March 2003 arXiv papers

Katrin Becker, Melanie Becker, Keshav Dasgupta, Sergey Prokushkin

We study the superpotential for the heterotic string compactified on non-Kahler complex manifolds. We show that many of the geometrical properties of these manifolds can be understood from the proposed superpotential. In particular we give an estimate of the radial modulus of these manifolds. We also show, how the torsional constraints can be obtained from t

Y. Burak, G. Ariel, D. Andelman

We address theoretically aggregation of DNA segments by multivalent polyamines such as spermine and spermidine. In experiments, the aggregation occurs above a certain threshold concentration of multivalent ions. We demonstrate that the dependence of this threshold on the concentration of DNA has a simple form. When the DNA concentration c_DNA is smaller than

L. Velazquez, F. Guzman

Astrophysical systems will never be in a real Thermodynamic equilibrium: they undergo an evaporation process due to the fact that the gravity is not able to confine the particles. Ordinarily, this difficulty is overcome by enclosing the system in a rigid container which avoids the evaporation. We proposed an energetic prescription which is able to confine th

M. Magliocchetti, C. Porciani

We use the clustering results obtained by Madgwick et al. (2003) for a sample of 96,791 2dF galaxies with redshift 0.01 \lt z \lt 0.15 to study the distribution of late-type and early-type galaxies within dark matter haloes of different mass. Within the framework of our models, galaxies of both classes are found to be as spatially concentrated as the dark ma

Carlo R. Contaldi, Marco Peloso, Lev Kofman, Andrei Linde

The Cosmic Microwave Background (CMB) anisotropy power on the largest angular scales observed both by WMAP and COBE DMR appears to be lower than the one predicted by the standard model of cosmology with almost scale free primordial perturbations arising from a period of inflation \cite{cobe,Bennett:2003bz,Spergel,Peiris}. One can either interpret this as a m

Oscar Loaiza-Brito

We propose an M-theory lift picture of the exchange among type IIA orientifold two-planes. This consists in wrapping a M5-brane on a three-cycle in the transverse space of the M-theory orientifold plane OM2. A flux quantization condition for the three-form self-dual field strength, on the worldvolume of the M5-brane is computed. This condition establishes th

J. Socorro, M. A. Reyes, F. A. Gelbert

We apply the technique of standard supersymmetric factorization for any q factor ordering in the Wheeler-DeWitt (WDW) equation for barotropic Friedmann-Robertson-Walker (FRW) minisuperspace model, including the cosmological term. The resulting wave functions of the universe are exhibited as one-parameter families, which for particular values of the $γ$ param

D. A. Demir

In minimal supersymmetric model (SUSY) with a light Higgs sector, explicit CP violation and most general flavor mixings in the sfermion sector, integration of the superpartners out of the spectrum induces potentially large contributions to the Yukawa couplings of light quarks via those of the heavier ones. These corrections can be sizeable even for moderate

K. Huitu, J. Laamanen, P. N. Pandita

We derive the general upper bounds on the mass of the lightest neutralino, as a function of the gluino mass, in different supersymmetry breaking models with minimal particle content and the standard model gauge group. This includes models with gravity mediated supersymmetry breaking (SUGRA), as well as models with anomaly mediated supersymmetry breaking (AMS

Klaus Behrndt, Mirjam Cvetic

We obtain a general class of time-dependent, asymptotically de Sitter backgrounds which solve the first order bosonic equations that extremize the action for supergravity with gauged non-compact $R$-symmetry. These backgrounds correspond only to neutral fields with the correct sign of kinetic energy. Within N=2 five-dimensional supergravity with vector-super

S. G. Naculich, H. J. Schnitzer, N. Wyllard

We study the matrix model/gauge theory connection for three different N=1 models: U(N) x U(N) with matter in bifundamental representations, U(N) with matter in the symmetric representation, and U(N) with matter in the antisymmetric representation. Using Ward identities, we explicitly show that the loop equations of the matrix models lead to cubic algebraic c

S. A. Bulgadaev

The duality relation for the effective conductivity sigma_{e} of 2D isotropic heterophase systems is used for obtaining the exact results for sigma_{e} at arbitrary number of phases N. The exact values of sigma_{e} correspond to the fixed points of the duality transformations. The new exact results for sigma_{e}, generalizing the well-known exact values of s

L. Fallani, F. S. Cataliotti, J. Catani, C. Fort

We report the experimental observation of a lensing effect on a Bose-Einstein condensate expanding in a moving 1D optical lattice. The effect of the periodic potential can be described by an effective mass dependent on the condensate quasi-momentum. By changing the velocity of the atoms in the frame of the optical lattice we induce a focusing of the condensa

