March 2006 arXiv papers — page 14

B. G. Sidharth

Einstein's Special Theory of Relativity was proposed a little over a hundred years back. It remained a bedrock of twentieth century physics right up to Quantum Field Theory. However, the failure over several decades to provide a unified description of Electromagnetism and Gravitation or alternatively, Quantum Theory and General Relativity has finally lea

Z. Huang, G. Stupakov, S. Reiche

Various methods have been proposed to condition an electron beam in order to reduce its emittance effect and to improve the short-wavelength free electron laser (FEL) performance. In this paper, we show that beam conditioning does not result in a complete elimination of the emittance effect in an alternating-gradient focusing FEL undulator. Using a one-dimen

S. V. Kukhlevsky

Subwavelength aperture arrays in thin metal films enable enhanced transmission of light and matter waves [for example, see T.W. Ebbesen et al., Nature (London) 391, 667 (1998) and E. Moreno et al., Phys. Rev. Lett. 95, 170406 (2005)]. The phenomenon relies on resonant excitation of the surface electron or matter waves. We show another mechanism that provides

M. Grasso, S. Yoshida, N. Sandulescu, N. Van Giai

Giant neutron halos in medium-heavy nuclei are studied in the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions. The appearance of such structures depends sensitively on the effective interaction adopted. This is illustrated by comparing the predictions of SLy4 and SkI4 in the Ca and Zr isotopic chains. The former force gives n

N. Minkov, P. Yotov, S. Drenska, W. Scheid

A collective Hamiltonian for the rotation-vibration motion of nuclei is considered, in which the axial quadrupole and octupole degrees of freedom are coupled through the centrifugal interaction. The potential of the system depends on the two deformation variables $β_2$ and $β_3$. The system is considered to oscillate between positive and negative $β_3$-value

G. Erkol, M. Oka, Th. A. Rijken, R. G. E. Timmermans

The external-field QCD Sum Rules method is used to evaluate the coupling constants of the light-isoscalar scalar meson (``σ'' or ε) to the Λ, Σ, and Ξbaryons. It is shown that these coupling constants as calculated from QCD Sum Rules are consistent with SU(3)-flavor relations, which leads to a determination of the F/(F+D) ratio of the scalar octet as

N. Minkov, P. Yotov, S. Drenska, W. Scheid

We propose a collective model formalism which describes the strong parity shift observed in low-lying spectra of nuclei with octupole deformations together with the fine rotational band structure developed at higher angular momenta. The parity effect is obtained by the Schroedinger equation for oscillations of the reflection asymmetric (octupole) shape betwe

G. Erkol, Th. A. Rijken, R. G. E. Timmermans

The external-field QCD Sum Rules method is used to evaluate the coupling constant of the light isoscalar-scalar meson (``$σ$'' or ε) to the nucleon. The contributions that come from the excited nucleon states and the response of the continuum threshold to the external field are calculated. The obtained value of the coupling constant is compatible wit

Masayuki Matsuzaki

We study effects of the medium polarization on superfluidity in symmetric nuclear matter in a relativistic formalism. An effect of the liquid-gas instability is emphasized. We examine two types of decomposition of the nucleon propagator; the standard Feynman-density and the particle-hole-antiparticle ones. In both cases, the medium polarization effect is det

J. Smyrski, H. -H. Adam, A. Budzanowski, E. Czerwinski

We present preliminary results from dp --> 3He X (X=pi0,eta) measurements near the eta production threshold. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target. The 3He ejectiles were registered with the COSY-11 detection setup. The ongoing data analysis should deliver high precision data for the dp -->

J. Gomez-Gardenes, B. A. Malomed, L. M. Floria, A. R. Bishop

We consider a lattice equation (Salerno model) combining onsite self-focusing and intersite self-defocusing cubic terms, which may describe a Bose-Einstein condensate of dipolar atoms trapped in a strong periodic potential. In the continuum approximation, the model gives rise to solitons in a finite band of frequencies, with sechlike solitons near one edge,

Louis Gostiaux, Thierry Dauxois, Henri Didelle, Joel Sommeria

Internal waves propagate obliquely through a stratified fluid with an angle that is fixed with respect to gravity. Upon reflection on a sloping bed, striking phenomena are expected to occur close to the slope. We present here laboratory observations at moderately large Reynolds number. A particle image velocimetry (PIV) technique is used to provide time reso

Zhou Gang, I. M. Sigal

In this paper we announce the result of asymptotic dynamics of solitons of nonlinear Schrodinger equations with external potentials. To each local minima of the potential there is a soliton centered around it. Under some conditions on the nonlinearity, the potential and the datum, we prove that the solution can be decomposed into two parts: the soliton and t

Boujemaa Agrebaoui, Nizar Ben Fraj, Salem Omri

We classify nontrivial deformations of the standard embedding of the Lie superalgebra K(1) of contact vector fields on the (1,1)-dimensional supercircle into the Lie superalgebra of superpseudodifferential operators on the supercircle. This approach leads to the deformations of the central charge induced on K(1) by the canonical central extension of $SΨDO$.

