January 2004 arXiv papers — page 9

D. Yvon, F. Mayet

A major goal of CMB experiments is to obtain highly sensitive CMB maps in order to extract Spherical Harmonic Power Spectrum (SHPS) and cosmological parameters with unprecedented accuracy. We present a new map-making code (Mirage), based on a two-phase iterative algorithm, involving low frequency drift treatment, Butterworth high-pass filtering and conjugate

Naoyuki Haba, Yutaka Hosotani, Yoshiharu Kawamura, Toshifumi Yamashita

We study the dynamical symmetry breaking in the gauge-Higgs unification of the 5D theory compactified on an orbifold, $S^1/Z_2$. This theory identifies Wilson line degrees of freedoms as ``Higgs doublets''. We consider $SU(3)_c \times SU(3)_W$ and SU(6) models with the compactification scale of order a few TeV. The gauge symmetries are reduced to $SU

D. F. Mota, C. van de Bruck

We study the spherical collapse model in dark energy cosmologies, in which dark energy is modelled as a minimally coupled scalar field. We first follow the standard assumption that dark energy does not cluster on the scales of interest. Investigating four different popular potentials in detail, we show that the predictions of the spherical collapse model dep

A. Cottet, W. Belzig

We investigate current fluctuations in a three-terminal quantum dot in the sequential tunneling regime. Dynamical spin blockade can be induced when the spin-degeneracy of the dot states is lifted by a magnetic field. This results in super-Poissonian shot noise and positive zero-frequency cross-correlations. Our proposed setup can be realized with semiconduct

Olivier Sigwarth, Guillaume Labeyrie, Thibaut Jonckheere, Dominique Delande

We study the effect of an external magnetic field on coherent backscattering of light from a cool rubidium vapor. We observe that the backscattering enhancement factor can be {\it increased} with $B$. This surprising behavior shows that the coherence length of the system can be increased by applying a magnetic field, in sharp contrast with ususal situations.

A. Ciaramella, C. Bongardo, H. D. Aller, M. F. Aller

We have carried out a multifrequency analysis of the radio variability of blazars, exploiting the data obtained during the extensive monitoring programs carried out at the University of Michigan Radio Astronomy Observatory (UMRAO, at 4.8, 8, and 14.5 GHz) and at the Metsahovi Radio Observatory (22 and 37 GHz). Two different techniques detect, in the Metsahov

S. Noll, D. Mehlert, I. Appenzeller, R. Bender

We present a catalogue and atlas of low-resolution spectra of a well defined sample of 341 objects in the FORS Deep Field. All spectra were obtained with the FORS instruments at the ESO VLT with essentially the same spectroscopic set-up. The observed extragalactic objects cover the redshift range 0.1 to 5.0. 98 objects are starburst galaxies and QSOs at z >

Daniele Binosi

The generalization of the pinch technique to all orders in the electroweak sector of the Standard Model within the class of the renormalizable 't Hooft gauges, is presented. In particular, both the all-order PT gauge-boson-- and scalar--fermions vertices, as well as the diagonal and mixed gauge-boson and scalar self-energies are explicitly constructed. T

I. F. Ginzburg, I. P. Ivanov

The study of charge asymmetry of pions in the high-energy process gamma p -> pi+ pi- p (e p -> e pi+ pi- p) at very small dipion momenta offers a method to measure the phase of the forward hadronic (quasi)elastic amplitude gamma p -> rho p. We estimate potential of such measurements at HERA.

Patrick Francois, Francesca Matteucci, Roger Cayrel, Monique Spite

We computed the evolution of the abundances of O, Mg, Si, Ca, K, Ti, Sc, Ni, Mn, Co, Fe and Zn in the Milky Way. We made use of the most widely adopted nucleosynthesis calculations and compared the model results with observational data with the aim of imposing constraints upon stellar yields. In order to fit at best the data in the solar neighborhood, when a

S. Serventi, G. Allodi, R. De Renzi, G. Guidi

We have measured the transverse field muon spin precession in the flux lattice (FL) state of the two gap superconductor MgB2 and of the electron doped compounds Mg1-xAlxB2 in magnetic fields up to 2.8T. We show the effect of the two gaps on the internal field distribution in the FL, from which we determine two coherence length parameters and the doping depen

