March 2001 arXiv papers — page 4

Mario A. Castagnino, Jorge Gueron, Adolfo Ordoniez

When $t\to \infty $ any wave packet in the liouvillian representation of the density matrices, becomes a Hardy class function from below. This fact, in the global frame of Reichenbach diagram, is used to explain the observed global time asymmetry of the universe.

Martin Hairer

We study stochastic partial differential equations of the reaction-diffusion type. We show that, even if the forcing is very degenerate (i.e. has not full rank), one has exponential convergence towards the invariant measure. The convergence takes place in the topology induced by a weighted variation norm and uses a kind of (uniform) Doeblin condition.

A. G. Ramm

Let $D\subset \R^n$, $n\geq 3,$ be a bounded domain with a $C^{\infty}$ boundary $S$, $L=-\nabla^2+q(x)$ be a selfadjoint operator defined in $H=L^2(D)$ by the Neumann boundary condition, $θ(x,y,λ)$ be its spectral function, $θ(x,y,λ):=\ds\sum_{λ_j<λ} ϕ_j(x)ϕ$ where $Lϕ_j=λ_jϕ_j$, $ϕ_{j N}|_S=0,$ $\|ϕ_j\|_{L^2(D)}=1$, $j=1,2,...$. The potential $q(x)$ is a r

Victor G. Kac

Talk given at the conference &#34;Visions in Mathematics toward the year 2000&#34;, August 1999, Tel-Aviv.

Guillaume Jamet

We show that any hyperplane section of a variety which is the inverse image of a smooth variety of dimension at least 2 by an endomorphism (wich is not an automorphism) of the projective space, is linearly complete. We stress the case of smooth surfaces in projective fourspace.

William Arveson, Geoffrey Price

A spin system is a sequence of self-adjoint unitary operators $U_1,U_2,...$ acting on a Hilbert space $H$ which either commute or anticommute, $U_iU_j=\pm U_jU_i$ for all $i,j$; it is is called irreducible when $\{U_1,U_2,...\}$ is an irreducible set of operators. There is a unique infinite matrix $(c_{ij})$ with $0,1$ entries satisfying $$ U_iU_j=(-1)^{c_{i

Michael H. Freedman, Michael J. Larsen, Zhenghan Wang

Introduction 1. The two-eigenvalue problem 2. Hecke algebra representations of braid groups 3. Duality of Jones-Wenzl representations 4. Closed images of Jones-Wenzl sectors 5. Distribution of evaluations of Jones polynomials 6. Fibonacci representations

Edward Aboufadel, Amanda Cox, Amy Vander Zee

Using the Daubechies conditions of compact support, orthogonal, and regularity, we were able to derive bivariate scaling functions with which to reproduce linear functions (planes). We describe how to create all possible masks of refinement coefficients that satisfy those conditions.

Juan C. Migliore, Uwe Nagel

An SI-sequence is a finite sequence of positive integers which is symmetric, unimodal and satisfies a certain growth condition. These are known to correspond precisely to the possible Hilbert functions of Artinian Gorenstein algebras with the Weak Lefschetz Property, a property shared by most Artinian Gorenstein algebras. Starting with an arbitrary SI-sequen

Raphael Hauser, Osman Guler

Self-scaled barrier functions on self-scaled cones were introduced through a set of axioms in 1994 by Y.E. Nesterov and M.J. Todd as a tool for the construction of long-step interior point algorithms. This paper provides firm foundation for these objects by exhibiting their symmetry properties, their intimate ties with the symmetry groups of their domains of

M. Teicher, T. Ben-Itzhak

In this paper we prove certain Hurwitz equivalence properties in $B_n$. Our main result is that every two Artin&#39;s factorizations of $Δ_n ^2$ of the form $H_{i_1} ... H_{i_{n(n-1)}}, \quad F_{j_1} ... F_{j_{n(n-1)}}$ (with $i_k, j_k \in \{1,...,n-1 \}$), where $\{H_1,...,H_{n-1} \}, \{F_1,...,F_{n-1} \}$ are frames, are Hurwitz equivalent. This theorem is

P. F. Kelly, Terry Pilling

We adopt an empirical approach to the characterization of the distribution of twin primes within the set of primes, rather than in the set of all natural numbers. The occurrences of twin primes in any finite sequence of primes are like fixed probability random events. As the sequence of primes grows, the probability decreases as the reciprocal of the count o

Andrei Caldararu

We construct an equivalence between the derived category of sheaves on an elliptic threefold without a section and a derived category of twisted sheaves (modules over an Azumaya algebra) on any small resolution of its relative Jacobian.

