December 2003 arXiv papers — page 7

K. E. Khor, Sankar Das Sarma

Recent experiments show that the islanding behavior during chemical vapor deposition (CVD) of Si on Si(111) using disilane (Si${_2}$H${_6}$) is quite different from that due to molecular beam epitaxy (MBE). While the latter can be understood using rate equation theories (RET), the islanding exponent (connecting the power law growth of island density with gro

Ying Zhang, S. Das Sarma

We calculate numerically the quasiparticle effective mass (m*) renormalization as a function of temperature and electron density in two- and three-dimensional electron systems with long-range Coulomb interaction. In two dimensions, the leading temperature correction is linear and positive with the slope being a universal density independent number in the hig

D. -S. Lee, K. -I. Goh, B. Kahng, D. Kim

We study the evolution of random graphs where edges are added one by one between pairs of weighted vertices so that resulting graphs are scale-free with the degree exponent $γ$. We use the branching process approach to obtain scaling forms for the cluster size distribution and the largest cluster size as functions of the number of edges $L$ and vertices $N$.

Daniel C. Vernon

A simple example of a non-equilibrium system for which fluctuations are important is a system of particles which diffuse and may annihilate in pairs on contact. The renormalization group can be used to calculate the time dependence of the density of particles, and provides both an exact value for the exponent governing the decay of particles and an epsilon-e

P. F. Gora

The system discussed recently in L. Cao and D. J. Wu, Europhys. Lett. {\bf 61}, (2003) 593 merely reproduces properties of the input signal.

Mark R. Krumholz, Christopher F. McKee, Richard I. Klein

We introduce a new computational method for embedding Lagrangian sink particles into an Eulerian calculation. Simulations of gravitational collapse or accretion generally produce regions whose density greatly exceeds the mean density in the simulation. These dense regions require extremely small time steps to maintain numerical stability. Smoothed particle h

Ian J. O'Dwyer, Marco Bersanelli, Jeffrey Childers, Newton Figueiredo

The Background Emission Anisotropy Scanning Telescope (BEAST) is a 2.2m off-axis telescope with an 8 element mixed Q (38-45GHz) and Ka (26-36GHz) band focal plane, designed for balloon borne and ground based studies of the Cosmic Microwave Background. Here we present the Cosmic Microwave Background (CMB) angular power spectrum calculated from 682 hours of da

N. A. Webb, J. -F. Olive, D. Barret

We present XMM-Newton MOS imaging and PN timing data of the millisecond pulsar PSR J0218+4232. We confirm the previously detected pulsations of PSR J0218+4232 and we show that the folded lightcurve is dependent on energy. We present the broad band (0.2-10.0 keV) spectrum of this millisecond pulsar, as well as the spectra of: the pulsed emission, the individu

Houri Ziaeepour

The mystery of the Dark energy is not just its smallness. The extreme fine tuning of its density in the Early Universe such that it permits galaxy formation before creating a new inflationary epoch is its other unexplained aspect. Here we propose a model based on the very slow decay of a Super Heavy Dark Matter (SDM), presumed candidate for the origin of the

Brian Thomas, Edward Shaya

We propose the beginnings of a data model for the Virtual Observatory (VO) built up from simple ``quantity'' objects. In this paper we present how an object-oriented, domain (or namespace)-scoped simple quantity may be used to describe astronomical data. Our model is designed around the requirements that it be searchable and serve as a transport mech

P. T. O'Brien, J. N. Reeves, D. Watson, J. Osborne

Analysis of observations with XMM-Newton have made a significant contribution to the study of Gamma-ray Burst (GRB) X-ray afterglows. The effective area, bandpass and resolution of the EPIC instrument permit the study of a wide variety of spectral features. In particular, strong, time-dependent, soft X-ray emission lines have been discovered in some bursts.

