arXiv papers from August 2006

Héctor Cancela, Ernesto Mordecki

We give an estimate of the number of geometrically distinct open tours $\G$ for a knight on a chessboard. We use a randomization of Warnsdorff rule to implement importance sampling in a backtracking scheme, correcting the observed bias of the original rule, according to the proposed principle that ``most solutions follow Warnsdorff rule most of the time''. A

L. L. Avramov, R. -O. Buchweitz, S. B. Iyengar, C. Miller

It is proved that the sum of the Loewy lengths of the homology modules of a finite free complex F over a local ring R is bounded below by a number depending only on R. This result uncovers, in the structure of modules of finite projective dimension, obstructions to realizing R as a closed fiber of some flat local homomorphism. Other applications include, as

Karel A. van der Hucht

This paper gathers, from the literature and private communication, 72 new Galactic Population I Wolf-Rayet stars and 17 candidate WCLd stars, recognized and/or discovered after the publication of The VIIth Catalogue of Galactic Wolf-Rayet Stars. This brings the total number of known Galactic Wolf-Rayet stars to 298, of which 24 (8%) are in open cluster Weste

Peter Friz, Nicolas Victoir

We consider uniformly subelliptic operators on certain unimodular Lie groups of polynomial growth. It was shown by Saloff-Coste and Stroock that classical results of De Giorgi, Nash, Moser, Aronson extend to this setting. It was then observed by Sturm that many proofs extend naturally to the setting of locally compact Dirichlet spaces. We relate these result

Masanori Nakamura, Hui Li, Shengtai Li

Stability properties of ``magnetic tower'' jets propagating in the gravitationally stratified background have been examined by performing three-dimensional magnetohydrodynamic simulations. The current-carrying, Poynting flux-dominated magnetic tower jet, which possesses a highly wound helical magnetic field, is subject to the current-driven instability (CDI)

Pavel Etingof, Ching-Hwa Eu

We calculate the additive structure (together with the grading) of the Hochschild homology and cohomology and the cyclic homology of preprojective algebras of types ADE.

Reinoud J. Slagter

We present a numerical solution of a stationary 5-dimensional spinning cosmic string in the Einstein-Yang-Mills (EYM) model, where the extra bulk coordinate $\psi$ is periodic. It turns out that when $g_{\psi\psi}$ approaches zero, i.e., a closed time-like curve (CTC) would appear, the solution becomes singular. When a negative cosmological constant is incor

L. Tresse, O. Ilbert, E. Zucca, G. Zamorani

We present the evolution of the comoving SFR density in the redshift range 0 < z < 5 using the first epoch data release of the VVDS, that is 11564 spectra selected at I_AB=24 over 2200 arcmin^2 in two fields of view, the VVDS-0226-04 and the VVDS-CDFS-0332-27, and the cosmological parameters (Omega_M, Omega_L, h)=(0.3, 0.7, 0.7). We study the multi-wavelengt

M. Cavaglia, R. Godang, L. Cremaldi, D. Summers

We present a new Fortran Monte Carlo generator to simulate black hole events at CERN's Large Hadron Collider. The generator interfaces to the PYTHIA Monte Carlo fragmentation code. The physics of the BH generator includes, but not limited to, inelasticity effects, exact field emissivities, corrections to semiclassical black hole evaporation and gravitational

Michael Farber, Dirk Schuetz

This paper studies the homotopy invariant $\cat(X,\xi)$ introduced in \cite{farbe2}. Given a finite cell-complex $X$, we study the function $\xi\mapsto \cat(X,\xi)$ where $\xi$ varies in the cohomology space $H^1(X;\R)$. Note that $\cat(X,\xi)$ turns into the classical Lusternik - Schnirelmann category $\cat(X)$ in the case $\xi=0$. Interest in $\cat(X,\xi)$

Arthur Jaffe, Gordon Ritter

We give a mathematical construction of Euclidean quantum field theory on certain curved backgrounds. We focus on generalizing Osterwalder-Schrader quantization, as these methods have proved useful to establish estimates for interacting fields on flat space-times. In this picture, a static Killing vector generates translations in Euclidean time, and physical

Lior M. Burko, Gaurav Khanna

The accuracy of time-domain solutions of the inhomogeneous Teukolsky equation is improved significantly. Comparing energy fluxes in gravitational waves with highly accurate frequency-domain results for circular equatorial orbits in Schwarzschild and Kerr, we find agreement to within 1% or better, which we believe can be even further improved. We apply our me

Michael Farber, Dirk Schuetz

We prove that nonvanishing of the first Novikov-Betti number implies that the fundamental group contains a nonabelian free subgroup.

