May 2002 arXiv papers

P. Coleman

This set of four lectures was originally given at the VI Training Course in the Physics of Correlated Electron systems and High-Tc Superconductors, at Vietri Sur Mare, Italy (Oct 2001). The lectures are at an introductory level with exercises. The course describes the physics of moment formation, the Kondo effect and the development of a coherent heavy elect

V. Bouchiat, N. Chtchelkatchev, D. Feinberg, G. B. Lesovik

We propose a device which implements a solid-state nanostructured electron entangler. It consists of a single-walled carbon nanotube connected at both end to normal state electrodes and coupled in its middle part to a superconducting nanowire. Such a device acts as an electronic beam splitter for correlated electrons originating from the superconductor. We f

Ying-Jer Kao, Andrew P. Iyengar, Jelena Stajic, K. Levin

Abrikosov-Gor'kov (AG) theory, the foundation for understanding pair-breaking effects in conventional superconductors, is inadequate when there is an excitation gap (pseudogap) present at the onset of superconductivity. In this paper we present an extension of AG theory within two important, and diametrically opposite approaches to the cuprate pseudogap.

Vittorio Giovannetti, Seth Lloyd, Lorenzo Maccone

Entanglement or entanglement generating interactions permit to achieve the maximum allowed speed in the dynamical evolution of a composite system, when the energy resources are distributed among subsystems. The cases of pre-existing entanglement and of entanglement-building interactions are separately addressed. The role of classical correlations is also dis

P. E. Kornilovitch, A. M. Bratkovsky, R. S. Williams

A simple experimentally accessible realization of current rectification by molecules (molecular films) bridging metal electrodes is described. It is based on the spatial asymmetry of the molecule and requires only one resonant conducting molecular level (pi-orbital). The rectification, which is due to asymmetric coupling of the level to the electrodes by tun

Yitzhak Frishman, Marek Karliner

Extending previous works on the spectrum of QCD_2, we now investigate the 2D analogue of meson-baryon scattering. We use semi-classical methods, perturbing around classical soliton solutions. We start with the abelian case, corresponding to one flavor,and find that in this case the effective potential is reflectionless. We obtain an explicit expression for t

S. Ando, Y. H. Song, T. -S. Park, H. W. Fearing

The cross sections for low-energy neutrino-deuteron reactions are calculated within heavy-baryon chiral perturbation theory employing cut-off regularization scheme. The transition operators are derived up to next-to-next-to-next-to-leading order in the Weinberg counting rules, while the nuclear matrix elements are evaluated using the wave functions generated

A. Smith

We describe two recent results using data collected with the CLEO detector at the CESR e+e- collider at energies near the Upsilon(4S). The first is a Dalitz plot analysis of the decay D0->K0spi+pi-. We observe a rich structure including the decay D0->K*+pi- which may be produced by D0-D0bar mixing or doubly Cabibbo-suppressed decays. We also search for D0-D0

Stefan C. Keller, Peter R. Wood

We present the results of non-linear pulsation modelling of 20 bump Cepheids in the LMC. By obtaining a optimal fit to the observed V,R MACHO lightcurves we have placed tight constraints on stellar parameters of M, L, Teff and well as quantities of distance modulus and reddening. We describe the mass-luminosity relation for core-He burning for intermediate m

W. Buchmuller, P. Di Bari, M. Plumacher

We study the implications of thermal leptogenesis for neutrino parameters. Assuming that decays of N_1, the lightest of the heavy Majorana neutrinos, initiate baryogenesis, we show that the final baryon asymmetry is determined by only four parameters: the CP asymmetry epsilon_1, the heavy neutrino mass M_1, the effective light neutrino mass \tilde{m}_1, and

A. P. Veselov

The hierarchy of commuting maps related to a set-theoretical solution of the quantum Yang-Baxter equation (Yang-Baxter map) is introduced. They can be considered as dynamical analogues of the monodromy and/or transfer-matrices. The general scheme of producing Yang-Baxter maps based on matrix factorisation is discussed in the context of the integrability prob

S. Majumdar, G. Balakrishnan, M. R. Lees, D. McK Paul

We report the results of a high pressure neutron diffraction study of the heavy fermion compound CeRhIn5 down to 1.8 K. CeRhIn5 is known to order magnetically below 3.8 K with an incommensurate structure. The application of hydrostatic pressure up to 8.6 kbar produces no change in the magnetic wave vector qm. At 10 kbar of pressure however, a sudden change i