Dominik Düchs, Venkat Ganesan, Glenn H. Fredrickson, Friederike Schmid

We present a Monte Carlo approach to incorporating the effect of thermal fluctuations in field theories of polymeric fluids. This method is applied to a field-theoretic model of a ternary blend of AB diblock copolymers with A and B homopolymers. We find a shift in the line of order-disorder transitions from their mean-field values, as well as strong signatur

P. B. Ivanov, J. C. B. Papaloizou

In this paper we develop a theory of disturbances induced by the stellar tidal field in a fully convective slowly rotating planet orbiting on a highly eccentric orbit around a central star. We show that there are two contributions to the mode energy and angular momentum gain due to impulsive tidal interaction: a) 'the quasi-static' contribution which

Holger Gies, Kurt Langfeld, Laurent Moyaerts

We develop a method to compute the Casimir effect for arbitrary geometries. The method is based on the string-inspired worldline approach to quantum field theory and its numerical realization with Monte-Carlo techniques. Concentrating on Casimir forces between rigid bodies induced by a fluctuating scalar field, we test our method with the parallel-plate conf

The BABAR Collaboration, B. Aubert

We present measurements of the branching fractions of the decays B+ -> eta' K+ and B0 -> eta' K0. For B0 -> eta' K0s we also measure the time dependent CP-violation parameters S and C, and for B+ ->eta' K+ the time-integrated charge asymmetry Ach. The data sample corresponds to 88.9 million BBbar pairs produced by e+e- annihilation at the Upsillon(4S). The r

G. Baskaran

Takada et al. have reported superconductivity in layered $Na__x CoO_2.yH_2O$ ($T_c \approx5 K$) and more recently Wen et al. in $A_xCoO_{2+δ}$ ($A = Na,K$)(\tc$\approx~31 K$). We model a reference neutral \cob layer as an orbitally non-degenerate spin-\half antiferromagnetic Mott insulator on a triangular lattice and $Na__x CoO_2.yH_2O$ and $A_xCoO_{2+δ}$ as

C. Maieron, M. C. Martínez, J. A. Caballero, J. M. Udías

The quasielastic scattering of muon neutrinos on oxygen 16 is studied for neutrino energies between 200 MeV and 1 GeV using a relativistic shell model. Final state interactions are included within the distorted wave impulse approximation, by means of a relativistic optical potential, with and without imaginary part, and of a relativistic mean field potential

Sanjeev S. Seahra, H. R. Sepangi, J. Ponce de Leon

Motivated by the Randall-Sundrum brane-world scenario, we discuss the classical and quantum dynamics of a (d+1)-dimensional boundary wall between a pair of (d+2)-dimensional topological Schwarzschild-AdS black holes. We assume there are quite general -- but not completely arbitrary -- matter fields living on the boundary ``brane universe'' and its ge

V. Suneeta

Quasinormal modes for scalar field perturbations of a Schwarzschild-de Sitter (SdS) black hole are investigated. An analytical approximation is proposed for the problem. The quasinormal modes are evaluated for this approximate model in the limit when black hole mass is much smaller than the radius of curvature of the spacetime. The model mirrors some strikin

Zhenyang Zhong, A. Halilovic, M. Muhlberger, F. Schaffler

Self-assembled Ge islands were grown on stripe-patterned Si (001) substrates by solid source molecular beam epitaxy. The surface morphology obtained by atomic force microscopy (AFM) and cross-sectional transmission electron microscopy images (TEM) shows that the Ge islands are preferentially grown at the sidewalls of pure Si stripes along [-110] direction at

Y. G. Ma, R. Wada, K. Hagel, J. Wang

A wide variety of observables indicate that maximal fluctuations in the disassembly of hot nuclei with A ~ 36 occur at an excitation energy of 5.6 +- 0.5 MeV/u and temperature of 8.3 +- 0.5 MeV. Associated with this point of maximal fluctuations are a number of quantitative indicators of apparent critical behavior. The associated caloric curve does not appea

Ya. G. Ponomarev, S. A. Kuzmichev, M. G. Mikheev, M. V. Sudakova

The break-junction tunneling has been systematically investigated in MgB2. Two types of the break-junction contacts have been exploited on the same samples, which demonstrated tunnel contact like (SIS) and point contact like (SnS) behavior. Both of them have shown the existence of the two distinct energy gaps. We have observed also the peculiarities on the I

