June 1999 arXiv papers — page 20

Avner Ash, Warren Sinnott

The conjecture of Serre referred in the title is the one about modularity of odd Galois representations into GL(2,F) where F is a finite field of characteristic p. We present an analogous conjecture where GL(2) is replaced by GL(n). We explain the analogue of "oddness." We then present some theoretical and experimental evidence for the conjecture, pr

Charles F. Dunkl

The hyperoctahedral group is the Weyl group of type B and is associated with a two-parameter family of differential-difference operators T_i, i=1,..,N (the dimension of the underlying Euclidean space). These operators are analogous to partial derivative operators. This paper finds all the polynomials in N variables which are annihilated by the sum of the squ

E. J. Beggs, S. Majid

We introduce a new 2-parameter family of sigma models exhibiting Poisson-Lie T-duality on a quasitriangular Poisson-Lie group $G$. The models contain previously known models as well as a new 1-parameter line of models having the novel feature that the Lagrangian takes the simple form $L=E(u^{-1}u_+,u^{-1}u_-)$ where the generalised metric $E$ is constant (no

Andreas Gustavsson, Mans Henningson

We consider N = 2 super Yang-Mills theory with SU(2) gauge group and a single quark hypermultiplet in the fundamental representation. For a specific value of the quark bare mass and at a certain point in the moduli space of vacua, the central charges corresponding to two mutually non-local electro-magnetic charges vanish simultaneously, indicating the possib

J. A. Casas, J. R. Espinosa, A. Ibarra, I. Navarro

The vacuum oscillation (VO) solution to the solar anomaly requires an extremely small neutrino mass splitting, Delta m^2_{sol}\leq 10^{-10} eV^2. We study under which circumstances this small splitting (whatever its origin) is or is not spoiled by radiative corrections. The results depend dramatically on the type of neutrino spectrum. If m_1^2 \sim m_2^2 \ge

C. A. Dominguez, M. Loewe, C. van Gend

A thermal QCD Finite Energy Sum Rule (FESR) is used to obtain the temperature dependence of the axial-vector coupling of the nucleon, $g_{A}(T)$. We find that $g_{A}(T)$ is essentially independent of $T$, in the very wide range $0 \leq T \leq 0.9 T_{c}$, where $T_{c}$ is the critical temperature. While $g_{A}$ at T=0 is $q^{2}$-independent, it develops a $q^

Vittorio Del Duca

The BFKL resummation at LL and NLL accuracy is briefly reviewed, with particular emphasis on the connection between the NLL corrections to the BFKL equation and exact NNLO calculations.

S. Jadach, W. Placzek, M. Skrzypek, B. F. L. Ward

The Monte Carlo program KoralW version 1.42 is presented. It generates all four-fermion final states with multibranch dedicated Monte Carlo pre-samplers and complete, massive, Born matrix elements. The presamplers cover the entire phase space. Multiphoton bremsstrahlung is implemented in the ISR approximation within the YFS formulation with the O(alpha**3) l

F. Benatti, R. Floreanini

The time evolution and decay of the neutral kaon system can be described using quantum dynamical semigroups. Non-standard terms appear in the expression of relevant observables; they can be parametrized in terms of six, new phenomenological constants. We discuss how the presence of these constants affects the determination of the parameter epsilon'/epsil

K. S. Babu, R. N. Mohapatra

Supersymmetric gauge models with local horizontal symmetries are known to generate large flavor changing neutral current effects induced by supersymmetry breaking D-terms. We show how the presence of a U(1) gauge symmetry solves this problem. We then construct a realistic gauge model with SU(2)_H x U(1)_H as the local horizontal symmetry and suggest that the

S. M. Bilenky, A. Geiser, C. Giunti, S. Mohanty

Summary of the Phenomenology Working Group at the Europhysics Neutrino Oscillation Workshop (NOW'98), 7-9 September 1998, Amsterdam.