V. A. Miransky, I. A. Shovkovy

The expressions for dynamical masses of quarks in the chiral limit in QCD in a strong magnetic field are obtained. A low energy effective action for the corresponding Nambu-Goldstone bosons is derived and the values of their decay constants as well as the velocities are calculated. The existence of a threshold value of the number of colors $N^{thr}_c$, divid

R. N. Mohapatra, A. Perez-Lorenzana

We construct a left-right symmetric model based on the gauge group $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ in five dimensions where both the gauge bosons and fermions reside in all five dimensions. The orbifold boundary conditions are used not only to break the gauge symmetry down to $SU(2)_L\times U(1)_Y\times U(1)_{Y'}$ but also to ``project''

Martin B. Einhorn, Jose Wudka

We revisit the proof provided by Vafa and Witten that there is no spontaneous parity breaking in theories with vector-like fermions. We argue that the various criticisms that have been leveled at the original proof do not invalidate it.

A. Karastergiou, M. Kramer, S. Johnston, A. G. Lyne

In this paper, we present a study of orthogonal polarization modes in the radio emission of PSR B1133+16, conducted within the frame of simultaneous, multi-frequency, single-pulse observations. Simultaneously observing at two frequencies (1.41 GHz and 4.85 GHz) provides the means to study the bandwidth of polarization features such as the polarization positi

A. Akylas, I. Georgantopoulos, X. Barcons

We study the XMM-Newton spectra of a sample of 32 soft X-ray selected QSOs. Our goal is to check, using the spectra of moderate redshift (z~1.5), faint (f (0.2-8 keV) > 5x10^-15 cgs) broad-line QSOs, previous claims for either significant intrinsic absorption or spectral hardening at high energies. We derive hardness ratios for all sources and furthermore we

D. -G. Welsch, Ho Trung Dung, L. Knöll

An effective Hamiltonian and equations of motion for treating both the resonant dipole-dipole interaction between two-level atoms and the resonant atom-field interaction are derived, which can suitably be used for studying the influence of arbitrary dispersing and absorbing material surroundings on these interactions. It is shown that the dipole-dipole inter

David L. Band

(Abbreviated) The detection rate of a GRB detector can be increased by using a count rate trigger with many accumulation times Dt and energy bands DE, but the nominal sensitivity is less important than how much fainter a burst could be at the detection threshold as Dt and DE are changed. Predictions of the detection rate depend on the assumed burst populatio

Ryo Namiki, Takuya Hirano

In this paper we investigate the security of a quantum cryptographic scheme which utilizes balanced homodyne detection and weak coherent pulse (WCP). The performance of the system is mainly characterized by the intensity of the WCP and postselected threshold. Two of the simplest intercept/resend eavesdropping attacks are analyzed. The secure key gain for a g

P. S. Corasaniti, E. J. Copeland

The consensus of opinion in cosmology is that the Universe is currently undergoing a period of accelerated expansion. With current and proposed high precision experiments it offers the hope of being able to discriminate between the two competing models that are being suggested to explain the observations, namely a cosmological constant or a time dependent `Q

Kingman Cheung, Wai-Yee Keung

The scenario of light gluinos and light sbottoms was advocated to explain the discrepancy between the measured and theoretical production of $b$ quarks at the Tevatron. This scenario will have model-independent predictions for $Z\to q\bar q \tilde{g} \tilde{g}$ at the $Z^0$-pole, and $e^+ e^- \to q\bar q \tilde{g} \tilde{g}$ at LEPII. We show that the data f

A. K. Hartmann, A. P. Young

We study large-scale, low-energy excitations in the Ising spin glass with Gaussian interactions in two-dimensions at zero temperature, using an optimization algorithm to determine exact ground states. Periodic boundary conditions are applied. Our results for the fractal dimension of the surface, d_s, and stiffness exponent, theta', for "droplet"

A. Marin

During 1999 the CERES experiment upgraded by the new TPC was taking data from semicentral Pb+Au collisions at 40 AGeV. The analysis of the di-electron spectra shows an enhancement in the low mass region of at least the same magnitude as previously observed at full SPS energy. The results are compared to model calculations with and without medium modification

Cristian Martinez, Ricardo Troncoso, Jorge Zanelli

A four-dimensional black hole solution of the Einstein equations with a positive cosmological constant, coupled to a conformal scalar field, is given. There is a curvature singularity at the origin, and scalar field diverges inside the event horizon. The electrically charged solution, which has a fixed charge-to-mass ratio is also found. The quartic self-int

