August 2003 arXiv papers — page 24

Bertrand Bouriquet, Yasuhisa Abe, Grigori Kosenko

An extremely good reproduction of experimental excitation function of the 1n reactions producing Z=110,Z=111 and Z=112 is obtained by the two-step model and the statistical decay code KEWPIE. Thus, an extension of the recipe permits us to predict reliable values of the residue cross-sections of the elements Z=113 and Z=114 which will be a useful guide for pl

Yasuhisa Abe, Bertrand Bouriquet

Towards precise predictions of residue cross sections of the superheavy elements, recent theoretical developments of reaction mechanisms are presented, together with the remaining problems which give rise to ambiguities in absolute values of cross sections predicted.

R. Debbe

This paper presents recent results from the BRAHMS experiment at RHIC; including results on particle production in rapidity space extending from y=0 to y ~ 3 and on the transverse momentum distribution of fully identified charged particles. These results were obtained from the 5% most central Au-Au collisions recorded during RHIC Run-2 at sqrt{s_{NN}} = 200

Roberto Benzi, Alfonso Sutera

We study the mechanism of stochastic resonance in a two dimensional Landau Ginzburg equation perturbed by a white noise. We shortly review how to renormalize the equation in order to avoid ultraviolet divergences. Next we show that the renormalization amplifies the effect of the small periodic perturbation in the system. We finally argue that stochastic reso

Stephen Gustafson, Kenji Nakanishi, Tai-Peng Tsai

In this paper we study a class of nonlinear Schrödinger equations which admit families of small solitary wave solutions. We consider solutions which are small in the energy space $H^1$, and decompose them into solitary wave and dispersive wave components. The goal is to establish the asymptotic stability of the solitary wave and the asymptotic completeness o

Yuri Lvov Sergey Nazarenko Robert West

The kinetics of nonequilibrium Bose-Einstein condensates are considered within the framework of the Gross-Pitaevskii equation. A systematic derivation is given for weak small-scale perturbations of a steady confined condensate state. This approach combines a wavepacket WKB description with the weak turbulence theory. The WKB theory derived in this paper desc

J. Dimock

We consider open bosonic strings. The non-interacting multi-string theory is described by certain free string field operators which we construct. These are shown to have local commutators with respect to a center of mass coordinate. The construction is carried out both in the light cone gauge and in a covariant formulation.

Pietro Poggi-Corradini

A lot is known about the forward iterates of an analytic function which is bounded by 1 in modulus on the unit disk. The Denjoy-Wolff Theorem describes their convergence properties and several authors, from the 1880's to the 1980's, have provided conjugations which yield very precise descriptions of the dynamics. Backward-iteration sequences are of a

W. Ethan Duckworth

This paper provides new, relatively simple proofs of some important results about unipotent classes in simple linear algebraic groups. We derive the formula for the Jordan blocks of the Richardson class of a parabolic subgroup of a classical group. This result was originally due to Spaltenstein. Secondly, we derive, for good characteristic, the description o

Paul Balmer, Michel Matthey

The Isomorphism Conjectures are translated into the language of homotopical algebra, where they resemble Thomason's descent theorems.

Paul Balmer, Michel Matthey

We establish a general method to produce cofibrant approximations in the model category $U_S(C,D)$ of $S$-valued $C$-indexed diagrams with $D$-weak equivalences and $D$-fibrations. We also present explicit examples of such approximations. Here, $S$ is an arbitrary cofibrantly generated simplicial model category and $D\subset C$ are small categories. An appli

Anna Klebanov

We present a simple combinatorial method to encode 3-dimensional manifolds, based on their Heegaard diagrams. The notion of a Gauss diagram of a 3-manifold is introduced. We check the conditions for a Gauss diagram to represent a closed manifold and a manifold with boundary.

Gert K. Pedersen

It is shown that a fixed point of a completely positive map on a semi-finite von Neumann algebra must commute with the operators determining the map (the Lueders phenomenon) if the element is finite or has finite square.

Morten Skarsholm Risager

We prove that the modular symbols appropriately normalized and ordered have an asymptotical normal distribution for all cocompact subgroups of SL_2(R). We introduce hyperbolic Eisenstein series in order to calculate the moments of the modular symbols.

