July 2002 arXiv papers — page 13

Takashi Uchihashi, Urs Ramsperger

We measure the electron conductivity of the surface states and the subsurface space charge layer originating from the Si(111)-4x1-In reconstruction as a function of temperature. The conductivity of the surface states drops sharply around 130 K with decreasing temperature, revealing a metal-insulator phase transition of the surface reconstruction. In contrast

Baigeng Wang, Jian Wang

We investigate the parametric pumping of a hybrid structure consisting of a normal quantum dot, a normal lead and a superconducting lead. Using the time dependent scattering matrix theory, we have derived a general expression for the pumped electric current and heat current. We have also derived the relationship among the instantaneous pumped heat current, e

Giorgio Parisi

In this talk I will introduces two spaces: the first space is the usual n-dimensional vector space with the unusual feature that n is non-integer, the second space is composed by the linear matrices acting on the previous space (physicists are particularly interested to study the limit n going to zero). These two spaces are not known to most of the mathemati

K. Sato, K. Sekimoto, T. Hondou, F. Takagi

When a small dynamical system that is initially in contact with a heat bath is detached from this heat bath and then caused to undergo a quasi-static adiabatic processes, the statistical distribution of the system's energy differs from that of an equilibrium ensemble. Subsequent contact of the system with another heat bath is inevitably irreversible, hen

B. T. Soifer, G. Neugebauer, K. Matthews, E. Egami

Low spectral resolution (delta lambda/lambda ~ 50) mid-infrared observations with high angular resolution (0.3--0.5'') using the Long Wavelength Spectrometer on the Keck I Telescope are reported of the nuclei of five highly luminous infrared bright galaxies. Spectra of eight distinct nuclei, ranging in luminosity from 10^11 L_sun to >10^12 L_sun have

Yoel Rephaeli, Duane Gruber

The RXTE satellite observed the Coma cluster for 177 ksec during November and December 2000, a second observation motivated by the intriguing results from the first 87 ksec observation in 1996. Analysis of the new dataset confirms that thermal emission from isothermal gas does not provide a good fit to the spectral distribution of the emission from the inner

L. L. Kiss, A. Derekas, E. J. Alfaro, I. B. Biro

We present an analysis of new Johnson and Stromgren photometric and medium-resolution spectroscopic observations of the delta Scuti type variable star V784 Cassiopeae. The data were obtained in three consecutive years between 1999 and 2001. The period analysis of the light curve resulted in the detection of four frequencies ranging from 9.15 c/d to 15.90 c/d

A. D. Dolgov

Different scenarios of baryogenesis are briefly reviewed from the point of view of possibility of generation of cosmologically interesting amount of antimatter. It is argued that creation of antimatter is possible and natural in many models. In some models not only anti-helium may be produced but also a heavier anti-elements and future observations of the la

E. Costa, P. Soffitta, G. Di Persio, M. Feroci

X-ray Polarimetry is almost as old as X-ray Astronomy. Since the first discovery of X-ray sources theoretical analysis suggested that a high degree of linear polarization could be expected due either to the, extremely non thermal, emission mechanism or to the transfer of radiation in highly asymmetric systems. The actual implementation of this subtopic was,

R. Baptista, F. Jablonski, E. Oliveira, S. Vrielmann

We report the identification of cyclical changes in the orbital period of the eclipsing dwarf nova Z Cha. We used times of mid-eclipse collected from the literature and our new eclipse timings to construct an observed-minus-calculated diagram covering 30 years of observations (1972-2002). The data present cyclical variations that can be fitted by a linear pl

S. Shibata, M. Tomatsuri, M. Shimanuki, K. Saito

This paper deals with the Crab Nebula problem to suggest that particle acceleration takes place not only at the inner shock but also over a larger region in the nebula with disordered magnetic field. Kennel and Cornoniti (1984) constructed a spherically symmetric model of the Crab Nebula and concluded that the pulsar wind which excites the nebular is kinetic

Weiqun Zhang, S. E. Woosley, A. I. MacFadyen

We examine the propagation of 2-dimensional relativistic jets through the stellar progenitor in the collapsar model for gamma-ray bursts. In agreement with previous studies, we find that relativistic jets are collimated by their passage through the stellar mantle. Interaction of these jets with the star and their own cocoons also causes mixing that sporadica