Katherine M. Benson

Spontaneous breaking of global symmetries can produce ``Alice&#39;&#39; strings: line defects which make unbroken symmetries multivalued, induce apparent charge violation via Aharonov-Bohm interactions, and form point defects when twisted into loops. We demonstrate this behavior for both divergent and textured global Alice strings. Both adiabatically scatter

Ian. I Kogan, Alex Kovner, Martin Schvellinger

We study the behaviour of Polyakov confining string in the Georgi-Glashow model in three dimensions near confining-deconfining phase transition described in hep-th/0010201. In the string language, the transition mechanism is the decay of the confining string into D0 branes (charged W bosons of the Georgi-Glashow model). In the world-sheet picture the world-l

A. V. Gulov, V. V. Skalozub

New observables for searching for Z&#39; virtual states in processes e^+e^-\to\bar{f}f are proposed. They are based on the relations following due to renormalizability of an underlying theory between the parameters of the low-energy effective Lagrangian. Two types of the Z&#39; interactions are considered. The observables allow to pick up uniquely the signal

Fábio L. Braghin, Fernando S. Navarra

A time dependent variational approach is used to derive the equations of motion for the λϕ^4 model. The simultaneous evolution of the quantum fluctuations and of the classical part of the field is considered in a lattice of 1+1 dimensions. Different initial conditions corresponding to non equilibrium situations are considered and evolved in time. Such high e

K. Werner, H. J. Drescher, S. Ostapchenko, T. Pierog

We outline inconsistencies in presently used models for high energy nuclear scattering, which make their application quite unreliable. Many &#34;successes&#34; are essentially based on an artificial freedom of parameters, which does not exist when the models are constructed properly. The problem is the fact that any multiple scattering theory requires an app

K. Werner, H. J. Drescher, S. Ostapchenko, T. Pierog

We discuss the current understanding of nuclear scattering at very high energies. We point out several serious inconsistencies in nowadays models, which provide big problems for any interpretation of data at high energy nuclear collisions. We outline how to develop a fully self-consistent formalism, which in addition uses all the knowledge available from stu

Martin Freund

The corrections to neutrino mixing parameters in the presence of matter of constant density are calculated systematically as series expansions in terms of the mass hierarchy $\dm{21}/\dm{31}$. The parameter mapping obtained is then used to find simple, but nevertheless accurate formulas for oscillation probabibilities in matter including CP-effects. Expressi

M. Genovese, C. Novero, E. Predazzi

We discuss if experimental tests of Bell inequalities performed with pseudoscalar mesons (K or B) can be definitive. Our conclusion is that this is not the case, for the efficiency loophole cannot be eliminated.

J. M. Cline, U. A. Yajnik

Randall and Sundrum have proposed that we live on a brane embedded in 5-dimensional anti-deSitter space, as a solution to the hierarchy problem. We examine the possibility of using a scalar field in the 5-D bulk as the inflaton, and show that it gives results which are indistinguishable from an inflaton which is restricted to our brane. This makes it difficu

A. D. Martin

An attempt is made to summarize the discussion at the Workshop, except for the panel discussion on the ability of the LHC detectors to accommodate forward reactions. The Workshop focused on two main topics. The first topic was forward physics at the LHC. Predictions were made for forward reactions, including elastic scattering and soft diffractive processes,

Munshi G. Mustafa, Markus H. Thoma

The implications of a numerical error in the photon production rate on the direct photon spectrum of a chemically non-equilibrated quark-gluon plasma are discussed.

Stephan Elser

We investigate various variants of the Hermitean version of the Local Bosonic Algorithm proposed by M. Lüscher. The model used is two-dimensional Quantum Electrodynamics (QED) with two flavours of massive Wilson fermions. The simplicity of the model allows high statistics simulations close to the chiral and continuum limit. To find optimal CPU cost behaviour

P. Petreczky with O. Kaczmarek, F. Karsch, E. Laermann, S. Stickan

We investigate medium effects in QCD like chromoelectric screening and quasi-particle mass generation by calculating the heavy quark potential as well as the temporal quark and gluon Coulomb gauge propagators in quenched approximation.

