Results for "Takashi Toma"

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Effect of Degenerate Particles on Internal Bremsstrahlung of Majorana Dark MatterNov 18 2014Sep 21 2015Gamma-rays induced by annihilation or decay of dark matter can be its smoking gun signature. In particular, gamma-rays generated by internal bremsstrahlung of Majorana and real scalar dark matter is promising since it can be a leading emission of sharp ... More
Radiative Lepton Model and Dark Matter with Global $U(1)'$ SymmetryJan 27 2014Mar 12 2014We propose a radiative lepton model, in which the charged lepton masses are generated at one-loop level, and the neutrino masses are induced at two-loop level. On the other hand, tau mass is derived at tree level since it is too heavy to generate radiatively. ... More
A new mechanism of sterile neutrino dark matter productionFeb 08 2018Jul 20 2018We consider a scenario where the dark matter candidate is a sterile neutrino with sizable self-interactions, described by a dimension-six operator, and with negligible interactions with the Standard Model. The relic abundance is set by the freeze-out ... More
Probing pseudo-Goldstone dark matter at the LHCDec 14 2018Pseudo-Goldstone dark matter coupled to the Standard Model via the Higgs portal offers an attractive framework for phenomenologically viable pseudo-scalar dark matter. It enjoys natural suppression of the direct detection rate due to the vanishing of ... More
A Model of Neutrino Mass and Dark Matter with an Accidental SymmetryApr 22 2015Nov 08 2015We present a model of radiative neutrino mass that automatically contains an accidental $Z_2$ symmetry and thus provides a stable dark matter candidate. This allows a common framework for the origin of neutrino mass and dark matter without invoking any ... More
Can A Higgs Portal Dark Matter be Compatible with the Anti-proton Cosmic-ray?Mar 14 2012Jun 05 2012Recent direct detection experiments of Dark Matter (DM), CoGeNT and DAMA implicate a light DM of a few GeV. Such a light DM would generate a large amount of anti-proton since suppression for anti-proton flux from DM annihilation is ineffective. We discuss ... More
Implications of Two-component Dark Matter Induced by Forbidden Channels and Thermal Freeze-outNov 21 2016We consider a model of two-component dark matter based on a hidden $U(1)_D$ symmetry, in which relic densities of the dark matter are determined by forbidden channels and thermal freeze-out. The hidden $U(1)_D$ symmetry is spontaneously broken to a residual ... More
X-ray lines and self-interacting dark matterJun 05 2015Dec 03 2015We study the correlation between a monochromatic signal from annihilating dark matter and its self-interacting cross section. We apply our argument to a complex scalar dark sector, where the pseudo-scalar plays the role of a warm dark matter candidate ... More
3.55 keV X-ray Line Signal from Excited Dark Matter in Radiative Neutrino ModelApr 18 2014Sep 03 2014We study an exciting dark matter scenario in a radiative neutrino model to explain the X-ray line signal at $3.55$ keV recently reported by XMN-Newton X-ray observatory using data of various galaxy clusters and Andromeda galaxy. We show that the required ... More
Boosted Self-interacting Dark Matter in a Multi-component Dark Matter ModelJun 24 2018Oct 15 2018In models of multi-component dark matter, the lighter component of dark matter can be boosted by annihilations of the heavier state if mass splitting is large enough. Such relativistic dark matter can be detectable via large neutrino detectors such as ... More
Electric Dipole Moments of Charged Leptons with Sterile FermionsNov 10 2015Mar 04 2016We address the impact of sterile fermions on charged lepton electric dipole moments. Any experimental signal of these observables calls for scenarios of physics beyond the Standard Model providing new sources of CP violation. In this work, we consider ... More
Electric dipole moments of charged leptons with sterile fermionsNov 10 2016We address the impact of sterile fermions on charged lepton electric dipole moments. We show that in order to have a non-vanishing contribution to electric dipole moments, the minimal extension necessitates the addition of at least two sterile fermion ... More
