March 1999 arXiv papers — page 22

Yasufumi Kojima, Masayasu Hosonuma

The axial mode oscillations are examined for relativistic rotating stars with uniform angular velocity. Using the slow rotation formalism and the Cowling approximation, we have derived the equations governing the r-mode oscillations up to the second order with respect to the rotation. In the lowest order, the allowed range of the frequencies is determined, b

Gerhardt R. Meurer, Timothy M. Heckman, Daniela Calzetti

We refine a technique to measure the absorption corrected ultraviolet (UV) luminosity of starburst galaxies using rest frame UV quantities alone, and apply it to U-dropouts at z ~ 3 found in the Hubble Deep Field. The method is based on an observed correlation between the ratio of far infrared (FIR) to UV fluxes with spectral slope β(a UV color). A simple fi

Michael W. Regan, John S. Mulchaey

If AGN are powered by the accretion of matter onto massive black holes, how does the gas in the host galaxy lose the required angular momentum to approach the black hole? Gas easily transfers angular momentum to stars in strong bars, making them likely candidates. Although ground-based searches for bars in active galaxies using both optical and near infrared

Timothy M. Heckman

I will try to put the ultraluminous galaxy phenomenon into a broad cosmological context. Viewed from this perspective, the significance of ultraluminous galaxies and the `starburst vs. monster' debate becomes clear. Ultraluminous galaxies are fascinating in their own right, allow detailed study of the processes by which massive spheroids were built and t

M. J. Drinkwater, D. Proust, Q. A. Parker, H. Quintana

We present new radial velocities for 306 bright (R<16) galaxies in a 77 square deg region of the Shapley supercluster measured with the FLAIR-II spectrograph on the UK Schmidt Telescope. The galaxies we measured were uniformly distributed over the survey area in contrast to previous samples which were concentrated in several rich Abell clusters. Most of the

L. Toffolatti, G. De Zotti, F. Argüeso, C. Burigana

Confusion noise due to extragalactic sources is a fundamental astrophysical limitation for experiments aimed at accurately determining the power spectrum of the Cosmic Microwave Background (CMB) down to arcmin angular scales and with a sensitivity $ΔT/T \simeq 10^{-6}$. At frequencies $\lsim 200-300$ GHz, the most relevant extragalactic foreground hampering

J. Ricardo G. de Mendonça, Mário J. de Oliveira

We show that it is possible to derive the stationary coverage of an adsorption-desorption process of dimers with diffusional relaxation with a very simple ansatz for the stationary distribution of the process supplemented by a hypothesis of global balance. Our approach is contrasted to the exact result and we seek to understand its validity within an instanc

J. G. Bartlett, M. Douspis, A. Blanchard, M. Le Dour

Band-power estimates of cosmic microwave background fluctuations are now routinely used to place constraints on cosmological parameters. For this to be done in a rigorous fashion, the full likelihood function of band-power estimates must be employed. Even for Gaussian theories, this likelihood function is not itself Gaussian, for the simple reason that band-

Y. -Y. Keum, U. Nierste, A. I. Sanda

We analyze the theoretical implications of the new KTeV measurement of direct CP-violation in K->pi pi decays. The result is found consistent with the Standard Model for low values of the strange quark mass m_s. If the hadronic parameters B_6^{(1/2)} and B_8^{(3/2)} satisfy 2 B_6^{(1/2)} - B_8^{(3/2)} < 2, as suggested by lattice and 1/N_c calculations, we f

Robert de Mello Koch, Alastair Paulin-Campbell, Joao P. Rodrigues

We construct solutions of type IIB supergravity dual to N=2 super Yang-Mills theories. By considering a probe moving in a background with constant coupling and an AdS_{5} component in its geometry, we are able to reproduce the exact low energy effective action for the theory with gauge group SU(2) and N_{f}=4 massless flavors. After turning on a mass for the

Shahar Hod

Recently, we derived an improved universal upper bound to the entropy of a charged system $S \leq π(2E b-q^2)/ \hbar$. There was, however, some uncertainty in the value of the numerical factor which multiplies the $q^2$ term. In this paper we remove this uncertainty; we rederive this upper bound from an application of the generalized second law of thermodyna

