August 2001 arXiv papers — page 17

Hans-Christian v. Bothmer

Based on a recent result of Voisin [2001] we describe the last nonzero syzygy space in the linear strand of a canonical curve C of even genus g=2k lying on a K3 surface, as the ambient space of a k-2-uple embedded P^{k+1}. Furthermore the geometric syzygies constructed by Green and Lazarsfeld [1984] from g^1_{k+1}'s form a non degenerate configuration of

R. M. Green

We study the combinatorics of fully commutative elements in Coxeter groups of type $H_n$ for any $n > 2$. Using the results, we construct certain canonical bases (i.e., IC bases) for non-simply-laced generalized Temperley--Lieb algebras and show how to relate them to morphisms in the category of decorated tangles.

Jozef H. Przytycki

We give a description of the growth of research on Knot Theory in Japan. We place our report in a general historical context. In particular, we compare the development of research on mathematical topology in Japan with that in Poland and USA, observing several similarities. Toward the end of XIX century and at the beginning of XX century several young mathem

William Crawley-Boevey

We prove that the Marsden-Weinstein reductions for the moment map associated to representations of a quiver are normal varieties. We give an application to conjugacy classes of matrices.

D. G. C. McKeon, T. N. Sherry

The simplest supersymmetry algebra and superspace in three dimensional Euclidean (3dE) space is examined. Representations of the algebra are considered and the implications of restricting the space of states to states with positive definite norm are determined. A superspace is defined and superfields are introduced. Supersymmetric field theory models in 3dE

Sunil Mukhi

A boundary-state computation is performed to obtain derivative corrections to the Chern-Simons coupling between a p-brane and the RR gauge potential C(p-3). We work to quadratic order in the gauge field strength F, but all orders in derivatives. In a certain limit, which requires the presence of a constant B-field background, it is found that these correctio

J. Balog, A. Hegedus

We study the free energy of the 1+1 dimensional O(N) nonlinear sigma-models for even N using the TBA equations proposed recently. We give explicit formulae for the constant solution of the TBA equations (Y-system) and calculate the first two virial coefficients. The free energy is also compared to the leading large N result.

K. Juenemann, Bernd Spendig

The amplitudes for emission and scattering of N=2 strings off D-branes are calculated. We consider in detail the amplitudes <cc> and <occ> for the different types of D-branes. For some D-branes we find massive poles in the scattering spectrum that are absent in the ordinary N=2 spectrum.

H. van Dam, Y. Jack Ng

Why does the physical 4-dimensional space have a 3 + 1 signature rather than a 4 + 0 or a 2 + 2 for its metric? We give a simple explanation based largely on a group-theoretic argument a la Wigner. Applied to flat spaces of higher dimensions the same approach indicates that metrics with more than one time dimension are physically unacceptable because the cor

D. L. Henty

An alternative approach to introducing gravitational dynamics on a brane embedded in a higher dimensional spacetime is presented. The brane is treated as a boundary of a higher dimensional manifold in which the bulk action is described by a metric independent topological quantum field theory. The example of a five dimensional non-Abelian BF theory with a bou

Edi Halyo

We show that the entropy of de Sitter space in any dimension can be understood as the entropy of a highly excited string located near the horizon. The string tension is renormalized to $T \sim Λ$ due to the large gravitational redshift near the horizon. The de Sitter temperature is given by the Hagedorn temperature of the string.

Sunil Mukhi, Nemani V Suryanarayana

We obtain the couplings of noncommutative branes of type II string theories to constant Ramond-Ramond backgrounds, for BPS as well as non-BPS branes, in the background-independent description. For the BPS branes, we also generalize these couplings to other descriptions, and thereby argue their equivalence to the known couplings in the commutative description

Matthias Neubert, Alexey A. Petrov

Recent experimental results on the color-suppressed nonleptonic decays B^0 -> D^{(*)0} pi^0 provide evidence for a failure of the naive factorization model and for sizeable relative strong-interaction phases between class-1 and class-2 B -> D^(*) pi decay amplitudes. The allowed regions for the corresponding ratios of (complex) isospin amplitudes and a_2/a_1

R. Contino, L. Pilo, R. Rattazzi, E. Trincherini

We study 5 dimensional grand-unified theories in an orbifold geometry by the method of effective field theory: we match the low and high energy theories by integrating out at 1-loop the massive Kaluza-Klein states. In the supersymmetric case the radius dependence of threshold effects is fixed by the rescaling anomalies of the low energy theory. We focus on a

