Results for "Hikaru Kawai"

total 878took 0.13s
A Background Independent Formulation of Noncritical String TheoryMar 22 1995Using the string field theory recently proposed by the authors and collaborators, we give a background independent formulation of rational noncritical string theories with $c\leq 1$. With a little modification of the string field Hamiltonians previously ... More
Quantum $R^2$ Gravity in Two DimensionsMar 02 1993Two-dimensional quantum gravity with an $R^2$ term is investigated in the continuum framework. It is shown that the partition function for small area $A$ is highly suppressed by an exponential factor $exp \{ -2\pi (1-h)^2/(m^2A) \}$, where $1/m^2$ is ... More
OPE between the energy-momentum tensor and the Wilson loop in N=4 Super-Yang-Mills theoryJun 07 2001Jul 10 2001We analyze the operator product expansion T_{\mu \nu}(z) W[C] in N=4 4-dimensional Super-Yang-Mills (SYM) theory with U(N) gauge group, and clarify that the closed Wilson loop does not possess an anomalous dimension and that only the shape of the loop ... More
Solving the Naturalness Problem by Baby Universes in the Lorentzian MultiverseOct 11 2011Jan 24 2012We propose a solution of the naturalness problem in the context of the multiverse wavefunction without the anthropic argument. If we include microscopic wormhole configurations in the path integral, the wave function becomes a superposition of universes ... More
AdS/CFT Correspondence as a Consequence of Scale InvarianceJun 08 2007Jun 21 2007We study an anisotropic scale transformation in the worldsheet description of D3-branes in Type IIB theory, and show that the transformation is really a symmetry in a region near D3-branes. AdS/CFT correspondence follows from this symmetry. We will explicitly ... More
Interior of Black Holes and Information RecoverySep 28 2015Jan 28 2016We analyze time evolution of a spherically symmetric collapsing matter from a point of view that black holes evaporate by nature. We first consider a spherical thin shell that falls in the metric of an evaporating Schwarzschild black hole of which the ... More
String Field Theory of Noncritical StringsJul 07 1993We construct the Hamiltonian operator of the string field theory for $c=0$ string theory. It describes how strings evolve in the coordinate frame, which is defined by using the geodesic distance on the worldsheet. The Hamiltonian consists of three-string ... More
Axial U(1) current in Grabowska and Kaplan's formulationMay 03 2017May 24 2017Recently, Grabowska and Kaplan suggested a non-perturbative formulation of a chiral gauge theory, which consists of the conventional domain-wall fermion and a gauge field that evolves by the gradient flow from one domain wall to the other. In this paper, ... More
Perturbative Vacua from IIB Matrix ModelAug 13 2007Nov 26 2007It has not been clarified whether a matrix model can describe various vacua of string theory. In this paper, we show that the IIB matrix model includes type IIA string theory. In the naive large N limit of the IIB matrix model, configurations consisting ... More
Weak scale from Planck scale -- Mass Scale Generation in Classically Conformal Two Scalar System --May 14 2019Jun 04 2019In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself can not explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for ... More
Matrix model with manifest general coordinate invarianceApr 09 2002May 22 2002We present a formulation of a matrix model which manifestly possesses the general coordinate invariance when we identify the large $N$ matrices with differential operators. In order to build a matrix model which has the local Lorentz invariance, we investigate ... More
Weak scale from Planck scale -- Mass Scale Generation in Classically Conformal Two Scalar System --May 14 2019May 15 2019In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself can not explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for ... More
Weak scale from Planck scale -- Mass Scale Generation in Classically Conformal Two Scalar System --May 14 2019May 20 2019In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself can not explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for ... More
A Model of Black Hole Evaporation and 4D Weyl AnomalyJan 12 2017Jan 24 2017We analyze time evolution of a spherically-symmetric collapsing matter from a point of view that black holes evaporate by nature. We consider conformal matters and solve the semi-classical Einstein equation $G_{\mu\nu}=8\pi G \langle T_{\mu\nu} \rangle$ ... More