O. H. Guseinov, E. Yazgan, S. Ozkan, A. Sezer

In this paper we have used the data of 1315 pulsars (Guseinov et al. 2002) for statistical analysis and showed the changes in pulsar parameters since the appearance of Taylor et al. (1996) catalog. Here we present the space distribution of pulsars, dispersion measures, distances from the galactic plane and from the Sun, electron density, luminosity distribut

Hiroyuki Abe, Tatsuo Kobayashi, Nobuhito Maru, Koichi Yoshioka

We present four-dimensional gauge theories that describe physics on five-dimensional curved (warped) backgrounds, which includes bulk fields with various spins (vectors, spinors, and scalars). Field theory on the AdS$_5$ geometry is examined as a simple example of our formulation. Various properties of bulk fields on this background, e.g., the mass spectrum

Ken D. Olum, Noah Graham

We show that a system of a domain wall coupled to a scalar field has static negative energy density at certain distances from the domain wall. This system provides a simple, explicit example of violation of the averaged weak energy condition and the quantum inequalities by interacting quantum fields. Unlike idealized systems with boundary conditions or exter

B. Feigin, M. Jimbo, R. Kedem, S. Loktev

The fusion rule gives the dimensions of spaces of conformal blocks in the WZW theory. We prove a dimension formula similar to the fusion rulefor spaces of coinvariants of affine Lie algebras g^. An equivalence of filtered spaces is established between spaces of coinvariants of two objects: highest weight g^-modules and tensor products of finite-dimensional e

S. Deser, Bayram Tekin

We define the notion of energy, and compute its values, for gravitational systems involving terms quadratic in curvature. While our construction parallels that of ordinary Einstein gravity, there are significant differences both conceptually and concretely. In particular, for D=4, all purely quadratic models admit vacua of arbitrary constant curvature. Their

J. Besprosvany

We criticize the current standard interpretation of quantum mechanics, review its paradoxes with attention to non-locality, and conclude that a reconsideration of it must be made. We underline the incompatibility of the conceptions ascribed to space of field, and stage in modern theories, with differing roles for coordinates. We hence trace the non-locality

A. Imamoglu

Single-photon detection and photon counting play a central role in a large number of quantum communication and computation protocols. While the efficiency of state-of-the-art photo-detectors is well below the desired limits, quantum state measurements in trapped ions can be carried out with efficiencies approaching 100%. Here, we propose a method that can in

Alexander Yu. Vlasov

A review by A. Peres [quant-ph/0205076] appears recently. It is difficult to add something to such kind of fundamental themes, but here is briefly presented some ideas about challenges of the no-cloning theorem and imaginary modifications of quantum mechanics, that could make precise cloning possible.

Mattias Johnsson, Evgeny Korsunsky, Michael Fleischhauer

Resonantly enhanced four wave mixing in double-Lambda systems is limited by ac-Stark induced nonlinear phase shifts. With counter-propagating pump fields the intensity-phase coupling has minimal impact on the dynamics, but it is of critical importance for co-propagation. The nonlinear phase terms lead to an increase of the conversion length linearly proporti

Lieven M. K. Vandersypen

We have taken significant steps towards the realization of a practical quantum computer: using nuclear spins and magnetic resonance techniques at room temperature, we provided proof of principle of quantum computing in a series of experiments which culminated in the implementation of the simplest instance of Shor's quantum algorithm for prime factorizati

Joerg Evers, Christoph H. Keitel

We propose a very simple scheme to slow down the usual exponential decay of upper state population in an atomic two level system considerably. The scheme makes use of an additional intense field with frequency lower than the total decay width of the atomic transition. This allows for additional decay channels with the exchange of one or more low-frequency ph

Ioan Sturzu

The paper gives the main lines of a general theory for physical measurements.