M. Choudhury, A. R. Rao

Cygnus X-3, among the Galactic X-ray binaries, is one of the brightest radio sources. Radio image as well as spectral analysis shows the presence of outflow in the form of jets. The SED in the X-ray band shows a complicated structure and evolution. Here we review some recent results of the correlation of the long-term radio and X-ray emission, in the various

J. E. Truemper, V. Burwitz, F. Haberl, V. E. Zavlin

We discuss recent Chandra and XMM-Newton observations of the bright isolated neutron star RX J1856.5-3754 and suggest that the absence of any line features is due to effects of a high magnetic field strength (~10^13 G). Using different models for the temperature distribution across the neutron star surface assuming blackbody emission to fit the optical and X

A. J. Blustin, M. J. Page, G. Branduardi-Raymont

We present XMM-Newton observations of four BL Lac objects (1H1219+301, H1426+428, Markarian 501 and PKS 0548-322), which have been found with past X-ray missions to contain evidence of broad soft X-ray absorption features. Observations with the high resolution Reflection Grating Spectrometers on XMM-Newton provide the best chance yet of investigating these f

J. Patris, M. Dennefeld, G. Lagache, H. Dole

We present optical spectroscopy of the brightest 170 microns sources in the FIRBACK South Marano (FSM) field. The survey is 90% complete at the 4 sigma level. The spectra are compared with those of a reference sample of faint IRAS (60 microns selected) sources observed in the same conditions . The galaxies in both samples are characterized by a predominance

Harold W. Yorke

The collapse of massive molecular clumps can produce high mass stars, but the evolution is not simply a scaled-up version of low mass star formation. Outflows and radiative effects strongly hinder the formation of massive stars via accretion. A necessary condition for accretion growth of a hydrostatic object up to high masses M > 20 M_sun (rather than coales

E. V. Polyachenko

This paper presents a new approach to studying galactic structures. They are considered as the low-frequency normal modes in a disc of orbits precessing at different angular speeds. Such a concept is an adequate alternative to the commonly used approach of treating the disc as a set of individual stars rotating at near-circular orbits around the centre. The

A. de Candia, E. Del Gado, A. Fierro, N. Sator

By means of molecular dynamics, we study a model system for colloidal suspensions where the interaction is based on a competition between attraction and repulsion. At low temperatures the relaxation time $τ$ first increases as a power law as a function of the volume fraction $ϕ$ and then, due to the finite lifetime of the bonded structures, it deviates from

F. Olness, J. Pumplin, D. Stump, J. Huston

We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and anti-strange parton distributions, $s(x)$ and $\bar{s}(x)$. To explore the strangeness sector, we adopt a general parametrization of the non-perturbative $s(x), \bar{s}(x)$ functions satisfying basic QCD requirements.

R. S. Markiewicz

A simple antiferromagnetic approach to the Mott transition was recently shown to provide a satisfactory explanation for the Mott gap collapse with doping observed in photoemission experiments on electron-doped cuprates. Here this approach is extended in a number of ways. RPA, mode coupling (via self-consistent renormalization), and (to a limited extent) self

Bin Wu, Bo-Qiang Ma

We estimate the mass and the width of pentaquark $Θ^*$ states in the 27-plet from chiral soliton models. The calculations show that the mass of $Θ^*$ is about 1.60 GeV and the width for the process $Θ^*\to {KN}$ is less than 43 MeV. We also discuss the search for the existence of $Θ^*$ states in physical processes.

Carl E. Carlson, Christopher D. Carone, Herry J. Kwee, Vahagn Nazaryan

We present a consistent color-flavor-spin-orbital wave function for a positive parity Theta^+ that naturally explains the observed narrowness of the state. The wave function is totally symmetric in its flavor-spin part and totally antisymmetric in its color-orbital part. If flavor-spin interactions dominate, this wave function renders the positive parity The

Roshan Foadi, Shrihari Gopalakrishna, Carl Schmidt

We investigate unitarity of $W^+W^-$ scattering in the context of theory space models of the form $U(1)\times {[SU(2)]}^N\times SU(2)_{N+1}$, which are broken down to $U(1)_{EM}$ by non-linear $Σ$ fields, without the presence of a physical Higgs Boson. By allowing the couplings of the U(1) and the final $SU(2)_{N+1}$ to vary, we can fit the $W$ and $Z$ masse

Y. M. Lipkin, E. O. Ofek, A. Gal-Yam, E. M. Leibowitz

(Abridged) We present densely sampled BVRI light curves of the optical transient associated with the gamma-ray burst GRB 030329, the result of a coordinated observing campaign conducted at five observatories. Augmented with published observations of this GRB, the compiled optical dataset contains 2687 photometric measurements, obtained between 78 minutes and

Edi Halyo

We describe cosmic D--term strings as D3 branes wrapped on a resolved conifold. The matter content that gives rise to D--term strings is shown to describe the world--volume theory of a space--filling D3 brane transverse to the conifold which itself is a wrapped D5 brane. We show that, in this brane theory, the tension of the wrapped D3 brane mathces that of

Raymond Y. Chiao, A. D. Speliotopoulos

It is shown that atom interferometry allows for the construction of MIGO, the Matter-wave Interferometric Gravitational-wave Observatory. MIGOs of the same sensitivity as LIGO or LISA are expected to be orders of magnitude smaller than either one. A design for MIGO using crystalline diffraction gratings is introduced, and its sensitivity is calculated.