Michiyasu Nagasawa, Robert Brandenberger

The standard electroweak theory admits a string solution, the Z string, in which only the electrically neutral Higgs fields are excited. This solution is unstable at zero temperature: Z strings decay by exciting charged Higgs modes. In the early Universe, however, there was a long period during which the Higgs particles were out of equilibrium but the photon

Veit Elser

Iterative phase retrieval algorithms typically employ projections onto constraint subspaces to recover the unknown phases in the Fourier transform of an image, or, in the case of x-ray crystallography, the electron density of a molecule. For a general class of algorithms, where the basic iteration is specified by the difference map, solutions are associated

Jeff McIntire

Bound, strange, neutral superheavy nuclei, stable against strong decay, may exist. A model effective field theory calculation of the surface energy and density of such systems is carried out assuming vector meson couplings to conserved currents and scalar couplings fit to data where it exists. The non-linear relativistic mean field equations are solved assum

Sudarshan Fernando, Murat Gunaydin, Oleksandr Pavlyk

In this paper we show how one can obtain very simply the spectra of the PP-wave limits of M-theory over AdS_7(4) x S^4(7) spaces and IIB superstring theory over AdS_5 x S^5 from the oscillator construction of the Kaluza-Klein spectra of these theories over the corresponding spaces. The PP-wave symmetry superalgebras are obtained by taking the number P of ``c

A. DeBenedictis, A. Das

This paper studies wormhole solutions to Einstein gravity with an arbitrary number of time dependent compact dimensions and a matter-vacuum boundary. A new gauge is utilized which is particularly suited for studies of the wormhole throat. The solutions possess arbitrary functions which allow for the description of infinitely many wormhole systems of this typ

Andrew M. Steane

Fault tolerant quantum error correction (QEC) networks are studied by a combination of numerical and approximate analytical treatments. The probability of failure of the recovery operation is calculated for a variety of CSS codes, including large block codes and concatenated codes. Recent insights into the syndrome extraction process, which render the whole

Johannes Huebschmann

Exploiting a notion of Kaehler structure on a stratified space introduced elsewhere we show that, in the Kaehler case, reduction after quantization coincides with quantization after reduction: Key tools developed for that purpose are stratified polarizations and stratified prequantum modules, the latter generalizing prequantum bundles. These notions encapsul

S. Scheel, J. Eisert, P. L. Knight, M. B. Plenio

How mixed can one component of a bi-partite system be initially and still become entangled through interaction with a thermalized partner? We address this question here. In particular, we consider the question of how mixed a two-level system and a field mode may be such that free entanglement arises in the course of the time evolution according to a Jaynes-C

Takao Morinari

We investigate effects of doped holes' hopping on Neel order in the two-dimensional Hubbard model. Semiclassical staggered moments are computed by solving saddle point equations derived from a path-integral formalism. Effects of quantum fluctuations are taken into account by the Schwinger boson mean field theory. We argue that hopping of doped holes is i

R. Jeannerot, S. Khalil, G. Lazarides

A new shifted hybrid inflationary scenario is introduced which, in contrast to the older one, relies only on renormalizable superpotential terms. This scenario is automatically realized in a concrete extension of the "minimal" supersymmetric Pati-Salam model which naturally leads to a moderate violation of Yukawa unification so that, for mu>0, the pr

Seher Ozcelik, Ayse Erzan

We propose and solve a Hamiltonian model for multidimensional epistastatic interactions between beneficial mutations. The model is able to give rise either to a phase transition between two equilibrium states, without any coexistence, or exhibits a state where hybrid species can coexist, with gradual passage from one wild type to another. The transition take

Tarun Kanti Ghosh, G. Baskaran

Cooperative ring-exchange is suggested as a mechanism of quantum melting of vortex lattices in a rapidly-rotating quasi two dimensional atomic Bose-Einstein condensate (BEC). Using an approach pioneered by Kivelson et al. [Phys. Rev. Lett. {\bf 56}, 873 (1986)] for the fractional quantized Hall effect, we calculate the condition for quantum melting instabili

