Results for "Ken D. Olum"

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Scaling of cosmic string loopsNov 29 2005Jun 20 2006We study the spectrum of loops as a part of a complete network of cosmic strings in flat spacetime. After a long transient regime, characterized by production of small loops at the scale of the initial conditions, it appears that a true scaling regime ... More
Universal Doomsday: Analyzing Our Prospects for SurvivalMar 19 2013Given a sufficiently large universe, numerous civilizations almost surely exist. Some of these civilizations will be short-lived and die out relatively early in their development, i.e., before having the chance to spread to other planets. Others will ... More
Philosophical Implications of Inflationary CosmologyFeb 20 2003Oct 26 2005Recent developments in cosmology indicate that every history having a nonzero probability is realized in infinitely many distinct regions of spacetime. Thus, it appears that the universe contains infinitely many civilizations exactly like our own, as ... More
Cosmic string formation by flux trappingJun 11 2007Aug 01 2007We study the formation of cosmic strings by confining a stochastic magnetic field into flux tubes in a numerical simulation. We use overdamped evolution in a potential that is minimized when the flux through each face in the simulation lattice is a multiple ... More
Quantum tunneling of superconducting string currentsFeb 13 2002We investigate the decay of current on a superconducting cosmic string through quantum tunneling. We construct the instanton describing tunneling in a simple bosonic string model, and estimate the decay rate. The tunneling rate vanishes in the limit of ... More
Dynamics of superconducting strings with chiral currentsApr 28 2000Mar 07 2001We rederive, using an elementary formalism, the general solution to the equations of motion for a superconducting string with a chiral (null) neutral current, earlier obtained by Carter and Peter. We apply this solution to show that the motion of such ... More
Gravitational backreaction simulations of simple cosmic string loopsMar 14 2019We present the results of computational gravitational backreaction on simple models of cosmic string loops. These results give us insight into the general behavior of cusps and kinks on loops, in addition to other features of evolution. Kinks are rounded ... More
Entropy of Localized States and Black Hole EvaporationOct 11 1996Nov 20 1996We call a state "vacuum-bounded" if every measurement performed outside a specified interior region gives the same result as in the vacuum. We compute the maximum entropy of a vacuum-bounded state with a given energy for a one-dimensional model, with ... More
The Ori-Soen time machineJul 02 1999Apr 18 2000Ori and Soen have proposed a spacetime which has closed causal curves on the boundary of a region of normal causality, all within a region where the weak energy condition (positive energy density) is satisfied. I analyze the causal structure of this spacetime ... More
Negative Energy Densities in Quantum Field Theory With a Background PotentialNov 25 2002Dec 30 2003We present a general procedure for calculating one-loop ``Casimir'' energy densities for a scalar field coupled to a fixed potential in renormalized quantum field theory. We implement direct subtraction of counterterms computed precisely in dimensional ... More
Auxiliary variables for nonlinear equations with softly broken symmetriesNov 12 2016General methods of solving equations deal with solving N equations in N variables and the solutions are usually a set of discrete values. However, for problems with a softly broken symmetry these methods often first find a point which would be a solution ... More
Are there Boltzmann brains in the vacuumAug 04 2010"Boltzmann brains" are human brains that arise as thermal or quantum fluctuations and last at least long enough to think a few thoughts. In many scenarios involving universes of infinite size or duration, Boltzmann brains are infinitely more common than ... More
Achronal averaged null energy conditionMay 22 2007Aug 27 2007The averaged null energy condition (ANEC) requires that the integral over a complete null geodesic of the stress-energy tensor projected onto the geodesic tangent vector is never negative. This condition is sufficient to prove many important theorems ... More
Static Negative Energies Near a Domain WallMay 31 2002Dec 07 2002We show that a system of a domain wall coupled to a scalar field has static negative energy density at certain distances from the domain wall. This system provides a simple, explicit example of violation of the averaged weak energy condition and the quantum ... More
