Kerr space-timeFeb 09 2016Recent numerical relativity simulations of mergers of binary black holes suggest that the maximum final value of $a/M$ is $\sim 0.95$ for the coalescence of two equal mass black holes with aligned spins of the same magnitude $a/M=0.994$ which is close ... More
Bose-Einstein condensation and density collapse in a weakly coupled boson-fermion mixtureDec 15 2014We investigate the mechanical instability toward density collapse and the transition temperature of Bose-Einstein condensation in the weakly coupled boson-fermion many-body mixture of single-component boson and fermion gases, in the case of the repulsive ... More
Gravitational wave quasinormal mode from Population III massive black hole binaries in various models of population synthesisJun 01 2016Focusing on the remnant black holes after merging binary black holes, we show that ringdown gravitational waves of Population III binary black holes mergers can be detected with the rate of $5.9-500~{\rm events~yr^{-1}}~({\rm SFR_p}/ (10^{-2.5}~M_\odot~{\rm ... More
Possible golden events for ringdown gravitational wavesJun 01 2015Sep 03 2015There is a forbidden region in the parameter space of quasinormal modes of black holes in general relativity. Using both inspiral and ringdown phases of gravitational waves from binary black holes, we propose two methods to test general relativity. We ... More
Shattering by turbulence as a production source of very small grainsJun 11 2010The origin of grain size distribution in the interstellar medium is one of the most fundamental problems in the interstellar physics. In the Milky Way, smaller grains are more abundant in number, but their origins are not necessarily specified and quantified. ... More
Higgs Inflation and Scalar Dark Matter with Right-handed NeutrinosApr 27 2015We investigate the possibility of Higgs inflation with an extended standard model by right-handed neutrinos and scalar dark matter. We find that the masses of the dark matter and one of the right-handed neutrinos should stand around TeV and $10^{-14}$ ... More
A central extension of U_q sl(2,2)^{(1)} and R-matrices with a new parameterApr 25 2003Jun 30 2003In this paper, using a quantum superalgebra associated with the universal central extension of sl(2,2)^{(1)}, we introduce new R-matrices having an extra parameter x. As x\to 0, they become those associated with the symmetric and anti-symmetric tensor ... More
Field-free, spin-current control of magnetization in non-collinear chiral antiferromagnetsOct 24 2016Non-collinear chiral antiferromagnets like Mn3Sn and Mn3Ge are known to show gigantic anomalous Hall response depending on the orientation of their inverse chiral magnetic order of Mn atoms in Kagome layers. Here we study the stability of such magnetic ... More
How far can Tarzan jump?Aug 21 2012The tree-based rope swing is a popular recreation facility, often installed in outdoor areas, giving pleasure to thrill-seekers. In the setting, one drops down from a high platform, hanging from a rope, then swings at a great speed like "Tarzan", and ... More
Sequestering in models of F-term upliftingSep 05 2008We discuss the nature of sequestering supersymmetry breaking sectors in a certain class of moduli stabilization in supergravity/string models, where a negative vacuum energy of the nonperturbative moduli potential is canceled by dynamically generated ... More
Dynamical symmetry breaking on a brane with bulk gauge theoryDec 20 2003Aug 03 2004We analyze a structure of dynamical chiral symmetry breaking in orbifold gauge theories with matter fields (fermions) on the fixed point. We find that the boundary chiral phase structure of QED and QCD on the orbifold is quite nontrivial depending on ... More
A Method For Determining Two-Dimensional Orbits In Galactic DisksAug 16 2004Jan 04 2005We propose a method for determining the two-dimensional orbits of interstellar matter (ISM) in galactic disks using observed line-of-sight velocity fields. Although four components, consisting of two of position and two of velocity, are necessary to determine ... More
