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Noncommutative Solitons in a Supersymmetric Chiral Model in 2+1
Dimensions | We consider a supersymmetric Bogomolny-type model in 2+1 dimensions
originating from twistor string theory. By a gauge fixing this model is reduced
to a modified U(n) chiral model with N<=8 supersymmetries in 2+1 dimensions.
After a Moyal-type deformation of the model, we employ the dressing method to
explicitly construct multi-soliton configurations on noncommutative R^{2,1} and
analyze some of their properties.
|
Gravitational Duality Transformations on (A)dS4 | We discuss the implementation of electric-magnetic duality transformations in
four-dimensional gravity linearized around Minkowski or (A)dS4 backgrounds. In
the presence of a cosmological constant duality generically modifies the
Hamiltonian, nevertheless the bulk dynamics is unchanged. We pay particular
attention to the boundary terms generated by the duality transformations and
discuss their implications for holography.
|
Effect of transition-metal elements on the electronic properties of
quasicrystals and complex aluminides | In this paper, we briefly present our work on the role of transition-metal
element in electronic structure and transport properties of quasicrystals and
related complex phases. Several Parts of these works have been done or
initiated in collaboration with Prof. T. Fujiwara.
|
Neutrinos and Non-proliferation in Europe | Triggered by the demand of the IAEA, neutrino physicists in Europe involved
with the Double Chooz experiment are studying the potential of neutrino
detection to monitor nuclear reactors. In particular a new set of experiments
at the ILL is planned to improve the knowledge of the neutrino spectrum emitted
in the fission of 235U and 239Pu.
|
Kinks and Particles in Non-integrable Quantum Field Theories | In this talk we discuss an elementary derivation of the semi-classical
spectrum of neutral particles in two field theories with kink excitations. We
also show that, in the non-integrable cases, each vacuum state cannot
generically support more than two stable particles, since all other neutral
exitations are resonances, which will eventually decay.
|
The Expanding Photosphere Method: Progress and Problems | Distances to well-observed Type II-P SNe are determined from an updated
version of the Expanding Photosphere Method (EPM), based on recent theoretical
models. The new EPM distances show good agreement with other independent
distances to the host galaxies without any significant systematic bias,
contrary to earlier results in the literature. The accuracy of the method is
comparable with that of the distance measurements for Type Ia SNe.
|
Mixed chemistry phenomenon during late stages of stellar evolution | We discuss phenomenon of simultaneous presence of O- and C-based material in
surroundings of evolutionary advanced stars. We concentrate on silicate carbon
stars and present observations that directly confirm the binary model scenario
for them. We discuss also class of C-stars with OH emission detected, to which
some [WR] planetary nebulae do belong.
|
Frequency modulation Fourier transform spectroscopy | A new method, FM-FTS, combining Frequency Modulation heterodyne laser
spectroscopy and Fourier Transform Spectroscopy is presented. It provides
simultaneous sensitive measurement of absorption and dispersion profiles with
broadband spectral coverage capabilities. Experimental demonstration is made on
the overtone spectrum of C2H2 in the 1.5 $\mu$m region.
|
Spectral action on noncommutative torus | The spectral action on noncommutative torus is obtained, using a
Chamseddine--Connes formula via computations of zeta functions. The importance
of a Diophantine condition is outlined. Several results on holomorphic
continuation of series of holomorphic functions are obtained in this context.
|
The Lifshitz-Slyozov-Wagner equation for reaction-controlled kinetics | We rigorously derive a weak form of the Lifshitz-Slyozov-Wagner equation as
the homogenization limit of a Stefan-type problem describing
reaction-controlled coarsening of a large number of small spherical particles.
