October 2006 arXiv papers — page 31

Miguel Abreu, Gustavo Granja, Nitu Kitchloo

In this paper we study the topology of the space $\I_ω$ of complex structures compatible with a fixed symplectic form $ω$, using the framework of Donaldson. By comparing our analysis of the space $\I_ω$ with results of McDuff on the space $\cat J_ω$ of compatible almost complex structures on rational ruled surfaces, we find that $\I_ω$ is contractible in thi

A. H. Córsico, L. G. Althaus, M. M. Miller Bertolami, K. Werner

We present asteroseismological inferences on RX J2117.1+3412, the hottest known pulsating PG1159 star. Our results are based on full PG1159 evolutionary models recently presented by Miller Bertolami & Althaus (2006). We performed extensive computations of adiabatic g-mode pulsation periods on PG1159 evolutionary models with stellar masses ranging from 0.530

H. Casini, M. Huerta

The combination of the Lorentz symmetry and the strong subadditive property of the entropy leads to a c-theorem for the entanglement entropy in 1+1 dimensions. We present a simple derivation of this theorem and compare the associated c-functions with the Zamolodchikov's ones for the case of free fields. We discuss the various difficulties which obstacle

L. Hartmann, B. Kraus, H. -J. Briegel, W. Dür

We investigate the influence of memory errors in the quantum repeater scheme for long-range quantum communication. We show that the communication distance is limited in standard operation mode due to memory errors resulting from unavoidable waiting times for classical signals. We show how to overcome these limitations by (i) improving local memory, and (ii)

Laszlo B. Kish

Recently, we proposed a classical communicator which was inspired by the Kirchhoff-loop-Johnson-like-Noise (KLJN) communicator and was claimed totally secure. Here we withdraw this claim and prove that, similarly to earlier intuitive suspicions, a wave-based classical communicator can never be totally secure.

Thomas Schaefer

We review many body calculations of the equation of state of dilute neutron matter in the context of effective field theories of the nucleon-nucleon interaction.

G. L. Celardo, F. M. Izrailev, V. G. Zelevinsky, G. P. Berman

We study the statistical properties of resonance widths and spacings in an open system of interacting fermions at the transition between isolated and overlapping resonances, where a radical change in the width distribution occurs. Our main interest is to reveal how this transition is influenced by the onset of chaos in the internal dynamics as the strength o

D. V. Bisikalo, A. A. Boyarchuk, E. Yu. Kilpio, N. A. Tomov

Two-dimensional gas-dynamical modeling of the mass-flow structure is used to study the outburst development in the classical symbiotic star Z And. The stage-by-stage rise of the light during the outburst can be explained in the framework of the colliding winds model. We suggest a scenario for the development of the outburst and study the possible influence o

J. L. Diaz-Cruz, A. Rosado

We obtain the mass spectrum and the Higgs self-coupling of the two Higgs doublet model (THDM) in an alternative unification scenario where the parameters of the Higgs potential $λ_i$ ($i=1,2,3,4,5$) are determined by imposing their unification with the electroweak gauge couplings. An attractive feature of this scenario is the possibility to determine the Hig

Fehmi Ben Abdesslem, Luigi Iannone, Marcelo Dias de Amorim, Katia Obraczka

This paper introduces Prawn, a tool for prototyping communication protocols over IEEE 802.11 networks. Prawn allows researchers to conduct both functional assessment and performance evaluation as an inherent part of the protocol design process. Since Prawn runs on real IEEE 802.11 nodes, prototypes can be evaluated and adjusted under realistic conditions. On

Jens Küster, Gernot Münster

The profile of interfaces separating different phases of statistical systems is investigated in the framework of renormalized field theory. The profile function is calculated analytically in the local potential approximation, using the effective potential to two loops. It can be interpreted as an intrinsic interfacial profile. The loop corrections to the lea

Jeong-Hyuck Park, Dimitrios Tsimpis

Putting a twisted version of N=4 super Yang-Mills on a curved four-dimensional manifold generically breaks all conformal supersymmetries. In the special case where the four-manifold is a cone, we show that exactly two conformal supercharges remain unbroken. We construct an off-shell formulation of the theory such that the two unbroken conformal supercharges

