August 2002 arXiv papers — page 23

A. G. Doroshkevich, I. P. Naselsky, P. D. Naselsky, I. D. Novikov

The paper is devoted to the methods of determination of the cosmological parameters from recent CMB observations. We show that the more complex models of kinetics of recombination with a few "missing" parameters describing the recombination process provide better agreement between measured and expected characteristics of the CMB anisotropy. In partic

M. Matsuda, M. Fujita, K. Yamada, R. J. Birgeneau

The effects of the application of a magnetic field on the diagonal stripe spin-glass phase is studied in lightly doped La_{2-x}Sr_xCuO_4 (x=0.014 and 0.024). With increasing magnetic field, the magnetic elastic intensity at the diagonal incommensurate (DIC) positions (1,\pmε,0) decreases as opposed to the increase seen in superconducting samples. This diminu

J. Lamarcq, J. -P. Bouchaud, O. C. Martin

We study the minimum energy clusters (MEC) above the ground state for the 3-d Edwards-Anderson Ising spin glass in a magnetic field. For fields B below 0.4, we find that the field has almost no effect on the excitations that we can probe, of volume V <= 64. As found previously for B=0, their energies decrease with V, and their magnetization remains very smal

Anindya Biswas, Alok Kumar, Kamal L. Panigrahi

We present several supergravity solutions corresponding to both Dp, as well as Dp-Dp&#39; systems, in NS-NS and R-R PP-wave background originating from AdS_3 times S^3 times R^4. The Dp brane solutions, p=1,..,5 are fully localized, whereas Dp-Dp&#39; are localized along common transverse directions. We also discuss the supersymmetry properties of these solu

T. Koide, F. M. Toyama

We examine a fast decay process that arises in the transition period between the Gaussian and exponential decay processes in quantum decay systems. It is usually expected that the decay is decelerated by a confinement potential barrier. However, we find a case where the decay in the transition period is accelerated by tunneling through a confinement potentia

Holger F. Hofmann, Kunihiro Kojima, Shigeki Takeuchi, Keiji Sasaki

We show that a nonlinear phase shift of pi can be obtained by using a single two level atom in a one sided cavity with negligible losses. This result implies that the use of a one sided cavity can significantly improve the pi/18 phase shift previously observed by Turchette et al. [Phys. Rev. Lett. 75, 4710 (1995)].

Yaroslav Tserkovnyak, Arne Brataas, Gerrit E. W. Bauer

We study the magnetization dynamics in thin ferromagnetic films and small ferromagnetic particles in contact with paramagnetic conductors. A moving magnetization vector causes \textquotedblleft pumping\textquotedblright of spins into adjacent nonmagnetic layers. This spin transfer affects the magnetization dynamics similar to the Landau-Lifshitz-Gilbert phen

S. J. Akhtarshenas, M. A. Jafarizadeh

Recently in Reference [ quant-ph/0202121] a computational criterion of separability induced by greatest cross norm is proposed by Rudolph. There, Rudolph conjectured that the new criterion is not weaker than positive partial transpose criterion for separability. We show that there exist counterexample to this claim, that is, proposed criterion is weaker than

Christoph Boehme, Klaus Lips

It is shown that coherent spin motion of electron-hole pairs localized in band gap states of silicon can influence charge carrier recombination. Based on this effect, a readout concept for silicon based solid-state spin--quantum computers as proposed by Kane is suggested. The 31P quantum bit (qbit) is connected via hyperfine coupling to the spin of the local

A. B. Klimov, J. L. Romero, J. Delgado, L. L. Sanchez-Soto

We reelaborate on a general method for obtaining effective Hamiltonians that describe different nonlinear optical processes. The method exploits the existence of a nonlinear deformation of the su(2) algebra that arises as the dynamical symmetry of the original model. When some physical parameter (usually related to the dispersive limit) becomes small, we imm

G. V. Efimov, G. Ganbold

A path-integral method effective beyond the perturbation expansion approach is suggested to consider the quartic anharmonicity in different spatial dimensions. Due to an optimal representation of the partition function, the leading term has already taken into account the correct strong-coupling behaviour. In the simplest cases of zero and one dimension we ha

An Min Wang

We obtain a simplified and obvious expression of &#34;concurrence&#34; in Wootters&#39; measure of entanglement of a pair of qubits having no more than two non-zero eigenvalues in terms of concurrences of eigenstates and their simple combinations. It not only simplifies the calculation of Wootters&#39; measure of entanglement, but also reveals some its gener

M. Bienert, F. Haug, W. P. Schleich, M. G. Raizen

We propose two experimentally feasible methods based on atom interferometry to measure the quantum state of the kicked rotor.

