July 2004 arXiv papers — page 11

Piyabut Burikham

We calculate the tree-level open-string amplitudes for the scattering of four massless particles with diphoton final states. These amplitudes are required to reproduce those of standard model at the tree level in the low energy limit. After low energy stringy corrections, we found that they have similar form to the same processes induced by exchange of the K

Yong-Seon Song

The cosmic acceleration was discovered in one of the brane-based models. We are interested in discriminating this model from the dark energy by tomographic cosmic shear. Growth factors are different in the two models when one adjusts parameters to get nearly identical H(z). The two models could be distinguished with independent determinations of both geometr

G. Duchene, J. Bouvier, S. Bontemps, P. Andre

(Abridged) We performed a deep infrared imaging survey of 63 embedded young stellar objects (YSOs) located in the Taurus and Ophiuchus clouds to search for companions. The sample includes Class I and flat infrared spectrum protostellar objects. We find 17 companions physically bound to 15 YSOs with angular separations in the range 0.8-10" (110-1400 AU) a

Gernot Schaller, Michael Meyer-Hermann

We study multicellular tumor spheroids by introducing a new three-dimensional agent-based Voronoi/Delaunay hybrid model. In this model, the cell shape varies from spherical in thin solution to convex polyhedral in dense tissues. The next neighbors of the cells are provided by a weighted Delaunay triangulation with in average linear computational complexity.

Ido Adam, Yaron Oz

We consider four-dimensional N=1 supersymmetric gauge theories in a supergravity background. We use generalized Konishi anomaly equations and R-symmetry anomaly to compute the exact perturbative and non-perturbative gravitational F-terms. We study two types of theories: The first model breaks supersymmetry dynamically, and the second is based on a $G_2$ gaug

Christoph Mayer, Thomas Mohaupt

We construct BPS domain wall solutions of the effective action of type-IIA string theory compactified on a half-flat six-manifold. The flow equations for the vector and hypermultiplet scalars are shown to be equivalent to Hitchin's flow equations, implying that our domain walls can be lifted to solutions of ten-dimensional type-IIA supergravity. They tak

M. Hirsch, J. C. Romao, J. W. F. Valle, A. Villanova del Moral

The Higgs boson may decay mainly to an invisible mode characterized by missing energy, instead of the Standard Model channels. This is a generic feature of many models where neutrino masses arise from the spontaneous breaking of ungauged lepton number at relatively low scales, such as spontaneously broken R-parity models. Taking these models as framework, we

Michal Chodorowski

We derive the prediction of the standard model of superluminal radio sources for the apparent transverse velocity of a radio source located at redshift z. The apparent velocity of the source is reduced by a factor of 1 + z compared to that of a similar nearby source. The cause of this reduction is recession of the distant source due to the expansion of the u

B. Machet, V. A. Novikov, M. I. Vysotsky

Quasi-degenerate binary systems of neutral mesons of the kaon type are investigated in Quantum Field Theory (QFT). General constraints cast by analyticity and discrete symmetries P, C, CP, TCP on the propagator (and on its spectral function) are deduced. Its poles are the physical masses; this unambiguously defines the propagating eigenstates. It is diagonal

Paolo Piazza, Thomas Schick

Let G be a finitely generated discrete group. In this paper we establish vanishing results for rho-invariants associated to (i) the spin-Dirac operator of a spin manifold with positive scalar curvature (ii) the signature operator of the disjoint union of a pair of homotopy equivalent oriented manifolds with fundamental group G. The invariants we consider are

David Kerr, Hanfeng Li

We introduce a version of Voiculescu-Brown approximation entropy for isometric automorphisms of Banach spaces and develop within this framework the connection between dynamics and the local theory of Banach spaces discovered by Glasner and Weiss. Our fundamental result concerning this contractive approximation entropy, or CA entropy, characterizes the occurr

F. Alexander Bais

Magnetic monopoles form an inspiring chapter of theoretical physics, covering a variety of surprising subjects. We review their role in non-abelian gauge theories. An expose of quite exquisite physics derived from a hypothetical particle species, because the fact remains that in spite of ever more tempting arguments from theory, monopoles have never reared t

F. R. Klinkhamer, G. E. Volovik

We discuss the quantum phase transition that separates a vacuum state with fully-gapped fermion spectrum from a vacuum state with topologically-protected Fermi points (gap nodes). In the context of condensed-matter physics, such a quantum phase transition with Fermi point splitting may occur for a system of ultracold fermionic atoms in the region of the BEC-