Plate with a hole obeys the averaged null energy conditionJun 16 2005Nov 07 2005The negative energy density of Casimir systems appears to violate general relativity energy conditions. However, one cannot test the averaged null energy condition (ANEC) using standard calculations for perfectly reflecting plates, because the null geodesic ... More
Can a circulating light beam produce a time machine?Oct 17 2004In a recent paper, Mallett found a solution of the Einstein equations in which closed timelike curves (CTC's) are present in the empty space outside an infinitely long cylinder of light moving in circular paths around an axis. Here we show that, for physically ... More
Reionization from cosmic string loopsMay 18 2006Loops formed from a cosmic string network at early times would act as seeds for early formation of halos, which would form galaxies and lead to early reionization. With reasonable guesses about astrophysical and string parameters, the cosmic string scale ... More
Efficient numerical solution to vacuum decay with many fieldsOct 20 2016Nov 02 2016Finding numerical solutions describing bubble nucleation is notoriously difficult in more than one field space dimension. Traditional shooting methods fail because of the extreme non-linearity of field evolution over a macroscopic distance as a function ... More
Dynamics of Cosmic NecklacesMay 19 2000We perform numerical simulations of cosmic necklaces (systems of monopoles connected to two strings each) and investigate the conditions under which monopoles annihilate. When the total monopole energy is large compared to the string energy, we find that ... More
Gravitational smoothing of kinks on cosmic string loopsSep 01 2016Sep 08 2016We analyze the effect of gravitational back reaction on cosmic string loops with kinks, which is an important determinant of the shape, and thus the potential observability, of string loops which may exist in the universe today. Kinks are not rounded ... More
On the size of the smallest scales in cosmic string networksMar 02 2002We present a method for the calculation of the gravitational back reaction cutoff on the smallest scales of cosmic string networks taking into account that not all modes on strings interact with all other modes. This results in a small scale structure ... More
Anomalous Observers in the Subjectively Identical Reference ClassApr 09 2013Anthropic reasoning is a critical tool to understand probabilities, especially in a large universe or multiverse. According to anthropic reasoning, we should consider ourselves typical among members of a reference class that must include all subjectively ... More
Efficient numerical solution to vacuum decay with many fieldsOct 20 2016Finding numerical solutions describing bubble nucleation is notoriously difficult in more than one field space dimension. Traditional shooting methods fail because of the extreme non-linearity of field evolution over a macroscopic distance as a function ... More
Electromagnetic back-reaction from currents on a straight stringMay 08 2014Jul 07 2014Charge carriers moving at the speed of light along a straight, superconducting cosmic string carry with them a logarithmically divergent slab of electromagnetic field energy. Thus no finite local input can induce a current that travels unimpeded to infinity. ... More
Gravitational back reaction on piecewise linear cosmic string loopsSep 06 2016We calculate the metric and affine connection due to a piecewise linear cosmic string loop, and the effect of gravitational back reaction for the Garfinkle-Vachaspati loop with four straight segments. As expected, back reaction reduces the size of the ... More
Detectability of gravitational effects of supernova neutrino emission through pulsar timingMay 16 2013May 17 2013Core-collapse supernovae emit on the order of 3x10^53 ergs in high-energy neutrinos over a time of order 10 seconds, and so decrease their mass by about 0.2 solar mass. If the explosion is nearly spherically symmetric, there will be little gravitational ... More
Cosmic string loop shapesAug 11 2015We analyze the shapes of cosmic string loops found in large-scale simulations of an expanding-universe string network. The simulation does not include gravitational back reaction, but we model that process by smoothing the loop using Lorentzian convolution. ... More
Gravitational back-reaction near cosmic string kinks and cuspsAug 24 2018Aug 31 2018We find the leading-order effect of gravitational back-reaction on cosmic strings for points near kinks and cusps. Near a kink, the effect diverges as the inverse cube root of the distance to the kink, and acts in a direction transverse to the worldsheet. ... More