Guido Altarelli

At the School I gave three lectures on neutrino masses and mixings. Much of the material covered in my first two lectures is written down in a review on the subject that I published not long ago with F. Feruglio \cite{rev}. Here, I make a relatively short summary (with updates) of the content of my first two lectures, referring to our review for a more detai

A. M. Moro, M. Rodriguez-Gallardo, R. Crespo, I. J. Thompson

Benchmark calculations are performed aiming to test the use of two different pseudo-state bases on the the Multiple Scattering expansion of the total Transition amplitude (MST) scattering framework. Calculated differential cross sections for p-6He inelastic scattering at 717 MeV/u show a good agreement between the observables calculated in the two bases. Thi

Francesco Fucito, Jose F. Morales, Rubik Poghossian

We compute the instanton partition function for ${\cal N}=4$ U(N) gauge theories living on toric varieties, mainly of type $\R^4/Γ_{p,q}$ including $A_{p-1}$ or $O_{\PP_1}(-p)$ surfaces. The results provide microscopic formulas for the partition functions of black holes made out of D4-D2-D0 bound states wrapping four-dimensional toric varieties inside a Cala

Jussi M. Kumpula, Jari Saramaki, Kimmo Kaski, Janos Kertesz

According to Fortunato and Barthelemy, modularity-based community detection algorithms have a resolution threshold such that small communities in a large network are invisible. Here we generalize their work and show that the q-state Potts community detection method introduced by Reichardt and Bornholdt also has a resolution threshold. The model contains a pa

Wojciech De Roeck, Christian Maes

Recent advances in nonequilibrium statistical mechanics shed new light on the ratchet effect. The ratchet motion can thus be understood in terms of symmetry (breaking) considerations. We introduce an additional symmetry operation besides time-reversal, that effectively reverses the nonequilibrium driving. That operation of field-reversal combined with time-r

Subhrajyoti Biswas, Abhee K. Dutt-Mazumder

We estimate exclusive density and asymmetry parameter dependent dispersion relations of various charged states of pions in asymmetric nuclear matter. The possibility of matter induced mixing of $π^0$ with $η$ is clearly exposed with the further mass modification of $π^0$ meson due to mixing. Asymmetry driven mass splitting and mixing amplitude are of the sam

Tomohiro Matsuda

The scenario of brane inflation without using the conventional slow-roll approximations has been investigated. Based on the mechanism of generating the curvature perturbations at the end of inflation, a new brane inflation paradigm was developed. The conditions for making a sufficiently large enough number of e-foldings and for generating the curvature pertu

Roberto Balbinot, Serena Fagnocchi, Alessandro Fabbri

Using methods developed in Quantum Field Theory in curved space we can estimate the effects of the inhomogeneities and of a non vanishing velocity on the depletion of a Bose Einstein condensate within the hydrodynamical approximation.

M. G. Guarcello, L. Prisinzano, G. Micela, F. Damiani

Context: the observation of young stars with circumstellar disks suggests that the disks are dissipated, starting from the inner region, by the radiation of the central star and eventually by the formation of rocky planetesimals, over a time scale of several million years. It was also shown that strong UV radiation emitted by nearby massive stars can heat a

Mohammed Daoud, Ahmed Jellal

The Landau problem on the flag manifold ${\bf F}_2 = SU(3)/U(1)\times U(1)$ is analyzed from an algebraic point of view. The involved magnetic background is induced by two U(1) abelian connections. In quantizing the theory, we show that the wavefunctions, of a non-relativistic particle living on ${\bf F}_2$, are the SU(3) Wigner ${\cal D}$-functions satisfyi

Jamila Douari

We discuss the duality of intersecting D1-D5 branes in the low energy effective theory in the presence of electric field. This duality is found to be unbroken. We also deal with the solutions corresponding to two and three excited scalars in the D3-brane theory in the absence and the presence of an electric field. The solutions are given as a spike which is

Alakabha Datta, Ken Kiers, David London, Patrick J. O'Donnell

We re-examine CP violation in the Delta S = 0 decays tau -> N pi nu_tau (N=2,3,4). We assume that the new physics (NP) is a charged Higgs. We show that there is no NP contribution to tau -> pi pi nu_tau, which means that no CP violation is expected in this decay. On the other hand, NP can contribute to tau -> N pi nu_tau (N=3,4). These are dominated by the i

James E. Lidsey, David Seery

We study brane inflation scenarios in a warped throat geometry and show that there exists a consistency condition between the non-Gaussianity of the curvature perturbation and the amplitude and scale-dependence of the primordial gravitational waves. This condition is independent of the warping of the throat and the form of the inflaton potential. We find tha

Ol'ga V. Sipacheva

It is proved that, in certain subgroups of direct products of countable groups, the property of being an unconditionally closed set coincides with that of being an algebraic set. In particular, these properties coincide in all Abelian groups.