Sylvain Barré, Abdelghani Zeghib

We consider spaces for which there is a notion of harmonicity for complex valued functions defined on them. For instance, this is the case of Riemannian manifolds on one hand, and (metric) graphs on the other hand. We observe that it is then possible to define an "amazing" notion of holomorphic functions on them, and show how rigid it is in some case

Q. P. Liu, Xing-Biao Hu, Meng-Xia Zhang

A proper bilinear form is proposed for the N=1 supersymmetric modified Korteweg-de Vries equation. The bilinear Bäcklund transformation of this system is constructed. As applications, some solutions are presented for it.

B. Desplanques

Form factors of a simple system have been calculated in various forms of relativistic quantum mechanics, using a single-particle current. Their comparison has shown large discrepancies. The comparison is extended here to instant- and front-form calculations in unusual momentum configurations as well as to a point-form approach inspired from the Dirac's one (

H. D. Yang, J. -Y. Lin, C. P. Sun, Y. C. Kang

Comprehensive low-temperature specific heat data C(T,H) of Na_0.35CoO2-1.3H_2O with temperature T down to 0.6 K and the magnetic field H up to 8 T are presented. For the normal state, the values of gamma_n=13.94 mJ/mol K2, and Debye temperature 362 K are reported. At zero field, a very sharp superconducting anomaly was observed at Tc=4.5 K with DeltaC/gamma_

Th. Koschny, L. Schweitzer

We investigate the fate of the quantum Hall extended states within a continuum model with spatially correlated disorder potentials. The model can be projected onto a couple of the lowest Landau bands. Levitation of the $n=0$ critical states is observed if at least the two lowest Landau bands are considered. The dependence on the magnetic length $l_B=(\hbar/(

A. Achucarro, J. Urrestilla

We derive the Bogomol'nyi equations for supersymmetric Abelian F-term cosmic strings in four-dimensional flat space and show that, contrary to recent statements in the literature, they are BPS states in the Bogomol'nyi limit, but the partial breaking of supersymmetry is from N=2. The second supersymmetry is not obvious in the N=1 formalism, so we giv

D. Porquet, J. N. Reeves, P. Uttley, T. J. Turner

We present a spectral analysis of the Seyfert 1.8 ESO 113-G010 observed with XMM-Newton for 4 ks. The spectrum shows a soft excess below 0.7 keV and more interestingly a narrow emission Gaussian line at 5.4 keV (in its rest-frame), most probably originating from a redshifted iron Kalpha line. No significant line at or above 6.4 keV is found contrary to other

Toyohiro Tsurumaru

Quantum bit-string commitment[A.Kent, Phys.Rev.Lett., 90, 237901 (2003)] or QBSC is a variant of bit commitment (BC). In this paper, we propose a new QBSC protocol that can be implemented using currently available technology, and prove its security under the same security criteria as discussed by Kent. QBSC is a generalization of BC, but has slightly weaker

Izumi Hachisu, Mariko Kato

We present a new interpretation of long premaximum halts of nova outbursts. For V723 Cas (Nova Cas 1995) and V463 Sct (Nova Sct 2000), we have reproduced light curves, excluding the brightness maxima, starting from the long premaximum halt through the late decay phase of the outbursts using a steady-state optically thick wind model. When the hydrogen-rich en

Y. Hama, T. Kodama, O. Socolowski

A survey is given on the applications of hydrodynamic model of nucleus-nucleus collisons, focusing especially on i) the resolution of hydrodynamic equations for arbitrary configurations, by using the smoothed-particle hydrodynamic approach; ii) effects of the event-by-event fluctuation of the initial conditions on the observables; iii) decoupling criteria; i

Giuseppe Pareschi, Mihnea Popa

We prove and conjecture results which show that Castelnuovo theory in projective space has a close analogue for abelian varieties. This is related to the geometric Schottky problem: our main result is that a principally polarized abelian variety satisfies a precise version of the Castelnuovo Lemma if and only if it is a Jacobian. This result has a surprising