Asymptotically Vanishing Cosmological Constant in the MultiverseApr 10 2011Apr 21 2011We study the problem of the cosmological constant in the context of the multiverse in Lorentzian spacetime, and show that the cosmological constant will vanish in the future. This sort of argument was started from Coleman in 1989, and he argued that the ... More
Gravitational string-membrane hedgehog and internal structure of black holesSep 21 2010Apr 23 2011We investigate charged Nambu-Goto strings/membrane systems in the Einstein-Maxwell theory in 3+1 dimensions. We first construct a charged string hedgehog solution that has a single horizon and conical singularity. Then we examine a charged membrane system, ... More
Soliton Solutions in Noncritical String Field Theory?Jun 20 1996We look for soliton solutions in $c=0$ noncritical string field theory constructed by the authors and collaborators. It is shown that the string field action itself is very complicated in our formalism but it satisfies a very simple equation. We derive ... More
Strings as Flux Tube and Deconfinement on Branes in Gauge TheoriesJun 13 2001Nov 17 2001We propose gauge theories in which the unstable branes and the fundamental string are realized as classical solutions. While the former are represented by domain wall like configurations of a scalar field coupled to the gauge field, the latter is by a ... More
Universality of soft theorem from locality of soft vertex operatorsMay 28 2018Sep 24 2018We show the universal soft behavior of massless particles at the tree level by considering the operator product expansion of the soft vertex operator with the hard vertex operators. We find that after eliminating total derivative terms the world-sheet ... More
Phenomenological Description of the Interior of the Schwarzschild Black HoleSep 19 2014Mar 26 2015We discuss a sufficiently large 4-dimensional Schwarzschild black hole which is in equilibrium with a heat bath. In other words, we consider a black hole which has grown up from a small one in the heat bath adiabatically. We express the metric of the ... More
Weak scale from Planck scale -- Mass Scale Generation in Classically Conformal Two Scalar System --May 14 2019In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself can not explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for ... More
Bi-local Fields in Noncommutative Field TheoryJan 07 2000We propose a bi-local representation in noncommutative field theory. It provides a simple description for high momentum degrees of freedom. It also shows that the low momentum modes can be well approximated by ordinary local fields. Long range interactions ... More
Ultraviolet Stable Fixed Point and Scaling Relations in 2+$ε$ Dimensional Quantum GravityMar 23 1993Apr 02 1993We formulate a renormalizable quantum gravity in $2+\epsilon$ dimensions by generalizing the nonlinear sigma model approach to string theory. We find that the theory possesses the ultraviolet stable fixed point if the central charge of the matter sector ... More
Saddle point inflation in string-inspired theoryJul 11 2015Aug 05 2015The observed value of the Higgs mass indicates the possibility that there is no supersymmetry below the Planck scale and that the Higgs can play the role of the inflaton. We examine the general structure of the saddle point inflation in string-inspired ... More
Natural solution to the naturalness problem -- Universe does fine-tuningSep 20 2015We propose a new mechanism to solve the fine-tuning problem. We start from a multi-local action $ S=\sum_{i}c_{i}S_{i}+\sum_{i,j}c_{i,j}S_{i}S_{j}+\sum_{i,j,k}c_{i,j,k}S_{i}S_{j}S_{k}+\cdots$, where $S_{i}$'s are ordinary local actions. Then, the partition ... More
Weak Scale From the Maximum Entropy PrincipleSep 23 2014Mar 28 2015The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although ... More
Describing Curved Spaces by MatricesAug 27 2005May 09 2006It is shown that a covariant derivative on any d-dimensional manifold M can be mapped to a set of d operators acting on the space of functions on the principal Spin(d)-bundle over M. In other words, any d-dimensional manifold can be described in terms ... More
A novel regularization of chiral gauge theoryJun 01 2018We propose a novel gauge-invariant regularization for the perturbative chiral gauge theory.Our method consists of the two ingredients: use of the domain-wall fermion to describe a chiral fermion with Pauli-Villars regulators and application of the di- ... More