J. R. Mureika

The fractal dimension of large-scale galaxy clustering has been demonstrated to be roughly $D_F \sim 2$ from a wide range of redshift surveys. If correct, this statistic is of interest for two main reasons: fractal scaling is an implicit representation of information content, and also the value itself is a geometric signature of area. It is proposed that the

O. S. Duarte, A. O. Caldeira

We use the system-plus-reservoir approach to study the dynamics of a system composed of two independent Brownian particles. We present an extension of the well-known model of a bath of oscillators which is capable of inducing an effective coupling between the two particles depending on the choice made for the spectral function of the bath oscillators. The co

Samuel A. Kutin

We give a new ``nested adds'' circuit for implementing Shor's algorithm in linear width and quadratic depth on a nearest-neighbor machine. Our circuit combines Draper's transform adder with approximation ideas of Zalka. The transform adder requires small controlled rotations. We also give another version, with slightly larger depth, using only reversible cla

Tanguy Pallaver, Helmut Kroger, Marc Parizeau

Variants of the Kohonen model are proposed to study biological principles of self-organization in a model of young brain. We suggest a function to measure aquired knowledge and use it to auto-adapt the topology of neuronal connectivity, yielding substantial organizational improvement relative to the standard model. In the early phase of organization with mos

Yosuke Mizuno, Ken-Ichi Nishikawa, Shinji Koide, Philip Hardee

We have developed a new three-dimensional general relativistic magnetohydrodynamic (GRMHD) code, RAISHIN, using a conservative, high resolution shock-capturing scheme. The numerical fluxes are calculated using the Harten, Lax, & van Leer (HLL) approximate Riemann solver scheme. The flux-interpolated, constrained transport scheme is used to maintain a diverge

Vladimir L. Popov

For a connected semisimple algebraic group $G$, we consider some special infinite series of tensor products of simple $G$-modules whose $G$-fixed point spaces are at most one-dimensional. We prove that their existence is closely related to the existence of open $G$-orbits in multiple flag varieties and address the problem of classifying such series.

Hael Collins, R. Holman

We renormalize the divergences in the energy-momentum tensor of a scalar field that begins its evolution in an effective initial state. The effective initial state is a formalism that encodes the signatures of new physics in the structure of the quantum state of a field; in an inflationary setting, these signatures could include trans-Planckian effects. We t

Fergal P. Casey, Joshua J. Waterfall, Ryan N. Gutenkunst, Christopher R. Myers

We demonstrate the use of a variational method to determine a quantitative lower bound on the rate of convergence of Markov Chain Monte Carlo (MCMC) algorithms as a function of the target density and proposal density. The bound relies on approximating the second largest eigenvalue in the spectrum of the MCMC operator using a variational principle and the app

Bruno Vallette

In this article we give a conceptual definition of Manin products in any category endowed with two coherent monoidal products. This construction can be applied to associative algebras, non-symmetric operads, operads, colored operads, and properads presented by generators and relations. These two products, called black and white, are dual to each other under

P Jacob, P. Mathieu

A bijection is presented between (1): partitions with conditions $f_j+f_{j+1}\leq k-1$ and $ f_1\leq i-1$, where $f_j$ is the frequency of the part $j$ in the partition, and (2): sets of $k-1$ ordered partitions $(n^{(1)}, n^{(2)}, ..., n^{(k-1)})$ such that $n^{(j)}_\ell \geq n^{(j)}_{\ell+1} + 2j$ and $ n^{(j)}_{m_j} \geq j+ {\rm max} (j-i+1,0)+ 2j (m_{j+1

A. Donkov, A. V. Chubukov

Motivated by the achievements of the $X$-ray scattering technique, we analyzed the profile of the light scattering intensity $R(q, \omega)$ at a finite $q$ in a 2D Heisenberg antiferromagnet. Previous Raman scattering studies at $q=0$ identified the two-magnon peak in $B_{1g}$ scattering geometry. We found that the $B_{1g}$ peak disperses downwards at a fini