C. Bozzi

Recent BaBar measurements on lifetime and mixing of B mesons are reported. Various techniques are used, ranging from the full reconstruction of hadronic B decays, to partial reconstruction techniques, and to a totally inclusive approach with dilepton events. The results presented are based on a data sample collected by BaBar during the 1999-2000 data taking,

O. Lalakulich, L. Marochnik, G. Vereshkov

A gauge-independent, invariant theory of linear scalar perturbations of inflation and gravitational fields has been created. This invariant theory allows one to compare gauges used in the work of other researchers and to find the unambiguous criteria to separate the physical and coordinate effects. It is shown, in particular, that the so-called longitudial g

Amir H. Abbassi

Space-time is spherically symmetric if it admits the group of SO(3) as a group of isometries,with the group orbits spacelike two-surfaces. These orbits are necessarily two-surface of constant positive curavture. One commonly chooses coordinate ${t,r,θ,ϕ}$ so that the group orbits become surfaces ${t,r = const.}$ and the radial coordinate r is defined by the

Alan D. Rendall, Marsha Weaver

In numerical studies of Gowdy spacetimes evidence has been found for the development of localized features (spikes) involving large gradients near the singularity. The rigorous mathematical results available up to now did not cover this kind of situation. In this work we show the existence of large classes of Gowdy spacetimes exhibiting features of the kind

Greg Sepesi

An algorithm is presented that efficiently solves the selection problem: finding the k-th smallest member of a set. Relevant to a divide-and-conquer strategy, the algorithm also partitions a set into small and large valued subsets. Applied recursively, this partitioning results in a sorted set. The algorithm&#39;s applicability is therefore much broader than

Bill Allcock, Joe Bester, John Bresnahan, Ann L. Chervenak

An emerging class of data-intensive applications involve the geographically dispersed extraction of complex scientific information from very large collections of measured or computed data. Such applications arise, for example, in experimental physics, where the data in question is generated by accelerators, and in simulation science, where the data is genera

Marc Ruehlaender, Peter Markos, C. M. Soukoulis

We investigate the probability distribution $p(g)$ of the conductance $g$ in anisotropic two-dimensional systems. The scaling procedure applicable to mapping the conductance distributions of localized anisotropic systems to the corresponding isotropic one can be extended to systems at the critical point of the metal-to-insulator transition. Instead of the sq

T. A. Callcott, L. Lin, G. T. Woods, G. P. Zhang

Soft X-ray absorption and fluorescence measurements are reported for the K-edge of B in MgB2. The measurements confirm a high density of B pxy(sigma)-states at the Fermi edge and extending to approximately 0.9 eV above the edge. A strong resonance is observed in elastic scattering through a core-exciton derived from out-of-plane pz(pi*)-states. Another stron

N. Lemke, Jeferson J. Arenzon, Yan Levin

We present a simple model to study micellization of amphiphiles condensed on a rodlike polyion. Although the mean field theory leads to a first order micellization transition for sufficiently strong hydrophobic interactions, the simulations show that no such thermodynamic phase transition exists. Instead, the correlations between the condensed amphiphiles ca

Anna Minguzzi, Gabriele Ferrari, Yvan Castin

We describe the excitation spectrum of a two-component neutral Fermi gas in the superfluid phase at finite temperature by deriving a suitable Random-Phase approximation with the technique of functional derivatives. The obtained spectrum for the homogeneous gas at small wavevectors contains the Bogoliubov-Anderson phonon and is essentially different from the

Juergen F. Stilck, Yan Levin, Jeferson J. Arenzon

We study the thermodynamic properties of a simple model for the possible mechanism of attraction between like charged rodlike polyions inside a polyelectrolyte solution. We consider two polyions in parallel planes, with $Z$ charges each, in a solution containing multivalent counterions of valence $α$. The model is solved exactly for $Z \le 13$ for a general

M. Pohlt, M. Lynass, J. G. S. Lok, W. Dietsche

Separately contacted double layers of a 2d electron - 2d hole gases have been prepared in GaAs separated by thin AlGaAs barriers with thicknesses down to 15 nm. The molecular-beam-epitaxial growth was interrupted just before the barrier in order to use in situ focussed-ion-beam implantation to pattern contacts which extend underneath the barrier. The two cha

A. S. Arnold, C. MacCormick, M. G. Boshier

We report the reflection and focussing of a Bose-Einstein condensate by a new pulsed magnetic mirror. The mirror is adaptive, inelastic, and of extremely high optical quality. The deviations from specularity are less than 0.5 mrad rms, making this the best atomic mirror demonstrated to date. We have also used the mirror to realize the analog of a beam-expand