Factorization of the Effective Action in the IIB Matrix ModelMay 07 2012We study the low-energy effective action of the IIB matrix model in the derivative interpretation, where the diffeomorphism invariance is manifest and arbitrary manifolds are described by matrices. We show that it is expressed as a sum of terms, each ... More
Supersymmetric large-N reduced model with multiple matterDec 02 2003Feb 23 2004We showed in hep-th/0303210 that the Dijkgraaf-Vafa theory can be regarded as large-N reduction in the case of $\mathcal{N}=1$ supersymmetric U(N) gauge theories, with single adjoint matter. We generalize this to gauge theories with gauge groups being ... More
Dijkgraaf-Vafa theory as large-N reductionMar 24 2003May 29 2003We construct a large-N twisted reduced model of the four-dimensional super Yang-Mills theory coupled to one adjoint matter. We first consider a non-commutative version of the four-dimensional superspace, and then give the mapping rule between matrices ... More
Minimal Higgs inflationAug 30 2013Dec 14 2013We consider a possibility that the Higgs field in the Standard Model (SM) serves as an inflaton when its value is around the Planck scale. We assume that the SM is valid up to an ultraviolet cutoff scale \Lambda, which is slightly below the Planck scale, ... More
Spacetime Structure of the Black Hole EvaporationMar 26 2012Feb 19 2013We study a self-consistent solution of the semi-classical Einstein equation including the back reaction from the Hawking radiation. Our geometry is constructed by connecting flat space and the outgoing Vaidya metric at the locus of the shock wave. In ... More
Scaling Exponents in Quantum Gravity near Two DimensionsJun 22 1992Jun 25 1992We formulate quantum gravity in $2+\epsilon$ dimensions in such a way that the conformal mode is explicitly separated. The dynamics of the conformal mode is understood in terms of the oversubtraction due to the one loop counter term. The renormalization ... More
Large N reduction on coset spacesFeb 11 2010Apr 27 2010As an extension of our previous work concerning the large N reduction on group manifolds, we study the large N reduction on coset spaces. We show that large N field theories on coset spaces are described by certain corresponding matrix models. We also ... More
Eternal Higgs inflation and cosmological constant problemJan 19 2015Jul 21 2015We investigate the Higgs potential beyond the Planck scale in the superstring theory, under the assumption that the supersymmetry is broken at the string scale. We identify the Higgs field as a massless state of the string, which is indicated by the fact ... More
Bare Higgs mass at Planck scaleOct 09 2012Jan 19 2015We compute one- and two-loop quadratic divergent contributions to the bare Higgs mass in terms of the bare couplings in the Standard Model. We approximate the bare couplings, defined at the ultraviolet cutoff scale, by the MS-bar ones at the same scale, ... More
A Self-consistent Model of the Black Hole EvaporationFeb 19 2013We construct a self-consistent model which describes a black hole from formation to evaporation including the back reaction from the Hawking radiation. In the case where a null shell collapses, at the beginning the evaporation occurs, but it stops eventually, ... More
A note on graviton exchange in emergent gravity scenarioOct 31 2016Feb 28 2017It is well-known that there exists a close relation between a large $N$ matrix model and noncommutative (NC) field theory: The latter can be naturally obtained from the former by expanding it around a specific background. Because the matrix model can ... More
A note on graviton exchange in emergent gravity scenarioOct 31 2016It is well-known that there exists a close relation between a large $N$ matrix model and noncommutative (NC) field theory: The latter can be naturally obtained from the former by expanding it around a specific background. Because the matrix model can ... More
Predictions on mass of Higgs portal scalar dark matter from Higgs inflation and flat potentialApr 24 2014Jan 25 2015We consider the Higgs portal $Z_2$ scalar model as the minimal extension of the Standard Model (SM) to incorporate the dark matter. We find that the dark matter mass is bounded to be lighter than 1000\,GeV within the framework that we have proposed earlier, ... More
Bare Higgs mass and potential at ultraviolet cutoffMay 30 2013We first review the current status of the top mass determination paying attention to the difference between the MS-bar and pole masses. Then we present our recent result on the bare Higgs mass at a very high ultraviolet cutoff scale.