E. Sasioglu, L. M. Sandratskii, P. Bruno

The magnetic phase diagram of the Mn-based semi-Heusler alloys is determined at T=0 using first-principles calculations in conjunction with the frozen-magnon approximation. We show that the magnetism in these systems strongly depends on the number of conduction electrons, their spin polarization and the position of the unoccupied Mn 3d states with respect to

D. R. Ballantyne, Y. Shi, G. H. Rieke, J. L. Donley

Deep X-ray surveys by Chandra and XMM-Newton have resolved about 80% of the 2-10 keV cosmic extragalactic X-ray background (CXRB) into point sources, the majority of which are obscured AGN. The obscuration might be connected to processes within the host galaxy, possibly the star-formation rate. Here, we use the results of CXRB synthesis calculations as input

Andrew A. West, John J. Bochanski, Suzanne L. Hawley, Kelle L. Cruz

We present a spectroscopic study and dynamical analysis of ~2600 M7 dwarfs. We confirm our previous finding that the fraction of magnetically active stars decreases with vertical distance from the Galactic plane. We also show that the mean luminosity of the H-alpha emission has a small but statistically significant decrease with distance. Using space motions

Ralph C. Bohlin

Free of any atmospheric contamination, HST provides the best available spectrophotometry from the far-UV to the near-IR for stars as faint as V~16. The HST CALSPEC standard star network is based on 3 standard candles: the hot, pure hydrogen white dwarf (WD) stars G191B2B, GD153, and GD71, which have Hubeny NLTE model flux calculations that require the atomic

Xiaofeng Tan

A novel theoretical method is developed to study the polycyclic aromatic hydrocarbon - diffuse interstellar band (PAH-DIB) hypothesis. In this method, a computer program is used to enumerate all PAH molecules with up to a specific number of fused benzene rings. Fast quantum chemical calculations are then employed to calculate the electronic transition energi

Samuel T. Lisi

This paper introduces techniques of symplectic topology to the study of homoclinic orbits in Hamiltonian systems. The main result is a strong generalization of homoclinic existence results due to Sere and to Coti-Zelati, Ekeland and Sere, which were obtained by variational methods. Our existence result uses a modification of a construction due to Mohnke (ori

Michael C. Ricci, Hua Xu, Ruslan Prozorov, Alexander P. Zhuravel

Metamaterials are artificial structures with unique electromagnetic properties, such as relative dielectric permittivity and magnetic permeability with values less than 1, or even negative. Because these properties are so sensitive to loss, we have developed metamaterials comprised of superconducting waveguides, wires, and split-ring resonators. An important

Arun Paramekanti, J. B. Marston

The study of SU(N) quantum spin models is relevant to a variety of physical systems including ultracold atoms in optical lattices, and also leads to insights into novel quantum phases and phase transitions of SU(2) spin models. We use Gutzwiller projected fermionic variational wavefunctions to explore the phase diagram and correlation functions of SU(N) spin

Laura DeMarco

Let $\MP_d$ denote the space of polynomials $f: \C \to \C$ of degree $d\geq 2$, modulo conjugation by $\Aut(\C)$. Using properties of polynomial trees (as introduced in [DM, math.DS/0608759]), we show that if $f_n$ is a divergent sequence of polynomials in $\MP_d$, then any subsequential limit of the measures of maximal entropy $m(f_n)$ will have finite supp

Michel Provansal, Peter Monkewitz

Vortex Shedding Dynamics in the Laminar Wake of Cones Michel Provansal1 and Peter A. Monkewitz1,2 1 IRPHE Aix-Marseille Universit\'{e}s FRANCE 2LMF, EPFL, SWITZERLAND Experiments on two cones of different taper ratios have been performed in the periodic Reynolds number range between 40 and 180. The visualizations of the plan view of the wake with hydrogen bu

Josef Pradler, Frank Daniel Steffen

Considering gravitino dark matter scenarios, we obtain the full gauge-invariant result for the relic density of thermally produced gravitinos to leading order in the Standard Model gauge couplings. For the temperatures required by thermal leptogenesis, we find gaugino mass bounds which will be probed at future colliders. We show that a conceivable determinat

Alessandro Strumia

We discuss how leptogenesis can explain the observed baryon asymmetry and summarize attempts of testing leptogenesis. We first perform estimates and discuss the main physics, and later outline the techniques that allow to perform precise computations.