Hans-Karl Janssen, Olaf Stenull

The relationship between vulcanization and percolation is explored from the perspective of renormalized local field theory. We show rigorously that the vulcanization and percolation correlation functions are governed by the same Gell--Mann-Low renormalization group equation. Hence, all scaling aspects of the vulcanization transition are reigned by the critic

C. Fusco, P. Gallo, A. Petri, M. Rovere

We have performed extensive simulations of random sequential adsorption and diffusion of $k$-mers, up to $k=5$ in two dimensions with particular attention to the case $k=2$. We focus on the behavior of the coverage and of vacancy dynamics as a function of time. We observe that for $k=2,3$ a complete coverage of the lattice is never reached, because of the ex

A. Sharoni, G. Koren, O. Millo

Tunneling spectra measured on thin epitaxial YBa2Cu3O7-delta films are found to exhibit strong spatial variations, showing U and V-shaped gaps as well as zero bias conductance peaks typical of a d-wave superconductor. A full correspondence is found between the tunneling spectra and the surface morphology down to a level of a unit-cell step. Splitting of the

Giorgio Favrin, Anders Irbäck, Fredrik Sjunnesson

We develop a new elementary move for simulations of polymer chains in torsion angle space. The method is flexible and easy to implement. Tentative updates are drawn from a (conformation-dependent) Gaussian distribution that favors approximately local deformations of the chain. The degree of bias is controlled by a parameter b. The method is tested on a reduc

Nurit Avraham, Boris Khaykovich, Yuri Myasoedov, Michael Rappaport

Inverse melting, in which a crystal reversibly transforms into a liquid or amorphous phase upon decreasing the temperature, is considered to be very rare in nature. The search for such an unusual equilibrium phenomenon is often hampered by the formation of nonequilibrium states which conceal the thermodynamic phase transition, or by intermediate phases, as w

G. Kharadze, N. Suramlishvili

The spin-orbital configurations of the coherently precessing spin modes characterized by a small value of the magnetization $(M\ll M_{0}=χH_{0})$ is considered. Various regimes are analysed depending on the transverse rf-field strength

R. Ahluwalia, G. Ananthakrishna

We devise a two dimensional model that mimics the recently observed power law distributions for the amplitudes and durations of the acoustic emission signals observed during martensitic transformation [ Vives {\it et al}, Phys. Rev. Lett. {\bf 72}, 1694 (1994)]. We include a threshold mechanism arising from the athermal nature of transformation, long-range i

Giulio Bottazzi

The paper presents an analysis performed over the worldwide top 150 firms in the pharmaceutical industry. It begins with a test of the Gibrat&#39;s Law of Proportionate Effect finding, in line with previous literature, a violation concerning the variance of the growth. Then it shows, using disaggregated data on sub-markets (defined according to the ATC code)

D. A. Dikin, M. J. Black, V. Chandrasekhar

We report measurements of the magnetoresistance (MR) of narrow Au wires coupled to a superconducting Al contact on one end, and a normal Au contact on the other. The MR at low magnetic field $B$ is quadratic in $B$, with a characteristic field scale $B_c$ determined by phase coherent paths which encompass not only the wire, but also the two contacts. $B_c$ i

M. D. Grynberg

A set of one dimensional interfaces involving attachment and detachment of $k$-particle neighbors is studied numerically using both large scale simulations and finite size scaling analysis. A labeling algorithm introduced by Barma and Dhar in related spin Hamiltonians enables to characterize the asymptotic behavior of the interface width according to the ini

Hector G. Arce, Alyssa A. Goodman

We present the first set of detailed molecular line maps of the region associated with the giant Herbig-Haro flow HH 300, from the young star IRAS 04239+2436. Our results indicate that the red lobe of the HH 300 flow is depositing a fair amount of momentum and kinetic energy over a notable volume of its host dark cloud. This makes HH 300 a key player in the

J. E. Carlstrom, M. Joy, L. Grego, G. Holder

The Sunyaev-Zel&#39;dovich effect (SZE) provides a powerful tool for cosmological studies. Through recent advances in instrumentation and observational techniques it is now possible to obtain high quality measurements of the effect toward galaxy clusters. The analysis of the SZE toward a few tens of clusters has already led to interesting constraints on the