Energy conditions outside a dielectric ballJul 01 2004We show analytically that the vacuum electromagnetic stress-energy tensor outside a ball with constant dielectric constant and permeability always obeys the weak, null, dominant, and strong energy conditions. There are still no known examples in quantum ... More
Averaged null energy condition in spacetimes with boundariesSep 01 2006Sep 10 2007The Averaged Null Energy Condition (ANEC) requires that the average along a complete null geodesic of the projection of the stress-energy tensor onto the geodesic tangent vector can never be negative. It is sufficient to rule out many exotic phenomena ... More
UHE neutrinos from superconducting cosmic stringsJan 05 2009Nov 04 2010Superconducting cosmic strings naturally emit highly boosted charge carriers from cusps. This occurs when a cosmic string or a loop moves through a magnetic field and develops an electric current. The charge carriers and the products of their decay, including ... More
Energy-Momentum Restrictions on the Creation of Gott Time MachinesMay 01 1994The discovery by Gott of a remarkably simple spacetime with closed timelike curves (CTC's) provides a tool for investigating how the creation of time machines is prevented in classical general relativity. The Gott spacetime contains two infinitely long, ... More
Reduction of CM elliptic curves and modular function congruencesDec 15 2005We study congruences of the form F(j(z)) | U(p) = G(j(z)) mod p, where U(p) is the p-th Hecke operator, j is the basic modular invariant 1/q+744+196884q+... for SL2(Z), and F,G are polynomials with integer coefficients. Using the interplay between singular ... More
Cosmic string scaling in flat spaceJan 12 2005Aug 16 2005We investigate the evolution of infinite strings as a part of a complete cosmic string network in flat space. We perform a simulation of the network which uses functional forms for the string position and thus is exact to the limits of computer arithmetic. ... More
Tunable structures of mixtures of magnetic particles in liquid-crystalline matricesApr 16 2015We investigate the self-organization of a binary mixture of similar sized rods and dipolar soft spheres by means of Monte-Carlo simulations. We model the interparticle interactions by employing anisotropic Gay-Berne, dipolar and soft-sphere interactions. ... More
Smooth distributions are finitely generatedDec 27 2010A subbundle of variable dimension inside the tangent bundle of a smooth manifold is called a smooth distribution if it is the pointwise span of a family of smooth vector fields. We prove that all such distributions are finitely generated, meaning that ... More
Detection of a 522 s Pulsation from the Transient X-ray Source Suzaku J0102.8--7204 (SXP 523) in the Small Magellanic CloudMar 01 2013During a routine calibration observation of 1E0102.2-7219 in the Small Magellanic Cloud (SMC) carried out in October 2012 for the Suzaku satellite, we detected a transient X-ray source at (RA, Dec) = (01h02m47s, -72d04m54s) in the equinox J2000.0 with ... More
A maximum entropy framework for non-exponential distributionsJan 06 2015Probability distributions having power-law tails are observed in a broad range of social, economic, and biological systems. We describe here a potentially useful common framework. We derive distribution functions $\{p_k\}$ for situations in which a `joiner ... More
The structure of automorphic loopsOct 05 2012Automorphic loops are loops in which all inner mappings are automorphisms. This variety of loops includes, for instance, groups and commutative Moufang loops. We study uniquely 2-divisible automorphic loops, particularly automorphic loops of odd order, ... More
Denotational Semantics of the Simplified Lambda-Mu Calculus and a New Deduction System of Classical Type TheoryJun 21 2016Classical (or Boolean) type theory is the type theory that allows the type inference $\sigma \to \bot) \to \bot => \sigma$ (the type counterpart of double-negation elimination), where $\sigma$ is any type and $\bot$ is absurdity type. This paper first ... More
Chaotic Monte Carlo computation: a dynamical effect of random-number generationsDec 10 1998Mar 02 1999It is shown that superefficient Monte Carlo computations can be carried out by using chaotic dynamical systems as non-uniform random-number generators. Here superefficiency means that the expectation value of the square of the error decreases to 0 as ... More
Singularity analysis towards nonintegrability of nonhomogeneous nonlinear latticesApr 16 1997We show non-integrability of the nonlinear lattice of Fermi-Pasta-Ulam type via the singularity analysis(Picard-Vessiot theory) of normal variational equations of Lam\'e type.