S. De Leo, P. Rotelli

The radial equation of a simple potential model has long been known to yield an exponential decay law in lowest order (Breit-Wigner) approximation. We demonstrate that if the calculation is extended to fourth order the decay law exhibits the quantum Zeno effect. This model has further been studied numerically to characterize the extra exponential time parame

G. Ruocco, F. Sciortino, F. Zamponi, C. De Michele

The concept of fragility provides a possibility to rank different supercooled liquids on the basis of the temperature dependence of dynamic and/or thermodynamic quantities. We recall here the definitions of kinetic and thermodynamic fragility proposed in the last years and discuss their interrelations. At the same time we analyze some recently introduced mod

Cameron Wellard, Roman Orus

Motivated by its relation to an $\cal{NP}$-hard problem, we analyze the ground state properties of anti-ferromagnetic Ising-spin networks embedded on planar cubic lattices, under the action of homogeneous transverse and longitudinal magnetic fields. This model exhibits a quantum phase transition at critical values of the magnetic field, which can be identifi

J. Berges

A loop or coupling expansion of a so-called n-particle irreducible (nPI) generating functional provides a well-defined approximation scheme in terms of self-consistently dressed propagators and n-point vertices. A self-consistently complete description determines the functional for arbitrarily high n to a given order in the expansion. We point out an equival

B. Eynard, A. Kokotov, D. Korotkin

Using the loop equations we find an explicit expression for genus 1 correction in hermitian two-matrix model in terms of holomorphic objects associated to spectral curve arising in large N limit. Our result generalises known expression for $F^1$ in hermitian one-matrix model. We discuss the relationship between $F^1$, Bergmann tau-function on Hurwitz spaces,

Naoki Itoh, Ryohei Asahara, Nami Tomizawa, Shinya Wanajo

We calculate the ion-ion correlation effect on the neutrino-nucleus scattering in supernova cores, which is an important opacity source for the neutrinos and plays a vital role in the supernova explosion. In order to calculate the ion-ion correlation effect we use the results of the improved hypernetted-chain method calculations of the classical one-componen

Joel Gilmore, Ross H. McKenzie

We give a theoretical treatment of the interaction of electronic excitations (excitons) in biomolecules and quantum dots with the surrounding polar solvent. Significant quantum decoherence occurs due to the interaction of the electric dipole moment of the solute with the fluctuating electric dipole moments of the individual molecules in the solvent. We intro

L. Mathey, D. -W. Wang, W. Hofstetter, M. D. Lukin

We use bosonization approach to investigate quantum phases in mixtures of bosonic and fermionic atoms confined in one dimensional optical lattices. The phase diagrams can be well understood in terms of polarons, which correspond to atoms that are "dressed" by screening clouds of the other atom species. For a mixture of single species of fermionic and

A. R. P. Rau

The concept of supersymmetry in a quantum mechanical system is extended, permitting the recognition of many more supersymmetric systems, including very familiar ones such as the free particle. Its spectrum is shown to be supersymmetric, with space-time symmetries used for the explicit construction. No fermionic or Grassmann variables need to be invoked. Our

F. Benatti, R. Floreanini, M. Piani

We study dynamical semigroups of positive, but not completely positive maps on finite-dimensional bipartite systems and analyze properties of their generators in relation to non-decomposability and bound-entanglement. An example of non-decomposable semigroup leading to a 4x4-dimensional bound-entangled density matrix is explicitly obtained.

Jose M. Fernandez, Seth Lloyd, Tal Mor, Vwani Roychowdhury

An efficient technique to generate ensembles of spins that are highly polarized by external magnetic fields is the Holy Grail in Nuclear Magnetic Resonance (NMR) spectroscopy. Since spin-half nuclei have steady-state polarization biases that increase inversely with temperature, spins exhibiting high polarization biases are considered cool, even when their en

Christino Tamon, Tomoyuki Yamakami

This paper has been withdrawn by Christino Tamon and Tomoyuki Yamakami because of errors of the main theorems. An erratum appeared in the Proceedings of the UMC 2000 Conference published by Springer.