K. Flint, M. Bolte, C. Mendes de Oliveira

We present first results of a survey of the Leo I group at 10 Mpc for M_R < -10 dwarf galaxies. This is part of a larger program to measure the faint end of the galaxy luminosity function in nearby poor groups. Our method is optimized to find Local-Group-like dwarfs down to dwarf spheroidal surface brightnesses, but we also find very large LSB dwarfs in Leo

Thorsten Naab, Andreas Burkert

We investigate detailed kinematical properties of simulated collisionless merger remnants of disk galaxies with mass ratios of 1:1 and 3:1. The simulations were performed by direct summation using the new special hardware device GRAPE-5. In agreement with observations, the shape of the line-of-sight velocity distribution (LOSVD) is Gaussian with small deviat

S. Covino, M. R. Panzera, G. Tagliaferri, R. Pallavicini

We discuss ROSAT and ASCA observations of the young active star Gl355}. During the ROSAT observation a strong flare was detected with a peak flux more than an order of magnitude larger than the quiescent level. Spectral analysis of the data allows us to study the temperature and emission measure distribution, and the coronal metal abundance, for the quiescen

I. W. Roxburgh, A. G. Polnarev, G. Giampieri, S. V. Vorontsov

We investigate the possibility of observing very small amplitude low frequency solar oscillations with the proposed laser interferometer space antenna LISA. For frequencies below $\sim 2\times 10^{-4}$ Hz the dominant contribution is from the near zone time dependent gravitational quadrupole moments associated with the normal modes of oscillation. For freque

Henny J. G. L. M. Lamers, Antonella Nota, Nino Panagia, Linda J. Smith

We use the analysis of the heavy element abundances (C, N, O, S) in circumstellar nebulae around Luminous Blue Variables to infer the evolutionary phase in which the material has been ejected. (1) We discuss the different effects that may have changed the gas composition of the nebula since it was ejected (2) We calculate the expected abundance changes at th

C. Hanhart

A procedure to derive bounds on coupling strengths of exotic particles to nucleons from the neutrino signal of supernovae is outlined. The analysis is based on a model independent calculation for the emissivities for the exotic, detailed simulation for the evolution of the early proto-neutron star as well as a Likelihood analysis. As an example we derive con

Rashid Sunyaev

Accreting black holes and neutron stars at luminosities above 0.01 of the critical Eddington luminosity have a lot of similarities, but also drastic differences in their radiation and power density spectra. The efficiency of energy release due to accretion onto a rotating neutron star usually is higher than in the case of a black hole. The theory of the spre

G. Ghisellini, D. Lazzati, S. Covino, .

While all but one Gamma-Ray Bursts observed in the X-ray band showed an X-ray afterglow, about 60 per cent of them have not been detected in the optical band. We show that this is not due to adverse observing conditions. We then investigate the hypothesis that the failure of detecting the optical afterglow is due to absorption at the source location. We find

Dalia Chakrabarty, Prasenjit Saha

We estimate the mass of the central black hole in our Galaxy from stellar kinematical data published by Ghez et al. (1998) and Genzel et al. (2000). For this we develop a method, related to Merritt (1993), for non-parametrically reconstructing the mass profile and the stellar distribution function in the central region of the Galaxy from discrete kinematic d

F. Munyaneza, R. D. Viollier

After a discussion of the properties of degenerate fermion balls, we analyze the orbits of the stars S0-1 and S0-2, which have the smallest projected distances to Sgr A*, in the supermassive black hole as well as in the fermion ball scenarios of the Galactic center. It is shown that both scenarios are consistent with the data, as measured during the last six

Matthias Bartelmann, Lindsay King, Peter Schneider

Integral measures of weak gravitational lensing by dark-matter haloes, like the aperture mass, are sensitive to different physical halo properties dependent on the halo mass density profile. For isothermal profiles, the relation between aperture mass and virial mass is steeper than for haloes with the universal NFW profile. Consequently, the halo mass range

Duncan A. Forbes, Antonis E. Georgakakis, Jean P. Brodie

The presence of two globular cluster subpopulations in early-type galaxies is now the norm rather than the exception. Here we present two more examples for which the host galaxy appears to have undergone a recent merger. Using multi-colour Keck imaging of NGC 1052 and NGC 7332 we find evidence for a bimodal globular cluster colour distribution in both galaxi