Pavel Nadolsky

I discuss the impact of the the coherent parton radiation on semi-inclusive production of hadrons in deep inelastic scattering at lepton-proton colliders. Such radiation can be consistently described in the $b$-space resummation formalism, which was originally developed to improve theoretical description of production of hadrons at $e^+e^-$ colliders and ele

B. C. Allanach, C. M. Harris, M. A. Parker, P. Richardson

New almost-degenerate charged and neutral heavy leptons are a feature of a number of theories of physics beyond the Standard Model. The prospects for detecting these at the Large Hadron Collider using a time-of-flight technique are considered, along with any cosmological or experimental constraints on their masses. Based on a discovery criterion of 10 detect

K. J. Eskola, V. J. Kolhinen, P. V. Ruuskanen, R. L. Thews

We compute cross sections for the Drell-Yan process in nuclear collisions at next-to-leading order (NLO) in α_s. The effects of shadowing on the normalization and on the mass and rapidity dependence of these cross sections are presented. An estimate of higher order corrections is obtained from next-to-next-to-leading order (NNLO) calculation of the rapidity-

R. Arnowitt, B. Dutta, B. Hu, Y. Santoso

The effect of the recently observed 2.6 sigma deviation of the muon anomalous magnetic moment (a_mu = (g_mu -2)/2) from its Standard Model prediction is examined within the framework of supergravity models with grand unification and R parity invariance. The constraints of the Higgs mass bounds, the b -> s gamma bounds (including the large tan beta NLO correc

Nora Brambilla

I discuss effective field theories for heavy bound systems, particularly bound systems involving two heavy quarks. The emphasis is on the relevant concepts and on interesting physical applications and results.

I. Montvay

The Monte Carlo simulation of Majorana fermions is discussed on the example of supersymmetric Yang-Mills (SYM) theory.

S. A. Dytman

We present a search for the ``wrong-sign&#39;&#39; decay D0 -> K+ pi- pi+ pi- using 9 fb-1 of e+e- collisions on and just below the Upsilon(4S) resonance. This decay can occur either through a doubly Cabibbo-suppressed process or through mixing to a D0bar followed by a Cabibbo-favored process. Our result for the time-integrated wrong-sign rate relative to th

J. C. Hart, for ZEUS Collaboration, H1 Collaboration

A recent analysis of prompt-photon events in ZEUS has led to a new determination of the effective transverse parton momentum in the proton. The observation of deeply virtual Compton scattering by ZEUS and H1, including a first measurement of the DVCS cross section at HERA by H1, is also reported.

H. Jeong, B. Kahng, S. Lee, C. Y. Kwak

The fabrication of ZnSe/ZnTe superlattices grown by the process of rotating the substrate in the presence of an inhomogeneous flux distribution instead of successively closing and opening of source shutters is studied via Monte Carlo simulations. It is found that the concentration of each compound is sinusoidally modulated along the growth direction, caused

Stephan C. Kramer, Reiner Kree

A model of mobile, charged ion channels in a fluid membrane is studied. The channels may switch between an open and a closed state according to a simple two-state kinetics with constant rates. The effective electrophoretic charge and the diffusion constant of the channels may be different in the closed and in the open state. The system is modeled by densitie

Petr Jizba, Toshihico Arimitsu

We discuss a basic thermodynamic properties of systems with multifractal structure. This is possible by extending the notion of Gibbs-Shannon&#39;s entropy into more general framework - Renyi&#39;s information entropy. We show a connection of Renyi&#39;s parameter q with the multifractal singularity spectrum f(α) and clarify a relationship with the Tsallis-H

A. A. Chabanov, M. Stoytchev, A. Z. Genack

The realization that electron localization in disordered systems (Anderson localization) is ultimately a wave phenomenon has led to the suggestion that photons could be similarly localized by disorder. This conjecture attracted wide interest because the differences between photons and electrons - in their interactions, spin statistics, and methods of injecti

S. M. Girvin

I review recent novel experimental and theoretical advances in the physics of quantum Hall effect bilayers. Of particular interest is a broken symmetry state which optimizes correlations by putting the electrons into a coherent superposition of the two different layers.