M. Apollonio, A. Baldini, C. Bemporad, E. Caffau

The CHOOZ experiment measured the antineutrino flux at a distance of about 1 Km from two nuclear reactors in order to detect possible neutrino oscillations with squared mass differences as low as 10**-3 eV**2 for full mixing. We show that the data analysis of the electron antineutrino events, collected by our liquid scintillation detector, locates the antine

John Ellis, N. E. Mavromatos, D. V. Nanopoulos

We present a microscopic model for light-cone fluctuations ``in vacuo'', which incorporates a treatment of quantum-gravitational recoil effects induced by energetic particles. Treating defects in space-time as solitons in string theory, we derive an energy-dependent refractive index and a stochastic spread in the arrival times of mono-energetic photo

Alberto Saa, Roberto Venegeroles

Motivated by the strong astronomical evidences supporting that huge black-holes might inhabit the center of many active galaxies, we have studied the integrability of oblique orbits of test particles around the exact superposition of a black-hole and a thin disk. We have considered the relativistic and the Newtonian limits. Exhaustive numerical analyses were

E. I. Guendelman

Conserved quantities are obtained and analyzed in the new models with global scale invariance recently proposed. Such models allow for non tivial scalar field potentials and masses for particles, so that the scale symmetry must be broken somehow. We get to this conclusion by showing that the infrared behavior of the conserved currents is singular so that the

Victor Makarov

Predicate Logic with Definitions (PLD or D-logic) is a modification of first-order logic intended mostly for practical formalization of mathematics. The main syntactic constructs of D-logic are terms, formulas and definitions. A definition is a definition of variables, a definition of constants, or a composite definition (D-logic has also abbreviation defini

M. E. Portnoi, I. Galbraith

The degree of ionization of a nondegenerate two-dimensional electron-hole plasma is calculated using the modified law of mass action, which takes into account all bound and unbound states in a screened Coulomb potential. Application of the variable phase method to this potential allows us to treat scattering and bound states on the same footing. Inclusion of

V. Petkov, I-K. Jeong, J. S. Chung, M. F. Thorpe

High real-space resolution atomic pair distribution functions (PDF)s from the alloy series Ga_1-xIn_xAs have been obtained using high-energy x-ray diffraction. The first peak in the PDF is resolved as a doublet due to the presence of two nearest neighbor bond lengths, Ga-As and In-As, as previously observed using XAFS. The widths of nearest, and higher, neig

Giorgio Parisi, Nicolas Sourlas

The p-adic formulation of replica symmetry breaking is presented. In this approach ultrametricity is a natural consequence of the basic properties of the p-adic numbers. Many properties can be simply derived in this approach and p-adic Fourier transform seems to be an promising tool.

Claudio Castellano, Marco Zannetti

The evolution of the structure factor is studied during the phase-ordering dynamics of the kinetic Ising model with conserved order parameter. A preasymptotic multiscaling regime is found as in the solution of the Cahn-Hilliard-Cook equation, revealing that the late stage of phase-ordering is always approached through a crossover from multiscaling to standar

Yukihiro Okuno, Masashige Matsumoto, Mangred Sigrist

The microscopic mechanism of circular currents induced in the vicinity of a non-magnetic impurity is analyzed for the (time-reversal symmetry breaking) chiral superconducting state ${\bf d}({\bf k}) = \hat{\bf z} (k_x \pm i k_y)$ which is very likely realized in Sr_2RuO_4. From the analytic, not self-consistent solution of the Bogolyubov-de Gennes equations

Martin Holthaus, Eva Kalinowski

The application of the conventional saddle-point approximation to condensed Bose gases is thwarted by the approach of the saddle-point to the ground-state singularity of the grand canonical partition function. We develop and test a variant of the saddle-point method which takes proper care of this complication, and provides accurate, flexible, and computatio

P. Monthoux, G. G. Lonzarich

We compare predictions of the mean-field theory of superconductivity for nearly antiferromagnetic and nearly ferromagnetic metals in two dimensions. The calculations are based on a parametrization of the effective interaction arising from the exchange of magnetic fluctuations. The Eliashberg equations for the transition temperature are solved including the f

H. R. W. Beljaars, A. van Heukelum

The cage model for polymer reptation is extended to simulate DC electrophoresis. The drift velocity v of a polymer with length L in an electric field with strength E shows three different regions: if the strength of field is small, the drift velocity scales as E/L; for slightly larger strengths, it scales as E^2, independent of length; for high fields, but s

U. Nowak, R. W. Chantrell, E. C. Kennedy

For the description of thermally activated dynamics in systems of classical magnetic moments numerical methods are desirable. We consider a simple model for isolated magnetic particles in a uniform field with an oblique angle to the easy axis of the particles. For this model, a comparison of the Monte Carlo method with Langevin dynamics yields new insight in