R. G. Khlebopros, V. A. Slepkov, V. G. Sukhovolsky, Y. V. Mironov

The problem of the onset and growth of solid tumour in homogeneous tissue is regarded using an approach based on local interaction between the tumoral and the sane tissue cells. The characteristic sizes and growth rates of spherical tumours, the points of the beginning and the end of spherical growth, and the further development of complex structures (elonga

Paul Smolen, Paul E. Hardin, Brian S. Lo, Douglas A. Baxter

A model of Drosophila circadian rhythm generation was developed to represent feedback loops based on transcriptional regulation of per, Clk (dclock), Pdp-1, and vri (vrille). The model postulates that histone acetylation kinetics make transcriptional activation a nonlinear function of [CLK]. Such a nonlinearity is essential to simulate robust circadian oscil

B. J. Powell, T. Baruah, N. Bernstein, K. Brake

We report first principles density functional calculations for hydroquinone (HQ), indolequinone (IQ) and semiquinone (SQ). These molecules are believed to be the basic building blocks of the eumelanins, a class of bio-macromolecules with important biological functions (including photoprotection) and with potential for certain bioengineering applications. We

Kostas Kordas, Saverio D'Auria, Andy Hocker, Susan McGimpsey

We present here the first direct and detailed measurements of the spatial distribution of the ionizing radiation surrounding a hadron collider experiment. Using data from two different exposures we measure the effect of additional shielding on the radiation field around the Collider Detector at Fermilab (CDF). Employing a simple model we parameterize the ion

S Sahoo, S C Mukherjee, H R J Walters

We study the ionization process involving antiproton and hydrogen in the energy range between 0.1 keV to 500 keV, using single center close coupling approximation. We construct the scattering wave function using B-spline bases. The results obtained for ionization of atomic hydrogen are compared with other existing theoretical calculations as well as with the

Tapani Stipa

The Eady problem of baroclinic instability as applicable to quasi-geostrophic oceanic flows with zero internal PV gradients is revisited by introducing a mild slope and Ekman pumping on the lower boundary. The solution behaviour is determined by the isopycnal slope relative to either the bottom slope or the ratio of Ekman depth to horizontal wavenumber. Atte

A. Niell, L. Petrov

The use of a Numerical Weather Model (NWM) to provide in situ atmosphere information for mapping functions of atmosphere delay has been evaluated using Very Long Baseline Interferometry (VLBI) data spanning eleven years. Parameters required by the IMF mapping functions (Niell 2000, 2001) have been calculated from the NWM of the National Centers for Environme

L. Petrov, J. -P. Boy

We have computed 3-D displacements induced by atmospheric pressure loading from 6-hourly surface pressure field from NCEP (National Center for Environmental Predictions) Reanalysis data for all Very Long Baseline Interferometry) and SLR (Satellite Laser Ranging) stations. We have quantitatively estimated the error budget our time series of pressure loading a

Eva Koscielny-Bunde, Jan W. Kantelhardt, Peter Braun, Armin Bunde

We study temporal correlations and multifractal properties of long river discharge records from 41 hydrological stations around the globe. To detect long-term correlations and multifractal behaviour in the presence of trends, we apply several recently developed methods [detrended fluctuation analysis (DFA), wavelet analysis, and multifractal DFA] that can sy

Stefano Mattiello

We present a relativistic three-body equation to study the stability of the isolated three-body system and the correlations in a medium of finite temperatures and densities. Relativity is implemented utilizing the light front form. Using a zero-range force we find the relativistic analog of the Thomas collapse and investigate the possibility that the nucleon

B. van den Brandt, H. W. Griesshammer, P. Hautle, J. Kohlbrecher

The understanding of few-nucleon systems at low energies is essential, e.g. for accurate predictions of element abundances in big-bang and stellar fusion. Novel effective field theories, taking only nucleons, or nucleons and pions as explicit degrees of freedom, provide a systematic approach, permitting an estimate of theoretical uncertainties. Basic constan

B. Bagchi, C. Quesne

We comment that the conditionally exactly solvable potential of Dutt et al. and the exactly solvable potential from which it is derived form a dual system.

Tom Halverson, Arun Ram

q-rook monoid algebras, Hecke algebras and Schur-Weyl duality

Edith Adan-Bante

Let $G$ be a finite $p$-group and $χ,ψ$ be irreducible characters of $G$. We study the character $χψ$ when $χψ$ has at most $p-1$ distinct irreducible constituents.