Universality of Nonperturbative Effect in Type 0 String TheoryDec 01 2004We derive the nonperturbative effect in type 0B string theory, which is defined by taking the double scaling limit of a one-matrix model with a two-cut eigenvalue distribution. However, the string equation thus derived cannot determine the nonperturbative ... More
Evidence of the Big FixMay 06 2014Sep 09 2014We give an evidence of the Big Fix. The theory of wormholes and multiverse suggests that the parameters of the Standard Model are fixed in such a way that the total entropy at the late stage of the universe is maximized, which we call the maximum entropy ... More
Cyclic Universe à la string theoryApr 12 2005We shall present a model of the "cyclic universe" that can be constructed only by assuming a minimal set of properties of string theory. We clarify our viewpoint of the cyclic universe and show some attempts to mateliarize the idea as field theoretical ... More
Limiting Temperature, Limiting Curvature and the Cyclic UniverseJul 06 2003Jul 23 2003We propose a new type of cosmological model in which it is postulated that not only the temperature but also the curvature is limited by the mass scale of the Hagedorn temperature. We find that the big bang of this universe is smoothly connected to the ... More
Large N reduction on group manifoldsDec 08 2009Jul 30 2010We show that the large N reduction holds on group manifolds. Large N field theories defined on group manifolds are equivalent to some corresponding matrix models. For instance, gauge theories on S^3 can be regularized in a gauge invariant and SO(4) invariant ... More
A new mechanism of realizing inflationary universe with recourse to backreaction of quantized free fields -- Inflation without inflaton --Oct 02 2014Oct 31 2014It is shown that the inflationary era in early universe is realized due to the effect of backreaction of quantized matter fields. In fact we start by quantizing a free scalar field in the Friedmann-Robertson-Walker space-time, and the field is fluctuating ... More
Curved Superspaces and Local Supersymmetry in Supermatrix ModelFeb 21 2006May 09 2006In a previous paper, we introduced a new interpretation of matrix models, in which any d-dimensional curved space can be realized in terms of d matrices, and the diffeomorphism and the local Lorentz symmetries are included in the ordinary unitary symmetry ... More
Z2-vortex order of frustrated Heisenberg antiferromagnets in two dimensionsFeb 17 2011We discuss the recent experimental data on various frustrated quasi-two-dimensional Heisenberg antiferromagnets from the viewpoint of the Z2-vortex order, which include S=3/2 triangular-lattice antiferromagnet NaCrO2, S=1 triangular-lattice antiferromagnet ... More
Successive transitions and intermediate chiral phase in a superfuilid ^3He filmDec 22 1998Superfluidity ordering of thin ^3He films is studied by Monte Carlo simulations based on a two-dimensional lattice spin model with Z_2\times U(1)\times SO(3) symmetry. Successive phase transitions with an intermediate `chiral' phase, in which the l-vector ... More
Two models of spin glasses -- Ising versus HeisenbergMar 18 2010Brief review is given on recent numerical research of the ordering of two typical models of spin glasses (SGs), the three-dimensional (3D) Ising SG and the 3D Heisenberg SG models. Particular attention is paid to the questions of whether there is a thermodynamic ... More
Spin and Chirality Orderings of Frustrated Magnets -- Stacked-Triangular Antiferromagnets and Spin GlassesNov 05 2001``Chirality'' is a multispin quantity representing the sense or the handedness of the noncollinear spin structures induced by spin frustration. Recent studies have revealed that the chirality often plays an important role in the ordering of certain frustrated ... More
Spin-chirality decoupling in Heisenberg spin glasses and related systemsSep 26 2006Recent studies on the spin and the chirality orderings of the three-dimensional Heisenberg spin glass and related systems are reviewed with particular emphasis on the possible spin-chirality decoupling phenomena. Chirality scenario of real spin-glass ... More
Nature of the vortex-glass order in strongly type-II superconductorsFeb 14 2003Mar 14 2003The stability and the critical properties of the three-dimensional vortex-glass order in random type-II superconductors with point disorder is investigated in the unscreened limit based on a lattice {\it XY} model with a uniform field. By performing equilibrium ... More
Dynamical simulation of spin-glass and chiral-glass orderings in three-dimensional Heisenberg spin glassesMay 11 1998Spin-glass and chiral-glass orderings in three-dimensional Heisenberg spin glasses are studied with and without randaom magnetic anisotropy by dynamical Monte Carlo simulations. In isotropic case, clear evidence of a finite-temperature chiral-glass transition ... More