Arindam Ghosh, A. K. Raychaudhuri

In this paper we report measurements of conductance fluctuations in single crystal samples of Si doped with P and B close to the critical composition of the metal insulator transition (n_c \approx 4 x 10^18 /cc). The measurements show that the noise, which arises from bulk sources, does not diverge as the Ioffe-Regal limit (k_{F}l -> 1) is approached from th

Mitsuaki Takigawa, Masanori Ichioka, Kazushige Machida

The temperature dependence of the site-dependent nuclear spin relaxation time T_1 around vortices is studied in s-wave and d-wave superconductors.Reflecting low energy electronic excitations associated with the vortex core, temperature dependences deviate from those of the zero-field case, and T_1 becomes faster with approaching the vortex core. In the core

Evgeny V. Pechen

A special shaping of YAG:Nd^{3+} laser beam profile has been found to improve homogeneity and T_c of YBa_2Cu_3O_{7-δ} films being deposited by the pulsed laser. Targets of a considerably non-stoichiometric composition and substrates of slanting cuts have turned to be necessary for the high-quality film growing. Multiple droplets and solid particles ejected f

Carme Gallart, Wendy Freedman, Antonio Aparicio, Gianpaolo Bertelli

We present a quantitative analysis of the star formation history (SFH) of the Local Group dSph galaxy Leo I, from the information in its HST [(V-I),I] color-magnitude diagram (CMD). The method we use is based in comparing, via synthetic CMDs, the expected distribution of stars in the CMD for different evolutionary scenarios, with the observed distribution. W

P. A. M. van Hoof, R. D. Oudmaijer, L. B. F. M. Waters

A parameter study of the spectral evolution of a typical post-AGB star, with particular emphasis on the evolution of the infrared colours, is presented. The models are based on the latest evolutionary tracks for hydrogen burning post-AGB stars. For such tracks the evolutionary rate is very dependent on the assumed mass loss rate as a function of time. We inv

Ewine F. van Dishoeck, Michiel R. Hogerheijde

The study of the chemical evolution of gas and dust from pre-stellar dense cores to circumstellar disks around young stars forms an essential part of understanding star- and planet formation. Throughout the collapse- and protostellar phases, simple and complex molecules are formed, many of which deplete onto cold grains and are eventually incorporated into t

Whipple Collaboration, R. W. Lessard, I. H. Bond, P. J. Boyle

If cosmic rays with energies <100 TeV originate in the galaxy and are accelerated in shock waves in shell-type supernova remnants (SNRs), gamma-rays will be produced as the result of proton and electron interactions with the local interstellar medium, and by inverse Compton emission from electrons scattering soft photon fields. We report on observations of t

P. P. Avelino, C. J. A. P. Martins

We propose a new generalisation of general relativity which incorporates a variation in both the speed of light in vacuum (c) and the gravitational constant (G) and which is both covariant and Lorentz invariant. We solve the generalised Einstein equations for Friedmann universes and show that arbitrary time-variations of c and G never lead to a solution to t

Anita Krishnamurthi, Giuseppe Leto, Jeffrey L. Linsky

We have used the VLA to conduct a deep search for 3.6 cm radio emission from nearby very low mass stars and brown dwarfs. The Gudel-Benz relation is used to predict radio luminosities for some very low mass stars and candidate brown dwarfs with measured X-ray fluxes. The predicted radio fluxes are quite small, whereas the measured radio flux from the brown d

Marco Lombardi, Giuseppe Bertin

Statistical analyses of observed galaxy distortions are often used to reconstruct the mass distribution of an intervening cluster responsible for gravitational lensing. In current projects, distortions of thousands of source galaxies have to be handled efficiently; much larger data bases and more massive investigations are envisaged for new major observation

U. D. J. Gieseler, T. W. Jones, Hyesung Kang

The theory of diffusive particle acceleration explains the spectral properties of the cosmic rays below energies of approx. 10^6 GeV as produced at strong shocks in supernova remnants (SNR&#39;s). To supply the observed flux of cosmic rays, a significant fraction of the energy released by a supernova has to be transfered to cosmic rays. The key to the questi

U. D. J. Gieseler, J. G. Kirk

Supernova remnants are expected to contain braided (or stochastic) magnetic fields, which are in some regions directed mainly perpendicular to the shock normal. For particle acceleration due to repeated shock crossings, the transport in the direction of the shock normal is crucial. The mean squared deviation along the shock normal is then proportional to the