Robert Alicki

The theory of quantum dynamical semigroups within the mathematically rigorous framework of completely positive dynamical maps is reviewed. First, the axiomatic approach which deals with phenomenological constructions and general mathematical structures is discussed. Then basic derivation schemes of the constructive approach including singular coupling, weak

Michael A. Nielsen, Michael J. Bremner, Jennifer L. Dodd, Andrew M. Childs

What interactions are sufficient to simulate arbitrary quantum dynamics in a composite quantum system? Dodd et al. (quant-ph/0106064) provided a partial solution to this problem in the form of an efficient algorithm to simulate any desired two-body Hamiltonian evolution using any fixed two-body entangling N-qubit Hamiltonian, and local unitaries. We extend t

J. H. Misguich, J. D. Reuss, D. Constantinecu, Gy. Steinbrecher

Single trajectories of magnetic line motion indicate the persistence of a central protected plasma core, surrounded by a chaotic shell enclosed in a double-sided transport barrier : the latter is identified as being composed of two Cantori located on two successive "most-noble" numbers values of the perturbed safety factor, and forming an internal tr

Martin Nilsson

This paper is a study of continuous time Singular Spectrum Analysis (SSA). We show that the principal eigenfunctions are solutions to a set of linear ODEs with constant coefficients. We also introduce a natural generalization of SSA, constructed using local (Lie-) transformation groups. The time translations used in standard SSA is a special case. The eigenf

Carlos Gershenson, Mason A. Porter, Andrej Probst, Matus Marko

In this paper we compare the relevance of information obtained from "discriminative" media and from "non-discriminative" media. Discriminative media are the ones which accumulate and deliver information using a heuristic selection of it. This can be made by humans, or by artificial intelligent systems, exhibiting some form of "knowledge&#

Carlos Gershenson

We present several philosophical ideas emerging from the studies of complex systems. We make a brief introduction to the basic concepts of complex systems, for then defining "abstraction levels". These are useful for representing regularities in nature. We define absolute being (observer independent, infinite) and relative being (observer dependent,

S. Yu. Vernov

The Hénon--Heiles system in the general form is studied. In a nonintegrable case new solutions have been found as formal Laurent series, depending on three parameters. One of parameters determines a location of the singularity point, other parameters determine coefficients of the Laurent series. For some values of these two parameters the obtained Laurent se

T. Constantinescu

In this paper we introduce and discuss some classes of orthogonal polynomials in several non-commuting variables. The emphasis is on a non-commutative version of the orthogonal polynomials on the real line. We introduce recurrence equations for these polynomials, Christoffel-Darboux formulas, and Jacobi type matrices.

Franz Peherstorfer, Peter Yuditskii

Let $E$ be a homogeneous compact set, for instance a Cantor set of positive length. Further let $σ$ be a positive measure with $\text{supp}(σ)=E$. Under the condition that the absolutely continuous part of $σ$ satisfies a Szegö--type condition we give an asymptotic representation, on and off the support, for the polynomials orthonormal with respect to $σ$. F

Stefan Geschke, Martin Goldstern, Menachem Kojman

We investigate the Ramsey theory of continuous pair-colorings on complete, separable metric spaces, and apply the results to the problem of covering a plane by functions. The homogeneity number hm(c) of a pair-coloring c:[X]^2 -> 2 is the number of c-homogeneous subsets of X needed to cover X. We isolate two continuous pair-colorings on the Cantor space 2^om

Claire Voisin

We consider the generic Green conjecture on syzygies of a canonical curve, and particularly the following reformulation thereof: {\it For a smooth projective curve $C$ of genus $g$ in characteristic 0, the condition ${\rm Cliff} C>l$ is equivalent to the fact that $K_{g-l'-2,1}(C,K_C)=0, \forall l'\leq l$.} We propose a new approach, which allows up

Sergei Chmutov

Recently N.A'Campo suggested a construction of a link from a generic immersion of a curve into a 2-disk. It is tightly related to the singularity theory. In this paper, we give a simple procedure to draw a diagram of the link from a picture of the curve.

Valeriy Bulitko

This paper studies the formation of logical operations from pre-logical processes. We are concerned with the reasons for certain mental processes taking form of logical reasoning and the underlying drives for consolidation of logical operations in human mind. Starting from Piaget's approach to Logic (Piaget, 1956) we discuss whether the evolutionary adap

E. Galina, A. Kaplan, L. Saal

A description of the real, complete modules over the Clifford algebra of a Hilbert space, with the elements of the latter acting by skew-symmetric operators.