C. Sliwa, K. Banaszek

A simple experimental setup consisting of a spontaneous parametric down-conversion source and passive linear optics is proposed for conditional preparation of a maximally entangled polarization state of two photons. Successful preparation is unambiguously heralded by coincident detection of four auxiliary photons. The proposed scheme utilizes the down-conver

V. Vedral

We analyze a quantum measurement where the apparatus is initially in a mixed state. We show that the amount of information gained in a measurement is not equal to the amount of entanglement between the system and the apparatus, but is instead equal to the degree of classical correlations between the two. As a consequence, we derive an uncertainty-like expres

Bojana Korin-Hamzic, Emil Tafra, Mario Basletic, Amir Hamzic

We investigated the transport properties of the quasi one-dimensional organic metal (TMTSF)2ReO4 above the anion-ordering metal-insulator transition (T_{AO} \approx 180K). The pronounced conductivity anisotropy, a small and smoothly temperature dependent Hall effect, and a small, positive and temperature dependent magnetoresistance are analyzed within the ex

A. J. Buras, P. H. Chankowski, J. Rosiek, L Slawianowska

Considering the MSSM with the CKM matrix as the only source of flavour violation and heavy supersymmetric particles at large $\tanβ$, we analyze the correlation between {\it the increase} of the rates of the decays $B^0_{s,d}\to μ^+μ^-$ and {\it the suppression} of $ΔM_s$, that are caused by the enhanced flavour changing neutral Higgs couplings to down-type

Stephen Godfrey, Pat Kalyniak, Nikolai Romanenko

We study the discovery limits for doubly charged Higgs bosons, Delta^{--}, obtainable at the LEP e^+e^- collider. We expect that the LEP2 collaborations can rule out the existence of a doubly charged Higgs boson of mass below about 190 GeV for Yukawa couplings greater than 0.1. However, even for larger values of M_Delta, evidence for the Delta can be seen du

Nicola Rossano Bruno

I examine the structure of the deformed Lorentz transformations in one of the recently-proposed schemes with two observer-independent scales. I develop a technique for the analysis of general combinations of rotations and deformed boosts. In particular, I verify explicitly that the transformations form group.

Apostolos Dimitriadis, Simon F. Ross

We consider the stability of the two branches of non-extremal enhancon solutions. We argue that one would expect a transition between the two branches at some value of the non-extremality, which should manifest itself in some instability. We study small perturbations of these solutions, constructing a sufficiently general ansatz for linearised perturbations

Andreas Bredthauer

We investigate the set of boundary states in the symplectic fermion description of the logarithmic conformal field theory with central charge c=-2. We show that the thus constructed states correspond exactly to those derived under the restrictions of the maximal chiral symmetry algebra for this model, W(2,3,3,3). This connects our previous work to the cohere

G. E. Bruno

The NA57 experiment has been designed to study the onset of enhanced production of strange baryons and anti-baryons in Pb-Pb collisions with respect to p-Be collisions. This enhancement is considered a sensitive signature for a phase transition to a new state of matter -- the Quark Gluon Plasma (QGP). In this paper, we report results on Lambda and Xi hyperon

Hiroshi Ishikawa, Taro Tani

We develop a systematic method to solve the Cardy condition for the coset conformal field theory G/H. The problem is equivalent to finding a non-negative integer valued matrix representation (NIM-rep) of the fusion algebra. Based on the relation of the G/H theory with the tensor product theory G x H, we give a map from NIM-reps of G x H to those of G/H. Our

Peter Holdsworth, Mauro Sellitto

The vortex contribution to the probability density function of longitudinal magnetization fluctuations is examined in finite 2D XY systems close to the Kosterlitz-Thouless-Berezinskii transition temperature. Within the temperature range studied their relevance is limited to rare fluctuations, where they increase the probability of events exceeding four stand

Bernhard G. Bodmann

We investigate a class of operators resulting from a quantization scheme attributed to Berezin. These so-called Berezin-Toeplitz operators are defined on a Hilbert space of square-integrable holomorphic sections in a line bundle over the classical phase space. As a first goal we develop self-adjointness criteria for Berezin-Toeplitz operators defined via qua

Raul Rabadan, Frederic Zamora

We analyse some physical consequences when supersymmetry is broken by a set of D-branes and/or orientifold planes in Type II string theories. Generically, there are global dilaton tadpoles at the disk level when the transverse space is compact. By taking the toy model of a set of electric charges in a compact space, we discuss two different effects appearing

S. A. E. G. Falle

We show that there are simple one dimensional problems for which the MHD code, ZEUS, generates significant errors, whereas upwind conservative schemes perform very well on these problems.