Francesco Bonsante, Kirill Krasnov, Jean-Marc Schlenker

We prove an "Earthquake Theorem" for hyperbolic metrics with geodesic boundary on a compact surfaces $S$ with boundary: given two hyperbolic metrics with geodesic boundary on a surface with $k$ boundary components, there are $2^k$ right earthquakes transforming the first in the second. An alternative formulation arises by introducing the enhanced Tei

Shoichi Sasaki, Takeshi Yamazaki

We discuss formation of an S-wave bound-state in finite volume on the basis of Lüscher's phase-shift formula.It is found that although a bound-state pole condition is fulfilled only in the infinite volume limit, its modification by the finite size corrections is exponentially suppressed by the spatial extent $L$ in a finite box $L^3$. We also confirm tha

S. Ono, Seiki Komiya, Yoichi Ando

By measuring the Hall coefficient R_H up to 1000 K in La_2CuO_4, Pr_{1.3}La_{0.7}CuO_4, and La_{2-x}Sr_xCuO_4 (LSCO), we found that the temperature (T) dependence of R_H in LSCO for x = 0 - 0.05 at high temperature undoubtedly signifies a gap over which the charge carriers are thermally activated, which in turn indicates that in lightly-doped cuprates strong

Lars Birkedal, Noah Torp-Smith, Hongseok Yang

We show how to give a coherent semantics to programs that are well-specified in a version of separation logic for a language with higher types: idealized algol extended with heaps (but with immutable stack variables). In particular, we provide simple sound rules for deriving higher-order frame rules, allowing for local reasoning.

Urs Langenegger

We present a Monte Carlo simulation study of measuring the rare leptonic decay Bs->mu+mu- with the CMS experiment at the LHC. The study is based on a full detector simulation for signal and background events. We discuss the high-level trigger algorithm and the offline event selection.

Stéphane Le Roux, Martin Ziegler

The empty set of course contains no computable point. On the other hand, surprising results due to Zaslavskii, Tseitin, Kreisel, and Lacombe assert the existence of NON-empty co-r.e. closed sets devoid of computable points: sets which are `large' in the sense of positive Lebesgue measure. We observe that a certain size is in fact necessary: every non-emp

David Callan

We count permutations avoiding a nonconsecutive instance of a two- or three-letter pattern, that is, the pattern may occur but only as consecutive entries in the permutation. Two-letter patterns give rise to the Fibonacci numbers. The counting sequences for the two representative three-letter patterns, 321 and 132, have respective generating functions (1+x^2

M. Klasen, G. Pignol

We derive Feynman rules for the interactions of a single gravitino with (s)quarks and gluons/gluinos from an effective supergravity Lagrangian in non-derivative form and use them to calculate the hadroproduction cross sections and decay widths of single gravitinos. We confirm the results obtained previously with a derivative Lagrangian as well as those obtai

Leonid Kontorovich

We derive sufficient conditions for a family $(X^n,ρ_n,P_n)$ of metric probability spaces to have the measure concentration property. Specifically, if the sequence $\{P_n\}$ of probability measures satisfies a strong mixing condition (which we call $η$-mixing) and the sequence of metrics $\{ρ_n\}$ is what we call $Ψ$-dominated, we show that $(X^n,ρ_n,P_n)$ i

The Belle Collaboration, K. Abe

We report on a high statistics measurement of the cross section of the process gamma gamma to pi^+ pi^- in the center-of-mass energy range 0.8 GeV/c^2 < W < 1.5 GeV/c^2 with 85.9 fb^-1 of data collected at sqrt(s)=10.58 GeV and 10.52 GeV with the Belle detector. A clear signal for the f_0 lr 980 resonance is observed. From a fit to the mass spectrum, the res