Ph. Blanchard, R. Olkiewicz

We investigate the reduced dynamics in the Markovian approximation of an infinite quantum spin system linearly coupled to a phonon field at positive temperature. The achieved diagonalization leads to a selection of the continuous family of pointer states corresponding to a configuration space of the one-dimensional Ising model. Such a family provides a mathe

H. Bechmann-Pasquinucci, N. Gisin

Intermediate states are known from intercept/resend eavesdropping in the BB84 quantum cryptographic protocol. But they also play fundamental roles in the optimal eavesdropping strategy on BB84 and in the CHSH inequality. We generalize the intermediate states to arbitrary dimension and consider intercept/resend eavesdropping, optimal eavesdropping on the gene

Luis L. Sanchez-Soto, Julian Delgado, Andrei B. Klimov, Gunnar Bjork

We explore the role played by the phase in an accurate description of the entanglement of bipartite systems. We first present an appropriate polar decomposition that leads to a truly Hermitian operator for the phase of a single qubit. We also examine the positive operator-valued measures that can describe the qubit phase properties. When dealing with two qub

Zeqian Chen

In this note, a non-commutative analogue of the fundamental theorem of asset pricing in mathematical finance is proved.

Bruce D. Scott

Detailed computations of tokamak edge turbulence in three dimensional, globally consistent flux tube geometry show an inhibition of the standard scenario in which zonal ExB flows generated by the turbulence should lead to transport barrier formation. It is found by comparison to slab geometry and by analysis of the energetics that the zonal flow energy is de

I. M. Savukov, H. G. Berry

The ratio of two line strengths at 922.7 nm and 978.7 nm of argon is measured in an argon pulsed discharge with the use of a single-mode Ti:Sapphire laser. The result 3.29(0.13) is in agreement with our theoretical prediction 3.23 and with a less accurate ratio 2.89(0.43) from the NIST database.

M. Cosentino Lagomarsino, F. Capuani, C. P. Lowe

We describe a method, based on techniques used in molecular dynamics, for simulating the inertialess dynamics of an elastic filament immersed in a fluid. The model is used to study the &#34;one-armed swimmer&#34;. That is, a flexible appendage externally perturbed at one extremity. For small amplitude motion our simulations confirm theoretical predictions th

I. A. Stepanov

It is shown that the dependence of negative thermal expansion coefficient of many substances on the temperature contradicts to an important thermodynamic relation. It is supposed that there are oscillations at the Cp(T) and alpha(T) curves at alpha>0 and they are in reverse phases.

Dario G Perez

We introduce fractional Brownian motion processes (fBm) as an alternative model for the turbulent index of refraction. These processes allow to reconstruct most of the index properties, but they are not differentiable. We overcome the apparent impossibility of their use in the variational equation coming from the Fermat&#39;s Principle with the introduction

N. A. Mortensen, J. R. Folkenberg, P. M. W. Skovgaard, J. Broeng

We consider the problem of radiation into free space from the end-facet of a single-mode photonic crystal fiber (PCF). We calculate the numerical aperture NA=sin theta from the half-divergence angle theta ~ tan^{-1}(lambda/pi w) with pi w^2 being the effective area of the mode in the PCF. For the fiber first presented by Knight et al. we find a numerical ape

S. Hirenzaki, H. Nagahiro, T. Hatsuda, T. Kunihiro

We explore the possibility to observe an enhanced 2pi correlation in the scalar iso-scalar (sigma) channel in nuclei by (d,t) and (d,^3He) reactions to obtain new information on the partial restoration of chiral symmetry in the nuclear medium. The sensitivity of the reaction spectra on the change of the chiral condensate in the nuclear medium is examined.

