October 2002 arXiv papers — page 14

Li-Xin Li, Jeremy Goodman, Ramesh Narayan

It has been suggested that quasi-periodic oscillations of accreting X-ray sources may relate to the modes named in the title. We consider non-axisymmetric linear perturbations to an isentropic, isothermal, unmagnetized thin accretion disk. The radial wave equation, in which the number of vertical nodes (n) appears as a separation constant, admits a wave-acti

Yuval Grossman, Howard E. Haber

In lepton-number-violating supersymmetric models, there is no natural choice of basis to distinguish the down-type Higgs and lepton superfields. We employ basis-independent techniques to identify the massless majoron and associated light scalar in the case of spontaneously-broken lepton number (L). When explicit L-violation is added, these two scalars can ac

Avishai Dekel, Joanna Woo

We study in simple terms the role of feedback in establishing the scaling relations of low-surface-brightness and dwarf galaxies with stellar masses in the range 6x10^5 <M*< 3x10^10 Msun. These galaxies, as measured from SDSS and in the Local Group, show tight correlations of internal velocity, metallicity and surface brightness (or radius) with M*. They def

Andrey A. Elistratov, Denis Yu. Vodolazov, Igor L. Maksimov, John R. Clem

Recent theoretical and experimental research on low-bulk-pinning superconducting strips has revealed striking dome-like magnetic-field distributions due to geometrical edge barriers. The observed magnetic-flux profiles differ strongly from those in strips in which bulk pinning is dominant. In this paper we theoretically describe the current and field distrib

Yu-ichiro Ezoe, Naoko Iyomoto, Kazuo Makishima, Gunter Hasinger

An improved method is utilized to estimate the X-ray power spectral densities (PSD) and the variation time scales of three quasars in the Lockman Hole field. Five archival ROSAT PSPC data covering two year range are analyzed. To estimate PSD from sparse and unevenly-sampled lightcurves, a forward-method approach with extensive Monte-Carlo simulations is adop

Robert H. Brandenberger

Due to the quasi-exponential red-shifting which occurs during an inflationary period in the very early Universe, wavelengths which at the present time correspond to cosmological lengths are in general sub-Planckian during the early stages of inflation. This talk discusses two approaches to addressing this issue which both indicate that the standard predictio

D. J. Mikkelson, R. L. Mikkelson, T. G. Worlton, A. Chatterjee

The overall design of the Integrated Spectral Analysis Workbench (ISAW), being developed at Argonne, provides for an extensible, highly interactive, collaborating set of viewers for neutron scattering data. Large arbitrary collections of spectra from multiple detectors can be viewed as an image, a scrolled list of individual graphs, or using a 3D representat

Jian-Miin Liu

The Coulomb barrier is in general much higher than thermal energy. Nuclear fusion reactions occur only among few protons and nuclei with higher relative energies than Coulomb barrier. It is the equilibrium velocity distribution of these high-energy protons and nuclei that participates in determining the rate of nuclear fusion reactions. In the circumstance i

F. Meissner

We report the first observation of coherent rho0 production (AuAu->AuAu rho0) and rho0 production accompanied by mutual nuclear Coulomb excitation (AuAu->Au*Au*rho0),and the observation of coherent e+e- pair production (AuAu->Au*Au*e+e-) in ultra-peripheral relativistic heavy-ion collisions (UPCs). We give transverse momentum, mass, and rapidity distribution

Alberto S. Cattaneo, Carlo A. Rossi

An observable for nonabelian, higher-dimensional forms is introduced, its properties are discussed and its expectation value in BF theory is described. This is shown to produce potential and genuine invariants of higher-dimensional knots.