A Robust Approximation to a Lambert-Type FunctionApr 08 2015The function $y = g(x) = \mathrm{log}\big(W(e^x)\big)$, where $W()$ denotes the Lambert W function, is the solution to the equation $y + e^y = x$. It appears in various problem situations, for instance the calculation of current-voltage curves for solar ... More
Global well-posedness of the two-dimensional exterior Navier-Stokes equations for non-decaying dataAug 23 2016We prove global well-posedness of the two-dimensional exterior Navier-Stokes equations for bounded initial data with a finite Dirichlet integral, subject to the non-slip boundary condition. As an application, we construct global solutions for asymptotically ... More
Reality, No Matter How You Slice ItOct 30 2013In order to reject the notion that information is always about something, the "It from Bit" idea relies on the nonexistence of a realistic framework that might underly quantum theory. This essay develops the case that there is a plausible underlying reality: ... More
Establishing a direct connection between detrended fluctuation analysis and Fourier analysisAug 10 2015Nov 02 2015To understand methodological features of the detrended fluctuation analysis (DFA) using a higher-order polynomial fitting, we establish the direct connection between DFA and Fourier analysis. Based on an exact calculation of the single-frequency response ... More
Lazy Transformation-Based LearningJun 03 1998We introduce a significant improvement for a relatively new machine learning method called Transformation-Based Learning. By applying a Monte Carlo strategy to randomly sample from the space of rules, rather than exhaustively analyzing all possible rules, ... More
Real zeroes of random polynomials, II: Descartes' rule of signs and anti-concentration on the symmetric groupJan 19 2016In this sequel to Part-I, we present a different approach to bounding the expected number of real zeroes of random polynomials with real independent identically distributed coefficients or more generally, exchangeable coefficients. We show that the mean ... More
CFTs on curved spacesFeb 19 2019We study conformal field theories (CFTs) on curved spaces including both orientable and unorientable manifolds possibly with boundaries. We first review conformal transformations on curved manifolds. We then compute the identity components of conformal ... More
Tropical Theta Functions and Riemann-Roch Inequality for Tropical Abelian SurfacesSep 28 2018Jan 29 2019We show that the space of theta functions on tropical tori is identified with a convex polyhedron. We also show a Riemann-Roch inequality for tropical abelian surfaces by calculating the self-intersection numbers of divisors.
Canonical superdiffusion and energy fluctuation divergenceOct 05 2016We propose a noble physical model obtained from a Hamiltonian with periodic potential. This model is canonical, reversible and brings about chaotic superdiffusion with energy fluctuation divergence. The analytical formula of invariant density can be obtained ... More
Improvement of SNR with Chaotic Spreading Sequences for CDMAFeb 26 1999Mar 08 1999We show that chaotic spreading sequences generated by ergodic mappings of Chebyshev orthogonal polynomials have better correlation properties for CDMA(code division multiple access) than the optimal binary sequences (Gold sequences) in the sense of ensemble ... More
Quantum Theory without QuantizationJun 07 2011The only evidence we have for a discrete reality comes from quantum measurements; without invoking these measurements, quantum theory describes continuous entities. This seeming contradiction can be resolved via analysis that treats measurements as boundary ... More
The Universe is not a ComputerNov 29 2012Jan 27 2015When we want to predict the future, we compute it from what we know about the present. Specifically, we take a mathematical representation of observed reality, plug it into some dynamical equations, and then map the time-evolved result back to real-world ... More
Temperature Dependence of Extended and Fractional SU(3) Monopole CurrentsJan 11 1994Jun 15 1994We examine in pure SU(3) the dependence of extended monopole current k and cross-species extended monopole current k^{cross} on temperature t, monopole size L, and fractional monopole charge 1/q. We find that features of both k and k^{cross} are sensitive ... More
Central Charge of the Parallelogram Lattice Strong Coupling Schwinger ModelMay 27 1992We put forth a Fierzed hopping expansion for strong coupling Wilson fermions. As an application, we show that the strong coupling Schwinger model on parallelogram lattices with nonbacktracking Wilson fermions span, as a function of the lattice skewness ... More
Dirac Strings and the Nonperturbative Photon Propagator in Compact QEDDec 02 1992Dec 03 1992A ``3D'' Mathematica@-generated picture of monopoles and Dirac strings in $D=2+1$ compact QED is given. In the Villain approximation, the monopole part of the partition function factorizes from the Dirac string part, which generates the photon propagator. ... More
Lonesum decomposable matricesJan 25 2017A lonesum matrix is a $(0,1)$-matrix that is uniquely determined by its row and column sum vectors. In this paper, we introduce lonesum decomposable matrices and study their properties. We provide a necessary and sufficient condition for a matrix $A$ ... More
An HI census of Loose Groups of GalaxiesOct 03 2003We present results from our Parkes Multibeam HI survey of 3 loose groups of galaxies that are analogous to the Local Group. This is a survey of groups containing only spiral galaxies with mean separations of a few hundred kpc, and total areas of approximately ... More