Victor V. Batyrev, Evgeny N. Materov

We develop some ideas of Morrison and Plesser and formulate a precise mathematical conjecture which has close relations to toric mirror symmetry. Our conjecture, we call it Toric Residue Mirror Conjecture, claims that the generating functions of intersection numbers of divisors on a special sequence of simplicial toric varieties are power series expansions o

Jorgen Rasmussen

We study affine osp(1|2) fusion, the fusion in osp(1|2) conformal field theory, for example. Higher-point and higher-genus fusion is discussed. The fusion multiplicities are characterized as discretized volumes of certain convex polytopes, and are written explicitly as multiple sums measuring those volumes. We extend recent methods developed to treat affine

Massimo Bianchi, Burkhard Eden, Giancarlo Rossi, Yassen S. Stanev

We resolve the mixing of the scalar operators of naive dimension 4 belonging to the representation 20' of the SU(4) R-symmetry in N=4 SYM. We compute the order g^2 corrections to their anomalous dimensions and show the absence of instantonic contributions thereof. Ratios of the resulting expressions are irrational numbers, even in the large N limit where

Ewald Roessl, Mikhail Shaposhnikov

We present regular solutions for a brane world scenario in the form of a 't Hooft-Polyakov monopole living in the three-dimensional spherical symmetric transverse space of a seven-dimensional spacetime. In contrast to the cases of a domain-wall in five dimensions and a string in six dimensions, there exist gravity-localizing solutions for both signs of t

I. Ennes, C. Lozano, S. Naculich, H. Schnitzer

Four-dimensional N=2 gauge theories may be obtained from configurations of D-branes in type IIA string theory. Unitary gauge theories with two-index representations, and orthogonal and symplectic gauge theories, are constructed from configurations containing orientifold planes. Models with two orientifold planes imply a compact dimension, and correspond to e

S. S. Bulanov

The phases of terms of amplitude that arise from the $ππ$ interaction are obtained by using a simple realistic model of $ππ$ interaction via virtual $ρ$-meson, instead of the ChPT. It is shown that the standard ChPT approach cannot reproduce the contribution of the $ρ$-meson to the $ππ$ interaction. It is shown that the interference between the terms of ampl

Jonathan L. Rosner

The Standard Model of electroweak and strong interactions is reviewed in a pedagogical set of lectures. After an introduction to the quarks, leptons, and gauge bosons, an elementary discussion of gauge theories is given, with application to quantum chromodynamics. The physics of $W$ bosons, electroweak unification, and $Z$ bosons is then described, ending wi

E. O. Iltan

We study the branching ratio, CP-violating asymmetry, forward-backward asymmetry and the CP-violating asymmetry in the forward-backward asymmetry for the exclusive decay B--> K l^+ l^-$ in the two Higgs doublet model with tree level flavor changing neutral currents (model III). We analyse the dependencies of these quantities on the neutral Higgs boson contri

H. Kröger, X. Q. Luo, K. J. M. Moriarty

The Monte Carlo (MC) Hamiltonian is a new stochastic method to solve many-body problems. The MC Hamiltonian represents an effective Hamiltonian in a finite energy window. We construct it from the classical action via Monte Carlo with importance sampling. The MC Hamiltonian yields the energy spectrum and corresponding wave functions in a low energy window. Th

H. Suganuma, H. Matsufuru, Y. Nemoto, T. T. Takahashi

With the smearing technique, the three-quark (3Q) ground-state potential $V_{\rm 3Q}$ is numerically extracted in the SU(3)$_c$ lattice QCD Monte Carlo simulation with $12^3 \times 24$ and $β=5.7$ at the quenched level. With accuracy better than a few %, $V_{\rm 3Q}$ is well described by a sum of a constant $C_{\rm 3Q}$, the two-body Coulomb part $-A_{\rm 3Q

S. -K. Choi

We report the observation of a narrow peak in the KsK-pi+ invariant mass distribution in a sample of exclusive B-->K KsK-pi+ decays collected with the Belle detector at the KEKB asymmetric energy e+e- collider. The measured mass of the peak is M=3654+-6(stat)+-8(syst) MeV/c^2 and we place a 90% confidence level upper limit on the width of Gamma<55 MeV/c^2. T

H1 Collaboration, C. Adloff

Results on diffractive photoproduction of psi(2S) mesons are presented using data collected between 1996 and 2000 with the H1 detector at the HERA ep collider. The data correspond to an integrated luminosity of 77 pb^(-1). The energy dependence of the diffractive psi(2S) cross section is found to be similar to or possibly somewhat steeper than that for J/psi

B Collaboration

Using the HERA-B detector, the b-bbar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b-bbar production was tagged via inclusive bottom quark decays into J/psi, by exploiting the longitudinal separation of J/psi->ll decay vertices from the primary proton-nucleus interaction. Both $e^+e^-$ and $μ^+μ^