Boujemaa Agrebaoui, Nizar Ben Fraj, Salem Omri

We investigate the first cohomology space associated with the embedding of the Lie superalgebra $\cK(2)$ of contact vector fields on the (1,2)-dimensional supercircle $S^{1\mid 2}$ in the Lie superalgebra $\cSΨ\cD \cO(S^{1\mid 2})$ of superpseudodifferential operators with smooth coefficients. Following Ovsienko and Roger, we show that this space is ten-dime

Vadim Kostrykin, Ivan Veselic

The present paper is devoted to the study of spectral properties of random Schroedinger operators. Using a finite section method for Toeplitz matrices, we prove a Wegner estimate for some alloy type models where the single site potential is allowed to change sign. The results apply to the corresponding discrete model, too. In certain disorder regimes we are

Tobias Mühlenbruch

This is basically a summary of [Mu]. The focus of the paper is the explicit computation of Hecke operators for period functions. In particular we compute the matrix representations of the 2nd Hecke operator on period functions for the full modular group $SL(2,Z)$ and the congruence subgroup $Γ_0(2)$. [Mu] Tobias Mühlenbruch. Hecke operators on period functio

Maurizio Martino

We investigate the Poisson geometry of the Marsden-Weinstein reductions of the moment map associated to the cotangent bundle of the space of representations of a quiver. We show that the stratification by representation type equals the stratification by symplectic leaves. The deformed symplectic quotient singularities - spectra of centres of symplectic refle

Mathew D. Penrose, Andrew R. Wade

In the on-line nearest-neighbour graph (ONG), each point after the first in a sequence of points in R^d is joined by an edge to its nearest-neighbour amongst those points that precede it in the sequence. We study the large-sample asymptotic behaviour of the total power-weighted length of the ONG on uniform random points in (0,1)^d. In particular, for d=1 and

Vdovin Evgenii

In the paper we obtain the existence criterion of a Carter subgroup in a finite group in terms of its normal series. An example showing that the criterion cannot be reformulated in terms of composition factors is given.

Raf Bocklandt

In this paper we prove that Graded Calabi Yau Algebras of dimension 3 are isomorphic to path algebras of quivers with relations derived from a superpotential. We show that for a given quiver $Q$ and a degree $d$, the set of good superpotentials of degree $d$, i.e. those that give rise to Calabi Yau algebras is either empty or almost everything (in the measur

Michael Stoll

In this paper, we study bounds for the number of rational points on twists C' of a fixed curve C over a number field K, under the condition that the group of K-rational points on the Jacobian J' of C' has rank smaller than the genus of C'. The main result is that with some explicitly given finitely many possible exceptions, we have a bound of

Martine Girard, David R. Kohel

We describe the invariants of plane quartic curves -- nonhyperelliptic genus 3 curves in their canonical model -- as determined by Dixmier and Ohno, with application to the classification of curves with given structure. In particular, we determine modular equations for the strata in the moduli space $\Me_3$ of plane quartics which have at least seven hyperfl

Alice C. Niemeyer, Cheryl E. Praeger

A general explicit upper bound is obtained for the proportion $P(n,m)$ of elements of order dividing $m$, where $n-1 \le m \le cn$ for some constant $c$, in the finite symmetric group $S_n$. This is used to find lower bounds for the conditional probabilities that an element of $S_n$ or $A_n$ contains an $r$-cycle, given that it satisfies an equation of the f

Darren Creutz, Cesar E. Silva

We prove that mixing on rank-one transformations is equivalent to the spacer sequence being slice-ergodic. Slice-ergodicity, introduced in this paper, generalizes the notion of ergodic sequence to the uniform convergence of ergodic averages (as in the mean ergodic theorem) over subsequences of partial sums. We show that polynomial staircase transformations s