Daniel Boer, Werner Vogelsang

We propose that back-to-back correlations in azimuthal angle of jets produced in collisions of unpolarized with transversely polarized proton beams could be used to determine Sivers functions. The corresponding single-spin asymmetry is not power-suppressed, but is subject to Sudakov suppression. We present estimates of the asymmetry (without and with Sudakov

A. T. Boothroyd, R. Coldea, D. A. Tennant, D. Prabhakaran

We present neutron scattering spectra taken from a single crystal of Na0.75CoO2, the precursor to a novel cobalt-oxide superconductor. The data contain a prominent inelastic signal at low energies (~10 meV), which is localized in wavevector about the origin of two-dimensional reciprocal space. The signal is highly dispersive, and decreases in intensity with

V. Oganesyan, Iddo Ussishkin

We examine the possibility that the large Nernst signal observed in the pseudogap regime of hole-doped cuprates originates from quasiparticle transport in a state with d-density wave (DDW) order, proposed by S. Chakravarty et al. [Phys. Rev. B 63, 094503 (2001)]. We find that the Nernst coefficient can be moderately enhanced in magnitude by DDW order, and is

C. A. Scrucca, M. Serone, L. Silvestrini, A. Wulzer

Six-dimensional orbifold models where the Higgs field is identified with some internal component of a gauge field are considered. We classify all possible T^2/Z_N orbifold constructions based on a SU(3) electroweak gauge symmetry. Depending on the orbifold twist, models with two, one or zero Higgs doublets can be obtained. Models with one Higgs doublet are p

Raymond Y. Chiao, Achilles D. Speliotopoulos

A dynamical, non-Euclidean spacetime geometry in general relativity theory implies the possibility of gravitational radiation. Here we explore novel methods of detecting such radiation from astrophysical sources by means of matter-wave interferometers (MIGOs), using atomic beams emanating from supersonic atomic sources that are further cooled and collimated

V. Greco, C. M. Ko, R. Rapp

We investigate effects of charm-quark interactions in a Quark-Gluon Plasma on the production of $D$ and $J/ψ$ mesons in high-energy heavy-ion collisions. Employing a previously constructed coalescence model that successfully reproduces the transverse momentum ($p_T$) spectra and elliptic flow ($v_2(p_T)$) of light hadrons at RHIC from underlying light-quark

Claus Diem, Gerhard Frey

For every odd prime number p, we give examples of non-constant smooth families of genus 2 curves over fields of characteristic p which have pro-Galois (pro-étale) covers of infinite degree with geometrically connected fibers. The Jacobians of the curves are isomorphic to products of elliptic curves.

I. A. Bandos, J. A. de Azcarraga, J. M. Izquierdo, M. Picon

We develop the BPS preon conjecture to analyze the supersymmetric solutions of D=11 supergravity. By relating the notions of Killing spinors and BPS preons, we develop a moving G-frame method (G=GL(32,R), SL(32,R) or Sp(32,R)) to analyze their associated generalized holonomies. As a first application we derive here the equations determining the generalized h

Cenke Xu, Joel E. Moore

The 2D quantum phase transition that occurs in a square lattice of $p+ip$ superconductors is used to show how four-body interactions in $d=2$ reproduce nonperturbative effects familiar from the study of two-body interactions in $d=1$. This model can be analyzed using an exact lattice self-duality of the associated 3D classical model; this duality is the 3D g

Adam K. Leibovich, Zoltan Ligeti, Iain W. Stewart, Mark B. Wise

We study nonleptonic Lambda_b -> Lambda_c pi, Sigma_c pi and Sigma_c^* pi decays in the limit m_b, m_c, E_pi >> Lambda_{QCD} using the soft-collinear effective theory. Here Sigma_c = Sigma_c(2455) and Sigma_c^* = Sigma_c(2520). At leading order the Lambda_b -> Sigma_c^{(*)} pi rates vanish, while the Lambda_b -> Lambda_c pi rate is related to Lambda_b -> Lam

