June 2002 arXiv papers — page 23

N. J. Rodriguez-Fernandez, J. Martin-Pintado, P. de Vicente, A. Fuente

We present some recent studies on the physical conditions and the chemistry of the interstellar medium (ISM) in the Galactic center region (GCR). Large scale shocks in the context of a bar potential can play a role in explaining the observed properties, at least in some particular regions. Alternatively, we propose that the observed properties (inhomogeneity

M. Kramer

The understanding of pulsar radio emission demands a close look at all regions of the huge parameter space present for pulsar observations. In this review we concentrate on the space given by the range of observed pulse periods, spanning four orders of magnitude. A comparative study of the emission properties of millisecond pulsars and normal pulsars, both a

N. J. Rodriguez-Fernandez, J. Martin-Pintado, P. de Vicente

We present Infrared Space Observatory (ISO) observations of fine structure lines toward the Radio Arc region, close to Sgr A, in the Galactic center region (GCR). The ionization at large scale is dominated by the clusters of massive stars in this region: the Quintuplet and the Arches cluster. Any other possible mechanism as interaction with the magnetic fiel

P. G. Tuthill, J. D. Monnier, W. C. Danchi, D. D. S. Hale

The Herbig Ae/Be star LkHalpha 101 has been imaged at high angular resolution at a number of wavelengths in the near-infrared (from 1 to 3 microns) using the Keck 1 Telescope, and also observed in the mid-infrared (11.15 microns) using the U.C. Berkeley Infrared Spatial Interferometer (ISI). The resolved circular disk with a central hole or cavity reported i

Henk Hoekstra, Ludo van Waerbeke, Michael D. Gladders, Yannick Mellier

We combine weak lensing measurements from the Red-Sequence Cluster Survey and the VIRMOS-DESCART survey, and present the first direct measurements of the bias parameter b and the galaxy-mass cross-correlation coefficient r on scales ranging from 0.2 to 9.3 h_{50}^{-1} Mpc at a lens redshift z~0.35. We find strong evidence that both b and r change with scale

Vadim Borokhov, Anton Kapustin, Xinkai Wu

Many abelian gauge theories in three dimensions flow to interacting conformal field theories in the infrared. We define a new class of local operators in these conformal field theories which are not polynomial in the fundamental fields and create topological disorder. They can be regarded as higher-dimensional analogues of twist and winding-state operators i

W. A. T. Nogueira, S. P. Walborn, S. Padua, C. H. Monken

The theoretical framework behind a recent experiment by Nogueira et. al. [Phys. Rev. Lett. 86}, 4009 (2001)] of spatial antibunching in a two-photon state generated by collinear type II parametric down-conversion and a birefringent double-slit is presented. The fourth-order quantum correlation function is evaluated and shown to violate the classical Schwarz-

Daniel Zwanziger

We derive the equations of time-independent stochastic quantization, without reference to an unphysical 5th time, from the principle of gauge equivalence. It asserts that probability distributions $P$ that give the same expectation values for gauge-invariant observables $<W > = \int dA W P$ are physically indistiguishable. This method escapes the Gribov crit

Adam C. Durst, Ashvin Vishwanath, Patrick A. Lee

Thermal transport in the mixed state of a d-wave superconductor is considered within the weak-field regime. We express the thermal conductivity, $κ_{xx}$, and the thermal Hall conductivity, $κ_{xy}$, in terms of the cross section for quasiparticle scattering from a single vortex. Solving for the cross section (neglecting the Berry phase contribution and the

Pablo Alberca Bjerregaard, Candido Martin Gonzalez

We present in this paper all the details for a complete description of the Lie algebra a in the split case at any characteristic. We finish with the determination of the expression of a generic element of this algebra. First of all is necessary to implement its quadratic Jordan structure (see the O. Loss&#39; server http://mathematik.uibk.ac.at/jordan for ou

Andrew Chamblin, Gouranga C. Nayak

If the fundamental planck scale is near a TeV, then parton collisions with high enough center-of-mass energy should produce black holes. The production rate for such black holes at LHC has been extensively studied for the case of a proton-proton collision. In this paper, we extend this analysis to a lead-lead collision at LHC. We find that the cross section

Xiangdong Ji, Feng Yuan

We show that the final-state interaction effects in the single target spin asymmetry discovered by Brodsky et al. can be reproduced by either a standard light-cone gauge definition of the parton distributions with a prescription of the light-cone singularities consistent with the light-cone gauge link, or a modified light-cone gauge definition with a gauge l