Localizations in coupled electronic chainsOct 06 1998We studied effects of random potentials and roles of electron-electron interactions in the gapless phase of coupled Hubbard chains, using a renormalization group technique. For non-interacting electrons, we obtained the localization length proportional ... More
Persistent current of two-chain Hubbard model with impuritiesApr 24 1998The interplay between impurities and interactions is studied in the gapless phase of two-chain Hubbard model in order to see how the screening of impurity potentials due to repulsive interactions in single-chain model will be changed by increasing the ... More
Electric-Magnetic Duality in IIB Matrix Model with D-braneAug 02 2000We consider electric-magnetic duality(S-duality) in IIB matrix model with a D3-brane background. We propose the duality transformation by considering that of noncommutative Yang-Mills theory(NCYM) in four dimension. NCYM derived from the matrix model ... More
Maxwell Theory from Matrix ModelOct 31 2000Nov 01 2000We present a scenario for deriving Maxwell theory from IIB matrix model. Four dimensional spacetime and theories on it relate different dimensional ones by applying appropriate limits of the backgrounds of matrix model. It is understood by looking at ... More
Tambarization of a Mackey functor and its application to the Witt-Burnside constructionOct 05 2010For an arbitrary group $G$, a (semi-)Mackey functor is a pair of covariant and contravariant functors from the category of $G$-sets, and is regarded as a $G$-bivariant analog of a commutative (semi-)group. In this view, a $G$-bivariant analog of a (semi-)ring ... More
Excitation spectrum of d-wave Fermi surface deformationAug 21 2004Several instabilities competing with the d-wave singlet pairing were proposed for high-Tc cuprates. One of them is the d-wave Fermi surface deformation (dFSD), which is generated by forward scattering. In this paper, correlation functions of the dFSD ... More
Electronic nematic phase transition in the presence of anisotropyJan 19 2014Sep 29 2014We study the phase diagram of electronic nematic instability in the presence of xy anisotropy. While a second order transition cannot occur in this case, mean-field theory predicts that a first order transition occurs near van Hove filling and its phase ... More
Self-masking of spontaneous symmetry breaking in layer materialsJun 13 2008Apr 20 2009We study d-wave Fermi surface deformations (dFSD), the so-called Pomeranchuk instability, on bilayer and infinite-layer square lattices. Since the order parameter of the dFSD has Ising symmetry, there are two stacking patterns along the c axis: (+,+) ... More
Effect of magnetic field on spontaneous Fermi surface symmetry breakingMay 29 2007We study magnetic field effects on spontaneous Fermi surface symmetry breaking with d-wave symmetry, the so-called d-wave "Pomeranchuk instability''. We use a mean-field model of electrons with a pure forward scattering interaction on a square lattice. ... More
Well-posedness and scattering for nonlinear Schrödinger equations with a derivative nonlinearity at the scaling critical regularityNov 13 2013In the present paper, we consider the Cauchy problem of nonlinear Schr\"odinger equations with a derivative nonlinearity which depends only on $\bar{u}$. The well-posedness of the equation at the scaling subcritical regularity was proved by A. Gr\"unrock ... More
On symmetry groups of oriented matroidsJan 28 2013Jun 11 2015Symmetries of geometric structures such as hyperplane arrangements, point configurations and polytopes have been studied extensively for a long time. However, symmetries of oriented matroids, a common combinatorial abstraction of them, are not understood ... More
Counting functions for branched covers of elliptic curves and quasi-modular formsSep 19 1999We prove that each counting function of the m-simple branched covers with a fixed genus of an elliptic curve is expressed as a polynomial of the Eisenstein series E_2, E_4 and E_6 . The special case m=2 is considered by Dijkgraaf.