Lepton Flavor Violation in the Scotogenic ModelDec 10 2013Jan 28 2014We investigate lepton flavor violation in the scotogenic model proposed by Ma in which neutrinos acquire non-zero masses at the 1-loop level. Although some works exist in this direction, they have mainly focused on the radiative decay $\ell_\alpha \to ... More
Electric Dipole Moments in the Minimal Scotogenic ModelJan 31 2018Apr 08 2018In this work we consider a minimal version of the scotogenic model capable of accounting for an electron electric dipole moment within experimental sensitivity reach in addition to providing a dark matter candidate and radiatively generating neutrino ... More
Electron electric dipole moment in Inverse Seesaw modelsMay 24 2016Aug 01 2016We consider the contribution of sterile neutrinos to the electric dipole moment of charged leptons in the most minimal realisation of the Inverse Seesaw mechanism, in which the Standard Model is extended by two right-handed neutrinos and two sterile fermion ... More
Fermionic Dark Matter in Radiative Inverse Seesaw Model with U(1)_{B-L}Jul 04 2012Aug 09 2012We construct a radiative inverse seesaw model with local B-L symmetry, and investigate the flavor structure of the lepton sector and the fermionic Dark Matter. Neutrino masses are radiatively generated through a kind of inverse seesaw framework. The PMNS ... More
Probing pseudo Nambu-Goldstone boson dark matter at loop levelOct 18 2018Dec 11 2018In the standard model extended by a single complex scalar boson with a softly broken global U(1) symmetry, a pseudo Nambu-Goldstone boson becomes a candidate for dark matter. In this paper, we discuss the direct detection of the pseudo Nambu-Goldstone ... More
Implications of Two-component Dark Matter Induced by Forbidden Channels and Thermal Freeze-outNov 21 2016Jan 20 2017We consider a model of two-component dark matter based on a hidden $U(1)_D$ symmetry, in which relic densities of the dark matter are determined by forbidden channels and thermal freeze-out. The hidden $U(1)_D$ symmetry is spontaneously broken to a residual ... More
Impact of Semi-annihilation of Z3 Symmetric Dark Matter with Radiative Neutrino MassesMay 22 2014Sep 09 2014We investigate a Z3 symmetric model with two-loop radiative neutrino masses. Dark matter in the model is either a Dirac fermion or a complex scalar as a result of an unbroken Z3 symmetry. In addition to standard annihilation processes, semi-annihilation ... More
Reconciliation of CDM abundance and $μ\to eγ$ in a radiative seesaw modelMar 02 2009May 08 2009We reexamine relic abundance of a singlet fermion as a CDM candidate, which contributes to the neutrino mass generation through radiative seesaw mechanism. We search solutions for Yukawa couplings and the mass spectrum of relevant fields to explain neutrino ... More
Multicomponent dark matter particles in a two-loop neutrino modelMar 29 2013Jul 08 2013We construct a loop induced seesaw model in a TeV scale theory with gauged U(1)_{B-L} symmetry. Light neutrino masses are generated at two-loop level and right-handed neutrinos also obtain their masses by one-loop effect. Multi-component Dark Matters ... More
A Radiative Neutrino Mass Model with SIMP Dark MatterMay 01 2017Jul 27 2017We propose the first viable radiative seesaw model, in which the neutrino masses are induced radiatively via the two-loop Feynman diagram involving Strongly Interacting Massive Particles (SIMP). The stability of SIMP dark matter (DM) is ensured by a $\mathbb{Z}_5$ ... More
Non-thermal Production of Minimal Dark Matter via Right-handed Neutrino DecayJul 06 2015Sep 29 2015Minimal Dark Matter (MDM) stands as one of the simplest dark matter scenarios. In MDM models, annihilation and co-annihilation processes among the members of the MDM multiplet are usually very efficient, pushing the dark matter mass above $\mathcal{O}(10)$ ... More
Systematic U(1)_{B-L} Extensions of Loop-Induced Neutrino Mass Models with Dark MatterApr 27 2016We study the gauged U(1)_{B-L} extensions of the models for neutrino masses and dark matter. In this class of models, tiny neutrino masses are radiatively induced through the loop diagrams, while the origin of the dark matter stability is guaranteed by ... More
New Interpretation of the Recent Result of AMS-02 and Multi-component Decaying Dark Matters with non-Abelian Discrete Flavor SymmetryApr 09 2013Dec 23 2013Recently the AMS-02 experiment has released the data of positron fraction with much small statistical error. Because of the small error, it is no longer easy to fit the data with a single dark matter for a fixed diffusion model and dark matter profile. ... More