David Bessis

We construct a quasi-Garside monoid structure for the free group. This monoid should be thought of as a dual braid monoid for the free group, generalising the constructions by Birman-Ko-Lee and by the author of new Garside monoids for Artin groups of spherical type. Conjecturally, an analog construction should be available for arbitrary Artin groups and for

Persi Diaconis, Arun Ram

Analysis of systematic scan Metropolis algorithms using Iwahori-Hecke algebra techniques

Philippe Caldero, Frederic Chapoton, Ralf Schiffler

Cluster algebras were introduced by S. Fomin and A. Zelevinsky in connection with dual canonical bases. Let U be a cluster algebra of type A_n. We associate to each cluster C of U an abelian category Cat_C such that the indecomposable objects of Cat_C are in natural correspondence with the cluster variables of U which are not in C. We give an algebraic reali

Alexander V. Karzanov

A convex triangular grid is represented by a planar digraph $G$ embedded in the plane so that (a) each bounded face is surrounded by three edges and forms an equilateral triangle, and (b) the union $\Rscr$ of bounded faces is a convex polygon. A real-valued function $h$ on the edges of $G$ is called a concave cocirculation if $h(e)=g(v)-g(u)$ for each edge $

Peter Kropholler, Peter Linnell, Wolfgang Lueck

A group G has homological dimension less or equal to 1 if it is locally free. We prove the converse provided that G satisfies the Atiyah Conjecture about L^2-Betti numbers. We also show that a finitely generated elementary amenable group G of cohomological dimension less or equal to 2 possesses a finite 2-dimensional model for BG and in particular that G is

Richard Evan Schwartz

We say that a collection Gamma of geodesics in the hyperbolic plane H^2 is a modular pattern if Gamma is invariant under the modular group PSL_2(Z), if there are only finitely many PSL_2(Z)-equivalence classes of geodesics in Gamma, and if each geodesic in Gamma is stabilized by an infinite order subgroup of PSL_2(Z). For instance, any finite union of closed

Ilia Krasikov

We shall establish two-side explicit inequalities, which are asymptotically sharp up to a constant factor, on the maximum value of $|H_k(x)| e^{-x^2/2},$ on the real axis, where $H_k$ are the Hermite polynomials.

Gadde A. Swarup

We give an exposition of Delzant's ideas extending the notion of Scott complexity of finitely generated groups to surjective homomorphisms of finitely presented groups to finitely generated groups.

José Manuel Marco, Javier Parcet

In this paper we present a unified approach to the spectral analysis of an hypergeometric type operator whose eigenfunctions include the classical orthogonal polynomials. We write the eigenfunctions of this operator by means of a new Taylor formula for operators of Askey-Wilson type. This gives rise to some expressions for the eigenfunctions, which are unkno

Andrea Posilicano, Stefania Ugolini

We suggest a rigorous definition of the pathwise flux across the boundary of a bounded open set for transient finite energy diffusion processes. The expectation of such a flux has the property of depending only on the current velocity $v$, the nonsymmetric (as regards time reversibility) part of the drift. In the case the diffusion has a limiting velocity we

Vestislav Apostolov, David M. J. Calderbank, Paul Gauduchon

We introduce the notion of a hamiltonian 2-form on a Kaehler manifold and obtain a complete local classification. This notion appears to play a pivotal role in several aspects of Kaehler geometry. In particular, on any Kaehler manifold with co-closed Bochner tensor, the (suitably normalized) Ricci form is hamiltonian, and this leads to an explicit descriptio

Philip Foth, Guadalupe Lozano

We consider the moduli space M_r of polygons with fixed side lengths in five-dimensional eucledian space. We analyze the local structure of its singularities and exhibit a real-analytic equivalence between M_r and a weighted quotient of the n-fold product of the quaternionic projective line HP^1 by the diagonal PSL(2,H)-action. We explore the relation betwee

D. Bashkirov, G. Sardanshvily

We show that, in gauge theory of principal connections, any gauge non-invariant Lagrangian can be completed to the BRST-invariant one. The BRST extension of the global Chern-Simons Lagrangian is present.

M. T. Grisaru, S. Penati, A. Romagnoni

In these proceedings we review the main results concerning superspace geometries with nonanticommutative spinorial variables and field theories formulated on them. In particular, we report on the quantum properties of the WZ model formulated in the N=1/2 nonanticommutative superspace.

