Results for "Teruaki Ikeda"

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Exact gravitational lensing by cosmic strings with junctionsJul 28 2008We point out that the results by Brandenberger et al. in Phys.Rev.D77:083502(2008) that the geometry around the straight cosmic strings with stationary junctions is flat to linear order in the string tension can be immediately extended to any order.
Instanton-noninstanton transition in nonintegrable tunneling processes: A renormalized perturbation approachMar 02 2015The instanton-noninstanton (I-NI) transition in the tunneling process, which has been numerically observed in classically nonintegrable quantum maps, can be described by a perturbation theory based on an integrable Hamiltonian renormalized so as to incorporate ... More
Loop contribution to inflationary magnetic fieldJan 07 2014Within the framework of the standard quantum electrodynamics, we compute contribution of vacuum polarization at one-loop order to the power spectrum of the magnetic field on inflationary (de Sitter) background. It is found that the one-loop term exhibits ... More
Third order equations of motion and the Ostrogradsky instabilityNov 13 2014Apr 15 2015It is known that any nondegenerate Lagrangian containing time derivative terms higher than first order suffers from the Ostrogradsky instability, pathological excitation of positive and negative energy degrees of freedom. We show that, within the framework ... More
Self-accelerating solutions in massive gravity on an isotropic reference metricAug 15 2012Oct 12 2012Within the framework of the recently proposed ghost-free massive gravity, a cosmological constant-type self-accelerating solution has been obtained for Minkowski and de Sitter reference metrics. We ease the assumption on the reference metric and find ... More
Black hole perturbation in parity violating gravitational theoriesJul 19 2011Dec 14 2011We study linear perturbations around the static and spherically symmetric spacetime for the gravitational theories whose Lagrangian depends on Ricci scalar and the parity violating Chern-Simons term. By an explicit construction, we show that Hamiltonian ... More
Statistics of general functions of a Gaussian field -application to non-Gaussianity from preheating-Mar 06 2013May 22 2013We provide a general formula for calculating correlators of arbitrary function of a Gaussian field. This work extends the standard leading-order approximation based on the delta N formalism to the case where truncation of the delta N at some low order ... More
Evolution of FLRW spacetime after the birth of a cosmic stringDec 12 2011May 01 2012We consider the evolution of an initially FLRW universe after the formation of a long, straight, cosmic string with arbitrary tension and mass per unit length. The birth of the string sources scalar and tensor-type perturbations in the background metric ... More
Primordial black holes as a novel probe of primordial gravitational waves. II: Detailed analysisMay 15 2016Aug 16 2016Recently we have proposed a novel method to probe primordial gravitational waves from upper bounds on the abundance of primordial black holes (PBHs). When the amplitude of primordial tensor perturbations generated in the early Universe is fairly large, ... More
Primordial black holes as a novel probe of primordial gravitational wavesJun 17 2015May 15 2016We propose a novel method to probe primordial gravitational waves by means of primordial black holes (PBHs). When the amplitude of primordial tensor perturbations on comoving scales much smaller than those relevant to Cosmic Microwave Background is very ... More
Constraining Primordial Magnetic Fields by CMB Photon-Graviton ConversionSep 02 2013We revisit the method of using the photon-graviton conversion mechanism in the presence of the external magnetic field to probe small-scale primordial magnetic fields that may exist between the last scattering surface and present. Specifically, we investigate ... More
Nucleon described by the chiral soliton in the chiral quark soliton modelJun 23 1997We give a survey of recent development and applications of the chiral quark soliton model (also called the Nambu-Jona-Lasinio soliton model) with $N_f$=2 and $N_f$=3 quark flavors for the structure of baryons. The model is an effective chiral quark model ... More
