January 2002 arXiv papers — page 25

Burt A. Ovrut

We present three lectures on heterotic M-theory and a fourth lecture extending this theory to more general orbifolds. In Lecture 1, Horava-Witten theory is briefly discussed. We then compactify this theory on Calabi-Yau threefolds, choosing the "standard" embedding of the spin connection in the gauge connection. We derive, in detail, both the five-di

A. A. Deriglazov

It is shown that quantum mechanics on noncommutative spaces (NQM) can be obtained by the canonical quantization of some underlying second class constrained system formulated in extended configuration space. It leads, in particular, to an intriguing possibility of quantization in terms of the initial (noncommutative) variables. Two different formulations are

P. Shukla, A. K. Mohanty

The scenario of homogeneous nucleation is investigated for a first order quark-hadron phase transition in a rapidly expanding background of quark gluon plasma. It is found that significant supercooling is possible before hadronization begins. This study also suggests that spinodal decomposition competes with nucleation and may provide an alternative mechanis

P. Shukla

The lattice data for $N_f=2$ and $N_f=3$ based on staggered fermion formulations have been parameterized using a phenomenological equation of state for noninteracting but massive quasiparticles. Such a model would be a preferable starting point for phenomenological hadronization models and for a description of the strongly interacting matter near the phase t

Elena Gubankova

We analyze the chiral symmetry breaking of QCD in the Coulomb gauge. Using flow equations, we derive the renormalized gap equation and the Bethe-Salpeter equation and show that they are finite in both UV and IR regions. No additional UV renormalization is required in the chiral limit. We take into account the hyperfine interaction as well as chiral symmetry

Charles H. Bennett, John A. Smolin

Random beacons-information sources that broadcast a stream of random digits unknown by anyone beforehand-are useful for various cryptographic purposes. But such beacons can be easily and undetectably sabotaged, so that their output is known beforehand by a dishonest party, who can use this information to defeat the cryptographic protocols supposedly protecte

N. Stefanakis

We calculate the tunneling conductance spectra of a normal-metal/insulator/triplet superconductor using the Blonder-Tinkham-Klapwijk (BTK) formulation. Possible states for the superconductor are considered with horizontal lines of nodes, breaking the time reversal symmetry. These results would be useful to discriminate between pairing states in superonductor

E. Rozenberg, M. Auslender

In a recent paper (Michalopolou A., Syskakis E. and Papastaikoudis C., 2001 J. Phys.: Cond. Mat. 13, 11615) the authors reported on the measurements of electrical resistivity and specific heat at zero magnetic field carried out on polycrystalline non-stoichiometric La_{0.95-x}Sr_{x}MnO_{3} manganites.In particular, they attributed the low temperature behavio

You-Quan Li

The Lieb-Schultz-Mattis theorem is extended to generalized Heisenberg models related to non-exceptional Lie algebras. It is shown that there are no energy gaps above the ground sates for SO(4), Sp(2) and SU(4) Heisenberg models, gaps are suspected to occur in SO(5) and SO(6) models. The nondegenerate ground state for these models is rigorously proven.

David Langlois

The purpose of this article is to give a brief account of what we hope to learn from the future CMB experiments, essentially from the point of view of primordial cosmology. After recalling what we have already learnt, the principles of parameter extraction from the data are summarized. The discussion is then devoted to the information we could gain about the

B. W. Jiang

Based on the space MSX observation in bands A(8$μ$m), C(12$μ$m), D(15$μ$m) and E(21$μ$m), and the ground SiO maser observation of evolved stars by the Nobeyama 45-m telescope in the v=1 and v=2 J=1-0 transitions, the relation between SiO maser emission and mid-IR continuum radiation is analyzed. The relation between SiO maser emission and the IR radiation in

Enrique Vazquez-Semadeni

I review recent results from numerical simulations on the structure and dynamics of the ISM, and attempt to put together a coherent dynamical scenario. In particular, I discuss results on 1) the spatial distribution of the gas components, showing that reasonable agreement between simulations and observations exists, but noting that in most models the compone