Fluctuation-dissipation ratio of the Heisenberg spin glassDec 25 2002Jun 10 2003Fluctuation-dissipation (FD) relation of the three-dimensional Heisenberg spin glass with weak random anisotropy is studied by off-equilibrium Monte Carlo simulation. Numerically determined FD ratio exhibits a ``one-step-ike''behavior, the effective temperature ... More
Dynamical Properties of Chiral-Glass Order in Ceramic High-Tc SuperconductorsDec 02 1999There recently accumulated growing numerical and experimental evidence that a novel glassy zero-field phase characterized by the spontaneously broken time-reversal symmetry, a chiral-glass phase, is realized in certain ceramic high-$T_c$ superconductors. ... More
Lagrangian self-similar solutions in gradient shrinking Kähler-Ricci solitonsMay 20 2015Jun 14 2016In this paper, we give a lower bound estimate for the diameter of a Lagrangian self-shrinker in a gradient shrinking K\"ahler-Ricci soliton as an analog of a result of A. Futaki, H. Li and X.-D. Li for a self-shrinker in a Euclidean space. We also prove ... More
Classical and quantum chiral order in frustrated XY magnetsFeb 07 2002Recent studies on the chiral order of regularly frustrated XY magnets are reviewed both in classical and quantum cases. In the classical case, chiral transition is a thermal one, while in the quantum case, it is a quantum phase transition. Importance ... More
Universality of phase transitions of frustrated antiferromagnetsMay 12 1998Recent theoretical and experimental studies on the critical properties of frustrated antiferromagnets with the noncollinear spin order, including stacked-triangular antiferromagnets and helimagnets, are reviewed. Particular emphasis is put on the novel ... More
Examples of Ricci-mean curvature flowsAug 17 2016Let $\pi:\mathbb{P}(\mathcal{O}(0)\oplus \mathcal{O}(k))\to \mathbb{P}^{n-1}$ be a projective bundle over $\mathbb{P}^{n-1}$ with $1\leq k \leq n-1$. In this paper, we show that lens space $L(k\, ;1)(r)$ with radius $r$ embedded in $\mathbb{P}(\mathcal{O}(0)\oplus ... More
Anomalous Hall effect as a probe of the chiral order in spin glassesOct 01 2002Dec 13 2002Anomalous Hall effect arising from the noncoplanar spin configuration (chirality) is discussed as a probe of the chiral order in spin glasses. It is shown that the Hall coefficient yields direct information about the linear and nonlinear chiral susceptibilities ... More
The ordering of XY spin glassesFeb 17 2011Ordering properties of XY-like spin-glass magnets with an easy-plane magnetic anisotropy are studied based on a symmetry consideration and the results of recent numerical simulations on the pure Heisenberg and XY spin-glass models. The effects of an easy-plane-type ... More
Spatiotemporal Correlations of EarthquakesMar 13 2006Statistical properties of earthquakes are studied both by the analysis of real earthquake catalog of Japan and by numerical computer simulations of the spring-block model in both one and two dimensions. Particular attention is paid to the spatiotemporal ... More
Simulation Studies on the Stability of the Vortex-Glass OrderJul 23 1999Dec 03 1999The stability of the three-dimensional vortex-glass order in random type-II superconductors with point disorder is investigated by equilibrium Monte Carlo simulations based on a lattice XY model with a uniform field threading the system. It is found that ... More
Chirality scenario of the spin-glass orderingJul 24 2009Jun 19 2010Detailed account is given of the chirality scenario of experimental spin-glass transitions. In this scenario, the spin glass order of weakly anisotropic Heisenberg-like spin-glass magnets including canonical spin glasses are essentially chirality driven. ... More
Several solutions of the Klein-Gordon equation in Kerr-Newman spacetime and the BSW effectJun 30 2016Jul 14 2016We investigate the radial part of the charged massive Klein-Gordon equation in Kerr-Newman spacetime, and in several specific situations, obtain several exact solutions in terms of essentially hypergeometric functions and their confluent type. Using these ... More
Ricci-mean curvature flows in gradient shrinking Ricci solitonsJan 26 2015Huisken studied asymptotic behavior of a mean curvature flow in a Euclidean space when it develops a singularity of type I, and proved that its rescaled flow converges to a self-shrinker in the Euclidean space. In this paper, we generalize this result ... More
Cosmological implications of Standard Model criticality and Higgs inflationSep 27 2017Apr 07 2018The observed Higgs mass indicates that the Standard Model can be valid up to near the Planck scale $M_\text{P}$. Within this framework, it is important to examine how little modification is necessary to fit the recent experimental results in particle ... More
Phase structure of the large-N reduced gauge theory and generalized Weingarten modelApr 10 2006Mar 19 2007We study a generalization of Weingarten model reduced to a point, which becomes the large-N reduced U(N) gauge theory in a special limit. We find that the U(1)^d symmetry is broken one by one, and restored simultaneously as U(1)^d -> U(1)^{d-1} -> ... ... More