Non-Gaussianity from SymmetryApr 02 2008Sep 01 2008We point out that a light scalar field fluctuating around a symmetry-enhaced point can generate large non-Gaussianity in density fluctuations. We name such a particle as an "ungaussiton", a scalar field dominantly produced by the quantum fluctuations,generating ... More
Finiteness of the image of the Reidemeister torsion of a spliceApr 04 2019The set $\mathit{RT}(M)$ of values of the $\mathit{SL}(2,\mathbb{C})$-Reidemeister torsion of a 3-manifold $M$ can be both finite and infinite. We prove that $\mathit{RT}(M)$ is a finite set if $M$ is the splice of two certain knots in the 3-sphere. The ... More
A Heuristic Method of Generating Diameter 3 Graphs for Order/Degree ProblemSep 11 2016We propose a heuristic method that generates a graph for order/degree problem. Target graphs of our heuristics have large order (> 4000) and diameter 3. We describe the ob- servation of smaller graphs and basic structure of our heuristics. We also explain ... More
Linear perturbation analysis of hairy black holes in shift-symmetric Horndeski theories I: odd-parity perturbationsOct 03 2016We analyze the mode stability of odd-parity perturbations of black holes with linearly time-dependent scalar hair in shift-symmetric Horndeski theories. We show that a large class of black-hole solutions in these theories suffer from ghost or gradient ... More
Black hole perturbation in nondynamical and dynamical Chern-Simons gravityOct 28 2011Oct 12 2012Chern-Simons gravitational theories are extensions of general relativity in which the parity is violated due to the Chern-Simons term. We study linear perturbations on the static and spherically symmetric background spacetime both for nondynamical and ... More
Extension of local-type inequality for the higher order correlation functionsMay 30 2011May 31 2011For the local-type primordial perturbation, it is known that there is an inequality between the bispectrum and the trispectrum. By using the diagrammatic method, we develop a general formalism to systematically construct the similar inequalities up to ... More
Twisted Alexander polynomials and a partial order on the set of prime knotsApr 05 2009We give a survey of some recent papers by the authors and Masaaki Wada relating the twisted Alexander polynomial with a partial order on the set of prime knots. We also give examples and pose open problems.
DNA as a one-dimensional chiral material. II. Dynamics of the structural transition between B form and Z formOct 11 2012We analyze the dynamics of structural transitions between normal right-handed B form and unusual left-handed Z form for a linear DNA molecule. The dynamics under the external torque in physiological buffer is modeled by a Langevin equation, with the potential ... More
Curvature perturbation from velocity modulationJul 15 2011Sep 08 2011We propose a new variant model of the modulated reheating. If particles have large scale fluctuations on their velocities, or equivalently their Lorentz factors, the decay rate also fluctuates and the curvature perturbation is induced via their decay ... More
Detecting cosmic string passage through the Earth by consequent global earthquakeMay 29 2013Effects invoked by the passage of the cosmic string through the Earth are investigated. The cosmic string induces global oscillations of the Earth whose amplitude and acceleration both linearly depend on the string line density. For the line density maximally ... More
Majorana and Majorana-Weyl fermions in lattice gauge theoryJun 16 2004Aug 11 2004In various dimensional Euclidean lattice gauge theories, we examine a compatibility of the Majorana decomposition and the charge conjugation property of lattice Dirac operators. In $8n$ and $1+8n$ dimensions, we find a difficulty to decompose a classical ... More
$L^2$-torsion invariants and the Magnus representation of the mapping class groupJan 29 2008In this paper, we study a series of $L^2$-torsion invariants from the viewpoint of the mapping class group of a surface. We establish some vanishing theorems for them. Moreover we explicitly calculate the first two invariants and compare them with hyperbolic ... More
The decoupling of the glass transitions in the two-component $p$-spin spherical modelMar 21 2016Binary mixtures of large and small particles with disparate size ratio exhibit a rich phenomenology at their glass transition points. In order to gain insights on such systems, we introduce and study a two-component version of the $p$-spin spherical spin ... More