Jonathan Barrett, Serge Massar

We discuss the security implications of noise for quantum coin tossing protocols. We find that if quantum error correction can be used, so that noise levels can be made arbitrarily small, then reasonable security conditions for coin tossing can be framed so that results from the noiseless case will continue to hold. If, however, error correction is not avail

P. Exner, K. Yoshitomi

Given $n\geq 2$, we put $r=\min\{i\in\mathbb{N}; i>n/2 \}$. Let $Σ$ be acompact, $C^{r}$-smooth surface in $\mathbb{R}^{n}$ which contains the origin. Let further $\{S_ε\}_{0\leε<η}$ be a family of measurable subsets of $Σ$ such that $\sup_{x\in S_ε}|x|= {\mathcal O}(ε)$ as $ε\to 0$. We derive an asymptotic expansion for the discrete spectrum of the Schr{ö}d

M. Rodriguez, P. Torma

The possibility of Bloch oscillations for a degenerate and superfluid Fermi gas of atoms in an optical lattice is considered. For a one-component degenerate gas the oscillations are suppressed for high temperatures and band fillings. For a two-component gas the Landau criterion is used for specifying the regime where Bloch oscillations of the superfluid may

Anindya Datta, Emidio Gabrielli, Barbara Mele

In the framework of quantum gravity propagating in large extra dimensions, the effects of virtual Kaluza-Klein graviton and graviscalar interference with Higgs boson production amplitudes are computed at linear colliders and Higgs factories. The interference of the almost-continuous spectrum of the KK gravitons with the standard model resonant amplitude is f

Hans Schoutens

In this paper, various Homological Conjectures are studied for local rings which are locally finitely generated over a discrete valuation ring $V$ of mixed characteristic. Typically, we can only conclude that a particular Conjecture holds for such a ring provided the residual characteristic of $V$ is sufficiently large in terms of the complexity of the data,

Daniel K. L. Oi

We show how interferometry can be used to characterise certain aspects of general quantum processes, in particular, the coherence of completely positive maps. We derive a measure of coherent fidelity, maximum interference visibility and the closest unitary operator to a given physical process under this measure.

L. Roa, A. Delgado, I. Fuentes-Guridi

Quantum teleportation of qudits is revisited. In particular, we analyze the case where the quantum channel corresponds to a non-maximally entangled state and show that the success of the protocol is directly related to the problem of distinguishing non-orthogonal quantum states. The teleportation channel can be seen as a coherent superposition of two channel

E. L. Bolda, E. Tiesinga, P. S. Julienne

We describe a model for s-wave collisions between ground state atoms in optical lattices, considering especially the limits of quasi-one and two dimensional axisymmetric harmonic confinement. When the atomic interactions are modelled by an s-wave Fermi-pseudopotential, the relative motion energy eigenvalues can easily be obtained. The results show that excep

Dominik Janzing, Pawel Wocjan, Thomas Beth

We introduce the quantum complexity class FQMA. This class describes the complexity of generating a quantum state that serves as a witness for a given QMA problem. In a certain sense, FQMA is the quantum analogue of FNP (function problems associated with NP). The latter describes the complexity of finding a succinct proof for a NP decision problem. Whereas a

L. Accardi, S. V. Kozyrev

A 2-level atom with degenerate ground state interacting with a quantum field is investigated. We show, that the field drives the state of the atom to a stationary state, which is non-unique, but depends on the initial state of the system through some conserved quantities. This non-uniqueness follows from the degeneracy of the ground state of the atom, and wh

Dagmar Bruss, Matthias Christandl, Artur Ekert, Berthold-Georg Englert

The security of a cryptographic key that is generated by communication through a noisy quantum channel relies on the ability to distill a shorter secure key sequence from a longer insecure one. For an important class of protocols, which exploit tomographically complete measurements on entangled pairs of any dimension, we show that the noise threshold for cla

Marco A. Pravia, Zhiying Chen, Jeffrey Yepez, David G. Cory

We report an ensemble nuclear magnetic resonance (NMR) implementation of a quantum lattice gas algorithm for the diffusion equation. The algorithm employs an array of quantum information processors sharing classical information, a novel architecture referred to as a type-II quantum computer. This concrete implementation provides a test example from which to

B. Zhilinskii

The analogy between monodromy in dynamical (Hamiltonian) systems and defects in crystal lattices is used in order to formulate some general conjectures about possible types of qualitative features of quantum systems which can be interpreted as a manifestation of classical monodromy in quantum finite particle (molecular) problems.