Martin Tamm

In this paper I suggest a possible explanation for the asymmetry of time. In the case that I study, the dynamical laws and the boundary conditions are symmetric, but the behavior of time is not. The underlying mechanism is statistical and closely related to the idea of multiple histories in quantum mechanics, but otherwise rather independent of the particula

Geoffrey L. Greene, Vladimir Gudkov

In recent years, an energetic experimental program has set quite stringent limits on a possible "non - 1/r^2" dependence on gravity at short length scales. This effort has been largely driven by the predictions of theories based on compactification of extra spatial dimensions. It is characteristic of many such theories that the strength and length scales of

V. I. Man'ko, O. V. Pilyavets, V. G. Zborovskii

The probability representation of states in standard quantum mechanics where the quantum states are associated with fair probability distributions (instead of wave function or density matrix) is shortly commented and bibliography related to the probability representation is given.

Markus Boettcher

Blazars are the most violent steady/recurrent sources of high-energy gamma-ray emission in the known Universe. They are prominent emitters of electromagnetic radiation throughout the entire electromagnetic spectrum. The observable radiation most likely originates in a relativistic jet oriented at a small angle with respect to the line of sight. This review s

Cuihua Du, Jun Ma, Zhenyu Wu, Xu Zhou

We present an analysis of the photometric parallaxes of stars in 21 BATC fields carried out with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope in 15 intermediate-band filters from 3000 to 10000 {\AA}. In this study, we have adopted a three-component (thin disk, thick disk and halo) model to analyze star counts information. By calc

S. Stepanyan, S. Boyarinov, H. Egiyan, L. Guo

In this report, we present the energy calibration of the Hall B bremsstrahlung tagging system at the Thomas Jefferson National Accelerator Facility. The calibration was performed using a magnetic pair spectrometer. The tagged photon energy spectrum was measured in coincidence with $e^+e^-$ pairs as a function of the pair spectrometer magnetic field. Taking a

J. Hong, J. E. Grindlay, N. Chammas, A. Copete

We describe the detector development for a balloon-borne wide-field hard X-ray (20 - 600 keV) telescope, ProtoEXIST. ProtoEXIST is a pathfinder for both technology and science of the proposed implementation of the Black Hole Finder Probe, Energetic X-ray Imaging Survey telescope (EXIST). The principal technology challenge is the development of large area, cl

Peter Matus, Henri Alloul, Gyorgy Kriza, Veronique Brouet

We have investigated sodium containing fullerene superconductors Na2AC60, A = Cs, Rb, and K, by Na-23 nuclear magnetic resonance (NMR) spectroscopy at 7.5 T in the temperature range of 10 to 400 K. Despite the structural differences from the Rb3C60 class of fullerene superconductors, in these compounds the NMR line of the tetrahedrally coordinated alkali nuc

Dragan Huterer, Eric V. Linder

The acceleration of the cosmic expansion may be due to a new component of physical energy density or a modification of physics itself. Mapping the expansion of cosmic scales and the growth of large scale structure in tandem can provide insights to distinguish between the two origins. Using Minimal Modified Gravity (MMG) - a single parameter gravitational gro

Javier Pérez-Moreno, Yuxia Zhao, Koen Clays, Mark G. Kuzyk

We report on a series of chromophores that have been synthesized with a modulated conjugation path between donor and acceptor. Hyper-Rayleigh scattering measurements of the best molecule show an enhanced intrinsic hyperpolarizability that breaches the apparent limit of all previously studied molecules.

A. Siddiki

In this work we implement the self-consistent Thomas-Fermi approach and a local conductivity model to an electron-electron bilayer system. The presence of an incompressible strip, originating from screening calculations at the top (or bottom) layer is considered as a source of an external potential fluctuation to the bottom (or top) layer. This essentially y

Branko J. Malesevic

In this article $\lambda$-method of Mitrinovic-Vasic \cite{MitrinovicVasic70} is applied to improve the upper bound for the arcsin function of L. Zhu \cite{Zhu05} for inequalities of Shafer-Fink's type.