One-dimensional Kac model of dense amorphous hard spheresMay 28 2015We introduce a new model of hard spheres under confinement for the study of the glass and jamming transitions. The model is an one-dimensional chain of the $d$-dimensional boxes each of which contains the same number of hard spheres, and the particles ... More
Scalar mode propagation in modified gravity with a scalar fieldJul 30 2009We study the propagation of the scalar modes around a Friedmann-Lemaitre-Robertson-Walker universe for general modifications of gravity in the presence of a real scalar field. In general, there will be two propagating scalar perturbation fields, which ... More
Linear growth of matter density perturbations in f(R,G) theoriesOct 19 2010May 12 2011We derive the equation of matter density perturbations on sub-horizon scales around a flat Friedmann-Lema\^\i tre-Robertson-Walker background for the general Lagrangian density $f(R,\GB)$ that is a function of a Ricci scalar $R$ and a Gauss-Bonnet term ... More
Vacuum structure for scalar cosmological perturbations in Modified Gravity ModelsApr 14 2009Jun 30 2009We have found for the general class of Modified Gravity Models f(R,G) a new instability which can arise in vacuum for the scalar modes of the cosmological perturbations if the background is not de Sitter. In particular, the short-wavelength modes, if ... More
Temporal enhancement of super-horizon curvature perturbations from decays of two curvatons and its cosmological consequencesJun 29 2011Aug 07 2011If more than one curvaton dominate the Universe at different epochs from each other, curvature perturbations can be temporarily enhanced to a value much larger than the observed one 10^{-5}. The traces of the enhancement may be left as higher order correlation ... More
Metric perturbation from inflationary magnetic field and generic bound on inflation modelsApr 18 2012There is an observational indication of extragalactic magnetic fields. No known astrophysical process can explain the origin of such large scale magnetic fields, which motivates us to look for their origin in primordial inflation. By solving the linearized ... More
Deformation of BF theories, Topological Open Membrane and A Generalization of The Star DeformationMay 29 2001Aug 14 2001We consider a deformation of the BF theory in any dimension by means of the antifield BRST formalism. Possible consistent interaction terms for the action and the gauge symmetries are analyzed and we find a new class of topological gauge theories. Deformations ... More
Two-Dimensional Gravity and Nonlinear Gauge TheoryDec 08 1993We review nonlinear gauge theory and its application to two-dimensional gravity. We construct a gauge theory based on nonlinear Lie algebras, which is an extension of the usual gauge theory based on Lie algebras. It is a new approach to generalization ... More
Power Grid with 100% Renewable Energy for Small Island Developing States -- Nexus of Energy, Environment, and Economic GrowthApr 09 2019We estimated system-wise levelized cost of electricity (LCOE) for a power grid with a high level of renewable energy using our grid optimization model. The estimation results of the system-wise LCOE are discussed in terms of the nexus of energy, environment, ... More
Quantum Resistive Behaviors in the Vortex Liquid Regimes at Finite TemperaturesOct 29 2002Sep 02 2003Motivated by a {\it mean field-like} resistive behavior in magnetic fields commonly seen in various superconducting (SC) cuprates and organics with strong fluctuation, {\it quantum} SC fluctuation effects on resistive behaviors are reexamined by putting ... More
Ginzburg-Landau Theory of Vortex Phase Diagram in Layered Type II SuperconductorMay 07 2001Recent theoretical understanding of the vortex phase diagram in real layered type II superconductors is briefly described in both cases with fields perpendicular (B \parallel c) and parallel (B \perp c) to the superconducting layers. The description is ... More
Quantum Resistive Transition in Type II Superconductors under Magnetic FieldJun 16 1995It is shown that, within a Ginzburg-Landau (GL) formalism, the superconducting fluctuation is insulating at zero temperature even if the fluctuation dynamics is metallic (dissipative). Based on this fact, the low temperature behavior of the $H_{c2}$-line ... More