Yu Chen, Matthew Dyer

It is shown that there is an order isomorphism $ϕ&#39;$ from the poset $V$ of $B\times B$-orbits on the wonderful compactification of a semi-simple adjoint group $G$ with Weyl group $W$ to an interval in reverse Chevalley-Bruhat order on a non-canonically associated Coxeter group $\hat{W}$ (in general neither finite nor affine). Moreover, $ϕ&#39;$ preserves

Jens Wirth

The aim of this short note is to reconsider and to extend a former result of K. Mochizuki on the existence of the scattering operator for wave equations with small dissipative terms. Contrary to the approach used by Mochizuki we construct the wave operator explicitly in terms of the parametrix construction obtained by a (simplified) diagonalization procedure

Hugh R. Morton

The Murphy operators in the Hecke algebra H_n of type A are explicit commuting elements, whose symmetric functions are central in H_n. In [Skein theory and the Murphy operators, J. Knot Theory Ramif. 11 (2002), 475-492] I defined geometrically a homomorphism from the Homfly skein C of the annulus to the centre of each algebra H_n, and found an element P_m in

Jose J. Blanco-Pillado, Martin Bucher

We comment on the global structure of the spacetime that results from the collision of two bubbles filled with AdS space produced from the decay of a false vacuum through quantum tunnelling.

Jan Naudts, Maciej Kuna, Wojciech De Roeck

We present a model of interacting quantum fields, formulated in a non-perturbative manner. One of the fields is treated semi-classically, the other is the photon field. The model has an interpretation of an electromagnetic field in a fluctuating spacetime. The model is equivalent with the quantization of electromagnetism proposed recently by Czachor. Interes

M. R. Setare

In this paper we discuss the question of whether the entropy of cosmological horizon in Topological Reissner-Nordström- de Sitter spaces can be described by the Cardy-Verlinde formula, which is supposed to be an entropy formula of conformal field theory in any dimension. Furthermore, we find that the entropy of black hole horizon can also be rewritten in ter

E. P. Likhtman

In this paper I developed a classical model of elementary particle that is associated with a membrane of finite size, surrounded by non-linear electromagnetic field. The form of local interaction which lead to bounded states of finite masses, charges and spins was constructed. To do this I added Kaluza-Klein Lagrangian on the surface, which is associated wit

R. L. Mkrtchyan

The little groups (i.e. the subgroups of Lorentz group, leaving invariant given configurations of tensorial charges) of unitary irreps of superstring/M-theory superalgebras are considered. It is noted, that in the case of $(n-1)/n$ (maximal supersymmetric) BPS configuration in any dimensions the non-zero supercharge is neutral w.r.t. the algebra of little gr

Roland E. Allen

An action with unconventional supersymmetry was introduced in an earlier paper. Here it is shown that this action leads to standard physics for fermions and gauge bosons at low energy, but to testable extensions of standard physics for fermions at high energy and for fundamental bosons which have not yet been observed. For example, the Lorentz-violating equa

Jerzy Matyjasek

Employing the approximate effective action constructed from the coincidence limit of the Hadamard-Minakshisundaram-DeWitt (HaMiDeW) coefficient a_{3}, the renormalized stress-energy tensor of the quantized massive scalar field in the spacetime of a static and electrically charged dilatonic black hole is calculated. Special attention is paid to the minimally

L. Raul Abramo, Leon Brenig, Edgard Gunzig, Alberto Saa

We investigate the robustness of some recent results obtained for homogeneous and isotropic cosmological models with conformally coupled scalar fields. For this purpose, we investigate anisotropic homogeneous solutions of the models described by the action $$ S=\int d^4x \sqrt{-g}\left\{F(ϕ)R - \partial_aϕ\partial^aϕ-2V(ϕ) \right\}, $$ with general $F(ϕ)$ an

Joern Beckmann, Peter Link, Tobias Unruh, Nils Pyka

The NeXus format allows the storage of measured data next to a description of sample and instrument setup in a standardized manner. The NeXus standard itself gives only general rules how an instrument setup is described. A so called instrument definition contains a minimal set of information and the location of that information within a file. In this paper i

Shi-Jian Gu, You-Quan Li

In this paper, we study the magnetic properties of the one-dimensional SU(4) spin-orbital model by solving its Bethe ansatz solution numerically. It is found that the magnetic properties of the system for the case of $g_t=1.0$ differs from that for the case of $g_t=0.0$. The magnetization curve and susceptibility are obtained for a system of 200 sites. For $

Zoltan Racz

Nonequilibrium phase transitions are discussed with emphasis on general features such as the role of detailed balance violation in generating effective (long-range) interactions, the importance of dynamical anisotropies, the connection between various mechanisms generating power-law correlations, and the emergence of universal distribution functions for macr