I. P. Ivanov, N. N. Nikolaev, A. V. Pronyaev, W. Schäfer

We derive a unitarity relationship between the spin structure function $g_{LT}(x,Q^{2})=g_{1}(x,Q^{2})+g_{2}(x,Q^{2})$, the LT interference diffractive structure function and the spin-flip coupling of the pomeron to nucleons. Our diffractive mechanism gives rise to a dramatic small-$x$ rise $g_{LT}(x,Q^{2}) \sim g^{2}(x,\bar{Q}^{2}) \sim (1/x)^{2(1+δ_{g})}$,

A. Liccardo, F. Pezzella, R. Marotta

We give a construction of off-shell tree bosonic string amplitudes, based on the operatorial formalism of the $N$-string Vertex, with three external massless states both for open and closed strings by requiring their being projective invariant. In particular our prescription leads, in the low-energy limit, to the three-gluon amplitude in the usual covariant

L. Girardello, M. Petrini, M. Porrati, A. Zaffaroni

We discuss a solution of the equations of motion of five-dimensional gauged type IIB supergravity that describes confining SU(N) gauge theories at large N and large 't Hooft parameter. We prove confinement by computing the Wilson loop, and we show that our solution is generic, independent of most of the details of the theory. In particular, the Einstein-fram

Paul M. N. Feehan

We show that harmonic spinors obey a strengthened version of the well-known pointwise Kato inequality for sections of a vector bundle with a connection. We then prove a decay estimate for eigenspinors using this Kato-Yau estimate and resulting differential inequality. We briefly describe some applications to gauge theory---specifically to integral estimates

Yan V. Fyodorov, B. A. Khoruzhenko

We solve the problem of resonance statistics in systems with broken time-reversal invariance by deriving the joint probability density of all resonances in the framework of a random matrix approach and calculating explicitly all n-point correlation functions in the complex plane. As a by-product, we establish the Ginibre-like statistics of resonances for man

Giovanna Pugliese, Heino Falcke, Peter L. Biermann

We consider a jet-disk symbiosis model to explain Gamma Ray Bursts and their afterglows. It is proposed that GRBs develop in a pre-existing jet. We consider a binary system formed by a neutron star and an O/B/WR companion in which the energy of the GRB is due to the accretion-induced collapse of the neutron star to a black hole. The high speed in the energy

Ralf Aurich

The fluctuations of the cosmic microwave background (CMB) are investigated for a small open universe, i.e., one which is periodically composed of a small fundamental cell. The evolution of initial metric perturbations is computed using the first 749 eigenmodes of the fundamental cell in the framework of linear perturbation theory using a mixture of radiation

Yuji Okawa

The one-loop effective action for general trajectories of D-particles in Matrix theory is calculated in the expansion with respect to the number of derivatives up to six, which gives the equation of motion consistently. The result shows that the terms with six derivatives vanish for straight-line trajectories, however, they do not vanish in general. This pro

E. R. Bezerra de Mello, V. B. Bezerra, N. R. Khusnutdinov

We calculate the renormalized vacuum average of the energy-momentum tensor of massless left-handed spinor field in the pointlike global monopole spacetime using point-separation approach. The general structure of the vacuum average of the energy-momentum tensor is obtained and expressed in terms of $<T^0_0>^{ren}$ component, explicit form of which is analyze

Ch. Charitos, G. Tsapogas

If X is a proper CAT(-1)-space and $\Gamma$ a non-elementary discrete group of isometries acting properly discontinuously on X, it is shown that the geodesic flow on the quotient space Y=X/$\Gamma$ is topologically mixing, provided that the generalized Busemann function has zeros on the boundary $\partial X$ and the non-wandering set of the flow equals the w

Rong-Gen Cai, Dahl Park, Kwang-Sup Soh

In the microcanonical ensemble for string theory on $ AdS_m \times S^n$, there is a phase transition between a black hole solution extended over the $S^n$ and a solution localized on the $S^n$ if the $AdS_m$ has the topology $R^2 \times S^{m-2}$. The phase transition will not appear if the $AdS_m$ has the topology $R^2 \times T^{m-2}$, that is, when the $AdS

Shigeki Onoda, Masatoshi Imada

Pseudogap phenomena of high-T_c cuprates are examined. In terms of AFM (antiferromagnetic) and dSC (d_{x^2-y^2}-wave superconducting) auxiliary fields introduced to integrate out the fermions, the effective action for 2D electron systems with AFM and dSC fluctuations is considered. By the self-consistent renormalization (SCR), the NMR relaxation rate T_1^{-1