Deformation of Batalin-Vilkovisky StructuresApr 07 2006Aug 22 2006A Batalin-Vilkovisky formalism is most general framework to construct consistent quantum field theories. Its mathematical structure is called {\it a Batalin-Vilkovisky structure}. First we explain rather mathematical setting of a Batalin-Vilkovisky formalism. ... More
High field superconducting phase diagrams including Fulde-Ferrell-Larkin-Ovchinnikov vortex statesJun 03 2007Sep 08 2007Motivated by a striking observation of a Fulde-Ferell-Larkin-Ovchinnikov (FFLO) vortex state in the heavy fermion material CeCoIn5 in fields {\it perpendicular} to the superconducting planes (${\bf H} \parallel c$), superconducting phase diagrams including ... More
Impurity-induced broadening of the transition to a Fulde-Ferrell-Larkin-Ovchinnikov phaseDec 02 2009Mar 04 2010Recent study on doping effects in the heavy fermion superconductor CeCoIn$_5$ has shown that a small amount of doping induces unexpectedly large broadening of the second order transition into the high field and low temperature (HFLT) phase of this material. ... More
Superconducting transition in disordered granular superconductors in magnetic fieldsOct 14 2005Jul 28 2006Motivated by a recent argument that the superconducting (SC) transition field of three-dimensional (3D) disordered superconductors with granular structure in a nonzero magnetic field should lie above $H_{c2}(0)$ in low $T$ limit, the glass transition ... More
Hydrodynamics and Nonlocal Conductivities in Vortex States of Type II SuperconductorsJul 25 1995A hydrodynamical description for vortex states in type II superconductors is presented based on the time-dependent Ginzburg-Landau equation (TDGL). In contrast to the familiar extension of a single vortex dynamics based on the force balance, our description ... More
Hydrodynamics and Nonlocal Conductivities in Vortex StatesFeb 24 1995A hydrodynamical description for vortex states in type II superconductors with no pinning is presented based on the time-dependent GL equation, and the nonlocal conductivities are examined in terms of Kubo formula. Typically, the nonlocal conductivities ... More
Donaldson Invariants and Their Generalizations from AKSZ Topological Field TheoriesApr 12 2011Observable structures of a topological field theory of AKSZ type are analyzed. From a double (or multiple) complex structure of observable algebras, new topological invariants are constructed. Especially, Donaldson polynomial invariants and their generalizations ... More
Chern-Simons Gauge Theory coupled with BF TheoryMar 06 2002Jul 31 2002We couple three-dimensional Chern-Simons gauge theory with BF theory and study deformations of the theory by means of the antifield BRST formalism. We analyze all possible consistent interaction terms for the action under physical requirements and find ... More
Three Dimensional Topological Field Theory induced from Generalized Complex StructureDec 14 2004Mar 21 2005We construct a three-dimensional topological sigma model which is induced from a generalized complex structure on a target generalized complex manifold. This model is constructed from maps from a three-dimensional manifold $X$ to an arbitrary generalized ... More
The Exact Solution of Born-Infeld Theory in Two DimensionJul 03 1997We obtain the exact operator solution of two-dimensional quantum Born-Infeld theory. This theory has a Lagrangian density non-polynomial in the fundamental fields. So this analysis might shed some light on the analysis of non-perturbative effects of field ... More
Lifespan of solutions for the nonlinear Schrödinger equation without gauge invarianceNov 29 2012Dec 06 2012We study the lifespan of solutions for the nonlinear Schr\"odinger equation id_{t}u+{\Delta}u={\lambda}|u|^{p}, (t,x)\in[0,T)\timesR^{n}, with the initial condition, where 1<p\leq 1+2/n and {\lambda}\in C. Our main aim in this paper is to prove an upper ... More
Dressed Quark Propagator at Finite Temperature in the Schwinger-Dyson approach with the Rainbow Approximation - exact numerical solutions and their physical implicationJul 10 2001The Schwinger-Dyson equation for the quark in the rainbow approximation at finite temperature (T) is solved numerically without introducing any ansatz for the dressed quark propagator. The dymanical quark mass-function and the wave-function renormalization ... More
