August 2003 arXiv papers — page 9

R. S. Markiewicz

A generalized antiferromagnetic approach to the Mott transition is analyzed with special emphasis on electron doped cuprates, where evidence for electronic phase separation is weak or absent. Fluctuations are incorporated via a self-consistent renormalization, thereby deriving a `nearly-antiferromagnetic Fermi liquid' susceptibility. The calculation is s

Gen Tatara, Hiroshi Kohno

A self-contained theory of the domain wall dynamics in ferromagnets under finite electric current is presented. The current is shown to have two effects; one is momentum transfer, which is proportional to the charge current and wall resistivity ($\rhow$), and the other is spin transfer, proportional to spin current. For thick walls, as in metallic wires, the

Wen-Hui Xie, Ya-Qiong Xu, Bang-Gui Liu, D G Pettifor

An accurate density-functional method is used to study systematically half-metallic ferromagnetism and stability of zincblende phases of 3d-transition-metal chalcogenides. The zincblende CrTe, CrSe, and VTe phases are found to be excellent half-metallic ferromagnets with large half-metallic gaps (up to 0.88 eV). They are mechanically stable and approximately

Takashi Kiyama, Masayuki Itoh

Ti NMR spectra of LaTiO3 are reexamined and the orbital state of this compound is discussed. The NMR spectra of LaTiO3 taken at 1.5 K under zero external field indicate a large nuclear quadrupole splitting. This splitting is ascribed to the presence of the rather large quadrupole moment of 3d electrons at Ti sites, suggesting that the orbital liquid model pr

V. M. Loktev, Yu. G. Pogorelov

A comparative analysis has been done of the formerly established two self-consistent solutions for the density of quasiparticle states in doped d-wave superconductors, having strikingly different and disputed behavior near the Fermi energy. One of them (1) remains finite in this limit, while the other (2) tends to zero. To resolve this discrepancy, the known

C. Leigh, A. Collier Cameron, T. Guillot

High-resolution spectroscopic searches for the starlight reflected from close-in extra-solar giant planets have the capability of determining the optical albedo spectra and scattering properties of these objects. When combined with radial velocity measurements they also yield the true mass of the planet. To date, only two such planets have been targeted for

C. Leigh, A. Collier Cameron, K. Horne, A. Penny

Using improved doppler tomographic signal-analysis techniques we have carried out a deep search for starlight reflected from the giant planet orbiting the star Tau Bootis. We combined echelle spectra secured at the 4.2 m William Herschel telescope in 1998 and 1999 (which yielded a tentative detection of a reflected starlight component from the orbiting compa

E. A. Shaner, S. A. Lyon

Time-resolved transport of ballistic electrons in a two-dimensional electron gas has been measured with a resolution of less than 5ps. This was accomplished by using picosecond electrical pulses to launch electrons from the emitter of a transverse magnetic focusing structure and optoelectronically sampling the collector voltage. Both plasma resonances and th

Yu-ju Lin, Igor Teper, Cheng Chin, Vladan Vuletic

We investigate the stability of magnetically trapped atomic Bose-Einstein condensates and thermal clouds near the transition temperature at small distances 0.5 microns < d < 10 microns from a microfabricated silicon chip. For a 2 microns thick copper film the trap lifetime is limited by Johnson-noise induced currents and falls below 1 s at a distance of 4 mi

Shiho Kobayashi, Peter Meszaros, Bing Zhang

We discuss the effects of synchrotron self-absorption in the prompt emission from the reverse shock of GRB afterglows occurring in a dense environment, such as the wind of a massive stellar progenitor or a dense ISM in early galaxies. We point out that, when synchrotron losses dominate over inverse Compton losses, the higher self-absorption frequency in a de

Asantha Cooray, James J. Bock, Brian Keating, Andrew E. Lange

(Abridged) Recent cosmic microwave background anisotropy results from the Wilkinson Microwave Anisotropy Probe suggest that the universe was reionized at a redshift around 20. Such an early reionization could arise through the ionizing radiation emitted by metal-free population III stars at redshifts of 10 and higher. We discuss infrared background (IRB) sur