Moreover, we deduce that the effective mean-field description holds true in the
particular limit of vanishing surface-area density of particles.
|
Canonical singular hermitian metrics on relative canonical bundles | We introduce a new class of canonical AZD's (called the supercanonical AZD's)
on the canonical bundles of smooth projective varieties with pseudoeffective
canonical classes. We study the variation of the supercanonical AZD
$\hat{h}_{can}$ under projective deformations and give a new proof of the
invariance of plurigenera.
|
$\Bz\to\pip\pim\piz$ Time Dependent Dalitz analysis at BaBar | I present here results of a time-dependent analysis of the Dalitz structure
of neutral $B$ meson decays to
$\pip\pim\piz$ from a dataset of 346 million $B \bar B$ pairs collected at
the $\Upsilon(4S)$ center of mass energy by the BaBar detector at the SLAC
PEP-II $e^+e^-$ accelerator. No significant CP violation effects are observed
and 68% confidence interval is derived on the weak angle $\alpha$ to be
[75$^o$,152$^o$]
|
A non-perturbative proof of Bertrand's theorem | We discuss an alternative non-perturbative proof of Bertrand's theorem that
leads in a concise way directly to the two allowed fields: the newtonian and
the isotropic harmonic oscillator central fields.
|
Membrane in M5-branes Background | In this paper, we investigate the properties of a membrane in the M5-brane
background. Through solving the classical equations of motion of the membrane,
we can understand the classical dynamics of the membrane in this background.
|
Counting characters in linear group actions | Let $G$ be a finite group and $V$ be a finite $G$--module. We present upper
bounds for the cardinalities of certain subsets of $\Irr(GV)$, such as the set
of those $\chi\in\Irr(GV)$ such that, for a fixed $v\in V$, the restriction of
$\chi$ to $<v>$ is not a multiple of the regular character of $<v>$. These
results might be useful in attacking the non--coprime $k(GV)$--problem.
|
Effective interactions from q-deformed inspired transformations | From the mass term for the transformed quark fields, we obtain effective
contact interactions of the NJL type. The parameters of the model that maps a
system of non-interacting transformed fields into quarks interacting via NJL
contact terms are discussed.
|
Magnetospectroscopy of epitaxial few-layer graphene | The inter-Landau level transitions observed in far-infrared transmission
experiments on few-layer graphene samples show a behaviour characteristic of
the linear dispersion expected in graphene. This behaviour persists in
relatively thick samples, and is qualitatively different from that of thin
samples of bulk graphite.
|
A new approach to mutual information | A new expression as a certain asymptotic limit via "discrete micro-states" of
permutations is provided to the mutual information of both continuous and
discrete random variables.
|
A Low Complexity Algorithm and Architecture for Systematic Encoding of
Hermitian Codes | We present an algorithm for systematic encoding of Hermitian codes. For a
Hermitian code defined over GF(q^2), the proposed algorithm achieves a run time
complexity of O(q^2) and is suitable for VLSI implementation. The encoder
architecture uses as main blocks q varying-rate Reed-Solomon encoders and
achieves a space complexity of O(q^2) in terms of finite field multipliers and
memory elements.
|
The local structure of conformally symmetric manifolds | This is a final step in a local classification of pseudo-Riemannian manifolds
with parallel Weyl tensor that are not conformally flat or locally symmetric.
|
Solvability of linear equations within weak mixing sets | We introduce a new class of "random" subsets of natural numbers, WM sets.
This class contains normal sets (sets whose characteristic function is a normal
binary sequence). We establish necessary and sufficient conditions for
solvability of systems of linear equations within every WM set and within every
normal set. We also show that partition-regular system of linear equations with
integer coefficients is solvable in any WM set.
|
Three-dimensional effects in "atom diodes": atom-optical devices for
one-way motion | The ``atom diode'' is a laser device that lets the ground state atom pass in
one direction but not in the opposite direction. We examine three-dimensional
effects of that device for arbitrary atomic incidence angles on flat laser
sheets and set breakdown limiting angles and velocities. It is found that a
correct diodic behavior independent of the incident angle can be obtained with
blue detuned lasers.