Manfred Lindner, Tommy Ohlsson, Ricard Tomas, Walter Winter

We investigate the possibility to use the neutrinos coming from a future galactic supernova explosion to perform neutrino oscillation tomography of the Earth's core. We propose to use existing or planned detectors, resulting in an additional payoff. Provided that all of the discussed uncertainties can be reduced as expected, we find that the average matt

Markus Eidemuller

In this work the charm and bottom quark masses are determined from QCD moment sum rules for the charmonium and upsilon systems. To illustrate the special character of these sum rules when applied to Coulomb systems we first set up and study the behaviour of the sum rules in quantum mechanics. In our analysis we include both the results from nonrelativistic Q

G. S. Agarwal, P. K. Pathak, M. O. Scully

Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two Ramsey zones have precise number of photons. However in this case we show how two atom (like two photon) interferometry can be used to discern a variety of interferen

G. Mukherjee, S. S. Manna

A network is formed using the $N$ sites of an one-dimensional lattice in the shape of a ring as nodes and each node with the initial degree $k_{in}=2$. $N$ links are then introduced to this network, each link starts from a distinct node, the other end being connected to any other node with degree $k$ randomly selected with an attachment probability proportio

M. N. Rebelo

In this letter we give a class of examples where the decays of the heavy Majorana neutrinos may violate CP even if there is no CP violation at low energies, i.e., leptogenesis can take place without Majorana or Dirac type CP phases at low energies.

D. Belitz, T. R. Kirkpatrick

The quantum phase transition in clean itinerant ferromagnets is analyzed. It is shown that soft particle-hole modes invalidate Hertz&#39;s mean-field theory for $d \leq 3$. A renormalized mean-field theory predicts a fluctuation-induced first order transition for $1 < d \leq 3$, whose stability is analyzed by renormalization group techniques. Depending on mi

D. P. Caetano, M. P. Almeida, P. H. Souto Ribeiro, A. Z. Khoury

We study theoretical and experimentally the propagation of the angular spectrum of the light produced in the up-conversion process. The connection between the angular spectrum of the fundamental and the second harmonic is derived and measured. We show that even though they are connected, it is not possible to directly transfer images from the fundamental to

Masanao Ozawa

The Heisenberg uncertainty principle states that the product of the noise in a position measurement and the momentum disturbance caused by that measurement should be no less than the limit set by Planck&#39;s constant, hbar/2, as demonstrated by Heisenberg&#39;s thought experiment using a gamma-ray microscope. Here I show that this common assumption is false

N. David Mermin

A strategy is suggested for teaching mathematically literate students, with no background in physics, just enough quantum mechanics for them to understand and develop algorithms in quantum computation and quantum information theory. Although the article as a whole addresses teachers of physics, well versed in quantum mechanics, the central pedagogical develo

Jean-Michel Gerard, Bruno Gayral, Emmanuel Moreau

We discuss the efficiency of single photon sources based on a single quasi-monochromatic emitter (such as a semiconductor quantum dot) inserted in a pillar microcavity. We show that their efficiency, which is in principle excellent thanks to the Purcell effect, can be drastically limited by extrinsic cavity losses, such as those related to the scattering by

Stefan Scheel, Dirk-Gunnar Welsch

In this article we review properties of Gaussian states and describe operations on them. The interaction of the electromagnetic field with an absorbing dielectric as a special type of environmental interaction will serve as the basis for the understanding of decoherence and entanglement degradation of Gaussian states of light propagating through fibers. The

Andrzej Grudka, Antoni Wojcik

We will present a method of implementation of general projective measurement of two-photon polarization state with the use of linear optics elements only. The scheme presented succeeds with a probability of at least 1/16. For some specific measurements, (e.g. parity measurement) this probability reaches 1/4.