Gabriele Ghisellini

The discovery of strong gamma-ray and hard X-ray emission and the results from various multifrequency campaigns have disclosed new aspects of the blazar phenomenology, leading to a much more robust understanding of the mechanisms underlying their emission, and offering clues for the energetics of their relativistic jets. I review these aspects, and propose t

Linqing Wen, Wei Cui, Alan M. Levine, Hale V. Bradt

We have analyzed over 2 years of RXTE/ASM data for Cygnus X-1. We have detected the 5.6-day orbital period in Lomb-Scargle periodograms of both light curves and hardness ratios when Cyg X-1 was in the hard state. This detection was made with improved sensitivity and temporal coverage compared with previous detections by other X-ray missions. The folded light

M. A. Garrett, R. W. Porcas, A. Pedlar, T. W. B. Muxlow

We discuss the technique of Wide-field imaging as it applies to Very Long Baseline Interferometry (VLBI). In the past VLBI data sets were usually averaged so severely that the field-of-view was typically restricted to regions extending a few hundred milliarcseconds from the phase centre of the field. Recent advances in data analysis techniques, together with

F. Barone, R. De Rosa, A. Eleuteri, F. Garufi

In this paper a Neural Network based approach is presented to identify the noise in the VIRGO context. VIRGO is an experiment to detect Gravitational Waves by means of a Laser Interferometer. Preliminary results appear to be very promising for data analysis of realistic Interferometer outputs.

J. B. Stephens, M. J. Coe, D. A. H. Buckley

The fields of 8 X-ray sources in the Magellanic Clouds believed to be Be/X-ray binaries have been searched for possible Be star counterparts. BVR and H alpha CCD imaging was employed to identify early type emission stars through colour indices and H alpha fluxes. Spectroscopy of 5 sources confirms the presence of H alpha emission in each case. Based on the p

C. Sauty, K. Tsinganos, E. Trussoni

An axisymmetric MHD model is examined analytically to illustrate some key aspects of the physics of hot and magnetized outflows which originate in the near environment of a central gravitating body. By analyzing the asymptotical behaviour of the outflows it is found that they attain a variety of shapes such as conical, paraboloidal or cylindrical. However, n

Tsafrir S. Kolatt, James S. Bullock, Rachel S. Somerville, Yair Sigad

Lyman break galaxies (LBGs) at $z \sim 3$ exhibit number densities and clustering similar to local $L_*$ galaxies; however, their star formation rates (SFRs) are much higher. We explore the scenario in which LBGs are starburst galaxies triggered by collisions, and thus provide an explanation for these key properties. The relative paucity of starburst galaxie

N. Menci, A. Cavaliere

Using current semi-analytic models of structure and star formation based on hierarchical clustering, we connect the cosmic star formation rate (SFR) to the X-ray emission properties of groups and clusters of galaxies. We show that when the baryons cool down from a hot phase to condense into stars with a SFR flat for z>2, then such hot phase yields deep X-ray

F. Piron

The gamma-ray emission of the blazar Markarian 421 above 250 GeV has been observed by the CAT Cherenkov imaging telescope since December, 1996. We report here results on the source variability up to April, 1998, with emphasis on the 1998 campaign. For the flaring periods of this year, the energy spectrum was derived from 330 GeV up to 5.2 TeV: it is very wel

T. R. Marsh

I review detached binaries consisting of white dwarfs with either other white dwarfs or low mass main-sequence stars in tight orbits around them. Orbital periods have been measured for 15 white dwarf/white dwarf systems and 22 white dwarf/M dwarf systems. While small compared to the number of periods known for CVs (>300), I argue that each variety of detache

S. Andreon, G. Gargiulo, G. Longo, R. Tagliaferri

One of the most relevant problems in the extraction of scientifically useful information from wide field astronomical images (both photographic plates and CCD frames) is the recognition of the objects against a noisy background and their classification in unresolved (star-like) and resolved (galaxies) sources. In this paper we present a neural network based

R. Tagliaferri, A. Ciaramella, L. Milano, F. Barone

In this paper we present a hybrid system composed by a neural network based estimator system and genetic algorithms. It uses an unsupervised Hebbian nonlinear neural algorithm to extract the principal components which, in turn, are used by the MUSIC frequency estimator algorithm to extract the frequencies. We generalize this method to avoid an interpolation