Direct and Indirect Detection of Dark Matter in D6 Flavor Symmetric ModelApr 03 2011Jun 12 2011We study a fermionic dark matter in a non-supersymmetric extension of the standard model with a family symmetry based on D6xZ2xZ2. In our model, the final state of the dark matter annihilation is determined to be e+ e- by the flavor symmetry, which is ... More
A new mechanism of sterile neutrino dark matter productionFeb 08 2018We consider a scenario where the dark matter candidate is a sterile neutrino with sizable self-interactions, described by a dimension-six operator, and with negligible interactions with the Standard Model. The relic abundance is set by the freeze-out ... More
A $μ$-$τ$-philic scalar doublet under $Z_n$ flavor symmetryApr 24 2019We propose a minimal model which accommodate the long-standing anomaly of muon magnetic moment based on abelian discrete flavor symmetries. The standard model is extended by scalar doublets charged under a $Z_n$ lepton flavor symmetry. In these models, ... More
A light Scalar Dark Matter for CoGeNT and DAMA in D_6 Flavor Symmetric ModelSep 13 2011We try to interpret a very light dark matter with mass of 5~10 GeV which is in favor of the recent experiments reported by CoGeNT and DAMA, in a non-supersymmetric extension of radiative seesaw model with a family symmetry D_6 x Z_2 x Z_2. We show that ... More
Nonthermal dark matter models and signalsNov 03 2015Mar 04 2016Many experiments exploring weakly interacting massive particles (WIMPs) such as direct, indirect and collider searches have been carried out until now. However, a clear signal of a WIMP has not been found yet and it makes us to suspect that WIMPs are ... More
Probing the Efficiency of Electron-Proton Coupling in Relativistic Collisionless Shocks through the Radio Polarimetry of Gamma-Ray Burst AfterglowsSep 21 2007Dec 18 2007The late-time optical/radio afterglows of $\gamma$-ray bursts (GRBs) are believed to be synchrotron emission of electrons accelerated in relativistic collisionless shocks propagating in the ambient medium of the sources. However, the fraction $f$ of electrons ... More
Ep-Eiso Correlation in a Multiple Subjet Model of Gamma-Ray BurstsApr 28 2005Aug 22 2005We perform Monte Carlo simulations to study Ep-Eiso correlation in the context of a multiple subjet model (or inhomogeneous jet model) for gamma-ray bursts (GRBs), X-ray--rich GRBs (XRRs), and X-ray flashes (XRFs). For a single subjet, we find that Ep ... More
Right-handed Sneutrino Dark Matter in Supersymmetric B-L ModelFeb 21 2011Jun 22 2011We show that the lightest right-handed sneutrino in TeV scale supersymmetric B-L model with inverse seesaw mechanism is a viable candidate for cold dark matter. We find that it accounts for the observed dark matter relic abundance in a wide range of parameter ... More
Neutrino masses and $μ$ terms in a supersymmetric extra U(1) modelOct 16 2009Aug 30 2010We propose a supersymmetric extra U(1) model, which can generate small neutrino masses and necessary $\mu$ terms, simultaneously. Fields including quarks and leptons are embedded in three ${\bf 27}$s of $E_6$ in a different way among generations. The ... More
Two Component Dark Matters in S_4 x Z_2 Flavor Symmetric Extra U(1) ModelJun 23 2011Sep 30 2011We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra U(1) model with S_4 x Z_2 flavor symmetry. In our model, the lightest flavon has very long lifetime of O(10^{18)) second which is longer than the age of the universe, but not long ... More
Light Dark Matter Candidate in B-L Gauged Radiative Inverse SeesawOct 08 2012Mar 19 2013We study a radiative inverse seesaw model with local B-L symmetry, in which we extend the neutrino mass structure that is generated through a kind of inverse seesaw framework to the more generic one than our previous work. We focus on a real part of bosonic ... More
Two Loop Neutrino Model and Dark Matter Particles with Global $B-L$ SymmetryDec 13 2013May 25 2014We study a two loop induced seesaw model with global $U(1)_{B-L}$ symmetry, in which we consider two component dark matter particles. The dark matter properties are investigated together with some phenomenological constraints such as electroweak precision ... More