General scaling relations for locomotion in granular mediaApr 08 2016Mar 18 2017We derive a general dimensionless form for granular locomotion, which is validated in experiments and Discrete Element Method (DEM) simulations. The form instructs how to scale size, mass, and driving parameters in order to relate dynamic behaviors of ... More
2.5D Deep Learning for CT Image Reconstruction using a Multi-GPU implementationDec 20 2018While Model Based Iterative Reconstruction (MBIR) of CT scans has been shown to have better image quality than Filtered Back Projection (FBP), its use has been limited by its high computational cost. More recently, deep convolutional neural networks (CNN) ... More
Learning to pinpoint effective operators at the LHC: a study of the $t\bar{t}b\bar{b}$ signatureOct 03 2018In the context of the Standard Model effective field theory (SMEFT), we study the LHC sensitivity to four fermion operators involving heavy quarks by employing cross section measurements in the $t\bar{t}b\bar{b}$ final state. Starting from the measurement ... More
Learning to pinpoint effective operators at the LHC: a study of the $t\bar{t}b\bar{b}$ signatureJul 05 2018Oct 17 2018In the context of the Standard Model effective field theory (SMEFT), we study the LHC sensitivity to four fermion operators involving heavy quarks by employing cross section measurements in the $t\bar{t}b\bar{b}$ final state. Starting from the measurement ... More
Canonical random variables for multivariate, algebra-valued distributionsDec 20 2015Jan 12 2016In the algebraic theory of algebra-valued noncommutative probability spaces, for a unital algebra B, a mild reformulation of Speicher's noncrossing B-valued cumulants for random variables in these spaces is used to construct canonical random variables, ... More
On estimates for the Stokes flow in a space of bounded functionsJun 20 2014Apr 21 2016In this paper, we study regularizing effects of the composition operator $S(t)\mathbb{P}\partial$ for the Stokes semigroup $S(t)$ and the Helmholtz projection $\mathbb{P}$ in a space of bounded functions. We establish new a priori $L^{\infty}$-estimates ... More
Real zeroes of random polynomials, I: Flip-invariance, Turán's lemma, and the Newton-Hadamard polygonJan 19 2016We show that with high probability the number of real zeroes of a random polynomial is bounded by the number of vertices on its Newton-Hadamard polygon times the cube of the logarithm of the polynomial degree. A similar estimate holds for zeroes lying ... More
Autonomous collision attack on OCSP servicesSep 10 2016The paper describes two important design flaws in Online Certificate Status Protocol (OCSP), a protocol widely used in PKI environments for managing digital certificates' credibility in real time. The flaws significantly reduce the security capabilities ... More
A Gaussian Mixture MRF for Model-Based Iterative Reconstruction with Applications to Low-Dose X-ray CTMay 12 2016Jun 13 2016Markov random fields (MRFs) have been widely used as prior models in various inverse problems such as tomographic reconstruction. While MRFs provide a simple and often effective way to model the spatial dependencies in images, they suffer from the fact ... More
Nuclear and Gamma-ray Production by Supernova EjectaJan 09 1996The fastest ejecta of supernova explosions propagate as a precursor to the main supernova shock wave, and can be quite energetic. The spectrum of such fast ejecta is estimated based on recent analytic and numerical supernova models, and found to be a ... More
Eternal inflation, black holes, and the future of civilizationsSep 08 1999May 16 2000We discuss the large-scale structure of the universe in inflationary cosmology and the implications that it may have for the long-term future of civilizations. Although each civilization is doomed to perish, it may be possible to transmit its accumulated ... More
A Search For Pulsations in the Optical Light Curve of the Nova ASASSN-17hxOct 16 2018Oct 18 2018We present high-speed optical observations of the nova ASASSN-17hx, taken both immediately after its discovery and close to its first peak in brightness, to search for seconds -- minutes pulsations associated with the convective eddy turnover timescale ... More
State Selection in Accelerated SystemsAug 27 1997The problem of state selection when multiple metastable states compete for occupation is considered for systems that are accelerated far from equilibrium. The dynamics of the supercurrent in a narrow superconducting ring under the influence of an external ... More
On the boundary behavior of the curvature of L2-metricsJul 16 2010For one-parameter degenerations of compact K\"ahler manifolds, we determine the asymptotic behavior of the first Chern form of the direct image of a Nakano semi-positive vector bundle twisted by the relative canonical bundle, when the direct image is ... More
K3 surfaces with involution, equivariant analytic torsion, and automorphic forms on the moduli space II: a structure theorem for r(M)>10Jul 16 2010We study the structure of the invariant of K3 surfaces with involution, which we obtained using equivariant analytic torsion. It was known before that the invariant is expressed as the Petersson norm of an automorphic form on the moduli space. When the ... More
On the singularity of Quillen metricsJan 18 2006We study the singularity of Quillen metrics for one-parameter degenerations of compact Kaehler manifolds.