David E Speyer

Let G(d,n) denote the Grassmannian of d-planes in C^n and let T be the torus (C^*)^n/diag(C^*) which acts on G(d,n). Let x be a point of G(d,n) and let \bar{Tx} be the closure of the T-orbit through x. Then the class of the structure sheaf of \bar{Tx} in the K-theory of G(d,n) depends only on which Plücker coordinates of x are nonzero -- combinatorial data k

E. Kirr, A. Zarnescu

We consider the cubic nonlinear Schrödinger equation in two space dimensions with an attractive potential. We study the asymptotic stability of the nonlinear bound states, i.e. periodic in time localized in space solutions. Our result shows that all solutions with small, localized in space initial data, converge to the set of bound states. Therefore, the cen

Katsunori Kawamura

We introduce representations of the Cuntz algebra $\con$ which are parameterized by sequences in the set of unit vectors in ${\bf C}^{N}$. These representations are natural generalizations of permutative representations by Bratteli-Jorgensen and Davidson-Pitts. We show their existence, irreducibility, equivalence, uniqueness of irreducible decomposition and

Vesselin Drensky, Liliya Sadikova

Over a field of characteristic 0, the algebra of invariants of several $n\times n$ matrices under simultaneous conjugation by $GL_n$ is generated by traces of products of generic matrices. In this paper we have found, in terms of representation theory of $GL_2$, a minimal set of generators of the algebra of invariants of two $4\times 4$ matrices. The proof i

A. V. Jayanthan, Tony J. Puthenpurakal, J. K. Verma

Two formulas for the multiplicity of the fiber cone $F(I)=\oplus_{n=0}^{\infty} I^n/\m I^n$ of an $\m$-primary ideal of a $d$-dimensional Cohen-Macaulay local ring $(R,\m)$ are derived in terms of the mixed multiplicity $e_{d-1}(\m | I),$ the multiplicity $e(I)$ and superficial elements. As a consequence, the Cohen-Macaulay property of $F(I)$ when $I$ has mi

Olivera Miskovic, Ricardo Troncoso, Jorge Zanelli

Some dynamical aspects of five-dimensional supergravity as a Chern-Simons theory for the SU(2,2|N) group, are analyzed. The gravitational sector is described by the Einstein-Hilbert action with negative cosmological constant and a Gauss-Bonnet term with a fixed coupling. The interaction between matter and gravity is characterized by intricate couplings which

Seok Kim, Ki-Myeong Lee, Ho-Ung Yee

To a domain wall or string object, Noether charge and topological spatial objects can be attracted, forming a composite BPS (Bogomolny-Prasad-Sommerfield) object. We consider two field theories and derive a new BPS bound on composite linear solitons involving multiple charges. Among the BPS objects `supertubes' appear when the wall or string tension is c

Zoltán Kovács, László Á. Gergely

Geometric variables naturally occurring in a time-like foliation of brane-worlds are introduced. These consist of the induced metric and two sets of lapse functions and shift vectors, supplemented by two sets of tensorial, vectorial and scalar variables arising as projections of the two extrinsic curvatures. A subset of these variables turn out to be dynamic

Alexander Westphal

Higher-order alpha'-corrections are a generic feature of type IIB string compactifications. In KKLT-like models of moduli stabilization they provide a mechanism of breaking the no-scale structure of the volume modulus. We present a model of inflation driven by the volume modulus of flux compactifications of the type IIB superstring. Using the effects of

J. A. Aguilar-Saavedra

New quark singlets T can be produced in pairs at LHC through standard QCD interactions, with a large cross section for masses of several hundreds of GeV. Their charged current decays T Tbar T -> W+ b W- bbar, with semileptonic decay of the W pair, give a final state l nu bb jj$, as in top pair production. The mixed decay modes T Tbar -> W+ b H tbar, H t W- b

Howard Baer, Azar Mustafayev, Eun-Kyung Park, Stefano Profumo

In gravity-mediated SUSY breaking models with non-universal gaugino masses, lowering the SU(3) gaugino mass |M_3| leads to a reduction in the squark and gluino masses. Lower third generation squark masses, in turn, diminish the effect of a large top quark Yukawa coupling in the running of the higgs mass parameter m_{H_u}^2, leading to a reduction in the magn

M. D. Scadron, R. Delbourgo, G. Rupp

Constituent quark masses can be determined quite well from experimental data in several ways and one can obtain fairly accurate values for all six $m_q$. The strong quark-meson coupling $g=2π/\sqrt{3}$ arises from the quark-level linear $σ$ model, whereas $e$ and $\sinθ_w$ arise from weak interactions when the heavy $M_W$ and $M_Z$ are regarded as resonances