Neil Cornish, Shane Larson

The orbital motion of the Laser Interferometer Space Antenna (LISA) produces amplitude, phase and frequency modulation of a gravitational wave signal. The modulations have the effect of spreading a monochromatic gravitational wave signal across a range of frequencies. The modulations encode useful information about the source location and orientation, but th

S. N. Evangelou, D. E. Katsanos

We describe the singularities in the averaged density of states and the corresponding statistics of the energy levels in two- (2D) and three-dimensional (3D) chiral symmetric and time-reversal invariant disordered systems, realized in bipartite lattices with real off-diagonal disorder. For off-diagonal disorder of zero mean we obtain a singular density of st

Ezio Bruno, Leon Zingales, Antonio Milici

Electronic structure calculations performed on very large supercells have shown that the local charge excesses in metallic alloys are related through simple linear relations to the local electrostatic field resulting from distribution of charges in the whole crystal. By including local external fields in the single site Coherent Potential Approximation theor

Geraldine Servant, Tim M. P. Tait

In models with universal extra dimensions (i.e. in which all Standard Model fields, including fermions, propagate into compact extra dimensions) momentum conservation in the extra dimensions leads to the conservation of Kaluza--Klein (KK) number at each vertex. KK number is violated by loop effects because of the orbifold imposed to reproduce the chiral Stan

V. V. Varlamov

A group theoretical description of the Majorana-Oppenheimer quantum electrodynamics is considered. Different spinor realizations of the Maxwell and Dirac fields are discussed. A representation of the Majorana-Oppenheimer wave equations in terms of the Gel&#39;fand-Yaglom formalism is given.

P. Contucci, M. Degli Esposti, C. Giardina, S. Graffi

Let $\{E_{\s}(N)\}_{\s\inΣ_N}$ be a family of $|Σ_N|=2^N$ centered unit Gaussian random variables defined by the covariance matrix $C_N$ of elements $\displaystyle c_N(\s,τ):=\av{E_{\s}(N)E_τ(N)}$, and $H_N(\s) = - \sqrt{N} E_{\s}(N)$ the corresponding random Hamiltonian. Then the quenched thermodynamical limit exists if, for every decomposition $N=N_1+N_2$,

Sergio De Rinaldis, Irene D&#39;Amico, Fausto Rossi

We present a fully three-dimensional study of the multiexciton optical response of vertically coupled GaN-based quantum dots via a direct-diagonalization approach. The proposed analysis is crucial in understanding the fundamental properties of few-particle/exciton interactions and, more important, may play an essential role in the design/optimization of semi

Stefan Dittmaier, Markus Roth

LUSIFER is a Monte Carlo event generator for all processes e+e-->6fermions, which is based on the multi-channel Monte Carlo integration technique and employs the full set of tree-level diagrams. External fermions are taken to be massless, but can be arbitrarily polarized. The calculation of the helicity amplitudes and of the squared matrix elements is presen

D. Arnaudon, A. Chakrabarti, V. K. Dobrev, S. G. Mihov

We find the exotic matrix bialgebras which correspond to the two non-triangular nonsingular 4x4 R-matrices in the classification of Hietarinta, namely, R_{S0,3} and R_{S1,4}. We find two new exotic bialgebras S03 and S14 which are not deformations of the of the classical algebras of functions on GL(2) or GL(1|1). With this we finalize the classification of t

K. Scharnhorst

The present study introduces and investigates a new type of equation which is called Grassmann integral equation in analogy to integral equations studied in real analysis. A Grassmann integral equation is an equation which involves Grassmann integrations and which is to be obeyed by an unknown function over a (finite-dimensional) Grassmann algebra G_m. A par

M. Mueller, T. Vekua, H. -J. Mikeska

The isotropic S=1/2 antiferromagnetic spin ladder with additional four-spin ring exchange is studied perturbatively in the strong coupling regime with the help of cluster expansion technique, and by means of bosonization in the weak coupling limit. It is found that a sufficiently large strength of ring exchange leads to a second-order phase transition, and t

Y. P. Jing

We use a large set of state-of-the-art cosmological N-body simulations [512^3 particles] to study the intrinsic ellipticity correlation functions of halos. With the simulations of different resolutions, we find that the ellipticity correlations converge once the halos have more than 160 members. For halos with fewer members, the correlations are underestimat