Andreas Cap, Jan Slovak, Vojtech Zadnik

All parabolic geometries, i.e. Cartan geometries with homogeneous model a real generalized flag manifold, admit highly interesting classes of distinguished curves. The geodesics of a projective class of connections on a manifold, conformal circles on conformal Riemannian manifolds, and Chern--Moser chains on CR--manifolds of hypersurface type are typical exa

Jeffrey Burdges

There is a longstanding conjecture, due to Gregory Cherlin and Boris Zilber, that all simple groups of finite Morley rank are simple algebraic groups. One of the major theorems in the area is Borovik's trichotomy theorem. The "trichotomy" here is a case division of the minimal counterexamples within odd type, i.e. groups with a divisibble connect

Genevieve Walsh

We investigate great circle links in the three-sphere, the class of links where each component is a great circle. Using the geometry of their complements, we classify such links up to five components. For any two-bridge knot complement, there is a finite cover that is the complement of a link of great circles in $S^3$. We show that for many two-bridge knots,

Sei-Qwon Oh

A class of Poisson algebras considered as a Poisson version of the multiparameter quantized coordinate rings of symplectic and Euclidean $2n$-spaces is constructed and the prime Poisson ideals and the symplectic ideals of these Poisson algebras are described. As a result, it is shown that the multiparameter quantized symplectic and Euclidean $2n$-spaces are

Rafe Mazzeo, Andras Vasy

Let $(M,g)$ be a globally symmetric space of noncompact type, of arbitrary rank, and $Δ$ its Laplacian. We prove the existence of a meromorphic continuation of the resolvent $(Δ-\ev)^{-1}$ across the continuous spectrum to a Riemann surface multiply covering the plane. The methods are purely analytic and are adapted from quantum $N$-body scattering.

Paul Balmer, Michel Matthey

Consider a cofibrantly generated model category $S$, a small category $C$ and a subcategory $D$ of $C$. We endow the category $S^C$ of functors from $C$ to $S$ with a model structure, defining weak equivalences and fibrations objectwise but only on $D$. Our first concern is the effect of moving $C$, $D$ and $S$. The main notion introduced here is the ``$D$-c

Shrawan Kumar, Bernhard Leeb, John J. Millson

We compute the generalized triangle inequalities explicitly for all rank 3 symmetric spaces. We find that for Sp(6) the corresponding polyhedral cone has 102 facets and 51 edges.

Jeffrey Brock, Kenneth Bromberg, Richard Evans, Juan Souto

Let N be a complete hyperbolic 3-manifold that is an algebraic limit of geometrically finite hyperbolic 3-manifolds. We show N is homeomorphic to the interior of a compact 3-manifold, or tame, if one of the following conditions holds: (1) N has non-empty conformal boundary, (2) N is not homotopy equivalent to a compression body, or (3) N is a strong limit of

E. Langmann, R. J. Szabo, K. Zarembo

We present the exact solution of a scalar field theory defined with noncommuting position and momentum variables. The model describes charged particles in a uniform magnetic field and with an interaction defined by the Groenewold-Moyal star-product. Explicit results are presented for all Green's functions in arbitrary even spacetime dimensionality. Vario

Joanna Domienik, Piotr Kosinski

We consider threshold production of arbitrary number of Higgs particles by fermion-antifermion pair. The nullification of amplitudes for the special case Higgs mass = 2 * fermion mass is explained in terms of hidden symmetry of the reduced effective dynamics.

B. Basu, P. Bandyopadhyay

Taking resort to Haldane's spherical geometry we can visualize fractional quantum Hall effect on the noncommutative manifold $M_4 \times Z_N$ with $N>2$ and odd. The discrete space leads to the deformation of symplectic structure of the continuous manifold such that the symplectic area is given by $\triangle p.\triangle q=2πm \hbar$ with $m$ an odd integ

Yi-Xin Chen, Mark D. Gould, Yao-Zhong Zhang

Based on Haldane's spherical geometrical formalism of two-dimensional quantum Hall fluids, the relation between the noncommutative geometry of $S^2$ and the two-dimensional quantum Hall fluids is exhibited. If the number of particles $N$ is infinitely large, two-dimensional quantum Hall physics can be precisely described in terms of the noncommutative U(

E. Sharpe

These notes are a writeup of lectures given at the twelfth Oporto meeting on ``Geometry, Topology, and Physics,'' and at the Adelaide workshop ``Strings and Mathematics 2003,'' primarily geared towards a physics audience. We review current work relating boundary states in the open string B model on Calabi-Yau manifolds to sheaves. Such relati