Klaus Werner

We have demonstrated recently that RHIC heavy ion data concerning particle production at small and intermediate transverse momenta become very transparent, if one realizes that there are two sources of particles production: the corona -- due to the interactions of the peripheral nucleons of either nucleus, and the core -- representing the high density centra

F. W. Bopp, Yu. M. Shabelski

The process of baryon number transfer due to string junction propagation in rapidity space is considered. It leads to a significant effect in the net baryon production in pA collisions at mid-rapidities and an even more significant effect in the forward hemisphere for the cases of πA interactions. The results of numerical calculations in the framework of the

E. Iltan

We predict the branching ratios of Z-> e^{\pm} μ^{\pm}, Z-> e^{\pm} τ^{\pm} and Z-> μ^{\pm} τ^{\pm} decays in the framework of the 2HDM with the inclusion of one and two extra dimensions, by considering that the new Higgs doublet is localized in the extra dimension with a Gaussian profile. We observe that their BRs are at the order of the magnitude of $10^{-

V. G. Baryshevsky

The equations for spin evolution of a particle in a storage ring are obtained considering contributions from the tensor electric and magnetic polarizabilities of the particle along with the contributions from spin rotation and birefringence effect in polarized matter of an internal target. % Study of the spin rotation and birefringence effects for a particle

N. Nimai Singh, Monisa Rajkhowa, Abhijit Borah

An attempt is made to explore the possibility for deviations of solar mixing angle ($θ_{12}$) from tri-bimaximal mixings, without sacrificing the predictions of maximal atmospheric mixing angle ($θ_{23}=π/4$) and zero reactor angle ($θ_{13}=0$). We find that the above conjecture can be automatically realised in the inverted hierarchical neutrino mass model h

Zvi Bern, N. E. J. Bjerrum-Bohr, David C. Dunbar, Harald Ita

We describe the recursive Approach to One-loop QCD Matrix Elements.

M. A. Braun, C. Pajares

In AA collisions fusion and percolation of colour strings is studied at fixed rapidity $y$. Distribution of strings in rapidity is obtained from the observed rapidity spectra in pp collisions. For $y$-dependence of multiplicities in Au-Au collisions good agreement is obtained with the existing experimental data. Predictions for LHC energies coincide with the

Zhao Zhang, Wei-qin Zhao

We compute the dimension-2 gluon pair condensate $g^2<{AA}>$ and the dimension-4 mixed quark-gluon condensate $<\bar{q}gA\cdotγ{q}>$ in Landau gauge within the framework of global color model. The result for the dynamical gluon mass is within the range given by other independent determinations. The obtained mixed Landau gauge condensate $<\bar{q}gA\cdotγ{q}>

S. I. Kruglov

Dynamical and non-dynamical components of the 20-component wave function are separated in the generalized Dirac equation of the first order, describing fermions with spin 1/2 and two mass states. After the exclusion of the non-dynamical components, we obtain the Hamiltonian Form of equations. Minimal and non-minimal electromagnetic interactions of particles

Xiaorong Wang

PHENIX results for open charm production from semi-lepton decay in p+p, d+Au and Au+Au collisions in a wide rapidity ranges at $\sqrt(s)= 200$ GeV are presented. Keywords: Relativistic Heavy-ion Collision, Open Charm production, Nuclear Medium Effect PACS: 25.75.-q, 25.75 Dw, 13.20.Gd

NA50 Collaboration

The NA50 Collaboration has measured heavy-quarkonium production in p-A collisions at 450 GeV incident energy (sqrt(s) = 29.1 GeV). We report here results on the production of the Upsilon states and of high-mass Drell-Yan muon pairs (m > 6 GeV). The cross-section at midrapidity and the A-dependence of the measured yields are determined and compared with the r

B Collaboration

A measurement of the polarization of Lambda and Anti-Lambda baryons produced in pC and pW collisions at sqrt(s)=41.6 GeV has been performed with the HERA-B spectrometer. The measurements cover the kinematic range of 0.6 GeV/c < p_T<1.2 GeV/c in transverse momentum and -0.15<x_F<0.01 in Feynman-x. The polarization results from the two different targets agree

A. N. St. J. Farley, P. D. D&#39;Eath

In earlier Letters, we adopted a complex approach to quantum processes in the formation and evaporation of black holes. Taking Feynman&#39;s $+iε$ prescription, rather than than one of the more usual approaches, we calculated the quantum amplitude (not just the probability density) for final weak-field configurations following gravitational collapse to a bla

Yan-Xiu Zheng, Yu T. Su

Conventional turbo codes (CTCs) usually employ a block-oriented interleaving so that each block is separately encoded and decoded. As interleaving and de-interleaving are performed within a block, the message-passing process associated with an iterative decoder is limited to proceed within the corresponding range. This paper presents a new turbo coding schem

Maurice Margenstern

In this paper, we prove that the general problem of tiling the hyperbolic plane with à la Wang tiles is undecidable.