Noetherian properties of rings of differential operators of affine semigroup algebrasJan 19 2007We consider the Noetherian properties of the ring of differential operators of an affine semigroup algebra. First we show that it is always right Noetherian. Next we give a condition, based on the data of the difference between the semigroup and its scored ... More
Stable presentation length of 3-manifold groupsJan 11 2015Jan 21 2018We introduce the stable presentation length of a finitely presented group. The stable presentation length of the fundamental group of a 3-manifold can be considered as an analogue of the simplicial volume. We show that the stable presentation length have ... More
Reduced Bers boundaries of Teichmüller spacesMar 24 2011Jun 16 2011We consider a quotient space of the Bers boundary of Teichm\"{u}ller space, which we call the reduced Bers boundary, by collapsing each quasi-conformal deformation space into a point. This reduced Bers boundary turns out to be independent of the basepoint, ... More
Quantum homogeneous spaces of connected Hopf algebrasJun 08 2015Let H be a connected Hopf k-algebra of finite Gel'fand-Kirillov dimension over an algebraically closed field k of characteristic 0. The objects of study in this paper are the left or right coideal subalgebras T of H. They are shown to be deformations ... More
TeV scale mirage mediation in NMSSM and precision Higgs measurementMar 14 2016We propose that the TeV scale mirage mediation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) is a novel solution for the little hierarchy problem in supersymmetry. The 125 GeV Higgs boson can be accommodated with the new quartic coupling ... More
Relic abundance and detection prospects of neutralino dark matter in mirage mediationOct 27 2006We analyze thermal relic abundance of neutralino dark matter and discuss future prospects of its direct and indirect detections in mirage mediation.
Computing Circumscriptive Databases by Integer Programming: Revisited (Extended Abstract)Mar 05 2000In this paper, we consider a method of computing minimal models in circumscription using integer programming in propositional logic and first-order logic with domain closure axioms and unique name axioms. This kind of treatment is very important since ... More
Correlation Analysis for Total Electron Content Anomalies on 11th March, 2011Jun 08 2016Jun 10 2016We can observe the changes of Total Electron Content, TEC, in ionosphere by analyzing the data from GNSS satellites. There are many reports about TEC anomalies after earthquakes, i.e. large earthquakes often disturb the ionosphere. Up to now, preseismic ... More
Dispelling the Quantum Spooks -- a Clue that Einstein Missed?Jul 29 2013It is well-known that Bell's Theorem and other No Hidden Variable theorems have a "retrocausal loophole", because they assume that the values of pre-existing hidden variables are independent of future measurement settings. (This is often referred to, ... More
Topology of crystalline insulators and superconductorsMar 13 2014Oct 14 2014We complete a classification of topological phases and their topological defects in crystalline insulators and superconductors. We consider topological phases and defects described by non-interacting Bloch and Bogoliubov de Gennes Hamiltonians that support ... More
Green's Function Method for Line Defects and Gapless Modes in Topological Insulators : Beyond Semiclassical ApproachNov 07 2011Jan 13 2012Defects which appear in heterostructure junctions involving topological insulators are sources of gapless modes governing the low energy properties of the systems, as recently elucidated by Teo and Kane [Physical Review B82, 115120 (2010)]. A standard ... More
Supersymmetric Wilson Loops in IIB Matrix ModelJun 26 1997Jul 03 1997We show that the supersymmetric Wilson loops in IIB matrix model give a transition operator from reduced supersymmetric Yang-Mills theory to supersymmetric space-time theory. In comparison with Green-Schwarz superstring we identify the supersymmetric ... More
Physical States, Factorization and Nonlinear Structures in Two Dimensional Quantum GravitySep 17 1993The nonlinear structures in 2D quantum gravity coupled to the $(q+1,q)$ minimal model are studied in the Liouville theory to clarify the factorization and the physical states. It is confirmed that the dressed primary states outside the minimal table are ... More