J. A. James, J. R. Santistiban, M. R. Daymond, L. Edwards

The new generation of dedicated Engineering Strain Scanners at neutron facilities such as ENGIN-X at ISIS and SMARTS at LANSCE offer considerable increases in both the throughput of samples and the density of measurements which are feasible within each sample. This trend is set to increase further with new neutron sources such as the SNS. In order to make fu

C Li, J J Wang, C Y He, L F Meng

The distribution of the current density and the profile of the trapped magnetic field of a superconducting disk magnetized by uniform field are calculated from first principles. The effect of the superconducting parameters is taken into account by assuming the voltage-current law and the material law. The sample volume, the critical current density and the f

Jens Krueger

At present each neutron scattering facility has its own set of data treatment software, normally based on a proprietary data format. The travelling scientist is either forced to continually learn new software or to write conversion routines for his own software tools. During software development most of the time is spent on routines connected with file input

Jens Krueger, Juergen Neuhaus

With the start up of the new German Neutron Source FRM-II in Garching, a common instrument control system has to be installed at the different neutron scattering instruments. With respect to the large variety of instruments, a modular system was required. In spite of starting from scratch, a well developed and tested system was needed, in order to meet the r

Chang Yoke Ling, C. K. Ong

Simultaneous studies on the magnetic and electrotransport properties of Nd_{0.67} Sr_{0.33} Mn_{1-x} Fe_x O_3 polycrystalline bulk and epitaxial thin films (x = 0.00 and 0.05) have been carried out. A magnetoresistance (MR) as high as ~ 33% is observed for Nd_{0.67} Sr_{0.33} MnO_3 bulk at the metal-insulator transition (MIT) temperature (T_p) of 273 K in a

Bianxiao Cui, Haim Diamant, Binhua Lin

We study experimentally and theoretically the hydrodynamic coupling between Brownian colloidal particles diffusing along a linear channel. The quasi-one-dimensional confinement, unlike other constrained geometries, leads to a sharply screened interaction. Consequently, particles move in concert only when their mutual distance is smaller than the channel widt

J. R. Hoerandel

The knee in the all-particle energy spectrum is scrutinized with a phenomenological model, named poly-gonato model, linking results from direct and indirect measurements. For this purpose, recent results from direct and indirect measurements of cosmic rays in the energy range from 10 GeV up to 1 EeV are examined. The energy spectra of individual elements, as

T. Elperin, N. Kleeorin, I. Rogachevskii, S. Zilitinkevich

A new mean-field theory of turbulent convection is developed. This theory predicts the convective wind instability in a shear-free turbulent convection which causes formation of large-scale semi-organized fluid motions in the form of cells or rolls. Spatial characteristics of these motions, such as the minimum size of the growing perturbations and the size o

T. Hamana, S. Miyazaki, K. Shimasaku, H. Furusawa

We present measurements of the cosmic shear correlation in the shapes of galaxies in the Suprime-Cam 2.1 deg^2 R_c-band imaging data. As an estimator of the shear correlation originated from the gravitational lensing, we adopt the aperture mass variance. We detect a non-zero E mode variance on scales between 2 and 40arcmin. We also detect a small but non-zer

Jeremy Butterfield

This paper discusses some of the modal involvements of analytical mechanics. I first review the elementary aspects of the Lagrangian, Hamiltonian and Hamilton-Jacobi approaches. I then discuss two modal involvements; both are related to David Lewis&#39; work on modality, especially on counterfactuals. The first is the way Hamilton-Jacobi theory uses ensemble

Tsung-Wen Yeh

This paper has been withdrawn by the author due to new results to be added.

Reinhard Genzel, Andrew J. Baker, Linda J. Tacconi, Dieter Lutz

We report high-resolution millimeter mapping with the IRAM Plateau de Bure interferometer of rest-frame 335 micron continuum and CO(3-2) line emission from the z=2.8 submillimeter galaxy SMMJ02399-0136. The continuum emission comes from a ~3&#34; diameter structure whose elongation is approximately east-west and whose centroid is coincident within the astrom

Paolo Muratore-Ginanneschi

In 1967 M.C. Gutzwiller succeeded to derive the semiclassical expression of the quantum energy density of systems exhibiting a chaotic Hamiltonian dynamics in the classical limit. The result is known as the Gutzwiller trace formula. The scope of this review is to present in a self-contained way recent developments in functional determinant theory allowing to

M. K. Parida, B. Purkayastha, C. R. Das, B. D. Cajee

In a class of SUSY SO(10) with $SU(2)_L x SU(2)_R x U(1)_{B-L} x SU(3)_C$ $(g_{2L}\neq g_{2R})$ intermediate gauge symmetry, we observe that the prediction on the unification mass $(M_U)$ is unaffected by Planck-scale-induced gravitational and intermediate-scale-threshold effects, although the intermediate scale $(M_I)$ itself is subject to such corrections.