Himanshu Thapliyal, M. B Srinivas

In recent years, reversible logic has emerged as a promising computing paradigm having its applications in low power computing, quantum computing, nanotechnology, optical computing and DNA computing. The classical set of gates such as AND, OR, and EXOR are not reversible. Recently, it has been shown how to encode information in DNA and use DNA amplification

Himanshu Thapliyal, M. B Srinivas

In the recent years, reversible logic has emerged as a promising technology having its applications in low power CMOS, quantum computing, nanotechnology, and optical computing. The classical set of gates such as AND, OR, and EXOR are not reversible. This paper proposes a new 4 * 4 reversible gate called TSG gate. The proposed gate is used to design efficient

Teng Yang, Shinya Okano, Savas Berber, David Tomanek

We investigate the equilibrium geometry and electronic structure of Mo$_{12}$S$_{9}$I$_{9}$ nanowires using ab initio Density Functional calculations. The skeleton of these unusually stable nanowires consists of rigid, functionalized Mo octahedra, connected by flexible, bi-stable sulphur bridges. This structural flexibility translates into a capability to st

F. K. Wilhelm, M. J. Storcz, U. Hartmann, M. R. Geller

This is an introduction to elementary decoherence theory as it is typically applied to superconducting qubits.

Fatih Dougan, Frank Marsiglio

It is common practice to try to understand electron interactions in metals by defining a hierarchy of energy scales. Very often, the Fermi energy is considered the largest, so much so that frequently bandwidths are approximated as infinite. The reasoning is that attention should properly be focused on energy levels near the Fermi level, and details of the ba

Giancarlo Franzese, H. Eugene Stanley

Water is commonly associated to the existence of life. However, there is no clear reason why water should be the only liquid in which life could form and survive. Since the seminal work of L. J. Henderson in 1913, scientists are trying to answer the question about the relation between the unusual properties of water and the existence of life. Here we follow

G. Salis, S. F. Alvarado

It is shown that the Kerr rotation of spin-polarized electrons is modulated by the distance of the electrons from the sample surface. Time-resolved Kerr rotation of optically-excited spin-polarized electrons in the depletion layer of n-doped GaAs displays fast oscillations that originate from an interference between the light reflected from the semiconductor

P. M. R. Brydon, M. Gulacsi

We examine the spinless one-dimensional Falicov-Kimball model (FKM) below half-filling, addressing both the binary alloy and valence transition interpretations of the model. Using a non-perturbative technique, we derive an effective Hamiltonian for the occupation of the localized orbitals, providing a comprehensive description of charge order in the FKM. In

Vadim V. Cheianov, Vladimir I. Fal&#39;ko

We show that an electrostatically created n-p junction separating the electron and hole gas regions in a graphene monolayer transmits only those quasiparticles that approach it almost perpendicularly to the n-p interface. Such a selective transmission of carriers by a single n-p junction would manifest itself in non-local magnetoresistance effect in arrays o

V. H. Dao, M. E. Zhitomirsky

Equilibrium shape and orientation of vortex lattice are studied for an s-wave tetrahedral superconductor in the vicinity of the upper critical field. The phase diagram, which includes transitions between rhombic and rectangular lattices, is constructed in the parameter space of the Ginzburg-Landau functional. The developed theory is applied to the heavy-ferm

Joshua Feinberg

I review aspects of work done in collaboration with A. Zee and R. Scalettar \cite{fz1,fz2,fsz} on complex non-hermitean random matrices. I open by explaining why the bag of tools used regularly in analyzing hermitean random matrices cannot be applied directly to analyze non-hermitean matrices, and then introduce the Method of Hermitization, which solves this

Ido Ben-Dayan, Eran Bouchbinder, Itamar Procaccia

We address the role of the nature of material disorder in determining the roughness of cracks which grow by damage nucleation and coalescence ahead of the crack tip. We highlight the role of quenched and annealed disorders in relation to the length scales $d$ and $ξ_c$ associated with the disorder and the damage nucleation respectively. In two related models