Yuri V. Kovchegov

We discuss expectations of saturation physics for various observables in heavy ion collisions. We show how simple saturation-inspired assumptions about particle production in heavy ion collisions lead to Kharzeev-Levin-Nardi model. Comparing this model to RHIC data on particle multiplicities we conclude that saturation effects may play an important role in p

T. G. Steele, D. Harnett, G. Orlandini

Gaussian sum-rules, which are related to a two-parameter Gaussian-weighted integral of a hadronic spectral function, are able to examine the possibility that more than one resonance makes a significant contribution to the spectral function. The Gaussian sum-rules, including instanton effects, for scalar gluonic and non-strange scalar quark currents clearly i

Bing An Li

It is found that in the SM the Ward-Takahashi(WT) identities of the axial-vector currents and the charged vector currents of fermions are invalid after spontaneous symmetry breaking. The spin-0 components of Z and W fields are revealed from the invalidity of these WT identities. The masses of these spin-0 components are at $10^{14}$GeV. They are ghosts. Ther

S. Zschocke, O. P. Pavlenko, B. Kampfer

Within the Borel QCD sum rule approach at finite baryon density we study the role of the four-quark condensates for the modifications of the vector mesons $ρ$, $ω$ and $ϕ$ in nuclear matter. We find that in-medium modifications of the $ρ$ and $ω$ mesons are essentially dominated by the dependence of the 4-quark condensate on the nucleon density. In particula

T. M. Aliev, V. Bashiry, M. Savci

The CP violating asymmetries in the (b -> d l^+ l^-) decay, when one of the leptons is polarized, is investigated using the most general form of the effective Hamiltonian. The sensitivity of the CP violating asymmetries on the new Wilson coefficients is studied.

T. Blazek, S. F. King, J. K. Parry

We examine the potentially very promising signal $B_s\to μ^{+}μ^{-}$ in supersymmetry with large $\tanβ$ in a {\em top-down} approach starting from the best fits of an SO(10)-like model studied recently. Our results go beyond minimal flavour violation investigated in previous works. We show that the absolute best fits provide a signal for $B_s\to μ^{+}μ^{-}$

W. Cassing, S. Juchem

In this article we study the time evolution of an interacting field theoretical system, i.e. ϕ^4-field theory in 2+1 space-time dimensions, on the basis of the Kadanoff-Baym equations for a spatially homogeneous system including the self-consistent tadpole and sunset self-energies. We find that equilibration is achieved only by inclusion of the sunset self-e

A. Samsonov

The magnetic moment of the rho-meson is calculated in the framework of QCD sum rules in external fields. Perturbative corrections are taken into account. Bare loop calculations (parton model) give the value 2.0. The nonperturbative effects (operators of dimension 6) result in negative contribution, whereas perturbative corrections -- positive one. The final

Jihn E. Kim

We present $Z_3$ orbifold compactifications of $E_8\times E_8^\prime$ heterotic string with three Wilson lines, resulting to the maximum number of SU(3) factors. Here, all the matter spectrums are in the SU(3) trits($\equiv $ three representations ${\bf 3,\bar 3,1}$) of the $SU(3)^8$ GUT. Using this information, we show how three family supersymmetric standa

Kaushik Bhattacharya, Avijit K. Ganguly

To one loop the effective neutrino photon interaction takes place through the vector-vector type and the axialvector-vector type amplitude. In this work we explicitly write down the form of the axialvector-vector amplitude to all orders in the external magnetic field in a medium. We then infer upon its zero external momentum limit which contributes to the ef

Tomohiro Inagaki

Characteristic features of dynamical symmetry breaking are investigated in Randall-Sundrum (RS) background. To study the influence of bulk fermion or bulk gauge field I consider a five-dimensional four-fermion interaction model and a non-Abelian gauge field theory as simple models where the chiral symmetry is broken down dynamically. Using a four-dimensional

Thomas Appelquist, Maurizio Piai, Robert Shrock

We study fermion masses and mixing angles, including the generation of a seesaw mechanism for the neutrinos, in extended technicolor (ETC) theories. We formulate an approach to these problems that relies on assigning right-handed $Q=-1/3$ quarks and charged leptons to ETC representations that are conjugates of those of the corresponding left-handed fermions.