|
Shocks in nonlocal media | We investigate the formation of collisionless shocks along the spatial
profile of a gaussian laser beam propagating in nonlocal nonlinear media. For
defocusing nonlinearity the shock survives the smoothing effect of the nonlocal
response, though its dynamics is qualitatively affected by the latter, whereas
for focusing nonlinearity it dominates over filamentation. The patterns
observed in a thermal defocusing medium are interpreted in the framework of our
theory.
|
Proper holomorphic mappings of the spectral unit ball | We prove an Alexander type theorem for the spectral unit ball $\Omega_n$
showing that there are no non-trivial proper holomorphic mappings in
$\Omega_n$, $n\geq 2$.
|
Parsimony via concensus | The parsimony score of a character on a tree equals the number of state
changes required to fit that character onto the tree. We show that for
unordered, reversible characters this score equals the number of tree
rearrangements required to fit the tree onto the character. We discuss
implications of this connection for the debate over the use of consensus trees
or total evidence, and show how it provides a link between incongruence of
characters and recombination.
|
Renormgroup origin and analysis of Split Higgsino scenario | We present a renormalization group motivation of scale hierarchies in SUSY
SU(5) model. The Split Higgsino scanrio with a high scale of the SUSY breaking
is considered in detail. Its manifestations in experiments are discussed.
|
Measurement of the Decay Constant $f_D{_S^+}$ using $D_S^+ --> ell^+ nu | We measure the decay constant fDs using the Ds -> l+ nu channel, where the l+
designates either a mu+ or a tau+, when the tau+ -> pi+ nu. Using both
measurements we find fDs = 274 +-13 +- 7 MeV. Combining with our previous
determination of fD+, we compute the ratio fDs/fD+ = 1.23 +- 0.11 +- 0.04. We
compare with theoretical estimates.
|
Orthogonality criterion for banishing hydrino states from standard
quantum mechanics | Orthogonality criterion is used to shown in a very simple and general way
that anomalous bound-state solutions for the Coulomb potential (hydrino states)
do not exist as bona fide solutions of the Schr\"{o}dinger, Klein-Gordon and
Dirac equations.
|
Skew-Hadamard matrices of orders 188 and 388 exist | We construct several difference families on cyclic groups of orders 47 and
97, and use them to construct skew-Hadamard matrices of orders 188 and 388.
Such difference families and matrices are constructed here for the first time.
The matrices are constructed by using the Goethals-Seidel array.
|
On the HOMFLY and Tutte polynomials | A celebrated result of F. Jaeger states that the Tutte polynomial of a planar
graph is determined by the HOMFLY polynomial of an associated link. Here we are
interested in the converse of this result. We consider the question `to what
extent does the Tutte polynomial determine the HOMFLY polynomial of any knot?'
We show that the HOMFLY polynomial of a knot is determined by Tutte polynomials
of plane graphs associated to the knot.
|
Efficiency of thin film photocells | We propose a new concept for the design of high-efficiency photocells based
on ultra-thin (submicron) semiconductor films of controlled thickness. Using a
microscopic model of a thin dielectric layer interacting with incident
electromagnetic radiation we evaluate the efficiency of conversion of solar
radiation into the electric power. We determine the optimal range of parameters
which maximize the efficiency of such photovoltaic element.
|
Necessary optimality conditions for the calculus of variations on time
scales | We study more general variational problems on time scales. Previous results
are generalized by proving necessary optimality conditions for (i) variational
problems involving delta derivatives of more than the first order, and (ii)
problems of the calculus of variations with delta-differential side conditions
(Lagrange problem of the calculus of variations on time scales).
|
Bounds for Multiplicities of Unitary Representations of Cohomological
Type in Spaces of Cusp Forms | Let $\Goo$ be a semisimple real Lie group with unitary dual $\Ghat$. The goal
of this note is to produce new upper bounds for the multiplicities with which
representations $\pi \in \Ghat$ of cohomological type appear in certain spaces
of cusp forms on $\Goo$.
|
Reduced and Extended Weak Coupling Limit | We give an extended review of recent work on the extended weak coupling
limit. Background material on completely positive semigroups and their unitary
dilations is given, as well as a particularly easy construction of `quadratic
noises'.