Timothy M. Braje, Roger W. Romani, Mallory S. E. Roberts, Nobuyuki Kawai

We report on Chandra imaging observations of the Galactic Unidentified $γ$-ray source GEV J1809-2327, comparing the X-ray images with new VLA 1.46 GHz and 4.86 GHz maps. The X-ray images reveal a point source connected to a non-thermal X-ray/radio nebula, supporting a pulsar/wind model for the $γ$-ray emitter. We also detect numerous X-ray sources from the y

Kai Neergaard

In a schematic model with equidistant fourfold degenerate single-nucleon levels, a conventional isovector pairing force and a symmetry force, the RPA correlation energy rises almost linearly with the isospin T, thus producing a Wigner term in accordance with the empirical proportionality of the symmetry energy to T(T+1).

S. O. Tagieva, E. Yazgan, A. Ankay

We examined the fall-back disk models, and in general accretion, proposed to explain the properties of anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs), and radio pulsars (PSRs). We checked the possibility of some gas remaining around the neutron star after the supernova explosion. We also compared AXPs and SGRs with the X-ray pulsars in X-ray bin

Antonio Accioly, Harold Blas

Up to now, the only known exact Foldy- Wouthuysen transformation (FWT) in curved space is that concerning Dirac particles coupled to static spacetime metrics. Here we construct the exact FWT related to a real spin-0 particle for the aforementioned spacetimes. This exact transformation exists independently of the value of the coupling between the scalar field

V. A. Saleev

We consider J/psi meson photoproduction on protons at high energies at the leading order in alpha_s using conventional parton model and k_t-factorization approach of QCD. It is shown that in the both cases the colour singlet mechanism gives correct description for experimental data from HERA for the total cross section and for the J/psi meson z-spectrum at r

P. Rozmej, M. Turek, R. Arvieu, I. S. Averbukh

Time evolution of wave packets built from the eigenstates of the Dirac equation for a hydrogenic system is considered. We investigate the space and spin motion of wave packets which, in the non-relativistic limit, are stationary states with a probability density distributed uniformly along the classical, elliptical orbit (elliptic WP). We show that the prece

Shamit Kachru, Michael Schulz, Sandip Trivedi

We study novel type IIB compactifications on the T^6/Z_2 orientifold. This geometry arises in the T-dual description of Type I theory on T^6, and one normally introduces 16 space-filling D3-branes to cancel the RR tadpoles. Here, we cancel the RR tadpoles either partially or fully by turning on three-form flux in the compact geometry. The resulting (super)po

M. T. Chefrour, L. Chetouani, L. Guechi

Using the so(2,1) Lie algebra and the Baker, Campbell and Hausdorff formulas, the Green's function for the class of the confluent Natanzon potentials is constructed straightforwardly. The bound-state energy spectrum is then determined. Eventually, the three-dimensional harmonic potential, the three-dimensional Coulomb potential and the Morse potential ma

A. M. Selvam

Dow Jones Index time series exhibit irregular or fractal fluctuations on all time scales from days, months to years. The nonlinear fluctuations are selfsimilar as exhibited in inverse power law form for power spectra of temporal fluctuations. Inverse power law form for power spectra of fractal fluctuations is generic to all dynamical systems in nature and is

Sam M. Austin

Studies in nuclear astrophysics have long been associated with long runs at small accelerators, measuring ever-decreasing cross sections as one approached (but rarely reached) the energy of reactions in stars. But in recent years pioneering studies have shown that studies at high-energy accelerators can often yield the same information, and in some important

Nikolai F. Rulkov

A simple model that replicates the dynamics of spiking and spiking-bursting activity of real biological neurons is proposed. The model is a two-dimensional map which contains one fast and one slow variable. The mechanisms behind generation of spikes, bursts of spikes, and restructuring of the map behavior are explained using phase portrait analysis. The dyna

Raissa M. D'Souza, Norman H. Margolus, Mark A. Smith

We introduce a simplified technique for incorporating diffusive phenomena into lattice-gas molecular dynamics models. In this method, spatial interactions take place one dimension at a time, with a separate fractional timestep devoted to each dimension, and with all dimensions treated identically. We show that the model resulting from this technique is equiv

Sebastien Boucksom

Using a result of Fujita on approximate Zariski decompositions and the singular version of Demailly's holomorphic Morse inequalities as obtained by Bonavero, we express the volume of a line bundle in terms of the absolutely continuous parts of all the positive curvature currents on it, with a way to pick an element among them which is most homogeneous wi

Z. Zakirova

In this note we find the metric of 6-dimensional h-space of the [33] type and then determine an important projective group characteristic of this h-space.