L. W. Garland, T. Gehrmann, E. W. N. Glover, A. Koukoutsakis

We compute the two-loop QCD helicity amplitudes for the process e^+e^- --> q bar{q} g. The amplitudes are extracted in a scheme-independent manner from the coefficients appearing in the general tensorial structure for this process. The tensor coefficients are derived from the Feynman graph amplitudes by means of projectors, within the conventional dimensiona

J. Gasser, M. A. Ivanov, E. Lipartia, M. Mojzis

We investigate the ground-state energy of the pi- p atom (pionic hydrogen) in the framework of QCD+QED. In particular, we evaluate the strong energy-level shift. We perform the calculation at next-to-leading order in the low-energy expansion in the framework of the relevant effective field theory. The result provides a relation between the strong energy shif

Alexander Feinstein

We show how the Szekeres form of the line element is naturally adapted to study Penrose limits in classical string backgrounds. Relating the &#34;old&#34; colliding wave problem to the Penrose limiting procedure as employed in string theory we discuss how two orthogonal Penrose limits uniquely determine the underlying target space when certain symmetry is im

Sumiyoshi Abe

The q-exponential distributions, which are generalizations of the Zipf-Mandelbrot power-law distribution, are frequently encountered in complex systems at their stationary states. From the viewpoint of the principle of maximum entropy, they can apparently be derived from three different generalized entropies: the Renyi entropy, the Tsallis entropy, and the n

Markus Perling

We describe the construction of a class of toric varieties as spectra of homogeneous prime ideals.

Suhan Ree

Using fractal analysis, we investigate how the size of openings affects the chaotic behavior of a classical closed billiard when two openings are made on the boundary of the billiard. This kind of open billiards retains chaotic properties of original closed billiards when openings are small compared to the size of the billiard. We calculate the fractal dimen

Timothy J. Hollowood, S. Prem Kumar

In this note we explore the stringy interpretation of non-perturbative effects in N=1^* deformations of the A_{k-1} quiver models. For certain types of deformations we argue that the massive vacua are described by Nk fractional D3-branes at the orbifold polarizing into k concentric 5-brane spheres each carrying fractional brane charge. The polarization of th

Hiroshi Igarashi, Kiyoshi Okuyama, Hiroshi Suzuki

We study the axial anomaly defined on a finite-size lattice by using a Dirac operator which obeys the Ginsparg-Wilson relation. When the gauge group is U(1), we show that the basic structure of axial anomaly on the infinite lattice, which can be deduced by a cohomological analysis, persists even on (sufficiently large) finite-size lattices. For non-abelian g

X. Bekaert, N. Boulanger, J. F. Vazquez-Poritz

In an attempt to bridge the gap between M-theory and braneworld phenomenology, we present various gravitational Lorentz-violating braneworlds which arise from p-brane systems. Lorentz invariance is still preserved locally on the braneworld. For certain p-brane intersections, the massless graviton is quasi-localized. This also results from an M5-brane in a C-

F. J. Perez-Reche, Eduard Vives

A numerical study is presented of the 3d Gaussian Random Field Ising Model at T=0 driven by an external field. Standard synchronous relaxation dynamics is employed to obtain the magnetization versus field hysteresis loops. The focus is on the analysis of the number and size distribution of the magnetization avalanches. They are classified as being non-spanni

Leo Liberti

We perform a comparison of the performance and efficiency of four different function evaluation methods: black-box functions, binary trees, $n$-ary trees and string parsing. The test consists in evaluating 8 different functions of two variables $x,y$ over 5000 floating point values of the pair $(x,y)$. The outcome of the test indicates that the $n$-ary tree

Gary W. Gibbons, Daisuke Ida, Tetsuya Shiromizu

We prove a uniqueness theorem for asymptotically flat static charged dilaton black hole solutions in higher dimensional space-times. We also construct infinitely many non-asymptotically flat regular static black holes on the same space-time manifold with the same spherical topology. An application to the uniqueness of a certain class of flat $p$-branes is al

Thomas Schaefer

We study instantons in QCD with many colors. We first discuss a number of qualitative arguments concerning the large N_c scaling behavior of a random instanton ensemble. We show that most hadronic observables are compatible with standard large N_c counting rules provided the average instanton size is O(1) and the instanton density is O(N_c) in the large N_c