Absence of Quantum Metallic Behavior in Disordered Granular SuperconductorsJul 23 2003We examine the idea, postulated by Phillips et al., that a finite resistivity in $T \to 0$ limit in disordered granular superconducting (SC) films is explained as a consequence of the absence of phase stiffness in a phase glass (PG) peculiar to granular ... More
Fluctuation Effects in Underdoped Cuprate Superconductors under Magnetic FieldMar 11 2002Aug 30 2002Fluctuation effects in underdoped cuprates under high fields are examined by trying to fit theoretical results to resistivity and Nernst data in vortex states. The superconducting (SC) fluctuation in underdoped cuprates includes not only the ordinary ... More
Comment on "Disorder and Quantum Fluctuations in Superconducting Films in Strong Magnetic Fields"Nov 07 2001Sep 03 2002This is a Comment to the paper by Galitski and Larkin in Phys. Rev. Lett. 87 (2001) 087001 (cond-mat/0104247). It is pointed out that their argument that the quantumn glass transition field should be higher than the mean field H_{c2}(0) is incompatible ... More
Josephson Vortex States in Intermediate FieldsOct 10 2001Dec 03 2001Motivated by recent resistance data in high $T_c$ superconductors in fields {\it parallel} to the CuO layers, we address two issues on the Josephson-vortex phase diagram, the appearances of structural transitions on the observed first order transition ... More
Photon stimulated desorption of and nuclear resonant scattering by noble gas atoms at solid surfacesJan 18 2015Apr 20 2015When a noble gas atom approaches a solid surface, it is adsorbed via the Van der Waals force, which is called physisorption. In this thesis, several experimental results concerning physisorbed atoms at surfaces are presented. First, photon stimulated ... More
Bielliptic curves of genus three and the Torelli problem for certain elliptic surfacesJan 24 2017We study the Hodge structure of elliptic surfaces which are canonically defined from bielliptic curves of genus three. We prove that the period map for the second cohomology has one dimensional fibers, and the period map for the total cohomology is of ... More
Bees with attitude: the effect of gusts on flight dynamicsFeb 10 2018Flight is a complicated task at small scales in part due to the ubiquitous unsteady air which contains it. Flying organisms deal with these difficulties using active and passive control mechanisms to steer their body motion. Body attitudes of flapping ... More
Topological Field Theories and Geometry of Batalin-Vilkovisky AlgebrasSep 05 2002Oct 31 2002The algebraic and geometric structures of deformations are analyzed concerning topological field theories of Schwarz type by means of the Batalin-Vilkovisky formalism. Deformations of the Chern-Simons-BF theory in three dimensions induces the Courant ... More
A Deformation of Three Dimensional BF TheoryOct 12 2000Feb 20 2001We consider a deformation of three dimensional BF theory by means of the antifield BRST formalism. Possible deformations for the action and the gauge symmetries are analyzed. We find a new class of gauge theories which include nonabelian BF theory, higher ... More
How to Solve Quantum Nonlinear Abelian Gauge Theory in Two Dimension in the Heisenberg PictureApr 07 1998The new method based on the operator formalism proposed by Abe and Nakanishi is applied to the quantum nonlinear abelian gauge theory in two dimension. The soluble models in this method are extended to wider class of quantum field theories. We obtain ... More
Anisotropic Strong Coupling Effects on Superfluid 3He in Aerogels - Conventional Spin-Fluctuation Approach -Jan 05 2015Motivated by recent experiments on liquid $^3$He reporting emergence of novel superfluid phases in globally anisotropic aerogels, our previous theory on superfluid $^3$He in globally anisotropic aerogels is extended to incorporate effects of an anisotropy ... More
Stability of vortex state of Fulde-Ferrell-Larkin-Ovchinnikov type in magnetic fields perpendicular to superconducting layersOct 31 2006Motivated by recent NMR data suggesting the presence of a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) vortex lattice in magnetic fields perpendicular to the superconducting plane in the heavy-fermion superconductor CeCoIn5, we examine here the stability of ... More