Warwick P. Bowen, Nicolas Treps, Roman Schnabel, Timothy C. Ralph

We generate and characterise continuous variable polarization entanglement between two optical beams. We first produce quadrature entanglement, and by performing local operations we transform it into a polarization basis. We extend two entanglement criteria, the inseparability criteria proposed by Duan {\it et al.}\cite{Duan00} and the Einstein-Podolsky-Rose

L. S. Matthews, T. W. Hyde

Saturn&#39;s dynamic F-Ring still presents a challenge for understanding and explaining the kinematic processes that lead to the changing structure visible in our observations of this ring. This study examines the effect of Saturn&#39;s magnetic field on the dynamics of micron-sized grains that may become electrically charged due to interaction with plasma i

Cheng Yang

We use boundary-integral methods to compute the time-dependent deformation of a drop of dielectric fluid immersed in another dielectric fluid in a uniform electric field E. Steady state theory predicts, when the permittivity ratio, β, is large enough, a conical interface can exist at two cone angles, with θ_<(β) stable and θ_>(β) unstable. Our numerical evid

Calvin W. Johnson

Two important pieces of nuclear structure are many-body collective deformations and single-particle spin-orbit splitting. The former can be well-described microscopically by simple SU(3) irreps, but the latter mixes SU(3) irreps, which presents a challenge for large-scale, ab initio calculations on fast modern computers. Nonetheless, SU(3)-like phenomenology

Patrick N. McGraw, Michael Menzinger

We outline a general theory for the analysis of flow-distributed standing and travelling wave patterns in one-dimensional, open plug-flows of oscillatory chemical media. We treat both the amplitude and phase dynamics of small and large-amplitude waves, considering both travelling and stationary waves on an equal footing and emphasizing features that are gene

Radha Balakrishnan, Indubala Satija

We characterize the geometrical and topological aspects of a dynamical system by associating a geometric phase with a phase space trajectory. Using the example of a nonlinear driven damped oscillator, we show that this phase is resilient to fluctuations, responds to all bifurcations in the system, and also finds new geometric transitions. Enriching the phase

John D. Barrow, Janna Levin

A simple new binary test for chaos has been proposed by Gottwald and Melbourne. We apply this test successfully to the Henon-Heiles and Lorenz systems, demonstrating its applicability to conservative systems, as well as dissipative systems. The binary test is effective for highly chaotic Hamiltonian systems and orbits on a strange attractor and is particular

Michael Atiyah, Paul Sutcliffe

In this article we review some problems in physics, chemistry and mathematics that lead naturally to a class of polyhedra which include the Platonic solids. Examples include the study of electrons on a sphere, cages of carbon atoms, central configurations of gravitating point particles, rare gas microclusters, soliton models of nuclei, magnetic monopole scat

Estelle L. Basor, Torsten Ehrhardt, Harold Widom

We establish an asymptotic formula for determinants of truncated Wiener-Hopf+Hankel operators with symbol equal to the exponential of a constant times the characteristic function of an interval. This is done by reducing it to the corresponding (known) asymptotics for truncated Toeplitz+Hankel operators. The determinants in question arise in random matrix the

Bernard Leclerc, Hyohe Miyachi

We give closed formulas for all vectors of the canonical basis of a level 2 irreducible integrable representation of $U_v(sl_\infty)$. These formulas coincide at v=1 with Lusztig&#39;s formulas for the constructible characters of the Iwahori-Hecke algebras of type B and D.

Yukihide Takayama

Let K be a field and S = K[x1,...,xn] be a polynomial ring. A single spot ideal I =< S is a graded ideal whose local cohomology H^i_\mm(S/I), i< dim S/I and \mm = (x1,...,xn), only has non-trivial value N, a finite length module, at i = depth S/I. We consider characterization of single spot ideals in terms of (long) Bourbaki sequences. The codimension 2 case

G. J. Chaitin

Most work on computational complexity is concerned with time. However this course will try to show that program-size complexity, which measures algorithmic information, is of much greater philosophical significance. I&#39;ll discuss how one can use this complexity measure to study what can and cannot be achieved by formal axiomatic mathematical theories. In

Guy Roos, Weiping Yin

We introduce two classes of &#34;egg type&#34; domains, built on general bounded symmetric domains, for which we compute the Bergmann kernel in explicit form. We use the characterization of bounded symmetric domains through Jordan triple systems. The egg type domains are defined using the generic norm. A generalization of the Hua integral is computed; the re

Francisco Santos, Bernd Sturmfels

Any configuration of lattice vectors gives rise to a hierarchy of higher-dimensional configurations which generalize the Lawrence construction in geometric combinatorics. We prove finiteness results for the Markov bases, Graver bases and face posets of these configurations, and we discuss applications to the statistical theory of log-linear models.