A. S. Mikhailov, D. H. Zanette

We consider swarms formed by populations of self-propelled particles with attractive long-range interactions. These swarms represent multistable dynamical systems and can be found either in coherent traveling states or in an incoherent oscillatory state where translational motion of the entire swarm is absent. Under increasing the noise intensity, the cohere

J. F. Gunion, S. Mrenna

For some choices of soft SUSY-breaking parameters, the LSP is a stable neutralino $\cnone$, the NLSP is a chargino $\cpmone$ almost degenerate in mass with the LSP ($\dmchi\equiv\mcpmone-\mcnone\sim \mpi-$few GeV), and all other sparticles are relatively heavy. In this case, detection of sparticles in the usual, mSUGRA-motivated signals will be difficult, si

Yan V. Fyodorov

Our goal is to study statistical properies of &#34;dielectric resonances&#34; which are poles of conductance of a large random $LC$ network. Such poles are a particular example of eigenvalues $λ_n$ of matrix pencils ${\bf H}-λ{\bf W}$, with ${\bf W}$ being positive definite matrix and ${\bf H}$ a random real symmetric one. We first consider spectra of matrix

A. Strumia

Within a minimal extension of the SM in 4+1 dimensions, we study how Kaluza Klein excitations of the SM gauge bosons affect the electroweak precision observables. Asymmetries in Z decays provide the dominant bound on the compactification scale M of the extra dimension. If the higgs is so light that will be discovered at LEP2, we find the following 95% CL bou

Heng Fan, Miki Wadati, Xiao-man Wang

We study the generalized supersymmetric $t-J$ model with boundaries in three different gradings: FFB, BFF and FBF. Starting from the trigonometric R-matrix, and in the framework of the graded quantum inverse scattering method (QISM), we solve the eigenvalue problems for the supersymmetric $t-J$ model. A detailed calculations are presented to obtain the eigen

P. van Loock, Samuel L. Braunstein

We show that {\it one} single-mode squeezed state distributed among $N$ parties using linear optics suffices to produce a truly $N$-partite entangled state for any nonzero squeezing and arbitrarily many parties. From this $N$-partite entangled state, via quadrature measurements of $N-2$ modes, bipartite entanglement between any two of the $N$ parties can be

I. Ya. Aref&#39;eva, I. V. Volovich

There exists the well known approximate expression describing the large time behaviour of matrix elements of the evolution operator in quantum theory: <U(t)>=exp(at)+... This expression plays the crucial role in considerations of problems of quantum decoherence, radiation, decay, scattering theory, stochastic limit, derivation of master and kinetic equations

Ioan Sturzu

The paper emphasis the role of unsharpness in the body of Quantum Theory and the relations to the conceptual problems of the Theory. Key words: quantum measurement, unsharpness, effect, positive operator-valued measure

Lucian M. Ionescu

We review several known categorification procedures, and introduce a functorial categorification of group extensions with applications to non-abelian group cohomology. Categorification of acyclic models and of topological spaces are briefly mentioned.

Pierre Baumann, Christian Kassel

To an abelian category A of homological dimension 1 satisfying certain finiteness conditions, one can associate an algebra, called the Hall algebra. Kapranov studied this algebra when A is the category of coherent sheaves over a smooth projective curve defined over a finite field, and observed analogies with quantum affine algebras. We recover here in an ele

M. Deza, M. I. Shtogrin

We explore some generalizations of fullerenes F_v (simple polyhedra with v vertices and only 5- and 6-gonal faces) seen as (d-1)-dimensional simple manifolds (preferably, spherical or polytopal) with only 5- and 6-gonal 2-faces. First, finite and planar (infinite) 3-fullerenes are described. Three infinite families of spherical 4-fullerenes are presented in

M. Deza, M. I. Shtogrin

We review 28 uniform partitions of 3-space in order to find out which of them have graphs (skeletons) embeddable isometrically (or with scale 2) into some cubic lattice ${\bf Z}_n$. We also consider some relatives of those 28 partitions, including Achimedean 4-polytopes of Conway-Guy, non-compact uniform partitions, Kelvin partitions and those with unique ve

L. Rozansky

We use the properties of the Melvin-Morton expansion of the colored Jones polynomial in order to prove that the trivial connection contribution converges p-adicly to the SO(3) Witten-Reshetikhin-Turaev invariant of rational homology spheres, as it was conjectured by R. Lawrence.