The Belle Collaboration, K. Abe

We report the observation of prompt J/psi via double ccbar production from the e+e- continuum. In this process one ccbar pair fragments into a J/psi meson while the remaining pair either produces a bound charmonium state or fragments into open charm. Both cases have been observed: the first by studying the mass spectrum of the system recoiling against the J/

John E. Heighway

Standard treatments of general relativity accept the gravitational slowing of clocks as a primary phenomenon, requiring no further analysis as to cause. Rejecting this attitude, I argue that one or more of the fundamental &#34;constants&#34; governing the quantum mechanics of atoms must depend upon position in a gravitational field. A simple relationship gov

Maher M. Abdelhadi, J. A. Jung

We investigated the anomalous peak resistivity below the onset $T_c$ in underdoped YBCO, reminiscent of that observed in 1D wires of conventional superconductors. We performed measurements of the angular dependence of resistivity $ρ(θ)$ in a magnetic field and the temperature dependence of resistivity $ρ(T)$, which exhibit a peak for $\textbf{B} \parallel$ a

L. E. Muzzy, M. Avdeev, G. Lawes, M. K. Haas

The structure and physical properties of the Zr-stabilized, nonstoichiometric molybdenum diboride superconductor are reported. Good quality material of the diboride structure type can only be obtained by partial substitution of Zr for Mo, and the quenching of melts. The phase is best made with boron in excess of the ideal 2:1 boron to metal ratio. Powder neu

S. Zvyagin, B. C. Watson, Ju-Hyun Park, D. A. Jensen

ESR studies at 9.27, 95.4, and 289.7 GHz have been performed on (C$_5$H$_{12}$N)$_2$CuBr$_4$ down to 3.7 K. The 9.27 GHz data were acquired with a single crystal and do not indicate the presence of any structural transitions. The high frequency data were collected with a polycrystalline sample and resolved two absorbances, consistent with two crystallographi

Sumiyoshi Abe, Tsunehiro Kobayashi

Microcanonical ensemble theory of bosons is derived from quantum mechanics by making use of a hidden gauge structure. The relative phase interaction associated with this gauge structure, described by the Pegg-Barnett formalism, is shown to lead to perfect decoherence in the thermodynamics limit and the principle of equal a priori probability, simultaneously.

Sameet Sreenivasan, Don R. Baker, Gerald Paul, H. Eugene Stanley

We perform Monte Carlo simulations to determine the average excluded area $<A_{ex}>$ of randomly oriented squares, randomly oriented widthless sticks and aligned squares in two dimensions. We find significant differences between our results for randomly oriented squares and previous analytical results for the same. The sources of these differences are explai

A. Gurevich

A theory of nonlinear dynamics of mixed Abrikosov vortices with Josephson cores (AJ vortices) on low-angle grain boundaries (GB) in superconductors is proposed. Dynamics and pinning of AJ vortices determine the in-field current transport through GB and the microwave response of polycrystal in the crucial misorientation range $\vartheta < 20-30^{\circ}$ of th

E. Kierlik, P. A. Monson, M. L. Rosinberg, G. Tarjus

We present a theoretical study of capillary condensation of fluids adsorbed in mesoporous disordered media. Combining mean-field density functional theory with a coarse-grained description in terms of a lattice-gas model allows us to investigate both the out-of-equilibrium (hysteresis) and the equilibrium behavior. We show that the main features of capillary

Christian Tutschka, Jose A. Cuesta

We deduce an overcomplete free energy functional for D=1 particle systems with next neighbor interactions, where the set of redundant variables are the local block densities $\varrho_i$ of $i$ interacting particles. The idea is to analyze the decomposition of a given pure system into blocks of $i$ interacting particles by means of a mapping onto a hard rod m

R. C. Ball, E. Somfai

We present a new theoretical framework for Diffusion Limited Aggregation and associated Dielectric Breakdown Models in two dimensions. Key steps are understanding how these models interrelate when the ultra-violet cut-off strategy is changed, the analogy with turbulence and the use of logarithmic field variables. Within the simplest, Gaussian, truncation of

Barbara Drossel

The Olami--Feder--Christensen earthquake model is often considered the prototype dissipative self--organized critical model. It is shown that the size distribution of events in this model results from a complex interplay of several different phenomena, including limited floating--point precision. Parallels between the dynamics of synchronized regions and tho