Nandor Simanyi

We consider the system of $N$ ($\ge2$) elastically colliding hard balls of masses $m_1,...,m_N$ and radius $r$ in the flat unit torus $\Bbb T^ν$, $ν\ge2$. In the case $ν=2$ we prove (the full hyperbolicity and) the ergodicity of such systems for every selection $(m_1,...,m_N;r)$ of the external geometric parameters, without exceptional values. In higher dime

Rasulkhozha S. Sharafiddinov

At the availability of a nonzero mass, the same neutrino regardless of whether it refers to Dirac or Majorana fermions, must possess simultaneously each of the anapole and electric dipole moments. Their interaction with the field of emission can also lead to the elastic scattering of the longitudinal polarized neutrinos on a spinless nucleus. Using the cross

Brian C. Tiburzi, Andre Walker-Loud

The masses of the spin-3/2 baryons are calculated to next-to-next-to-leading order in heavy baryon chiral perturbation theory and partially quenched heavy baryon chiral perturbation theory. The calculation is performed for three light flavors in the isospin limit. These results are necessary for extrapolating QCD and partially quenched QCD lattice calculatio

Masatoshi Imanishi, Kouichiro Nakanishi, Nario Kuno, Kotaro Kohno

We present near-infrared and millimeter investigations of the nucleus of the infrared luminous galaxy NGC 4418, which previous observations suggest possesses a powerful buried AGN. We found the following main results: (1) The infrared K-band spectrum shows CO absorption features at 2.3-2.4 micron owing to stars and very strong H2 emission lines. The luminosi

I. V. Dobrovolska, R. S. Tutik

The explicit semiclassical treatment of the logarithmic perturbation theory for the bound-state problem for the spherical anharmonic oscillator is developed. Based upon the $\hbar$-expansions and suitable quantization conditions a new procedure for deriving perturbation expansions is offered. Avoiding disadvantages of the standard approach, new handy recursi

R. Garcia-Patron, J. Fiurasek, N. J. Cerf

We provide a detailed analysis of the recently proposed setup for a loophole-free test of Bell inequality using conditionally generated non-Gaussian states of light and balanced homodyning. In the proposed scheme, a two-mode squeezed vacuum state is de-gaussified by subtracting a single photon from each mode with the use of an unbalanced beam splitter and a

Yu. M. Golubev, T. Yu. Golubeva, Yu. V. Rostovtsev, M. O. Scully

We have shown that quantum interference in a driven quasi-degenerate two-level atomic system can be controlled by an externally applied magnetic field. We demonstrate that the mechanism of optical control is based on quantum interference, which allows one to implement both electromagnetically induced transparency and electromagnetically induced absorption in

Florian Hulpke, Dagmar Bruss

We propose an algorithm which proves a given bipartite quantum state to be separable in a finite number of steps. Our approach is based on the search for a decomposition via a countable subset of product states, which is dense within all product states. Performing our algorithm simultaneously with the algorithm by Doherty, Parrilo and Spedalieri (which prove

N. Khaneja, J. S. Li, C. Kehlet, B. Luy

Many applications of magnetic resonance are limited by rapid loss of spin coherence caused by large transverse relaxation rates. In nuclear magnetic resonance (NMR) of large proteins, increased relaxation losses lead to poor sensitivity of experiments and increased measurement time. In this paper we develop broadband relaxation optimized pulse sequences (BB-

Shi-Liang Zhu, Paolo Zanardi

We analyze a scheme for quantum computation where quantum gates can be continuously changed from standard dynamic gates to purely geometric ones. These gates are enacted by controlling a set of parameters that are subject to unwanted stochastic fluctuations. This kind of noise results in a departure from the ideal case that can be quantified by a gate fideli

F. Sciarrino, C. Sias, M. Ricci, F. De Martini

Optimal quantum machines can be implemented by linear projective operations. In the present work a general qubit symmetrization theory is presented by investigating the close links to the qubit purification process and to the programmable teleportation of any generic optimal anti-unitary map. In addition, the contextual realization of the N ->M cloning map a

Constantin V. Usenko, Vladyslav C. Usenko

This work is the development and analysis of the recently proposed quantum cryptographic protocol, based on the use of the two-mode coherently correlated states. The protocol is supplied with the cyrptographic control procedures. The channel error properties and stability against eavesdropping are examined. State detection features are proposed.