|
A generalization of Chebyshev polynomials and non rooted posets | In this paper we give a generalization of Chebyshev polynomials and using
this we describe the M\"obius function of the generalized subword order from a
poset {a1,...as,c |ai<c}, which contains an affirmative answer for the
conjecture by Bj\"orner, Sagan, Vatter.[5,10]
|
Finite dimensionality of 2-D micropolar fluid flow with periodic
boundary conditions | This paper is devoted to describe the finite-dimensionality of a
two-dimensional micropolar fluid flow with periodic boundary conditions. We
define the notions of determining modes and nodes and estimate the number of
them, we also estimate the dimension of the global attractor. Finally we
compare our results with analogous results for Navier-Stokes equation.
|
Birth, survival and death of languages by Monte Carlo simulation | Simulations of physicists for the competition between adult languages since
2003 are reviewed. How many languages are spoken by how many people? How many
languages are contained in various language families? How do language
similarities decay with geographical distance, and what effects do natural
boundaries have? New simulations of bilinguality are given in an appendix.
|
Photoproduction of pi0 omega off protons for E(gamma) < 3 GeV | Differential and total cross-sections for photoproduction of gamma proton to
proton pi0 omega and gamma proton to Delta+ omega were determined from
measurements of the CB-ELSA experiment, performed at the electron accelerator
ELSA in Bonn. The measurements covered the photon energy range from the
production threshold up to 3GeV.
|
Neel order in the two-dimensional S=1/2 Heisenberg Model | The existence of Neel order in the S=1/2 Heisenberg model on the square
lattice at T=0 is shown using inequalities set up by Kennedy, Lieb and Shastry
in combination with high precision Quantum Monte Carlo data.
|
$C^r$-Lohner algorithm | We present a Lohner type algorithm for the computation of rigorous bounds for
solutions of ordinary differential equations and its derivatives with respect
to initial conditions up to arbitrary order. As an application we prove the
existence of multiple invariant tori around some elliptic periodic orbits for
the pendulum equation with periodic forcing and for Michelson system.
|
Circuit QED with a Flux Qubit Strongly Coupled to a Coplanar
Transmission Line Resonator | We propose a scheme for circuit quantum electrodynamics with a
superconducting flux-qubit coupled to a high-Q coplanar resonator. Assuming
realistic circuit parameters we predict that it is possible to reach the strong
coupling regime. Routes to metrological applications, such as single photon
generation and quantum non-demolition measurements are discussed.
|
Zero bias anomaly out of equilibrium | The non-equilibrium zero bias anomaly (ZBA) in the tunneling density of
states of a diffusive metallic film is studied. An effective action describing
virtual fluctuations out-of-equilibrium is derived. The singular behavior of
the equilibrium ZBA is smoothed out by real processes of inelastic scattering.
|
Acceleration and localization of matter in a ring trap | A toroidal trap combined with external time-dependent electric field can be
used for implementing different dynamical regimes of matter waves. In
particular, we show that dynamical and stochastic acceleration, localization
and implementation of the Kapitza pendulum can be originated by means of proper
choice of the external force.
|
Computation of Power Loss in Likelihood Ratio Tests for Probability
Densities Extended by Lehmann Alternatives | We compute the loss of power in likelihood ratio tests when we test the
original parameter of a probability density extended by the first Lehmann
alternative.
|
A note on higher-order differential operations | In this paper we consider successive iterations of the first-order
differential operations in space ${\bf R}^3.$
|
Binary Systems as Test-beds of Gravity Theories | We review the general relativistic theory of the motion, and of the timing,
of binary systems containing compact objects (neutron stars or black holes).