Conductivity in glass phases of disordered granular superconductors in magnetic fieldsJun 20 2006Jun 08 2009The electric conductivities in glass phases of three-dimensional (3D) granular superconductors in magnetic fields are examined based on a quantum disordered Josephson-junction array. A correct inclusion of the Ohmic dissipative dynamics leads to glass ... More
Vortex tilt modulus in Fulde-Ferrell-Larkin-Ovchinnikov stateOct 28 2006Jul 27 2007Vortex tilt response in Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) vortex lattice is theoretically examined as a probe reflecting the spatial structure of this state. In the FFLO state with nodal planes perpendicular to the magnetic field in a quasi 2D material ... More
Comment on "History Effects and Phase Diagram near the Lower Critical Point in YBa_2Cu_3O_{7-δ} Single Crystals"Jan 17 2002This is a Comment on an experimental paper by Zhukov et al. on the issue of a lower critical point, seen only in YBCO clean samples, of the first order transition line implying a vortex liquid-freezing. An explanation with a firm theoretical basis of ... More
Stability conditions on $\text{CY}_N$ categories associated to $A_n$-quivers and period mapsMay 21 2014In this paper, we study the space of stability conditions on a certain $N$-Calabi-Yau ($\text{CY}_N$) category associated to an $A_n$-quiver. Recently, Bridgeland and Smith constructed stability conditions on some $\text{CY}_3$ categories from meromorphic ... More
Schubert classes in the equivariant cohomology of the Lagrangian GrassmannianAug 05 2005May 11 2006Let $LG_n$ denote the Lagrangian Grassmannian parametrizing maximal isotropic (Lagrangian) subspaces of a fixed symplectic vector space of dimension $2n.$ For each strict partition $\lambda=(\lambda_1,...,\lambda_k)$ with $\lambda_1\leq n$ there is a ... More
The effect of memory on relaxation in a scalar field theoryJan 09 2004We derive a kinetic equation with a non-Markovian collision term which includes a memory effect, from Kadanoff-Baym equations in $\phi^4$ theory within the three-loop level for the two-particle irreducible (2PI) effective action. The memory effect is ... More
A new construction of the real numbers by alternating seriesAug 07 2012Oct 30 2013We put forward a new method of constructing the complete ordered field of real numbers from the ordered field of rational numbers. Our method is a generalization of that of A. Knopfmacher and J. Knopfmacher. Our result implies that there exist infinitely ... More
On the functional equation of the Siegel seriesJun 03 2015It is well-known that the Fourier coefficients of Siegel-Eisenstein series can be expressed in terms of the Siegel series. The functional equation of the Siegel series of a quadratic form over $\mathbb{Q}_p$ was first proved by Katsurada. In this paper, ... More
The double cover of cubic surfaces branched along their HessianDec 20 2010We prove the relation between the Hodge structure of the double cover of a nonsingular cubic surface branched along its Hessian and the Hodge structure of the triple cover of the ambient projective space branched along the cubic surface. And we introduce ... More
The effects of the kaonic cloud on the neutron electric form factorJul 17 1995Mar 11 1997We investigate the effects of mesonic clouds on neutron electric and nucleon strange form factors in the framework of the chiral quark soliton model. We present a mechanism to identify the mesonic clouds and their Yukawa tail in the polarized Dirac sea. ... More
Black hole perturbation in the most general scalar-tensor theory with second-order field equations II: the even-parity sectorFeb 26 2014Nov 18 2014We perform a fully relativistic analysis of even-parity linear perturbations around a static and spherically symmetric solution in the most general scalar-tensor theory with second-order field equations. This paper is a sequel to Kobayashi {\em et al.} ... More
The Suzaku Discovery of A Hard Power-Law Component in the Spectra of Short Bursts from SGR 0501+4516Jun 24 2011Using data with the Suzaku XIS and HXD, spectral studies of short bursts from the soft gamma repeater SGR 0501+4516 were performed. In total, 32 bursts were detected during the ~60 ks of observation conducted in the 2008 August activity. Excluding the ... More
CMB temperature trispectrum of cosmic stringsNov 06 2009Feb 22 2010We provide an analytical expression for the trispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by cosmic strings. Our result is derived for the small angular scales under the assumption that the temperature anisotropy ... More