Iosif Bena, Douglas Smith

In this note we present several ideas toward the solution to the giant graviton puzzle - the apparent multiplicity of supergravity states dual to field theory chiral primary operators. We use the fact that, for certain ranges of the angular momentum, giant gravitons can be mapped into vacua of a dual theory to argue that the sphere and $AdS$ giant gravitons

Thomas Thiemann

We combine I. background independent Loop Quantum Gravity (LQG) quantization techniques, II. the mathematically rigorous framework of Algebraic Quantum Field Theory (AQFT) and III. the theory of integrable systems resulting in the invariant Pohlmeyer Charges in order to set up the general representation theory (superselection theory) for the closed bosonic q

Yu Jia

We employ the effective field theory method to systematically study the short-range interaction in two-body sector in 2, 3 and 4 spacetime dimensions, respectively. The phi**4 theory is taken as a specific example and matched onto the nonrelativistic effective theory to one loop level. An exact, Lorentz-invariant expression for the S-wave amplitude is presen

Yong-Wan Kim, Chang-Yeong Lee, Seung-Kook Kim, Young-Jai Park

In the symplectic Lagrangian framework we newly embed an irreducible massive vector-tensor theory into a gauge invariant system, which has become reducible, by extending the configuration space to include an additional pair of scalar and vector fields, which give the desired Wess-Zumino action. A comparision with the BFT Hamiltonian embedding approach is als

Varghese Mathai, Jonathan Rosenberg

It is known that the T-dual of a circle bundle with H-flux (given by a Neveu-Schwarz 3-form) is the T-dual circle bundle with dual H-flux. However, it is also known that torus bundles with H-flux do not necessarily have a T-dual which is a torus bundle. A big puzzle has been to explain these mysterious "missing T-duals.'' Here we show that this p

Pei-Ming Ho

Implications of the SL(2,R) symmetry of the c = 1 matrix models are explored. Based on the work of de Alfaro, Fubini and Furlan, we note that when the Fermi sea is drained, the matrix model for 2 dimensional string theory in the linear dilaton background is equivalent to the matrix model of AdS_2 recently proposed by Strominger, for which SL(2,R) is an isome

T. E. Clark, Muneto Nitta, T. ter Veldhuis

The Green-Schwarz action for a non-BPS p=2 brane embedded in a N=1, D=4 target superspace is shown to be equivalent to the Nambu-Goto-Akulov-Volkov action obtained via the nonlinear realization of the associated target space super-Poincare symmetries. Introducing a U(1) gauge field strength as a Lagrange multiplier, this p=2 brane action is re-cast into its

T. M. Aliev, A. Ozpineci, M. Savci

We calculate the form factors V, A_1, A_2 and A_0 appearing in the (D -> phi) transition in light cone QCD sum rule method. We compare our results on these form factors with the current experimental results and existing theoretical calculations.

V. V. Nesvizhevsky, K. V. Protasov

An upper limit to non-Newtonian attracive forces is obtained from the measurement of quantum states of neutrons in the Earth's gravitational field. This limit improves the existing constrains in the nanometer range.

J. D. Vergados

We briefly review some theoretical issues involved in the direct detection of supersymmetric (SUSY) dark matter. After a brief discussion of the allowed SYSY parameter space we focus on the determination of the traditional neutralino detection rates, in experiments which measure the energy of the recoiling nucleus, such as the coherent and spin induced rates

G. Soyez

In a previous paper, we have shown that it was possible to use the DGLAP evolution equatio n to constrain the high-$Q^2$ ($Q^2 \ge 10$ GeV$^2$) behaviour of the residues of a high-e nergy Regge model, and we applied the developed method to the triple-pole pomeron model. W e show here that one can obtain a description of the low-$Q^2$ $γ^{(*)} p$ data match i

M. S. Sozzi

We review different definitions of the $ε'$ parameter describing direct CP violation in neutral kaon decays, which was precisely measured in recent experiments, and point out the inconsistency of some of them due to a CPT constraint. The proper comparison of the experimental results to the theoretical computations is discussed.