C. Wildfeuer, D. H. Schiller

We describe a mathematical solution for the generation of entangled N-photon states in two field modes. A simple and compact solution is presented for a two-mode Jaynes-Cummings model by combining the two field modes in a way that only one of the two resulting quasi-modes enters in the interaction term. The formalism developed is then applied to calculate va

Lorenzo Iorio

In this paper the most recent developments in testing General Relativity in the gravitational field of the Earth with the technique of Satellite Laser Ranging are presented. In particular, we concentrate our attention on some gravitoelectric and gravitomagnetic post--Newtonian orbital effects on the motion of a test body in the external field of a central ma

M. G. Raymer, A. C. Funk, B. C. Sanders, H. de Guise

Entanglement, or quantum inseparability, is a crucial resource in quantum information applications, and therefore the experimental generation of separated yet entangled systems is of paramount importance. Experimental demonstrations of inseparability with light are not uncommon, but such demonstrations in physically well-separated massive systems, such as di

V. S. Prasanna Rajan, K. C. James Raju

The use of covariant projection finite elements in the efficient 3-D vector finite element analysis of wave guide is presented.

V. S. Prasanna Rajan, K. C. James Raju

The divergence condition is reformulated in the scaled boundary coordinates so as to prevent the spurious solutions in the finite element formulation.

V. S. Prasanna Rajan, K. C. James Raju

A Novel Scaled boundary finite element method, initially developed in Civil Engineering, is reformulated for solving boundary value problems in computational electromagnetics.

Andrei Derevianko, Sergey G. Porsev, Svetlana Kotochigova, Eite Tiesinga

Ultra-cold collisions of spin-polarized 24Mg,40Ca, and 88Sr in the metastable 3P2 excited state are investigated. We calculate the long-range interaction potentials and estimate the scattering length and the collisional loss rate as a function of magnetic field. The estimates are based on molecular potentials between 3P2 alkaline-earth atoms obtained from ab

Ilya Kapovich, Paul Schupp

We apply the method of Arzhantseva-Ol&#39;shanskii to prove that for an exponentially generic (in the sense of Ol&#39;shanskii) class of one-relator groups the isomorphism problem is solvable in at most exponential time. This is obtained as a corollary of our more general result that for any fixed integers $m>1, n>0$ there is an exponentially generic class o

I. Hoveijn, J. S. W. Lamb, R. M. Roberts

In this article we classify normal forms and unfoldings of linear maps in eigenspaces of (anti)-automorphisms of order two. Our main motivation is provided by applications to linear systems of ordinary differential equations, general and Hamiltonian, which have both time-preserving and time-reversing symmetries. However the theory gives a uniform method to o

Yuri A. Rylov

It is shown that scalar product of two vectors can be introduced in any geometry (metric space) independently of possibility of the linear space introduction. In general, linear properties of scalar product are restricted. Domain of linearity increases in homogeneous geometry.

Ilya Kapovich, Richard Weidmann

We obtain a number of finiteness results for groups acting on Gromov-hyperbolic spaces. In particular we show that a torsion-free locally quasiconvex hyperbolic group has only finitely many conjugacy classes of $n$-generated one-ended subgroups. We also show that the rank problem is solvable for the class of torsion-free locally quasiconvex hyperbolic groups

J. J. van der Bij, Eugen Radu

We argue that there are no axially symmetric rotating monopole solutions for a Yang-Mills-Higgs theory in flat spacetime background. We construct axially symmetric Yang-Mills-Higgs solutions in the presence of a negative cosmological constant, carrying magnetic charge $n$ and a nonvanishing electric charge. However, these solution are also nonrotating.