P. Vargas, D. Altbir, M. Knobel, D. Laroze

A two dimensional magnetic particle in the presence of an external magnetic field is studied. Equilibrium thermodynamical properties are derived by evaluating analytically the partition function. When the external field is applied perpendicular to the anisotropy axis the system exhibits a second order phase transition with order parameter being the magnetiza

D. J. Singh, M. Gupta, R. Gupta

Density functional calculations are used to study magnetic and electronic properties of the spinel ferrites, ZnFe$_2$O$_4$ and MnFe$_2$O$_4$. Correct magnetic orderings are obtained. ZnFe$_2$O$_4$ is predicted to be a small gap insulator in agreement with experiment. MnFe$_2$O$_4$ is found to be a low carrier density half-metal in the fully ordered state. Ho

Paul E. Lammert, Vincent H. Crespi, Angel Rubio

Carbon nanotubes are one-dimensional and very narrow. These obvious facts imply that under doping with boron and nitrogen, microscopic doping inhomogeneity is much more important than for bulk semiconductors. We consider the possibility of exploiting such fluctuations to create interesting devices. Using self-consistent tight-binding (SCTB), we study heavily

N. Bulut

The Knight shift data on Li and Zn substituted YBa$_2$Cu$_3$O$_{6+x}$ are analysed using an itinerant model with short-range antiferromagnetic correlations. The model parameters, which are determined by fitting the experimental data on the transverse nuclear relaxation rate $T_2^{-1}$ of pure YBa$_2$Cu$_3$O$_{6+x}$, are used to calculate the Knight shifts fo

M. J. Qin, X. L. Wang, H. K. Liu, S. X. Shi

The magnetic field dependent critical current density $j_c(B)$ of a MgB$_2$ bulk sample has been obtained by means of magnetization hysteresis measurements. The $j_c(B)$ curves at different temperatures demonstrate a crossover from single vortex pinning to small-bundle vortex pinning, when the field is larger than the crossover field $B_{sb}$. The temperatur

N. R. Thomas, C. J. Foot, A. C. Wilson

We present a magnetic trapping scheme for neutral atoms based on a hybrid of Ioffe-Pritchard and Time-averaged Orbiting Potential traps. The resulting double-well magnetic potential has readily controllable barrier height and well separation. This offers a new tool for studying the behavior of Bose condensates in double-well potentials, including atom interf

Tsuyoshi Kashima, Masatoshi Imada

Numerical studies on Mott transitions caused by the control of the ratio between bandwidth and electron-electron interaction ($U$) are reported. By using the recently proposed path-integral renormalization group(PIRG) algorithm, physical properties near the transitions in the ground state of two-dimensional half-filled models with the nearest and the next-ne

Jay D. Salmonson, James R. Wilson

We calculate the neutrino pair annihilation rate into electron pairs between two neutron stars in a binary system. We present a closed formula for the energy deposition rate at any point between the stars, where each neutrino of a pair derives from each star, and compare this result to that where all neutrinos derive from a single neutron star. An approximat

John P. Blakeslee, John R. Lucey, Brian J. Barris, Michael J. Hudson

We perform a series of comparisons between distance-independent photometric and spectroscopic properties used in the surface brightness fluctuations (SBF) and fundamental plane (FP) methods of early-type galaxy distance estimation. The data are taken from two recent surveys: the SBF Survey of Galaxy Distances and the Streaming Motions of Abell Clusters (SMAC

Robert A. Fesen, Jon A. Morse, Roger A. Chevalier, Kazimierz J. Borkowski

The young SNR Cassiopeia A was imaged with WFPC-2 through four filters selected to capture the complete velocity range of the remnant&#39;s main shell in several important emission lines. Primary lines detected were [O III] 4959,5007, [N II] 6583, [S II] 6716,6731 + [O II] 7319,7330 + [O I] 6300,6364, and [S III] 9069,9532. About 3/4th of the remnant&#39;s m

M. Wittkowski, C. A. Hummel, K. J. Johnston, D. Mozurkewich

We present direct measurements of the limb-darkened intensity profiles of the late-type giant stars HR5299, HR7635, and HR8621 obtained with the Navy Prototype Optical Interferometer (NPOI) at the Lowell Observatory. A triangle of baselines with lengths of 18.9 m, 22.2 m, and 37.5 m was used. We utilized squared visibility amplitudes beyond the first minimum