Then we indicate the various ways one can use binary pulsar data to test the
strong-field and/or radiative aspects of General Relativity, and of general
classes of alternative theories of relativistic gravity.
|
Some combinatorial aspects of differential operation compositions on
space $R^n$ | In this paper we present a recurrent relation for counting meaningful
compositions of the higher-order differential operations on the space $R^{n}$
(n=3,4,...) and extract the non-trivial compositions of order higher than two.
|
Hyperbolicity in unbounded convex domains | We provide several equivalent characterizations of Kobayashi hyperbolicity in
unbounded convex domains in terms of peak and anti-peak functions at infinity,
affine lines, Bergman metric and iteration theory.
|
Actions for the Bosonic String with the Curved Worldsheet | At first we introduce an action for the string, which leads to a worldsheet
that always is curved. For this action we study the Poincar\'e symmetry and the
associated conserved currents. Then, a generalization of the above action,
which contains an arbitrary function of the two-dimensional scalar curvature,
will be introduced. An extra scalar field enables us to modify these actions to
Weyl invariant models.
|
General Relativity Today | After recalling the conceptual foundations and the basic structure of general
relativity, we review some of its main modern developments (apart from
cosmology) : (i) the post-Newtonian limit and weak-field tests in the solar
system, (ii) strong gravitational fields and black holes, (iii) strong-field
and radiative tests in binary pulsar observations, (iv) gravitational waves,
(v) general relativity and quantum theory.
|
A procedure for finding the k-th power of a matrix | We give a new procedure in Maple for finding the k-th power of a martix. The
algorithm is based on the article [1].
|
Chemical Evolution | In this series of lectures we first describe the basic ingredients of
galactic chemical evolution and discuss both analytical and numerical models.
Then we compare model results for the Milky Way, Dwarf Irregulars, Quasars and
the Intra-Cluster- Medium with abundances derived from emission lines. These
comparisons allow us to put strong constraints on the stellar nucleosynthesis
and the mechanisms of galaxy formation.
|
Convergence of a finite volume scheme for the incompressible fluids | We consider a finite volume scheme for the two-dimensional incompressible
Navier-Stokes equations. We use a triangular mesh. The unknowns for the
velocity and pressure are respectively piecewise constant and affine. We use a
projection method to deal with the incompressibility constraint. In a former
paper, the stability of the scheme has been proven. We infer from it its
convergence.
|
Fundamental solutions for a class of non-elliptic homogeneous
differential operators | We compute temperate fundamental solutions of homogeneous differential
operators with real-principal type symbols. Via analytic continuation of
meromorphic distributions, fundamental solutions for these non-elliptic
operators can be constructed in terms of radial averages and invariant
distributions on the unit sphere.
|
Nuclear forces from chiral effective field theory | In this lecture series, I present the recent progress in our understanding of
nuclear forces in terms of chiral effective field theory.
|
Dynamics of Bose-Einstein Condensates | We report on some recent results concerning the dynamics of Bose-Einstein
condensates, obtained in a series of joint papers with L. Erdos and H.-T. Yau.
Starting from many body quantum dynamics, we present a rigorous derivation of a
cubic nonlinear Schroedinger equation known as the Gross-Pitaevskii equation
for the time evolution of the condensate wave function.
|
An S_3-symmetric Littlewood-Richardson rule | The classical Littlewood-Richardson coefficients C(lambda,mu,nu) carry a
natural $S_3$ symmetry via permutation of the indices. Our "carton rule" for
computing these numbers transparently and uniformly explains these six
symmetries; previously formulated Littlewood-Richardson rules manifest at most
three of the six.
|
On the (3,N) Maurer-Cartan equation | Deformations of the 3-differential of 3-differential graded algebras are
controlled by the (3,N) Maurer-Cartan equation. We find explicit formulae for
the coefficients appearing in that equation, introduce new geometric examples
of N-differential graded algebras, and use these results to study N Lie
algebroids.
|
Local well-posedness of nonlinear dispersive equations on modulation
spaces | By using tools of time-frequency analysis, we obtain some improved local
well-posedness results for the NLS, NLW and NLKG equations with Cauchy data in
modulation spaces $M{p, 1}_{0,s}$.