I. E. Mazets

We investigate the problem of propagation of three-component resonant light pulses with adiabatically varying amplitudes through a medium consisting of atoms with the tripod level configuration. By means of both analytic and numerical methods we found the two modes of shape-preserving pulse propagation. The pulse propagation velocity is found to be either eq

Jinfeng Zhang, Rong Chen, Jie Liang

An effective potential function is critical for protein structure prediction and folding simulation. For simplified models of proteins where coordinates of only $C_α$ atoms need to be specified, an accurate potential function is important. Such a simplified model is essential for efficient search of conformational space. In this work, we present a formulatio

M. Ball, N. Ghodbane, M. Janssen, P. Wienemann

Within the international studies of a high energy linear electron positron collider, several groups are developing and testing prototypes for a Linear Collider TPC. This detector is planned to be used as a central part in the tracking system of a detector at such a machine. In this note we describe a DAQ system, which has been developed for the use in tests

M. Rapacioli, F. Calvo, F. Spiegelman, C. Joblin

Clusters of polycyclic aromatic hydrocarbon (PAH) molecules are modelled using explicit all-atom potentials using a rigid body approximation. The PAH's considered range from pyrene (C10H8) to circumcoronene (C54H18), and clusters containing between 2 and 32 molecules are investigated. In addition to the usual repulsion-dispersion interactions, electrosta

Zikri M. Yusof, Manoel E. Conde, Wei Gai

We present a clear signature of the Schottky effect in a RF photoinjector using photons with energy lower than the Mg cathode work function. This signature is manifested by the shift in the RF phase angle for the onset of the detection of photoelectrons via single-photon absorption and allows for a reasonable estimate of the field enhancement factor. This is

Bijaya K. Sahoo, Rajat K. Chaudhuri, B. P. Das, Holger Merlitz

This work presents a first time accurate calculation of the magnetic dipole hyperfine structure constants for the ground state and some low-lying excited states of Pb$^+$. By comparing different levels of approximation with experimental results, we demonstrate the importance of correlation effects which reach beyond lower order relativistic many body perturb

Sebastiaan Y. T. van de Meerakker, Paul H. M. Smeets, Nicolas Vanhaecke, Rienk T. Jongma

A pulsed beam of ground state OH radicals is slowed down using a Stark decelerator and is subsequently loaded into an electrostatic trap. Characterization of the molecular beam production, deceleration and trap loading process is performed via laser induced fluorescence detection inside the quadrupole trap. Depending on details of the trap loading sequence,

P. Parneix, F. Calvo

Unimolecular evaporation in rotating, non-spherical atomic clusters is investigated using Phase Space Theory in its orbiting transition state version. The distributions of the total kinetic energy release epsilon_tr and the rotational angular momentum J_r are calculated for oblate top and prolate top main products with an arbitrary degree of deformation. The

P. Mueller, L. -B. Wang, G. W. F. Drake, K. Bailey

We report on a theoretical calculation and a new experimental determination of the 1s3p ^3P_J fine structure intervals in atomic ^4He. The values from the theoretical calculation of 8113.730(6) MHz and 658.801(6) MHz for the nu_{01} and nu_{12} intervals, respectively, disagree significantly with previous experimental results. However, the new laser spectros

Rudolph C. Hwa, C. B. Yang

The difference between the structures of jets produced in heavy-ion and hadronic collisions can best be exhibited in the correlations between particles within those jets. We study the dihadron correlations in jets in the framework of parton recombination. Two types of triggers, $π^+$ and proton, are considered. It is shown that the recombination of thermal a

R. S. Azevedo, M. Nielsen

In this work we study the energy dependence of the $J/ψ-K^*$ dissociation cross section, using a meson exchange model based on effective hadronic Lagrangian that includes couplings between pseudoscalar and vector mesons. We also consider anomalous parity terms. Off-shell effects at the vertices were handled with QCD sum rule estimates for the running couplin

A. N. Ivanov, M. Cargnelli, M. Faber, H. Fuhrmann

The np pair in the spin-singlet state is treated as a Cooper np-pair within the extension of the Nambu-Jona-Lasinio model of light nuclei, describing the deuteron as a Cooper np-pair in the spin-triplet state. For the Cooper np-pair in the spin-singlet state we compute the binding energy and express the S-wave scattering length of np scattering in the spin-s