Lee Smolin

It is shown that the matrix models which give non-perturbative definitions of string and M theory may be interpreted as non-local hidden variables theories in which the quantum observables are the eigenvalues of the matrices while their entries are the non-local hidden variables. This is shown by studying the bosonic matrix model at finite temperature, with

Thomas Fischbacher

Five nontrivial stationary points are found for maximal gauged N=16 supergravity in three dimensions with gauge group $SO(8)\times SO(8)$ by restricting the potential to a submanifold of the space of $SU(3)\subset(SO(8)\times SO(8))_{\rm diag}$ singlets. The construction presented here uses the embedding of $E_{7(+7)}\subset E_{8(+8)}$ to lift the analysis o

H. Athar, G. -L. Lin

We discuss some motivations for detecting high-energy neutrinos through the pure electroweak processes such as $\barν_e e^-\to W^- $ and $\barν_e e^-\to W^-γ$. We argue that the latter process can be viewed as an enhancement to the former one. The event-rate enhancement is estimated.

Bernd Surrow

Phenomenological studies on the proton structure function F^2 have been carried out to investigate the behavior of F^2, i.e. its x and Q^2 dependence, in the transition from the deep-inelastic scattering region (Q^2 >> 1 GeV^2) to the photoproduction region (Q^2 approx. 0 GeV^2). An overview of various results of F^2 at low Q^2 is given. To quantify the beha

T. Montaruli, for ANTARES Collaboration

The ANTARES project aims at the construction of an underwater neutrino telescope at the scale of 0.1 km^2 2400 m deep in the Mediterranean Sea. After a 4-year R&D program, the ANTARES project has entered the construction phase which will be concluded by the end of 2004. The current status of the project is reported.

Qingshan Yuan, Thilo Kopp

Recent experiments in Pr(Nd)$_{0.5}$Ca$_{0.5}$MnO$_3$ thin films exhibited (multiple) reentrant charge ordering (CO) transitions with change of {\it temperature} T under fixed magnetic field H, which are in contrast to the results for the corresponding bulk materials. To explain the experimental findings, a model including the double-exchange mechanism, inte

Takao Morinari

We reexamine the possibility of d-wave superconductivity in the hole-doped two-dimensional Hubbard model. In terms of the gauge field description of the spin fluctuations, we show that d-wave superconductivity is unstable in the perturbative region with respect to the on-site Coulomb repulsion, U. Whereas in the region where d-wave superconductivity is possi

I. A. Lubashevsky, V. V. Gafiychuk, B. Y. Datsko

We analyze the effect of blood flow through large arteries of peripheral circulation on heat transfer in living tissue. Blood flow in such arteries gives rise to fast heat propagation over large scales, which is described in terms of heat superdiffusion. The corresponding bioheat heat equation is derived. In particular, we show that under local strong heatin

Hidetoshi Nishimori

Exact and/or rigorous results are reviewed for the Ising and XY/Villain spin glasses in finite dimensions, such as the exact energy, correlation identities and a functional relation between the distribution functions of ferromagnetic and spin glass order parameters. This last relation is useful to prove that the phase space is not complex on a line in the ph

T. Rupp, Y. Alhassid, S. Malhotra

We calculate the finite-temperature conductance peak-height distributions in Coublomb-blockade quantum dots in the limit where the inelastic scattering rate in the dot is large compared with the mean elastic tunneling rate. The relative reduction of the standard deviation of the peak-height distribution by a time-reversal symmetry-breaking magnetic field, wh

Q. D. Wang, E. V. Gotthelf, C. C. Lang

The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components of this emission, which is critical to understanding the high-energy phenomena and processes unique to this Galactic nu