D. Jido, E. Oset, A. Ramos

We perform an evaluation of the p-wave amplitudes of meson-baryon scattering in the strangeness S=-1 sector starting from the lowest order chiral Lagrangians and introducing explicitly the Sigma^* field with couplings to the meson-baryon states obtained using SU(6) symmetry. The N/D method of unitarization is used, equivalent, in practice, to the use of the

K. Chadan, N. N. Khuri, A. Martin, T. T. Wu

In this paper we study the number of bound states for potentials in one and two spatial dimensions. We first show that in addition to the well-known fact that an arbitrarily weak attractive potential has a bound state, it is easy to construct examples where weak potentials have an infinite number of bound states. These examples have potentials which decrease

A. O. L. Atkin, F. G. Garvan

New identities and congruences involving the ranks and cranks of partitions are proved. The proof depends on a new partial differential equation connecting their generating functions.

Bertram Kostant

Using the cubic Dirac operator and an extended notion of Dirac cohomology we generalize results of Huang-Pandzic, which appeared in JAMS (Sept. 6, 2001 electronic) on a conjecture of D. Vogan

Peter Schauenburg

We prove that every faithfully flat Hopf-Galois object is a quantum torsor in the sense of Grunspan.

Eric S. Egge, Toufik Mansour

Several authors have examined connections between permutations which avoid 132, continued fractions, and Chebyshev polynomials of the second kind. In this paper we prove analogues of some of these results for permutations which avoid 1243 and 2143. Using tools developed to prove these analogues, we give enumerations and generating functions for permutations

John A. Toth, Steve Zelditch

The eigenfunctions e^{i λx} of the Laplacian on a flat torus have uniformly bounded L^p norms. In this article, we prove that for every other quantum integrable Laplacian, the L^p norms of the joint eigenfunctions must blow up at a rate \gg λ^{p-2/4p - ε} for every ε>0 as λ\to \infty.

Geoffrey Grimmett, Svante Janson

Pick n points independently at random in R^2, according to a prescribed probability measure mu, and let D^n_1 <= D^n_2 <= ... be the areas of the binomial n choose 3 triangles thus formed, in non-decreasing order. If mu is absolutely continuous with respect to Lebesgue measure, then, under weak conditions, the set {n^3 D^n_i : i >= 1} converges as n --> infi

A. I. Bobenko, D. Matthes, Yu. B. Suris

A numerical scheme is developed for solution of the Goursat problem for a class of nonlinear hyperbolic systems with an arbitrary number of independent variables. Convergence results are proved for this difference scheme. These results are applied to hyperbolic systems of differential-geometric origin, like the sine-Gordon equation describing the surfaces of

Pepijn P. I. van der Laan

From the `cofree&#39; cooperad $T&#39;(A[-1])$ on a collection $A$ together with a differential, we construct an $L_\infty$-algebra structure on the total space $\bigoplus_nA(n)$ that descends to coinvariants. We use this construction to define an $L_\infty$-algebra controlling deformations of the operad $P$ under $Q$ from a cofibrant resolution for an opera

M. Fernandez-Lebron, L. Narvaez-Macarro

We show how to express any Hasse-Schmidt derivation of an algebra in terms of a finite number of them under natural hypothesis. As an application, we obtain coefficient fields of the completion of a regular local ring of positive characteristic in terms of Hasse-Schmidt derivations

Daniel S. Silver, Susan G. Williams

Torsion and Betti numbers for knots are special cases of more general invariants associated to a finitely generated group G and epimorphism from G to the integers. The sequence of Betti numbers is always periodic; under mild hypotheses, the sequence of torsion numbers satisfies a linear homogeneous recurrence relation with constant coeffiencts. Generally, th

Veronika E. Hubeny

We argue that, given the nonlocal nature of precursors in AdS/CFT correspondence, the boundary field theory contains information about events inside a black hole horizon. The essence of our proposal is sketched in figure 1, and relies on the global nature of event horizons.

L. Mesref

We show that the Woronowicz prescription using a bimodule constructed out of a tensorial product of a bimodule and its conjugate and a bi-coinvariant singlet leads to a trivial differential calculus.

Paul Koerber, Alexander Sevrin

Requiring the existence of certain BPS solutions to the equations of motion, we determine the bosonic part of the non-abelian D-brane effective action through order $α&#39;{}^4$. We also propose an economic organizational principle for the effective action.