L. Rozansky

We extend the definition of the U(1)-reducible connection contribution to the case of the Witten-Reshetikhin-Turaev invariant of a link in a rational homology sphere. We prove that, similarly ot the case of a link in S^3, this contribution is a formal power series in powers of q-1, whose coefficients are rational functions of q^{color}, their denominators be

L. Rozansky

We use the relation between the quantum su(2) R-matrix and the Burau representation of the braid group in order to study the structure of the colored Jones polynomial of links. We show that similarly to the case of a knot, the colored Jones polynomial of a link can be presented as a formal series in powers of q-1. The coefficients of this series are rational

B. Eden, P. S. Howe, C. Schubert, E. Sokatchev

The superconformal Ward identities combined with N=2 harmonic analyticity are used to evaluate two-loop four-point correlation functions of gauge-invariant operators in D=4, N=4 supersymmetric Yang-Mills theory in terms of the well-known one-loop box integral. The result is confirmed by a direct numerical computation.

S. Gardner

An isospin analysis of $B\to ππ$ decays yields $\sin 2α$, where $α$ is the usual CKM angle $α\equiv {\rm arg} [-V_{td} V_{tb}^\ast/(V_{ud}V_{ub}^\ast)]$ without hadronic uncertainty if isospin is a perfect symmetry. Yet isospin symmetry is broken not only by electroweak effects but also by the $u$ and $d$ quark mass difference --- the latter drives $π^0-η,η&

K. Maltman

The isovector scalar correlator is studied using a class of finite energy sum rules shown recently to be very well satisfied in the vector isovector channel. The values of the $a_0$ scalar decay constants extracted in this analysis, which describe the couplings of the $a_0(980)$ and $a_0(1450)$ to the isovector scalar current, are shown to be comparable, str

G. Modanese

The positive energy theorem precludes the possibility of Minkowski flat space decaying by any mechanism. In certain circumstances, however, large quantum fluctuations of the gravitational field could arise---not only at the Planck scale, but also at larger scales. This is because there exists a set of localised weak field configurations which satisfy the con

Thorsten Brants

This paper presents a new approach to partial parsing of context-free structures. The approach is based on Markov Models. Each layer of the resulting structure is represented by its own Markov Model, and output of a lower layer is passed as input to the next higher layer. An empirical evaluation of the method yields very good results for NP/PP chunking of Ge

A. P. Dmitriev, V. Yu. Kachorovskii

We study level correlations in a two-dimensional system with a long-range random potential and strong spin-orbit (SO) splitting of the spectrum. The level correlations for sufficiently large splitting are shown to be described by orthogonal Wigner-Dyson statistics, in contrast to the common point of view that a system with the strong SO coupling belongs to t

Z. Neda, A. Rusz, E. Ravasz, P. Lakdawala

The 1D Ising model is analytically studied in a spatially periodic and oscillatory external magnetic field using the transfer-matrix method. For low enough magnetic field intensities the correlation between the external magnetic field and the response in magnetization presents a maximum for a given temperature. The phenomenon can be interpreted as a resonanc

E. Kececioglu, B. Tanatar, M. Cemal Yalabik

We study stochastic ratchets with inertia in the limit where the time correlations become important. We have developed a Fokker-Planck type equation for the ratchet problem which includes the memory effects. It is tested with comparison to the Langevin simulations. The effect of the memory in the system is analyzed extensively. A positive feedback regime whi

F. Sciortino, W. Kob, P. Tartaglia

We present a quantitative description of the thermodynamics in a supercooled binary Lennard Jones liquid via the evaluation of the degeneracy of the inherent structures, i.e. of the number of potential energy basins in configuration space. We find that for supercooled states, the contribution of the inherent structures to the free energy of the liquid almost

Y. Levinson, P. Woelfle

We propose a new approach to calculate current and current correlations in a ballistic quantum point contact interacting with a classical field. The approach is based on the concept of scattering states for a time dependent Hamiltonian neglecting electron-electron interaction. Using this approach we calculated the spectra of the current noise in a biased poi

Henrique R. Schmitt

Spectral energy distributions (SEDs) are some of the most important sources of information for galaxies, especially for high redshift ones. Here we review recent work on the subject. We discuss the integrated spectra of galaxies of different morphological and activity type, their application to derive K-corrections and classification of high redshift objects