Sun Hong Rhie

Gravitational lensing can be by a faint star, a trillion stars of a galaxy, or a cluster of galaxies, and this poses a familiar struggle between particle method and mean field method. In a bottom-up approach, a puzzle has been laid on whether a quadruple lens can produce 17 images. The number of images is governed by the gravitational lens equation, and the

Andrew Sheinis

We present off-nuclear spectra of 3 radio loud QSO&#39;s, 3C249.1, 3C273 and 3C323.1., taken with the echellette spectrograph and imager (ESI) at Keck observatory. From these spectra we have extracted the spatial profile along the slit of the [OIII], $λ= \textsf{5007}$ line. Fitted Gaussian distributions to each of these profiles show emission-line gas out t

David W. Koerner

The imaging of disks around young stars presents extreme challenges in high dynamic range, angular resolution, and sensitivity. Recent instrumental advances have met these challenges admirably, leading to a marked increase in imaging discoveries. These have opened up a new era in studies of the origin of planetary systems. Questions about our own solar syste

Cheongho Han

Gould & DePoy proposed a pixel lensing survey towards the Galactic bulge using a small aperture (~65 mm) camera with a large pixel size (10&#34;) detector and deliberately degraded optics achieving 30&#34; PSF. In this paper, we estimate the event rate of this pixel lensing survey expected under various detection criteria, which are characterized by the thre

V. V. Shokurov

The main result of the paper is a boundedness for $n$-complements on algebraic surfaces. In addition, applications of this theorem to a classification of log Del Pezzo surfaces and of birational contractions for 3-folds are formulated.

Zi-wei Lin, C. M. Ko

We show that $ω_B$ or $ω_{\bar B}$, the squared baryon or antibaryon number fluctuation per baryon or antibaryon, is a possible signature for the quark-gluon plasma that is expected to be created in relativistic heavy ion collisions, as it is a factor of three smaller than in an equilibrated hadronic matter due to the fractional baryon number of quarks. Usin

F. Larios, G. Tavares-Velasco, C. -P. Yuan

We show that a general two-Higgs-doublet model (THDM) with a very light CP-odd scalar (A) can be compatible with the rho parameter, Br(b --> sγ), R_b, A_b, (g-2) of muon, Br(Upsilon --> A gamma), and the direct search via the Yukawa process at LEP. For its mass around 0.2 GeV, the muon (g-2) and Br(Upsilon --> A γ) data require tan(beta) to be about 1. Conse

B. Grossan, V. Gorjian, M. Werner, M. Ressler

We observed two nearby galaxies with potential or weak indications of nuclear activity, M32 and M81, with the MIRLIN mid-IR camera at N band (10.79 microns). M32 is not detected, but we give detailed measurements of the nucleus of M81. Our observations of M81 show a bright nuclear point source at N, and comparison to measurements made in the early 1970&#39;s

Howard Baer, Csaba Balazs, Javier Ferrandis, Xerxes Tata

The recent measurement of a_μ=\frac{g_μ-2}{2} by the E821 Collaboration at Brookhaven deviates from the quoted Standard Model (SM) central value prediction by 2.6σ. The difference between SM theory and experiment may be easily accounted for in a variety of particle physics models employing weak scale supersymmetry (SUSY). Other supersymmetric models are dist

Mikhail Khovanov

We construct a family of rings. To a plane diagram of a tangle we associate a complex of bimodules over these rings. Chain homotopy equivalence class of this complex is an invariant of the tangle. On the level of Grothendieck groups this invariant descends to the Kauffman bracket of the tangle. When the tangle is a link, the invariant specializes to the bigr

S. Carlip

Several recent approaches to black hole entropy obtain the density of states from the central charge of a Liouville theory. If Liouville theory is coupled to a dynamical spacetime background, however, the classical central charge vanishes. I show that the central charge can be restored by introducing appropriate constraints, which may be interpreted as fall-

Terry Rudolph, Barry C. Sanders

We show that the sender (Alice) and the receiver (Bob) each require coherent devices in order to achieve unconditional continuous variable quantum teleportation (CVQT), and this requirement cannot be achieved with conventional laser sources, even in principle. The appearance of successful CVQT in recent experiments is due to interpreting the measurement reco

Jason Pruet, George M. Fuller, Christian Y. Cardall

We study steady state winds from compact objects in the regime where the wind velocity at infinity is ultra-relativistic. This may have relevance to some models of Gamma-Ray-Bursts (GRB&#39;s). Particular attention is paid to the case where neutrinos provide the heating. Unless the neutrino luminosity is very large, L>10^{54} erg/s, the only allowed steady s