Rachel E. Scherr, Peter S. Shaffer, Stamatis Vokos

Previous research indicates that after standard instruction students at all academic levels often construct a conceptual framework in which the ideas of absolute simultaneity and the relativity of simultaneity co-exist. This article describes the development and assessment of instructional materials intended to improve student understanding of the concept of

Rachel E. Scherr, Michael C. Wittmann

Even in the relatively favorable circumstances of an individual interview, accurate listening requires careful effort. Our research interests dictate which student statements we attend to during the interview, and which we consider to constitute data during later analysis. Explicit consideration of possible research agendas can increase opportunity for produ

Roman G. Vorobyov

It is shown, that the space quantum existence (SQE)non-ambigously determine the metric form for the space without time, using weak condition of metrics addivity. The hypotesis is proposed, Riemann metics is only possible for quantized space classes. This statement probably can close the problem of metrics form.

S. Schramm

We investigate the deformation properties of atomic nuclei in a hadronic chiral SU_f(3) model approach. The parameters are fitted to hadron mass properties and adjustments for spherical finite nuclei have been performed. Using these parameters the deformation of a series of light and heavy nuclei are obtained in a two-dimensional self-consistent calculation.

O. Bartalini, V. Bellini, J. -P. Bocquet, M. Capogni

The Sigma beam asymmetry for positive pion photoproduction on the proton has been measured over an angular range of 40-170 deg at photon energies from 0.8 to 1.5 GeV. The resulting data set includes 237 accurate points, 136 of these belonging to an almost unexplored domain above 1.05 GeV. Data of such high precision provide severe constraints for partial wav

Valerii S. Dryuma, Maxim Pavlov

We consider the properties of the second order nonlinear differential equations b&#39;&#39;= g(a,b,b&#39;) with the function g(a,b,b&#39;=c) satisfying the following nonlinear partial differential equation $$ \frac{d^2 g_{cc}}{da^2}-g_{c}\frac{dg_{cc}}{da}-4\frac{dg_{bc}}{da}+ $$ $$ +4g_{c}g_{bc}-3g_{b}g_{cc}+6g_{bb}=0, $$ where: $$ \frac{d}{da}=\frac{\parti

Michel Van den Bergh

If Y,Z are three-dimensional smooth varieties related by a flop, then Bondal and Orlov conjectured that the derived categories of coherent sheaves on Y and Z are equivalent. This conjecture was recently proved by Bridgeland. Our aim in this paper is to give a partially new proof of Bridgeland&#39;s result using non-commutative rings. The new proof also cover

Greg W. Anderson, W. Dale Brownawell, Matthew A. Papanikolas

We devise a new criterion for linear independence over function fields. Using this tool in the setting of dual t-motives, we find that all algebraic relations among special values of the geometric function field Gamma-function are explained by the standard functional equations.

Constantin M. Petridi, Peter B. Krikelis

We reduce the principal problem of Additive Number Theory of whether an infinite sequence of integers constitutes a finite basis for the integers to a Diophantine problem involving the difference set of the sequence, by proving a formula connecting the respective number of solutions.

Giulianella Coletti, Romano Scozzafava, Barbara Vantaggi

In this talk - based on the results of a forthcoming paper (Coletti, Scozzafava and Vantaggi 2002), presented also by one of us at the Conference on &#34;Non Classical Logic, Approximate Reasoning and Soft-Computing&#34; (Anacapri, Italy, 2001) - we discuss the problem of representing default rules by means of a suitable coherent conditional probability, def

Eberhard Kirchberg, Wilhelm Winter

We introduce the decomposition rank, a notion of covering dimension for nuclear C^*-algebras. The decomposition rank generalizes ordinary covering dimension and has nice permanence properties; in particular, it behaves well with respect to direct sums, quotients, inductive limits, unitization and quasidiagonal extensions. Moreover, it passes to hereditary su

J. Denef, F. Loeser

We survey our recent work on an extension of the theory of motivic integration, called arithmetic motivic integration. We developed this theory to understand how p-adic integrals of a very general type depend on p.