Yi-Kuo Yu, Yi-Cheng Zhang, Paolo Laureti, Lionel Moret

Advances in information technology reduce barriers to information propagation, but at the same time they also induce the information overload problem. For the making of various decisions, mere digestion of the relevant information has become a daunting task due to the massive amount of information available. This information, such as that generated by evalua

R. J. Radwanski, Z. Ropka

We have performed calculations of the electronic structure of LaCoO3 from first principles, assuming the atomistic construction of matter and the electrostatic origin of the crystal-field splitting. In our atomic-like approach QUASST the d electrons of the Co3+ ion in LaCoO3 form the highly-correlated atomic-like system 3d6 with the singlet ground state 1A1

Srutarshi Pradhan, Bikas K. Chakrabarti

In this work we review the precursors of catastrophic avalanches (global failures) in several failure models, namely (a) Fiber Bundle Model (FBM), (b) Random Fuse Model (RFM), (c) Sandpile Models and (d) Fractal Overlap Model. The precursor parameters identified here essentially reflect the growing correlations within such systems as they approach their resp

Andy Thomas, Dirk Meyners, Daniel Ebke, Ning-Ning Liu

A new magnetic logic overcomes the major limitations of field programmable gate arrays while having a 50% smaller unit cell than conventional designs utilizing magnetic tunnel junctions with one Heusler alloy electrode. These show positive and negative TMR values at different bias voltages at room temperature which generally adds an additional degree of free

Alexander Mattausch, Michel Bockstedte, Oleg Pankratov, John W. Steeds

Recent ab initio calculations [Mattausch et al., Phys. Rev. B 70, 235211 (2004)] of carbon clusters in SiC reveal a possible connection between the tricarbon antisite (C_3)_Si and the U photoluminescence center in 6H-SiC [Evans et al., Phys. Rev. B 66, 35204 (2002)]. Yet, some of the predicted vibrational modes were not observed experimentally. Here we repor

R. Feyerherm, E. Dudzik, N. Aliouane, D. N. Argyriou

Synchrotron x-ray diffraction and resonant magnetic scattering experiments on single crystal DyMnO3 have been carried out between 4 and 40 K. Below TN(Dy) = 5K, the Dy magnetic moments order in a commensurate structure with propagation vector 0.5 b*. Simultaneous with the Dy magnetic ordering, an incommensurate lattice modulation with propagation vector 0.90

A. V. Germanenko, G. M. Minkov, A. A. Sherstobitov, O. E. Rut

Results of numerical simulation of the weak localization in two-dimensional systems in wide range of magnetic filed are presented. Three cases are analyzed: (i) the isotropic scattering and randomly distributed scatterers; (ii) the anisotropic scattering and randomly distributed scatterers; (iii) the isotropic scattering and the correlated distribution of th

D. Reguera, G. Schmid, P. S. Burada, J. M. Rubí

We show that transport in the presence of entropic barriers exhibits peculiar characteristics which makes it distinctly different from that occurring through energy barriers. The constrained dynamics yields a scaling regime for the particle current and the diffusion coefficient in terms of the ratio between the work done to the particles and available therma

Tomoya Ono, Shinya Horie, Katsuyoshi Endo, Kikuji Hirose

A scanning tunneling microscopy (STM) image of a hydrogen-adsorbed Si(001) surface is studied using first-principles electron-conduction calculation. The resultant STM image and scanning tunneling spectroscopy spectra are in agreement with experimental results. The contributions of the $π$ states of bare dimers to the tunnel current are markedly large, and t

M. Iskin, C. A. R. Sá de Melo

We analyze the evolution of two-band superfluidity from the weak coupling Bardeen-Cooper-Schrieffer (BCS) to the strong coupling Bose-Einstein condensation (BEC) limit. When the interband interaction is tuned from negative to positive values, a quantum phase transition occurs from a 0-phase to a $π$-phase state, depending on the relative phase of two order p

Branislav K. Nikolic, Liviu P. Zarbo

We show that pure spin Hall current, flowing out of a four-terminal phase-coherent two-dimensional electron gas (2DEG) within inversion asymmetric semiconductor heterostructure, contains contributions from both the extrinsic mechanisms (spin-orbit dependent scattering off impurities) and the intrinsic ones (due to the Rashba coupling). While the extrinsic co

Benjamin Dollet Melanie Durth Francois Graner

To investigate the link between discrete, small-scale and continuous, large scale mechanical properties of a foam, we observe its two-dimensional flow in a channel, around an elliptical obstacle. We measure the drag, lift and torque acting on the ellipse {\it versus} the angle between its major axis and the flow direction. The drag increases with the spanwis