|
Moduli spaces of rational tropical curves | This note is devoted to the definition of moduli spaces of rational tropical
curves with n marked points. We show that this space has a structure of a
smooth tropical variety of dimension n-3. We define the Deligne-Mumford
compactification of this space and tropical $\psi$-class divisors.
|
Structure of Strange Dwarfs with Color Superconducting Core | We study effects of two-flavor color superconductivity on the structure of
strange dwarfs, which are stellar objects with similar masses and radii with
ordinary white dwarfs but stabilized by the strange quark matter core. We find
that unpaired quark matter is a good approximation to the core of strange
dwarfs.
|
Counting on rectangular areas | In the first section of this paper we prove a theorem for the number of
columns of a rectangular area that are identical to the given one. In the next
section we apply this theorem to derive several combinatorial identities by
counting specified subsets of a finite set.
|
Bose-Einstein correlations of direct photons in Au+Au collisions at
$\sqrt{s_{NN}} = 200$ GeV | The current status of the analysis of direct photon Bose-Einstein
correlations in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV done by the PHENIX
collaboration is summarized. All possible sources of distortion of the
two-photon correlation function are discussed and methods to control them in
the PHENIX experiment are presented.
|
Normalized Ricci flow on nonparabolic surfaces | This paper studies normalized Ricci flow on a nonparabolic surface, whose
scalar curvature is asymptotically -1 in an integral sense. By a method
initiated by R. Hamilton, the flow is shown to converge to a metric of constant
scalar curvature -1. A relative estimate of Green's function is proved as a
tool.
|
Approximate Selection Rule for Orbital Angular Momentum in Atomic
Radiative Transitions | We demonstrate that radiative transitions with \Delta l = - 1 are strongly
dominating for all values of n and l, except small region where l << n.
|
Lessons Learned from the deployment of a high-interaction honeypot | This paper presents an experimental study and the lessons learned from the
observation of the attackers when logged on a compromised machine. The results
are based on a six months period during which a controlled experiment has been
run with a high interaction honeypot. We correlate our findings with those
obtained with a worldwide distributed system of lowinteraction honeypots.
|
Spectral perturbation bounds for selfadjoint operators | We give general spectral and eigenvalue perturbation bounds for a selfadjoint
operator perturbed in the sense of the pseudo-Friedrichs extension. We also
give several generalisations of the aforementioned extension. The spectral
bounds for finite eigenvalues are obtained by using analyticity and
monotonicity properties (rather than variational principles) and they are
general enough to include eigenvalues in gaps of the essential spectrum.
|
Non-monotone convergence in the quadratic Wasserstein distance | We give an easy counter-example to Problem 7.20 from C. Villani's book on
mass transport: in general, the quadratic Wasserstein distance between $n$-fold
normalized convolutions of two given measures fails to decrease monotonically.
|
Extension theorems of Sakai type for separately holomorphic and
meromorphic functions | We first exhibit counterexamples to some open questions related to a theorem
of Sakai.
Then we establish an extension theorem of Sakai type for separately
holomorphic/meromorphic functions.
|
Uniform measures and countably additive measures | Uniform measures are defined as the functionals on the space of bounded
uniformly continuous functions that are continuous on bounded uniformly
equicontinuous sets. If every cardinal has measure zero then every countably
additive measure is a uniform measure. The functionals sequentially continuous
on bounded uniformly equicontinuous sets are exactly uniform measures on the
separable modification of the underlying uniform space.
|
Reactor Monitoring with Neutrinos | The fundamental knowledge on neutrinos acquired in the recent years open the
possibility of applied neutrino physics. Among it the automatic and non
intrusive monitoring of nuclear reactor by its antineutrino signal could be
very valuable to IAEA in charge of the control of nuclear power plants. Several
efforts worldwide have already started.
|
Gorenstein locus of minuscule Schubert varieties | In this article, we describe explicitely the Gorenstein locus of all
minuscule Schubert varieties. This proves a special case of a conjecture of A.