Sudarshan Ananth

We study bosonic strings in a Rindler background using a D-23 brane. This model is shown to be directly related to the orbifold approach to Rindler strings. We propose a duality between these pictures based on comparisons of their closed string spectra.

Kingman Cheung

In models of large extra dimensions, the string and Planck scales become accessible at future colliders. When the energy scale is above the string scale or Planck scale a number of interesting phenomena occur, namely, production of stringy states, $p$-branes, string balls, black hole, etc. In this Proceedings, we summarize a recent work \cite{me0} on the pro

Yu. S. Vladimirov, S. S. Kokarev

4-dimensional homogeneous isotropic cosmological models obtained from solutions of vacuum 5-dimensional Einstein equations are considered. It is assumed, that the G(55)-component of the 5-d metric simulates matter in the comoving frame of reference. Observable 4-d metric is defined up to conformal transformations of the metric of 4-d section \tilde{g}, with

Asher Peres

Recent observations of the fine structure of spectral lines in the early universe have been interpreted as a variation of the fine structure constant. From the assumed validity of Maxwell equations in general relativity and well known experimental facts, it is proved that $e$ and $\hbar$ are absolute constants. On the other hand, the speed of light need not

Anastasios Mallios, Ioannis Raptis

We continue recent work and formulate the gravitational vacuum Einstein equations over a locally finite spacetime by using the basic axiomatics, techniques, ideas and working philosophy of Abstract Differential Geometry. The whole construction is `fully covariant&#39;, `inherently quantum&#39; (both expressions are analytically explained in the paper) and ge

Anastasios Mallios

We present herewith certain thoughts on the important subject of nowadays physics, pertaining to the so-called ``singularities&#39;&#39;, that emanated from looking at the theme in terms of ADG (: abstract differential geometry). Thus, according to the latter perspective, we can involve ``singularities&#39;&#39; in our arguments, while still employing fundam

Petros Maniatis, Mary Baker

People change the identifiers through which they are reachable online as they change jobs or residences or Internet service providers. This kind of personal mobility makes reaching people online error-prone. As people move, they do not always know who or what has cached their now obsolete identifiers so as to inform them of the move. Use of these old identif

T. G. Worlton, A. Chatterjee, J. P. Hammonds, P. F. Peterson

New generations of neutron scattering sources and instrumentation are providing challenges in data handling for user software. Time-of-Flight instruments used at pulsed sources typically produce hundreds or thousands of channels of data for each detector segment. New instruments are being designed with thousands to hundreds of thousands of detector segments.

Zhen Ye

It has been the dominant view for over two decades that all waves are localized in two dimensions for any given amount of disorder. Here, I would like to raise questions about this assertion. The discussion leads to the conclusion that there is a lack of the conclusive and definite support of the claim. Rather, the recent evidence tends to indicate that wave

P. F. Peterson, D. J. Mikkelson, R. L. Mikkelson, A. J. Schultz

Software for time-of-flight single crystal diffractometer (SCD) data visualization and analysis was originally written to be run in batch mode on VMS-VAX systems. Modern computers and software tools allow a new level of visualization and user interaction. The Integrated Spectral Analysis Workbench (ISAW) is being extended and customized for SCD measurements.

K. C. Ku, S. J. Potashnik, R. F. Wang, M. J. Seong

We report Curie temperatures up to 150 K in annealed Ga1-xMnxAs epilayers grown with a relatively low As:Ga beam equivalent pressure ratio. A variety of measurements (magnetization, Hall effect, magnetic circular dichroism and Raman scattering) show that the higher ferromagnetic transition temperature results from an enhanced free hole density. The data also

P. F. Peterson, Th. Proffen, R. L. Mikkelson, T. Kozlowski

NeXus is an international standard data format intended to reduce the need for redundant software development efforts in the neutron and x-ray scattering communities. As the NeXus standard matures it is starting to be used at laboratories for storing raw data. The Manuel Lujan Jr. Neutron Scattering Center (MLNSC) at Los Alamos National Laboratory and the In

D. K. K. Lee, S. Rapsch, J. T. Chalker

We study quantum Hall ferromagnets in the presence of a random electrostatic impurity potential, within the framework of a classical non-linear sigma model. We discuss the behaviour of the system using a heuristic picture for the competition between exchange and screening, and test our conclusions with extensive numerical simulations. We obtain a phase diagr

Henry C. Fu

In this paper we perform a renormalization group analysis on the 1+1 dimensional version of an effective field theory (previously proposed by Dung-Hai Lee, cond-mat/011393) describing (quantum) fluctuating stripe and superconductor orders. We find four possible phases corresponding to stripe order/disorder combined with superconducting order/disorder.