Hanqing Zheng

We point out that a commonly used parameterization form to describe the $σ$ resonance is problematic by introducing a spurious singularity below two particle threshold, on the second sheet. The spurious singularity violates chiral symmetry and leads to sizable contribution when the resonance is light and broad -- as what happens to the $σ$ resonance, hence m

L3 Collaboration

Events stemming from the pair-production of Z bosons in e^+e^- collisions are studied using 217.4 pb^-1 of data collected with the L3 detector at centre-of-mass energies from 200 GeV up to 209 GeV. The special case of events with b quarks is also investigated. Combining these events with those collected at lower centre-of-mass energies, the Standard Model pr

J. Castineiras, I. P. Costa e Silva, G. E. A. Matsas

We study and look for similarities between the response rates $R^{\rm dS}(a_0, Λ)$ and $R^{\rm SdS}(a_0, Λ, M)$ of a static scalar source with constant proper acceleration $a_0$ interacting with a massless, conformally coupled Klein-Gordon field in (i) deSitter spacetime, in the Euclidean vacuum, which describes a thermal flux of radiation emanating from the

Jiri Bicak, Petr Hajicek

The Hamiltonian dynamics of two-component spherically symmetric null dust is studied with regard to the quantum theory of gravitational collapse. The components--the ingoing and outgoing dusts--are assumed to interact only through gravitation. Different kinds of singularities, naked or "clothed", that can form during collapse processes are described.

Enrico Franconi, Gabriel Kuper, Andrei Lopatenko, Luciano Serafini

In this paper we give a robust logical and computational characterisation of peer-to-peer database systems. We first define a pre- cise model-theoretic semantics of a peer-to-peer system, which allows for local inconsistency handling. We then characterise the general computa- tional properties for the problem of answering queries to such a peer-to- peer syst

Ronald I. Greenberg

This paper performs the analysis necessary to bound the running time of known, efficient algorithms for generating all longest common subsequences. That is, we bound the running time as a function of input size for algorithms with time essentially proportional to the output size. This paper considers both the case of computing all distinct LCSs and the case

Yuko Okamoto

In complex systems such as spin systems and protein systems, conventional simulations in the canonical ensemble will get trapped in states of energy local minima. We employ the generalized-ensemble algorithms in order to overcome this multiple-minima problem. Two well-known generalized-ensemble algorithms, namely, multicanonical algorithm and replica-exchang

L. V. Butov, L. S. Levitov, A. V. Mintsev, B. D. Simons

The macroscopic exciton rings observed in the photoluminescence (PL) patterns of excitons in coupled quantum wells (CQWs) are explained by a series of experiments and a theory based on the idea of carrier imbalance, transport and recombination. The rings are found to be a source of cold excitons with temperature close to that of the lattice. We explored stat

S. Mackowski, T. A. Nguyen, H. E. Jackson, L. M. Smith

We demonstrate a new method of measuring the exciton spin relaxation time in semiconductor nanostructures by continuous-wave photoluminescence. We find that for self-assembled CdTe quantum dots the degree of circular polarization of emission is larger when exciting polarized excitons into the lower energy spin state than in the case when the excitons are exc

Markus Schmid, Arno P. Kampf

We investigate the local density of states (LDOS) for non-interacting electrons in a hard wall ellipse in the presence of a single non-magnetic scattering center. Using a T-matrix analysis we calculate the local Green's function and observe a variety of quantum mirage effects for different impurity positions. Locating the impurity near positions with LDO

S. Mackowski, H. E. Jackson, L. M. Smith, J. Kossut

We show that CdMnTe self-assembled quantum dots can be formed by depositing a submonolayer of Mn ions over a ZnTe surface prior to deposition of the CdTe dot layer. Single dot emission lines and strongly polarized quantum dot photoluminescence in an applied magnetic field confirm the presence of Mn in individual quantum dots. The width of PL lines of the sin

Paul P. F. Wessels, Matthias Schmidt, Hartmut Löwen

We consider the Asakura-Oosawa model of hard sphere colloids and ideal polymers in contact with a porous matrix modeled by immobilized configurations of hard spheres. For this ternary mixture a fundamental measure density functional theory is employed, where the matrix particles are quenched and the colloids and polymers are annealed, i.e. allowed to equilib

Tulika Maitra, A. Taraphder

The magnetic and orbital orders for the bilayer manganites in the doping region $0.5 < x <1.0$ have been investigated from a model that incorporates the two $e_g$ orbitals at each Mn site, the inter-orbital Coulomb interaction and lattice distortions. The usual double exchange operates via the $e_g$ orbitals. It is shown that such a model reproduces much of

P. J. E. M. van der Linden, K. Behnia

We present a one-heater-two-thermometer set-up for measuring thermal conductivity and electric resistivity of a bulk sample at low temperatures down to 0.1 K and in magnetic fields up to 27 Tesla. The design overcomes the difficulties emerging in the context of large water-cooled resistive magnets.