Ilka Agricola, Roe Goodman

When $G$ is a complex reductive algebraic group and $G/K$ is a reductive symmetric space, the decomposition of $\C[G/K]$ as a $K$-module was obtained (in a non-constructive way) by Richardson, generalizing the celebrated result of Kostant-Rallis for the linearized problem (the harmonic decomposition of the isotropy representation). To obtain a constructive v

Bernard Leclerc, Maxim Nazarov, Jean-Yves Thibon

A criterion of irreducibility for induction products of evaluation modules of type A affine Hecke algebras is given. It is derived from multiplicative properties of the canonical basis of a quantum deformation of the Bernstein-Zelevinsky ring.

Nicholas T. Jones, Horace Stoica, S. -H. Henry Tye

Brane inflation in superstring theory predicts that cosmic strings (but not domain walls or monopoles) are produced towards the end of the inflationary epoch. Here, we discuss the production, the spectrum and the evolution of such cosmic strings, properties that differentiate them from those coming from an abelian Higgs model. As D-branes in extra dimensions

Flavio S. Nogueira, Asle Sudbo

We propose a mechanism by which electric charges deconfine in an Abelian Higgs model with matter fields belonging to the fundamental representation of the gauge group. Kosterlitz-Thouless like recursion relations for a scale-dependent stiffness parameter and fugacity are given, showing that for a logarithmic potential between point charges in any dimension,

Anjan Kundu

The aim of this review is to present the list of by now a significant collection of quantum integrable models, ultralocal as well as nonultralocal, in a systematic way stressing on their underlying unifying algebraic structures. We restrict to quantum and statistical models belonging to trigonometric and rational classes with (2 x 2)- Lax operators. The ultr

Kai Kratzert

We investigate the breakdown of supersymmetry at finite temperature. While it has been proven that temperature always breaks supersymmetry, the nature of this breaking is less clear. On the one hand, a study of the Ward-Takahashi identities suggests a spontaneous breakdown of supersymmetry without the existence of a Goldstino, while on the other hand it has

A. Prikas, N. D. Tracas

We investigate the phase space of parameters in the Pati-Salam model derived in the context of D-branes scenarios, requiring low energy string scale. We find that a non-supersymmetric version complies with a string scale as low as 10 TeV, while in the supersymmetric version the string scale raises up to ~2 x 10^7 TeV. The limited energy region for RGE runnin

C. Carimalo, A. Schiller, V. G. Serbo

As continuation of our previous paper we further develop our new method for calculating helicity amplitudes of jet-like QED processes described by tree diagrams, applying it to lepton pair production. This method consists in replacing spinor structures for real and weakly virtual intermediate leptons by simple transition vertices. New vertices are introduced

Yoshio Koide, Hiroyuki Nishiura, Koichi Matsuda, Tatsuru Kikuchi

Against the conventional picture that the mass matrix forms in the quark sectors will take somewhat different structures from those in the lepton sectors, a possibility that all the mass matrices of quarks and leptons have the same form as in the neutrinos is investigated. For the lepton sectors, the model leads to a nearly bimaximal mixing with the predicti

Motomichi Harada, Stephen Pinsky

We present a formulation of N=(1,1), Super Yang-Mills theory in 2+1 dimensions using a transverse lattice methods that exactly preserves one supersymmetry. First, using a Lagrangian approach we obtain a standard transverse lattice formulation of the Hamiltonian. We then show that the Hamiltonian also can be written discretely as the square of a supercharge a

Gabriela Gonzalez

At the time of this conference, in June 2002, The LIGO Science Collaboration was getting ready to perform its first Science Run, where data will be taken with all three LIGO detectors. We describe here the status of the LIGO detectors as of February 2003, their performance during the ``Engineering Run&#39;&#39; E7 (Dec 28&#39;01-Jan 14&#39;02) and subsequent

Abel Camacho, Alfredo Macias

From the latest experimental readouts in this context an intriguing discrepancy has been elicited. Indeed, theory and experiment dissent by one per cent, and though this fact could be a consequence of the mounting of the experimental device, it might also embody a difference between the way in which gravity behaves in classical and quantum mechanics. In this