Jacques Arnaud, Laurent Chusseau, Fabrice Philippe

When light originating from a laser diode driven by non-fluctuating electrical currents is incident on a photo-detector, the photo-current does not fluctuate much. Precisely, this means that the variance of the number of photo-electrons counted over a large time interval is much smaller that the average number of photo-electrons. At non-zero Fourier frequenc

J. A. D. Appleby, G. Berkolaiko, A. Rodkina

We consider stochastic difference equation x_{n+1} = x_n (1 - h f(x_n) + \sqrt{h} g(x_n) ξ_{n+1}), where functions f and g are nonlinear and bounded, random variables ξ_i are independent and h>0 is a nonrandom parameter. We establish results on asymptotic stability and instability of the trivial solution x_n=0. We also show, that for some natural choices of

S. Mendoza, Y. M. Rosas-Guevara

We investigate in detail two physical properties of the metric f(R) theory developed by Sobouti (2007). We first look for the possibility of producing gravitational waves that travel at the speed of light. We then check the possibility of producing extra bending in the lenses produced by the theory. We do this by using standard weak field approximations to t

Christian Buth

The Hartree-Fock equations are modified to directly yield Wannier functions following a proposal of Shukla et al. [Chem. Phys. Lett. 262, 213-218 (1996)]. This approach circumvents the a posteriori application of the Wannier transformation to Bloch functions. I give a novel and rigorous derivation of the relevant equations by introducing an orthogonalizing p

Tobias Ambjornsson, Michael A. Lomholt, Per Lyngs Hansen

We investigate the effect on biomembrane mechanical properties due to the presence an external potential for a non-conductive non-compressible membrane surrounded by different electrolytes. By solving the Debye-Huckel and Laplace equations for the electrostatic potential and using the relevant stress-tensor we find: in (1.) the small screening length limit,

Qing-Guo Huang

Three-year data of WMAP implies not only a negative running of the spectral index with large absolute value, but also a large positive running of running of the spectral index with order of the magnitude $10^{-2}$. We calculate the running of running in usual inflation model and noncommutative inflation model. A large tensor-scalar ratio $r\geq 1.23$ is need

S. Gaertner, C. Kurtsiefer, M. Bourennane, H. Weinfurter

Secret sharing is a multiparty cryptographic task in which some secret information is splitted into several pieces which are distributed among the participants such that only an authorized set of participants can reconstruct the original secret. Similar to quantum key distribution, in quantum secret sharing, the secrecy of the shared information relies not o

Mete Atature, Jan Dreiser, Antonio Badolato, Atac Imamoglu

Ability to read-out the state of a single confined spin lies at the heart of solid-state quantum information processing. While all-optical spin measurements using Faraday rotation has been successfully implemented in ensembles of semiconductor spins, read-out of a single semiconductor spin has only been achieved using transport measurements based on spin-cha

C. Mora, H. Briegel, B. Kraus

Kolmogorov complexity is a measure of the information contained in a binary string. We investigate here the notion of quantum Kolmogorov complexity, a measure of the information required to describe a quantum state. We show that for any definition of quantum Kolmogorov complexity measuring the number of classical bits required to describe a pure quantum stat

P. Facchi, G. Florio, S. Pascazio

A method is proposed to characterize and quantify multipartite entanglement in terms of the probability density function of bipartite entanglement over all possible balanced bipartitions of an ensemble of qubits. The method is tested on a class of random pure states.

Plamen G. Petrov, Daniel Oblak, Carlos L. Garrido Alzar, Niels Kjaergaard

A method for non-destructive characterization of a dipole trapped atomic sample is presented. It relies on a measurement of the phase-shift imposed by cold atoms on an optical pulse that propagates through a free space Mach-Zehnder interferometer. Using this technique we are able to determine, with very good accuracy, relevant trap parameters such as the ato

Shengchao Ding, Zhi Jin, Qing Yang

Quantum oracles play key roles in the studies of quantum computation and quantum information. But implementing quantum oracles efficiently with universal quantum gates is a hard work. Motivated by genetic programming, this paper proposes a novel approach to evolve quantum oracles with a hybrid quantum-inspired evolutionary algorithm. The approach codes quant