Sofia Feltzing, Johan Holmberg, Jarrod R. Hurley

We derive stellar ages, from evolutionary tracks, and metallicities, from Stromgren photometry, for a sample of 5828 dwarf and sub-dwarf stars from the Hipparcos Catalogue. This stellar disk sample is used to investigate the age-metallicity diagram in the solar neighbourhood. Such diagrams are often used to derive a so called age-metallicity relation. Becaus

Shiv Sethi, S. G. Bhargavi

We attempt to constrain the luminosity function of Gamma Ray Bursts (GRBs) from the observed number count--flux relation and the afterglow redshift data. We assume three classes of luminosity functions for our analysis: (a) Log-normal distribution, (b) Schechter distribution, and (c) Scale-free distribution. We assume several models of the evolution of the G

Kent S. Wood, Lev Titarchuk, Paul S. Ray, Michael T. Wolff

We present a linear diffusion model for the evolution of the double-peaked outburst in the transient source XTEJ1118+480. The model treats the two outbursts as episodic mass deposition at the outer radius of the disk followed by evolution of disk structure according to a diffusion process. We demonstrate that light curves with fast-rise, exponential decay pr

S. I. Ipatov

Migration of trans-Neptunian objects to the Earth is considered. Due to the gravitational influence of large trans-Neptunian objects and mutual collisions, some objects can get such orbits, from which they can be moved inside the Solar System under the gravitational influence of planets. About 10-20% or even more 1-km Earth-crossers could have come from the

Sarah Brough, Chris A. Collins, Doug J. Burke, Paul D. Lynam

We present the K-band Hubble diagram for 162 brightest cluster galaxies (BCGs) in X-ray selected clusters, 0.01<z<0.83. The sample incorporates that of Burke, Collins, & Mann (2000) and includes additional infrared data from the 2MASS extended source catalogue. We show that below z=0.1 the BCGs show no correlation with their environment, however, above z=0.1

C. Stanghellini, D. Dallacasa, C. P. O&#39;Dea, S. A. Baum

We present VLBA observations at 15 GHz of ten GHz Peaked Spectrum (GPS) radio sources. The cores are often difficult or impossible to locate. When likely cores are found, they account for a small fraction of the flux density in GPS galaxies - around or below 2%, while in GPS quasars they can account for more than 20% of the total flux density. We detect low

S. Veilleux

The preliminary results from a deep emission-line search for warm ionized material in the halos of nearby active and star-forming galaxies are presented. The origin of this gas is discussed in the context of galaxy formation and evolution.

F. Boone

The design of an interferometric array should allow optimal instrumental response regarding all possible source positions, times of integration and scientific goals. It should also take into account constraints such as forbidden regions on the ground due to impracticable topography. The complexity of the problem requires one to proceed by steps. A possible a

Ewan O&#39;Sullivan, Duncan A. Forbes, Trevor J. Ponman

We present a catalogue of X-ray luminosities for 401 early-type galaxies, of which 136 are based on newly analysed ROSAT PSPC pointed observations. The remaining luminosities are taken from the literature and converted to a common energy band, spectral model and distance scale. Using this sample we fit the L_X:L_B relation for early-type galaxies and find a

Domingos S. L. Soares

The affirmative statement of the existence of extraterrestrial life is tentatively raised to the status of a principle. Accordingly, Fermi&#39;s question is answered and the anthropic principle is shown to be falsifiable. The time-scale for the development of life on Earth and the age of the universe are the fundamental quantities upon which the arguments ar

F. Delplancke, K. M. Gorski, A. Richichi

Until now, the detailed interpretation of the observed microlensing events has suffered from the fact that the physical parameters of the phenomenon cannot be uniquely determined from the available astronomical measurements, i.e. the photometric lightcurves. The situation will change in the near-future with the availability of long-baseline, sensitive optica

M. Umemura, T. Nakamoto, H. Susa

Using 3D radiative transfer calculations on the reionization of an inhomogeneous universe, QSO absorption line systems are simulated and they are compared with observations of Ly$α$ continuum depression at high redshifts. By this comparison, it is found that the metagalactic UV intensity decreases rapidly with $z$ at $z>4$ as $I_{21}=0.5\exp [3(4-z)]$, and t

M. Umemura, T. Nakamoto, H. Susa

Full radiative transfer in 3D space has been solved to pursue the reionization history in an inhomogeneous universe. It has been shown that the reionization of an inhomogeneous universe is not a prompt event, but a fairly slow process. Also, QSO absorption line systems are simulated with using the results of radiative transfer calculations. Ly$α$ continuum d