H. Krebs, V. Bernard, Ulf-G. Meißner

We show that the Q-box expansion of nuclear many-body physics can be applied in nuclear effective field theory with explicit pions and external sources. We establish the corresponding power counting and give an algorithm for the construction of a hermitean and energy-independent potential for arbitrary scattering processes on nucleons and nuclei to a given o

H. G. Ganev, V. P. Garistov, A. I. Georgieva, J. P. Draayer

In a new application of the algebraic Interacting Vector Boson Model (IVBM), we exploit the reduction of its Sp(12,R) dynamical symmetry group to Sp(4,R) x SO(3), which defines basis states with fixed values of the angular momentum L. The relationship of the latter to $U(6) \subset U(3)x U(2), which is the rotational limit of the model, means the energy dist

Amand Faessler, C. Fuchs, M. I. Krivoruchenko, B. V. Martemyanov

The resonance model is used to analyze the omega- and phi-meson angular distributions in proton-proton collisions at sqrt{s} = 2.83 and 2.98 GeV. The assumption of dominant contributions from N^*(1720)3/2+ and N^*(1900)3/2+ resonances which both have, according to the pi N scattering multichannel partial-wave analysis and/or quark models predictions, dominan

A. Sibirtsev, J. Haidenbauer, J. A. Niskanen, Ulf-G. Meißner

We investigate the relation between the η^3He binding energy and width and the (complex) η^3He scattering length. Following our systematic analysis of the eta 3He scattering length we set limits on the η^3He binding. If bound states exist the binding energy (width) should not exceed 5 MeV (10 MeV). In addition, we comment on a recently claimed observation of

H. Sakaguchi

We study non-locally coupled noisy integrate-and-fire neurons with the Fokker-Planck equation. A propagating pulse state and a wavy state appear as a phase transition from an asynchronous state. We also find a solution in which traveling pulses are emitted periodically from a pacemaker region.

T. G. Elizarova, I. S. Kalachinskaya, Yu. V. Sheretov

We demonstrate the results of the numerical modelling of a plane two-dimensional viscous incompressible flow in a channel with a back-step. As a mathematical model we take equations for a incompressible flow based on the quasi-hydrodynamic (QHD) equations. We present a phenomenological derivation of the QHD equations and show a relation of these equations to

Emanuela Caliceti, Sandro Graffi, Johannes Sjoestrand

Criteria are formulated both for the existence and for the non-existence of complex eigenvalues for a class of non self-adjoint operators in Hilbert space invarariant under a particular discrete symmetry. Applications to the PT-symmetric Schrödinger operators are discussed.

Werner Kirsch, Frederic Klopp

This paper is devoted to the asymptotics of the density of surfacic states near the spectral edges for a discrete surfacic Anderson model. Two types of spectral edges have to be considered : fluctuating edges and stable edges. Each type has its own type of asymptotics. In the case of fluctuating edges, one obtains Lifshitz tails the parameters of which are g

Robert Pollack

Let E/Q be an elliptic curve and let p be an odd supersingular prime for E. In this article, we study the simplest case of Iwasawa theory for elliptic curves, namely when E(Q) is finite, III(E/Q) has no p-torsion and the Tamagawa factors for E are all prime to p. Under these hypotheses, we prove that E(Q_n) is finite and make precise statemens about the size

Frank Schuhmacher

This is an addendum to the paper ``Deformation of $L_\infty$-Algebras'' of the same author. We explain in which way the deformation theory of $L_\infty$-algebras extends the deformation theory of singularities. We show that the construction of semi-universal deformations of $L_\infty$-algebras gives explicit formal semi-universal deformations of isol

M. Dajczer, R. Tojeiro

We provide a local classification of isometric immersions $f\colon L^p\times_ρM^n\to\Q_c^{p+n+k}$ in codimensions $k=1, 2$ of warped products of Riemannian manifolds into space forms, under the assumptions that $n\geq k+1$ and that $N^{p+n}=L^p\times_ρM^n$ has no points with the same constant sectional curvature $c$ as the ambient space form.

Claudio Fontanari

Here we address a Waring type problem for partially symmetric tensors, extending previous work by Massimiliano Mella in the totally symmetric case of forms. In particular, we provide an explicit answer in lower dimensional cases.