Johan Noldus

In this second paper, I construct a limit space of a Cauchy sequence of globally hyperbolic spacetimes. In the second section, I work gradually towards a construction of the limit space. I prove the limit space is unique up to isometry. I als show that, in general, the limit space has quite complicated causal behaviour. This work prepares the final paper in

Johan Noldus

This paper is the first of three in which I study the moduli space of isometry classes of (compact) globally hyperbolic spacetimes (with boundary). I introduce a notion of Gromov-Hausdorff distance which makes this moduli space into a metric space. Further properties of this metric space are studied in the next papers. The importance of the work can be situa

M. Coleman Miller, E. J. M Colbert

The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (roughly 3-20 solar masses), which are p

S. Gardner, J. Tandean

Direct CP violation can exist in untagged B-meson decays to self-conjugate, three-particle final states; it would be realized as a population asymmetry in the untagged decay rate across the mirror line of the Dalitz plot of the three-body decay. We explore the numerical size of this direct CP-violating effect in a variety of B-meson decays to three pseudosca

L. Ya. Glozman

The recently discovered pentaquark $Θ^+$ is described within the chiral constituent quark model. Within this picture the flavor-spin interaction between valence quarks inverts the $(1s)^4$ and $(1s)^3(1p)$ levels of the four-quark subsystem and consequently the lowest-lying pentaquark is a positive parity, I=0, J=1/2 state of the flavor antidecuplet, similar

I. Jack, D. R. T. Jones, A. F. Kord

We consider three-loop $β$-function corrections to the sparticle spectrum in the MSSM, with particular emphasis on Snowmass Benchmark points. The three loop running has little effect on the weakly interacting particle spectrum, but for the squark masses the effect can be comparable to, or greater than, that of two loop running. We extend the analysis to the

A. Mishra, K. Balazs, D. Zschiesche, S. Schramm

The effect of vacuum fluctuations on the in-medium hadronic properties is investigated using a chiral SU(3) model in the nonlinear realization. The effect of the baryon Dirac sea is seen to modify hadronic properties and in contrast to a calculation in mean field approximation it is seen to give rise to a significant drop of the vector meson masses in hot an

Elbert E. M. Chia, M. B. Salamon, H. Sugawara, H. Sato

We report measurements of the magnetic penetration depth $λ$ in single crystals of PrOs$_{4}$Sb$_{12}$ down to $\sim$0.1 K using a tunnel-diode based, self-inductive technique at 21 MHz, with the ac field applied along the \textit{a}, \textit{b} and \textit{c} directions. In all three field orientations the penetration depth and superfluid density $ρ_{s}$ te

J. Ellis, N. E. Mavromatos, A. S. Sakharov

It has been argued by Jacobson, Liberati and Mattingly that synchrotron radiation from the Crab Nebula imposes a stringent constraint on any modification of the dispersion relations of the electron that might be induced by quantum gravity. We supplement their analysis by deriving the spectrum of synchrotron radiation from the coupling of an electrically-char

M. Khanbekyan, L. Knöll, A. A. Semenov, W. Vogel

The problem of extraction of a single-mode quantum state from a high-Q cavity is studied for the case in which the time of preparation of the quantum state of the cavity mode is short compared with its decay time. The temporal evolution of the quantum state of the field escaping from the cavity is calculated in terms of phase-space functions. A general condi

Yves Brihaye, Betti Hartmann, Wojtek J. Zakrzewski

We study soliton solutions of a modified non-linear Schroedinger (MNLS) equation. Using an Ansatz for the time and azimuthal angle dependence previously considered in the studies of the spinning Q-balls, we construct multi-node solutions of MNLS as well as spinning generalisations.

James McKee, Chris Smyth

We show that there are Salem numbers of every trace. The nontrivial part of this result is for Salem numbers of negative trace. The proof has two main ingredients. The first is a novel construction, using pairs of polynomials whose zeros interlace on the unit circle, of polynomials of specified negative trace having one factor a Salem polynomial, with any ot

S. N. Dorogovtsev

We obtain the clustering coefficient, the degree-dependent local clustering, and the mean clustering of networks with arbitrary correlations between the degrees of the nearest-neighbor vertices. The resulting formulas allow one to determine the nature of the clustering of a network.