Paula Havu, Ville Havu, Martti Puska, Risto Nieminen

We use the effective-mass approximation and the density-functional theory with the local-density approximation for modeling two-dimensional nano-structures connected phase-coherently to two infinite leads. Using the non-equilibrium Green&#39;s function method the electron density and the current are calculated under a bias voltage. The problem of solving for

J. Merino, O. Gunnarsson

A simple model is introduced to describe conductance measurements between a scanning tunneling microscope (STM) tip and a noble metal surface with adsorbed transition metal atoms which display the Kondo effect. The model assumes a realistic parameterization of the potential created by the surface and a d3z2-r2 orbital for the description of the adsorbate. Fa

Hikaru Kawamura, Hitoshi Yonehara

The spin and the chirality orderings of the Heisenberg spin glass in two dimensions with the nearest-neighbor Gaussian coupling are investigated by equilibrium Monte Carlo simulations. Particular attention is paid to the behavior of the spin and the chirality correlation lengths. In order to observe the true asymptotic behavior, fairly large system size L\gs

M. Schmidt, W. Ratcliff, P. G. Radaelli, K. Refson

The transition metal spinel MgTi$_2$O$_4$ undergoes a metal-insulator transition on cooling below $T_{M-I} = 260$ K. A sharp reduction of the magnetic susceptibility below $T_{M-I}$ suggests the onset of a magnetic singlet state. Using high-resolution synchrotron and neutron powder diffraction, we have solved the low-temperature crystal structure of MgTi$_2$

Kazue Kudo, Tetsuo Deguchi

The level-spacing distributions of XXZ spin chains with next-nearest-neighbor couplings are studied under periodic boundary conditions. We confirm that integrable XXZ spin chains mostly have the Poisson distribution as expected. On the contrary, the level-spacing distributions of next-nearest-neighbor coupled XXZ chains are given by non-Wigner distributions.

Andras Suto

We study condensation of trapped bosons in the limit when the number of particles tends to infinity. For the noninteracting gas we prove that there is no phase transition in any dimension, but in any dimension at any temperature the system is 100% condensated into the one-particle ground state. In the case of an interacting gas we show that for a family of s

Jean-Loic Kneur, Marcus B. Pinto, Rudnei O. Ramos

We investigate the convergence properties of optimized perturbation theory, or linear $δ$ expansion (LDE), within the context of finite temperature phase transitions. Our results prove the reliability of these methods, recently employed in the determination of the critical temperature T_c for a system of weakly interacting homogeneous dilute Bose gas. We car

Albert Kong

We present the results of an XMM-Newton observation of the starburst galaxy IC342. Thirty-seven X-ray point sources were detected down to a luminosity limit of $\sim 10^{37}$ \lum. Most of the sources are located near the spiral arms. The X-ray point source luminosity function is consistent with a power-law shape with a slope of 0.55, typical of starburst ga

Hongguang Bi, Li-zhi Fang, Longlong Feng, Yipeng Jing

We study the baryonic gas clouds (the IGM) in the universe before the reionization with the lognormal model which is shown to be dynamcially legitimate in describing the fluctuation evolution in quasilinear as well as nonlinear regimes in recent years. The probability distribution function of the mass field in the LN model is long tailed and so plays an impo

K. Tyler, A. C. Quillen, A. La Page, G. H. Rieke

We compare the soft diffuse X-ray emission from Chandra images of 12 nearby intermediate inclination spiral galaxies to the morphology seen in Halpha, molecular gas, and mid-infrared emission. We find that diffuse X-ray emission is often located along spiral arms in the outer parts of spiral galaxies but tends to be distributed in a rounder morphology in the

Tamara Bogdanovic, Jian Ge, Claire E. Max, Lynne M. Raschke

We have obtained adaptive optics, high spatial resolution (0.15 arcsecond) K-band spectra and images of the region around the two active nuclei in NGC 6240 which show the presence of circumnuclear shocks. The data are consistent with the thermal excitation mechanism being the dominant one in the nuclear region. UV fluorescence and associative detachment may