Christian Stephan-Otto, Ken D. Olum, Xavier Siemens

We investigate the effects of cosmological expansion on the spectrum of small-scale structure on a cosmic string. We simulate the evolution of a string with two modes that differ in wavelength by one order of magnitude. Once the short mode is inside the horizon, we find that its physical amplitude remains unchanged, in spite of the fact that its comoving wav

Christian W. Bauer, Matthew P. Dorsten, Michael P. Salem

We consider matching from SCETI, which includes ultrasoft and collinear particles, onto SCETII with soft and collinear particles at one loop. Keeping the external fermions off their mass shell does not regulate all IR divergences in both theories. We give a new prescription to regulate infrared divergences in SCET. Using this regulator, we show that soft and

W. Forman, P. Nulsen, S. Heinz, F. Owen

We combined deep Chandra, ROSAT HRI, and XMM-Newton observations of M87 to study the impact of AGN outbursts on its gaseous atmosphere. Many X-ray features appear to be a direct result of repetitive AGN outbursts. In particular, the X-ray cavities around the jet and counter jet are likely due to the expansion of radio plasma, while rings of enhanced emission

Alfredo Herrera-Aguilar, Refugio Rigel Mora-Luna

In the framework of the 5D low-energy effective field theory of the heterotic string with no vector fields excited, we combine two non-linear methods in order to construct a solitonic field configuration. We first apply the inverse scattering method on a trivial vacuum solution and obtain an stationary axisymmetric two-soliton configuration consisting of a m

J. Harnad, I. Loutsenko, O. Yermolayeva

Finite-dimensional reductions of the 2D dispersionless Toda hierarchy, constrained by the ``string equation'' are studied. These include solutions determined by polynomial, rational or logarithmic functions, which are of interest in relation to the ``Laplacian growth'' problem governing interface dynamics. The consistency of such reductions i

Joke Adam, Jos Gheerardyn, Bert Janssen, Yolanda Lozano

We present an elegant method to prove the invariance of the Chern-Simons part of the non-Abelian action for N coinciding D-branes under the R-R and NS-NS gauge transformations, by carefully defining what is meant by a background gauge transformation in the non-Abelian world volume action. We study as well the invariance under massive gauge transformations of

ZEUS Collaboration

The photoproduction of beauty quarks in events with two jets and a muon has been measured with the ZEUS detector at HERA using an integrated luminosity of 110 pb$^{- 1}$. The fraction of jets containing b quarks was extracted from the transverse momentum distribution of the muon relative to the closest jet. Differential cross sections for beauty production a

Jian Qi Shen

Gravitomagnetic charge that can also be referred to as the {\it dual mass} or {\it magnetic mass} is the topological charge in gravity theory. A gravitomagnetic monopole at rest can produce a stationary gravitomagnetic field. Due to the topological nature of gravitomagnetic charge, the metric of spacetime where the gravitomagnetic matter is present will be n

Behrooz Mirzaii

The third homology group of GL_n(R) is studied, where R is a `ring with many units' with center Z(R). The main theorem states that if K_1(Z(R))_Q \simeq K_1(R)_Q, (e.g. R a commutative ring or a central simple algebra), then H_3(GL_2(R), Q) --> H_3(GL_3(R), Q) is injective. If R is commutative, Q can be replaced by a field k such that 1/2 is in k. For an

Sophie de Buyl, Marc Henneaux, Bernard Julia, Louis Paulot

We show how the properties of the cosmological billiards provide useful information (spacetime dimension and $p$-form spectrum) on the oxidation endpoint of the oxidation sequence of gravitational theories. We compare this approach to the other available methods: $GL(n,R)$ subgroups and the superalgebras of dualities.

Thomas Fischbacher

Values for the bulk Witten indices for D=10 Yang-Mills integrals for some regular simple groups of rank 4 and 5 are calculated by employing the BRST deformation technique by Moore, Nekrasov and Shatashvili. The results cannot be reconciled with the double assumption that the number of normalizable ground states is given by certain simple partition functions

Yuri Shtanov, Alexander Viznyuk

We study gravitational perturbations in the Randall-Sundrum two-brane background with scalar-curvature terms in the action for the branes, allowing for positive as well as negative bulk gravitational constant. In the zero-mode approximation, we derive the linearized gravitational equations, which have the same form as in the original Randall-Sundrum model bu