W. Schäfer

The inclusive production of high-p_\perp particles (pions) in the beam fragmentation regions of high-energy hadronic collisions is driven by the breakup of valence constituents of the beam hadrons into their two-body Fock-state components,and their subsequent fragmentation. We briefly discuss an approach, that allows the consistent inclusion of intrinsic and

M. F. Higareda, H. Hernández-Saldaña, R. A. Méndez-Sánchez

We show that the nearest neighbour distribution of distances between basis pairs of some intron-less and intron-containing coding regions are the same when a procedure, called {\em unfolding}, is applied. Such a procedure consists in separating the secular variations from the oscillatory terms. The form of the distribution obtained is quite similar to that o

F. Yusef-Zadeh, M. Muno, M. Wardle, D. C. Lis

(Abridged) The inner couple hundred pcs of our Galaxy is characterized by significant amount of synchrotron-emitting gas, which appears to co-exist with a large reservoir of molecular gas. The spatial correlation between fluorescent Fe K-alpha line emission at 6.4 keV and molecular line emission from Galactic center molecular clouds has been explained as ref

A. A. Djupvik, Ph. Andre, S. Bontemps, F. Motte

Aims. The aim of this paper is to characterise the star formation activity in the poorly studied embedded cluster Serpens/G3-G6, located ~ 45' (3 pc) to the south of the Serpens Cloud Core, and to determine the luminosity and mass functions of its population of Young Stellar Objects (YSOs). Methods. Multi-wavelength broadband photometry was obtained to sampl

K. Tsigutkin, J. E. Stalnaker, D. Budker, S. J. Freedman

We discuss experiments aimed at measurements of atomic parity nonconservation (PNC) effects in the 1S0-3D1 transition (408 nm) in atomic Ytterbium (Z=70). According to theoretical predictions, the PNC-induced E1 amplitude of this transition is ~100 times larger than the analogous amplitude in Cs. Such an experiment will determine differences in PNC effects b

Michael A. van Opstall, Razvan Veliche

We find a sharp bound for the order of the automorphism group of a stable curve of genus $g$ with $3g-3$ nodes, and a sharp bound for the order of the automorphism group of such a curve with all smooth components. Combined with the results of our article math.CO/0608645 we find that graph theoretically, the cubic graph with a given number of vertices and mos

Reese Scott

Considering the equation $$a^x+b^y = c^z,$$ Le gives an upper bound on the number of solutions $(x,y,z)$, and a bound on $z$. Here we give slight improvements to these results, also removing the restriction that $a$, $b$, $c$ be squarefree.

Paul D. Feldman, S. Alan Stern, Andrew J. Steffl, Joel Wm. Parker

We report on spectroscopic observations of periodic comet 9P/Tempel 1 by the Alice ultraviolet spectrograph on the Rosetta spacecraft in conjunction with NASA's Deep Impact mission. Our objectives were to measure an increase in atomic and molecular emissions produced by the excavation of volatile sub-surface material. We unambiguously detected atomic oxygen

S. Graser, T. Dahm

We study the influence of multiple bands on the properties of Josephson junctions. In particular we focus on the two gap superconductor magnesium diboride. We present a formalism to describe tunneling at a point contact between two MgB2 electrodes generalizing the transfer-matrix approach to multiple bands. A simple model is presented to determine the effect

M. Orellana, G. E. Romero

LS I+61 303 has been detected by the Cherenkov telescope MAGIC at very high energies, presenting a variable flux along the orbital motion with a maximum clearly separated from the periastron passage. In the light of the new observational constraints, we revisit the discussion of the production of high-energy gamma rays from particle interactions in the inner

Nick S. Norberg, Gustavo M. Dalpian, James R. Chelikowsky, Daniel R. Gamelin

Spectroscopic data demonstrate that impurity D/A levels in doped semiconductor nanostructures are energetically pinned, resulting in variations in D/A binding energies with increasing quantum confinement. Using magnetic circular dichroism spectroscopy, the donor binding energies of Co2+ ions in colloidal ZnSe quantum dots have been measured as a function of

Peter Constantin, Gautam Iyer

We discuss stochastic representations of advection diffusion equations with variable diffusivity, stochastic integrals of motion and generalized relative entropies.