Woo and A. Yong (see math.AG/0603273) on the Gorenstein locus of Schubert
varieties.
|
Higher spin algebras as higher symmetries | The exhaustive study of the rigid symmetries of arbitrary free field theories
is motivated, along several lines, as a preliminary step in the completion of
the higher-spin interaction problem in full generality. Some results for the
simplest example (a scalar field) are reviewed and commented along these lines.
|
A variation of Gronwall's lemma | We prove a variation of Gronwall's lemma.
|
When the Cramer-Rao Inequality provides no information | We investigate a one-parameter family of probability densities (related to
the Pareto distribution, which describes many natural phenomena) where the
Cramer-Rao inequality provides no information.
|
Analytic solutions for marginal deformations in open superstring field
theory | We extend the calculable analytic approach to marginal deformations recently
developed in open bosonic string field theory to open superstring field theory
formulated by Berkovits. We construct analytic solutions to all orders in the
deformation parameter when operator products made of the marginal operator and
the associated superconformal primary field are regular.
|
Theoretical Status of Pentaquarks | We review the current status of the theoretical pentaquark search from the
direct QCD calculation. The works from the QCD sum rule and the lattice QCD in
the literature are carefully examined. The importance of the framework which
can distinguish the exotic pentaquark state (if any) from the NK scattering
state is emphasized.
|
The Einstein-Varicak Correspondence on Relativistic Rigid Rotation | The historical significance of the problem of relativistic rigid rotation is
reviewed in light of recently published correspondence between Einstein and the
mathematician Vladimir Varicak from the years 1909 to 1913.
|
The dissolution of the vacancy gas and grain boundary diffusion in
crystalline solids | Based on the formula for the number density of vacancies in a solid under the
stress or tension, the model of grain boundary diffusion in crystalline solids
is developed. We obtain the activation energy of grain boundary diffusion
(dependent on the surface tension or the energy of the grain boundary) and also
the distributions of vacancies and the diffusing species in the vicinity of the
grain boundary.
|
Form factors of the exotic baryons with isospin I=5/2 | The electromagnetic form factors of the exotic baryons are calculated in the
framework of the relativistic quark model at small and intermediate momentum
transfer. The charge radii of the E+++ baryons are determined.
|
Compatibility of radial, Lorenz and harmonic gauges | We observe that the radial gauge can be consistently imposed \emph{together}
with the Lorenz gauge in Maxwell theory, and with the harmonic traceless gauge
in linearized general relativity. This simple observation has relevance for
some recent developments in quantum gravity where the radial gauge is
implicitly utilized.
|
Stable algebras of entire functions | Suppose that $h$ and $g$ belong to the algebra $\B$ generated by the rational
functions and an entire function $f$ of finite order on ${\Bbb C}^n$ and that
$h/g$ has algebraic polar variety. We show that either $h/g\in\B$ or
$f=q_1e^p+q_2$, where $p$ is a polynomial and $q_1,q_2$ are rational functions.
In the latter case, $h/g$ belongs to the algebra generated by the rational
functions, $e^p$ and $e^{-p}$.
|
Generic character sheaves on disconnected groups and character values | We relate a generic character sheaf on a disconnected reductive group with a
character of a representation of the rational points of the group over a finite
field extending a result known in the connected case.
|
On the choice of coarse variables for dynamics | Two ideas for the choice of an adequate set of coarse variables allowing
approximate autonomous dynamics for practical applications are presented. The
coarse variables are meant to represent averaged behavior of a fine-scale
autonomous dynamics.
|
Constructions of Kahler-Einstein metrics with negative scalar curvature | We show that on Kahler manifolds with negative first Chern class, the
sequence of algebraic metrics introduced by H. Tsuji converges uniformly to the
Kahler-Einstein metric. For algebraic surfaces of general type and orbifolds
with isolated singularities, we prove a convergence result for a modified
version of Tsuji's iterative construction.