O. F. Dayi, B. Yapiskan

Lagrangians of the Abelian Gauge Theory and its dual are related in terms of a shifted action. We show that in d=4 constrained Hamiltonian formulation of the shifted action yields Hamiltonian description of the dual theory, without referring to its Lagrangian. We apply this method, at the first order in the noncommutativity parameter theta, to the noncommuta

Umut Gursoy

We consider a BMN operator with one scalar, phi, and one vector, D_{m}Z, impurity field and compute the anomalous dimension both at planar and torus levels. This &#34;mixed&#34; operator corresponds to a string state with two creation operators which belong to different SO(4) sectors of the background. The anomalous dimension at both levels is found to be th

W. Lerche, P. Mayr, N. Warner

We study the superpotential of a certain class of N=1 supersymmetric type II compactifications with fluxes and D-branes. We show that it has an important two-dimensional meaning in terms of a chiral ring of the topologically twisted theory on the world-sheet. In the open-closed string B-model, this chiral ring is isomorphic to a certain relative cohomology g

Marcelo M. Leite

A new renormalization group treatment is proposed for the critical exponents of an m-fold Lifshitz point. The anisotropic cases (m not equal 8) are described by two independent fixed points associated to two independent momentum flow along the quadratic and quartic directions, respectively. The isotropic case is described separately. In that case, the fixed

A. Freund, A. V. Radyushkin, A. Schaefer, C. Weiss

Exclusive proton-antiproton annihilation into two photons at large s (~10 GeV^2) and |t|,|u| ~ s can be described by a generalized parton picture analogous to the &#39;soft mechanism&#39; in wide-angle real Compton scattering. The two photons are emitted in the annihilation of a single fast quark and antiquark. The matrix element describing the transition of

M. Suzuki

We explore how well one can probe the s quark chirality of the fundamental weak interaction of nonleptonic B decay using the spin-analyzing property of the Lambda hyperon. We present the prediction of the Standard Model as quantitatively as possible in a perturbative QCD picture avoiding detailed form-factor calculation involving quark mass corrections. A cl

Nikolaos Kidonakis

We present the ultraviolet poles and finite terms of two-loop vertex corrections for diagrams with massive partons in the eikonal approximation. We discover and prove that the results for a set of the corrections generalize to n-loop eikonal diagrams. These results will enhance theoretical understanding and allow greater calculational accuracy for the many p

Stanislav Dubnicka, Anna-Zuzana Dubnickova, Peter Weisenpacher

Unitary and analytic ten-resonance model of the nucleon electromagnetic (e.m.) structure with canonical normalizations and QCD (up to the logarithmic correction) asymptotics is constructed on the four-sheeted Riemann surface, which provides a superposition of vector-meson pole and continuum contributions in a very natural way. As a result it describes simult

S. Moch, J. A. M. Vermaseren

We report on the status of the calculation of deep-inelastic structure functions at three loops in perturbative QCD. The method employed allows to calculate the Mellin moments of structure functions analytically as a general function of N. As an illustration, we present the leading fermionic contributions to the non-singlet anomalous dimension of F_2 at thre

S. B. Gerasimov

The role of nonvalence, e.g., sea quarks and/or meson degrees of freedom in static electroweak baryon observables is briefly discussed.

A. Ferrari, A. Rubbia, C. Rubbia, P. Sala

We perform a systematic study of particle production and neutrino yields for different incident proton energies $E_p$ and baselines $L$, with the aim of optimizing the parameters of a neutrino beam for the investigation of $θ_{13}$-driven neutrino oscillations in the $Δm^2$ range allowed by Superkamiokande results. We study the neutrino energy spectra in the

A. K. Giri, R. Mohanta

In the presence of penguin contributions, the indirect CP asymmetry in B^0(t) --> pi^+ pi^- measures sin 2alpha_{eff}, where alpha_{eff} deviates from the true value of the CKM phase alpha by an amount theta, i.e. alpha_{eff} = alpha + theta. Using the measured value of direct CP asymmetry in B^0(t) --> pi^+ pi^-, we derive new bound on |2 theta|.