Resolutions of DG-modules and their applications to commutative DG-algebrasFeb 06 2018A DG-version of projective resolution and injective resolution of DG-modules over DG-algebra are already known. In the first half of this paper, we introduce another DG-version for DG-modules over a connective DG-algebra and show that they behave nicely ... More
Dust growth in the interstellar medium: How do accretion and coagulation interplay?Feb 07 2012Dust grains grow in interstellar clouds by accretion and coagulation. In this paper, we focus on these two grain growth processes and numerically investigate how they interplay to increase the grain radii. We show that accretion efficiently depletes grains ... More
Buckling of Carbon Nanotubes: A State of the Art ReviewDec 20 2011The nonlinear mechanical response of carbon nanotubes, referred to as their "buckling" behavior, is a major topic in the nanotube research community. Buckling means a deformation process in which a large strain beyond a threshold causes an abrupt change ... More
Spontaneous and dynamical symmetry breaking in higher-dimensional space-time with boundary termsJul 01 2003In this thesis we study physics beyond the standard model focusing on the quantum field theory in higher-dimensional space-time with some boundary terms. The boundary term causes nontrivial consequences about the vacuum structure of the higher-dimensional ... More
A finite number of defining relations and a UCE theorem of the elliptic Lie algebras and superalgebras with rank $\geq 2$Aug 26 2004In this paper, we give a finite number of defining relations satisfied by a finite number of generators for the elliptic Lie algebras and superalgebras ${\frak g}_R$ with rank $\geq 2$. Here the $R$'s denote the reduced and non-reduced elliptic root systems ... More
Hadron Correlations and Fluctuations in 40, 80, and 158 AGeV/c Pb-Au CollisionsMay 16 2003Measurements of HBT correlations and event-by-event fluctuations of mean pT and the net charge in Pb-Au collisions at 40, 80, and 158 AGeV/c are presented. From comparisons of HBT radii measured from AGS to RHIC energies, a universal mean free path of ... More
A generalization of The Dress construction for a Tambara functor, and polynomial Tambara functorsDec 09 2010May 24 2011For a finite group $G$, (semi-)Mackey functors and (semi-)Tambara functors are regarded as $G$-bivariant analogs of (semi-)groups and (semi-)rings respectively. In fact if $G$ is trivial, they agree with the ordinary (semi-)groups and (semi-)rings, and ... More
4 D Quantum N-Dilaton Gravity and One-Loop Divergence of Effective Action on Constant DilatonMay 04 1996We consider 4D quantum gravity with N-dilatons with the most general couplings. Especially, on constant dilaton and arbitrary metric background, we show the structure of the divergent terms. We show the constraint between the couplings necessary to cancel ... More
A Dai-Yuan-type Riemannian conjugate gradient method with the weak Wolfe conditionsMay 17 2014Jun 17 2016This article describes a new Riemannian conjugate gradient method and presents a global convergence analysis. The existing Fletcher-Reeves-type Riemannian conjugate gradient method is guaranteed to be globally convergent if it is implemented with the ... More
Derived bi-duality via homotopy limitOct 20 2012We show that a derived bi-duality dg-module is quasi-isomorphic to the homotopy limit of a certain tautological functor. This is a simple observation, which seems to be true in wider context. From the view point of derived Gabriel topology, this is a ... More
Comparison of Post-Newtonian and Numerical Evolutions of Black-Hole BinariesJan 24 2009In this paper, we compare the waveforms from the post-Newtonian (PN) approach with the numerical simulations of generic black-hole binaries which have mass ratio $q\sim0.8$, arbitrarily oriented spins with magnitudes $S_1/m_1^2\sim0.6$ and $S_2/m_2^2\sim0.4$, ... More
Intermediate-mass-ratio black hole binaries: intertwining numerical and perturbative techniquesAug 25 2010Dec 02 2010We describe in detail full numerical and perturbative techniques to compute the gravitational radiation from intermediate-mass-ratio black-hole-binary inspirals and mergers. We perform a series of full numerical simulations of nonspinning black holes ... More