Serge Parmentier, Romaric Pujol

We study the relationship between general dynamical Poisson groupoids and Lie quasi-bialgebras. For a class of Lie quasi-bialgebras naturally compatible with a reductive decomposition, we extend the description of the moduli space of classical dynamical r-matrices of Etingof and Schiffmann. We construct, in each gauge orbit, an explicit analytic representati

Federico Pellarin

Nesterenko proved, among other results, the algebraic independence over $\QQ$ of the numbers $π,e^π,Γ(1/4)$. A very important feature of his proof is a multiplicity estimate for quasi-modular forms associated to $\SL_2(\ZZ)$ which involves profound differential properties of certain non-linear differential systems. The aim of this article is to begin the stu

Federico Pellarin

In this article, we extend a multiplicity estimate of Nesterenko, valid for quasi-modular forms associated to $\SL_2(\ZZ)$, to non-holomorphic quasi-modular forms associated to certain co-compact Riemann-Schwarz triangular subgroups of $\SL_2(\CC)$.

Federico Pellarin

An elementary introduction to Hilbert modular forms, with a particular attention to their differential properties: Rankin-Cohen brakets, structure of differential rings... This text will appear in SMF Seminaires et Congres.

Federico Pellarin

Here we characterise in a complete and explicit way the relations of algebraic dependence over $\QQ$ of complex values of Hecke-Mahler series taken at algebraic points of the multiplicative group $\GG_m^2(\CC)$. Our result contains previous theorems by Loxton and van der Poorten, Mahler, and Masser.

Hervé Sabourin

Let $G$ be a real simple Lie group, $\got g$ its Lie algebra. Given a nilpotent adjoint $G$-orbit $O$, the question is to determine the irreducible unitary representations of $G$ that we can associate to $O$, according to the orbit method. P.Torasso, in [22], gave a method to solve this problem if $O$ is minimal. In this paper, we study the case where $O$ is

Juergen Herzog, Takayuki Hibi, Xinxian Zheng

We classify all Cohen-Macaulay chordal graphs. In particular. it is shown that a chordal graph is Cohen-Macaulay if and only if its unmixed.

David Callan

We give several bijections among restricted Motzkin paths, explaining why various parameters on these paths are equidistributed. For example, the number of doublerise-free Motzkin paths of length n is the same as the number of peak-free Motzkin paths of length n+1 and the parameter "number of doublefalls" has the same distribution on the former set a

Annalisa De Bonis, Gyula O. H. Katona, Konrad J. Swanepoel

Let F be a family of subsets of an n-element set not containing four distinct members such that A union B is contained in C intersect D. It is proved that the maximum size of F under this condition is equal to the sum of the two largest binomial coefficients of order n. The maximum families are also characterized. A LYM-type inequality for such families is g

B. Feigin, E. Feigin

Let $ϕ_{\sqrt{2m}}(z)=\sum_{n\in\Z} a_n z^{-n-m}, m\in\N$ be bosonic vertex operator, $L$ some irreducible representation of the vertex algebra $\A_{(m)}$, associated with one-dimensional lattice $\Zl$, generated by vector $l$, $\bra l,l \ket=2m$. Fix some extremal vector $v\in L$. We study the principle subspace $\C[a_i]_{i\in\Z}\cdot v$ and its finitizatio

M. Kashiwara, Pierre Schapira, F. Ivorra, I. Waschkies

Let X be a C-infinity manifold. We construct a microlocalization functor $μ_X$ from the derived category of bounded complexes of ind-sheaves on X to the one on the cotangent bundle of X. This functor generalizes the classical theory of microlocalization.

Federico Rodriguez Hertz, Jana Rodriguez Hertz, Raul Ures

Despite its homotopical stability, new relevant dynamics appear in the isotopy class of a pseudo-Anosov homeomorphism. We study these new dynamics by identifying homotopically equivalent orbits, obtaining a more complete description of the topology of the corresponding quotient spaces, and their stable and unstable sets. In particular, we get some insight on

Terence Tao

Let $G$ be a finite abelian group, and let $f: G \to \C$ be a complex function on $G$. The uncertainty principle asserts that the support $\supp(f) := \{x \in G: f(x) \neq 0\}$ is related to the support of the Fourier transform $\hat f: G \to \C$ by the formula $$ |\supp(f)| |\supp(\hat f)| \geq |G|$$ where $|X|$ denotes the cardinality of $X$. In this note

Eduardo Esteves, Mihnea Popa

Given a smooth projective curve X, we give effective very ampleness bounds for generalized theta divisors on the moduli spaces $SU_X(r,d)$ and $U_X(r,d)$ of semistable vector bundles of rank r and degree d on X with fixed, respectively arbitrary, determinant.