Neutrino masses from Planck-scale lepton number breakingFeb 27 2018We consider an extension of the Standard Model by right-handed neutrinos and we argue that, under plausible assumptions, a neutrino mass of ${\cal O}(0.1)\,{\rm eV}$ is naturally generated by the breaking of the lepton number at the Planck scale, possibly ... More
A Possible Origin of Bimodal Distribution of Gamma-Ray BurstsJul 01 2004Jan 16 2005We study the distribution of the durations of gamma-ray bursts (GRBs) in the unified model of short and long GRBs recently proposed by Yamazaki, Ioka, and Nakamura. Monte Carlo simulations show clear bimodal distributions, with lognormal-like shapes for ... More
Signals of dark matter in a supersymmetric two dark matter modelDec 17 2010Jun 16 2011Supersymmetric radiative neutrino mass models have often two dark matter candidates. One is the usual lightest neutralino with odd R parity and the other is a new neutral particle whose stability is guaranteed by a discrete symmetry that forbids tree-level ... More
Neutrino masses from Planck-scale lepton number breakingFeb 27 2018Feb 22 2019We consider an extension of the Standard Model by right-handed neutrinos and we argue that, under plausible assumptions, a neutrino mass of ${\cal O}(0.1)\,{\rm eV}$ is naturally generated by the breaking of the lepton number at the Planck scale, possibly ... More
Enhancement of the annihilation of dark matter in a radiative seesaw modelFeb 17 2010Jul 27 2010The radiative seesaw model with an inert doublet has been shown to be attractive from a viewpoint of both neutrino masses and cold dark matter. However, if we apply this model to the explanation of the positron excess in the cosmic ray observed by PAMELA, ... More
Inert Extension of the Zee-Babu ModelAug 05 2014We propose a two-loop induced Zee-Babu type neutrino mass model at the TeV scale. Although there is no dark matter candidate in the original Zee-Babu model, that is contained in our model by introducing an unbroken discrete $Z_2$ symmetry. The discrepancy ... More
Seesaw Mechanism Confronting PAMELA in S_4 Flavor Symmetric Extra U(1) ModelOct 24 2010We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra U(1) model with S_4 flavor symmetry. In our model, the lightest flavon has very long lifetime of O(10^18) second which is longer than the age of the universe, but not long enough ... More
Systematic U(1)_{B-L} Extensions of Loop-Induced Neutrino Mass Models with Dark MatterApr 27 2016Oct 19 2016We study the gauged U(1)_{B-L} extensions of the models for neutrino masses and dark matter. In this class of models, tiny neutrino masses are radiatively induced through the loop diagrams, while the origin of the dark matter stability is guaranteed by ... More
Direct Detection of Leptophilic Dark Matter in a Model with Radiative Neutrino MassesJan 04 2012Mar 17 2012We consider an electro-weak scale model for Dark Matter (DM) and radiative neutrino mass generation. Despite the leptophilic nature of DM with no direct couplings to quarks and gluons, scattering with nuclei is induced at the 1-loop level through photon ... More
Absolutely continuous invariant measures for some piecewise hyperbolic affine mapsOct 31 2005A class of piecewise affine hyperbolic maps on a bounded subset of the plane is considered. It is shown that if a map from this class is sufficiently area-expanding then almost surely this map has an absolutely continuous invariant measure.
Latent Tree Language ModelJul 24 2016Sep 05 2016In this paper we introduce Latent Tree Language Model (LTLM), a novel approach to language modeling that encodes syntax and semantics of a given sentence as a tree of word roles. The learning phase iteratively updates the trees by moving nodes according ... More
The Pedestrian's Guide to Local TimeDec 30 2015These notes contains an introduction to the theory of Brownian and diffusion local time, as well as its relations to the Tanaka Formula, the extended Ito-Tanaka formula for convex functions, the running maximum process, and the theory of regulated stochastic ... More
Supersymmetric solutions of 4-dimensional supergravitiesOct 07 2010We review some general and recent results on the characterization and construction of timelike supersymmetric solutions of 4-dimensional supergravity theories.