A. Mebrahtu, A. Sanpera, M. Lewenstein

We analyze coherence effects during the splitting of a quasi one-dimensional condensate into two spatially separated ones and their subsequent merging into a single condensate. Our analysis takes into account finite-temperature effects, where phase fluctuations play an important role. We show that, at zero-temperature, the two split condensates can be merged

Yong P. Chen

We study a model of \textit{pinned} bilayer Wigner crystals (WC) and focus on the effects of interlayer coherence (IC) on pinning. We consider both a pseudospin ferromagnetic WC (FMWC) with IC and a pseudospin antiferromagnetic WC (AFMWC) without IC. Our central finding is that a FMWC can be pinned more strongly due to the presence of IC. One specific mechan

A. A. Shashkin, E. V. Deviatov, V. T. Dolgopolov, A. A. Kapustin

In the ballistic regime, the metallic temperature dependence of the conductivity in a two-dimensional electron system in silicon is found to change non-monotonically with the degree of spin polarization. In particular, it fades away just before the onset of complete spin polarization but reappears again in the fully spin-polarized state, being, however, supp

B. L. Zink, R. Islam, David J. Smith, F. Hellman

We report specific heat and thermal conductivity of gadolinium- and yttrium-doped amorphous silicon thin films measured using silicon-nitride membrane-based microcalorimeters. Addition of gadolinium or yttrium to the amorphous silicon network reduces the thermal conductivity over a wide temperature range while significantly increasing the specific heat. This

S. Medina, M. Pena, C. Morisset, G. Stasinska

Expansion velocities (Vexp) of different ions and line widths at the base of the lines are measured and analyzed for 24 PNe with [WC]-type nuclei (WRPNe), 9 PNe ionized by WELS (WLPNe) and 14 ordinary PNe. A comparative study of the kinematical behavior of the sample clearly demonstrates that WRPNe have in average 40-45% larger Vexp, and possibly more turbul

M. E. Putman

Potential condensed clouds of gas in the Galactic halo are examined in the context of the recent models of cooling, fragmenting clouds building up the baryonic mass of the Galaxy. 582 high-velocity clouds (HVCs) are defined as the potential infalling, condensed clouds and the sample&#39;s spatial and velocity distribution are presented. With the majority of

Tsvi Piran, Nir J. Shaviv

Shortly after the discovery of the binary system PSR J0737-3039 we predicted that it has a small proper motion and suggested that this implies that the progenitor mass of the younger pulsar (B) must be around 1.45M_sun. This is in contradiction to standard evolutionary scenarios that suggest a He-star progenitor with M >2.1-2.3M_sun and in sharp contrast to

M. Relano, U. Lisenfeld, E. Battaner, J. M. Vilchez

We investigate the distribution of the intrinsic extinction in NGC1569 using an extinction map derived from the H_alpha/H_beta emission line ratio. We compare the extinction distribution to that of the dust emission traced by SPITZER IRAC(8microns) and MIPS (24microns) maps. The intrinsic extinction shows spatial variations, from zones with negligible extinc

R. A. Laing, J. R. Canvin, W. D. Cotton, A. H. Bridle

Our modelling of FR I radio jets as decelerating, relativistic flows allows us to derive their orientations accurately. We present images of Faraday rotation for two of these these objects (3C 31 and NGC 315) and show that the fluctuations of rotation measure (RM) are larger in the fainter (receding) jets, as expected if the rotation occurs in the hot galaxy

C. Ngeow, S. Kanbur

It is well-known that the peak brightness of the Type Ia supernovae calibrated with Cepheid distances can be used to determine the Hubble constant. The Cepheid distances to host galaxies of the calibrating supernovae are usually obtained using the period-luminosity (PL) relation derived from Large Magellanic Cloud (LMC) Cepheids. However recent empirical stu

Ralf Napiwotzki

A recent spectroscopic analysis of central stars of planetary nebulae (CSPNe) claims that the sample includes five CSPNe with masses very close to the Chandrasekhar limit of white dwarfs. This claim should be verified or discarded from the available kinematical and chemical abundance information. Kinematical parameters are extracted from Galactic orbits and

A. C. Goncalves, S. Collin, A. -M. Dumont, M. Mouchet

(Abridged) Many active galactic nuclei exhibit X-ray features typical of the highly ionized gas called &#34;Warm Absorber&#34; (WA). Such a material appears to be stratified, displaying zones of different density, temperature, and ionization. In this paper, we investigate the possibility of modelling the WA gas in NGC 3783 as a single medium in total pressur