Florian Gmeiner

In this article, which is based on the first part of my PhD thesis, I review the statistics of the open string sector in T^6/(Z_2xZ_2) orientifold compactifications of the type IIA string. After an introduction to the orientifold setup, I discuss the two different techniques that have been developed to analyse the gauge sector statistics, using either a sadd

Gianfranco Bertone

We review the status of indirect Dark Matter searches, focusing in particular on the connection with gamma-ray Astrophysics, and on the prospects for detection with the upcoming space telescope GLAST and Air Cherenkov Telescopes such as CANGAROO, HESS, MAGIC and VERITAS. After a brief introduction where we review the fundamental motivations for indirect sear

Randy Lewis

Extraction of the nucleon's strange form factors from experimental data requires a quantitative understanding of the unavoidable contamination from isospin violation. A number of authors have addressed this issue during the past decade, and their work is reviewed here. The predictions from early models are largely consistent with recent results that rely as

Reese Scott

We give a shorter simpler proof of a result of Szalay on the equation $2^a + 2^b + 1 = z^2$. We give an elementary proof of a result of Luca on the equation of the title for prime $p > 2$. The elementary treatment is made possible by a lemma which is also useful for other Diophantine equations.

David Cimasoni, Nicolai Reshetikhin

Partition functions for dimers on closed oriented surfaces are known to be alternating sums of Pfaffians of Kasteleyn matrices. In this paper, we obtain the formula for the coefficients in terms of discrete spin structures.

David M. D. Smith, Chiu Fan Lee, Neil F. Johnson

We introduce a simple one-parameter network growth algorithm which is able to reproduce a wide variety of realistic network structures but without having to invoke any global information about node degrees such as preferential-attachment probabilities. Scale-free networks arise at the transition point between quasi-random and quasi-ordered networks. We provi

J. Lohkamp

We derive the Riemannian Positive Mass theorem in arbitrary dimensions, without any topological constraints. The main new tools are skin structures and surgeries on minimal hypersurfaces.

Roberto B. Diener, Tin-Lun Ho

We show that the quantum evolution of a spin-1 Bose gas with nearly all bosons initially in the $F_z = 0$ state has a "quantum carpet" {\em spin-time} structure with self-similar properties. The system continuously evolves into "multi-peaked" Schr\"odinger cat like states, returning occasionally to coherent structures, which leads to large number fluctuation

Christopher Smith

The theoretical status of the rare K --> pi nu nu, KL --> pi0 l+ l- and KL --> mu+ mu- decays in the Standard Model is reviewed. Their sensitivity to New Physics and their discriminating power is also illustrated.

D. Gepner, Shesansu Pal

We study intersection of $N_c$ color D4 branes with $N_f$ Dp-branes and anti-Dp branes in the strong coupling limit in the probe approximation. The resulting model has $U(N_f)\times U(N_f)$ global symmetry. We see an $n$ dimensional theory for $n$ overlapping directions between color and flavor branes. At zero temperature we do see the breakdown of chiral sy

Wang-Kong Tse, S. Das Sarma

Employing diagrammatic perturbation theory, we calculate the (charge) Coulomb drag resistivity $\rho_D$ and spin Coulomb drag resistivity $\rho_{\uparrow\downarrow}$ in the presence of Rashba spin-orbit coupling. Analytical expressions for $\rho_D$ and $\rho_{\uparrow\downarrow}$ are derived, and it is found that spin-orbit interaction produces a small enhan

Friedrich Hegenbarth, Dušan Repovš

It is well-known that an n-dimensional Poincar\'{e} complex $X^n$, $n \ge 5$, has the homotopy type of a compact topological $n$-manifold if the total surgery obstruction $s(X^n)$ vanishes. The present paper discusses recent attempts to prove analogous result in dimension 4. We begin by reviewing the necessary algebraic and controlled surgery theory. Next, w

A. K. Pandey, S. Sharma, K. Ogura

We present colour-magnitude diagrams of open clusters, located in the range $112^\circ < l < 252^\circ$, manifesting stellar populations in the background of clusters. Some of the populations are found to be located beyond the Perseus arm and may be the part of Norma-Cygnus (outer) arm. The outer arm seems to be continued from $l\sim120^\circ$ to $l\sim235^\

John W. Barrett

A formulation of the non-commutative geometry for the standard model of particle physics with a Lorentzian signature metric is presented. The elimination of the fermion doubling in the Lorentzian case is achieved by a modification of Connes' internal space geometry so that it has signature 6 (mod 8) rather than 0. The fermionic part of the Connes-Chamseddine

Efim A. Brener, V. I. Marchenko, R. Spatschek

We consider a sharp interface kinetic model of phase transitions accompanied by elastic strain, together with its phase-field realization. Quantitative results for the steady-state growth of a new phase in a strip geometry are obtained and different pattern formation processes in this system are investigated.