Giuseppe Pareschi, Mihnea Popa

In the present sequel to our previous two papers on regularity on abelian varieties, we give a number of new applications of the theory of $M$-regularity to the study of Seshadri constants, Picard bundles, pluricanonical maps on irregular varieties, and semihomogeneous vector bundles.

Maria Grazia Viola

We give a subfactor construction for a $II_{1}$ factor M which is not anti-isomorphic to itself. The $II_{1}$ factor we consider is essentially the same as the example previously given by Connes. However, our construction uses the recently developed theory of free group factors. We show that there exists an inclusion of $II_{1}$ factors $A\subset B$ which by

Eva Silverstein

The Bousso-Polchinski mechanism for discretely fine-tuning the cosmological constant favors a large bare negative cosmological constant. I argue (using generalizations of results of Klebanov and Tseytlin) that a similar mechanism for fine-tuning the scalar masses to small values favors a large bare negative (i.e. tachyonic) scalar mass. I comment briefly on

K. V. Stepanyantz

Using Schwinger-Dyson equations and Ward identities in N=1 supersymmetric electrodynamics, regularized by higher derivatives, we find, that it is possible to calculate some contributions to the two-point Green function of the gauge field and to the beta-function exactly to all orders of the perturbation theory. The results are applied for the investigation o

E. Corrigan, C. Zambon

It was recently noted how the classical sine-Gordon theory can support discontinuities, or `defects', and yet maintain integrability by preserving sufficiently many conservation laws. Since soliton number is not preserved by a defect, a possible application to the construction of logical gates is suggested.

A. Hebecker

In spontaneously broken supergravity with non-flat potential the vanishing of the cosmological constant is usually associated with a non-trivial balancing of two opposite-sign contributions. We make the simple observation that, in an appropriately defined expansion of the superfield action in inverse powers of $M_P$, this tuning corresponds to the absence of

L. D. Lantsman, V. N. Pervushin

It is shown that, in the theory of interacting Yang -Mills fields and a Higgs field, there is a topological degeneracy of Bogomol'nyi-Prasad-Sommerfield (BPS) monopoles and that there arises, in this case, a chromoelectric monopole characterized by a new topological variable that describes transitions between topological states of the monopole in the Min

A. A. Slavnov

Gauge independence of dimension two condensate in Yang-Mills theory is demonstrated by using a noncommutative theory technique.

Maciej A. Nowak

We explain the main idea of the chiral doublers scenario, originating from simultaneous constraints of chiral symmetry and of heavy quark spin symmetry on effective theories of heavy-light hadrons. In particular we discuss chiral doublers for mesons, chiral doublers for excited mesons, chiral doublers for baryons and chiral doublers for excited baryons. We p

Hilmar Forkel

We outline a comprehensive study of spin-0 glueball properties which, in particular, keeps track of the topological gluon structure. Specifically, we implement (semi-hard) topological instanton physics as well as topological charge screening in the QCD vacuum into the operator product expansion (OPE) of the glueball correlators. A realistic instanton size di

Wilfried Buchmuller

Neutrino masses and mixings are very different from quark masses and mixings. This puzzle is a crucial hint in the search for the mechanism which determines fermion masses in grand unified theories. We study the flavour problem in an SO(10) GUT model in six dimensions compactified on an orbifold. Three sequential families are localized at three branes where

J. P. Lansberg, F. Bissey, J. R. Cudell, J. Cugnon

We present here an extension of our model for the pion, which we used previously to calculate its diagonal structure function, to the off-forward case. The imaginary part of the off-forward gamma^* pi -> gamma^* pi scattering amplitude is evaluated in the chiral limit (m_pi=0) and related to the twist-two and twist-three generalised parton distributions H, H

Jean Alexandre, K. Farakos, N. E. Mavromatos

In this article we derive the anomalous magnetic moment of fermions in (2+1)-dimensional parity-conserving QED3, in the presence of an externally applied constant magnetic field. We use a spectral representation of the photon propagator to avoid infrared divergences. We also discuss the scaling with the magnetic field intensity in the case of strong external