Kazuya Koyama, Jiro Soda, Atsushi Taruya

We consider constraints on the structure formation model based on non-Gaussian fluctuations generated during inflation, which have $χ_m^2$ distributions. Using three data sets, the abundance of the clusters at $z=0$, moderate $z$ and the correlation length, we show that constraints on the non-Gaussianity and the amplitude of fluctuations and the density para

N. F. Nasrallah

A QCD sum rule calculation of Balistky and Ji on the spin content of the nucleon is done with a different approach to the evaluation of the bilocal contributions and to the extraction of the nucleon pole residues. The result obtained is much more numerically stable which puts their conclusion that about half of the nucleon spin is carried by gluons on firmer

Ken Machida, Hiromichi Nakazato, Saverio Pascazio, Helmut Rauch

The dynamics of a quantum system undergoing frequent &#34;measurements&#34;, leading to the so-called quantum Zeno effect, is examined on the basis of a neutron-spin experiment recently proposed for its demonstration. When the spatial degrees of freedom are duely taken into account, neutron-reflection effects become very important and may lead to an evolutio

Yuri I. Manin

This is an expository talk written for the Bourbaki Seminar. After a brief introduction, Section 1 discusses in the categorical language the structure of the classical deterministic computations. Basic notions of complexity icluding the P/NP problem are reviewed. Section 2 introduces the notion of quantum parallelism and explains the main issues of quantum c

Jos Uffink

A new type of procedures, called protective measurements, has been proposed by Aharonov, Anandan and Vaidman. These authors argue that a protective measurement allows the determination of arbitrary observables of a single quantum system and claim that this favors a realistic interpretation of the quantum state. This paper proves that only observables that co

Fedor Herbut

Interference comes from coherent mixing. It can be suppressed by entanglement, and the latter can be erased so as to revive interference. If the entanglement is a mimal-term one (with minimal-term mixing), as is the case in most thought and real experiments reported, there appears the possibility of counter erasure and counter interference. This peculiar phe

T. C. Ralph, R. E. S. Polkinghorne, P. K. Lam

We discuss the characterization of continuous variable, optical quantum teleportation in terms of the two quadrature signal transfer and conditional variances between the input and output states. We derive criteria which clearly define the classical limits and highlight interesting operating points which are not obvious from a calculation of the fidelity of

Pawel Horodecki, Michal Horodecki, Ryszard Horodecki

We prove a theorem on direct relation between the optimal fidelity $f_{max}$ of teleportation and the maximal singlet fraction $F_{max}$ attainable by means of trace-preserving LQCC action (local quantum and classical communication). For a given bipartite state acting on $C^d\otimes C^d$ we have $f_{max}= {F_{max}d+1\over d+1}$. We assume completely general

M. L. Gorodetsky, V. S. Ilchenko, A. D. Pryamikov

Accurate calculation of internal and surface scattering losses in fused silica microspheres is done. We show that in microspheres internal scattering is partly inhibited as compared to losses in the bulk material. We pay attention on the effect of frozen thermodynamical capillary waves on surface roughness. We calculate also the value of mode splitting due t

S. G. Porsev, Yu. G. Rakhlina, M. G. Kozlov

The results of ab initio calculation of E1 amplitudes, lifetimes,and polarizabilities for several low-lying levels of ytterbium are reported. The effective Hamiltonian for the valence electrons has been constructed in the frame of CI+MBPT method and solutions of many electron equation are found.

X. Artru, R. Chehab, K. Honkavaara, A. Variola

The interest in using optical transition radiation (OTR) in high energy (multiGeV) beam diagnostics has motivated theoretical and experimental investigations on the limitations brought by diffraction on the attainable resolution. This paper presents calculations of the diffraction effects in an optical set-up using OTR. The OTR diffraction pattern in a teles

V. Koch

In this contribution we will discuss the production of low mass dileptons in SPS-energy heavy ion collisions. We briefly review the current theoretical situation before we turn to the analysis of the recent data for Pb+Au. We also will discuss the role of baryons as a source for dileptons.