Belle Collaboration, K. Abe

We report the first observation of the decay B^0->D+-D*-+ with the Belle detector at the KEKB e^+e^- collider operated at the Upsilon(4S) resonance. The sum of branching fractions B(B^0->D+D*-)+B(B^0->D-D*+) is measured to be (1.17+-0.26+0.22-0.25)x10^-3 using the full reconstruction method where both charmed mesons from B^0 decays are reconstructed. A consi

X. -G. He, C. -P. Kao, J. P. Ma, S. Pakvasa

In this paper we investigate the possibility of studying $B\to π$ form factor using the semi-inclusive decays $\bar B^0 \to π^+ + X_q$. In general $B\to PX$ semi-inclusive decays involve several hadronic parameters. But for $\bar B^0 \to π^+ X_q$ decays we find that in the factorization approximation, the only unknown hadronic parameters are the form factors

G. Flores-Hidalgo

The bare one loop soliton quantum mass corrections can be expressed in two ways: as a sum over the zero-point energies of small oscillations around the classical configuration, or equivalently as the (Euclidean) effective action per unit time. In order to regularize the bare one loop quantum corrections (expressed as the sum over the zero-point energies) we

Valeri Frolov, Dejan Stojkovic

A black hole attached to a brane in a higher dimensional space emitting quanta into the bulk may leave the brane as a result of a recoil. We study this effect. We consider black holes which have a size much smaller than the characteristic size of extra dimensions. Such a black hole can be effectively described as a massive particle with internal degrees of f

W. A. T. Nogueira, S. P. Walborn, S. Padua, C. H. Monken

We report an interference experiment that shows transverse spatial antibunching of photons. Using collinear parametric down-conversion in a Young-type fourth-order interference setup we show interference patterns that violate the classical Schwarz inequality and should not exist at all in a classical description.

M. S. Kim, Jinhyoung Lee, W. J. Munro

Measures of entanglement, fidelity and purity are basic yardsticks in quantum information processing. We propose how to implement these measures using linear devices and homodyne detectors for continuous variable Gaussian states. In particular, the test of entanglement becomes simple with some prior knowledge which is relevant to current experiments.

Qiong-Gui Lin

A wave packet of a charged particle always make cyclic circular motion in a uniform magnetic field, just like a classical particle. The nonadiabatic geometric phase for an arbitrary wave packet can be expressed in terms of the mean value of a number operator. For a large class of wave packets, the geometric phase is proportional to the magnetic flux encircle

Thomas Breuer

Unsharp spin 1 observables arise from the fact that a residual uncertainty about the actual orientation of the measurement device remains. If the uncertainty is below a certain level, and if the distribution of measurement errors is covariant under rotations, a Kochen-Specker theorem for the unsharp spin observables follows: There are finite sets of directio

D. Olevik, C. Turk, H. Wiklund, J. Hansson

We discuss an experiment conducted by Nesvizhevsky et al. As it is the first experiment claimed to have observed gravitational quantum states, it is imperative to investigate all alternative explanations of the result. In a student project course in applied quantum mechanics, we consider the possibility of quantummechanical effects arising from the geometry

Dominique Delande, Krzysztof Sacha, Jakub Zakrzewski

We show that combination of a linearly polarized resonant microwave field and a parallel static electric field may be used to create a non-dispersive electronic wavepacket in Rydberg atoms. The static electric field allows for manipulation of the shape of the elliptical trajectory the wavepacket is propagating on. Exact quantum numerical calculations for rea

G. Levai, F. Cannata, A. Ventura

Closed expressions are derived for the pseudo-norm, norm and orthogonality relations for arbitrary bound states of the PT symmetric and the Hermitian Scarf II potential for the first time. The pseudo-norm is found to have indefinite sign in general. Some aspects of the spontaneous breakdown of PT symmetry are analysed.

Dagomir Kaszlikowski, L. C. Kwek, Jingling Chen, C. H. Oh

It was shown in Phys. Rev. Lett., 87, 230402 (2001) that N (N >= 4) qubits described by a certain one parameter family F of bound entangled states violate Mermin-Klyshko inequality for N >= 8. In this paper we prove that the states from the family F violate Bell inequalities derived in Phys. Rev. A, 56, R1682 (1997), in which each observer measures three non

Alexander Bulinski, Andrei Khrennikov

Interpretation of the nonclassical total probability formula arising in some quantum experiments is provided based on stochastic models described by means of a sequence of random vectors changing in the measurement procedures.

Omar Benhar

I review the available empirical information on the equation of state of cold strongly interacting matter, as well as the prospects for obtaining new insights from the experimental study of gravitational waves emitted by neutron stars.