M. Mouhcine, S. P. Bamford, A. Aragon-Salamanca, O. Nakamura

We examine the evolutionary status of luminous, star-forming galaxies in intermediate-redshift clusters by considering their star formation rates and the chemical and ionsiation properties of their interstellar emitting gas. Our sample consists of 17 massive, star-forming, mostly disk galaxies with M_{B}<-20, in clusters with redshifts in the range 0.31< z <

M. Mouhcine, S. P. Bamford, A. Aragon-Salamanca, O. Nakamura

We derive oxygen abundances for a sample of 40 luminous (M_{B} < -19), star-forming, mostly disk, field galaxies with redshifts in the range 0.2 < z < 0.8$, with a median of <z> = 0.45. Oxygen abundances, relative to hydrogen, of the interstellar emitting gas are estimated by means of the empirically calibrated strong emission line ratio technique. The deriv

P. A. Evans, Coel Hellier, Gavin Ramsay

The intermediate polar PQ Geminorum shows a complex pulsation, caused by a spinning white dwarf, which varies markedly with wavelength. We report XMM-Newton observations, including the soft and hard X-ray bands and the first UV lightcurves of this star. We update the ephemeris for PQ Gem allowing us to align these data with a compilation of lightcurves from

M. Wold, E. Galliano

We report on the discovery of several compact regions of mid-infrared emission in the starforming circum nuclear disk of the starburst/Seyfert2 galaxy NGC7582. The compact sources do not have counterparts in the optical and near-infrared, suggesting that they are deeply embedded in dust. We use the [NeII]12.8 micron line emission to estimate the emission mea

Ian Smail

I discuss our current understanding of the properties and nature of high redshift, far-infrared luminous galaxies selected through their observed-frame submillimeter emission.

A. Olech, K. Mularczyk, P. Kedzierski, K. Zloczewski

We report on extensive photometry of the dwarf nova SS Ursae Minoris throughout nine months of 2004. In total, we recorded two superoutbursts and 11 normal outbursts of the star. SS UMi has been known to show frequent superoutbursts with a mean interval of 84.7 days. Our data suggest that the interval between successive superoutbursts lengthened to 197 days,

P. B. Tissera, C. Scannapieco, S. D. M. White, V. Springel

We present a Supernova (SN) feedback model that succeeds at describing the chemical and energetic effects of SN explosions in galaxy formation simulations. This new SN model has been coupled to GADGET-2 and works within a new multiphase scheme which allows the description of a co-spatial mixture of cold and hot interstellar medium phases. No ad hoc scale-dep

Kiyotomo Ichiki, Keitaro Takahashi, Hiroshi Ohno, Hidekazu Hanayama

The origin of the substantial magnetic fields that are found in galaxies and on even larger scales, such as in clusters of galaxies, is yet unclear. If the second-order couplings between photons and electrons are considered, then cosmological density fluctuations, which explain the large scale structure of the universe, can also produce magnetic fields on co

G. Giardino, F. Favata, B. Silva, G. Micela

We present the results of a five-day monitoring campaign with XMM-Newton of six X-ray bright young stellar objects (YSOs) in the star-forming complex L1551 in Taurus. All stars present significant variability on the five-day time scale. Modulation of the light curve on time scales comparable with the star&#39;s rotational period appeared to be present in the

R. J. Beswick, J. D. Riley, I. Marti-Vidal, A. Pedlar

We present the results of a second epoch of 18cm global Very Long-Baseline Interferometry (VLBI) observations, taken on 23 February 2001, of the central kiloparsec of the nearby starburst galaxy Messier 82. These observations further investigate the structural and flux evolution of the most compact radio sources in the central region of M82. The two most com

Karl M. Menten

While clearly the main scientific targets of &#39;&#39;z-machines&#34; will be redshifted lines of carbon monoxide, there also exist other interesting applications. Here scientific and technological aspects of observing lines from CO and other species at high redshift and in the local universe are discussed as are the limitations of such efforts and prospect

D. J. Pisano, D. Barnes, B. Gibson, L. Staveley-Smith

We present the results of our HI survey of six loose groups of galaxies analogous to the Local Group. The survey was conducted using the Parkes telescope and the Australia Telescope Compact Array to produce a census of all the gas-rich galaxies and potential analogs to the high-velocity clouds (HVCs) within these groups down to M(HI)<10^7 M(sun) as a test of