Dariusz Graczyk, Maciej Mikolajewski, Laurits Leedjarv, Sylwia M. Frackowiak

We report Johnson&#39;s UBVRI photometric and optical spectroscopic observations of a long period variable HP Lyr which up to now has been considered an eclipsing binary with a period of 140 days. The spectral type changes continually from A2-3 at maxima to A7-F2 at minima. We propose that the brightness changes are caused by the pulsation of the star with t

Sylwia M. Frackowiak, Maciej Mikolajewski, Toma Tomov

MWC 560 and other peculiar symbiotic binary, CH Cyg, have been classified as the prototypes of the new subclass of symbiotic systems - propellers, with accretion onto a magnetic white dwarf being the source of activity. The companion of the hot component in this model should demonstrate stellar wind with relatively high mass-loss. It can be expected rather a

Mirek Giersz, Douglas C. Heggie

We construct a simple dynamical model of the massive globular cluster Omega Cen. The model includes simple treatments of dynamical evolution in a galactic tide, and evolution of single stars. Binary stars and rotation are neglected. The model approximately fits observational data on the surface brightness profile, the profile of radial velocity dispersion, a

F. Rosati

Results of a general study on the dynamics of cosmological scalar fields with arbitrary potentials are presented. Exact and approximate attractor solutions are found, with applications to quintessence, moduli stabilization and inflation.

G. Papavassiliou, M. Belesi, M. Fardis, M. Pissas

55Mn and 139La NMR measurements on a high quality single crystal of ferromagnetic (FM) La0.80Ca20MnO3 demonstrate the formation of localized Mn(3+,4+) states below 70 K, accompanied with strong anomalous increase of certain FM neutron Bragg peaks. (55,139)(1/T1) spin-lattice relaxation rates diverge on approaching this temperature from below, signalling a ge

I. Vekhter, A. V. Shytov, I. A. Gruzberg, A. V. Balatsky

We analyse the behavior of the density of states in a singlet s-wave superconductor with weak magnetic impurities in the clean limit by using the method of optimal fluctuation. We show that the density of states varies as $\ln N(E)\propto -|E-Δ_0|^{(7-d)/4}$ near the mean field gap edge $Δ_0$ in a d-dimensional superconductor. The optimal fluctuation in d>1

Matthew Gursky, Jeff Viaclovsky

We consider the problem of conformally deforming a metric to one with a prescribed symmetric function of the eigenvalues of the Ricci tensor, in the case of negative curvature.

Etera R. Livine, Daniele Oriti

We analyse the classical and quantum geometry of the Barrett-Crane spin foam model for four dimensional quantum gravity, explaining why it has to be considering as a covariant realization of the projector operator onto physical quantum gravity states. We discuss how causality requirements can be consistently implemented in this framework, and construct causa

Matthew Gursky, Jeff Viaclovsky

In this paper we study the problem of finding a conformal metric with the property that the k-th elementary symmetric polynomial of the eigenvalues of its Weyl-Schouten tensor is constant. A new conformal invariant involving maximal volumes is defined, and this invariant is then used in several cases to prove existence of a solution, and compactness of the s

David Berenstein

In this paper we show that the matrix model techniques developed by Dijkgraaf and Vafa can be extended to compute quantum deformed moduli spaces of vacua in four dimensional supersymmetric gauge theories. The examples studied give the moduli space of a bulk D-brane probe in geometrically engineered theories, in the presence of fractional branes at singularit

Barbara Kraus, Klemens Hammerer, Geza Giedke, J. Ignacio Cirac

Several recent experiments have demonstrated the promise of atomic ensembles for quantum teleportation and quantum memory. In these cases the collective internal state of the atoms is well described by continuous variables $X_1, P_1$ and the interaction with the optical field ($X_2, P_2$) by a quadratic Hamiltonian $X_1X_2$. We show how this interaction can