A Large Mass Hierarchy from a Small Non-minimal CouplingMar 08 2019We propose a simple but novel cosmological scenario where both the Planck mass and the dark energy scale emerge from the same super-Hubble quantum fluctuations of a non-minimally coupled ultra-light scalar field during primordial inflation. The current ... More
Scattering of Gravitational Waves by the Weak Gravitational Fields of Lens ObjectsMar 16 2005Jun 08 2005We consider the scattering of the gravitational waves by the weak gravitational fields of lens objects. We obtain the scattered gravitational waveform by treating the gravitational potential of the lens to first order, i.e. using the Born approximation. ... More
Fundamental theorem on gauge fixing at the action levelJul 30 2016Regardless of the long history of gauge theories, it is not well-recognized under which condition gauge fixing at the action level is legitimate. We address this issue from the Lagrangian point of view, and prove the following theorem on the relation ... More
Primordial Non-Gaussianity in Multi-Scalar InflationNov 19 2007Jan 10 2013We give a concise formula for the non-Gaussianity of the primordial curvature perturbation generated on super-horizon scales in multi-scalar inflation model without assuming slow-roll conditions. This is an extension of our previous work. Using this formula, ... More
Quantum Optics in Dispersive and Absorptive MediaApr 11 1998Using microscopic models in which both photons and excitons are treated as microscopic degrees of freedom, we discuss polaritons of two cases: One is the case when excitonic parameters are time dependent. The time dependence causes creation of polaritons ... More
Reheating the Universe Once More: The Dissipation of Acoustic Waves as a Novel Probe of Primordial Inhomogeneities on Even Smaller ScalesMar 21 2014Aug 08 2014We provide a simple but robust bound on the primordial curvature perturbation in the range $10^4 {\rm Mpc}^{-1} < k < 10^5 {\rm Mpc}^{-1}$, which has not been constrained so far unlike low wavenumber modes. Perturbations on these scales dissipate the ... More
Magneto-reheating constraints from curvature perturbationsFeb 25 2013As additional perturbative degrees of freedom, it is known that magnetic fields of inflationary origin can source curvature perturbations on super-Hubble scales. By requiring the magnetic generated curvature to remain smaller than its inflationary adiabatic ... More
Twisted Alexander polynomials and surjectivity of a group homomorphismOct 11 2005If phi: G-->G' is a surjective homomorphism, we prove that the twisted Alexander polynomial of G is divisible by the twisted Alexander polynomial of G'. As an application, we show non-existence of surjective homomorphism between certain knot groups.
Strange vector form factors of the nucleon in the SU(3) chiral quark-soliton model with the proper kaonic cloudJun 26 1996The strange vector form factors are evaluated in the range between $Q^2=0$ and $Q^2=1\ \mbox{GeV}^2$ in the framework of the SU(3) chiral quark-soliton model (or semi-bosonized SU(3) Nambu-Jona-Lasinio model). The rotational $1/N_c$ and $m_s$ corrections ... More
Tangled String for Multi-Scale Explanation of Contextual Shifts in Stock MarketJan 28 2019The original research question here is given by marketers in general, i.e., how to explain the changes in the desired timescale of the market. Tangled String, a sequence visualization tool based on the metaphor where contexts in a sequence are compared ... More
Ghost-free theories with arbitrary higher-order time derivativesApr 21 2018Jul 03 2018We construct no-ghost theories of analytic mechanics involving arbitrary higher-order derivatives in Lagrangian. It has been known that for theories involving at most second-order time derivatives in the Lagrangian, eliminating linear dependence of canonical ... More
Axial anomaly in the reduced model: Higher representationsSep 15 2003The topological charge in the $\U(N)$ vector-like reduced model can be defined by using the overlap Dirac operator. We obtain its large $N$ limit for a fermion in a general gauge-group representation under a certain restriction of gauge field configurations ... More