Norman G. Vinson

Unfamiliar, large-scale virtual environments are difficult to navigate. This paper presents design guidelines to ease navigation in such virtual environments. The guidelines presented here focus on the design and placement of landmarks in virtual environments. Moreover, the guidelines are based primarily on the extensive empirical literature on navigation in

Christian Igel, Marc Toussaint

The sharpened No-Free-Lunch-theorem (NFL-theorem) states that the performance of all optimization algorithms averaged over any finite set F of functions is equal if and only if F is closed under permutation (c.u.p.) and each target function in F is equally likely. In this paper, we first summarize some consequences of this theorem, which have been proven rec

G. M. Grason, B. A. DiDonna, R. D. Kamien

We analyze the energetics of sphere-like micellar phases in diblock copolymers in terms of well-studied, geometric quantities for their lattices. We argue that the A15 lattice with Pm3n symmetry should be favored as the blocks become more symmetric and corroborate this through a self-consistent field theory. Because phases with columnar or bicontinuous topol

Markus Deserno

When a colloidal particle adheres to a fluid membrane, it induces elastic deformations in the membrane which oppose its own binding. The structural and energetic aspects of this balance are theoretically studied within the framework of a Helfrich Hamiltonian. Based on the full nonlinear shape equations for the membrane profile, a line of continuous binding t

Nguyen H. Phuong, Friederike Schmid

By computer simulations of systems of ellipsoids, we study the influence of the isotropic/nematic phase transition on the direct correlation functions (DCF) in anisotropic fluids. The DCF is determined from the pair distribution function by solving the full Ornstein-Zernike equation, without any approximations. Using a suitable molecular-fixed reference fram

G. Foffi, W. Gotze, F. Sciortino, P. Tartaglia

We report extensive molecular-dynamics simulation results for binary mixtures of hard spheres for different size disparities and different mixing percentages,for packing fractions up to 0.605 and over a characteristic time interval spanning up to five orders in magnitude. We explore the changes in the evolution of glassy dynamics due to mixing and discover t

K. Binder

In their comment to the paper ``Theory of the evaporation/condensation transition of equilibrium droplets in finite volumes&#39;&#39; [Physica A, 319, 99 (2003)], Biskup et al. claim that in finite systems at fixed density ``the physical significance of the conjugate thermodynamic variable is of dubious value&#39;&#39;. This claim is critically discussed.

M. J. Lopez, A. Rubio, J. A. Alonsos

Structural and thermal characteristics of crystalline ropes of single-wall carbon nanotubes (SWCNTs) are investigated. Novel crystalline ropes of polygonized SWCNTs produced by laser irradiation exhibit rounded-hexagonal cross sections in contrast to earlier observations of circular tubes. Extensive molecular dynamics (MD) simulations lead to several metasta

Daniele Varsano, M. A. L. Marques, Angel Rubio

We present calculations on energy- and time-resolved two-photon photoemission spectra of images states in Cu(100) and Cu(111) surfaces. The surface is modeled by a 1D effective potential and the states are propagated within a real-space, real-time method. To obtain the energy resolved spectra we employ a geometrical approach based on a subdivision of space i

Kyungwha Park, Mark R. Pederson, Steven L. Richardson, Nuria Aliaga-Alcalde

The dimeric form of the single-molecule magnet [Mn$_4$O$_3$Cl$_4$(O$_2$CEt)$_3$(py)$_3$]$_2$ recently revealed interesting phenomena: no quantum tunneling at zero field and tunneling before magnetic field reversal. This is attributed to substantial antiferromagnetic exchange interaction between different monomers. The intermolecular exchange interaction, ele

P. Samuely, Z. Holanova, P. Szabo, J. Kacmarcik

The Andreev reflection measurements of the superconducting energy gap in the carbon-substituted MgB$_2$ are presented. Despite the strong suppression of the transition temperature by 17 K in comparison with the pure MgB$_2$, the same reduced value of the small superconducting energy gap with $2Δ/kT_c \approx$ 1.7 has been systematically observed. This indica

P. Virnau, L. G. MacDowell, M. Mueller, K. Binder

A fluid in the NVT ensemble at T less than the critical temperature T_c and rho = N/V somewhat in excess of rho_coex (density of the saturated gas in the gas-liquid transition) is considered. For V->infinity, a macroscopic liquid droplet coexists with surrounding saturated gas according to the lever rule. For finite V, droplets can only exist if they exceed