Jean-Luc Thiffeault

The statistics of polymers advected by a turbulent flow are investigated. To limit the polymer lengths above to coil-stretch transition, a FENE-P type relaxation law is used. The turbulence is modeled by a random strain, delta-correlated in time and with Gaussian statistics. The distribution of polymer lengths for both the coiled and stretched states are der

E. G. Novik, H. Buhmann, L. W. Molenkamp

A quantum mechanical model based on a Green&#39;s function approach has been used to calculate the transmission probability of electrons traversing a two-dimensional electron gas injected and detected via mode-selective quantum point contacts. Two-dimensional scattering potentials, back-scattering, and temperature effects were included in order to compare th

T. Duguet, P. Bonche

This paper deals with the theoretical foundation of effective two-body forces for the Generator Coordinate Method (GCM) and the projected mean-field method. The first aim of this paper is to reduce into various local-densities the in-medium content of a generalized $G$ matrix removing the hard core problem in this extended context. Then, we consider the poss

Graham Brightwell, H. Fay Dowker, Raquel S. Garcia, Joe Henson

The ``generic&#39;&#39; family of classical sequential growth dynamics for causal sets provides cosmological models of causal sets which are a testing ground for ideas about the, as yet unknown, quantum theory. In particular we can investigate how general covariance manifests itself and address the problem of identifying and interpreting covariant ``observab

Arjan Keurentjes

Dimensional reduction of (super-)gravity theories to 3 dimensions results in sigma models on coset spaces G/H, such as the E_8/SO(16) coset in the bosonic sector of 3 dimensional maximal supergravity. The reverse process, oxidation, is the reconstruction of a higher dimensional gravity theory from a coset sigma model. Using the group G as starting point, the

Jun Ushida, Masatoshi Tokushima, Masayuki Shirane, Hirohito Yamada

We present a systematic method for designing a perfect antireflection coating (ARC) for a semi-infinite one-dimensional (1D) photonic crystal (PC) with an arbitrary unit cell. We use Bloch wave expansion and time reversal symmetry, which leads exactly to analytic formulas of structural parameters for the ARC and renormalized Fresnel coefficients of the PC. S

Vladimir Kadets, Nigel Kalton, Dirk Werner

We investigate rich subspaces of $L_1$ and deduce an interpolation property of Sidon sets. We also present examples of rich separable subspaces of nonseparable Banach spaces and we study the Daugavet property of tensor products.

J. -R. Chazottes, P. Collet

For a large class of expanding maps of the interval, we prove that partial sums of Lipschitz observables satisfy an almost sure central limit theorem (ASCLT). In fact, we provide a speed of convergence in the Kantorovich metric. Maxima of partial sums are also shown to obey an ASCLT. The key-tool is an exponential inequality recently obtained. Then we derive

M. Hasenbusch, K. Jansen

We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of systems with dynamical fermions to two flavor QCD with clover-improvement. For our smallest quark masses we see a speed-up of more than a factor of two compared with the standard algorithm.

M. L. Mangano, M. Moretti, F. Piccinini, R. Pittau

We present a study of the Higgs production at the LHC via Weak Boson Fusion, with the Higgs boson decaying into a b-quark pair. A detailed partonic LO calculation of all the potential backgrounds is performed. We conclude that this channel for Higgs production can be extracted from the backgrounds, and present our estimates of the accuracy in the determinati

O. Guehne, P. Hyllus, D. Bruss, A. Ekert

In this paper we address the problem of detection of entanglement using only few local measurements when some knowledge about the state is given. The idea is based on an optimized decomposition of witness operators into local operators. We discuss two possible ways of optimizing this local decomposition. We present several analytical results and estimates fo

Shoji Yamamoto, Hiromitsu Hori

Modifying the conventional antiferromagnetic spin-wave theory which is plagued by the difficulty of the zero-field sublattice magnetizations diverging in one dimension, we describe magnetic properties of Haldane-gap antiferromagnets. The modified spin waves, constituting a grand canonical bosonic ensemble so as to recover the sublattice symmetry, not only de