Pedro Costa, M. C. Ruivo, Yu. L. Kalinovsky

The weak leptonic decays $π^\pm\toμ^\pmν_μ(\barν_μ), π^\pm\to e^\pmν_e(\barν_{e}), K^\pm\toμ^\pmν_μ(\barν_μ)$ and $K^\pm\to e^\pm ν_e(\barν_{e})$ are investigated within the framework of the SU(3) Nambu-Jona-Lasinio model, in the vacuum and in quark matter in $β$ equilibrium. It is found that, at low densities, the decay rates of the charge multiplets, that

A. E. Dorokhov

The topological susceptibility of QCD vacuum is studied in the framework of a covariant chiral quark model with non-local quark-quark interaction. The relation of the first moment of topological susceptibility χ'(0) and the 'spin crisis' problem is briefly discussed. It is shown, in particular, that one always gets the inequality χ'(0)>χ'

V. Cirigliano, H. Neufeld, H. Pichl

We present a detailed numerical study of the K_{e3} decays to O(p^6,(m_d-m_u)p^2,e^2p^2) in chiral perturbation theory with virtual photons and leptons. We describe the extraction of the CKM matrix element |V_{us}| from the experimental K_{e3} decay parameters. We propose a consistency check of the K^+_{e3} and K^0_{e3} data that is largely insensitive to th

R. Bijker, M. M. Giannini, E. Santopinto

We discuss the spectroscopy of pentaquarks. The quantum numbers of the ground state depend on the interplay between spin-flavor and orbital contributions to the energy. The magnetic moments of the lowest pentaquark state with negative and positive parity are found to be 0.382 μ_N and 0.089 μ_n, respectively.

Ralf Hofmann

We review the status of the practical operator product expansion (OPE), when applied to two-point correlators of QCD currents which interpolate to mesonic resonances, in view of the violations of local quark-hadron duality. Covered topics are: a mini-review of mesonic QCD sum rules in vacuum, at finite temperature, or at finite baryon density, a comparison o

Dan Green

At the LHC the resolution of dijet mass is compromised by the pile up of energy from overlapping minimum bias events. Using anxillary measurements of the jet mass and the energy in distant cones, the resolution can be improved, as illustrated by a study of Z' of 120 GeV mass with the LHC operating at design luminosity.

The BABAR Collaboration, B. Aubert

We study B^+/- --> J/psi pi^+/- and B^+/- --> J/psi K^+/- decays in a sample of about 89 million BB~ pairs collected with the BABAR detector at the PEP-II asymmetric B-factory at SLAC. We observe a signal of 244 +/- 20 B^+/- --> J/psi pi^+/- events and determine the ratio BF(B^+/- --> J/psi pi^+/-)/BF(B^+/- --> J/psi K^+/-) to be [5.37 +/- 0.45 (stat.) +/- 0

Lee C. Loveridge

Various interpretations of the Riemann Curvature Tensor, Ricci Tensor, and Scalar Curvature are described. Also, the physical meanings of the Einstein Tensor and Einstein's Equations are discussed. Finally a derivation of Newtonian Gravity from Einstein's Equations is given.

Enrique Alvarez

Some kinematical speculations on the infinite curvature limit of the conjectured duality of Maldacena between ten-dimensional strings living in $AdS_5\times S_5$ and a ordinary four-dimensional quantum field theory, namely ${\cal{N}}=4$ super Yang-Mills with gauge group SU(N) are given.

Toby Ord, Tien D. Kieu

While it is well known that a Turing machine equipped with the ability to flip a fair coin cannot compute more that a standard Turing machine, we show that this is not true for a biased coin. Indeed, any oracle set $X$ may be coded as a probability $p_{X}$ such that if a Turing machine is given a coin which lands heads with probability $p_{X}$ it can compute

A. I. D'yachenko, V. Yu. Tarenkov, M. A. Belogolovskii, V. N. Varyukhin

We report on tunneling and Andreev-reflection conductance spectra of 39 K superconducting magnesium diboride, obtained with Pb and Au counter-electrodes. Two distinct steps at close to 2.7 and 7.1 meV appear in a low-resistance metallic-type Au-MgB2 junction characteristic, whereas a tunneling-like spectrum measured for the same junction, annealed by the app

A. W. Sandvik, L. Balents, D. K. Campbell

Using quantum Monte Carlo simulations, results of a strong-coupling expansion, and Luttinger liquid theory, we determine quantitatively the ground state phase diagram of the one-dimensional extended Hubbard model with on-site and nearest-neighbor repulsions U and V. We show that spin frustration stabilizes a bond-ordered (dimerized) state for U appr. V/2 up

Dirk Helbing

The transport of products between different suppliers or production units can be described similarly to driven many-particle and traffic systems. We introduce equations for the flow of goods in supply networks and the adaptation of production speeds. Moreover, we present two examples: The case of linear (sequential) supply chains and the case of re-entrant p