Agujeros negros clasicos y cuanticos en teoria de cuerdasApr 30 2004Introductory lectures on classical and quantum string black holes (supergravity, branes and dualities) given at the VII School "La Hechicera" of Relativity, Fields and Astrophysics, held in the University of Los Andes, Merida (Venezuela) 2001. Fully in ... More
A unified approach to determining the early exercise boundary position at expiry for American style of general class of derivativesDec 01 2010Mar 24 2011In this paper, we present a new method for calculating the limit of early exercise boundary at expiry. We price American style of general derivative using a formula expressed as a sum of the value of European style of derivative and so called American ... More
Numerical solution for the anisotropic Willmore flow of graphsNov 13 2011The Willmore flow is well known problem from the differential geometry. It minimizes the Willmore functional defined as integral of the mean-curvature square over given manifold. For the graph formulation, we derive modification of the Willmore flow with ... More
Prony's method in several variables: symbolic solutions by universal interpolationMar 12 2016The paper considers a symbolic approach to Prony's method in several variables and its close connection to multivariate polynomial interpolation. Based on the concept of universal interpolation that can be seen as a weak generalization of univariate Chebychev ... More
Single-cell atomic quantum memory for lightSep 14 2005Sep 29 2006Recent experiments demonstrating atomic quantum memory for light [B. Julsgaard et al., Nature 432, 482 (2004)] involve two macroscopic samples of atoms, each with opposite spin polarization. It is shown here that a single atomic cell is enough for the ... More
Twenty-Five Moves Suffice for Rubik's CubeMar 24 2008How many moves does it take to solve Rubik's Cube? Positions are known that require 20 moves, and it has already been shown that there are no positions that require 27 or more moves; this is a surprisingly large gap. This paper describes a program that ... More
Spontaneous symmetry breaking in the linear sigma model at finite chemical potential: One-loop correctionsJul 10 2006Sep 22 2006We investigate spontaneous symmetry breaking within the linear sigma model with the SU(2)xU(1) internal symmetry at finite chemical potential, which was suggested as a model for kaon condensation in the CFL phase of dense quark matter. One-loop corrections ... More
A new approach to Sobolev spaces in metric measure spacesApr 29 2015Apr 19 2016Let $(X,d_X,\mu)$ be a metric measure space where $X$ is locally compact and separable and $\mu$ is a Borel regular measure such that $0 <\mu(B(x,r)) <\infty$ for every ball $B(x,r)$ with center $x \in X$ and radius $r>0$. We define $\mathcal{X}$ to be ... More
Hankel and Toeplitz operators of finite rank and Prony's problem in several variablesMay 22 2018Prony's problem in several variables has attracted some attention recently and provides an interesting combination of polynomial ideal theory with analytic and numeric computations. This note points out further connections to Hankel operators of finite ... More
A Unified Model for Gamma-Ray BurstsFeb 23 2005A possible unified model of short and long gamma-ray bursts (GRBs), X-ray rich GRBs, and X-ray flashes is proposed. It is assumed that the jet of a GRB consists of many emitting sub-shells (i.e., an inhomogeneous jet model). The multiplicity of the sub-shells ... More
A Unified Model of Short and Long Gamma-Ray Bursts, X-Ray Rich Gamma-Ray Bursts, and X-Ray FlashesOct 29 2004We propose a possible unified model of short and long gamma-ray bursts (GRBs), X-ray rich GRBs, and X-ray flashes. The jet of a GRB is assumed to consist of multiple sub-jets or sub-shells (i.e., an inhomogeneous jet model). The multiplicity of the sub-jets ... More
Sharp Gamma-ray Spectral Features from Scalar Dark Matter AnnihilationsMay 27 2014The search for sharp features in the gamma-ray spectrum is a promising approach to identify a signal from dark matter annihilations over the astrophysical backgrounds. In this paper we investigate the generation of gamma-ray lines and internal bremsstrahlung ... More