Sayan Kar, Soumitra SenGupta, Saurabh Sur

Static, spherically symmetric solutions of the Einstein--Kalb--Ramond (KR) field equations are obtained. Besides an earlier known exact solution, we also find an approximate, asymptotically flat solution for which the metric coefficients are obtained as an infinte series in $\frac{1}{r}$. Subsequently, we study gravitational lensing and perihelion precession

Hui Zhai, WeiQiang Chen, Zhan Xu, Lee Chang

We study the properties of coreless vortices(skyrmion) in spinor Bose-Einstein condensate. We find that this excitation is always energetically unstable, it always decays to an uniform spin texture. We obtain the skyrmion energy as a function of its size and position, a key quantity in understanding the decay process. We also point out that the decay rate of

Rajsekhar Bhattacharyya, Debashis Gangopadhyay

The spacetime dependent lagrangian formalism of references [1-2] is used to obtain is used to obtain a classical solution of Yang-Mills theory. This is then used to obtain an estimate of the vacuum expectation value of the Higgs field,{\it viz.} $ϕ_{a}=A/e$, where $A$ is a constant and $e$ is the Yang-Mills coupling (related to the usual electric charge).The

F. J. Petriello

We present a calculation of the complete $O(α)$ electroweak radiative corrections to the Moller scattering process e^-e^- -> e^-e^-, including hard bremsstrahlung contributions. We study the effects of these corrections on both the total cross section and polarization asymmetry measured in low energy fixed target experiments. Numerical results are presented

Biman B. Nath

We study steady, homogeneous and subsonic cooling flows in poor clusters of galaxies in light of the recent proposal that radiative cooling of the intracluster gas can explain the observations of the `entropy floor&#39; and other related X-ray observations. We study a family of cooling flow solutions parameterized by the mass flux rate, and then determine th

Joachim Ankerhold, Markus Saltzer

Quantum mechanical real-time tunneling through general scattering potentials is studied in the semiclassical limit. It is shown that the exact path integral of the real-time propagator is dominated in the long time sector by quasi-stationary fluctuations associated with caustics. This leads to an extended semiclassical propagation scheme for wave packet dyna

S. B. Leble, S. Yalunin

A dressing of a nonspherical potential, which includes $n$ zero range potentials, is considered. The dressing technique is used to improve ZRP model. Concepts of the partial waves and partial phases for non-spherical potential are used in order to perform Darboux transformation. The problem of scattering on the regular $\hbox{X}_n$ and $\hbox{YX}_n$ structur

Jietai Jing, Jing Zhang, Ying Yan, Fagang Zhao

A tripartite entangled state of bright optical field is experimentally produced using an Einstein-Podolsky-Rosen entangled state for continuous variables and linear optics. The controlled dense coding among a sender, a receiver and a controller is demonstrated by exploiting the tripartite entanglement. The obtained three-mode position correlation and relativ

An Min Wang

We propose a sufficient and necessary separability criterion for pure states in multipartite and high dimensional systems. Its main advantage is operational and computable. The obvious expressions of this criterion can be given out by the coefficients of components of the pure state. In the end, we simply mention a principle method how to define and obtain t

J. P. Hammonds, R. R. Porter, A. Chatterjee, T. G. Worlton

The Intense Pulsed Neutron Source has been an operating user facility for more than 20 years. Development of an upgrade for the data acquisition system has been in progress for some time now. Now that the initial installation on the test bed instrument (HRMECS) is completed new features and possibilities are starting to come forward. Run setup is moving from

Nivaldo A. Lemos

Making use of the theory of infinitesimal canonical transformations, a concise proof is given of Jacobi&#39;s identity for Poisson brackets.

Victor I. Kopp, Azriel Z. Genack

We demonstrate that twisting one part of a chiral photonic structure about its helical axis produces a single circularly polarized localized mode that gives rise to an anomalous crossover in propagation. Up to a crossover thickness, this defect results in a peak in transmission and exponential scaling of the linewidth for a circularly polarized wave with the

Mark Koennecke, Uwe Filges

NeXus is a joint effort of both the synchrotron and neutron scattering community to devlop a common data exchange format based on HDF. In order to simplify access to NeXus-files a NeXus-API is provided. This NeXus-API has been redesigned and expanded to cover both HDF versions 4 and 5. Only small changes to the API were necessary in order to accomplish. A ne