S. Das Gupta, A. Majumder, S. Pratt, A. Mekjian

The statistical model of Chase and Mekjian, which offers an analytic solution for the canonical ensemble of non-interacting fragments, is investigated for it&#39;s thermodynamic behavior. Various properties of the model, which exhibits a first-order phase transition, are studied. The effects of finite particle number are investigated. Three extensions of the

Scott Pratt, Subal Das Gupta

A method is presented that allows exact calculations of fragment multiplicity distributions for a canonical ensemble of non-interacting clusters. Fragmentation properties are shown to depend on only a few parameters. Fragments are shown to be copiously produced above the transition temperature. At this transition temperature, the calculated multiplicity dist

K. Gudima, M. Ploszajczak

We report on the study of extremely high energy photons, pions and etas, produced in intermediate energy heavy-ion collisions. Possibility of imaging the final-state phase space in these collisions by the Bose-Einstein correlations for photons is critically examined.

E. Garrido, D. V. Fedorov, A. S. Jensen

We compare the properties of three-body systems obtained with two-body potentials with Pauli forbidden states and with the corresponding phase equivalent two-body potentials. In the first case the forbidden states are explicitly excluded in the calculation. Differences arise due to the off-shell properties of these on-shell equivalent potentials. We use the

Sergei B. Leble, A. A. Zaitsev

The problem of a differential operator left- and right division is solved in terms of generalized Bell polinomials for nonabelian differential unitary ring. The definition of the polinomials is made by means of recurrent relations. The expresions of classic Bell polinomils via generalized one is given. The conditions of an exact factorization possibility lea

Huai-Dong Cao, Jian Zhou

For a closed Kähler manifold with a Hamiltonian action of a connected compact Lie group by holomorphic isometries, we construct a formal Frobenius manifold structure on the equivariant cohomology by exploiting a natural DGBV algebra structure on the Cartan model.

Alexander Reznikov

We prove the Carlson-Toledo conjecture (for all Kahler groups which do not have property T of Kazhdan).We deduce a conjecture of Goldman-Donaldson for all 3-manifold groups which are rich in the sense of [Re2].

Felipe M. Pait, Paulo A Atkinson

We propose a tuner, suitable for adaptive control and (in its discrete-time version) adaptive filtering applications, that sets the second derivative of the parameter estimates rather than the first derivative as is done in the overwhelming majority of the literature. Comparative stability and performance analyses are presented.

Theresia Eisenkölbl

We prove a partition identity conjectured by Lassalle (Adv. in Appl. Math. 21 (1998), 457-472).

O. Schiffmann, E. Vasserot

We prove that the global base of the modified quantum algebra of affine GL_N is compatible with the intersection cohomology base of the convolution algebra of the affine flag variety. As a consequence we prove a recent conjecture of Lusztig on the compatibility of the intersection cohomology base with respect to transfer maps.

A. Stoimenow

We give examples showing that Kidwell&#39;s inequality for the maximal degree of the Brandt-Lickorish-Millett-Ho polynomial is in general not sharp.

Sergio Albeverio, Shao-Ming Fei

A study of symplectic forms associated with two dimensional quantum planes and the quantum sphere in a three dimensional orthogonal quantum plane is provided. The associated Hamiltonian vector fields and Poissonian algebraic relations are made explicit.

Carlos Simpson

We look more closely at the higher nonabelian de Rham cohomology of a smooth projective variety or family of varieties that had been defined in some previous papers. We formalize using $n$-stacks the notion of shape underlying this nonabelian cohomology. A generalization of the de Rham construction to any appropriate formal category or family of formal categ

M. Kapranov, E. Vasserot

We describe the derived category of coherent sheaves on the minimal resolution of the Kleinian singularity associated to a finite subgroup G of SL(2). Then, we give an application to the Euler-characteristic version of the Hall algebra of the category of coherent sheaves on an algebraic surface.

Pavel Etingof, Alexandre Soloviev

In this note we define geometric classical r-matrices and quantum R-matrices, and show how any geometric classical r-matrix can be quantized to a geometric quantum R-matrix. This is one of the simplest nontrivial examples of quantization of solutions of the classical Yang-Baxter equation, which can be explicitly computed.