I. Klapper, P. Gilbert, B. P. Ayati, J. Dockery

It has been known for many years that small fractions of persister cells resist killing in many bacterial colony-antimicrobial confrontations. These persisters are not believed to be mutants. Rather it has been hypothesized that they are phenotypic variants. Current models allow cells to switch in and out of the persister phenotype. Here we suggest a differe

Tom Michoel, Yves Van de Peer

An inhomogeneous helicoidal nearest-neighbor model with continuous degrees of freedom is shown to predict the same DNA melting properties as traditional long-range Ising models, for free DNA molecules in solution, as well as superhelically stressed DNA with a fixed linking number constraint. Without loss of accuracy, the continuous degrees of freedom can be

Andrei Faraon, Edo Waks, Dirk Englund, Ilya Fushman

Coupling of photonic crystal (PC) linear three-hole defect cavities (L3) to PC waveguides is theoretically and experimentally investigated. The systems are designed to increase the overlap between the evanescent cavity field and the waveguide mode, and to operate in the linear dispersion region of the waveguide. Our simulations indicate increased coupling wh

J. -P. Onnela, J. Saramaki, J. Hyvonen, G. Szabo

Electronic databases, from phone to emails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure

Baruch Meerson, Pavel V. Sasorov, Arkady Vilenkin

We investigate the dynamics of relaxation, by surface tension, of a family of curved interfaces between an inviscid and viscous fluids in a Hele-Shaw cell. At t=0 the interface is assumed to be of the form |y|=A x^m, where A>0, m \geq 0, and x>0. The case of 0<m<1 corresponds to a smooth shape, m>1 corresponds to a cusp, whereas m=1 corresponds to a wedge. T

Dong Li, Yakov Sinai

We consider complex-valued solutions of the three-dimensional Navier-Stokes system without external forcing on $R^3$. We show that there exists an open set in the space of 10-parameter families of initial conditions such that for each family from this set there are values of parameters for which the solution develops blow up in finite time.

Randolf Pohl, Herbert Daniel, F. Joachim Hartmann, Peter Hauser

The kinetic energy distribution of ground state muonic hydrogen atoms mu-p(1S) is determined from time-of-flight spectra measured at 4, 16, and 64 hPa H2 room-temperature gas. A 0.9 keV-component is discovered and attributed to radiationless deexcitation of long-lived mu-p(2S) atoms in collisions with H2 molecules. The analysis reveals a relative population

Gordon Chalmers

A configuration of light pulses is generated, together with emitters and receptors, that allows computing. The computing is extraordinarily high in number of flops per second, exceeding the capability of a quantum computer for a given size and coherence region. The emitters and receptors are based on the quantum diode, which can emit and detect individual ph

T. Zanon-Willette, A. D. Ludlow, S. Blatt, M. M. Boyd

We propose a combination of Electromagnetically Induced Transparency (EIT)/Raman and pulsed spectroscopy techniques to accurately cancel frequency shifts arising from EIT fields in forbidden optical lattice clock transitions of alkaline earth atoms. Time-separated laser pulses are designed to trap atoms in coherent superpositions while eliminating off-resona

Shin-ichi Inage

The Schrodinger equation based on the de Broglie wave is the most fundamental equation of the quantum mechanics. There can be no doubt about it&#39;s prediction validity. However, the probabilistic interpretation on the quantum mechanics has insoluble semantic interpretations like reduction of wave packet on observations of physical values. Especially, it is

Martin M. Boyd, Tanya Zelevinsky, Andrew D. Ludlow, Seth M. Foreman

Highest resolution laser spectroscopy has generally been limited to single trapped ion systems due to rapid decoherence which plagues neutral atom ensembles. Here, precision spectroscopy of ultracold neutral atoms confined in a trapping potential shows superior optical coherence without any deleterious effects from motional degrees of freedom, revealing opti

Lie-Wen Chen, Che Ming Ko, Bao-An Li

Recent analysis of the isospin diffusion data from heavy-ion collisions based on an isospin- and momentum-dependent transport model with in-medium nucleon-nucleon cross sections has led to the extraction of a value of $L=88\pm 25$ MeV for the slope of the nuclear symmetry energy at saturation density. This imposes stringent constraints on both the parameters

Roelof Bijker

I discuss a two-component model of nucleon form factors in which the external photon couples both to an intrinsic three-quark structure and to a meson cloud via vector-meson dominance, and present a simultaneous analysis of the electromagnetic form factors of the nucleon in the space- and time-like regions as well as their strangeness content.