N. K. Kuzmenko, V. M. Mikhajlov

Oscillating behaviour of the susceptibility and heat capacity is considered for normal and superconducting mesoscopic systems (nanoclusters and quantum dots). It is proved that at low temperature an increasing magnetic field applied to a mesoscopic system generates local extrema of the susceptibility and heat capacity. A maximum for the susceptibility and a

R. A. Trasca, N. Ferralis, R. D. Diehl, M. W. Cole

An interaction potential energy between and adsorbate (Xe and Ar) and the 10-fold Al-Ni-Co quasicrystal is computed by summing over all adsorbate-substrate interatomic interactions. The quasicrystal atoms' coordinates are obtained from LEED experiments and the Lennard-Jones parameters of Xe-Al, Xe-Ni and Xe-Co are found using semiempirical combining rule

D. Dimitrov, V. Lovchinov, M. Gospodionov, with Ph. Vanderbemden

Measurements of DC magnetization, AC susceptibility and Hall effect of $Pr_{0.7}Sr_{0.3}MnO_3$ single crystal are reported. The various features are discussed in terms of competing electronic and spin ordering phase transitions, in particular concerning the $e_g$ and $t_{2g}$ competition and its effect on spin ordering.

C. Amoruso, A. K. Hartmann

We study ground-state properties of the two-dimensional random-bond Ising model with couplings having a concentration $p\in[0,1]$ of antiferromagnetic and $(1-p)$ of ferromagnetic bonds. We apply an exact matching algorithm which enables us the study of systems with linear dimension $L$ up to 700. We study the behavior of the domain-wall energies and of the

E. D. Bauer, A. D. Christianson, J. M. Lawrence, E. A. Goremychkin

The crystalline electric field (CEF) energy level scheme of the heavy fermion superconductor CeCoIn_5 has been determined by means of inelastic neutron scattering (INS). Peaks observed in the INS spectra at 8 meV and 27 meV with incident neutron energies between E_i=30-60 meV and at a temperature T = 10 K correspond to transitions from the ground state to th

R. M. Lewis, Yong Chen, L. W. Engel, D. C. Tsui

For filling factors $ν$ in the range between 4.16 and 4.28, we simultaneously detect {\it two} resonances in the real diagonal microwave conductivity of a two--dimensional electron system (2DES) at low temperature $T \approx 35$ mK. We attribute the resonances to Wigner crystal and Bubble phases of the 2DES in higher Landau Levels. For $ν$ below and above th

A. Rákos, G. M. Schütz

We study driven 1d lattice gas models with two types of particles and nearest neighbor hopping. We find the most general case when there is a shock solution with a product measure which has a density-profile of a step function for both densities. The position of the shock performs a biased random walk. We calculate the microscopic hopping rates of the shock.

Violeta Gotcheva, Albert T. J. Wang, S. Teitel

A continuous time Monte Carlo lattice gas dynamics is developed to model driven steady states of vortices in two dimensional superconducting networks. Dramatic differences are found when compared to a simpler Metropolis dynamics. Subtle finite size effects are found at low temperature, with a moving smectic that becomes unstable to an anisotropic liquid on s

J. Spitaler, E. Ya. Sherman, C. Ambrosch-Draxl, H. - G. Evertz

We investigate electronic and optical properties of the V-based ladder compounds NaV2O5, the iso-structural CaV2O5, as well as MgV2O5, which differs from NaV2O5 and CaV2O5 in the c axis stacking. We calculate ab initio the A_g phonon modes in these compounds as a basis for the investigation of the electron-phonon and spin-phonon coupling. The phonon modes to

V. Ricardo Paredes, Ana I. Fariñas-Sánchez, Bertrand Berche

By means of Monte Carlo simulations, using finite size scaling and conformal transformations, evidences of a topological phase transition in liquid crystals in two dimensions are reported. A paramagnetic phase appears at high temperature whereas a quasi-long-range-order (QLRO) phase is founded at low temperatures. It is determined that the correlation functi

M. I. Katsnelson, A. V. Trefilov

Slow dynamics of energy transfer between different phonon modes under the resonance conditions is considered. It may result in new effects in the inelastic and quasielastic neutron scattering spectra.