J. H. Samson

The Wigner function W(q,p) is formulated as a phase-space path integral, whereby its sign oscillations can be seen to follow from interference between the geometrical phases of the paths. The approach has similarities to the path-centroid method in the configuration-space path integral. Paths can be classified by the mid-point of their ends; short paths wher

V. I. Kukulin, V. N. Pomerantsev, Amand Faessler

Coulomb and charge-symmetry breaking effects in the $^3$He ground state within the dressed dibaryon model developed recently for $2N$ and $3N$ forces are examined in detail. Particular attention has been paid to the Coulomb displacement energy $ΔE_C=E_B(^3{\rm H})- E_B(^3{\rm He})$ and rms charge radii of $^3$H and $^3$He. A new scalar $3N$ force between the

Piotr Sitko

The exclusion statistics of quasiparticles is found at any level of the hierarchy of condensed states of composite fermion excitations (for which experimental indications have recently been found). The hierarchy of condensed states of excitations in boson Jain states is introduced and the statistics of quasiparticles is found. The quantum Hall states of char

V. I. Kukulin, V. N. Pomerantsev, M. Kaskulov, Amand Faessler

A multi-component formalism is developed to describe three-body systems with nonstatic pairwise interactions and non-nucleonic degrees of freedom. The dressed-bag model for $NN$ interaction based on the formation of an intermediate six-quark bag dressed by a $σ$-field is applied to the $3N$ system, where it results in a new three-body force between the six-q

Zhou Ya-Jin, Ma Wen-Gan, Hou Hong-Sheng, Zhang Ren-You

We investigate in detail the $γγ$ fusion production mechanisms of two neutral Higgs bosons ($h^0A^0$, $ H^0A^0$, $h^0H^0$ and $H^0H^0$) within the framework of the mSUGRA-inspired minimal supersymmetric standard model(MSSM) at an $e^+e^-$ linear colliders, which provide a probe of the trilinear Higgs self-couplings. We calculate the dependence of the product

Zhi-zhong Xing

The recent observation of B^0_d->π^0π^0 and \bar{B}^0_d->π^0π^0 decay modes allows us to make a fresh isospin analysis of B->ππtransitions. We find that current experimental data can impose some model-independent constraints on the parameter space of direct CP violation in B_d->π^+π^- and B_d->π^0π^0. Furthermore, we establish a direct relationship between t

A. Kiraz, M. Atature, A. Imamoglu

An optical source that produces single photon pulses on demand has potential applications in linear optics quantum computation, provided that stringent requirements on indistinguishability and collection efficiency of the generated photons are met. We show that these are conflicting requirements for anharmonic emitters that are incoherently pumped via reserv

Chan Yong Park

In this paper, we consider the D-brane, especially ${\rm D}_-$-brane, in the pp-wave background, which has the eight dynamical and the eight kinematical supercharges. Since the pp-wave background has not a SO(8) but a ${\rm SO}(4) \times {\rm SO}(4)$ symmetric group, the D-brane world-volume theory has a non-trivial symmetric group which depends on the confi

D. Dalmazi

We consider an arbitrary U(1) charged matter non-minimally coupled to the self-dual field in $d=2+1$. The coupling includes a linear and a rather general quadratic term in the self-dual field. By using both a Lagragian gauge embedding and a master action approaches we derive the dual Maxwell Chern-Simons type model and show the classical equivalence between

Daniel A. Lidar

A Comment on the paper &#34;Quantum waveguide array generator for performing Fourier transforms: Alternate route to quantum computing&#34; by R. Akis and D.K. Ferry, Appl. Phys. Lett. 79, 2823 (2001). The authors reply in Appl. Phys. Lett. 80, 2420 (2002).

Daniel A. Lidar

A Comment on the paper &#34;Conservative Quantum Computing&#34; by M. Ozawa, Phys. Rev. Lett. 89, 057902 (2002). The author replies in Phys. Rev. Lett. 91, 089802 (2003).