SNO Collaboration

This article provides the complete description of results from the Phase I data set of the Sudbury Neutrino Observatory (SNO). The Phase I data set is based on a 0.65 kt-year exposure of heavy water to the solar $^8$B neutrino flux. Included here are details of the SNO physics and detector model, evaluations of systematic uncertainties, and estimates of back

Vladimir I. Inozemtsev, Natalia G. Inozemtseva

The simplified models of interaction of charged matter with resonance modes of radiation generalizing the well-known Jaynes-Cummings and Dicke models are considered. It is found that these new models are integrable for arbitrary numbers of dipole sources and resonance modes of the radiation field. The problem of explicit diagonalisation of corresponding Hami

Nick Crawford

We study aspects of the thermodynamics of quantum versions of spin glasses. By means of the Lie-Trotter formula for exponential sums of operators, we adapt methods used to analyze classical spin glass models to answer analogous questions about quantum models.

W. De Roeck, C. Maes, K. Netocny

Before the thermodynamic limit, macroscopic averages need not commute for a quantum system. As a consequence, aspects of macroscopic fluctuations or of constrained equilibrium require a careful analysis, when dealing with several observables. We propose an implementation of ideas that go back to John von Neumann&#39;s writing about the macroscopic measuremen

Brian J. Day, Stephen Lack

For a small category K enriched over a suitable monoidal category V, the free completion of K under colimits is the presheaf category [K*,V]. If K is large, its free completion under colimits is the V-category PK of small presheaves on K, where a presheaf is small if it is a left Kan extension of some presheaf with small domain. We study the existence of lim

Zoltan Szabo, Andras Lorincz

Here, we address the problem of Independent Subspace Analysis (ISA). We develop a technique that (i) builds upon joint decorrelation for a set of functions, (ii) can be related to kernel based techniques, (iii) can be interpreted as a self-adjusting, self-grouping neural network solution, (iv) can be used both for real and for complex problems, and (v) can b

Manuel Breuning

We study determinant functors which are defined on a triangulated category and take values in a Picard category. The two main results are the existence of a universal determinant functor for every small triangulated category, and a comparison theorem for determinant functors on a triangulated category with a non-degenerate bounded t-structure and determinant

Alexander I. Bobenko, Yuri B. Suris

We give an elaborated treatment of discrete isothermic surfaces and their analogs in different geometries (projective, Möbius, Laguerre, Lie). We find the core of the theory to be a novel projective characterization of discrete isothermic nets as Moutard nets. The latter belong to projective geometry and are nets with planar faces defined through a five-poin

Sergey Khoroshkin, Stanislav Pakuliak

We give a precise expression for the universal weight function of the quantum affine algebra $U_q(\hat{sl}_3)$. The calculations use the technique of projecting products of Drinfeld currents on the intersections of Borel subalgebras.

Lajos Soukup

Nagata conjectured that every $M$-space is homeomorphic to a closed subspace of the product of a countably compact space and a metric space. This conjecture was refuted by Burke and van Douwen, and A. Kato, independently. However, we can show that there is a c.c.c. poset $P$ of size $2^ω$ such that in $V^P$ Nagata&#39;s conjecture holds for each first counta

Marius Ghergu, Vicentiu Radulescu

We are concerned with singular elliptic equations of the form $-Δu= p(x)(g(u)+ f(u)+|\nabla u|^a)$ in $\RR^N$ ($N\geq 3$), where $p$ is a positive weight and $0< a <1$. Under the hypothesis that $f$ is a nondecreasing function with sublinear growth and $g$ is decreasing and unbounded around the origin, we establish the existence of a ground state solution va

Kanetomo Sato

In this paper, we define, for arithmetic schemes with semistable reduction, $p$-adic objects playing the roles of Tate twists in étale topology, and establish their fundamental properties.

T. P. McDonough, C. A. Pallikaros

This paper has been withdrawn by the authors due to essential errors in Theorem 5.6.