Nikolai Neumaier, Stefan Waldmann

In this paper, the notion of star products with separation of variables on a Kahler manifold is extended to bimodule deformations of (anti-) holomorphic vector bundles over a Kahler manifold. Here the Fedosov construction is appropriately adapted using the geometric data of a connection in the vector bundle. Moreover, the relation between the star products o

Rob Kusner

Let M = M_{g,k} denote the space of properly (Alexandrov) embedded constant mean curvature (CMC) surfaces of genus g with k (labeled) ends, modulo rigid motions, endowed with the real analytic structure described in [kmp]. Let $P = P_{g,k} = r_{g,k} \times R_+^k$ be the space of parabolic structures over Riemann surfaces of genus g with k (marked) punctures,

S Addas-Zanata

We investigate the break up of the last invariant curve for families of standard maps. Our main result is another evidence of how hard this problem is. We give an example of an analytic mapping with a &#34;pathological&#34; behavior, related to the break up of the last rotational invariant curve.

Jun-ichi Miyachi

First, we study recollement of a derived category of unbounded complexes of modules induced by a partial tilting complex. Second, we give equivalent conditions for P^{centerdot} to be a recollement tilting complex, that is, a tilting complex which induces an equivalence between recollements $\{\cat{D}_{A/AeA}(A), \cat{D}(A), \cat{D}(eAe)}$ and $\{\cat{D}_{B/

James M. Cline, Jérémie Vinet

We present the results of work in which we derived the order rho^2 corrections to the Friedmann equations in the Randall-Sundrum I model. The effects of Golberger-Wise stabilization are taken into account. We surprisingly find that in the cases of inflation and radiation domination, the leading corrections on a given brane come exclusively from the effects o

L. Baulieu

Group theory indicates the existence of a $SO(8) X SO(7) \subset SO(16)$ invariant self-duality equation for a 3-form in 16 dimensions. It is a signal for interesting topological field theories, especially on 8-dimensional manifolds with holonomy group smaller than or equal to Spin(7), with a gauge symmetry that is SO(8) or SO(7). Dimensional reduction also

Cezary Gonera

Recently proposed procedure of constructing maximally superintegrable systems of Winternitz type is further developed and illustrated by an example of system admitting an explicit construction of angle variables and additional integrals of motion. A possible application of the method to Liouville system is briefly presented.

D. H. Correa, E. F. Moreno, F. A. Schaposnik

We construct U(2) noncommutative multi-instanton solutions by extending Witten&#39;s ansatz [1] which reduces the problem of cylindrical symmetry in four dimensions to that of a set of Bogomol&#39;nyi equations for an Abelian Higgsmodel in two dimensional curved space. Using the Fock space approach, we give explicit vortex solutions to the Bogomol&#39;nyi eq

Gerard &#39;t Hooft

A Procedure is outlined that may be used as a starting point for a perturbative treatment of theories with permanent confinement. By using a counter term in the Lagrangian that renormalizes the infrared divergence in the Coulomb potential, it is achieved that the perturbation expansion at a finite value of the strong coupling constant may yield reasonably ac

Paul Fendley, Nicholas Read

We study the algebraic formulation of exact factorizable S-matrices for integrable two-dimensional field theories. We show that different formulations of the S-matrices for the Potts field theory are essentially equivalent, in the sense that they can be expressed in the same way as elements of the Temperley-Lieb algebra, in various representations. This enab

Debajyoti Choudhury, Rohini M. Godbole, Giacomo Polesello

We revisit the issue of probing R-violating couplings of supersymmetric theories at hadronic colliders, particularly at the LHC. Concentrating on dimuon production, an evaluation of the optimal sensitivity to the R-violating coupling is performed through a maximum likelihood analysis. The measurement uncertainties are evaluated through a study of fully gener

Debajyoti Choudhury, Swapan Majhi, V. Ravindran

We consider resonant production of sneutrino and slepton at hadronic colliders such as the Tevatron and the LHC within the context of a R-parity violating supersymmetric model. We present next to leading order QCD corrections to total cross sections which originate from both quark- as well as gluon-initiated processes. For couplings involving only the first

Adam K. Leibovich

The standard NRQCD power counting breaks down and the OPE gives rise to color-octet shape functions at the upper endpoint of the photon energy spectrum in radiative Upsilon decay. Also in this kinematic regime, large Sudakov logarithms appear in the octet Wilson coefficients, ruining the perturbative expansion. Using SCET, the octet shape functions arise nat