Michael R. Douglas, Bartomeu Fiol

We derive D-brane gauge theories for C^3/Z_n x Z_n orbifolds with discrete torsion and study the moduli space of a D-brane at a point. We show that, as suggested in previous work, closed string moduli do not fully resolve the singularity, but the resulting space -- containing n-1 conifold singularities -- is somewhat surprising. Fractional branes also have u

Yuri Makeenko

The interaction between static D0-branes at finite temperature is considered in the matrix theory and the superstring theory. The results agree in both cases to the leading order in the supersymmetry violation by temperature, where the one-loop approximation is reliable. The effective static potential is short-ranged and attractive. Talk at the 32nd Internat

Michael Faux, Dieter Luest, Burt A. Ovrut

A systematic program is developed for analyzing and cancelling local anomalies on networks of intersecting orbifold planes in the context of M-theory. Through a delicate balance of factors, it is discovered that local anomaly matching on the lower-dimensional intersection of two orbifold planes may require twisted matter on those planes which do not conventi

I. L. Buchbinder

We consider N=4 supersymmetric Yang-Mills theory formulated in terms of N=2 superfields in harmonic superspace. Using the background field method we define manifestly gauge invariant and N=2 supersymmetric effective action depending on N=2 strength superfields and develop a general procedure for its calculation in one-loop approximation. Explicit form for th

Seungjoon Hyun, Youngjai Kiem, Hyeonjoon Shin

Via supersymmetry argument, we determine the effective action of the SU(2) supersymmetric Yang-Mills quantum mechanics up to two constants, which results from the full supersymmetric completion of the F^4 term. The effective action, consisting of zero, two, four, six and eight fermion terms, agrees with the known perturbative one-loop calculations from the t

Zachary Guralnik

We argue that non-supersymmetric large N QCD compactified on T^2 exhibits properties characteristic of an SL(2,Z) T-duality. The kahler structure on which this SL(2,Z) acts is given by $m/N + iΛ^2 A$, where A is the area of the torus, m is the &#39;t Hooft magnetic flux on the torus, and $Λ^2$ is the QCD string tension.

E. Sezgin, P. Sundell

We review the basic structure of the higher spin extension of D=4, N=8 AdS supergravity. The theory is obtained by gauging the higher spin superalgebra shs^E(8|4) by a procedure pioneered by Vasiliev. The algebra shs^E(8|4) is a subalgebra of the enveloping algebra of OSp(8|4). The physical states of the theory are in one to one correspondence with the symme

J. I. Kapusta, S. M. H. Wong

The bremsstrahlung produced when heavy nuclei collide is estimated for central collisions at the Relativistic Heavy Ion Collider. Bremsstrahlung photons with energies below 100 to 200 MeV are sufficient to discern the gross features of the space-time evolution of electric charge, if they can be separated from other sources of photons experimentally. This is

J. L. Lucio Martinez, M. Napsuciale Mendivil

We work out the Linear Sigma Model (LSM) predictions for the 2 gamma decay rates of the a_0(980),f_0(980) mesons under the assumption that they are respectively the I=1 and I=0 members of the bar q q scalar nonet. Agreement with experimental data is achieved provided we include the contribution of a κmeson with mass approx. 900 MeV, and a scalar mixing angle

Peter Lichard

We investigate the relations between the K_{l3} and tau --> K pi nu_tau decays using the meson dominance approach. First, the experimental branching fractions (BF) for K^-_{e3} and K^0_{e3} are used to fix two normalization constants (isospin invariance is not assumed). Then, the BF of tau^- --> K^*(892)^- nu_tau is calculated in agreement with experiment. W

G. Alexanian, E. F. Moreno, V. P. Nair, R. Ray

The hard thermal loop effective action for Goldstone bosons is deduced by symmetry arguments from the corresponding result for gauge bosons. Pseudoscalar mesons in Chromodynamics and magnons in an antiferromagnet are discussed as special cases, including the hard thermal loop contribution to their scattering.