David N. Walters

We present preliminary evidence of BCS diquark condensation in the 3+1 dimensional Nambu-Jona-Lasinio (NJL) model at non-zero chemical potential (mu) on the lattice. Large N results are used to match the model&#39;s parameters to low energy, zero density phenomenology. A diquark source j is added in a partially quenched approximation to enable the measuremen

G. Andronico, A. Coniglio, S. Fortunato

In random percolation one finds that the mean field regime above the upper critical dimension can simply be explained through the coexistence of infinite percolating clusters at the critical point. Because of the mapping between percolation and critical behaviour in the Ising model, one might check whether the breakdown of hyperscaling in the Ising model can

KTeV Collaboration, A. Alavi-Harati

We present a series of measurements based on K -> pi+pi- and K -> pi0pi0 decays collected in 1996-1997 by the KTeV experiment (E832) at Fermilab. We compare these four K -> pipi decay rates to measure the direct CP violation parameter Re(e&#39;/e) = (20.7 +- 2.8) x 10^-4. We also test CPT symmetry by measuring the relative phase between the CP violating and

S. A Dytman, CLEO Collaboration

Using data collected by the CLEO detector in the Upsilon(4S) region, we report new measurements of the exclusive decays of B mesons into final states of the type Lambda_c^+ p-bar n(pi), where n=0,1,2,3. We find signals in modes with one, two and three pions and an upper limit for the two body decay Lambda_c^+ pbar. We also make the first measurements of excl

Raul Vera

In the literature, the matchings between spacetimes have been most of the times implicitly assumed to preserve some of the symmetries of the problem involved. But no definition for this kind of matching was given until recently. Loosely speaking, the matching hypersurface is restricted to be tangent to the orbits of a desired local group of symmetries admitt

C. Bona, C. Palenzuela

The gravitational radiation degrees of freedom of freedom are described in the framework of the 3+1 decomposition of spacetime. The relationship with eigenfields of the Kidder-Scheel-Teukolsky (KST) equations is established. This relationship is used to fix a parameter in the KST equations which is related to the ordering ambiguity of space derivatives in th

G. Papini, G. Scarpetta, V. Bozza, A. Feoli

The radiation emitted by charged, scalar particles in a Schwarzschild field with maximal acceleration corrections is calculated classically and in the tree approximation of quantum field theory. In both instances the particles emit radiation that has characteristics similar to those of gamma-ray bursters.

S. Bistarelli, U. Montanari, F. Rossi

Soft constraints extend classical constraints to represent multiple consistency levels, and thus provide a way to express preferences, fuzziness, and uncertainty. While there are many soft constraint solving formalisms, even distributed ones, by now there seems to be no concurrent programming framework where soft constraints can be handled. In this paper we

Kamil Kulesza, Zbigniew Kotulski

In the paper we apply graph vertex coloring for verification of secret shares. We start from showing how to convert any graph into the number and vice versa. Next, theoretical result concerning properties of n-colorable graphs is stated and proven. From this result we derive graph coloring check-digit scheme. Feasibility of proposed scheme increases with the

Aiqin Jiang, Anto Yohannan, Neme O. Nnolim, Trevor A. Tyson

The local structure of beta-tantalum was investigated by comparing experimental extended x-ray absorption fine structure (EXAFS) measurements with calculated spectra of proposed models. Four possible structure candidates were examined: a beta-Uranium based structure, a distorted A15 structure, a bcc-Ta based superlattice structure with N interstitials and a

E. Barkai

We demonstrate aging behavior in a simple non-linear system. Our model is a chaotic map which generates deterministically sub-diffusion. Asymptotic behaviors of the diffusion process are described using aging continuous time random walks, introduced previously to model diffusion in glasses.

Wiebe Geertsma

In this paper we present a study of magnetic order of quantum Heisenberg spins on pyrochlore type lattices: a lattice of corner sharing tetrahedra. We use the Cluster Variation Approximation with the tetrahedron as basic cluster. We find that in case of anti-ferromagnetic nearest--neighbour exchange there is no long--range spin order at any finite temperatur

Nicola Scafetta, Tim Imholt, Paolo Grigolini, Jim Roberts

This paper presents a global air and sea temperature anomalies analysis based upon a combination of the wavelet multiresolution analysis and the scaling analysis methods of a time series. The wavelet multiresolution analysis decomposes the two temperature signals on a scale-by-scale basis. The scale-by-scale smooth and detail curves are compared and the corr

I. P. Raevski, S. A. Prosandeev, U. Waghmare, V. V. Eremkin

Experimental data obtained for PbFe$_{1 / 2}$Ta$_{1 / 2}$O$_{3}$ (PFT) and NaNbO$_{3}$: Gd (NaNbGd) single crystals show a diffused dielectric permittivity peak that is inherent to relaxor ferroelectrics. However some deviations from the normal relaxor properties were also observed and are under discussion. One of the key features of the relaxors is the exis