R. Cruddace, W. Voges, H. Boehringer, C. A. Collins

A field of 1.013 ster in the ROSAT all-sky survey (RASS), centered on the south galactic pole (SGP), has been searched in a systematic, objective manner for clusters of galaxies. The procedure relied on a correlation of the X-ray positions and properties of ROSAT sources with the distribution of galaxies in the COSMOS digitised data base, which was obtained

Gy. M. Szabo, L. L. Kiss, K. Sarneczky, K. Sziladi

We discuss the morphology and spectrophotometry of 5 comets visible in August, 2001. We decompose comae into coma profiles and azimuthally renormalized images, in which general and local features are quantitatively comparable. Comet 19P/Borrelly showed a strong gas fan toward the solar direction, but no detectable gas in the tail. Dust in its inner coma was

Volker Bromm, Cathie J. Clarke

We explore a mechanism for the formation of the first globular clusters, operating during the assembly of dwarf galaxies at high redshifts, z > 10. The substructure in the dark matter and the corresponding potential wells are responsible for setting the cluster scale of ~10^5 M_sun. The second mass scale in the formation problem, the stellar scale of ~1 M_su

A. J. Barth

More than one third of all nearby galaxies show indications of low-luminosity nuclear activity. These low-luminosity AGNs (LLAGNs) are traditionally classified into a variety of categories depending on their forbidden-line ratios and on the presence or absence of broad-line emission. By analogy with Seyfert unification models, it is natural to ask whether th

Erich J. Mueller, Tin-Lun Ho

We consider the condensate wavefunction of a rapidly rotating two-component Bose gas with an equal number of particles in each component. If the interactions between like and unlike species are very similar (as occurs for two hyperfine states of $^{87}$Rb or $^{23}$Na) we find that the two components contain identical rectangular vortex lattices, where the u

Hitoshi Murayama

Neutrino physics is going through a revolutionary progress. In this talk I review what we have learned and why neutrino mass is so important. Neutrino masses and mixings are already shedding new insight into the origin of flavor. Given the evidences for neutrino mass, leptogenesis is gaining momentum as the origin of cosmic baryon asymmetry. Best of all, we

Einan Gardi, Johan Rathsman

Dressed Gluon Exponentiation (DGE) is used to calculate the thrust and the heavy-jet mass distributions in e+e- annihilation in the two-jet region. We perform a detailed analysis of power corrections, taking care of the effect of hadron masses on the measured observables. In DGE the Sudakov exponent is calculated in a renormalization-scale invariant way usin

Michal Fabinger

We construct a string theory realization of the 4+1d quantum Hall effect recently discovered by Zhang and Hu. The string theory picture contains coincident D4-branes forming an S^4 and having D0-branes (i.e. instantons) in their world-volume. The charged particles are modelled as string ends. Their configuration space approaches in the large n limit a CP^3,

Simon F. Portegies Zwart, Steve L. W. McMillan

We study the growth rate of stars via stellar collisions in dense star clusters, calibrating our analytic calculations with direct N-body simulations of up to 65536 stars, performed on the GRAPE family of special-purpose computers. We find that star clusters with initial half-mass relaxation times of about 25 Myr are dominated by stellar collisions, the firs

W. F. Chen, R. B. Mann

We investigate the ABJ anomaly in the framework of an effective field theory for a 3-brane scenario and show that the contribution from induced gravity on the brane depends on both the topological structure of the bulk space-time and the embedding of the brane in the bulk. This fact implies the existence of a non-trivial vacuum structure of bulk quantum grav

S. L. Dubovsky, V. A. Rubakov, S. M. Sibiryakov

We consider noncommutative gauge theories which have zero mass states propagating along both commutative and noncommutative dimensions. Solitons in these theories generically carry U(m) gauge group on their world-volume. From the point of view of string theory, these solitons correspond to ``branes within branes''. We show that once the world-volume

Edward A. Baltz, Geza Gyuk, Arlin Crotts

We provide a set of microlensing event rate maps for M31, the Andromeda Galaxy. Rates for M31 microlensing were calculated on the basis of a four component model of the lens and source populations: disk and bulge sources lensed by bulge, disk, M31 halo and Galactic halo lenses. We confirm the high rate gradient along the minor axis of M31 due to a dark halo

Vadim B. Kuznetsov

In the special case of zero square integral the Kowalevski gyrostat and Goryachev-Chaplygin gyrostat share a simple separation of variables originated from the 4x4 Lax matrix.