Sougato Bose

I present a general scheme through which the evidence of a superposition involving distinct classical-like states of a macroscopic system can be probed. The scheme relies on a qubit being coupled to a macroscopic harmonic oscillator in such a way that it can be used to both prepare and probe a macroscopic superposition. Two potentially realizable implementat

K. M. R. Audenaert, C. A. Fuchs, C. King, A. Winter

Two measures of sensitivity to eavesdropping for alphabets of quantum states were recently introduced by Fuchs and Sasaki in quant-ph/0302092. These are the accessible fidelity and quantumness. In this paper we prove an important property of both measures: They are multiplicative under tensor products. The proof in the case of accessible fidelity shows a con

Xiaoguang Wang, Haibin Li, Bambi Hu

We study the mode entanglement in the one-dimensional Frenkel-Kontorova model, and found that behaviors of quantum entanglement are distinct before and after the transition by breaking of analyticity. We show that the more extended the electron is, the more entangled the corresponding state. Finally, a quantitative relation is given between the average squar

Haibin Li, Xiaoguang Wang, Bambi Hu

We study bipartite entanglement in a general one-particle state, and find that the linear entropy, quantifying the bipartite entanglement, is directly connected to the paricitpation ratio, charaterizing the state localization. The more extended the state is, the more entangled the state. We apply the general formalism to investigate ground-state and dynamica

Andrew G. White, Alexei Gilchrist, Geoffrey J. Pryde, Jeremy L. O&#39;Brien

Accurate characterisation of two-qubit gates will be critical for any realisation of quantum computation. We discuss a range of measurements aimed at characterising a two-qubit gate, specifically the CNOT gate. These measurements are architecture-independent, and range from simple truth table measurements, to single figure measures such as the fringe visibil

Berthold-Georg Englert, Krzysztof Wódkiewicz

Gaussian states -- or, more generally, Gaussian operators -- play an important role in Quantum Optics and Quantum Information Science, both in discussions about conceptual issues and in practical applications. We describe, in a tutorial manner, a systematic operator method for first characterizing such states and then investigating their properties. The cent

Patrick Hayden, Richard Jozsa, Denes Petz, Andreas Winter

We give an explicit characterisation of the quantum states which saturate the strong subadditivity inequality for the von Neumann entropy. By combining a result of Petz characterising the equality case for the monotonicity of relative entropy with a recent theorem by Koashi and Imoto, we show that such states will have the form of a so-called short quantum M

V. M. Shabaev, I. I. Tupitsyn, V. A. Yerokhin, G. Plunien

A new approach to finite basis sets for the Dirac equation is developed. It solves the problem of spurious states and, as a result, improves the convergence properties of basis set calculations. The efficiency of the method is demonstrated for finite basis sets constructed from B splines by calculating the one-loop self-energy correction for a hydrogenlike i

V. Pascalutsa, D. R. Phillips

A new power-counting scheme for a chiral effective field theory that includes Delta degrees of freedom is briefly described and applied to the nucleon Compton scattering.

Yu. N. Uzikov, J. Haidenbauer

It is shown that the shoulder observed in the cross section of $p^3He$ backward elastic scattering at proton beam energies of 0.4 -- 0.7 GeV can be explained by the mechanism of virtual $π$-meson production with a dominant contribution from the subprocesses $pd^*\to ^3$He$ π^0$ and $p(pp)\to^3$He$ π^+$, where $d^*$ denotes the singlet deuteron and the $pp$ p

B. M. Kessler, G. L. Payne, W. N. Polyzou

We demonstrate that wavelet bases have features that make them advantageous for solving momentum-space scattering integral equations. Using the example of two nucleons interacting with the Malfliet-Tjon V interaction, we show it is possible to reduce the size of the matrix representation of the Lippmann-Scwhinger equation by 96% with a loss of accuracy of on

W. N. Polyzou

I formulate a class of relativistic quantum mechanical models that satisfy the cluster property and allow particle production. The models have a finite number of bare-particle degrees of freedom. The class of models include relativistic isobar models and the relativistic Lee model. I discuss elements of the construction that may be relevant to treat the gene

Robert A. Williams, Paul Gueye

We present a non-relativistic quark molecular model (QMM) of the strange crypto-exotic pentaquark baryon spectrum motivated by the recent data showing narrow, resonance enhancements in electromagnetic and hadronic production of kaons. Our model assumes color octet bonded quark molecular clusters forming exotic color singlet pentaquark baryons. We develop exp

Peter Jacobs, Jennifer Klay

We review recent measurements of high transverse momentum (high $p_T$) hadron production in nuclear collisions by the STAR Collaboration at RHIC. The previously observed suppression in central Au+Au collisions has been extended to much higher $p_T$. New measurements from d+Au collisions are presented which help disentangle the mechanisms responsible for the