A. C. Johnson, C. M. Marcus, M. P. Hanson, A. C. Gossard

We investigate a tunable Fano interferometer consisting of a quantum dot coupled via tunneling to a one-dimensional channel. In addition to Fano resonance, the channel shows strong Coulomb response to the dot, with a single electron modulating channel conductance by factors of up to 100. Where these effects coexist, lineshapes with up to four extrema are fou

Stefan E. Müller

The measurement of hadronic cross sections at low centre-of-mass energies is currently attracting much interest because of the rô{}le these measurements play in the theoretical evaluation of the anomalous magnetic moment of the muon. The KLOE experiment at the DA$Φ$NE $ϕ$-factory in Frascati aims to determine the cross section of the dominant contribution $e

Sotaro Sasaki, Hiroaki Ikeda, Kosaku Yamada

We investigate pairing symmetry and a transition temperature in a quasi-one-dimensional repulsive Hubbard model. We solve the Eliashberg equation using the third-order perturbation expansion with respect to the on-site repulsion $U$. We find that when the electron number density is shifted from the half-filled, a transition into unconventional superconductiv

Peter Bouwknegt, David Ridout

The algebraic definition of charges for symmetry-preserving D-branes in Wess-Zumino-Witten models is shown to coincide with the geometric definition, for all simple Lie groups. The charge group for such branes is computed from the ambiguities inherent in the geometric definition.

S. S. Wu, H. X. Zhang, Y. J. Yao

In the hadrodynamics (QHD) there are two methods to take account of the contribution of negative-energy states in the relativistic random phase approximation (RRPA). Dawson and Furnstahl made the ansatz that the Dirac sea were empty, while according to the Dirac hole theory the sea should be fully occupied. The two methods seem contradictory. Their close rel

Edmond L Berger, Tao Han, Jing Jiang, Tilman Plehn

We compute the inclusive and differential cross sections for the associated production of a top quark along with a charged Higgs boson at hadron colliders to next-to-leading order (NLO) in perturbative quantum chromodynamics (QCD) and in supersymmetric QCD. For small Higgs boson masses we include top quark pair production diagrams with subsequent top quark d

M. Shifman, A. Yung

Building on our previous results, we study D-brane/string prototypes in weakly coupled (3+1)-dimensional supersymmetric field theory engineered to support (2+1)-dimensional domain walls, "non-Abelian" strings and various junctions. Our main but not exclusive task is the study of localization of non-Abelian gauge fields on the walls. The model we work

Joshua A. Faber, Philippe Grandclément, Frederic A. Rasio

We present the first results from our new general relativistic, Lagrangian hydrodynamics code, which treats gravity in the conformally flat (CF) limit. The evolution of fluid configurations is described using smoothed particle hydrodynamics (SPH), and the elliptic field equations of the CF formalism are solved using spectral methodsin spherical coordinates.

Tommy Grav, Matthew J. Holman

We present JHKs photometry of 10 Jovian and 4 Saturnian irregular satellites, taken with the Near-InfraRed Imager (NIRI) at the 8-m Gemini North Observatory on Mauna Kea, Hawaii. The observed objects have near-infrared colors consistent with C, P and D-type asteroids, although J XII Ananke and S IX Phoebe show weak indications of possible water features in t

M. W. Mitchell, J. S. Lundeen, A. M. Steinberg

Using a linear optical elements and post-selection, we construct an entangled polarization state of three photons in the same spatial mode. This state is analogous to a ``photon-number path entangled state'' and can be used for super-resolving interferometry. Measuring a birefringent phase shift, we demonstrate two- and three-fold improvements in pha

S. Albeverio, K. Chen, S. M. Fei

A new necessary separability criterion that relates the structures of the total density matrix and its reductions is given. The method used is based on the realignment method [K. Chen and L.A. Wu, Quant. Inf. Comput. 3, 193 (2003)]. The new separability criterion naturally generalizes the reduction separability criterion introduced independently in previous

Yehoshua Levinson

Electromagnetic field fluctuations are responsible for the destruction of electron coherence (dephasing) in solids and in vacuum electron beam interference. The vacuum fluctuations are modified by conductors and dielectrics, as in the Casimir effect, and hence, bodies in the vicinity of the beams can influence the beam coherence. We calculate the quenching o

Oľga Nánásiová, Andrei Yu. Khrennikov

We present a way of introducing joint distibution function and its marginal distribution functions for non-compatible observables. Each such marginal distribution function has the property of commutativity. Models based on this approach can be used to better explain some classical phenomena in stochastic processes.