Roman Bezrukavnikov, Ivan Mirković, Dmitriy Rumynin

We observe that on the level of derived categories, representations of the Lie algebra of a semisimple algebraic group over a field of characteristic $p> h$ (where $h$ is the Coxeter number), with a given (generalized) central character are the same as the coherent sheaves on (generalized) Springer fibers. The first step is to observe that the derived functo

J. W. Moffat

The action for gravity and the standard model includes, as well as the positive energy fermion and boson fields, negative energy fields. The Hamiltonian for the action leads through a positive and negative energy symmetry of the vacuum to a cancellation of the zero-point vacuum energy and a vanishing cosmological constant in the presence of a gravitational f

V. A. Franke, S. A. Paston, E. V. Prokhvatilov

A possibility of semiphenomenological description of vacuum effects in QCD quantized on the Light Front (LF) is discussed. A modification of the canonical LF Hamiltonian for QCD is proposed, basing on the detailed study of the exact description of vacuum condensate in QED(1+1) that uses correct form of LF Hamiltonian.

V. A. Karmanov, J. Carbonell, M. Mangin-Brinet

Some results obtained by a new method for solving the Bethe-Salpeter equation are presented. The method is valid for any kernel given by irreducible Feynman graphs. The Bethe-Salpeter amplitude, both in Minkowski and in Euclidean spaces, and the binding energy for ladder + cross-ladder kernel are found. We calculate also the corresponding electromagnetic for

Luca Griguolo, Domenico Seminara, Richard J. Szabo, Alessandro Tanzini

We study the relationship between instanton counting in N=4 Yang-Mills theory on a generic four-dimensional toric orbifold and the semi-classical expansion of q-deformed Yang-Mills theory on the blowups of the minimal resolution of the orbifold singularity, with an eye to clarifying the recent proposal of using two-dimensional gauge theories to count microst

Ying-Qiu Gu

In this paper, we propose a new approach to the relativistic quantum mechanics for many-body, which is a self-consistent system constructed by juxtaposed but mutually coupled nonlinear Dirac&#39;s equations. The classical approximation of this approach provides the exact Newtonian dynamics for many-body, and the nonrelativistic approximation gives the comple

N. Hatcher, A. Restuccia, J. Stephany

We consider the action of the D=11 supermembrane wrapping a compactified sector of the target space in such a way that a non trivial central charge in the SUSY algebra is induced. We show that the dynamics of the center of mass corresponds to a superparticle in D=9 with additional fermionic terms associated to the central charges . We perform the covariant q

S. A. Yost, B. F. L. Ward

We discuss techniques for obtaining a numerically-stable evaluation of the fully differential cross section for the virtual photon correction to single hard photon bremsstrahlung in two different computational schemes. We also compare the role of finite mass corrections in these schemes.

Dmitri Diakonov

The experimental status of the pentaquark searches is briefly reviewed. Recent null results by the CLAS collaboration are commented, and new strong evidence of a very narrow Theta+ resonance by the DIANA collaboration is presented. On the theory side, I revisit the argument against the existence of the pentaquark -- that of Callan and Klebanov -- and show th

Guido Altarelli, Ferruccio Feruglio, Yin Lin

We show that the A4 discrete symmetry that naturally leads to tri-bimaximal neutrino mixing can be simply obtained as a result of an orbifolding starting from a model in 6 dimensions. This particular orbifolding has four fixed points where 4 dimensional branes are located and the tetrahedral symmetry of A4 connects these branes. In this approach A4 appears a

E. Megias, E. Ruiz Arriola, L. L. Salcedo

We address a possible relation between the expectation value of the Polyakov loop in pure gluodynamics and full QCD based on Polyakov Chiral Quark Models where constituent quarks and the Polyakov loop are coupled in a minimal way. To this end we use a center symmetry breaking Gaussian model for the Polyakov loop distribution which accurately reproduces gluod

Anjishnu Sarkar, Urjit Yajnik

We consider a supersymmetric SO(10) model which remains renormalisable upto Planck scale. The cosmology of such a model passes through a Left-Right symmetric phase. Potential problems associated with domain walls can be evaded if parity breaking is induced by soft terms when supersymmetry breaks in the hidden sector. The smallness of this breaking permits a

A. E. Radzhabov, M. K. Volkov

The decay width of the process eta -> pi^0 gamma gamma is calculated in the framework of the Nambu-Jona-Lasinio model. The momentum dependence of quark loops is taken into account. Three types of diagrams are considered: quark box, scalar(a0) and vector(rho, omega) pole diagrams. The obtained estimations are in satisfactory agreement with recent experimental

W. Grimus

Some models for the lepton sector, based on seesaw extensions of the Standard Model, are discussed in which the mu-tau interchange symmetry is realized in various ways. The symmetries defining such models and their characteristic predictions for lepton mixing are presented.