Hai-Yang Cheng, Kwei-Chou Yang

Weak radiative baryonic B decays $B\to\B_1\ov \B_2γ$ mediated by the electromagnetic penguin process $b\to sγ$ have appreciable rates larger than their two-body counterparts $B\to\B_1\ov \B_2$. The branching ratios for $B^-\toΛ\bar pγ$ and $B^-\toΞ^0\barΣ^-γ$ are sizable, falling into the range of $(1\sim 6)\times 10^{-6}$ with the value preferred to be on t

Y. S. Kim

Since Feynman proposed his parton model in 1969, one of the most pressing problems in high-energy physics has been whether partons are quarks. It is shown that the quark model and the parton model are two different manifestations of one covariant entity. The nature of transition from the confined quarks to plasma-like partons is studied in terms of the entro

Pavel Bleher, Xiaojun Di

We obtain exact analytical expressions for correlations between real zeros of the Kac random polynomial. We show that the zeros in the interval $(-1,1)$ are asymptotically independent of the zeros outside of this interval, and that the straightened zeros have the same limit translation invariant correlations. Then we calculate the correlations between the st

Nicolas Boulanger, Marc Henneaux, Peter van Nieuwenhuizen

We construct consistent interacting gauge theories for M conformal massless spin-2 fields ("Weyl gravitons") with the following properties: (i) in the free limit, each field fulfills the equation ${\cal B}^{μν} = 0$, where ${\cal B}^{μν}$ is the linearized Bach tensor, (ii) the interactions contain no more than four derivatives, just as the free acti

John McDonald

F-term hybrid inflation models in the context of supergravity generically have corrections to the inflaton mass squared of the order of H^{2} (the η-problem). In addition they have a problem with large deviations of the spectrum of density perturbations from scale-invariance due to non-renormalizable corrections to the superpotential. Here we show that an in

A. Garmash

We report on a study of three-body charmless decays B+ => K+h+h-$ based on a 29.1 fb^{-1} data sample collected with the Belle detector. With no assumptions on the intermediate mechanisms, the following three-body branching fractions have been measured for the first time: Br(B+ => K+pi-pi+) = (55.6\pm5.8\pm7.7)x10^{-6} and Br(B+ => K+K-K+) = (35.3\pm3.7\pm4.

Leonid Chuzhoy, Adi Nusser

We derive similarity solutions for the expansion of negative initial density perturbations δM/M \propto r^-s (s>0) in an Einstein-de Sitter universe filled with collisional baryonic gas and collisionless matter. The solutions are obtained for planar, cylindrical, and spherical perturbations. For steep perturbations, central cavities surrounded by over-dense

Stefan Weinzierl

Higher transcendental function occur frequently in the calculation of Feynman integrals in quantum field theory. Their expansion in a small parameter is a non-trivial task. We report on a computer program which allows the systematic expansion of certain classes of functions. The algorithms are based on the Hopf algebra of nested sums. The program is written

XuBo Zou, K. Pahlke, W. Mathis

We present a scheme to generate arbitrary superposition of the Dicke states of excitons in optically driven quantum dots. This proposal is based on a sequence of laser pulses, which are tuned appropriately to control transitions on Dicke state. It is shown that N laser pulses are needed to generate arbitrary superposition of the Dicke states of N quantum dot

S. Ansoldi, C. Castro, E. I. Guendelman, E. Spallucci

The spectrum of quenched Yang-Mills theory in the large-N limit displays strings and higher dimensional extended objects. The effective dynamics of string-like excitations is encoded into area preserving Schild action. In this letter, we bridge the gap between SU(N) gauge models and fully reparametrization invariant Nambu-Goto string models by introducing an

Wadim Zudilin

Applying Zeilberger's algorithm of creative telescoping to a family of certain very-well-poised hypergeometric series involving linear forms in Catalan's constant with rational coefficients, we obtain a second-order difference equation for these forms and their coefficients. As a consequence we obtain a new way of fast calculation of Catalan's co