T. Stehmann, W. D. Heiss, F. G. Scholtz

Two damped coupled oscillators have been used to demonstrate the occurrence of exceptional points in a purely classical system. The implementation was achieved with electronic circuits in the kHz-range. The experimental results perfectly match the mathematical predictions at the exceptional point. A discussion about the universal occurrence of exceptional po

Thomas Salzburger, Helmut Ritsch

We study motion and field dynamics of a single-atom laser consisting of a single incoherently pumped free atom moving in an optical high-{\it Q} resonator. For sufficient pumping, the system starts lasing whenever the atom is close to a field antinode. If the field mode eigenfrequency is larger than the atomic transition frequency, the generated laser light

Vasily E. Tarasov

Using Liouville space and superoperator formalism we consider pure stationary states of open and dissipative quantum systems. We discuss stationary states of open quantum systems, which coincide with stationary states of closed quantum systems. Open quantum systems with pure stationary states of linear oscillator are suggested. We consider stationary states

Yu-Ying Liu, Peng-Ye Wang, Shuo-Xing Dou, Wei-Chi Wang

Molecular combing is a powerful and simple method for aligning DNA molecules onto a surface. Using this technique combined with fluorescence microscopy, we observed that the length of lambda-DNA molecules was extended to about 1.6 times their contour length (unextended length, 16.2 micrometers) by the combing method on hydrophobic polymethylmetacrylate (PMMA

E. M. Drobyshevski

Numerous problems connected with an assumption of the life origin on the Earth do not arise on Galilean satellites. Here, in presence of a practically non-salt water and of a great deal (~5-10%) of abiogenic organics, a great diversity of conditions, which are unthinkable for the Earth, were realized more than once. They were caused by global electrochemical

A. Soubret, G. Berginc

A general approach for the calculation of the incoherent intensity scattered by a random medium with rough boundaries has been developed using a Green function formalism. The random medium consists of spherical particles whose physical repartition is described by a pair-distribution function. The boundary contribution is included in the Green functions with

N. Wermes, L. Andricek, P. Fischer, M. Haerter

DEPFET pixel detectors are unique devices in terms of energy and spatial resolution because very low noise (ENC = 2.2e at room temperature) operation can be obtained by implementing the amplifying transistor in the pixel cell itself. Full DEPFET pixel matrices have been built and operated for autoradiographical imaging with imaging resolutions of 4.3 +- 0.8

A. Christian Silva

This paper is the result of setting up GRENOUILLE in the Nonlinear Dynamics Laboratory at the University of Maryland at College Park. With the experience acquired in the process of setting up GRENOUILLE, this manual was compiled from literature and from hand-on experience to serve as a quick guide, a step-by-step help to construct GRENOUILLE and to understan

A. Soubret, G. Berginc

The problem of an electromagnetic wave scattered from a random medium layer with rough boundaries is formulated using integral equations which involve two kinds of Green functions. The first one describes the wave scattered by the random medium and the rough boundaries, and the second one which corresponds to the unperturbed Green functions describes the sca

Katja Klein

With a total area of 210 squaremeters and about 15000 single silicon modules the silicon strip tracker of the CMS experiment at the LHC will be the largest silicon strip detector ever built. While the performance of the individual mechanical and electronic components has already been tested extensively, their interplay in larger integrated substructures also

Ariel Caticha, Roland Preuss

The method of Maximum (relative) Entropy (ME) is used to translate the information contained in the known form of the likelihood into a prior distribution for Bayesian inference. The argument is guided by intuition gained from the successful use of ME methods in statistical mechanics. For experiments that cannot be repeated the resulting "entropic prior&

Larissa N. Ikryannikova, Leila Yu. Ustynyuk, Alexander N. Tikhonov

Imidazoline-based nitroxide radicals are often used as spin probes for medium acidity and polarity in different systems. In this work, using the density functional theory (DFT) approach, we have studied how physico-chemical characteristics (geometry, atomic charges and electron spin density distribution) of pH-sensitive spin label 4-amino-2,2,5,5-tetramethyl

Johannes M. Bauer

The electro-magnetic calorimeter at the BaBar detector, part of the asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with good resolution. The calorimeter is calibrated at the low energy end with 6.13 MeV photons obtained from a liquid source system. During the calibration, a fluorine-rich liquid is activated via a neut