Miguel F. Morales

The Milagro telescope monitors the northern sky for 100 GeV - 100 TeV transient emission through continuous very high energy wide-field observations. The large effective area and low energy threshold of Milagro allow it to detect very high energy gamma-ray burst emission with much higher sensitivity than previous instruments, and a fluence sensitivity at TeV

Gang Chen, J. Richard Gott, Bharat Ratra

We construct the error distribution of Hubble constant ($H_0$) measurements from Huchra&#39;s compilation of 461 measurements of $H_0$ and the WMAP experiment central value $H_0$ = 71 km s$^{-1}$ Mpc$^{-1}$. This error distribution is non-Gaussian, with significantly larger probability in the tails of the distribution than predicted by a Gaussian distributio

M. P. Redman, S. Viti, P. Cau, D. A. Williams

We study the chemistry in the slow wind during the transition from AGB star to pre-planetary nebula (PPN) and planetary nebula (PN). We show that there is a very rich chemistry of degradation products created by photoprocessing, driven by the gradually hardening radiation field of the central star. Most of these products are, however, photodissociated during

D. Pierini, C. C. Popescu, R. J. Tuffs, H. J. Voelk

We present the correlation between the far-infrared (FIR) and radio emissions from a composite sample of 72 nearby normal galaxies observed with the ISOPHOT instrument on board the Infrared Space Observatory. The galaxies in the sample have measurements at three FIR wavelengths (60, 100 and 170 micron), which allowed a direct determination of the warm and co

X. H. Li, J. L. Han

The low-frequency profiles of some pulsars manifest temporal broadening due to scattering, usually accompanied by flat polarization position angle (PA) curves. Assuming that the scattering works on the 4 Stokes parameters in the same way, we have simulated the effect of scattering on polarization profiles and find that the scattering can indeed flatten the P

A. Arellano Ferro, Sunetra Giridhar

We find the star HD 34700 to be a double-lined spectroscopic binary. We also identify it as a weak-line T Tauri object The spectra of both components are very similar and both show the Li I feature at 6708 Å. Strong arguments in favour of the binary nature of the star as opposed to other possibilities are offered. It is very likely that the companion is also

Joshua N. Winn, Patrick B. Hall, Paul L. Schechter

Gravitational lensing is a potentially important probe of spiral galaxy structure, but only a few cases of lensing by spiral galaxies are known. We present Hubble Space Telescope and Magellan observations of the two-image quasar PMN J2004-1349, revealing that the lens galaxy is a spiral galaxy. One of the quasar images passes through a spiral arm of the gala

Andrea Lionetto

We present a short review of the status of the dark matter problem. In particular we show that one of the best motivated candidate for the dark matter is the neutralino, a supersymmetric particle. Finally we study the possibility to detect gamma rays coming from neutralino pair annihilations that take place in our Galactic Center with the upcoming satellite

E. M. Schlegel, S. S. Holt, R. Petre

This paper describes the {\it Chandra} observation of the diffuse emission in the face-on spiral NGC 6946. Overlaid on optical and H$α$ images, the diffuse emission follows the spiral structure of the galaxy. An overlay on a 6 cm polarized radio intensity map confirms the phase offset of the polarized emission. We then extract and fit the spectrum of the unr

X. Dupac, J. -P. Bernard, N. Boudet, M. Giard

We present results obtained with the PRONAOS balloon-borne experiment on interstellar dust. In particular, the submillimeter / millimeter spectral index is found to vary between roughly 1 and 2.5 on small scales (3.5&#39; resolution). This could have implications for component separation in Cosmic Microwave Background maps.

F. -J. Zickgraf

High resolution line profiles are presented for selected forbidden and permitted emission lines of a sample of galactic B[e]-type stars. The spectral resolution corresponds to 5-7 km/s with the exception of some line profiles which were observed with a resolution of 9-13 km/s. All Ha profiles are characterized by a narrow split or single emission component w

T. Kato

From the observations reported to VSNET, we detected short fading episodes in two dwarf novae, RX And (orbital period 5.0 hr) and SU UMa (orbital period 1.8 hr). The episodes in RX And can be naturally explained as the response to a short-term reduction of the mass-transfer rate. A qualitative comparison with VY Scl-type fadings is also discussed. In SU UMa,

M. D. Ding, Q. R. Chen, J. P. Li, P. F. Chen

We perform a multi-wavelength study of a two-ribbon flare on 2002 September 29 and its associated filament eruption, observed simultaneously in the H-alpha line by a ground-based imaging spectrograph and in hard X-rays by RHESSI. The flare ribbons contain several H-alpha bright kernels that show different evolutional behaviors. In particular, we find two ker