B. Roessli, P. Böni, W. E. Fischer, Y. Endoh

Using polarized inelastic neutron scattering the antisymmetric part of the dynamical susceptibility in non-centrosymmetric MnSi is determined. The paramagnetic fluctuations are found to be incommensurate with the chemical lattice and to have a chiral character. We show that antisymmetric interactions must be taken into account to properly describe the critic

H. W. Diehl

An introduction to the theory of critical behavior at Lifshitz points is given, and the recent progress made in applying the field-theoretic renormalization group (RG) approach to $ϕ^4$ $n$-vector models representing universality classes of $m$-axial Lifshitz points is surveyed. The origins of the difficulties that had hindered a full two-loop RG analysis ne

Jonathan C. Tan

I review the arguments motivating models for massive star formation via stellar collisions. I then describe how the standard accretion scenario, involving the collapse of a quasi-hydrostatic gas core, can produce high-mass stars in the pressurized regions of forming star clusters. I argue that the observational evidence, particularly in the Orion hot core, f

R. J. Tuffs, C. Gabriel

The ``P32&#39;&#39; Astronomical Observation Template (AOT) provided a means to map large areas of sky (up to 45x45 arcmin) in the FIR at high redundancy and with sampling close to the Nyquist limit using the ISOPHOT C100 (3x3) and C200 (2x2) detector arrays on board ISO. However, the transient response behaviour of the Ga:Ge detectors, if uncorrected, can l

Gaspar A. Bakos, Jozsef Lazar, Istvan Papp, Pal Sari

Having been operational at Kitt Peak for more than a year, the prototype of the Hungarian Automated Telescope (HAT-1) has been used for all-sky variability search of the northern hemisphere. The small autonomous observatory is recording brightness of stars in the range of I~6--13m with a telephoto lens and its 9x9 degree field of view, yielding a data rate o

E. T. Vishniac, A. Lazarian, J. Cho

Astrophysical objects with negligible resistivity are often threaded by large scale magnetic fields. The generation of these fields is somewhat mysterious, since a magnetic field in a perfectly conducting fluid cannot change the flux threading a fluid element, or the field topology. Classical dynamo theory evades this limit by assuming that magnetic reconnec

T. M. Heckman, C. A. Norman, D. K. Strickland, K. R. Sembach

We present a unified analysis of the O{\sc vi} absorption-lines seen in the disk and halo of the Milky Way, high velocity clouds, the Magellanic Clouds, starburst galaxies, and the intergalactic medium. We show that these disparate systems define a simple relationship between the O{\sc vi} column density and absorption-line width that is independent of the O

John M. Carpenter

A 5.2&#39; x 5.2&#39; region toward the young cluster IC 348 has been imaged in the millimeter continuum at 4.0&#34; x 4.9&#34; resolution with the OVRO interferometer to a RMS noise level of 0.75 mJy/beam at 98 GHz. The data are used to constrain the circumstellar disk masses in a cluster environment at an age of about 2 Myr. The mosaic encompasses 95 known

N. Castro-Rodriguez, M. Lopez-Corredoira, M. L. Sanchez-Saavedra, E. Battaner

From a comparison of the different parameters of warped galaxies in the radio, and especially in the visible, we find that: a) No large galaxy (large mass or radius) has been found to have high amplitude in the warp, and there is no correlation of size/mass with the degree of asymmetry of the warp. b) The disc density and the ratio of dark to luminous mass s

A. A. Lutovinov, S. V. Molkov, S. A. Grebenev, M. N. Pavlinsky

Results of observations of X-ray bursters in the Galactic Center region carried out with the RXTE observatory and the ART-P telescope on board GRANAT are presented. Eight X-ray bursters (A1742-294, SLX1744-299/300, GX3+1, GX354-0, SLX1732-304, 4U1724-307, KS1731-260) were revealed in this region during five series of observations which were performed with th

Kurt W. Weiler, Nino Panagia, Marcos J. Montes

Since 1997 the afterglow of gamma-ray bursting sources (GRBs) has occasionally been detected in the radio, as well in other wavelengths bands. In particular, the interesting and unusual gamma-ray burst GRB980425, thought to be related to the radio supernova SN1998bw, is a possible link between the two classes of objects. Analyzing the extensive radio emissio

M. A. Voronkov, V. I. Slysh, F. Palagi, G. Tofani

We report VLBI observations of methanol masers in the brightest 5(1)-6(0) A+ transition at 6.7 GHz in NGC 281W, 18151-1208 and 19388+2357. Using the fringe rate method absolute positions were obtained for all observed sources. A linear ordered structure with a velocity gradient was revealed in NGC 281W. Under assumption that such structure is an edge-on Kepl