F. Yusef-Zadeh, C. Law, M. Wardle, Q. D. Wang

The Arches cluster is an extraordinarily compact massive star cluster with a core radius of about 10$&#39;&#39;$ ($\sim$0.4 pc) and consisting of more than 150 O star candidates with initial stellar masses greater than 20~M$_\odot$ near G0.12-0.02. X-ray observations of the radio Arc near the Galactic center at l$\sim0.2^0$ which contains the Arches cluster

Edward A. Baltz, Hitoshi Murayama

Gravitinos with a mass in the keV range are an interesting candidate for warm dark matter. Recent measurements of the matter density of the universe and of cosmic structures at the dwarf galaxy scale rule out the simplest gravitino models with thermal freeze-out. We construct a model where the decay of the messenger particles that transmit the supersymmetry

Sergey S. Kurennoy

The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by a displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those produced by a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse

T. C. Ralph, A. G. White, W. J. Munro, G. J. Milburn

We describe the construction of a conditional quantum control-not (CNOT) gate from linear optical elements following the program of Knill, Laflamme and Milburn [Nature {\bf 409}, 46 (2001)]. We show that the basic operation of this gate can be tested using current technology. We then simplify the scheme significantly.

Risa H. Wechsler, James S. Bullock, Joel R. Primack, Andrey V. Kravtsov

(abridged) We study the relation between the density profiles of dark matter halos and their mass assembly histories, using a statistical sample of halos in a high-resolution N-body simulation of the LCDM cosmology. For each halo at z=0, we identify its merger-history tree, and determine concentration parameters c_vir for all progenitors, thus providing a st

M. E. Torio, K. Hallberg, A. H. Ceccatto, C. R. Proetto

The transmission of electrons through a non-interacting tight-binding chain with an interacting side quantum dot (QD) is analized. When the Kondo effect develops at the dot the conductance presents a wide minimum, reaching zero at the unitary limit. This result is compared to the opposite behaviour found in an embedded QD. Application of a magnetic field des

Dennis S. Keeler

Let $X$ be a scheme, proper over a commutative noetherian ring $A$. We introduce the concept of an ample filter of invertible sheaves on $X$ and generalize the most important equivalent criteria for ampleness of an invertible sheaf. We also prove the Theorem of the Base for $X$ and generalize Serre&#39;s Vanishing Theorem. We then generalize results for twis

A. Bramon, G. Garbarino

We derive new Bell&#39;s inequalities for entangled K0 anti-K0 pairs. This requires 1) mutually exclusive setups allowing either K0 vs anti-K0 or KS vs KL detection and 2) the use of kaon regenerators. The inequalities turn out to be significantly violated by Quantum Mechanics, resulting in interesting tests of Local Realism at phi-factories and p anti-p mac

G. Calderon, G. Lopez Castro

In the standard model, the top quark decay width \Gamma_t is computed from the exclusive t -> bW decay. We argue in favor of using the three body decays t-> bf_i\bar{f}_j to compute \Gamma_t as a sum over these exclusive modes. As dictated by the S-matrix theory, these three body decays of the top quark involve only asymptotic states and incorporate the widt

P. Jacob, P. Mathieu

A new basis of states for highest-weight modules in $\ZZ_k$ parafermionic conformal theories is displayed. It is formulated in terms of an effective exclusion principle constraining strings of $k$ fundamental parafermionic modes. The states of a module are then built by a simple filling process, with no singular-vector subtractions. That results in fermionic

K. Ulker

The relation between BRST cohomology and the N=1 supersymmetric Yang-Mills action in 4 dimensions is discussed. In particular, it is shown that both off and on shell N=1 SYM actions are related to a lower dimensional field polynomial by solving the descent equations, which is obtained from the cohomological analysis of linearized Slavnov-Taylor operator $\B$

N. M. Chtchelkatchev, W. Belzig, Yu. V. Nazarov, C. Bruder

Superconductor-Ferromagnetic-Superconductor (SFS) Josephson junctions are known to exhibit a transition between $π$ and 0 states. In this note we find the $π-0$ phase diagram of an SFS junction depending on the transparency of an intermediate insulating layer (I). We show that in general, the Josephson critical current is nonzero at the $π-0$ transition temp