Ian Low, Witold Skiba, David Smith

We construct an SU(6)/Sp(6) non-linear sigma model in which the Higgses arise as pseudo-Goldstone bosons. There are two Higgs doublets whose masses have no one-loop quadratic sensitivity to the cutoff of the effective theory, which can be at around 10 TeV. The Higgs potential is generated by gauge and Yukawa interactions, and is distinctly different from tha

P. H. Chankowski, J. Rosiek

Recent development in exploring flavour dynamics in the supersymmetric extension of the Standard Model is reviewed. Emphasis is put on possible interesting effects in b-physics arising for large values of tan beta both in the case of minimal flavour violation and in the case of flavour violation originating in the sfermion sector. The importance of the flavo

M. Hirsch, M. A. Diaz, W. Porod, J. C. Romao

We show how Bilinear R-Parity violation within the Minimal Supersymmetric Standard Model can solve the atmospheric and solar neutrino problems by generating naturally small and hierarchical neutrino masses, together with neutrino mixing angles consistent with experiments. The relation between collider and neutrino physics is emphasized.

John P. Costella

In this paper I propose the use of a lattice derivative operator that is equivalent to the ideal SLAC derivative operator in all lattice calculations, but without the prohibitively expensive computational cost of the latter. A pedagogical motivation and derivation of the closed form of the SLAC derivative in position space is presented, and the proposed meth

The FOCUS Collaboration

Using a large sample of D+ to K- pi+ mu+ nu decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of two semileptonic form factor ratios: rv and r2. We find rv = 1.504 \pm 0.057 \pm 0.039 and r2 = 0.875 \pm 0.049 \pm 0.064. Our form factor results include the effects of the s-wave interference discussed in a previo

SLD Collaboration

A search for Bs0-Bs0bar oscillations is performed using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The Bs0 candidates are reconstructed in the Bs0 to Ds-,X channel with Ds- to phi,pi- or K*0K-. The Bs0 production flavor is determined using the large forward-backward asymmetry of polarized Z0 to b,bbar decays and charge informatio

C. R. Locke, M. E. Tobar, E. N. Ivanov

To measure the standard quantum limit (SQL) a high quality transducer must be coupled to a high quality mechanical system. Due to its monolithic nature, the monolithic sapphire transducer (MST) has high quality factors for both types of resonances. Single loop suspension is shown to yield a mechanical quality factor of 6.10^8 at 4 K. From standard analysis w

David Pearce, Vladimir Sarsakov, Torsten Schaub, Hans Tompits

Nested logic programs have recently been introduced in order to allow for arbitrarily nested formulas in the heads and the bodies of logic program rules under the answer sets semantics. Nested expressions can be formed using conjunction, disjunction, as well as the negation as failure operator in an unrestricted fashion. This provides a very flexible and com

A. A. Bokov, Z. -G. Ye

The dielectric permittivity e at frequencies from [10^(-1) -10^(-5)] Hz to 10^5 Hz is studied in perovskite (1-x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 relaxor ferroelectric ceramics of different compositions x = 0.35, 0.25 and 0, which exhibit, below the temperature of the diffuse epsilon&#39;(T) maximum Tm, a tetragonal ferroelectric, a rhombohedral ferroelectric and

Olaf Wunnicke, Phivos Mavropoulos, Peter H. Dederichs

We calculate the current spin polarisation and the interface resistance of Fe/GaAs and Fe/ZnSe (001) spin injection junctions from first principles, including also the possibility of a Schottky barrier. From our results of interface resistance we estimate the barrier thickness needed for efficient spin injection if the process is non-ballistic.

Ch. Helm, L. N. Bulaevskii

We study the optical properties of crystals with spatial dispersion and show that the usual Fresnel approach becomes invalid near frequencies where the group velocity of the wave packets inside the crystal vanishes. Near these special frequencies the reflectivity depends on the atomic structure of the crystal provided that disorder and dissipation are very l

Mario D&#39;Acunto

The paper presents a model for low friction made up of a self-excited oscillator sliding along a periodic potential. It is shown that if the self-excitation affects a body sliding tangentially to a surface, than stick-slip modification and reduction of energy dissipation during the motion are observed.