I. Puica, W. Lang, W. Goeb, R. Sobolewski

Measurements of the Hall effect and the resistivity on precisely-patterned YBCO thin films in magnetic fields B from 0.5 to 6 T oriented parallel to the sample crystallographic c axis reveal a sign reversal of the Hall coefficient for B <= 3 T. The data are compared to the full, quantitative expressions based on the renormalized fluctuation model for the Hal

Rauno Buescher, Thorsten Emig

Due to their collective nature Casimir forces can strongly depend on the geometrical shape of the interacting objects. We study the effect of strong periodic shape deformations of two ideal metal plates on their quantum interaction. A non-perturbative approach which is based on a path integral quantization of the electromagnetic field is presented in detail.

G. Parisi, G. Ruocco, F. Zamponi

We investigate the relation between fragility and phase space properties - such as the distribution of states - in the mean field p-spin model, a solvable model that has been frequently used in studies of the glass transition. By direct computation of all the relevant quantities, we find that: i) the recently observed correlation between fragility and vibrat

S. Tajima, Y. Fudamoto, T. Kakeshita, B. Gorshunov

Temperature dependences of the optical spectra of La$_{2-x}$Sr$_x$CuO$_4$ with $x$=0.12 and 0.15 were carefully examined for a polarization parallel to the CuO$_2$-plane over a wide frequency range down to 8 cm$^{-1}$. Selection of well-characterized crystals enabled us to measure purely in-plane polarized spectra without any additional peak. The weight of s

Sei Suzuki, Tatsuya Nakajima

The quantum Monte-Carlo method is applied to two-dimensional electron systems under strong magnetic fields. The negative-sign problem involved by this method can be avoided for certain filling factors by modifying interaction parameters from those of the Coulomb interaction. Our techniques for obtaining sign-problem-free parameters are described in detail. C

T. Di Matteo, M. Airoldi, E. Scalas

At present, there is an explosion of practical interest in the pricing of interest rate (IR) derivatives. Textbook pricing methods do not take into account the leptokurticity of the underlying IR process. In this paper, such a leptokurtic behaviour is illustrated using LIBOR data, and a possible martingale pricing scheme is discussed.

T. Di Matteo, T. Aste, R. N. Mantegna

An empirical analysis of interest rates in money and capital markets is performed. We investigate a set of 34 different weekly interest rate time series during a time period of 16 years between 1982 and 1997. Our study is focused on the collective behavior of the stochastic fluctuations of these time-series which is investigated by using a clustering linkage

T. M. Stace, C. H. W. Barnes, G. J. Milburn

We show that the one-way channel formalism of quantum optics has a physical realisation in electronic systems. In particular, we show that magnetic edge states form unidirectional quantum channels capable of coherently transporting electronic quantum information. Using the equivalence between one-way photonic channels and magnetic edge states, we adapt a pro

R. Mélin

The aim of this paper is to explain the non monotonic temperature dependence of the self-consistent superconducting gap of ferromagnet/superconductor/ferromagnet (F/S/F) trilayers with weak ferromagnets in the parallel alignment (equivalent to F/S bilayers). We show that this is due to Andreev bound states that compete with the formation of a minigap. Using

Werner Ebeling, Frank Schweitzer

After summarizing basic features of self-organization such as entropy export, feedbacks and nonlinear dynamics, we discuss several examples in biology. The main part of the paper is devoted to a model of active Brownian motion that allows a stochastic description of the active motion of biological entities based on energy consumption and conversion. This mod

Makoto Homma, Chigak Itoi

We construct a set of exact ground states with a localized ferromagnetic domain wall and an extended spiral structure in a deformed flat-band Hubbard model. In the case of quarter filling, we show the uniqueness of the ground state with a fixed magnetization. We discuss more realistic situation given by a band-bending perturbation, which can stabilize these

J. Marti, J. M. Paredes, J. S. Bloom, J. Casares

We report optical spectroscopic observations of a sample of 6 low-galactic latitude microquasar candidates selected by cross-identification of X-ray and radio point source catalogs for |b|<5 degrees. Two objects resulted to be of clear extragalactic origin, as an obvious cosmologic redshift has been measured from their emission lines. For the rest, none exhi

Pier Stefano Corasaniti

In this thesis we study some observational consequences of dark energy dominated cosmologies. After reviewing the main characteristics of quintessential models of dark energy, by using the SN Ia data and the position of the CMB peaks we constrain a class of parameterized scalar field potentials. Going beyond constraining specific classes models, we introduce