G. Grassano, W. Ramadan, V. Ferrando, E. Bellingeri

Superconducting thin films of MgB2 were deposited by Pulsed Laser Deposition on magnesium oxide and sapphire substrates. Samples grown at 450C in an argon buffer pressure of about 10-2 mbar by using a magnesium enriched target resulted to be superconducting with a transition temperature of about 25 K. Film deposited from a MgB2 sintered pellet target in ultr

Henry Cohn, Robin Pemantle, James Propp

A sink-free orientation of a finite undirected graph is a choice of orientation for each edge such that every vertex has out-degree at least 1. Bubley and Dyer (1997) use Markov Chain Monte Carlo to sample approximately from the uniform distribution on sink-free orientations in time O(m^3 log (1/epsilon)), where m is the number of edges and epsilon the degre

D. Kaczorowski, A. J. Zaleski, O. J. Żogał, J. Klamut

Magnetic properties of TaB$_{2}$ were studied by means of DC and AC susceptibility measurements. It has been found that the compound becomes superconducting at T$_{c}$ = 9.5 K. From upper critical field measurements the superconducting parameters have been evaluated, which indicated that TaB$_{2}$ is a hard type-II superconductor. Possible reasons why superc

G. Arutyunov, B. Eden, A. C. Petkou, E. Sokatchev

We show that certain classes of apparently unprotected operators in N=4 SYM_4 do not receive quantum corrections as a consequence of a partial non-renormalization theorem for the 4-point function of chiral primary operators. We develop techniques yielding the asymptotic expansion of the 4-point function of CPOs up to order O(λ^2) and we perform a detailed OP

E. Capelas de Oliveira, W. A. Rodrigues, D. S. Thober, A. L. Xavier

In this paper we present thoughtful comments on the paper `Bessel beams and signal propagation&#39; showing that the main claims of that paper are wrong. Moreover, we take the opportunity to show the non trivial and indeed surprising result that a scalar pulse (i.e., a wave train of compact support in the time domain) that is solution of the homogeneous wave

Xuelei Chen, Marc Kamionkowski, Xinmin Zhang

After neutralinos cease annihilating in the early Universe, they may still scatter elastically from other particles in the primordial plasma. At some point in time, however, they will eventually stop scattering. We calculate the cross sections for neutralino elastic scattering from standard-model particles to determine the time at which this kinetic decoupli

T. Karpiuk, M. Brewczyk, K. Rzazewski

We investigate the possibilities of generation of solitons and vortices in a degenerate gas of neutral fermionic atoms. In analogy with, already experimentally demonstrated, technique applied to gaseous Bose-Einstein condensate we propose the phase engineering of a Fermi gas as a practical route to excited states with solitons and vortices. We stress that so

G. Grasso, A. Malagoli, C. Ferdeghini, S. Roncallo

The Powder-In-Tube process has been employed to fabricate tape-like conductors with a strong metallic sheath and based on the newly discovered MgB2 superconducting phase. Long superconducting tapes have been prepared by packing reacted MgB2 powders inside pure Ag, Cu and Ni tubes which are then cold worked by drawing and rolling. Such tapes have shown transp

Louisa A. Nolan, James S. Dunlop, Raul Jimenez, Alan F. Heavens

We explore whether the rest-frame near-UV spectral region, observable in high-redshift galaxies via optical spectroscopy, contains sufficient information to allow the degeneracy between age and metallicity to be lifted. We do this by testing the ability of evolutionary synthesis models to reclaim the correct metallicity when fitted to the near-UV spectra of

O. F. Dayi, A. Jellal

We consider the behavior of electrons in an external uniform magnetic field B where the space coordinates perpendicular to B are taken as noncommuting. This results in a generalization of standard thermodynamics. Calculating the susceptibility, we find that the usual Landau diamagnetism is modified. We also compute the susceptibility according to the nonexte

Michael Truss, James Murray, Graham Wynn

We present the first detailed hydrodynamic simulation of a superoutburst to incorporate the full tidal potential of a binary system. A two-dimensional smoothed particle hydrodynamics code is used to simulate a superoutburst in a binary with the parameters of the SU UMa system Z Chamaeleontis. The simulated light curves shows all the features observed in such