L. Trache, F. Carstoiu, C. A. Gagliardi, R. E. Tribble

Existing experimental data for the breakup of 8B at energies from 30 to 1000 MeV/nucleon on light through heavy targets are analyzed in detail in terms of an extended Glauber model. The predictions of the model are in excellent agreement with independent reaction data (reaction cross sections and parallel momentum distributions for core like fragments). Fina

Qingfeng Li, Zhuxia Li, Enguang Zhao, H. Stoecker

The N/Z ratio of free nucleons from collisions of neutron-rich nuclei as a function of their momentum is studied by means of Isospin dependent Quantum Molecular Dynamics. We find that this ratio is not only sensitive to the form of the density dependence of the symmetry potential energy but also its strength determined by the symmetry energy coefficient. The

Qingfeng Li, Zhuxia Li, Enguang Zhao

The in-medium neutron-proton, proton-proton (neutron-neutron) elastic scattering cross sections ($σ_{np}^{*}$, $σ_{pp(nn)}^{*}$) are studied based on the effective Lagrangian of density dependent relativistic hadron theory in which the $δ$[$a_0(980)$] meson is included. Our study shows that at low densities the $σ_{np}^*$ is about 3-4 times larger than $σ_{p

H. Mineo, W. Bentz, N. Ishii, A. W. Thomas

Quark light cone momentum distributions in nuclear matter and the structure function of a bound nucleon are investigated in the framework of the Nambu-Jona-Lasinio model. This framework describes the nucleon as a relativistic quark-diquark state, and the nuclear matter equation of state by using the mean field approximation. The scalar and vector mean fields

Hans Feldmeier, Thomas Neff, Robert Roth

An ab-initio description of atomic nuclei that solves the nuclear many-body problem for realistic nuclear forces is expected to possess a high degree of predictive power. In this contribution we treat the main obstacle, namely the short-ranged repulsive and tensor correlations induced by the realistic nucleon-nucleon interaction, by means of a unitary correl

Benno Rumpf Alan C. Newell

Intermittent high-amplitude structures emerge in a damped and driven discrete nonlinear Schroedinger equation whose solutions transport both energy and particles from sources to sinks. These coherent structures are necessary for any solution that has statistically stationary transport properties.

Benno Rumpf

The localization of energy in the discrete nonlinear Schroedinger equation is explained with statistical methods. The partition function and the entropy of the system are computed for low-amplitude initial conditions. Detailed predictions for the long-time solution are derived.

Eugene Bogomolny, Charles Schmit

Multiplicities of periodic orbit lengths for non-arithmetic Hecke triangle groups are discussed. It is demonstrated both numerically and analytically that at least for certain groups the mean multiplicity of periodic orbits with exactly the same length increases exponentially with the length. The main ingredient used is the construction of joint distribution

Ricardo Lopez-Ruiz

The LMC complexity, an indicator of complexity based on a probabilistic description, is revisited. A straightforward approach allows us to establish the time evolution of this indicator in a near-equilibrium situation and gives us a new insight for interpreting the LMC complexity for a general non equilibrium system. Its relationship with the Renyi entropies

C. Jung, A. Emmanouilidou

A method is presented to construct a partition of an incomplete horseshoe in a Poincare map which is only based on unstable manifolds of outermost fixed points and eventually their limits. Thereby this partition becomes natural from the point of view of asymptotic scattering observations. The symbolic dynamics derived from this partition coincides with the o

Oliver Muelken, Henk van Beijeren

We analytically determine the dynamical properties of two dimensional field driven Lorentz gases within the thermodynamic formalism. For dilute gases subjected to an iso-kinetic thermostat, we calculate the topological pressure as a function of a temperature-like parameter $\ba$ up to second order in the strength of the applied field. The Kolmogorov-Sinai en

H. J. Shin

An application of the Darboux transformation on a cnoidal wave background in the coupled nonlinear Schrödinger equation gives a new solution which describes a soliton moving on a cnoidal wave. This is a generalized version of the previously known soliton solutions of dark-bright pair. Here a dark soliton resides on a cnoidal wave instead of on a constant bac

Alina Dobrogowska, Anatol Odzijewicz

By solving an infinite nonlinear system of $q$-difference equations one constructs a chain of $q$-difference operators. The eigenproblems for the chain are solved and some applications, including the one related to $q$-Hahn orthogonal polynomials, are discussed. It is shown that in the limit q->1 the present method corresponds to the one developed by Infeld

Pavel Exner, Sylwia Kondej

We discuss a generalized Schrödinger operator in $L^2(\mathbb{R}^d), d=2,3$, with an attractive singular interaction supported by a $(d-1)$-dimensional hyperplane and a finite family of points. It can be regarded as a model of a leaky quantum wire and a family of quantum dots if $d=2$, or surface waves in presence of a finite number of impurities if $d=3$. W

Zheng Huang

The sectional curvature of the Weil-Petersson metric on Teichmuller space is known to be negative. We show that this Weil-Petersson sectional curvature is not pinched from above by any negative constants, i.e., there is no negative upper bound.