C. Pfleiderer, A. D. Huxley

The recent discovery that superconductivity occurs in several clean itinerant ferromagnets close to low temperature magnetic instabilities naturally invites an interpretation based on a proximity to quantum criticality. Here we report measurements of the pressure dependence of the low temperature magnetisation in one of these materials, UGe_2. Our results sh

Xiao-Qian Wang

The mapping between the metal-insulator transition of the quantum Hall system and a superfluid-to-insulator transition is revisited based on a disordered anyon model. The one-parameter scaling of the superfluid-to-insulator transition is employed for the analysis of the scaling behavior of the integer quantum Hall transitions. The analysis reveals the direct

W. Geertsma, D. Gonzalez, L. H. Gonzalez

We study the electronic properties (density of states, conductivity and thermopower) of some nearly--free--electron systems: the liquid alkali metals and two liquid alloys, Li-Na and Na-K. The study has been performed within the self-consistent second order Renormalized Propagator Perturbation Expansion (RPE) for the self-energy. The input ionic pseudopotent

Jie Han

An integrating theoretical scenario of superconductivity and superfluidity has been built. It reduces to the special BCS superconductivity mechanism for conventional superconductor and to a new theory for high transition temperature superconductors, which can explain the recent angle-resolved photoemission experiments and the earlier nuclear spin-lattice rel

O. Sirjean, S. Seidelin, J. Viana Gomes, D. Boiron

We have studied ionizing collisions in a BEC of He*. Measurements of the ion production rate combined with measurements of the density and number of atoms for the same sample allow us to estimate both the 2 and 3-body contributions to this rate. A comparison with the decay of the number of condensed atoms in our magnetic trap, in the presence of an rf-shield

C. Gros, P. Lemmens, K. -Y. Choi, G. G&#34;untherodt

The study of quantum phase transitions, which are zero-temperature phase transitions between distinct states of matter, is of current interest in research since it allows for a description of low-temperature properties based on universal relations. Here we show that the crystal green dioptase Cu_6Si_6O_18 . 6H_2O, known to the ancient Roman as the gem of Ven

Takashi Yanagisawa, Soh Koike, Kunihiko Yamaji

The ground state of the two-dimensional three-band Hubbard model in oxide superconductors is investigated by using the variational Monte Carlo method. The Gutzwiller-projected BCS and spin- density wave (SDW) functions are employed in the search for a possible ground state with respect to dependences on electron density. Antiferromagnetic correlations are co

J. Dzubiella, H. Loewen

The influence of an external field acting differently on the two constituents of a binary colloidal mixture performing Brownian dynamics is investigated by computer simulations and a simple theory. In our model, one half of the particles ($A$-particles) are pulled by an external force ${\vec F}^{(A)}$ while the other half of them ($B$-particles) are pulled b

J. Dzubiella, A. G. Moreira, P. A. Pincus

We theoretically study the polarizability and the interactions of neutral complexes consisting of a semi-flexible polyelectrolyte adsorbed onto an oppositely charged spherical colloid. In the systems we studied, the bending energy of the chain is small compared to the Coulomb energy and the chains are always adsorbed on the colloid. We observe that the polar

Sang Wook Kim

A Floquet scattering approach to parametric electron pumps is presented and compared with Brouwer&#39;s adiabatic scattering approach [Phys. Rev. B 58, R10135 (1998)] for a simple scattering model with two harmonically oscillating delta-function barriers. For small strength of oscillating potentials these two approaches give exactly equivalent results while

Baowen Li, Giulio Casati, Jiao Wang

We present analytical and numerical results on the heat conduction in a linear mixing system. In particular we consider a quasi one dimensional channel with triangular scatterers with internal angles irrational multiples of pi and we show that the system obeys Fourier law of heat conduction. Therefore deterministic diffusion and normal heat transport which a

Paolo Politi, Maria Gloria Pini

We determine the effective dipolar interaction between single domain two-dimensional ferromagnetic particles (islands or dots), taking into account their finite size. The first correction term decays as 1/D^5, where D is the distance between particles. If the particles are arranged in a regular two-dimensional array and are magnetized in plane, we show that