Lay Nam Chang, Djordje Minic, Naotoshi Okamura, Tatsu Takeuchi

We investigate the effect of the minimal length uncertainty relation, motivated by perturbative string theory, on the density of states in momentum space. The relation is implemented through the modified commutation relation [x_i,p_j]=i hbar[(1 + beta p^2) delta_{ij} + beta' p_i p_j]. We point out that this relation, which is an example of an UV/IR relat

Hoang K. Nguyen, Sudip Chakravarty

We consider the effects of a perpendicular magnetic field on the d-density wave order and conclude that if the pseudogap phase in the cuprates is due to this order, then it is highly insensitive to the magnetic field in the underdoped regime, while its sensitivity increases as the gap vanishes in the overdoped regime. This appears to be consistent with the a

Robert Alicki

The theory of noncommutative dynamical entropy and quantum symbolic dynamics for quantum dynamical systems is analised from the point of view of quantum information theory. Using a general quantum dynamical system as a communication channel one can define different classical capacities depending on the character of resources applied for encoding and decoding

Arvind

The U(2) invariant approach is delineated for the pair coherent states to explore their squeezing properties. This approach is useful for a complete analysis of the squeezing properties of these two-mode states. We use the maximally compact subgroup U(2) of Sp(4,R) to mix the modes, thus allowing us to search over all possible quadratures for squeezing. The

Volodymyr Krasnoholovets

So-called hidden variables introduced in quantum mechanics by de Broglie and Bohm have changed their initial enigmatic meanings and acquired quite reasonable outlines of real and measurable characteristics. The start viewpoint was the following: All the phenomena, which we observe in the quantum world, should reflect structural properties of the real space.

Kyle Forinash

We present initial results regarding the existence, stability and interaction of linear and nonlinear vibrational modes in a system of two coupled, one dimensional lattices with unequal numbers of masses. The effects on these nonlinear modes of coupling a near continuum system to a discrete system using a nonlinear coupling are examined. This numerical model

Andrei Terebilo

This paper reports on Matlab Channel Access (MCA) Toolbox Matlab [1] interface to Epics Channel Access (CA) client library. We are developing the toolbox for SPEAR3 accelerator controls but it is of general use for accelerator and experimental physics applications programming. It is packaged as Matlab toolbox to allow easy development of complex CA client ap

Vladimir P. Garistov

Analysis of the collective structure of 0^{+} states in terms of phonon tations for great amount of nuclei is presented .It is shown that the rotational bands built on these states strongly depend on their structure. The spectrum of the bands is obtained by the application of the Nuclear Surface Oscillation /NSO/ model and assumption of "Kassini form&#34

M. Kortelainen, J. Suhonen

A reliable theoretical description of double-beta-decay processes needs a possibility to test the involved virtual transitions against experimental data. Unfortunately, only the lowest virtual transition can be probed by the traditional electron-capture or $β^-$-decay experiments. In this article we propose that calculated amplitudes for many virtual transit

Gregor Veble, Marko Robnik, Valery Romanovski

In this work we study the Wigner functions, which are the quantum analogues of the classical phase space density, and show how a full rigorous semiclassical scheme for all orders of \hbar can be constructed for them without referring to the actual coordinate space wavefunctions from which the Wigner functions are typically calculated. We find such a picture

G. M. Zaslavsky, M. Edelman

A family of the billiard-type systems with zero Lyapunov exponent is considered as an example of dynamics which is between the regular one and chaotic mixing. This type of dynamics is called ``pseudochaos''. We demonstrate how the fractional kinetic equation can be introduced for the pseudochaos and how the main critical exponents of the fractional k

Tingting Liu, Menzhao Qin

The multisymplectic structure of the KP equation is obtained directly from the variational principal. Using the covariant De Donder-Weyl Hamilton function theories, we reformulate the KP equation to the multisymplectic form which proposed by Bridges. From the multisymplectic equation, we can derive a multisymplectic numerical scheme of the KP equation which