Jorge Alfaro, Hugo A. Morales-Técotl, Luis F. Urrutia

Within loop quantum gravity we construct a coarse-grained approximation for the Einstein-Maxwell theory that yields effective Maxwell equations in flat spacetime comprising Planck scale corrections. The corresponding Hamiltonian is defined as the expectation value of the electromagnetic term in the Einstein-Maxwell Hamiltonian constraint, regularized a la Th

Wenfei Yu, Michiel van der Klis, Peter Jonker

We analysed RXTE data of Sco X-1 which show kHz quasi-periodic oscillations (QPOs) and the $\sim$6--8 Hz normal-branch oscillation (NBO) simultaneously. Using power spectra of 0.03--0.5 s data segments, we find that both the upper kHz QPO frequency $ν_2$ and the ratio of lower to upper kHz QPO amplitude are anticorrelated to variations in the X-ray count-rat

Maarten Golterman, Elisabetta Pallante

In the calculation of non-leptonic weak decay rates, a "mismatch" arises when the QCD evolution of the relevant weak hamiltonian down to hadronic scales is performed in unquenched QCD, but the hadronic matrix elements are then computed in (partially) quenched lattice QCD. This mismatch arises because the transformation properties of penguin operators under c

Doron Cohen, Natasha Lepore, Eric J. Heller

The plane-wave decomposition method (PWDM), a widely used means of numerically finding eigenstates of the Helmholtz equation in billiard systems is described as a variant of the mathematically well-established boundary integral method (BIM). A new unified framework encompassing the two methods is discussed. Furthermore, a third numerical method, which we cal

Stefano Mancini, Vittorio Giovannetti, David Vitali, Paolo Tombesi

It is shown that radiation pressure can be profitably used to entangle {\it macroscopic} oscillators like movable mirrors, using present technology. We prove a new sufficient criterion for entanglement and show that the achievable entanglement is robust against thermal noise. Its signature can be revealed using common optomechanical readout apparatus.

A. P. Balachandran, S. Digal

We extend and generalize the seminal work of Brandenberger, Huang and Zhang on the formation of strings during chiral phase transitions(berger) and discuss the formation of abelian and non-abelian topological strings during such transitions in the early Universe and in the high energy heavy-ion collisions. Chiral symmetry as well as deconfinement are restore

Masatoshi Imanishi, C. C. Dudley, Philip R. Maloney

We report on the results of 3--4 $μ$m spectroscopy of the ultra-luminous infrared galaxy (ULIRG) UGC 5101. It has a cool far-infrared color and a LINER-type optical spectrum, and so, based on a view gaining some currency, would be regarded as dominated by star formation. However, we find that it has strong 3.4 $μ$m carbonaceous dust absorption, low-equivalen

Simeon Pol&#39;shin

We construct the systems of generalised coherent states for the discrete and continuous spectra of the hydrogen atom. These systems are expressed in elementary functions and are invariant under the $SO(3, 2)$ (discrete spectrum) and $SO(4, 1)$ (continuous spectrum) subgroups of the dynamical symmetry group $SO(4, 2)$ of the hydrogen atom. Both systems of coh

Daisuke Ida, Tetsuya Shiromizu, Hirotaka Ochiai

We discuss the semiclassical instability of the Randall-Sundrum brane-world model against a creation of a kind of Kaluza-Klein bubble. An example describing such a bubble space-time is constructed from the five-dimensional AdS-Schwarzschild metric. The induced geometry of the brane looks like the Einstein-Rosen bridge, which connects the positive and the neg

N. Brambilla, Y. Sumino, A. Vairo

We study the spectra of the bottomonium and B_c states within perturbative QCD up to order alpha_s^4. The O(Lambda_QCD) renormalon cancellation between the static potential and the pole mass is performed in the epsilon-expansion scheme. We extend our previous analysis by including the (dominant) effects of non-zero charm-quark mass in loops up to the next-to

Olindo Corradini, Alberto Iglesias, Zurab Kakushadze, Peter Langfelder

We study gravity in codimension-2 brane world scenarios with infinite volume extra dimensions. In particular, we consider the case where the brane has non-zero tension. The extra space then is a two-dimensional ``wedge&#39;&#39; with a deficit angle. In such backgrounds we can effectively have the Einstein-Hilbert term on the brane at the classical level if

Andrew M. Childs, Edward Farhi, John Preskill

We study the fault tolerance of quantum computation by adiabatic evolution, a quantum algorithm for solving various combinatorial search problems. We describe an inherent robustness of adiabatic computation against two kinds of errors, unitary control errors and decoherence, and we study this robustness using numerical simulations of the algorithm.