Worldsheet Analysis of Gauge/Gravity DualitiesDec 08 2008Dec 29 2008Gauge/gravity dualities are investigated from the worldsheet point of view. In [arXiv:0706.1163] and [arXiv:0708.2463], a duality between 4d SYM and supergravity on AdS_5xS^5 has been partly explained by using an anisotropic scale invariance of worldsheet ... More
Field Equations of Massless Fields in the New Interpretation of the Matrix ModelNov 08 2006Recently, some of the authors have introduced a new interpretation of matrix models in which covariant derivatives on any curved space can be expressed by large-N matrices. It has been shown that the Einstein equation follows from the equation of motion ... More
Wilson Loops in Noncommutative Yang MillsOct 01 1999Oct 06 1999We study the correlation functions of the Wilson loops in noncommutative Yang-Mills theory based upon its equivalence to twisted reduced models. We point out that there is a crossover at the noncommutativity scale. At large momentum scale, the Wilson ... More
Universal description of viscoelasticity with foliation preserving diffeomorphismsJul 03 2009Sep 17 2009A universal description is proposed for generic viscoelastic systems with a single relaxation time. Foliation preserving diffeomorphisms are introduced as an underlying symmetry which naturally interpolates between the two extreme limits of elasticity ... More
Direct derivation of the Veneziano-Yankielowicz superpotential from matrix modelDec 20 2004Feb 16 2005We derive the Veneziano-Yankielowicz superpotential directly from the matrix model by fixing the measure precisely. The essential requirement here is that the effective superpotential of the matrix model corresponding to the ${\cal N}=4$ supersymmetric ... More
Possible origin of CMB temperature fluctuations: Vacuum fluctuations of Kaluza-Klein and string states during inflationary eraOct 25 2011May 12 2012We point out that the temperature fluctuations of cosmic microwave background (CMB) can be generated in a way that is different from the one usually assumed in slow-roll inflation. Our mechanism is based on vacuum fluctuations of fields which are at rest ... More
Meaning of prescriptions I and II in Higgs inflationOct 19 2016We consider the prescription dependence of the Higgs effective potential under the presence of general non-minimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure ... More
Universal description of viscoelasticity with foliation preserving diffeomorphismsApr 22 2010We review our recent proposal for a universal description of generic single-component viscoelastic systems with a single relaxation time. Foliation preserving diffeomorphisms are introduced as an underlying symmetry which naturally interpolates between ... More
Higgs inflation from Standard Model criticalityAug 21 2014Mar 20 2015The observed Higgs mass $M_H=125.9\pm0.4$GeV leads to the criticality of the Standard Model, that is, the Higgs potential becomes flat around the scale $10^{17\text{--}18}$GeV for the top mass $171.3$GeV. Earlier we have proposed a Higgs inflation scenario ... More
Back Reaction of 4D Conformal Fields on Static GeometryJul 30 2018Sep 16 2018Static, spherically symmetric solutions to the semi-classical Einstein equation are studied, including the effect of the quantum energy-momentum tensor for conformal matters with 4D Weyl anomaly. Through both perturbative and non-perturbative methods, ... More
Branched Polymer RevisitedSep 10 1999We show that correlation functions for branched polymers correspond to those for $\phi^3$ theory with a single mass insertion, not those for the $\phi^3$ theory themselves, as has been widely believed. In particular, the two-point function behaves as ... More
Massive higher spin fields in curved spacetime and necessity of non-minimal couplingsMay 11 2016Jun 30 2016Free massive higher spin fields in weak background gravitational fields are discussed. Contrary to the spin one case, higher spin fields should have nontrivial non-minimal couplings to the curvature. A precise analysis is given for the spin 2 case, and ... More
Higgs inflation still aliveMar 20 2014May 02 2014The observed value of the Higgs mass indicates that the Higgs potential becomes small and flat at the scale around $10^{17}$GeV. Having this fact in mind, we reconsider the Higgs inflation scenario proposed by Bezrukov and Shaposhnikov. It turns out that ... More
CMB Fluctuations and String Compactification ScalesMar 01 2011Dec 12 2011We propose a mechanism for the generation of temperature fluctuations of cosmic microwave background. We consider a large number of fields, such as Kaluza-Klein modes and string excitations. Each field contributes to the gravitational potential by a small ... More
Scaling Behaviors of Branched PolymersNov 01 1999We study the thermodynamic behavior of branched polymers. We first study random walks in order to clarify the thermodynamic relation between the canonical ensemble and the grand canonical ensemble. We then show that correlation functions for branched ... More