Vassily Plyaskin

A calculation of the fluxes of primary particles arriving to the Earth&#39;s vicinity as well as those produced in the interactions of the primaries with the atmosphere is presented. The result of calculations is compared with the experimental data obtained with the Alpha Magnetic Spectrometer (AMS). A good agreement of calculated and measured fluxes of char

Gordon Chalmers

We examine the form of the cosmological constant in the loop expansion of broken maximally supersymmetric supergravity theories, and after embedding, within superstring and M-theory. Supersymmetry breaking at the TeV scale generates values of the cosmological constant that are in agreement with current astrophysical data. The form of perturbative quantum eff

Jens O. Andersen

QED is studied at low temperature ($T\ll m$, where $m$ is the electron mass) and zero chemical potential. By integrating out the electron field and the nonzero bosonic Matsubara modes, we construct an effective three-dimensional field theory that is valid at distances $R\gg1/T$. As applications, we reproduce the ring-improved free energy and calculate the De

Daniel C. Homan, Joanne M. Attridge, John F. C. Wardle

We present circular polarization results from a 5 GHz survey of the parsec-scale polarization properties of 40 AGN made with the VLBA. We find 11 circular polarization detections at the 3 sigma level or higher. This nearly quadruples the number of sources detected in circular polarization at VLBI resolution. We find no correlation between fractional linear a

S. Y. Choi, M. Drees, B. Gaissmaier, Jae Sik Lee

We discuss in detail signals for CP violation in the Higgs boson and tau-slepton sectors through the production processes $μ^+μ^- \to \tildeτ_i^- \tildeτ_j^+$, where $i,j=1,2$ label the two $τ$ slepton mass eigenstates in the minimal supersymmetric standard model. We assume that the soft breaking parameters of third generation sfermions contain CP violating

G. Amelino-Camelia, J. Lukierski, A. Nowicki

We consider the process of collision between a hard photon and a soft photon producing an electron-positron pair, under the assumption that the kinematics be described according to the $κ$-deformation of the D=4 Poincaré algebra. We emphasize the relevance of this analysis for the understanding of the puzzling observations of multi-TeV photons from Markarian

R. Fossion, C. De Coster, J. E. Garcia-Ramos, T. Werner

Nuclear binding energies and two-neutron separation energies are analyzed starting from the liquid-drop model and the nuclear shell model in order to describe the global trends of the above observables. We subsequently concentrate on the Interacting Boson Model (IBM) and discuss a new method in order to provide a consistent description of both, ground-state

Asher Peres, Petra F. Scudo

A single quantum system, such as a hydrogen atom, can transmit a Cartesian coordinate frame (three axes). For this it has to be prepared in a superposition of states belonging to different irreducible representations of the rotation group. The algorithm for decoding such a state is presented, and the fidelity of transmission is evaluated.

D. Gromes

We decompose the quark propagator in the presence of an arbitrary gluon field with respect to a set of Dirac matrices. The four-dimensional integrals which arise in first order perturbation theory are rewritten as line-integrals along certain field lines, together with a weighted integration over the various field lines. It is then easy to transform the prop

T. E. Humphrey, H. Linke, R. Newbury

We describe how adiabatically rocked quantum electron ratchets can act as heat pumps. In general, ratchets may be described as non-equilibrium systems in which directed particle motion is generated using spatial or temporal asymmetry. In a rocked ratchet, which may also be described as a non-linear rectifier, an asymmetric potential is tilted symmetrically a

Zhe Chang, Xin-Bing Huang

We calculate the vacuum energy density by taking account of different massive scalar fields in AdS spacetime. It is found that the mass spectrum of a scalar field in AdS spacetime is discrete because of a natural boundary condition. The results match well with the observed cosmological constant.

Jae Dong Noh, Hyunggyu Park, Doochul Kim, Marcel den Nijs

The scaling properties of a random walker subject to the global constraint that it needs to visit each site an even number of times are determined. Such walks are realized in the equilibrium state of one dimensional surfaces that are subject to dissociative dimer-type surface dynamics. Moreover, they can be mapped onto unconstrained random walks on a random

Hitoshi Nishino, Subhash Rajpoot

By analyzing eleven-dimensional superspace fourth-rank superfield strength F-Bianchi identities, we show that M-theory corrections to eleven-dimensional supergravity can not be embedded into the mass dimension zero constraints, such as the (\g^{a b})_{\a\b} X_{a b}{}^c or i (\g^{a_1... a_5})_{\a\b} X_{a_1... a_5}{}^c -terms in the supertorsion constraint T_{