Girish Nathan

A simple algorithm is described to target any desired operation point for simple one-dimensional and two-dimensional dynamical systems. What makes the algorithm unique is the fact that it targets any desired point, not merely a stable/unstable fixed point of the dynamics. It is shown how the method may be applied to the logistic map and the Hénon map. Genera

M. C. Nucci, P. G. L. Leach

The symmetry approach to the determination of Jacobi&#39;s last multiplier is inverted to provide a source of additional symmetries for the Euler-Poinsot system. These additional symmetries are nonlocal. They provide the symmetries for the representation of the complete symmetry group of the system.

David C. Brydges, John Z. Imbrie

In [BEI] we introduced a Levy process on a hierarchical lattice which is four dimensional, in the sense that the Green&#39;s function for the process equals 1/x^2. If the process is modified so as to be weakly self-repelling, it was shown that at the critical killing rate (mass-squared) β^c, the Green&#39;s function behaves like the free one. - Now we analyz

Benoit Collins

We consider integrals on unitary groups $U_d$ of the form $$\int_{U_d}U_{i_1j_1}... U_{i_qj_q}U^*_{j&#39;_{1}i&#39;_{1}} ... U^*_{j&#39;_{q&#39;}i&#39;_{q&#39;}}dU$$ We give an explicit formula in terms of characters of symmetric groups and Schur functions, which allows us to rederive an asymptotic expansion as $d\to\infty$. Using this we rederive and streng

M. Junge

Let $1\le p<\8$ and $(x_n)_{\nen}$ be a sequence of positive elements in a non-commutative $L_p$ space and $(E_n)_{\nen}$ be an increasing sequence of conditional expectations, then the $L_p$ norm of \sum_n E_n(x_n) can be estimated by c_p times the $L_p$ norm of \sum_n x_n. This inequality is due to Burkholder, Davis and Gundy in the commutative case. By du

M. Junge, N. Ozawa, Z. J. Ruan

We study the local operator space structure of nuclear $C^*$-algebras. It is shown that a $C^*$-algebra is nuclear if and only if it is an $\OL_{\infty, \la}$ space for some (and actually for every) $\la > 6$. The $\OL_\infty$ constant $λ$ provides an interesting invariant \[ \OL_\infty (\A) = \inf\{\la: ~ \A ~{\rm is ~ an} ~ {\OL}_{\infty, \la} ~ {\rm space

M. Junge, Z. -J. Ruan

Let $1 < p < \infty$. It is shown that if $G$ is a discrete group with the approximation property introduced by Haagerup and Kraus, then the non-commutative $L_p(VN(G))$ space has the operator space approximation property. If, in addition, the group von Neumann algebra $VN(G)$ has the QWEP, i.e. is a quotient of a $C^*$-algebra with Lance&#39;s weak expectat

Tim D. Cochran, Kent E. Orr, Peter Teichner

We provide new information about the structure of the abelian group of topological concordance classes of knots in $S^3$. One consequence is that there is a subgroup of infinite rank consisting entirely of knots with vanishing Casson-Gordon invariants but whose non-triviality is detected by $L^{(2)}$ signatures.

Peter Schneider, Jeremy Teitelbaum

Let G be a compact, locally L-analytic group, where L is a finite extension of Qp. Let K be a discretely valued extension field of L. We study the algebra D(G,K) of K-valued locally analytic distributions on G, and apply our results to the locally analytic representation theory of G in vector spaces over K. Our objective is to lay a useful and powerful found

Norbert Peyerimhoff, Evangelia Samiou

We show that the Cheeger isoperimetric constant of a solvable simply connected Lie group $G$ with Lie algebra $\G$ is $h(G)=\max_{H\in\G,||H||=1} \tr(\ad (H))$.

Kevin M. Pilgrim, Tan Lei

We analyze a real one-parameter family of quasiconformal deformations of a hyperbolic rational map known as {\em spinning}. We show that under fairly general hypotheses, the limit of spinning either exists and is unique, or else converges to infinity in the moduli space of rational maps of a fixed degree. When the limit exists, it has either a parabolic fixe

L. A. Nazarova, A. V. Roiter

Numerical functions, which characterize Dynkin schemes, Coxeter graphs and tame marked quivers, are considered.

Alan L. Carey, Bai-Ling Wang

This paper gives a detailed construction of Seiberg-Witten-Floer homology for a closed oriented 3-manifold with a non-torsion $\spinc$ structure. Gluing formulae for certain 4-dimensional manifolds splitting along an embedded 3-manifold are obtained.