S. Tsuda, T. Yokoya, Y. Takano, H. Kito

The superconducting gap of MgB2 has been studied by high-resolution angle-resolved photoemission spectroscopy (ARPES). The momentum(k)-resolving capability of ARPES enables us to identify the s- and p-orbital derived bands predicted from band structure calculations and to successfully measure the superconducting gap on each band. The results show that superc

Lazaros K. Gallos, Bijan Movaghar, Laurens D. A. Siebbeles

The many-body Monte Carlo method is used to evaluate the frequency dependent conductivity and the average mobility of a system of hopping charges, electronic or ionic on a one-dimensional chain or channel of finite length. Two cases are considered: the chain is connected to electrodes and in the other case the chain is confined giving zero dc conduction. The

Hans C. Fogedby

Using the previously developed canonical phase space approach applied to the noisy Burgers equation in one dimension, we discuss in detail the growth morphology in terms of nonlinear soliton modes and superimposed linear modes. We moreover analyze the non-Hermitian character of the linear mode spectrum and the associated dynamical pinning and mode transmutat

M. V. Nedoboiko

The local induction approximation (LIA) of the Biot-Savart law is often used for numerical and analytical investigations of vortex dynamics in the theory of superfluid turbulence. In this paper, using numerical simulation, some features of the LIA is considered. The temporal evolution of vortex loop spectrum is studied numerically.

A. W. Ghosh, S. Datta

We discuss the factors that determine the overall shape and magnitude of the current-voltage (I-V) characteristics of a variety of molecular conductors sandwiched between two metallic contacts. We analyze the individual influences of the contact geometry, the molecular chemistry, the electrostatics of the environment, and charging on molecular conduction. Cu

E. V. Gorbar, V. P. Gusynin, V. A. Miransky, I. A. Shovkovy

We derive the effective potential for composite fields in a class of (quasi-) planar models with long-range interactions. This class of models can be relevant for high temperature superconductors and graphite. The fractal structure of the effective potential is revealed and its physical interpretation is presented. It is argued that the multi-branched fracta

Markus Deserno, Felipe Jimenez-Angeles, Christian Holm, Marcelo Lozada-Cassou

A study of a model rod-like polyelectrolyte molecule immersed into a monovalent or divalent electrolyte is presented. Results from the hypernetted-chain/mean spherical approximation (HNC/MSA) theory, for inhomogeneous charged fluids, {\ch are} compared with molecular dynamics (MD) simulations. As a particular case, the parameters of the polyelectrolyte molec

Fred C. Adams, David S. Graff, Manasse Mbonye, Douglas O. Richstone

Motivated by the observed correlation between black hole masses $\mbh$ and the velocity dispersion $σ$ of host galaxies, we develop a theoretical model of black hole formation in galactic bulges (this paper generalizes an earlier ApJ Letter). The model assumes an initial state specified by a a uniform rotation rate $Ω$ and a density distribution of the form

Patrick A. Woudt, Brian Warner

The recurrent nova IM Nor is found to have an orbital period of 2.462 h, shown by periodic dips in brightness. This is only the second recurrent nova known to have such a short period. We interpret the light curve as largely produced by a reflection effect from the heated face of the secondary star, probably with addition of a partial eclipse of the accretio

Eric V. Linder

Mapping the expansion of the universe gives clues to the underlying physics causing the recently discovered acceleration of the expansion, and enables discrimination among cosmological models. We examine the utility of measuring the rate of expansion, H(z), at various epochs, both alone and in combination with distance measurements. Due to parameter degenera

D. S. Madgwick, E. Hawkins, O. Lahav, S. Maddox

We have calculated the two-point correlation functions in redshift space, xi(sigma,pi), for galaxies of different spectral types in the 2dF Galaxy Redshift Survey. Using these correlation functions we are able to estimate values of the linear redshift-space distortion parameter, beta = Omega_m^0.6/b, the pairwise velocity dispersion, a, and the real-space co

Jesús Falcón-Barroso, Marc Balcells, Reynier F. Peletier, Alexandre Vazdekis

We present minor axis kinematic profiles for a well-studied sample of 19 early- to intermediate-type disk galaxies. We introduce, for the first time, the use of single-burst stellar population (SSP) models to obtain stellar velocities, velocity dispersions and higher order Gauss-Hermite moments (h3,h4) from galaxy spectra in the near-infrared Ca II triplet r

Tod E. Strohmayer, Richard F. Mushotzky

We report the discovery with the EPIC CCD cameras onboard XMM-Newton of a 54 mHz quasiperiodic oscillation (QPO) in the > 2 keV X-ray flux from an ultraluminous X-ray source (ULX) in the starburst galaxy M82. This is the first detection of a QPO in the X-ray flux from an extra-Galactic ULX, and confirms that the source is a compact object. Based on the QPO s