N. Garcia, M. Nieto-Vesperinas

Comment on &#39;&#39;Electromagnetic Surface Modes at Interfaces with Negative Refractive Index make a Non-Quite Perfect Lens&#39;&#39;

G. Giunchi, S. Ceresara, G. Ripamonti, A. DiZenobio

MgB2 hollow wires have been produced with a new technique which uses a conventional wire manufacturing process but is applied to composite billets containing the elemental B and Mg precursors in an appropriate shape. The technique has been applied to the manufacture of both monofilamentary and multifilamentary wires of several tens meters length. The superco

Pasquale Calabrese, Andrea Gambassi

We consider the out-of-equilibrium, purely relaxational dynamics of a weakly diluted Ising model in the aging regime at criticality. We derive at first order in a $\sqrtε$ expansion the two-time response and correlation functions for vanishing momenta. The long-time limit of the critical fluctuation-dissipation ratio is computed at the same order in perturba

G. A. Khodaparast, J. Kono, Y. H. Matsuda, T. Ikaida

We report the first observation of hole cyclotron resonance (CR) in ferromagnetic InMnAs/GaSb heterostructures both in the high-temperature paramagnetic phase and the low-temperature ferromagnetic phase. We clearly resolve two resonances that exhibit strong temperature dependence in position, linewidth, and intensity. We attribute the two resonances to the s

M. H. Hettler, W. Wenzel, M. R. Wegewijs, H. Schoeller

We investigate the electrical transport through a system of benzene coupled to metal electrodes by electron tunneling. Using electronic structure calculations, a semi--quantitative model for the pi-electrons of the benzene is derived that includes general two-body interactions. After exact diagonalization of the benzene model the transport is computed using

V. Subrahmanyam

We study a harmonically-confined Bose-Einstein condensate under rotation. Vortex lattice configurations are investigated through a variational approach. Vortices with more than a unit of angular momentum are not stable. We explicitly show that the critical rotational frequency is quite small, as was reported in the MIT experiment. The width of the condensate

Yu. V. Tarasov

The conductance of a disordered finite-size electron system is calculated by reducing the initial dynamic problem of arbitrary dimensionality to strictly one-dimensional problems for one-particle mode propagators. The metallic ground state of a two-dimensional conductor, which is considered as a limiting case of the actually three-dimensional quantum wavegui

S. Kalavathi, J. Janaki, G. V. N. Rao, V. Sankara Sastry

The structural, electrical and magnetic properties of the superconducting ferromagnets, Gd1.4-xDyxCe0.6Sr2RuCu2O10 (x=0-0.6) are systematically investigated as a function of Dy doping and temperature. These compounds are characterised by high temperature superconductivity (Tc ranging from 20-40 K depending upon the Dy content) coexisting with weak ferromagne

Farshid Mohammad-Rafiee, Ramin Golestanian

The response of a short DNA segment to bending is studied, taking into account the anisotropy in the bending rigidities caused by the double-helical structure. It is shown that the anisotropy introduces an effective nonlinear twist-bend coupling that can lead to the formation of kinks and modulations in the curvature and/or in the twist, depending on the val

Y. Malevergne, D. Sornette

We introduce a new set of consistent measures of risks, in terms of the semi-invariants of pdf&#39;s, such that the centered moments and the cumulants of the portfolio distribution of returns that put more emphasis on the tail the distributions. We derive generalized efficient frontiers, based on these novel measures of risks and present the generalized CAPM

P. Dalmas de Reotier, A. Yaouanc

We present a discussion of published x-ray magnetic circular dichroism (XMCD) measurements performed at the uranium M_4,5 edges of metallic uranium compounds, focusing on the shape of the dichroic signal at the M_5 edge. A well resolved double lobe structure, comprised of a positive and a negative peak, is sometimes observed. Out of the twelve metallic urani

Yadong Wei, Jian Wang

Parametric electron pump through superconductor-carbon-nanotube based molecular devices was investigated. It is found that a dc current, which is assisted by resonant Andreev reflection, can be pumped out from such molecular device by a cyclic variation of two gate voltages near the nanotube. The pumped current can be either positive or negative under differ

E. Simanek, B. Heinrich

We study the enhancement of the ferromagnetic relaxation rate in thin films due to the adjacent normal metal layers. Using linear response theory, we derive the dissipative torque produced by the s-d exchange interaction at the ferromagnet-normal metal interface. For a slow precession, the enhancement of Gilbert damping constant is proportional to the square