S. Dubnicka, A. Z. Dubnickova

Special eight-resonance unitary and analytic model of nucleon electromagnetic structure is used to analyze, first the classical proton form factor data obtained by the Rosenbluth technique and then also the contradicting JLab proton polarization data on the ratio $\mu_p G_{Ep}(Q^2)/G_{Mp}(Q^2)$ with the aim to investigate a manifestation of the latter on the

Abhishek Parakh

We investigate the mathematics behind 1500 year old root extraction methods presented by Aryabhata in his famous mathematical treatise "Aryabhatiya". Also, we look at their computational complexity.

B. Hippolyte

Strange quark and hadron production will be studied at the Large Hadron Collider (LHC) energies in order to explore the properties of both pp and heavy-ion collisions. The ALICE experiment will be specifically efficient in the strange sector with the identification of baryons and mesons over a wide range of transverse momentum. Dedicated measurements are pro

A. Bik, L. Kaper, M. M. Hanson, L. B. F. M. Waters

We have obtained high resolution (R = 10,000) K-band spectra of candidate young massive stars deeply embedded in high-mass star-forming regions. These objects were selected from a near-infrared survey of 44 regions of high-mass star-formation (Kaper et al, 2006). In these clusters, 38 OB stars are identified whose K-band spectra are dominated by photospheric

Daniel Bonamy, Silke Prades, Cindy Rountree, Laurent Ponson

We report here atomic force microscopy experiments designed to uncover the nature of failure mechanisms occuring within the process zone at the tip of a crack propagating into a silica glass specimen under stress corrosion. The crack propagates through the growth and coalescence of nanoscale damage spots. This cavitation process is shown to be the key mechan

B. -W. Schulze, A. Volpato

The task to construct parametrices of elliptic differential operators on a manifold with edges requires a calculus of operators with a two-component principal symbolic hierarchy, consisting of (edge-degenerate) interior and (operator-valued) edge symbols. This so-called edge-algebra can be interpreted as a generalisation of the (pseudo-differential) algebra

S. M. Shapiro, P. Vorderwisch, K. Habicht, K. Hrdil

An inelastic neutron scattering study of the lattice dynamics of the martensite phase of the ferromagnetic shape memory alloy, Ni2MnGa, reveals the presence of well-defined phasons associated with the charge density wave (CDW) resulting from Fermi surface (FS) nesting. The velocity and the temperature dependence of the phason are measured as well as the anom

Jacek Szklarski, Günther Rüdiger

The magnetorotational instability (MRI) in cylindrical Taylor-Couette flow with external helical magnetic field is simulated for infinite and finite aspect ratios. We solve the MHD equations in their small Prandtl number limit and confirm with time-dependent nonlinear simulations that the additional toroidal component of the magnetic field reduces the critic

F. Fontani, P. Caselli, A. Crapsi, R. Cesaroni

We have measured the deuterium fractionation (through the column density ratio N(N2D+)/N(N2H+)) and the CO depletion factor (ratio between expected and observed CO abundance) in a sample of 10 high-mass protostellar candidates, in order to understand whether the earliest evolutionary stages of high-mass stars have chemical characteristics similar to those of

Susan J. Sierra

Given Z-graded rings A and B, we study when the categories gr-A and gr-B are equivalent. We relate the Morita-type results of Ahn-Marki and del Rio to the twisting systems introduced by Zhang. Using Z-algebras, we obtain a simple proof of Zhang's main result. This makes the definition of a Zhang twist extremely natural and extends Zhang's results.

A. Alexandrov, A. Mironov, A. Morozov

Various branches of matrix model partition function can be represented as intertwined products of universal elementary constituents: Gaussian partition functions Z_G and Kontsevich tau-functions Z_K. In physical terms, this decomposition is the matrix-model version of multi-instanton and multi-meron configurations in Yang-Mills theories. Technically, decompo

Robert Seiringer

A lower bound is derived on the free energy (per unit volume) of a homogeneous Bose gas at density $\rho$ and temperature $T$. In the dilute regime, i.e., when $a^3\rho \ll 1$, where $a$ denotes the scattering length of the pair-interaction potential, our bound differs to leading order from the expression for non-interacting particles by the term $4\pi a (2\