A. Mair, J. Hager, D. F. Phillips, R. L. Walsworth

We report the demonstration of phase coherence and control for the recently developed &#34;light storage&#34; technique. Specifically, we use a pulsed magnetic field to vary the phase of atomic spin excitations which result from the deceleration and storing of a light pulse in warm Rb vapor. We then convert the spin excitations back into light and detect the

Antoine Suarez

An alternative description imbedding nonlocality in a relativistic chronology is proposed. It is argued that vindication of Quantum Mechanics in forthcoming experiments with moving beam-splitters would mean that there is no real time ordering behind the nonlocal correlations.

Frank Verstraete, Jeroen Dehaene, Bart De Moor

All mixed states of two qubits can be brought into normal form by the action of SLOCC operations of the kind $ρ&#39;=(A\otimes B)ρ(A\otimes B)^\dagger$. These normal forms can be obtained by considering a Lorentz singular value decomposition on a real parameterization of the density matrix. We show that the Lorentz singular values are variationally defined a

H. Ahmedov, I. H. Duru

Exact path integration for the one dimensional potential $V=b^2\cos 2q$ which describes the finite amplitude pendulum is presented.

Masahito Hayashi

In this paper, we give another proof of quantum Stein&#39;s lemma by calculating the information spectrum, and study an asymptotic optimal measurement in the sense of Stein&#39;s lemma. We propose a projection measurement characterized by the irreducible representation theory of the special linear group SL(H). Specially, in spin 1/2 system, it is realized by

Shohini Ghose, Paul M. Alsing, Ivan H. Deutsch

We have identified ultra-cold atoms in magneto-optical double-well potentials as a very clean setting in which to study the quantum and classical dynamics of a nonlinear system with multiple degrees of freedom. In this system, entanglement at the quantum level and chaos at the classical level arise from nonseparable couplings between the atomic spin and its

M. A. Kiselev, P. Lesieur, A. M. Kisselev, D. Lombardo

New model of separated form factors is proposed for the evaluation of small-angle neutron scattering curves from large unilamellar vesicles. The validity of the model was checked by comparison to the model of hollow sphere. The model of separated form factors and hollow sphere model give reasonable agreement in the evaluation of vesicle parameters.

Mojca Cepic

A simple experiment is presented that enables qualitative and quantitative measurement of the extraordinary refractive index direction dependency in an uniaxial nematic liquid crystal. Three liquid crystaline cells were designed in which elongated molecules of nematic liquid crystal align in directions which enable to observe the variation of extraordinary r

C. P. Kouropoulos

We consider a pair of harmonic oscillators in two or three dimensions of space coupled by the standard electrodynamic forces : the Coulomb, the Lorentz and the electrokinetic forces. The addition of the Lorentz force is mainly felt in the short range and suppresses the radial correlated oscillating mode of such coupled oscillators. This imposes constraints o

H. Y. Guo, Y. Q. Li, K. Wu

We present the symplectic algorithm in the Lagrangian formalism for the Hamiltonian systems by virtue of the noncommutative differential calculus with respect to the discrete time and the Euler--Lagrange cohomological concepts. We also show that the trapezoidal integrator is symplectic in certain sense.

C. Barbieri, W. H. Dickhoff

Theoretical calculations of one- and two-hole spectral functions for the O16 nucleus are still failing to describe some of the important features observed experimentally. Of critical importance for the solution of these issues is to obtain an appropriate description of the interplay between hole-hole and particle-hole excitations. A formalism is reviewed her

V. B. Belyaev, N. V. Shevchenko, S. A. Rakityansky, W. Sandhas

A microscopic four-body description of near-threshold coherent photoproduction of the $η$ meson on the (3N)-nuclei is given. The photoproduction cross-section is calculated using the Finite Rank Approximation (FRA) of the nuclear Hamiltonian. The results indicate that the final state interaction of the $η$ meson with the residual nucleus plays an important r

C. Forssen, V. D. Efros, M. V. Zhukov

An analytical model is developed to study the spectra of electromagnetic dissociation of two-neutron halo nuclei without precise knowledge about initial and final states. Phenomenological three-cluster bound state wave functions, reproducing the most relevant features of these nuclei, are used along with no interaction final states. The 6-He nucleus is consi