Yoichi Ando, Kouji Segawa, A. N. Lavrov, Seiki Komiya

Behavior of ρ_{ab}(T) and R_{H}(T) is presented for LSCO and YBCO single crystals in the lightly hole-doped antiferromagnetic region, with an emphasis on the R_{H}(T) data. In both systems, R_{H} is virtually constant at moderate temperatures and tends to increase at low temperatures. Since essentially the same behavior of ρ_{ab}(T) and R_{H}(T) is observed

Denis Bartolo, Armand Ajdari, Jean-Baptiste Fournier, Ramin Golestanian

The force experienced by objects embedded in a correlated medium undergoing thermal fluctuations--the so-called fluctuation--induced force--is actually itself a fluctuating quantity. We compute the corresponding probability distribution and show that it is a Gaussian centered on the well-known Casimir force, with a non-universal standard deviation that can b

W. Sakikawa, O. Narikiyo

We have shown that the epsilon-entropy determined from the time-series of the velocity fluctuation in a forced turbulence simulated by the lattice Boltzmann method obeys the Kolmogorov scaling.

Yong-Hoon Kim, Andreas Goerling

Applying the novel exact-exchange (EXX) Kohn-Sham method within time-dependent density-functional theory, we obtained the optical absorption spectrum of bulk silicon in good agreement with experiments including excitonic features. Analysis of the EXX kernel shows that inclusion of the Coulomb coupling of electron-hole pairs and the correct long-wavelength be

G. L. Buchbinder

The mass transfer of interstitial impurities in a crystalline lattice under the influence of the fast-moving deformation disturbance of the type of a shock wave is considered. The velocity of the movement of the disturbance is supposed to be compared with the characteristic velocity of the relaxation of the diffusion flux to its local equilibrium value deter

John Cardy, Robert Ziff

At the critical point in two dimensions, the number of percolation clusters of enclosed area greater than A is proportional to 1/A, with a proportionality constant C that is universal. We show theoretically (based upon Coulomb gas methods), and verify numerically to high precision, that C = 1/(8 sqrt(3) pi) = 0.022972037.... We also derive, and verify to var

M. Samsel-Czekala, G. Kontrym-Sznajd, G. Doring, W. Schulke

A reconstruction technique based on Radon transforms is used to obtain 3D electron momentum density rho(p) using nine recently measured high-resolution Compton profiles (CPs) from a Cu_{0.9}Al_{0.1} disordered alloy single crystal. The method was also applied to nine corresponding theoretical CPs computed within the KKR-CPA first-principles scheme in order t

M. Biasini, A. Czopnik, A. Jura, G. Kontrym-Sznajd

For a single crystal of TmGa3, two-dimensional angular correlation of positron annihilation radiation spectra were measured and subjected to a deconvolution algorithm based on the Van Citter iterative method. The three-dimensional electron-positron momentum density was reconstructed both via the Cormack and a modified Fourier-transform-based method. After th

G. Kontrym-Sznajd, H. Sormann, R. N. West

Electron-positron momentum densities in Y, reconstructed from two-dimensional angular correlation of annihilation radiation spectra, are compared with the theoretical predictions of fully-relativistic augmented plane-wave calculations. Knowledge of the theoretical densities and of the effects on them of certain symmetry selection rules has allowed us to sepa

Jason X. Prochaska

Observations of the Galactic ISM have had tremendous impact on our understanding of the physics of galactic gas and the processes of galaxy formation. Similar observations at z>2 reveal the neutral baryonic content of the universe, trace the evolution of metal enrichment, shed light on process of nucleosynthesis and dust formation, and yield precise measurem

J. -H. Woo, C. Gallart, P. Demarque, S. Yi

We present an analysis of CMDs of three intermediate-age LMC clusters, namely NGC 2173, SL 556 and NGC 2155. The main goal of our project is to investigate the amount of convective core overshoot necessary to reproduce the CMDs of relatively metal-poor, intermediate age stellar populations. We conclude that a moderate amount of overshoot and some fraction of

Pimol Moth, Richard J. Elston

We fit elliptical isophotes to the Hubble Deep Field-North WFPC-2 and NICMOS data to study the rest-frame UV_{218}-U_{300} color profiles and rest-frame B surface brightness profiles of 33 intermediate redshift galaxies (0.5 <= z <= 1.2) with I_{814} < 25 and 50 high redshift galaxies (2.0 <= z <= 3.5) with H_{160}< 27. From the weighted least-squares fit to