Stationary Rotating Strings as Relativistic Particle MechanicsMar 28 2008Jun 23 2008Stationary rotating strings can be viewed as geodesic motions in appropriate metrics on a two-dimensional space. We obtain all solutions describing stationary rotating strings in flat spacetime as an application. These rotating strings have infinite length ... More
An Improved Search Method for Gravitational Ringing of Black HolesMar 16 2004A black hole has characteristic quasi-normal modes that will be excited when it is formed or when the geometry is perturbed. The state of a black hole when the quasi-normal modes are excited is called the gravitational ringing, and detections of it will ... More
Adiabatic radiation reaction to the orbits in Kerr SpacetimeJun 17 2005Geodesic motion of a point particle in Kerr geometry has three constants of motion, energy $E$, azimuthal angular momentum $L$, and Carter constant $Q$. Under the adiabatic approximation, radiation reaction effect is characterized by the time evolution ... More
Level statistics for one-dimensional Schrödinger operators and Gaussian beta ensembleDec 25 2013We study the level statistics for two classes of 1-dimensional random Schr\"odinger operators : (1) for operators whose coupling constants decay as the system size becomes large, and (2) for operators with critically decaying random potential. As a byproduct ... More
Spin of the ground state and the flux phase problem on the ringFeb 17 2004Apr 02 2004As a continuation of our previous work, we derive the optimal flux phase which minimizes the ground state energy in the one-dimensional many particle systems, when the number of particles is odd in the absence of on-site interaction and external potential. ... More
Light-quark baryon spectroscopy within ANL-Osaka dynamical coupled-channels approachFeb 08 2016Recent results on the study of light-quark baryons with the ANL-Osaka dynamical coupled-channels (DCC) approach are presented, which contain the N* and Delta* spectroscopy via the analysis of pi N and gamma N reactions and the Lambda* and Sigma* spectroscopy ... More
A criterion of graded coherentness of tensor algebras and its application to higher dimensional Auslander-Reiten theoryOct 19 2012Even if a ring A is coherent, the polynomial ring A[X] in one variable could fail to be coherent. In this note we show that A[X] is graded coherent with the standard grading deg X=1. More generally, we give a criterion of graded coherentness of the tensor ... More
Off-shell dimensional reduction of 5D orbifold supergravityOct 15 2007We present a systematic way for deriving a four-dimensional (4D) effective action of the five-dimensional (5D) orbifold supergravity respecting the N=1 {\it off-shell} structure. As an illustrating example, we derive a 4D effective theory of the 5D gauged ... More
Gauged $U(1)_R$ supergravity on orbifoldOct 11 2005We discuss a gauged $U(1)_R$ supergravity on five-dimensional orbifold ($S^1/Z_2$) in which a $Z_2$-even U(1) gauge field takes part in the $U(1)_R$ gauging, and show the structure of Fayet-Iliopoulos (FI) terms allowed in such model. Some physical consequences ... More
Fayet-Iliopoulos terms in five-dimensional orbifold supergravitySep 14 2004Oct 11 2005We derive an off-shell formulation for the boundary Fayet-Iliopoulos (FI) terms in locally supersymmetric U(1) gauge theory on 5D $S^1/Z_2$ orbifold. Some physical consequences of such FI terms, e.g., the supersymmetry breaking and the generation of 5D ... More
A simultaneous generalization of mutation and recollement on a triangulated categoryDec 07 2015In this article, we introduce the notion of {\it concentric twin cotorsion pair} on a triangulated category. This notion contains the notions of $t$-structure, cluster tilting subcategory, co-$t$-structure and functorally finite rigid subcategory as examples. ... More
Partial Tambara structure on the Burnside biset functor, induced from a derivator-like system of adjoint tripletsFeb 17 2015Dec 07 2015In the previous article 'A Mackey-functor theoretic interpretation of biset functors', we have constructed the 2-category $\mathbb{S}$ of finite sets with variable finite group actions, in which bicoproducts and bipullbacks exist. As shown in it, biset ... More
Equivalence of hearts of twin cotorsion pairs on triangulated categoriesJul 26 2014Dec 07 2015In this article, we investigate the condition for the hearts of twin cotorsion pairs to be equivalent, compatibly with the associated functors. This is related to the vanishing of components of pairs through the associated functors.