Pavel Bleher, Alexander Its

We prove the existence of the double scaling limit in the unitary matrix model with quartic interaction, and we show that the correlation functions in the double scaling limit are expressed in terms of the integrable kernel determined by the psi-function for the Hastings-McLeod solution to the Painlevé II equation. The proof is based on the Riemann-Hilbert a

Shu-Chiuan Chang, Robert Shrock

We prove several theorems concerning Tutte polynomials $T(G,x,y)$ for recursive families of graphs. In addition to its interest in mathematics, the Tutte polynomial is equivalent to an important function in statistical physics, the Potts model partition function of the $q$-state Potts model, $Z(G,q,v)$, where $v$ is a temperature-dependent variable. We deter

Walter Appel, Michael K. -H. Kiessling

Relativistic massive Lorentz electrodynamics (LED) is studied in a ``gyroscopic setup'' where the electromagnetic fields and the particle spin are the only dynamical degrees of freedom. A rigorous proof of the global existence and uniqueness of the dynamics is given for essentially the whole range of field strengths reasonable for a classical theory.

J. van den Berg, A. A. Jarai

We study the following problem for critical site percolation on the triangular lattice. Let A and B be sites on a horizontal line e separated by distance n. Consider, in the half-plane above e, the lowest occupied crossing R from the half-line left of A to the half-line right of B. We show that the probability that R has a site at distance smaller than m fro

Morten Skarsholm Risager

We define the counting function for non-analytic (Maass) newforms of Hecke congruence groups_Gamma_0(M)_. We then calculate the three main terms of this counting function and give necessary and sufficient conditions on M for this counting function to have the same shape as if it were counting eigenvalues related to a cocompact group.

Jan Wierzba, Jaroslaw A. Wisniewski

We classify small contractions of (holomorphically) symplectic 4-folds.

Loring W. Tu

a 10-page biography of Raoul Bott followed by a 25-page discussion of his major papers

Philippe Caldero, Peter Littelmann

Let G be a complex semisimple Lie group. The aim of this article is to compare two basis for G-modules, namely the standard monomial basis and the dual canonical basis. In particular, we give a sufficient condition for a standard monomial to be an element of the dual canonical basis and vice versa.

S. A. Kudryavtsev

All varieties, extremal contractions, singularities are divided on exceptional and non-exceptional ones. Roughly speaking, there are the infinite families of non-exceptional varieties, extremal contractions or singularities and only the finite number of the types of exceptional ones. This subdivision is well demonstrated by the example of Du Val singularitie

Jussi Vaisala

Necessary and sufficient quantitative geometric conditions are given for an unbounded set A in a euclidean space R^n to have the following property with a given c > 0: For every s > 0 and for every s-nearisometry f: A -> R^n there is an isometry T: A -> R^n such that |Tx - fx| \le cs for all x in A.

Behrang Noohi

We study fundamental groups of algebraic stacks. We show that these fundamental groups carry an additional structure coming from the inertia groups. Then use this additional structure to analyze geometric/ topological properties of stacks. We give an explicit formula for the fundamental group of the coarse moduli space. Also, we use these additional structur

Misha Verbitsky

Let M be a hypercomplex Hermitian manifold, (M,I) the same manifold considered as a complex Hermitian with a complex structure I induced by the quaternions. The standard linear-algebraic construction produces a canonical nowhere degenerate (2,0)-form on (M,I). It is well known that M is hyperkaehler if and only if the form Ωis closed with respect to the de R

Adrian Butscher

Suppose $M_{1}$ and $M_{2}$ are two special Lagrangian submanifolds of $\Rtn$ with boundary that intersect transversally at one point $p$. The set $M_{1} \cup M_{2}$ is a singular special Lagrangian variety with an isolated singularity at the point of intersection. Suppose further that the tangent planes at the intersection satisfy an angle condition (which

K. Bobkov, L. Dolan

We compute the three-graviton tree amplitude in Type IIB superstring theory compactified to six dimensions using the manifestly (6d) supersymmetric Berkovits-Vafa-Witten worldsheet variables. We consider two cases of background geometry: the flat space example R6xK3, and the curved example AdS3xS3xK3 with Ramond flux, and compute the correlation functions in