S. Parke, S. Veseli

The production of a Higgs boson in association with a W-boson is the most likely process for the discovery of a light Higgs at the Fermilab Tevatron. Since it decays primarily to b-quark pairs, the principal background for this associated Higgs production process is WBBbar, where the BBbar pair comes from the splitting of an off mass shell gluon. In this pap

A. Djouadi, W. Kilian, M. Muhlleitner, P. M. Zerwas

To establish the Higgs mechanism sui generis experimentally, the self-energy potential of the Higgs field must be reconstructed. This task requires the measurement of the trilinear and quadrilinear self-couplings, as predicted, for instance, in the Standard Model or in supersymmetric theories. The couplings can be probed in multiple Higgs production at high-

D. Comelli, D. Grasso, M. Pietroni, A. Riotto

The presence of a primordial magnetic field in the early universe affects the dynamic of the electroweak phase transition enhancing its strength. This effect may enlarge the window for electroweak baryogenesis in the minimal supersymmetric extension of the standard model or even resurrect the electroweak baryogenesis scenario in the standard model. We comput

T. van Ritbergen

The order alpha_s^2 contribution to the inclusive semileptonic decay width of a b quark Γ(b -> X_u e \barν_e) is calculated analytically for zero mass u quarks.

Nima Arkani-Hamed, Savas Dimopoulos, Nemanja Kaloper, John March-Russell

It was recently pointed out that the fundamental Planck mass could be close to the TeV scale with the observed weakness of gravity at long distances being due the existence of new sub-millimeter spatial dimensions. In this picture the standard model fields are localized to a $(3+1)$-dimensional wall or ``3-brane&#39;&#39;. We show that in such theories there

T. DeGrand

A comparison is made of the (quenched) light hadron spectrum and of simple matrix elements for a hypercubic fermion action (based on a fixed point action) and the clover action, both using fat links, at a lattice spacing a= 0.18 fm. Renormalization constants for the naive and improved vector current and the naive axial current are computed using Ward identit

Paolo Cea, Leonardo Cosmai

The vacuum dynamics of SU(2) lattice gauge theory is studied by means of a gauge-invariant effective action defined using the lattice Schrödinger functional. Numerical simulations are performed both at zero and finite temperature. The vacuum is probed using an external constant Abelian chromomagnetic field. The results suggest that at zero temperature the ex

O. Borisenko, M. Faber, G. Zinovjev

The phase structure of hot gauge theories with dynamical matter fields is reexamined in the canonical ensemble with respect to triality. Since this ensemble implies a projection to the zero triality sector of the theory we introduce a proper quantity which is able to reveal a critical behaviour of the theory with fundamental quarks. We discuss the properties

W. Bonivento

A large number of measurements with polarized beams and/or spin analysis of final state particles has been performed at the e^+e^- colliders LEP and SLC, providing important information on the dynamics of high energy interactions. In this paper three subjects, for which the role of spin studies was particularly relevant, will be covered: the measurements of

Richard Gass, Manash Mukherjee

We present a mathematical framework for generating thick domain wall solutions to the coupled Einstein-scalar field equations which are (locally) plane symmetric. This approach leads naturally to two broad classes of wall-like solutions. The two classes include all previously known thick domain walls. Although one of these classes is static and the other dyn

Shahar Hod

We derive a universal upper bound to the entropy of a charged system. The entropy bound follows from application of the generalized second law of thermodynamics to a gedanken experiment in which an entropy-bearing charged system falls into a charged black hole. This bound is stronger than the Bekenstein entropy bound for neutral systems.

K. Anguige, K. P. Tod

We consider the conformal Einstein equations for massless collisionless gas cosmologies which admit an isotropic singularity. After developing the general theory, we restrict to spatially-homogeneous cosmologies. We show that the Cauchy problem for these equations is well-posed with data consisting of the limiting particle distribution function at the singul

K. Anguige, K. P. Tod

We consider the conformal Einstein equations for polytropic perfect fluid cosmologies which admit an isotropic singularity. For the polytropic index gamma strictly greater than 1 and less than or equal to 2 it is shown that the Cauchy problem for these equations is well-posed, that is to say that solutions exist, are unique and depend smoothly on the data, w

L. Hao, J. Wei, S. Liu

By analyzing the Einstein&#39;s equations for the static sphere, we find that there exists a non-singular static configuration whose radius can approach its corresponding horizon size arbitrarily.