N. J. A. Sloane, James A. Sellers

A partition n = p_1 + p_2 + ... + p_k with 1 <= p_1 <= p_2 <= ... <= p_k is called non-squashing if p_1 + ... + p_j <= p_{j+1} for 1 <= j <= k-1. Hirschhorn and Sellers showed that the number of non-squashing partitions of n is equal to the number of binary partitions of n. Here we exhibit an explicit bijection between the two families, and determine the num

Tim Bratten

In this paper we generalize the comparison theorem of Hecht and Taylor to arbitrary parabolic subalgebras of a complex reductive Lie algebra and then apply our generalized comparison theorem to obtain results about the geometric realization of representations in flag spaces.

Roman Sauer

There are notions of L^2-Betti numbers for discrete groups (Cheeger-Gromov, Lueck), for type II_1-factors (recent work of Connes-Shlyakhtenko) and for countable standard equivalence relations (Gaboriau). Whereas the first two are algebraically defined using Lueck&#39;s dimension theory,Gaboriau&#39;s definition of the latter is inspired by the work of Cheege

Behrooz Mirzaii

In this note the homology stability problem for hyperbolic unitary groups over a local ring with an infinite residue field is studied.

Roy Meshulam

Let G be a finite abelian group of order n. For a complex valued function f on G, let \fht denote the Fourier transform of f. The uncertainty inequality asserts that if f \neq 0 then |supp(f)| |supp(\fht)| \geq n. Answering a question of Terence Tao, the following improvement of the classical inequality is shown: Let d_1<d_2 be two consecutive divisors of n.

P. H. Kropholler, S. Mosheni Rajaei, J. Segal

We determine the rings of invariants in the symmetric algebra on the dual of a vector space V over the field of two elements, for the group G of orthogonal transformations preserving a non-singular quadratic form on V. The invariant ring is shown to have a presentation in which the difference between the number of generators and the number of relations is eq

Alan Horwitz

Let p(x) be a polynomial of degree 4 with four distinct real roots r1<r2<r3<r4. Let x1<x2<x3 be the critical points of p, and define the ratios s_{k}=((x_{k}-r_{k})/(r_{k+1}-r_{k})),k=1,2,3. For notational convenience, let s1=u, s2=v, and s3=w. (u,v,w) is called the ratio vector of p. We prove necessary and sufficient conditions for (u,v,w) to be a ratio vec

Alan Horwitz

Let R be a four-sided convex polygon in the xy plane and let M1 and M2 be the midpoints of the diagonals of R. It is well-known that if E is an ellipse inscribed in R, then the center of E must lie on Z, the open line segment connecting M1 and M2. We prove the converse: If (h,k) lies in Z, then there is a unique ellipse with center (h,k) inscribed in R. This

Ilia Itenberg, Viatcheslav Kharlamov, Eugenii Shustin

The invariance of the Welschinger numbers for real unnodal Del Pezzo surfaces, which we used for the enumeration of real rational curves on real toric Del Pezzo surfaces (see math.AG/0303378 and IMRN 49 (2003), 2639-2653), follows from J.-Y. Welschinger&#39;s theorem stated and proved in a symplectic setting (math.AG/0303145 and CRAS, Ser. I, 336 (2003), 341

Fioresi Rita

In this paper we compute explicit formulas for the commutation relations among quantum minors in the quantum matrix bialgebra $\cO_q(M_n(k))$.

Matthew Baker, Enrique Gonzalez-Jimenez, Josep Gonzalez, Bjorn Poonen

A curve X over the field Q of rational numbers is modular if it is dominated by X_1(N) for some N; if in addition the image of its jacobian in J_1(N) is contained in the new subvariety of J_1(N), then X is called a new modular curve. We prove that for each integer g at least 2, the set of new modular curves over Q of genus g is finite and computable. For the