L. P. Csernai, J. I. Kapusta, E. Osnes

The statics and dynamics of a surface separating two phases of a relativistic quantum field theory at or near the critical temperature typically make use of a free energy as a functional of an order parameter. This free energy functional also affords an economical description of states away from equilibrium. The similarities and differences between using a s

Elena Perazzi

We discuss a number of exact results in N=1 supersymmetric field theories. We review the results obtained by Seiberg in Super-Yang-Mills (SYM) theories with matter in fundamental representation. We then consider Kutasov-type SYM theories, which also contain matter in the adjoint representation and an appropriate tree--level superpotential. We finally focus o

D. V. Meshcheryakov, T. D. Meshcheryakova

Explicit solutions for one completely-integrable system of Calogero-Moser type in external fields are found in case of three and four interacting particles. Relation between coupling constant, initial values of coordinates and time of falling into the singularity of potential is derived.

Andrei Mikhailov

The strong form of the AdS/CFT correspondence implies that the leading $N$ expressions for the connected correlation functions of the gauge invariant operators in the free ${\cal N}=4$ supersymmetric Yang-Mills theory with the gauge group SU(N) correspond to the boundary S matrix of the classical interacting theory in the Anti de Sitter space. It was conject

Edward Witten

We argue that multi-trace interactions in quantum field theory on the boundary of AdS space can be incorporated in the AdS/CFT correspondence by using a more general boundary condition for the bulk fields than has been considered hitherto. We illustrate the procedure for a renormalizable four-dimensional field theory with a $(\Tr Φ^2)^2$ interaction. In this

F. Larios, M. A. Perez, G. Tavares-Velasco

It is shown that the rare decays $Z \to ν\bar{nu} γ$ and $Z \to ν\barν γγ$ are useful to put model-independent bounds on neutrino-one-photon and neutrino-two-photon interactions. The results are then used to constrain the $τ$ neutrino magnetic moment and the double radiative decay $ν_j \to ν_i γγ$. It is found that the decay $Z \to ν\bar{nu} γ$ gives a more

Tao Han, Bob McElrath

We study the observability of the $h\to μ^+μ^-$ decay in the Standard Model and the MSSM at the LHC. The observation of the $hμμ$ coupling is important to determine whether the Higgs particle that generates mass for the weak bosons is also responsible for mass generation of the second generation of fermions. We find that the signal via the gluon fusion chann

Don Colladay

To date, a significant effort has been made to adddress the Lorentz violating standard model in low-energy systems, but little is known about the ramifications for high-energy cross sections. In this talk, I discuss the modified Feynman rules that result when Lorentz violation is present and give the results of an explicit calculation for electron-positron a

M. Fiolhais, P. Alberto, J. Marques, B. Golli

A description of the Roper using the chiral chromodielectric model is presented and the transverse $A_{1/2}$ and the scalar $S_{1/2}$ helicity amplitudes for the electromagnetic Nucleon--Roper transition are obtained for small and moderate $Q^2$. The sign of the amplitudes is correct but the model predictions underestimate the data at the photon point. Our r

B. Pasquini, M. Traini, S. Boffi

Light-front Hamiltonian dynamics is used to relate low-energy constituent quark models to deep inelastic unpolarized structure functions of the nucleon. The approach incorporates the correct Pauli principle prescription consistently and it allows a transparent investigation of the effects due to the spin-dependent SU(6)-breaking terms in the quark model Hami

J. D. Vergados

Exotic dark matter together with the vacuum energy or cosmological constant seem to dominate in the Universe. An even higher density of such matter seems to be gravitationally trapped in the Galaxy. Thus its direct detection is central to particle physics and cosmology. Current supersymmetric models provide a natural dark matter candidate which is the lighte

Weizhen Deng, Xiaolin Chen, Dahai Lu, Liming Yang

The quark potential model is extended to include the sea quark excitation using the random phase approximation (RPA). The effective quark interaction preserves the important Quantum Chromodynamics (QCD) properties -- chiral symmetry and confinement simultaneously. A primary qualitive analysis shows that the $π$ meson as a well-known typical Goldstone boson a

Yong Zhou

This paper has been withdrawn by the author,due a immature idea.