Steven Bird, Mark Liberman

`Linguistic annotation&#39; covers any descriptive or analytic notations applied to raw language data. The basic data may be in the form of time functions -- audio, video and/or physiological recordings -- or it may be textual. The added notations may include transcriptions of all sorts (from phonetic features to discourse structures), part-of-speech and sen

A. D. Rutenberg, C. Yeung

Deterministic coarse-grained descriptions of driven diffusive systems (DDS) have been hampered by apparent inconsistencies with kinetic Ising models of DDS. In the evolution towards the driven steady-state, ``triangular&#39;&#39; anisotropies in the two systems point in opposite directions with respect to the drive field. We show that this is non-universal b

P. Azaria, A. O. Gogolin, P. Lecheminant, A. A. Nersesyan

The one-dimensional spin-orbital model is studied by means of Abelian bosonization. We derive the low-energy effective theory which enables us to study small deviations from the SU(4) symmetric point. We show that there exists a massless region with algebraically decaying correlation functions, $\sim \cos(π/{2a_0} x) x^{-3/2}$. When entering the massive phas

H. Nélisse, C. Bourbonnais, H. Touchette, Y. M. Vilk

The temperature-dependent uniform magnetic susceptibility of interacting electrons in one dimension is calculated using several methods. At low temperature, the renormalization group reaveals that the Luttinger liquid spin susceptibility $χ(T) $ approaches zero temperature with an infinite slope in striking contrast with the Fermi liquid result and with the

Sathya Guruswamy, Kareljan Schoutens

We introduce the notion of `order-$k$ non-abelian exclusion statistics&#39;. We derive the associated thermodynamic equations by employing the Thermodynamic Bethe Ansatz for specific non-diagonal scattering matrices. We make contact with results obtained by different methods and we point out connections with `fermionic sum formulas&#39; for characters in a C

Igor V. Yurkevich, Igor V. Lerner

We present first results for the transmittance, T, through a 1D disordered system with an imaginary vector potential, ih, which provide a new analytical criterion for a delocalization transition in the model. It turns out that the position of the critical curve on the complex energy plane (i.e. the curve where an exponential decay of <T> is changed by a powe

Jayajit Das, Madan Rao

We show that a torque induced by the local molecular field drives the zero-temperature ordering dynamics of a conserved Heisenberg magnet to a new fixed point, characterised by exponents z=2 and $λ\approx 5.15$. Numerical solutions of the Langevin equation indicate that theories using a Gaussian closure are inconsistent even when the torque is absent. The to

A. Hucht, K. D. Usadel

The dependence of the spin reorientation transition in ultra-thin ferromagnetic films on external magnetic fields is studied. For different orientations of the applied field with respect to the film, phase diagrams are calculated within a mean field theory for the classical Heisenberg model. In particular we find that the spin reorientation transition presen

Gennadi Uimin, Wolfram Brenig

We clarify the role of crystalline electric field (CEF) induced magnetic anisotropy in the ground state and spin-wave spectrum of cubic rare-earth materials with dominating isotropic magnetic exchange interactions. In particular we study the hexaboride NdB_6 which is shown to exhibit strong spin-quadrupolar coupling. The CEF scheme is analyzed and a non-coll

Sher Alam

Following our recent conjecture to model the phenomenona of antiferromagnetism and superconductivity by quantum symmetry groups, we propose in the present note three toy models, namely, one based on $SO_{q}(3)$ the other two constructed with the $SO_{q}(4)$ and $SO_{q}(5)$ quantum groups. Possible motivations and rationale for these choices are outlined. One

F. G. Mertens, A. R. Bishop

Theories, simulations and experiments on vortex dynamics in quasi-two-dimensional magnetic materials are reviewed. These materials can be modelled by the classical two-dimensional anisotropic Heisenberg model with XY (easy-plane) symmetry. There are two types of vortices, characterized by their polarization (a second topological charge in addition to the vor

H. Y. Lee, H. -W. Lee, D. Kim

We study the phase diagram of the continuum traffic flow model of a highway with an on-ramp. Using an open boundary condition, traffic states and metastabilities are investigated numerically for several representative values of the upstream boundary flux $f_{up}$ and for the whole range of the on-ramp flux $f_{rmp}$. An inhomogeneous but time-independent tra

Xiaoqun Wang, Shaojing Qin, Lu Yu

Using the density matrix renormalization group (DMRG) technique, we carry out a large scale numerical calculation for the S=2 antiferromagnetic Heisenberg chain. Performing systematic scaling analysis for both the chain length $L$ and the number of optimal states kept in the iterations $m$, the Haldane gap $Δ(2)$ is estimated accurately as $(0.0876\pm0.0013)