Apostolos Pilaftsis

We study the scenario of baryogenesis through leptogenesis in higher-dimensional theories, in which the scale of quantum gravity is many orders of magnitude smaller than the usual Planck mass. The minimal realization of these theories includes an isosinglet neutrino which feels the presence of large compact dimensions, whereas all the SM particles are locali

E. Marinari, G. Parisi, F. Ricci-Tersenghi, J. Ruiz-Lorenzo

We discuss replica symmetry breaking (RSB) in spin glasses. We update work in this area, from both the analytical and numerical points of view. We give particular attention to the difficulties stressed by Newman and Stein concerning the problem of constructing pure states in spin glass systems. We mainly discuss what happens in finite-dimensional, realistic

Daijiro Yoshioka

General rule for the composite fermion transformation, when the spins of the electrons are not polarized is derived. Condition for the quantum phase transition between various spin states is obtained based on the rule. This rule gives foundation for the experimental determination of the mass and $g$-factor of the composite fermion.

Guido Burkard, Daniel Loss, Eugene V. Sukhorukov

Addressing the feasibility of quantum communication with entangled electrons in an interacting many-body environment, we propose an interference experiment using a scattering set-up with an entangler and a beam splitter. It is shown that, due to electron-electron interaction, the fidelity of the entangled singlet and triplet states is reduced by z_F^2 in a c

Gian Luigi Alberghi, David A. Lowe, Mark Trodden

We initiate a study of cosmology within the framework of Maldacena&#39;s AdS/CFT correspondence. We present a comprehensive analysis of the classical motion of a charged domain wall that separates an external Reissner-Nordstrom region of spacetime (with small or vanishing cosmological constant) from an internal de-Sitter region. The possible associated space

Gui Lu Long, Yan Song Li, Wei Lin Zhang, Li Niu

Each iteration in Grover&#39;s original quantum search algorithm contains 4 steps: two Hadamard-Walsh transformations and two amplitudes inversions. When the inversion of the marked state is replaced by arbitrary phase rotation θand the inversion for the prepared state |γ> is replaced by rotation through ϕ, we found that these phase rotations must satisfy a

Dmitry V. Skryabin, William J. Firth

We investigate stability and dynamics of higher-order solitary waves in quadratic media, which have a central peak and one or more surrounding rings. We show existence of two qualitatively different behaviours. For positive phase mismatch the rings break up into filaments which move radially to initial ring. For sufficient negative mismatches rings are found

Dmitry V. Skryabin, William J. Firth

We present a detailed analysis of the modulational instability (MI) of ground-state bright solitary solutions of two incoherently coupled nonlinear Schrödinger equations. Varying the relative strength of cross-phase and self-phase effects we show existence and origin of four branches of MI of the two-wave solitary solutions. We give a physical interpretation

Dmitry V. Skryabin, William J. Firth

We show how the analytical approach of Zakharov and Rubenchik [Sov. Phys. JETP {\bf 38}, 494 (1974)] to modulational instability (MI) of solitary waves in the nonlinear Schröedinger equation (NLS) can be generalised for models with two phase symmetries. MI of three-wave parametric spatial solitons due to group velocity dispersion (GVD) is investigated as a t

Hua Ying Ji, Gui Lu Long, En Guang Zhao, Shu Wei Xu

Spectrum and electric dipole transition rates and relative intensities in $^{152-154}$Sm, $^{156-160}$Gd, $^{160-162}$Dy are studied in the framework of the interacting boson model with s,p,d,f bosons. It is found that E1 transition data among the low-lying levels are in good agreement with the SU(3) dynamical symmetry of the spdf interacting boson model pro

M. Bawin, S. A. Coon

We consider the Dirac equation for a finite-size neutron in an external electric field. We explicitly incorporate Dirac-Pauli form factors into the Dirac equation. After a non-relativistic reduction, the Darwin-Foldy term is cancelled by a contribution from the Dirac form factor, so that the only coefficient of the external field charge density is $e/6 r^2_{

Robert Cowen

A set-theoretic property called Property S is introduced as a generalization of the well-known Property B. Property S is named for A.Schrijver who first used it to formulate an equivalent of the boolean prime ideal theorem. It was independently introduced by A. Kolany to give a uniform treatment for a variety of satisfiability problems who then used a genera