Cohomology theory in 2-categoriesNov 17 2008Recently, symmetric categorical groups are used for the study of the Brauer groups of symmetric monoidal categories. As a part of these efforts, some algebraic structures of the 2-category of symmetric categorical groups $\mathrm{SCG}$ are being investigated. ... More
Error Bounds for Augmented Truncations of Discrete-Time Block-Monotone Markov Chains under Geometric Drift ConditionsMay 16 2014Jul 17 2014This paper studies the augmented truncation of discrete-time block-monotone Markov chains under geometric drift conditions. We first present a bound for the total variation distance between the stationary distributions of an original Markov chain and ... More
A sufficient condition for the subexponential asymptotics of GI/G/1-type Markov chains with queueing applicationsOct 17 2013Jun 27 2014The main contribution of this paper is to present a new sufficient condition for the subexponential asymptotics of the stationary distribution of a GI/GI/1-type Markov chain without jumps from level "infinity" to level zero. For simplicity, we call such ... More
Remnant Masses, Spins and Recoils from the Merger of Generic Black-Hole BinariesApr 22 2009Apr 20 2010We obtain empirical formulae for the final remnant black hole mass, spin, and recoil velocity from merging black-hole binaries with arbitrary mass ratios and spins. Our formulae are based on the mass ratio and spin dependence of the post-Newtonian expressions ... More
Perturbations of Spacetime around a Stationary Rotating Cosmic StringNov 18 2008Feb 25 2009We consider the metric perturbations around a stationary rotating Nambu-Goto string in Minkowski spacetime. By solving the linearized Einstein equations, we study the effects of azimuthal frame-dragging around the rotation axis and linear frame-dragging ... More
Quasinormal Ringing for Acoustic Black Holes at Low TemperatureNov 09 2004May 13 2005We investigate a condensed matter ``black hole'' analogue, taking the Gross-Pitaevskii (GP) equation as a starting point. The linearized GP equation corresponds to a wave equation on a black hole background, giving quasinormal modes under some appropriate ... More
On the defining relations of the affine Lie superalgebras and their quantized universal enveloping superalgebrasMar 15 1996In this paper, we give defining relations of the affine Lie superalgebras an and defining relations of a super-version of the Drinfeld[D]-Jimbo[J] affine quantized universal enveloping algebras. As a result, we can exactly define the affine quantized ... More
Stable rank for inclusions of C*-algebrasAug 30 2007When a unital \ca $A$ has topological stable rank one (write $\tsr(A) = 1$), we know that $\tsr(pAp) \leq 1$ for a non-zero projection $p \in A$. When, however, $\tsr(A) \geq 2$, it is generally faluse. We prove that if a unital C*-algebra $A$ has a simple ... More
Properties of free-free, dust, and CO emissions in the starbursts of blue compact dwarf galaxiesDec 16 2012The central star-forming regions in three blue compact dwarf galaxies (He 2-10, NGC 5253, and II Zw 40) were observed in the 340 GHz (880 micron) band at 5 arcsec resolution with the Submillimetre Array (SMA). Continuum emission associated with the central ... More
A special value of the spectral zeta function of the non-commutative harmonic osciallatorsJul 06 2005The non-commutative harmonic oscillator is a $2\times2$-system of harmonic oscillators with a non-trivial correlation. We write down explicitly the special value at $s=2$ of the spectral zeta function of the non-commutative harmonic oscillator in terms ... More
Biset functors as module Mackey functors, and its relation to derivatorsJan 22 2016In this article, we will show that the category of biset functors can be regarded as a reflective monoidal subcategory of the category of Mackey functors on the 2-category of finite groupoids. This reflective subcategory is equivalent to the category ... More
Several adjoint constructions for biset functors via Mackey-functorial interpretationJun 13 2014We consider analogs of Jacobson's $F$-Burnside construction and Boltje's $(-)_+$-construction for biset functors, using Mackey-functor theoretic interpretation of biset functors.