Simone Migliari, Tomaso Belloni

We have analysed 16 observations of class beta of GRS 1915+105 performed with the Rossi X-ray Timing Explorer. We show the time-resolved evolution (every 16 seconds) of the X-ray spectral parameters during these observations. The three model independent states (A, B, C) identified in the color-color diagrams are described here in terms of the more physical (

S. Toft, K. Pedersen, H. Ebeling, J. Hjorth

We report the discovery of an overdensity of faint red galaxies in the vicinity of the z=1.786 radio galaxy 3C 294. The overdensity, discovered in a 84 min Ks-band ISAAC/VLT image is significant at the 2.4 sigma level (compared to the local field density), and overlaps with the extended X-ray emission around 3C 294 detected with the Chandra X-ray Observatory

Angela Bragaglia, Monica Tosi

We present CCD BV photometry of the intermediate age open cluster Collinder 110, a nearby, scarcely populated, and poorly studied system. There is no literature information on the metallicity, so we tested several possibilities, and found a slight evidence of sub-solar abundances. Using the synthetic Colour - Magnitude Diagrams technique we estimate the foll

Eric van der Swaluw

Magnetohydrodynamical simulations are presented of a magnetized pulsar wind interacting directly with the interstellar medium, or, in the case of a surrounding supernova remnant, with the associated freely expanding ejecta of the progenitor star. In both cases the simulations show that the pulsar wind nebula will be elongated due to the dynamical influence o

Philipp Podsiadlowski

One promising method to test progenitor models for Type Ia supernovae is to identify surviving companion stars in historical supernova remnants. A surviving companion will have been strongly affected by its interaction with the supernova ejecta. Here we systematically explore the evolution and appearance of a typical companion star that has been stripped and

Eugeny Babichev, Vyacheslav Dokuchaev

We calculate the gravitational radiation from a cusp of the chiral cosmic strings as a function of the current on the string in the limit of small values of the current. The smoothing of the cosmic string cusp due to the presence of the superconducting current on the string leads to the different behavior of the gravitational radiation from the cusp as compa

Samvel V. Ter-Antonyan

It is shown that using the observed extensive air shower (EAS) electron and truncated muon size spectra at sea level one can solve the EAS inverse problem - reconstruction of primary energy spectra and elemental composition, for not more than 2 kinds of primary nuclei.

D. Maino, A. J. Banday, C. Baccigalupi, F. Perrotta

We present an application of the fast Independent Component Analysis method to the COBE-DMR 4yr data. Although the signal-to-noise ratio in the COBE-DMR data is typically $\sim 1$, the approach is able to extract the CMB signal with high confidence when working at high galactic latitudes. The reconstructed CMB map shows the expected frequency scaling of the

T. G. Barnes, W. H. Jefferys, J. O. Berger, P. J. Mueller

We develop and describe a Bayesian statistical analysis to solve the surface brightness equations for Cepheid distances and stellar properties. Our analysis provides a mathematically rigorous and objective solution to the problem, including immunity from Lutz-Kelker bias. We discuss the choice of priors, show the construction of the likelihood distribution,

J. G. L. Rae, N. J. B. Green, T. W. Hartquist, M. J. Pilling

A model of the grain surface chemistry involving the accretion of atoms of two different elements, X and Y, and their reactions to form species X_2, XY, and Y_2 was examined for a wide range of choices for the values of its three free parameters - the accretion rate of X and Y, the desorption rate of X and the grain surface sweeping time of Y, all considered

A. Del Popolo, S. Yesilyurt, N. Ercan

In this paper, we further develop the model for the migration of planets introduced in Del Popolo, Gambera and Ercan, and extended to time-dependent planetesimal accretion disks in Del Popolo and Eksi. More precisely, the assumption of Del Popolo and Eksi that the surface density in planetesimals is proportional to that of gas is released. Indeed, the evolut

Raffaele Gratton, Eugenio Carretta, Riccardo Claudi, Sara Lucatello

We present element-to-element abundance ratios measured from high dispersion spectra for 150 field subdwarfs and early subgiants with accurate Hipparcos parallaxes (errors <20%). For 50 stars new spectra were obtained with the UVES on Kueyen (VLT UT2), the McDonald 2.7m telescope, and SARG at TNG. Additionally, literature equivalent widths were taken from th