Jianhua Wang

We discuss the relationship between the m-th homotopy group of the one-point union of r copies of the two-dimensional sphere and the m-th homotopy group of the one-point union of r+1 copies of the Thom space of the oriented two-dimensional universal vector bundle. Using a suitably choosen isomorphism between them a forgetful homomorphism is computed by evalu

Joerg Zintl

The theorem of Barth-Lefschetz is a statement about the cohomology of a submanifold X of some projective space, in a range depending on the codimension of the embedding. Here this is generalized to the case of a submanifold X of a smooth projective toric variety Y, under some natural conditions on X. In particular, in the Barth-Lefschetz range a formula for

H. Huffel

We review the Batalin-Vilkovisky quantization procedure for Yang--Mills theory on a 2-point space.

Dominic Brecher, Clifford V. Johnson, Kenneth J. Lovis, Robert C. Myers

A certain conformally invariant N=1 supersymmetric SU(n) gauge theory has a description as an infra-red fixed point obtained by deforming the N=4 supersymmetric Yang-Mills theory by giving a mass to one of its N=1 chiral multiplets. We study the Penrose limit of the supergravity dual of the large n limit of this N=1 gauge theory. The limit gives a pp-wave wi

Mauricio Ayala, Richard Haase

We investigate the group contraction method for various space-time groups, including SO(3)->E_2, SO(3,1)->G_3, SO(5-h,h)->P(3,1) (h=1 or 2), and its consequences for representations of these groups. Following strictly quantum mechanical procedures we specifically pay attention in the asymptotic limiting procedure employed in the contraction G -> G&#39;, not

Yoshiki Hiraoka

We study the 1/4 BPS equations in the eight dimensional noncommutative Yang-Mills theory found by Bak, Lee and Park. We explicitly construct some solutions of the 1/4 BPS equations using the noncommutative version of the ADHM-like construction in eight dimensions. From the calculation of topological charges, we show that our solutions can be interpreted as t

K. Tsushima

The effect of changes in hadron properties in a nuclear medium on physical observables is discussed. Highlighted results are, (1) hypernuclei, (2) meosn-nuclear bound states, (3) $K$-meson production in heavy ion collisions, and (4) $J/Ψ$ dissociation in a nuclear medium. In addition, results for the near-threshold $ω$- and $ϕ$-meson productions in proton pr

Masaaki Fujii, T. Yanagida

We show that a class of Affleck--Dine baryogenesis directly relates the observed mass density of baryons, Ω_{B}, to that of dark matter, Ω_{DM}. In this scenario, the ratio of baryon to dark matter mass density is solely determined by the low energy parameters, except for an O(0.1) effective CP-violating phase. We find that Ω_{B}/Ω_{DM}=O(0.1) with reasonabl

G. Nardulli

In the high density, low temperature limit, Quantum Chromodynamics exhibits a transition to phases characterized by color superconductivity and energy gaps in the fermion spectra. We review some fundamental results obtained in this area and in particular we describe the low energy effective lagrangian describing the motion of the quasi-particles in the high

Yosef Nir, Guy Raz

We re-examine the possibility that the solution to the supersymmetric flavor problem is related to small mixing angles in gaugino couplings induced by approximate horizontal Abelian symmetries. We prove that, for a large class of models, there is a single viable structure for the down quark mass matrix with four holomorphic zeros. Consequently, we are able t

John P. Ralston, Roman V. Buniy, Pankaj Jain

A new picture is given of generalized parton distributions probed in experiments in which the probe scale $Q^{2}$ and the momentum transfer $\DD^{2}$ are well separated. Application of this picture to the $Q^{2}$ dependence of the form factors $F_{1}, F_{2}$ shows that gauge invariant quark orbital angular momentum can be measured and indeed {\it localized}

Philip Yock

A previously proposed unified field theory of electro-strong interactions requires two scales of length within hadrons, $\sim10^{-15}m$ and $\sim10^{-18}m$ respectively, and the onset of new phenomena at the shorter scale. Studies at the HERA electron-proton collider at the shorter scale have revealed a possible excess of high-transverse momentum events, as

Thomas E. Coan

The CLEO collaboration at the Cornell Electron Storage Ring (CESR) is proposing a three-year experiment that specifically emphasizes charm and QCD studies in the energy range $\sqrt{s}=3$--$5 $GeV, utilizes the existing detector and requires minimal modification of CESR to produce a luminosity ${\cal{L}}=(1-5)\times10^{32} {\rm cm^{-2}sec^{-1}}$. Key feature