Axial anomaly in the reduced model: Higher representationsMay 13 2003May 18 2003The axial anomaly arising from the fermion sector of $\U(N)$ or $\SU(N)$ reduced model is studied under a certain restriction of gauge field configurations (the ``$\U(1)$ embedding'' with $N=L^d$). We use the overlap-Dirac operator and consider how the ... More
Supermassive black holes formed by direct collapse of inflationary perturbationsSep 08 2016We propose a mechanism of producing a new type of primordial perturbations which collapse to primordial black holes whose mass can be as large as necessary for them to grow to the supermassive black holes observed at high redshifts, without contradicting ... More
Update of the stranger story: The strange vector form factors of the nucleon in the SU(3) chiral quark-soliton modelJun 16 1995Mar 18 1996The strange vector form factors are evaluated for $Q^2=0$ and $Q^2=1\ \mbox{GeV}^2$ in the framework of the SU(3) chiral quark-soliton model (or semi-bosonized SU(3) Nambu-Jona-Lasinio model). The rotational $1/N_c$ and $m_s$ corrections are taken into ... More
Consequences of a stochastic approach to the conformal invariance of inflationary correlatorsOct 09 2012Oct 16 2012We provide a general formalism to calculate the infrared correlators of multiple interacting scalar fields in the de Sitter space by means of the stochastic approach. These scalar fields are treated as test fields and hence our result is applicable to ... More
Universal instability of hairy black holes in Lovelock-Galileon theories in D dimensionsNov 19 2015Mar 30 2016We analyze spherically symmetric black hole solutions with time-dependent scalar hair in a class of Lovelock-Galileon theories, which are the scalar-tensor theories with second-order field equations in arbitrary dimensions. We first show that known black ... More
Instability of hairy black holes in shift-symmetric Horndeski theoriesOct 26 2015Sep 11 2016Recently it was pointed out that in shift-symmetric scalar-tensor theories a black hole can have nontrivial scalar hair which depends linearly on time. We develop black hole perturbation theory for such solutions and compute the quadratic action of odd-parity ... More
Black hole perturbation in the most general scalar-tensor theory with second-order field equations I: The odd-parity sectorFeb 22 2012Nov 14 2017We perform a fully relativistic analysis of odd-type linear perturbations around a static and spherically symmetric solution in the most general scalar-tensor theory with second-order field equations in four-dimensional spacetime. It is shown that, as ... More
Twisted Alexander polynomials of torus linksApr 17 2019In this paper we give an explicit formula for the twisted Alexander polynomial of any torus link and show that it is a locally constant function on the $SL(2, \mathbb C)$-character variety. We also discuss similar things for the higher dimensional twisted ... More
A note on the replica liquid theory of binary mixturesSep 27 2016It has been known that the binary replica liquid theory (RLT) is inconsistent with its one-component counterpart; In the limit that all atoms are identical, the configurational entropy and thus the glass transition point calculated by the binary RLT differ ... More
Note: A replica liquid theory of binary mixturesSep 27 2016Dec 08 2016It has been known that the binary replica liquid theory (RLT) is inconsistent with its one-component counterpart; In the limit that all atoms are identical, the configurational entropy and thus the glass transition point calculated by the binary RLT differ ... More
Thermodynamics and Structural Properties of the High Density Gaussian Core ModelApr 18 2011Jul 20 2011We numerically study thermodynamic and structural properties of the one-component Gaussian core model (GCM) at very high densities. The solid-fluid phase boundary is carefully determined. We find that the density dependence of both the freezing and melting ... More
Ikeda and Miyazaki Reply to Rolf Schilling and Bernhard Schmid [arXiv:1101.5577]Jan 31 2011Reply to the preceding comment by Rolf Schilling and Bernhard Schmid [arXiv:1101.5577, Phys. Rev. Lett. 106, 049601 (2011)].
Explicit formula for the Siegel series of a half-integral matrix over the ring of integers in a non-archimedian local fieldFeb 22 2016Let F be a non-archimedian local field of characteristic 0, and O the ring of integres in F. We give an explicit formula for the Siegel series of a half-integral matrix over O. This formula expresses the Siegel series of a half-integral matrix $B$ explicitly ... More