Hee-Won Lee, Young-Jong Sohn, Young Woon Kang, Ho-Il Kim

We present a spectrum of the symbiotic star V1016 Cyg observed with the 3.6 m Canada-France-Hawaii Telescope, in order to illustrate a method to measure the covering factor of the neutral scattering region around the giant component with respect to the hot emission region around the white dwarf component. In the spectrum, we find broad wings around H$α$ and

Hee-Won Lee

We investigate the asymmetry of the scattering cross section of radiation around Ly$α$ by atomic hydrogen, which may be applied to analyses of scattering media with high column neutral hydrogen densities including damped Ly$α$ absorption systems of quasars. The exact scattering cross section is given by the Kramers-Heisenberg formula obtained from the fully

M. Viel, M. G. Haehnelt, R. F. Carswell, T. -S. Kim

We demonstrate that the lyman alpha forest flux power spectrum of ``randomised&#39;&#39; QSO absorption spectra is comparable in shape and amplitude to the flux power spectrum of the original observed spectra. In the randomised spectra a random shift in wavelength has been added to the observed absorption lines as identified and fitted with VPFIT. At 0.03 s/

Bruno Nachtergaele, Wolfgang Spitzer, Shannon Starr

We study a natural conjecture regarding ferromagnetic ordering of energy levels in the Heisenberg model which complements the Lieb-Mattis Theorem of 1962 for antiferromagnets: for ferromagnetic Heisenberg models the lowest energies in each subspace of fixed total spin are strictly ordered according to the total spin, with the lowest, i.e., the ground state,

P. Midodashvili, L. Midodashvili

We present a new 3-brane solution to Einstein&#39;s equations in (1+5)-spacetime with a negative bulk cosmological constant. This solution is a stringlike defect solution with decreasing scale function approaching a finite non-zero value in the radial infinity. It is shown that all local fields are localized on the brane only through the gravitational intera

William Gordon Ritter

We give a mathematically rigorous construction of the moduli space and vacuum geometry of a class of quantum field theories which are N=2 supersymmetric Wess-Zumino models on a cylinder. These theories have been proven to exist in the sense of constructive quantum field theory, and they also satisfy the assumptions used by Vafa and Cecotti in their study of

M. Enjalran, M. J. P. Gingras, Y. -J. Kao, A. Del Maestro

The pyrochlore antiferromagnet Tb2Ti2O7 has proven to be an enigma to experimentalists and theorists working on frustrated magnetic systems. The experimentally determined energy level structure suggests a local <111> Ising antiferromagnet at low temperatures, T < 10 K. An appropriate model then predicts a long-range ordered Q = 0 state below approximately 2

Viqar Husain, Oliver Winkler

We study constrained Hamiltonian systems by utilizing general forms of time discretization. We show that for explicit discretizations, the requirement of preserving the canonical Poisson bracket under discrete evolution imposes strong conditions on both allowable discretizations and Hamiltonians. These conditions permit time discretizations for a limited cla

Kaustubh Agashe, Antonio Delgado, Michael J. May, Raman Sundrum

We study precision electroweak constraints within a RS1 model with gauge fields and fermions in the bulk. The electroweak gauge symmetry is enhanced to SU(2)_L \times SU(2)_R \times U(1)_{B-L}, thereby providing a custodial isospin symmetry sufficient to suppress excessive contributions to the T parameter. We then construct complete models, complying with al

Igor Mencattini, Dirk Kreimer

We prove that insertion-elimination Lie algebra of Feynman graphs, in the ladder case, has a natural interpretation in terms of a certain algebra of infinite dimensional matrices. We study some aspects of its representation theory and we discuss some relations with the representation of the Heisenberg algebra

Carlo Ewerz, Volker Schatz

We compute the perturbative one-to-three Pomeron vertex in the colour glass condensate using the extended generalized leading logarithmic approximation in high energy QCD. The vertex is shown to be a conformal four-point function in two-dimensional impact parameter space. Our result can be used to compare different theoretical descriptions of the colour glas

Mitsuru Hamada

After Mayers (1996, 2001) gave a proof of the security of the Bennett-Brassard 1984 (BB84) quantum key distribution protocol, Shor and Preskill (2000) made a remarkable observation that a Calderbank-Shor-Steane (CSS) code had been implicitly used in the BB84 protocol, and suggested its security could be proven by bounding the fidelity, say F(n), of the incor