Supermatrix ModelsFeb 24 2001We investigate several matrix models based on super Lie algebras, osp(1|32,R), u(1|16,16) and gl(1|32,R). They are natural generalizations of IIB matrix model and were first proposed by Smolin. In particular, we study the supersymmetry structures of these ... More
Fuzzy Torus in Matrix ModelDec 27 2004We have calculated the free energy up to two loop to compare T^2 with T^4 in IIB matrix model. It turns out that T^2 has smaller free energy than T^4. We have also discussed the generation of the gauge group by considering k-coincident fuzzy tori and ... More
Meaning of the field dependence of the renormalization scale in Higgs inflationOct 19 2016May 24 2017We consider the prescription dependence of the Higgs effective potential under the presence of general nonminimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure ... More
Models of LHC Diphoton Excesses Valid up to the Planck scaleFeb 12 2016Jun 26 2016We discuss a possibility to explain the LHC diphoton excesses at $750$GeV by the new scalar $X$ that couples to the gauge bosons through the loop of new massive particles with Standard Model charges. We assume that the new particles decay into the Standard ... More
Ordering of the Heisenberg Spin Glass in High DimensionsNov 15 2002Jun 23 2003Ordering of the Heisenberg spin glass with the nearest-neighbor Gaussian coupling is investigated by equilibrium Monte Carlo simulations in four and five dimensions. Ordering of the mean-field Heisenberg spin-glass is also studied for comparison. Particular ... More
An $\varepsilon$-regularity theorem for line bundle mean curvature flowApr 04 2019Apr 17 2019In this paper, we study the line bundle mean curvature flow defined by Jacob and Yau. The line bundle mean curvature flow is a kind of parabolic flows to obtain deformed Hermitian Yang-Mills metrics on a given K\"ahler manifold. The goal of this paper ... More
Monte Carlo simulations of the three-dimensional XY spin glass focusing on the chiral and the spin orderDec 16 2012May 31 2013The ordering of the three-dimensional isotropic {\it XY} spin glass with the nearest-neighbor random Gaussian coupling is studied by extensive Monte Carlo simulations. To investigate the ordering of the spin and the chirality, we compute several independent ... More
Monte Carlo Studies of the Ordering of the Three-Dimensional Isotropic Heisenberg Spin Glass in Magnetic FieldsOct 11 2001Spin and chirality orderings of the three-dimensional Heisenberg spin glass under magnetic fields are studied by large-scale equilibrium Monte Carlo simulations. It is found that the chiral-glass transition and the chiral-glass ordered state, which are ... More
Spatiotemporal correlations of earthquakes in the continuum limit of the one-dimensional Burridge-Knopoff modelJul 29 2008Spatiotemporal correlations of the one-dimensional spring-block (Burridge-Knopoff) model of earthquakes, either with or without the viscosity term, are studied by means of numerical computer simulations. The continuum limit of the model is examined by ... More
Simulation study of earthquakes based on the two-dimensional Burridge-Knopoff model with the long-range interactionFeb 10 2008Jun 18 2008Spatiotemporal correlations of the two-dimensional spring-block (Burridge-Knopoff) models of earthquakes with the long-range inter-block interactions are extensively studied by means of numerical computer simulations. The long-range interaction derived ... More
Multi-task Learning for Japanese Predicate Argument Structure AnalysisApr 03 2019An event-noun is a noun that has an argument structure similar to a predicate. Recent works, including those considered state-of-the-art, ignore event-nouns or build a single model for solving both Japanese predicate argument structure analysis (PASA) ... More
Ordering of the Antiferromagnetic Heisenberg Model on a Pyrochlore SlabJan 10 2002Ordering of the geometrically frustrated two-dimensional Heisenberg antiferromagnet on a pyrochlore slab is studied by Monte Carlo simulations. The model is expected to serve as a reference system of SrCrGaO compound studied extensively. In sharp contrast ... More
Spin and chiral orderings of the antiferromagnetic XY model on the triangular lattice and their critical propertiesFeb 06 2012Feb 23 2012We study the antiferromagnetic {\it XY} model on a triangular lattice by extensive Monte Carlo simulations, focusing on its ordering and critical properties. Our result clearly shows that two separate transitions occur at two distinct temperatures, the ... More
Low-temperature magnetic properties of the Kondo lattice model in one dimensionSep 03 2014Mar 05 2015Low-temperature magnetic properties of the one-dimensional Kondo-lattice model with classical localized spins are investigated by means of a Monte Carlo simulation combined with an exact diagonalization technique. Comparative simulations are also made ... More