B. D. Savage, K. R. Sembach, B. P. Wakker, P. Richter

FUSE spectra of 100 extragalactic objects are analyzed to obtain measures of O VI absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the approximate velocity range from -100 to 100 km/s reveals a widespread but highly irregular distribution of thick disk O VI, implying the existence of substantial amounts of hot gas wit

Jorick S. Vink, Janet E. Drew, Tim J. Harries, Rene D. Oudmaijer

We present Halpha spectropolarimetry observations of a sample of 23 Herbig Ae/Be stars. A change in the linear polarisation across Halpha is detected in a large fraction of the objects, which indicates that the regions around Herbig stars are flattened (disc-like) on small scales. A second outcome of our study is that the spectropolarimetric signatures for t

Barbara Pichardo, Marco Martos, Edmundo Moreno, Julia Espresate

With the aim of studying the nonlinear stellar and gaseous response to the gravitational potential of a galaxy such as the Milky Way, we have modeled 3D galactic spiral arms as a superposition of inhomogeneous oblate spheroids and added their contribution to an axisymmetric model of the Galactic mass distribution. Three spiral loci are proposed here, based i

S. Frittelli, A. O. Petters

Very little attention has been paid to the properties of optical wavefronts and caustic surfaces due to gravitational lensing. Yet the wavefront-based point of view is natural and provides insights into the nature of the caustic surfaces on a gravitationally lensed lightcone. We derive analytically the basic equations governing the wavefronts, lightcones, ca

A. Grazian, A. Omizzolo, C. Corbally, S. Cristiani

This is the second paper of a series describing the Asiago-ESO/RASS QSO survey, a project aimed at the construction of an all-sky statistically well-defined sample of very bright QSOs (B_J < 15). Such a survey is required to remove the present uncertainties about the properties of the local QSO population and constitutes an homogeneous database for detailed

Gijs Verdoes Kleijn, Roeland van der Marel, Tim de Zeeuw, Jacob Noel-Storr

(abridged) We investigate the kinematics of the central gas disk of the radio-loud elliptical galaxy NGC 4335, derived from HST/STIS long-slit spectroscopic observations of Halpha+[NII] along 3 parallel slit positions. The observed mean velocities are consistent with a rotating thin disk. We model the gas disk in the customary way. This sets a 3 sigma upper

A. P. Colombo, T. Belloni, J. Homan, S. Campana

We present results of spectral and timing analysis based on 11 RXTE PCA/HEXTE observations of the microquasar XTE J1550-564 during its last outburst in January 2002. The observed behaviour is comparable to most Black-Hole Candidates in the low/hard state. This is unlike the 1998-99 outburst, when it showed a much more complex feature, probably because of the

T. Belloni, E. Nespoli, J. Homan, M. van der Klis

We report preliminary results of a RossiXTE campaign on the 2002 outburst of the black-hole candidate GX 339-4. We show power density spectra of five observations during the early phase of the outburst. The first four power spectra show a smooth transition between a Low State and a Very High State. The fifth power spectrum resembles a High State, but a stron

Tomaso Belloni

It is now ten years since the first microquasar GRS 1915+105 was discovered. More than six years of observations with RossiXTE have shown a level of variability never observed in any other X-ray source. Here I try to address some issues, based on X-ray observations only, that have relevance for theoretical modeling. First, I ignore these peculiarities and co

Z. Paragi, I. Fejes, R. C. Vermeulen, R. T. Schilizzi

We summarize the results of VLBA and global VLBI observations of SS433 between 1995 and 2000. With these observations we resolve the inner jet of the source and identify an absorption region (~25 AU), the &#34;central radio gap&#34;. The radio gap is caused by free-free absorption of the jet radio emission by a flattened outflow from the binary system. Radio

A. V. Zasov, D. V. Bizyaev, D. I. Makarov, N. V. Tyurina

We consider a thickness of stellar disks of late-type galaxies by analyzing the R and K_s band photometric profiles for two independent samples of edge-on galaxies. The main goal is to verify a hypotesis that a thickness of old stellar disks is related to the relative masses of the spherical and disk components of galaxies. We confirm that the radial-to-vert