W. J. Llope, F. Geurts, J. W. Mitchell, Z. Liu

A time-of-flight system was constructed for the STAR Experiment for the direct identification of hadrons produced in 197Au+197Au collisions at RHIC. The system consists of two separate detector subsystems, one called the pVPD (the &#34;start&#34; detector) and the other called the TOFp tray (the &#34;stop&#34; detector). Each detector is based on conventiona

Bindu A. Bambah

A way to construct and classify the three dimensional polynomially deformed algebras is given and the irreducible representations is presented. for the quadratic algebras 4 different algebras are obtained and for cubic algebras 12 different classes are constructed. Applications to quantum mechanical systems including supersymmetric quantum mechanics are disc

H. Murat Tuncali, E. D. Tymchatin, Vesko Valov

We prove that any closed map between metrizable spaces can be extended to a closed map between completely metrizable spaces with the same extensional dimension.

Megumi Harada, Nicholas J. Proudfoot

Given an n-tuple of positive real numbers, Konno defines an algebraic variety called a hyperpolygon space, a hyperkahler analogue of the Kahler variety parametrizing spacial polygons with fixed edge lengths. The ordinary polygon space can be interpreted as the moduli space of stable representations of a certain quiver with fixed dimension vector; from this p

Aristide Tsemo

Let $(M,ω)$ be a symplectic manifold endowed with a agrangian foliation ${\cal L}$, it has been shown by Weinstein [16] hat the symplectic structure of $M$ defines on each leaf of ${\cal L}$, connection which curvature and torsion forms vanish identically. uppose that $L_0$ is a compact leaf which Weinstein connection is eodesically complete, Molino and Curr

Brian Dean

Let M be a 3-manifold (possibly with boundary). We show that, for any positive integer g, there exists an open nonempty set of metrics on M for each of which there are stable compact embedded minimal surfaces of genus g with arbitrarily large area. This extends the result of Colding and Minicozzi for g=1.

N. Burq, P. Gerard, N. Tzvetkov

We study the cubic non linear Schrödinger equation (NLS) on compact surfaces. On the sphere $\mathbb{S}^2$ and more generally on Zoll surfaces, we prove that, for $s>1/4$, NLS is uniformly well-posed in $H^s$, which is sharp on the sphere. The main ingredient in our proof is a sharp bilinear estimate for Laplace spectral projectors on compact surfaces. On ét

Stéphane Druel

The purpose of this paper is to prove the following theorem. Let $X$ be a projective normal variety defined over an algebraically closed field of characteristic zero and let $Ω_{X}^{1}\to L$ be a one-dimensional foliation on $X$. If $L\cdot C<0$ for all curves $C\subset X$ then either the foliation is regular or else $X$ is a cone over a normal projective va

A. A. Korenovskyy, A. K. Lerner, A. M Stokolos

A multidimensional version of the Riesz rising sun lemma is proved by means of a generalized dyadic process.

Nero Budur, Marta Casanellas, Elisa Gorla

In this paper we compute the Hilbert functions of irreducible (or smooth) and reduced arithmetically Gorenstein schemes that are twisted anti-canonical divisors on arithmetically Cohen-Macaulay schemes. We also prove some folklore results characterizing the Hilbert functions of irreducible standard determinantal schemes, and we use them to produce a new clas

Jun-ichi Okuda, Kimio Ueno

The relationship between the Ohno relation and multiple polylogarithms are discussed. Using this relationship, the algebraic reduction of the Ohno relation is given.

D. T. Alves, C. Farina, P. A. Maia Neto

We derive the radiation pressure force on a non-relativistic moving plate in 1+1 dimensions. We assume that a massless scalar field satisfies either Dirichlet or Neumann boundary conditions (BC) at the instantaneous position of the plate. We show that when the state of the field is invariant under time translations, the results derived for Dirichlet and Neum

S. Fedoruk, V. G. Zima

Twistor formulation of massive arbitrary spin particle has been constructed. Twistor space of such particle is formed two twistors and two complex scalars which form together &#39;bosonic supertwistor&#39;. The formulation is deduced from space-time one for spinning particle by means of introducing auxiliary harmonic variables and consequent partial fixing o

D. Dudal, H. Verschelde, V. E. R. Lemes, M. S. Sarandy

Vacuum condensates of dimension two and their relevance for the dynamical mass generation for gluons in Yang-Mills theories are discussed

Kazuhiro Hikami, Anatol N. Kirillov

We reveal an intimate connection between the quantum knot invariant for torus knot T(s,t) and the character of the minimal model M(s,t), where s and t are relatively prime integers. We show that Kashaev&#39;s invariant, i.e., the N-colored Jones polynomial at the N-th root of unity, coincides with the Eichler integral of the character.