XiaoHu Yang, H. J. Mo, Guinevere Kauffmann, YaoQuan Chu

McKay et al. (2002) have recently used measurements of weak galaxy-galaxy lensing in the Sloan Digital Sky Survey to estimate the cross correlation between galaxies and the projected dark matter density field. They derive a relation between aperture mass within a radius of $260\kpch$, $M_{260}$, and lens galaxy luminosity, that does not depend on galaxy lumi

Luca Amendola, Domenico Tocchini-Valentini

In most models of dark energy the structure formation stops when the accelerated expansion begins. In contrast, we show that the coupling of dark energy to dark matter may induce the growth of perturbations even in the accelerated regime. In particular, we show that this occurs in the models proposed to solve the cosmic coincidence problem, in which the rati

Marco Limongi, Alessandro Chieffi

In this review we compare the three existing sets of theoretical yields of zero metal massive stars available in the literature. We also show how each of these three different sets of yields fits the element abundance ratios observed in the extremely metal poor star CD 38245. We find that, at present, no theoretical set of yields of zero metal massive stars

Alessandro Chieffi, Marco Limongi

We present a detailed comparison between an extended set of elemental abundances observed in some of the most metal poor stars presently known and the ejecta produced by a generation of primordial core collapse supernovae. We used five stars which form our initial database and define a &#34;template&#34; ultra metal poor star which is then compared to the th

J. Brand, L. Baldacci, D. Engels

We present an overview of the long-term water maser monitoring program of a sample of late-type stars, carried out with the Medicina 32-m and Effelsberg 100-m telescopes, and describe the results in some detail. The role the SRT (Sardinia Radio Telescope) could play in this program is outlined.

Dirk H. Rischke, Igor A. Shovkovy

In a two-flavor color superconductor, the SU(3)_c gauge symmetry is spontaneously broken by diquark condensation. The Nambu-Goldstone excitations of the diquark condensate mix with the gluons associated with the broken generators of the original gauge group. It is shown how one can decouple these modes with a particular choice of &#39;t Hooft gauge. We then

D. E. Feldman, V. M. Vinokur

We demonstrate that the arbitrarily weak quenched disorder on the surface of a system of continuous symmetry destroys long range order in the bulk, and, instead, quasi-long range order emerges. Correlation functions are calculated exactly for the two- and three-dimensional XY model with surface randomness via the functional renormalization group. Even at str

Marc Hemsendorf, David Merritt

We use a systolic N-body algorithm to evaluate the linear stability of the gravitational N-body problem for N up to 1.3 x 10^5, two orders of magnitude greater than in previous experiments. For the first time, a clear ~ln N-dependence of the perturbation growth rate is seen. The e-folding time for N = 10^5 is roughly 1/20 of a crossing time.

Alexander Friedland, Hitoshi Murayama, Maxim Perelstein

The possibility that the energy density of the Universe is dominated by a network of low-tension domain walls provides an alternative to the commonly discussed cosmological constant and scalar-field quintessence models of dark energy. We quantify the lower bound on the number density of the domain walls that follows from the observed near-isotropy of the cos

Matthias Klein

We analyze theories in which a supersymmetric sector is coupled to a supersymmetry-breaking sector described by a non-linear realization. We show how to consistently couple N=1 supersymmetric matter to non-supersymmetric matter in such a way that all interactions are invariant under non-linear supersymmetry transformations. We extend this formalism to couple

Min-xin Huang

In this paper we calculate three-string interaction from light cone string field theory in pp-wave. We find exact agreements with the free planar three point functions of non-chiral BMN operators of ${\cal N} = 4$ super Yang Mills. The three string interaction vertex involving the Neumann matrices was derived in a recent paper hep-th/0204146. We explicitly c

E. Korotyaev, I. V. Krasovsky

We obtain bounds for the spectrum and for the total width of the spectral gaps for Jacobi matrices on $\ell^2(\Z)$ of the form $(Hψ)_n= a_{n-1}ψ_{n-1}+b_nψ_n+a_nψ_{n+1}$, where $a_n=a_{n+q}$ and $b_n=b_{n+q}$ are periodic sequences of real numbers. The results are based on a study of the quasimomentum $k(z)$ corresponding to $H$. We consider $k(z)$ as a conf