Efficiency Crisis of Swift Gamma-Ray Bursts with Shallow X-ray Afterglows: Prior Activity or Time-Dependent Microphysics?Nov 27 2005Jul 27 2006Most X-ray afterglows of gamma-ray bursts (GRBs) observed by the Swift satellite have a shallow decay phase t^{-1/2} in the first few hours. This is not predicted by the standard afterglow model and needs an explanation. We discuss that the shallow decay ... More
Tail Emission of Prompt Gamma-Ray Burst JetsSep 07 2005Apr 04 2006Tail emission of the prompt gamma-ray burst (GRB) is discussed using a multiple emitting sub-shell (inhomogeneous jet, sub-jets or mini-jets) model, where the whole GRB jet consists of many emitting sub-shells. One may expect that such a jet with angular ... More
Shallow Decay of Early X-ray Afterglows from Inhomogeneous Gamma-Ray Burst JetsNov 25 2005Feb 16 2006Almost all the X-ray afterglows of gamma-ray bursts (GRBs) observed by the Swift satellite have a shallow decay phase in the first thousands of seconds. We show that in an inhomogeneous jet (multiple-subjet or patchy-shell) model the superposition of ... More
Evading Direct Dark Matter Detection in Higgs Portal ModelsNov 29 2016Many models of Higgs portal Dark Matter (DM) find themselves under pressure from increasingly tight direct detection constraints. In the framework of gauge field DM, we study how such bounds can be relaxed while retaining the thermal WIMP paradigm. When ... More
Two Loop Neutrino Model with Dark Matter and LeptogenesisMay 18 2015Jul 08 2016We study a two-loop induced radiative neutrino model at TeV scale with global $U(1)$ symmetry, in which we analyze dark matter and resonant leptogenesis. The model includes two kinds of dark matter candidates. We discuss what kind of dark matter can satisfy ... More
Low-Luminosity GRB 060218: A Collapsar Jet from a Neutron Star, Leaving a Magnetar as a Remnant?Oct 30 2006Jan 08 2007The gamma-ray burst (GRB) 060218 has ~ 10^5 times lower luminosity than typical long GRBs, and is associated with a supernova (SN). The radio afterglow displays no jet break, so that this burst might arise from a mildly-relativistic spherical outflow ... More
Unstable GRB photospheres and electron-positron annihilation linesAug 09 2007We propose an emission mechanism of prompt gamma-ray bursts (GRBs) that can reproduce the observed non-thermal spectra with high radiative efficiencies, >50%. Internal dissipation below a photosphere can create a radiation-dominated thermal fireball. ... More
A nonparametric graphical tests of significance in functional GLMFeb 13 2019A new nonparametric graphical test of significance of a covariate in functional GLM is proposed. Our approach is especially interesting due to its functional graphical interpretation of the results. As such it is able to find not only if the factor of ... More
Water Observed in Red Giant and Supergiant Stars - Manifestation of a Novel Picture of the Stellar Atmosphere or else Evidence against the Classical Model Stellar PhotosphereSep 24 2002We detected the H2O 6.3 micron bands in more than 30 normal red giants stars from K5III to M8III as well as in some early M supergiants on the SWS spectra retrieved from the ISO Data Archive. This result, however, shows serious inconsistency with the ... More
Dust in the Photospheric Environment: Unified Cloudy Models of M, L, and T DwarfsApr 24 2002May 02 2002We address the problem of how dust forms and how it could be sustained in the static photospheres of cool dwarfs for a long time. In the cool and dense gas, dust forms easily at the condensation temperature, T_cond, and the dust can be in detailed balance ... More
A Bratteli--Vershik representation for all zero-dimensional systemsMar 12 2016We show that every zero-dimensional system can have Bratteli--Vershik representation. As a corollary, we get an analogue of the Krieger's Lemma for zero-dimensional systems.