Sang-Jin Sin

The paper is withdrawn by the author. Parts of the contents are expanded into separate papers; hep-th/0308015 LOCALIZED TACHYON MASS AND A G-THEOREM ANALOGUE, hep-th/0308028 COMMENTS ON THE FATE OF UNSTABLE ORBIFOLDS, hep-th/0308029 CHIRAL RINGS AND GSO PROJECTION IN ORBIFOLDS.

Jianwei Qiu, Matthias Grosse Perdekamp

We summarize the activities in the spin physics parallel sessions of the $8^{\rm th}$ conference on intersections between particle and nuclear physics.

Davison E. Soper

I review some issues related to short distance QCD and its relation to the experimental program of the Large Hadron Collider (LHC) now under construction in Geneva.

Chris P. Korthals Altes

These lectures start with a brief overview of salient features of the critical region of hot QCD. The main emphasis is on the accurate description of static plasma observables by the well-known hierarchy of reduced actions combined with 3D simulations above T\sim 2T_c. A striking pattern emerges, put in perspective by completing the quasi-particle picture

Walter Winter

We discuss options to resolve correlations and degeneracies with combinations of future neutrino long-baseline experiments. We use a logarithmic scale of $\sin^2 2 θ_{13}$ as a representation for a systematical classification of the experiments.

J. D. Ashley, D. B. Leinweber, A. W. Thomas, R. D. Young

It is imperative that lattice QCD serve to develop our understanding of hadron structure and, where possible, to guide the interpretation of experimental data. There is now a great deal of effort directed at the calculation of the electroweak form factors of the nucleon, where for example, measurements at Jefferson Laboratory have recently revealed surprisin

B. Aubert

We present a study of the decay B- -> D*0 K*- based on a sample of 86 million Upsilon(4S) -> BBbar decays collected between 1999 and 2002 with the BaBar detector at the PEP-II asymmetric-energy B-Factory at SLAC. We measure the branching fraction B(B- -> D*0 K*-) = 8.3 +/- 1.1 (stat)} +/- 1.0 (syst) x 10e-4, and the fraction of longitudinal polarization in t

V. Chiochia

The measurement of the beauty quark production cross section in deep inelastic scattering with the ZEUS detector at HERA is presented. The cross section for beauty quarks, measured in the kinematic range $Q^2 > 2$ GeV$^2$ and $0.05 < y < 0.7$, and for events with at least one muon and one jet in the Breit frame, is somewhat above the next-to-leading order (N

Ivanhoe B. Pestov

A new concept of internal time (viewed as a scalar temporal field) is introduced which allows one to solve the energy problem in General Relativity. The law of energy conservation means that the total energy density of the full system of interacting fields (including gravitational field) does not vary with time, thus being the first integral of the system. I

G. Iovane

It is developed a very complex system (hardware/software) to detect luminosity variations connected with the discovery of new planets outside the Solar System. Traditional imaging approaches are very demanding in terms of computing time; then, the implementation of an automatic vision and decision software architecture is presented. It allows to perform an o

G. Iovane

A very complex vision system is developed to detect luminosity variations connected with the discovery of new planets in the Universe. The traditional imaging system can not manage a so large load. A private net is implemented to perform an automatic vision and decision architecture. It lets to carry out an on-line discrimination of interesting events by usi

J. M. Taylor, A. Imamoglu, M. D. Lukin

We present a unified description of cooling and manipulation of a mesoscopic bath of nuclear spins via coupling to a single quantum system of electronic spin (quantum bit). We show that a bath cooled by the quantum bit rapidly saturates. Although the resulting saturated states of the spin bath (``dark states&#39;&#39;) generally have low degrees of polarizat