Dripping Faucet Dynamics Clarified by an Improved Mass-Spring ModelApr 06 1999An improved mass-spring model for a dripping faucet is presented. The model is constructed based on the numerical results which we recently obtained from fluid dynamical calculations. Both the fluid dynamical calculations and the present mass-spring model ... More
Intrusion in heterogeneous materials: Simple global rules from complex micro-mechanicsOct 10 2015The interaction of intruding objects with deformable materials is a common phenomenon, arising in impact and penetration problems, animal and vehicle locomotion, and various geo-space applications. The dynamics of arbitrary intruders can be simplified ... More
Fractal behind smart shoppingMar 07 2011The 'minimal' payment - a payment method which minimizes the number of coins in a purse - is presented. We focus on a time series of change given back to a shopper repeating the minimal payment. The delay plot shows visually that the set of successive ... More
Network of two-Chinese-character compound words in Japanese languageFeb 24 2009Some statistical properties of a network of two-Chinese-character compound words in Japanese language are reported. In this network, a node represents a Chinese character and an edge represents a two-Chinese-character compound word. It is found that this ... More
Structure and modeling of the network of two-Chinese-character compound words in the Japanese languageMay 09 2014This paper proposes a numerical model of the network of two-Chinese-character compound words (two-character network, for short). In this network, a Chinese character is a node and a two-Chinese-character compound word links two nodes. The basic framework ... More
A note on the rigidity of unmeasured lamination spacesDec 28 2011We show that every auto-homeomorphism of the unmeasured lamination space of an orientable surface of finite type is induced by a unique extended mapping class unless the surface is a sphere with at most four punctures or a torus with at most two punctures ... More
Description of limits of ranges of iterations of stochastic integral mappings of infinitely divisible distributionsDec 01 2010For infinitely divisible distributions $\rho$ on $\mathbb{R}^d$ the stochastic integral mapping $\Phi_f\rho$ is defined as the distribution of improper stochastic integral $\int_0^{\infty-} f(s) dX_s^{(\rho)}$, where $f(s)$ is a non-random function and ... More
pi_*-kernels of Lie groupsAug 26 2002Oct 04 2002We study the group of homotopy classes of self maps of compact Lie groups which induce the trivial homomorphism on homotopy groups. We completely determine the groups for SU(3) and Sp(2). We investigate these groups for simple Lie groups in the cases ... More
Enumeration of Restricted Partition Pairs and Permutation Pairs via 0-1 TableauxAug 25 2010Aug 12 2014We use the 0-1 tableaux as a tool for enumerating permutations and partitions with restricted minima. The method used is extended for permutation pairs and partition pairs generated by a bipartite 0-1 tableaux.
Progressive quenching - Globally coupled modelOct 17 2017Jun 15 2018We study the processes in which fluctuating elements of a system are progressively fixed (quenched) while keeping the interaction with the remaining unfixed elements. If the interaction is global among the Ising spin elements and if the unfixed part is ... More
Plane curves which are quantum homogeneous spacesOct 22 2018Let $\mathcal{C}$ be a decomposable plane curve over an algebraically closed field $k$ of characteristic 0. That is, $\mathcal{C}$ is defined in $k^2$ by an equation of the form $g(x) = f(y)$, where $g$ and $f$ are polynomials of degree at least 2. We ... More
Weak formulation for singular diffusion equation with dynamic boundary conditionMay 07 2017In this paper, we propose a weak formulation of the singular diffusion equation subject to the dynamic boundary condition. The weak formulation is based on a reformulation method by an evolution equation including the subdifferential of a governing convex ... More