J. M. Link

We have studied the Cabibbo suppressed decay (Λ_{c}^{+}\to Σ^{+}K^{*0}(892)) and the Cabibbo favored decays (Λ_{c}^{+}\to Σ^{+}K^{+}K^{-}), (Λ_{c}^{+}\to Σ^{+}ϕ) and (Λ_{c}^{+}\to Ξ^{*0}(Σ^{+}K^{-})K^{+}) and measured their branching ratios relative to (Λ_{c}^{+}\to Σ^{+}π^{+}π^{-}) to be ((7.8\pm 1.8\pm 1.3)%), ((7.1\pm 1.1\pm 1.1)%), ((8.7\pm 1.6\pm 0.6)%)

M. F. A. da Silva, L. Herrera, N. O. Santos, A. Z. Wang

Rotating thin-shell-like sources for the stationary cylindrically symmetric vacuum solutions (Lewis) are constructed and studied. It is found, by imposing the non existence of timelike curves in the exterior of the shell, and that the source satisfies the weak, dominant and strong energy conditions that the parameters, commonly denoted by $a$ and $σ$, are re

O. B. Zaslavskii

In some kinds of classical dilaton theory there exist black holes with (i) infinite horizon area $A$ or infinite $F$ (the coefficient at curvature in Lagrangian) and (ii) zero Hawking temperature $T_{H}$. For a generic static black hole, without an assumption about spherical symmetry, we show that infinite $A$ is compatible with a regularity of geometry in t

George Papanicolaou, Leonid Ryzhik, Knut Solna

When a signal is emitted from a source, recorded by an array of transducers, time reversed and re-emitted into the medium, it will refocus approximately on the source location. We analyze the refocusing resolution in a high frequency, remote sensing regime, and show that, because of multiple scattering, in an inhomogeneous or random medium it can improve bey

Michael Lassig

A systematic theory is introduced that describes stochastic effects in game theory. In a biological context, such effects are relevant for the evolution of finite populations with frequency-dependent selection. They are characterized by quantum Nash equilibria, a generalization of the well-known Nash equilibrium points in classical game theory. The implicati

Sara Bergkvist, Patrik Henelius, Anders Rosengren

Stochastic series expansion quantum Monte Carlo is used to study the ground state of the antiferromagnetic spin-1 Heisenberg chain with bond disorder. Typical spin- and string-correlations functions behave in accordance with real-space renormalization group predictions for the random-singlet phase. The average string-correlation function decays algebraically

L. L. A. Adams, Klaus Halterman, Oriol T. Valls, A. M. Goldman

The magnetic field and temperature dependencies of the magnetic moments of superconducting crystals of ${\rm V_{3}Si}$ have been studied. In a constant magnetic field and at temperatures somewhat below the superconducting transition temperature, the moments are hysteretic in temperature. However the magnetic moment-magnetic field isotherms are reversible and

Henning Arendt Knudsen, Alex Hansen

We report on generic relations between fractional flow and pressure in steady two-phase flow in porous media. The main result is a differential equation for fractional flow as a function of phase saturation. We infer this result from two underlying observations of steady flow simulations in two and three dimensions using biperiodic boundary conditions. The r

Krzysztof Byczuk

The low-energy electronic Hamiltonian for the thinest zigzag carbon nanotube, embedded into a dielectric host, is derived and its phase diagram is discussed. The specific multi-band structure and the microscopic form of the electron-electron interaction in this systems is considered. The interband repulsive interaction, which is almost unscreened, leads to a

A. Vazquez, R. Pastor-Satorras, A. Vespignani

We present a statistical analysis of different metrics characterizing the topological properties of Internet maps, collected at two different resolution scales: the router and the autonomous system level. The metrics we consider allow us to confirm the presence of scale-free signatures in several statistical distributions, as well as to show in a quantitativ

David Hochberg, Juan Pérez-Mercader

We find that in generic field theories the combined effect of fluctuations and interactions leads to a probability distribution function which describes fractional Brownian Motion (fBM) and ``complex behavior&#39;&#39;. To show this we use the Renormalization Group as a tool to improve perturbative calculations, and check that beyond the classical regime of