J. Snyder, B. G. Ueland, J. S. Slusky, H. Karunadasa

We report a study of the low temperature bulk magnetic properties of the spin ice compound Dy2Ti2O7 with particular attention to the (T < 4 K) spin freezing transition. While this transition is superficially similar to that in a spin glass, there are important qualitative differences from spin glass behavior: the freezing temperature increases slightly with

Jan Burgy, Adriana Moreo, Elbio Dagotto

Previous theoretical investigations of colossal magnetoresistance (CMR) materials explain this effect using a ``clustered&#39;&#39; state with preformed ferromagnetic islands that rapidly align their moments with increasing external magnetic fields. While qualitatively successful, explicit calculations indicate drastically different typical resistivity value

Celine Kuttler, Ralf Blossey

We have performed a simulation study of the social network arising from dancing partner selection in Tango Argentino. Tango Argentino is a famous intellectual dance which combines individualistic behaviour with consensual social rules, generating complex patterns of network behaviour in time. We quantify these patterns by time-dependent degree distributions

John A Wilson

This paper seeks to synthesize much recent work on the HTSC materials around the latest energy resolved scanning tunnelling microscopy (STM) results from Davis and coworkers. The conductance diffuse scattering results in particular are employed as point of entry to discuss bosonic modes, both of condensed and uncondensed form. The bosonic mode picture is ess

A. W. Rushforth, B. L. Gallagher, P. C. Main, A. C. Neumann

We present magnetotransport results for a 2D electron gas (2DEG) subject to the quasi-random magnetic field produced by randomly positioned sub-micron Co dots deposited onto the surface of a GaAs/AlGaAs heterostructure. We observe strong local and non-local anisotropic magnetoresistance for external magnetic fields in the plane of the 2DEG. Monte-Carlo calcu

Renju Zacharia, Hendrik Ulbricht, Tobias Hertel

We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene and ovalene at sub-monolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV and 2.1 eV, respectively. Benzene and naphthalene follow simple first or

Gunter M. Schütz

Recent work on stochastic interacting particle systems with two particle species (or single-species systems with kinematic constraints) has demonstrated the existence of spontaneous symmetry breaking, long-range order and phase coexistence in nonequilibrium steady states, even if translational invariance is not broken by defects or open boundaries. If both p

Sangbum Kim, Chia-Ren Hu, Malcolm J. Andrews

A numerical scheme to study the mixed states in a mesoscopic type-II superconducting cylinder is described. Steady-state configurations and transient behavior of the magnetic vortices for various values of the applied magnetic field H are presented. Transitions between different multi-vortex states as H is changed is demonstrated by contour plots and jumps i

V. A. Yurovsky, A. Ben-Reuven

Loss of atoms from a $^{85}$Rb condensate on passage through a Feshbach resonance is analyzed using the generalized parametric approximation that takes into account quantum many-body effects. These effects lead to a substantial increase of the losses. A better agreement with experiments is achieved, compared to predictions of mean-field theories. The method

Eric Jeckelmann

In their Comment (see cond-mat/0301237), Sandvik, Sengupta, and Campbell present some numerical evidences to support the existence of an extended bond-order-wave (BOW) phase at couplings (U,V) weaker than a tricritical point (U_t,V_t) in the ground state phase diagram of the one-dimensional half-filled U-V Hubbard model. They claim that their results do not

Jian-Sheng Wang, Baowen Li

We study heat conduction in a one-dimensional chain of particles with longitudinal as well as transverse motions. The particles are connected by two-dimensional harmonic springs together with bending angle interactions. Using equilibrium and nonequilibrium molecular dynamics, three types of thermal conducting behaviors are found: a logarithmic divergence wit

Ilse M. van Bemmel, Joel Vernet, Robert A. E. Fosbury, Henny J. G. L. M. Lamers

From optical spectropolarimetry of Cygnus A we conclude that the scattering medium in the ionization cones in Cygnus A is moving outward at a speed of 170+-34 km/s, and that the required momentum can be supplied by the radiation pressure of an average quasar. Such a process could produce a structure resembling the observed ionization cones, which are thought