High-energy effects on the spectrum of inflationary gravitational wave background in braneworld cosmologyJan 16 2006Apr 14 2006We discuss the cosmological evolution of the inflationary gravitational wave background (IGWB) in the Randall-Sundrum single-brane model. In the braneworld cosmology, in which three-dimensional space-like hypersurface that we live in is embedded in five-dimensional ... More
Cosmological pseudobulge formationJun 24 2012Bulges can be classified into classical and pseudobulges; the former are considered to be end products of galactic mergers and the latter to form via secular evolution of galactic disks. Observationally, bulges of disk galaxies are mostly pseudobulges, ... More
Power-law exponent of the Bouchaud-Mézard model on regular random networkJul 18 2013We study the Bouchaud-M\'ezard model on a regular random network. By assuming adiabaticity and independency, and utilizing the generalized central limit theorem and the Tauberian theorem, we derive an equation that determines the exponent of the probability ... More
Quasi-equilibrium nonadditivityApr 30 2014The possibility that a short-range interacting system exhibits nonadditivity is investigated. After the discussion on the precise definition of additivity and its consequence, we show that it is possible when the system is in a quasi-equilibrium state ... More
Exactness of the mean-field dynamics in optical cavity systemsDec 30 2012Jun 20 2013Validity of the mean-field approach to open system dynamics in the optical cavity system is examined. It is rigorously shown that the mean-field approach is justified in the thermodynamic limit. The result is applicable to nonequilibrium situations, e.g. ... More
Microcanonical Analysis of Exactness of the Mean-Field Theory in Long-Range Interacting SystemsNov 04 2011May 23 2012Classical spin systems with nonadditive long-range interactions are studied in the microcanonical ensemble. It is expected that the entropy of such a system is identical to that of the corresponding mean-field model, which is called "exactness of the ... More
Extensive increase of entropy in quantum quenchJun 23 2016Oct 25 2016In the setup of isolated quantum systems, it is proved that the thermodynamic entropy and the diagonal entropy must increase extensively in any nontrivial quantum quench. The extensive increase of the thermodynamic entropy is shown for any initial state ... More
Almost collapse mass quantization in 2D Smoluchowski-Poisson equationNov 22 2013We study Smoluchowski-Poisson equation in two space dimensions provided with Dirichlet boundary condition for the Poisson part. For this equation several profiles of blowup solution have been noticed. Here we show collapse mass quantization with possible ... More
More on $U_q(su(1,1))$ with $q$ a Root of UnityDec 10 1993Highest weight representations of $U_q(su(1,1))$ with $q=\exp \pi i/N$ are investigated. The structures of the irreducible hieghesat weight modules are discussed in detail. The Clebsch-Gordan decomposition for the tensor product of two irreducible representations ... More
A pentaquark picture of Lambda(1405)Aug 17 2007We test a pentaquark model of the negative parity hyperon Lambda(1405). We use a model where valence four quarks and one antiquark move in a potential relativistically and interact with each other and themselves through gluon and NG boson. Fall-apart ... More
Long wavelength limit of evolution of cosmological perturbations in the universe where scalar fields and fluids coexistNov 19 2007We present the LWL formula which represents the long wavelengh limit of the solutions of evolution equations of cosmological perturbations in terms of the exactly homogeneous solutions in the most general case where multiple scalar fields and multiple ... More
A mean value theorem for orders of degree zero divisor class groups of quadratic extensions over a function fieldMar 14 2002Let $k$ be a function field of one variable over a finite field with the characteristic not equal to two. In this paper, we consider the prehomogeneous representation of the space of binary quadratic forms over $k$. We have two main results. The first ... More
Real zeros of Hurwitz-Lerch zeta functions in the interval $(-1,0)$Dec 01 2015For $0 < a \le 1$, $s,z \in {\mathbb{C}}$ and $0 < |z|\le 1$, the Hurwitz-Lerch zeta function is defined by $\Phi (s,a,z) := \sum_{n=0}^\infty z^n(n+a)^{-s}$ when $\sigma :=\Re (s) >1$. In this paper, we show that $\Phi (\sigma,a,z) \ne 0$ when $\sigma ... More
Equations associated to the Principal Congruence Subgroup of Level EightMar 22 2016The purpose of this paper is to find an equation with respect to the principal congruence subgroup of level eight without considering modular functions.