Marcela Carena, Jay Hubisz, Maxim Perelstein, Patrice Verdier

Little Higgs models with T Parity contain new vector-like fermions, the T-odd quarks or &#34;T-quarks&#34;, which can be produced at hadron colliders with a QCD-strength cross section. Events with two acoplanar jets and large missing transverse energy provide a simple signature of T-quark production. We show that searches for this signature with the Tevatron

M. Osipenko

We discuss the role of nucleon and its excited state poles in the twist expansion of the nucleon structure function moments. We find that the nucleon pole contribution was overestimated in previous analyses by a factor of two. Inclusion of this missing factor makes the duality appear for all moments at least down to Q2=1 GeV2. For resonance poles the time re

J. B. Bronzan

We study pure SU(3) gauge theory on a large lattice, using Schrodinger&#39;s equation. Our approximate solution uses a basis of roughly 1000 states. Gauge invariance is recovered when the color content of the ground state is extrapolated to zero. We are able to identify the gauge invariant excitations that remain when the extrapolation is performed. In the w

P. Cea, L. Cosmai, M. D&#39;Elia, A. Papa

The method of analytical continuation from imaginary to real chemical potential is tested in 2-color QCD. In comparison to previous studies in the same theory, an exact updating algorithm is used and simulations are performed closer to the thermodynamic limit. It is shown that the method considerably improves if suitable functions are used to interpolate dat

V. Weinberg, E. -M. Ilgenfritz, K. Koller, Y. Koma

We summarize different uses of the eigenmodes of the Neuberger overlap operator for the analysis of the QCD vacuum, here applied to quenched configurations simulated by means of the Luescher-Weisz action. We describe the localization and chiral properties of the lowest modes. The overlap-based topological charge density (with and without UV-filtering) is com

F. De Soto, J. Carbonell, C. Roiesnel, Ph. Boucaud

The extraction of scattering parameters from Euclidean simulations of a Yukawa model in a finite volume with periodic boundary conditions is analyzed both in non relativistic quantum mechanics and in quantum field theory.

Sinya Aoki, Oliver Bar

We perform a Wilson Chiral Perturbation Theory (WChPT) analysis of quenched twisted mass lattice data. The data were generated by two independent groups with three different choices for the critical mass. For one choice, the so-called pion mass definition, one observes a strong curvature for small quark masses in various mesonic observables (&#39;&#39;bendin

F. De Soto, J. Carbonell, C. Roiesnel, Ph. Boucaud

We present first results of the solutions of the Yukawa model as a Quantum Field Theory (QFT) solved non perturbatively with the help of lattice calculations. In particular we will focus on the possibility of binding two nucleons in the QFT, compared to the non relativistic result.

Johan Bijnens, Karim Ghorbani

We have computed the quark anti-quark expectation value in finite volume at two loop in chiral perturbation theory and compare it with a formula obtained in analogy to the Luscher formula for pion mass in finite volume. We observe that due to the small finite size correction at two loop it is not possible to obtain conclusions on the accuracy of the extended

Shoichi Sasaki, Takeshi Yamazaki

We present results of an exploratory study of flavor SU(3) breaking effects in hyperon beta decays using domain wall fermions. From phenomenological point of view, the significance of this subject is twofold: (1) to extract the element $V_{us}$ of the Cabibbo-Kabayashi-Maskawa mixing matrix from the $ΔS=1$ decay process, and (2) to provide vital information

Thomas Kluge

A review is given on recent alpha(s) determinations from the H1 and ZEUS Collaborations. These are based on measurements of jet cross sections, event shape variables, as well as on the observed scaling violation of the structure function F_2. A HERA average on alpha(s)(m_Z) is presented, in comparison with world mean values.

Abel Camacho

In the present work the thermodynamical properties of bosonic and fermionic gases are analyzed under the condition that a modified dispersion relation is present. This last condition implies a breakdown of Lorentz symmetry. The implications upon the condensation temperature will be studied, as well, as upon other thermodynamical variables such as specific he