G. R. Blake, L. Chapon, P. G. Radaelli, D. N. Argyriou

The phase diagram of Pr0.65(CaySr1-y)0.35MnO3, 0.6 <= y <= 0.8, has been determined by neutron diffraction, magnetization and electrical conductivity measurements in order to investigate the nature of the transition between ferromagnetic metallic and charge-ordered insulating states near y=0.75. Two possible scenarios for this transition have been proposed:

Stefano Fabris, Anthony T. Paxton, Michael W. Finnis

The microscopic mechanism leading to stabilization of cubic and tetragonal forms of zirconia (ZrO$_2$) is analyzed by means of a self-consistent tight-binding model. Using this model, energies and structures of zirconia containing different vacancy concentrations are calculated, equivalent in concentration to the charge compensating vacancies associated with

Carlos P. Herrero

The Ising model in small-world networks generated from two- and three-dimensional regular lattices has been studied. Monte Carlo simulations were carried out to characterize the ferromagnetic transition appearing in these systems. In the thermodynamic limit, the phase transition has a mean-field character for any finite value of the rewiring probability p, w

R. Guimera, A. Arenas, A. Diaz-Guilera, F. Giralt

We study the dynamical properties of a collection of models for communication processes, characterized by a single parameter $ξ$ representing the relation between information load of the nodes and its ability to deliver this information. The critical transition to congestion reported so far occurs only for $ξ=1$. This case is well analyzed for different netw

M. Dressel, N. Drichko, J. Schlueter, J. Merino

While the optical properties of the superconducting salt $α$-(BEDT-TTF)$_2$NH$_4$Hg(SCN)$_4$ remain metallic down to 2 K, in the non-superconducting K-analog a pseudogap develops at frequencies of about 200 cm$^{-1}$ for temperatures T < 200 K. Based on exact diagonalisation calculations on an extended Hubbard model at quarter-filling we argue that fluctuati

A. Wahl, Ch. Simon, S. Mercone, D. Saurel

The electrical and magnetic response to a bias current has been investigated in a singlecrystalline ferromagnetic manganese oxide $\Pr_{0.8}$Ca$_{0.2}$MnO$_3$ . A significant decrease of the magnetization is observed at the same threshold current where a non-linearity of V-I characteristics appears. Such a behavior cannot be understood in the framework of th

W. Prellier, E. Rauwel Buzin, S. de Brion, G. Chouteau

We have investigated the magnetic-field-induced phase transition of charge-ordered (CO) Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ thin films, deposited onto (100)-oriented LaAlO$_3$ and (100)-oriented SrTiO$_3$ substrates using the pulsed laser deposition technique, by measuring the transport properties with magnetic fields up to 22T. The transition to a metallic state is

V. Grau, J. Boronat, J. Casulleras

The equation of state of two-dimensional $^3$He at zero temperature has been calculated using the diffusion Monte Carlo method. By means of a combination of the fixed-node and released-node techniques it is shown that backflow correlations provide a very accurate equation of state. The results prove unambiguously the non-self-bound character of two-dimension

Jurgen Horbach, Walter Kob

We use molecular dynamics computer simulations to study the relaxation dynamics of Na2O-2(SiO2) in its molten, highly viscous state. We find that at low temperatures the incoherent intermediate scattering function for Na relaxes about 100 times faster than the one of the Si and O atoms. In contrast to this all coherent functions relax on the same time scale

S. Ozcan, D. M. Broun, B. Morgan, R. K. W. Haselwimmer

We have made the first complete measurements of the London penetration depth $λ(T)$ of CeCoIn5, a quantum-critical metal where superconductivity arises from a non-Fermi-liquid normal state. Using a novel tunnel diode oscillator designed to avoid spurious contributions to $λ(T)$, we have established the existence of intrinsic and anomalous power-law behaviour

Maryam Rahimi, M. R. Sakr, S. V. Kravchenko, S. C. Dultz

We have measured compressibility of a two-dimensional hole gas in p-GaAs/AlGaAs heterostructure, grown on a (100) surface, in the presence of a tilted magnetic field. It turns out that the parallel component of magnetic field affects neither the spin splitting nor the density of states. We conclude that: (a) g-factor in the parallel magnetic field is nearly

Akihisa Koga, Yoshiki Imai, Norio Kawakami

Electron correlations in the two-orbital Hubbard model at half-filling are investigated by combining dynamical mean field theory with the exact diagonalization method. We systematically study how the interplay of the intra- and inter-band Coulomb interactions, together with the Hund coupling, affects the metal-insulator transition. It is found that if the in