|
A Denjoy Theorem for commuting circle diffeomorphisms with mixed Holder
derivatives | We prove that if d is an integer number bigger than 1 and f_1,...,f_d are
commuting circle diffeomorphisms respectively of class C^(1+\tau_k), where
\tau_1 + ... + \tau_k > 1, then these maps are simultaneously conjugate to
rotations provided that their rotation numbers are independent over the
rationals.
|
Explicit HRS-Tilting | For an abelian category $A$ equipped with a torsion pair, we give an explicit
description for the abelian category $B$ introduced by Happel-Reiten-Smalo, and
also for the category of chain complexes $Ch(B)$ and the derived category
$D(B)$ of $B$. We also describe the DG structure on $Ch(B)$. As a consequence,
we find new proofs of certain results of Happel-Reiten-Smalo. The main
ingredient is the category of {\em decorated} complexes.
|
Lectures on derived and triangulated categories | These notes are meant to provide a rapid introduction to triangulated
categories. We start with the definition of an additive category and end with a
glimps of tilting theory. Some exercises are included.
|
Flops connect minimal models | A remark on a paper by Birkar-Cascini-Hacon-McKernan.
|
A product formula for volumes of varieties | A simple application of the semipositivity.
|
An Alternative Topological Field Theory of Generalized Complex Geometry | We propose a new topological field theory on generalized complex geometry in
two dimension using AKSZ formulation. Zucchini's model is $A$ model in the case
that the generalized complex structuredepends on only a symplectic structure.
Our new model is $B$ model in the case that the generalized complex structure
depends on only a complex structure.
|
Curvature estimates for Weingarten hypersurfaces in Riemannian manifolds | We prove curvature estimates for general curvature functions. As an
application we show the existence of closed, strictly convex hypersurfaces with
prescribed curvature $F$, where the defining cone of $F$ is $\C_+$. $F$ is only
assumed to be monotone, symmetric, homogeneous of degree 1, concave and of
class $C^{m,\al}$, $m\ge4$.
|
Etched Glass Surfaces, Atomic Force Microscopy and Stochastic Analysis | The effect of etching time scale of glass surface on its statistical
properties has been studied using atomic force microscopy technique. We have
characterized the complexity of the height fluctuation of a etched surface by
the stochastic parameters such as intermittency exponents, roughness, roughness
exponents, drift and diffusion coefficients and find their variations in terms
of the etching time.
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Topology of spaces of equivariant symplectic embeddings | We compute the homotopy type of the space of T^n-equivariant symplectic
embeddings from the standard 2n-dimensional ball of some fixed radius into a
2n-dimensional symplectic-toric manifold M, and use this computation to define
a Z-valued step function on the positive real line which is an invariant of the
symplectic-toric type of M. We conclude with a discussion of the partially
equivariant case of this result.
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Higher dimensional conundra | We study asymptotics of various Euclidean geometric phenomena as the
dimension tend to infinity.
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Entangling and disentangling capacities of nonlocal maps | Entangling and disentangling capacities are the key manifestation of the
nonlocal content of a quantum operation. A lot of effort has been put recently
into investigating (dis)entangling capacities of unitary operations, but very
little is known about capacities of non-unitary operations. Here we investigate
(dis)entangling capacities of unital CPTP maps acting on two qubits.
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Black Hole's Life at colliders | In the series of papers by Ida, Oda and Park, the complete description of
Hawking radiation to the brane localized Standard Model fields from mini black
holes in the low energy gravity scenarios are obtained. Here we briefly review
what we have learned in those papers.
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Working with 2s and 3s | We establish an equivalent condition to the validity of the Collatz
conjecture, using elementary methods. We derive some conclusions and show
several examples of our results. We also offer a variety of exercises, problems
and conjectures.
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Decartes' Perfect Lens | We give a new, elementary, purely analytical development of
\textsc{Descartes}' theorem that a smooth connected surface is a perfect
focusing lens if and only if it is a connected subset of the ovoid obtained by
revolving a cartesian oval around its axis of symmetry.
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Comment on "Chiral Suppression of Scalar Glueball Decay" | Comment on ``Chiral Suppression of Scalar Glueball Decay''
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