Jan-e Alam, T. Hatsuda, Tapan K. Nayak, Pradip Roy

We compare the photon emission rates from hot hadronic matter with in-medium mass shift and Quark Gluon Plasma (QGP). It is observed that the WA98 data can be well reproduced by hadronic initial state with initial temperature $\sim 200$ MeV if the universal scaling of temperature dependent hadronic masses are assumed and the evolution of temperature with tim

A. I. Titov, B. Kampfer

The isoscalar-isovector ($ρ-ω$) interferences in the exclusive reactions $π^- p \to n e^+ e^-$ and $π^+ n \to p e^+ e^-$ near the $ω$ threshold leads to a distinct difference of the dielectron invariant mass distributions depending on beam energy. The strength of this effect is determined by the coupling of resonances to the nucleon vector-meson channels and

I. Niculescu

As part of a broader study of kaon photoproduction on deuterium, the $γn \to K^{+} Σ^{-} $ channel was investigated. The data were acquired at Jefferson Lab using the CLAS detector and the Photon-Tagging Facility installed in Hall B. The photon energy range covered was from 0.50 to 2.95 GeV. For the present analysis, the $γn \to K^{+} Σ^{-}$ channel was iden

Nicholas R. Cerruti, Steven Tomsovic

The sensitivity of a wave field&#39;s evolution to small perturbations is of fundamental interest. For chaotic systems, there are two distinct regimes of either exponential or Gaussian overlap decay in time. We develop a semiclassical approach for understanding both regimes, and give a simple expression for the crossover time between the regimes. The wave fi

Paolo Lorenzoni

In this paper we study the deformations of bihamiltonian PDEs of hydrodynamic type with one dependent variable. The reason we study such deformations is that the deformed systems maintain an infinite number of commuting integrals of motion up to a certain order in the deformation parameter. This fact suggests that these systems could have, at least for small

E. Ahmed, A. S. Hegazi, A. S. Elgazzar

A modified version of susceptible-infected-recovered-susceptible (SIRS) model for the outbreaks of foot-and-mouth disease (FMD) is introduced. The model is defined on small-world networks, and a ring vaccination programme is included. This model can be a theoretical explanation for the nonlocal interactions in epidemic spreading. Ring vaccination is capable

V. Kreiman, V. Lakshmibai

We give a closed-form formula for the Hilbert function of the tangent cone at the identity of a Schubert variety X in the Grassmannian in both group theoretic and combinatorial terms. We also give a formula for the multiplicity of X at the identity, and a Grobner basis for the ideal defining the intersection of X with the opposite cell as a closed subvariety

Dave Auckly, Lev Kapitanski

We discuss matching control laws for underactuated systems. We previously showed that this class of matching control laws is completely charactarized by a linear system of first order partial differential equations for one set of variables followed by a linear system of first order PDEs for a second set of variables. Here we derive a new first order system o

Friedrich Knop

Let a connected reductive group G act on the smooth connected variety X. The cotangent bundle of X is a Hamiltonian G-variety. We show that its &#34;total moment map&#34; has connected fibers. This is an expanded version of section 6 of my paper dg-ga/9712010 on Weyl groups of Hamiltonian manifolds.

Masaki Kashiwara, Pierre Schapira

We define the notions of micro-support and regularity for ind-sheaves, and prove their invariance by contact transformations. We apply the results to the ind-sheaves of temperate holomorphic solutions of D-modules. We prove that the micro-support of such an ind-sheaf is the characteristic variety of the corresponding D-module and that the ind-sheaf is regula

Marcos Marino, Cumrun Vafa

We study the framing dependence of the Wilson loop observable of U(N) Chern-Simons gauge theory at large N. Using proposed geometrical large N dual, this leads to a direct computation of certain topological string amplitudes in a closed form. This yields new formulae for intersection numbers of cohomology classes on moduli of Riemann surfaces with punctures

A. A. Kirillov, D. Turaev

We use an extended quantum field theory (EQFT) hep-th/9911168 to explore possible observational effects of the spacetime. It is shown that as it was expected the spacetime foam can provide quantum bose fields with a cutoff at very small scales, if the energy of zero - point fluctuations of fields is taken into account. It is also shown that EQFT changes the