Philippe Jund, Remi Jullien

We use extensive classical molecular dynamics simulations to calculate the thermal conductivity of a model silica glass. Apart from the potential parameters, this is done with no other adjustable quantity and the standard equations of heat transport are used directly in the simulation box. The calculations have been done between 10 and 1000 Kelvin and the re

Adolfo G. Eguiluz, Wei Ku

The first part of this article centers on the fact that key features of the dynamical response of weakly-correlated materials (the alkalis, Al), have been found experimentally to differ qualitatively from simple-model behavior. In the absence of ab initio theory, the surprises embodied in the experimental data were imputed to effects of dynamical correlation

Yoichi Ando, K. Nakamura

The linear ac response of the vortex system is measured locally in Bi-2212 single crystals at various doping, using a miniature two-coil mutual-inductance technique. It was found that a step-like change in the local ac response takes place exactly at the first-order transition (FOT) temperature T_{FOT}(H) determined by a global dc magnetization measurement.

Oleg Sushkov

To investigate the non-Fermi liquid behavior we consider the extended two-dimensional t-J model which includes additional hopping t&#39;&#39;. In the regime t,J << t&#39;&#39; we were able to solve the model analytically. It has a very rich phase diagram including antiferromagnetic (AF) insulator and AF strange metal with different kinds of pseudospin-single

Naoko Nakagawa, Kunihiko Kaneko

To understand the mechanism allowing for long-term storage of excess energy in proteins, we study a Hamiltonian system consisting of several coupled pendula in partial contact with a heat bath. It is found that energy absorption and storage are possible when the motion of each pendulum switches between oscillatory (vibrational) and rotational modes. The rele

E. Arcos, G. Baez, P. A. Cuatlayol, M. L. H. Prian

We present an experimental setup based on the normal modes of vibrating soap films which shows quantum features of integrable and chaotic billiards. In particular, we obtain the so-called scars -narrow linear regions with high probability along classical periodic orbits- for the classically chaotic billiards. We show that these scars are also visible at low

Ken Umeno

It is shown that superefficient Monte Carlo computations can be carried out by using chaotic dynamical systems as non-uniform random-number generators. Here superefficiency means that the expectation value of the square of the error decreases to 0 as 1/N^{2} with N successive observations for N-> infinity, whereas the conventional Monte Carlo simulation give

A. Vikhlinin, B. R. McNamara, A. Hornstrup, H. Quintana

We detect four isolated, X-ray over-luminous (Lx>2e43 [h/0.5]**-2 erg/s) elliptical galaxies (OLEGs) in our 160 square degree ROSAT PSPC survey. The extent of their X-ray emission, total X-ray luminosity, total mass, and mass of the hot gas in these systems correspond to poor clusters, and the optical luminosity of the central galaxies (M_R<-22.5 + 5 lg h) i

Joao Magueijo, Pedro G. Ferreira, Krzysztof M. Gorski

We review our recent claim that there is evidence of non-Gaussianity in the 4 Year COBE DMR data. We present some new results concerning the effect of the galactic cut upon the non-Gaussian signal. These findings imply a localization of the non-Gaussian signal on the Northern galactic hemisphere.

Joao Magueijo, Carlo Contaldi, Mark Hindmarsh

Recent developments in inflation model building, based on supersymmetry, have produced compelling models in which strings are produced at the end of inflation. In such models the cosmological perturbations are seeded both by the defects and by the quantum fluctuations. We show that such models produce qualitatively new and desirable predictions for CMB aniso

Ioannis Contopoulos, Demosthenes Kazanas, Christian Fendt

We present, for the first time, the structure of the axisymmetric force-free magnetosphere of an aligned rotating magnetic dipole, in the case in which there exists a sufficiently large charge density (whose origin we do not question) to satisfy the ideal MHD condition, ${\bf E\cdot B}=0$, everywhere. The unique distribution of electric current along the ope

M. Kramer, K. M. Xilouris, F. Camilo, D. J. Nice

We present evidence that the integrated profiles of some millisecond pulsars exhibit severe changes that are inconsistent with the moding phenomenon as known from slowly rotating pulsars. We study these profile instabilities in particular for PSR J1022+1001 and show that they occur smoothly, exhibiting longer time constants than those associated with moding.