Johannes Huebschmann

Berikashvili&#39;s functor D defined in terms of twisting cochains is related to deformation theory, gauge theory, Chen&#39;s formal power series connections, and the master equation in physics. The idea is advertised that some unification and understanding of the links between these topics is provided by the notion of twisting cochain and the idea of classi

Stanislav Klimenko, Igor Nikitin

Solutions of classical string theory, correspondent to the world sheets, mapped in Minkowsky space with a fold, are considered. Typical processes for them are creation of strings from vacuum, their recombination and annihilation. These solutions violate positiveness of square of mass and Regge condition. In quantum string theory these solutions correspond to

M. Shifman

Powerful methods based on supersymmetry allow one to find exact solutions to certain problems in strong coupling gauge theories. The inception of some of these methods (holomorphy in the gauge coupling and other chiral parameters, in conjunction with instanton calculations) dates back to the 1980&#39;s. I describe the early exact results -- the calculation o

E. Kiritsis, T. R. Taylor

We discuss the dynamics and thermodynamics of particle and D-brane probes moving in non-extremal black hole/brane backgrounds. When a probe falls from asymptotic infinity to the horizon, it transforms its potential energy into heat, $TdS$, which is absorbed by the black hole in a way consistent with the first law of thermodynamics. We show that the same rema

V. I. Zakharov

We review briefly and in retrospect the development which brought about the QCD sum rules based on introduction of the gluon condensate (M.A. Shifman, A.I. Vainshtein, and V.I. Zakharov (1978)).

Arkady Vainshtein

A mechanism explaining a strong enhancement of nonleptonic weak decays was suggested in 1975, later to be dubbed the penguin. This mechanism extends Wilson&#39;s ideas about the operator product expansion at short distances and reveals an intricate interplay of subtle features of the theory such as heavy quark masses in Glashow-Iliopoulos-Maini cancellation,

Fredrik Ståhl

The b-boundary construction by B. Schmidt is a general way of providing a boundary to a manifold with connection. It has been shown to have undesirable topological properties however. C. J. S. Clarke gave a result showing that for space-times, non-Hausdorffness is to be expected in general, but the argument contains some errors. We show that under somewhat d

Yuriy Yu. Tarasevich, Steven C. van der Marck

A calculation of site-bond percolation thresholds in many lattices in two to five dimensions is presented. The line of threshold values has been parametrized in the literature, but we show here that there are strong deviations from the known approximate equations. We propose an alternative parametrization that lies much closer to the numerical values

Maya Paczuski, Per Bak

The basic laws of physics are simple, so why is the world complex? The theory of self-organized criticality posits that complex behavior in nature emerges from the dynamics of extended, dissipative systems that evolve through a sequence of meta-stable states into a critical state, with long range spatial and temporal correlations. Minor disturbances lead to

H. Nojiri, K. Kaneko, M. Motokawa, K. Hirota

It was discovered in La1-xSrxMnO3(x~1/8) that a field induced phase transition occurs from a ferromagnetic metal(FM) phase to a ferromagnetic insulator (FI) phase. The magnetization shows a sharp jump at the transition field accompanying with a remarkable increase of magnetoresistance. Striction measurements clarified that this transition is associated with

H. Nojiri, H. Ohta, S. Okubo, O. Fujita

Transitions between the ground singlet state to the excited triplet state has been observed in CuGeO3 by means of submillimeter wave electron spin resonance. The strong absorption intensity shows the break down of the selection rule. The energy gap at zero field is evaluated to be 570 GHz(2.36 meV) and this value is nearly identical to the gap at the zone ce

H Nojiri, H. Kageyama, Kenzo Onizuka, Y. Ueda

Various spin gap excitations have been observed in the two-dimensional dimer system SrCu_2(BO_3)_2 by means of submillimeter wave ESR. The zero-field energy gap of the lowest spin gap excitation shows a splitting into two triplet modes and the energy splitting clearly depends on the magnetic field orientation when a field is rotated in the {\mib {ac}}-plane.

R. Gatt, S. Christensen, B. Frazer, Y. Hirai

We have used angular resolved photoemission to measure the angular dependence of the superconducting gap in highly overdoped Bi2212 (Tc=65K). While the node at 45 degrees is conserved, we find substantial deviation from a first order d-wave dependence away from the node. The pairing susceptibility is peaked at special regions on the Fermi surface. Comparing