Hyron Spinrad

I review selected current observations of distant galaxies and our interpretation of the fragile (and occasionally contradictory) data. Galaxies at the ``contemporary limit&#39;&#39; of technology and redshift (z~6) are difficult to locate in the first place. Moreover, the large redshift may push some critical confirming and/or interpretative analysis toward

M. D. Roberts

The absolute calibration of an air fluorescence detector (FD) is an important element in correctly determining the energy of detected cosmic rays. The absolute calibration relates the flux of photons of a given wavelength at the detector aperture to the electronic signal recorded by the FD data acquisition system. For the Auger FDs, the primary absolute cali

A. E. Hornschemeier, D. M. Alexander, F. E. Bauer, W. N. Brandt

We have identified a sample of 10 highly reliable off-nuclear (> 2 kpc) X-ray sources at z=0.03-0.25 in late-type host galaxies within the two GOODS fields (i.e., the two Chandra Deep Fields). The combination of the superb spatial resolution and great depth of the HST ACS and Chandra ACIS coverage in the GOODS fields is critical to the identification of thes

Gregory Laughlin, Adriane Steinacker, Fred Adams

This paper examines how type I planet migration is affected by the presence of turbulent density fluctuations in the circumstellar disk. For type I migration, the planet does not clear a gap in the disk and its secular motion is driven by torques generated by the wakes it creates in the surrounding disk fluid. MHD turbulence creates additional density pertur

R. F. Minchin, M. J. Disney, P. J. Boyce, W. J. G. de Blok

We have carried out an extremely long integration-time (9000 s/beam) 21-cm blind survey of 60 square degrees in Centaurus using the Parkes multibeam system. We find that the noise continues to fall as sqrt(t) throughout, enabling us to reach an HI column-density limit of 4.2 x 10^18 cm^-2 for galaxies with a velocity width of 200 km/s in the central 32 squar

Michael Schubnell

It has now been firmly established that the Universe is expanding at an accelerated rate, driven by a presently unknown form of dark energy that appears to dominate our Universe today. A dedicated satellite mission has been designed to precisely map out the cosmological expansion history of the Universe and thereby determine the properties of the dark energy

P. N. Best, J. N. Arts, H. J. A. Rottgering, R. Rengelink

A new sample of radio sources, with the designated name CENSORS (A Combined EIS-NVSS Survey Of Radio Sources), has been defined by combining the NRAO VLA Sky Survey (NVSS) at 1.4 GHz with the ESO Imaging Survey (EIS) Patch D, a 3 by 2 degree region of sky centred at 09 51 36.0, -21 00 00 (J2000). New radio observations of 199 NVSS radio sources with NVSS flu

T. Suomijarvi

The detectors of the surface array of the Pierre Auger Observatory are water Cherenkov tanks. The signals from each tank are read out using three photomultipliers. The energy of the primary particle is inferred from signal densities and requires good linearity of the PMTs and a large dynamic range. The absolute time of arrival of the shower front at each tan

Maria Teresa Dova

Evidence of azimuthal asymmetries in the time structure and signal size has been found in non-vertical showers as a function of zenith angle. These asymmetries arise because of the different paths traveled by particles in the upper and lower sides of the plane perpendicular to the shower axis to reach detectors at the same axial distances. The shower particl

J. E. Ovaldsen, J. Teuber, R. Stabell, A. K. D. Evans

We present R- and V-band photometry of the gravitational lens system QSO 0957+561 from five nights (one in 2000 January and four in 2001 March, corresponding to the approximate time-delay for the system) of uninterrupted monitoring at the Nordic Optical Telescope. In the photometry scheme we have stressed careful magnitude calibration as well as corrections

J. E. Ovaldsen, J. Teuber, R. E. Schild, R. Stabell

We present a re-reduction of archival CCD frames of the doubly imaged quasar 0957+561 using a new photometry code. Aperture photometry with corrections for both cross contamination between the quasar images and galaxy contamination is performed on about 2650 R-band images from a five year period (1992-1997). From the brightness data a time delay of 424.9 +/-

S. A. E. G. Falle

This paper describes a numerical scheme for multi-fluid hydrodynamics in the limit of small mass densities of the charged particles. The inertia of the charged particles can then be neglected, which makes it possible to write an evolution equation for the magnetic field that can be solved using an implicit scheme. This avoids the severe restriction on the st