Low Energy Investigations at Kamioka ObservatoryJan 30 2013At Kamioka Observatory many activities for low energy rare event search are ongoing. Super-Kamiokande(SK), the largest water Cherenkov neutrino detector, currently continues data taking as the fourth phase of the experiment (SK-IV). In SK-IV, we have ... More
Comparison of the definitions of Abelian 2-categoriesApr 01 2009Apr 03 2009In the efforts to define a 2-categorical analog of an abelian category, two (or three) notions of "abelian 2-categories" are defined. One is the relatively exact 2-category, and the other(s) is the (2-)abelian Gpd-category. We compare these notions. Since ... More
Magnetic excitations in La-based cuprate superconductors: slave-boson mean-field analysis of the two-dimensional t-J modelOct 22 2006Motivated by recent inelastic neutron scattering experiments up to a high-energy region for La-based cuprates, we compute (q,omega) maps of the imaginary part of the dynamical magnetic susceptibility chi(q,omega) in the slave-boson mean-field approximation ... More
The limit formula for the normalized fundamental matrix of the northwest-corner truncation of Markov chains: Matrix-infinite-product form solutions of block-Hessenberg Markov chainsMar 25 2016Jun 30 2016This paper considers the normalized fundamental matrix for the northwest-corner (NW-corner) truncation of ergodic continuous-time Markov chains, technically, of their infinitesimal generators. We first present a limit formula for the normalized fundamental ... More
Error bounds for augmented truncations of discrete-time block-monotone Markov chains under subgeometric drift conditionsJun 05 2015Nov 22 2016This paper studies the last-column-block-augmented northwest-corner truncation (LC-block-augmented truncation, for short) of discrete-time block-monotone Markov chains under subgeometric drift conditions. The main result of this paper is to present an ... More
Subexponential tail equivalence of the queue length distributions of BMAP/GI/1 queues with and without retrialsOct 17 2013Jul 06 2014The main contribution of this paper is to prove the subexponential tail equivalence of the stationary queue length distributions in the BMAP/GI/1 queues with and without retrials. We first present a stochastic-decomposition-like result of the stationary ... More
Fluctuation of density of states for 1d Schrödinger operatorsMay 19 2016We consider the 1d Schr\"odinger operator with random decaying potential and compute the 2nd term asymptotics of the density of states, which shows substantial differences between the cases $\alpha > \frac 12$, $\alpha < \frac 12$ and $\alpha = \frac ... More
Perturbative effects of spinning black holes with applications to recoil velocitiesNov 11 2010Recently, we proposed an enhancement of the Regge-Wheeler-Zerilli formalism for first-order perturbations about a Schwarzschild background that includes first-order corrections due to the background black-hole spin. Using this formalism, we investigate ... More
Asymptotically Matched Spacetime Metric for Non-Precessing, Spinning Black Hole BinariesAug 31 2012We construct a closed-form, fully analytical 4-metric that approximately represents the spacetime evolution of non-precessing, spinning black hole binaries from infinite separations up to a few orbits prior to merger. We employ the technique of asymptotic ... More
Intermediate-mass-ratio black hole binaries II: Modeling Trajectories and Gravitational WaveformsAug 22 2011We revisit the scenario of small-mass-ratio (q) black-hole binaries; performing new, more accurate, simulations of mass ratios 10:1 and 100:1 for initially nonspinning black holes. We propose fitting functions for the trajectories of the two black holes ... More
Calculating the gravitational self force in Schwarzschild spacetimeNov 01 2001Feb 14 2002We present a practical method for calculating the local gravitational self-force (often called ``radiation-reaction force'') for a pointlike particle orbiting a Schwarzschild black hole. This is an implementation of the method of {\it mode-sum regularization}, ... More