Yuan-Ben Dai, Chao-Shang Huang, Wen-Jun Li, Xiao-Hong Wu

We study the $B\to ϕK_S$ decay in a SUSY SO(10) GUT. We calculate the mass spectrum of sparticles for a given set of parameters at the GUT scale. We complete the calculations of the Wilson coefficients of operators including the new operators which are induced by NHB penguins at LO using the MIA with double insertions. It is shown that the recent experimenta

J. R. Forshaw, R. Sandapen, G. Shaw

We compare the predictions of two distinct dipole models for inclusive and exclusive diffractive processes. While only one of these dipole models contains perturbative saturation dynamics, we show that the predictions of both models are fully consistent with the available HERA data, indicating no compelling evidence for saturation at present HERA energies.

Sean Fleming, Adam K. Leibovich

We study the evolution of flavor-singlet, light-cone amplitudes in the soft-collinear effective theory (SCET), and reproduce results previously obtained by a different approach. We apply our calculation to the color-singlet contribution to the photon endpoint in radiative Upsilon decay. In a previous paper, we studied the color-singlet contributions to the e

Jason Minamora

A mass Hierarchy of magnitude O(10^16) GeV separates the gravitational and electroweak interactions. Traditional proposed resolutions of this anomaly have included supersymmetric theories (most notably, the MSSM and ESSM) and string theory. However, energiers at which supersymmetric particles are expected to appear are not accessible to experiment, and strin

Ofer Lahav, Andrew R Liddle

Pre-publication version withdrawn at the request of the journal. Final version now available in Reviews of Particle Physics at http://pdg.lbl.gov/2004/reviews/contents_sports.html

Norikazu Yamada, Sinya Aoki, Yoshinobu Kuramashi

We determine the mass dependent renormalization as well as improvement coefficients for the heavy-light vector and axial-vector currents consisting of the relativistic heavy and the domain-wall light quarks through the standard matching procedure. The calculation is carried out perturbatively at the one loop level to remove the systematic error of $O(α_s (am

Kurt Langfeld

SU(3) lattice gauge theory is studied by means of an improved action where a $2 \times 2$ Wilson loop is supplemented to the standard plaquette term. By contrast to earlier studies using a tree level improvement, the prefactor of the $2 \times 2$ Wilson term is determined by minimizing the breaking of rotational symmetry detected from the static quark-antiqu

Bill Rosgen, John Watrous

This paper considers the following problem. Two mixed-state quantum circuits Q and R are given, and the goal is to determine which of two possibilities holds: (i) Q and R act nearly identically on all possible quantum state inputs, or (ii) there exists some input state that Q and R transform into almost perfectly distinguishable outputs. This problem may be

S. V. Kalinin, J. Shin, G. M. Veith, A. P. Baddorf

The origins of an ultrahigh dielectric constant in polycrystalline CaCu3Ti4O12 (CCTO) was studied using the combination of impedance spectroscopy, electron microscopy, and scanning probe microscopy (SPM). Impedance spectra indicate that the transport properties in the 0.1 Hz .. 1 MHz frequency range are dominated by a single parallel resistive-capacitive (RC

Youichi Yanase

The pseudogap phenomena induced by the SC fluctuation are investigated in details. We perform a calculation beyond the 1-loop approximation. The SC fluctuation is microscopically derived on the basis of the repulsive Hubbard model. The vertex corrections are collected in the infinite order with use of the quasi-static approximation. The single-particle excit

Xavier Blase, Ch Adessi, Damien Connetable

We present an {\it ab initio} study of the recently discovered superconductivity of boron doped diamond within the framework of a phonon-mediated pairing mechanism. The role of the dopant, in substitutional position, is unconventional in that half of the coupling parameter $λ$ originates in strongly localized defect-related vibrational modes, yielding a very

I. A. Agaev, Yu. A. Kuperin

This paper is devoted to problem of detecting critical events at finiacial markets using methods of multifractal analysis. Namely, the local regularity of time-series is studied. As a result, one can find out a special behavior or signal of regularity before crashes. This spesial behaviour of local Hoelder exponents inherent in financial time series can be u

A. B. Zorin

The Cooper pair box qubit of SQUID configuration enables the readout of the qubit states by probing the effective Josephson inductance of the SQUID. This is realized by coupling the qubit to a tank circuit which induces a small alternating supercurrent in the SQUID loop. The effect of a small (but finite) geometrical inductance of the loop on the eigenstates