W. Zhang, H. -S. Chiang, M. A. Zudov, L. N. Pfeiffer

We report on nonequilibrium transport measurements in a high-mobility two-dimensional electron system subject to weak magnetic field and dc excitation. Detailed study of dc-induced magneto-oscillations, first observed by Yang {\em et al}., reveals a resonant condition that is qualitatively different from that reported earlier. In addition, we observe dramati

P. T. P. Hutauruk, A. Sulaksono, T. Mart

We have studied the effects of the nucleon weak magnetism and the neutrino electromagnetic properties on the neutrino and antineutrino mean free paths for all types of neutrinos. In the calculation, we consider matters with and without neutrino trapping as the target. We have found that the difference between the two mean free paths depends not only on the n

Aristide Tsemo

In this paper, we study cryptography from a geometrical viewpoint. Let N be a network, we endow N with a natural Grothendieck topology. We use geometric representations of cohomological classes to define encryptions protocols. Link to link encryption is related to the notion of torsors. We use the notion of connective structure defined on a gerbe to define p

Ioannis Contopoulos Demosthenes Kazanas Dimitris M. Christodoulou

We reinvestigate the generation and accumulation of magnetic flux in optically thin accretion flows around active gravitating objects. The source of the magnetic field is the azimuthal electric current associated with the Poynting-Robertson drag on the electrons of the accreting plasma. This current generates magnetic field loops which open up because of the

Branko J. Malesevic

In this article we consider a method for proving a class of analytical inequalities via minimax rational approximations. All numerical calculations in this paper are given by Maple computer program.

A. J. Daley, A. Kantian, H. P. Büchler, P. Zoller

We review the basic physics of repulsively bound atom pairs in an optical lattice, which were recently observed in the laboratory, including the theory and the experimental implementation. We also briefly discuss related many-body numerical simulations, in which time-dependent Density Matrix Renormalisation Group (DMRG) methods are used to model the many-bod

Alexander D. Popov, Martin Wolf

We describe an infinite-dimensional algebra of hidden symmetries of N=4 supersymmetric Yang-Mills (SYM) theory. Our derivation is based on a generalization of the supertwistor correspondence. Using the latter, we construct an infinite sequence of flows on the solution space of the N=4 SYM equations. The dependence of the SYM fields on the parameters along th

Soumitra Nandi, Jyoti Prasad Saha

We discuss the implications of the recent measurement of the $B_s-\bar{B_s}$ oscillation frequency $\Delta M_s$ on the parameter space of R-parity violating supersymmetry. For completeness, we also discuss the bounds coming from leptonic, semileptonic, and nonleptonic B decay modes, and point out some possibly interesting channels at LHC.

M. V. Katkov, Y. V. Pershin, C. Piermarocchi

We consider a semiconductor polymer chain coupled to a single electromagnetic mode in a cavity. The excitations of the chain have a mixed exciton-photon character and are described as polaritons. Polaritons are coupled to the lattice by the deformation potential interaction and can propagate in the chain. We find that the presence of optical excitation in th

Håkan Samuelsson

Let $f_1$, $f_2$, and $f_3$ be holomorphic functions on a complex manifold and assume that the common zero set of the $f_j$ has maximal codimension, i.e., that it is a complete intersection. We prove that the iterated Mellin transform of the residue integral has an analytic continuation to a neighborhood of the origin in $\mathbb{C}^3$. We prove also that th

J. H. Croston, M. Arnaud, E. Pointecouteau, G. W. Pratt

We have developed a regularisation procedure for the direct deprojection and PSF-deconvolution of X-ray surface brightness profiles of clusters of galaxies. This procedure allows us to obtain accurate density profiles in a straightforward manner from X-ray observations (in particular data from XMM-Newton, where the PSF correction is important), while retaini

S. Costamagna, C. J. Gazza, M. E. Torio, J. A. Riera

An Anderson impurity in a Hubbard model on chains with finite length is studied using the density-matrix renormalization group (DMRG) technique. In the first place, we analyzed how the reduction of electron density from half-filling to quarter-filling affects the Kondo resonance in the limit of Hubbard repulsion U=0. In general, a weak dependence with the el

Brian Rider, Balint Virag

For the plane, sphere, and hyperbolic plane we consider the canonical invariant determinantal point processes with intensity rho dnu, where nu is the corresponding invariant measure. We show that as rho converges to infinity, after centering, these processes converge to invariant H1 noise. More precisely, for all functions f in the interesection of H1(nu) an