Decay of correlations in nearest-neighbor self-avoiding walk, percolation, lattice trees and animalsApr 06 2005Apr 21 2008We consider nearest-neighbor self-avoiding walk, bond percolation, lattice trees, and bond lattice animals on ${\mathbb{Z}}^d$. The two-point functions of these models are respectively the generating function for self-avoiding walks from the origin to ... More
Notes on mixed Teichmüller motivesDec 26 2016Nov 13 2017As a higher genus version of universal mixed elliptic motives by Hain and Matsumoto, we consider mixed Teichm\"uller motives as certain motivic local systems on the moduli space of pointed curves. We show that the category of mixed Teichm\"uller motives ... More
Convergence of the Allen-Cahn equation with a zero Neumann boundary condition on non-convex domainsOct 02 2017Apr 06 2018We study a singular limit problem of the Allen-Cahn equation with the homogeneous Neumann boundary condition on non-convex domains with smooth boundaries under suitable assumptions for initial data. The main result is the convergence of the time parametrized ... More
A twisted moment map and its equivarianceFeb 08 2011Mar 19 2013Let $G$ be a linear connected complex reductive Lie group. The purpose of this paper is to give explicit symplectic isomorphisms from twisted cotangent bundles of the complex generalized flag varieties, whose transition functions are given by affine transformations ... More
An improvement of the duality formalism of the rational etale siteFeb 10 2019We improve the arithmetic duality formalism of the rational etale site. This improvement allows us to avoid some exotic approximation arguments on local fields with ind-rational base, thus simplifying the proofs of the previously established duality theorems ... More
Neron models of 1-motives and dualityJun 20 2018Mar 22 2019In this paper, we propose a definition of Neron models of arbitrary Deligne 1-motives over Dedekind schemes, extending Neron models of semi-abelian varieties. The key property of our Neron models is that they satisfy a generalization of Grothendieck's ... More
Construction of scrambled polynomial lattice rules over $\mathbb{F}_2$ with small mean square weighted $\mathcal{L}_2$ discrepancyJan 17 2013Jun 20 2014The $\mathcal{L}_2$ discrepancy is one of several well-known quantitative measures for the equidistribution properties of point sets in the high-dimensional unit cube. The concept of weights was introduced by Sloan and Wo\'{z}niakowski to take into account ... More
Computing the variance of a conditional expectation via non-nested Monte CarloMay 18 2016Sep 27 2016Computing the variance of a conditional expectation has often been of importance in uncertainty quantification. Sun et al. has introduced an unbiased nested Monte Carlo estimator, which they call $1\frac{1}{2}$-level simulation since the optimal inner-level ... More
Quantum Real Lines,Infinitesimal Structure of $\R$May 22 2002We present in this paper quantum real lines as quantum defomations of the real numbers $\R$.Upon deforming the Heisenberg algebra $\cL$ generated by $(a, a^\dagger)$ in terms of the Moyal $\ast$-product,we first construct q-deformed algebras of q-differentiable ... More
A Note on Quantum Liouville Theory via Quantum Group; an Approach to Strong Coupling Liouville TheoryNov 22 1996Quantum Liouville theory is analyzed in terms of the infinite dimensional representations of $U_Qsl(2,C)$ with q a root of unity. Making full use of characteristic features of the representations, we show that vertex operators in this Liouville theory ... More
Towards a Strong Coupling Liouville GravityOct 13 1994A possibility of strong coupling quantum Liouville gravity is investigated via infinite dimensional representations of $\qslc$ with $q$ at a root of unity. It is explicitly shown that vertex operator in this model can be written by a tensor product of ... More
Renormalization group analysis of the hyperbolic sine-Gordon model -- Asymptotic freedom from cosh interaction --Feb 20 2019We present a renormalization group analysis for the hyperbolic sine-Gordon (sinh-Gordon) model in two dimensions. We derive the renormalization group equations based on the dimensional regularization method and the Wilson method. The same equations are ... More
Whitney umbrellas and swallowtailsDec 21 2011In this paper, we introduce the notions of map-germs of pedal unfolding type and normalized Legendrian map-germs; and then we show that the fundamental theorem of calculus provides a natural one to one correspondence between Whitney umbrellas of pedal ... More