Csaba Csaki, Christophe Grojean, Luigi Pilo, John Terning

We present a 5D gauge theory in warped space based on a bulk SU(2)_L x SU(2)_R x U(1)_(B-L) gauge group where the gauge symmetry is broken by boundary conditions. The symmetry breaking pattern and the mass spectrum resembles that in the standard model (SM). To leading order in the warp factor the rho parameter and the coupling of the Z (or equivalently the S

D. Bazeia, C. Furtado, A. R. Gomes

We deal with scalar field coupled to gravity in five dimensions in warped geometry. We investigate models described by potentials that drive the system to support thick brane solutions that engender internal structure. We find analytical expressions for the brane solutions, and we show that they are all linearly stable.

Tzu-Chieh Wei, Joseph B. Altepeter, Paul M. Goldbart, William J. Munro

Bound entangled states are states that are entangled but from which no entanglement can be distilled if all parties are allowed only local operations and classical communication. However, in creating these states one needs nonzero entanglement resources to start with. Here, the entanglement of two distinct multipartite bound entangled states is determined an

F. A. Bovino, A. M. Colla, G. Castagnoli, S. Castelletto

We experimentally implemented an eavesdropping attack against the Ekert protocol for quantum key distribution based on the Wigner inequality. We demonstrate a serious lack of security of this protocol when the eavesdropper gains total control of the source. In addition we tested a modified Wigner inequality which should guarantee a secure quantum key distrib

Antonio C. da Silva, Scott T. Kay, Andrew R. Liddle, Peter A. Thomas

The Sunyaev-Zel&#39;dovich effect is a powerful new tool for finding and studying clusters at high redshift, particularly in combination with their X-ray properties. In this paper we quantify the expected scaling relations between these properties using numerical simulations with various models for heating and cooling of the cluster gas. For a Non-radiative

Andrew J. Kerman, Jeremy M. Sage, Sunil Sainis, David DeMille

We have produced ultracold, polar RbCs* molecules via photoassociation in a laser-cooled mixture of Rb and Cs atoms. Using a model of the RbCs* molecular interaction which reproduces the observed rovibrational structure, we infer decay rates in our experiments into deeply bound singlet ground state RbCs vibrational levels as high as 5 x 10^5 s^-1 per level.

Ch. Hartinger, F. Mayr, J. Deisenhofer, A. Loidl

We present detailed optical measurements of the mid-infrared (MIR) excitations in thin films of La2/3Sr1/3MnO3 (LSMO) and La2/3Ca1/3MnO3 (LCMO) across the magnetic transition. The shape of the excitation at about 0.2 eV in both samples is analyzed in terms of polaron models. We propose to identify the MIR resonance in LSMO as the excitation of large polarons

M. Guainazzi, P. Grandi, A. Comastri, G. Matt

We present results from a BeppoSAX (July 2001) observation of the FRI radio galaxy NGC6251, together with a re-analysis of archival ASCA (October 1994) and Chandra (September 2000) data. The weak detection above 10 keV and the lack of iron fluorescent K-alpha emission lines in the BeppoSAX spectrum rule out that the bulk of the X-ray emission is due to an ob

Murat M. Kaskulov, Peter Grabmayr

Considering the nucleon as a system of confined valence quarks surrounded by pions we derive a Galster-like parameterization of the neutron electric form factor $G_E^n$. Furthermore, we show that the proposed parameterization can be linked to properties of the pion cloud. By this, the high quality data for the pion form factor can be used in predictions of $

N. Kolev, M. N. Iliev, V. N. Popov, M. Gospodinov

The Raman spectra of CaFe2O4 were measured with several exact scattering configurations between 20 and 520K and the symmetry of all observed Raman lines was determined. The Ag and B2g lines were assigned to definite phonon modes by comparison to the results of lattice dynamical calculations. No anomaly of phonon parameters was observed near the magnetic orde

E. Bauer, G. Hilscher, H. Michor, Ch. Paul

$\rm CePt_3Si$ is a novel heavy fermion superconductor, crystallising in the $\rm CePt_3B$ structure as a tetragonally distorted low symmetry variant of the $\rm AuCu_3$ structure type. $\rm CePt_3Si$ exhibits antiferromagnetic order at $T_N \approx 2.2$ K and enters into a heavy fermion superconducting state at $T_c \approx 0.75$ K. Large values of $H_{c2}&