September 2000 arXiv papers — page 24

A. A. Pivovarov

The cross section near the $t\bar t$ production threshold in $e^+e^-$ annihilation and $γγ$ collisions is discussed. The NNLO results within NRQCD are briefly overviewed.

H. G. Dosch

We present a short overview over the different contributions to high energy photon photon scattering and explore the possibilities of tuning the sizes of the scattered objects by changing the virtuality of the photons. We compare the experimental data with model calculations. The difficulties with inclusive charm production are discussed.

Fu Jinghua, Meng Ta-chung, R. Rittel, K. Tabelow

Experimental evidence and theoretical arguments for the existence of self-organized criticality in systems of gluons and quarks are presented. It is observed that the existing data for high-transverse-momentum jet-production exhibit striking regularities; and it is shown that, together with first-principle considerations, such regularities can be used, not o

Mikolaj Misiak

Status of the theoretical B -> X_s gamma and B -> X_s l^+ l^- analyses is reviewed. Recently completed perturbative calculations are mentioned. The level at which non-perturbative effects are controlled is discussed.

Y. N. Srivastava, A. Widom

Employing the experimental electro-weak interactions between quarks and leptons, the spin of the proton may easily be understood in terms of the spins of the constituent quarks.

F. Assaoui, T. Lhallabi

The development of the N = 4 supersymmetric approach to quantum cosmology based on the non-compact global O(d,d) symmetries of the effective action is given. The N = 4 supersymmetric action whose bosonic sector is invariant under O(d,d) is determined. A representation for supercharges is obtained and the form of the zero and one-fermion quantum states leadin

R. D. Peccei

I discuss here some of the constraints imposed by quantum and gravitational corrections on two hypothetical excitations, axions and quintessence, which have important cosmological implications. Although these corrections can be kept under control, the resulting constraints are not too natural. In particular, to keep the quintessence field light one must esse

M. Steinhauser

In the recent years there has been an enormous development in the evaluation of higher order quantum corrections. An essential ingredient in the practical calculations is provided by vacuum diagrams, i.e. integrals without external momenta. In this paper a program package is described which can deal with one-, two- and three-loop vacuum integrals with one no

G. P. Skoro, M. V. Tokarev

The gamma +jet production in p(->)-p(->) collisions at high energies is studied. Double-spin asymmetry A{LL} of the process is calculated by using Monte Carlo code SPHINX. The predictions for A{LL} of the gamma +jet production in the p(->)-p(->) collisions using the spin-dependent gluon distributions with positive and negative sign of $ΔG(x,Q^2)$ are made at

Ja. V. Burdanov, G. V. Efimov

Using a simple relativistic QFT model of scalar fields we demonstrate that the analytic confinement (propagator is an entire function in the complex p^2-plane) and the weak coupling constant lead to the Regge behaviour of the two-particle bound states. In QCD we assume that the gluon vacuum is realized by the selfdual homogeneous classical field which is the

Gert Aarts

The nonperturbative real-time evolution of quantum fields out of equilibrium is often solved using a mean-field or Hartree approximation or by applying effective action methods. In order to investigate the validity of these truncations, we implement similar methods in classical scalar field theory and compare the approximate dynamics with the full nonlinear

Gino Isidori

Rare B decays of the type $b \to s~\ell^+\ell^-(ν\barν)$ are analyzed in a generic scenario where New Physics effects enter predominantly via $Z$ penguin contributions. We show that this possibility is both phenomenologically allowed and well motivated on theoretical grounds. The important role played in this context by the lepton forward-backward asymmetry

L. T. Handoko

We discuss the isospin symmetry breaking quantity Δ^{\pm 0} = Γ(B^\pm -> ρ^\pm γ)/[2 Γ(B^0 -> ρ^0 γ)] - 1, and the direct CP violation in B^\pm -> ρ^\pm γwithin and beyond the standard model. After showing that the leading-order calculation would be a good approximation in such models, we argue that measurements of these quantities would be able to disentagl

Gi-Chol Cho

We study constraints on the Minimal Supersymmetric Standard Model from electroweak experiments. We find that the light sfermions always make the fit worse than the Standard Model, while the light chargino generally make the fit slightly better through the oblique corrections. The best overall fit to the precision measurements are found when the mass of light

Yue-Liang Wu

We show how the nearly bi-maximal mixing scenario comes out naturally from gauged $SO(3)_{F}$ flavor symmetry via spontaneous symmetry breaking. An interesting relation between the neutrino mass-squared differences and the mixing angle, i.e., $Δm_{μe}^2 / Δm_{τμ}^2 \simeq 2|U_{e 3}|^2 $ is obtained. The smallness of the ratio (or $|U_{e 3}|$) can also natura

E. D. Zimmerman

Recent resuls from experiments at Fermilab and the Paul Scherrer Institute have constrained the parameter space available for a hypothetical particle $Q^0$ produced in the decay $π^+ \to μ^+ Q^0$. This decay has been invoked to explain a peculiar feature of an event arrival time distribution observed in the KARMEN neutrino experiment.

Wei Min Jin

On a static spacetime, the solutions of the Dirac equation are generated by a time-independent Hamiltonian. We study this Hamiltonian and characterize the split into positive and negative energy. We use it to find explicit expressions for advanced and retarded fundamental solutions and for the propagator. Finally, we use a fermion Fock space based on the pos

Wei Min Jin

With a generally covariant equation of Dirac fields outside a black hole, we develop a scattering theory for massive Dirac fields. The existence of modified wave operators at infinity is shown by implementing a time-dependent logarithmic phase shift from the free dynamics to offset a long-range mass term. The phase shift we obtain is a matrix operator due to

Chopin Soo

The anti-self-dual projection of the spin connections of certain four-dimensional Einstein manifolds can be Abelian in nature. These configurations signify bundle reductions. By a theorem of Kobayashi and Nomizu such a process is predicated on the existence of a covariantly constant field. It turns out that even without fundamental Higgs fields and other phy

A. Barros, A. A. Sen, C. Romero

The gravitational field of a stationary circular cosmic string loop ,externally supported against collapse, is investigated in the context of Brans-Dicke theory in the weak field approximation of the field equations. The solution is quasi-conformally related to the corresponding solution in Einstein's General Relativity(GR) and goes over to the correspon

W. C. Barber, D. P. Belanger

Monte Carlo techniques are used to investigate the equilibrium threshold concentration, xe, in the dilute anisotropic antiferromagnet Fe(x)Zn(1-x)F2 in an applied magnetic field, considered to be an ideal random-field Ising model system. Above xe equilibrium behavior is observed whereas below xe metastability and domain formation dominate. Monte Carlo result

Arkadiusz Wojs

The electron correlations near the half-filling of the lowest and excited Landau levels (LL's) are studied using numerical diagonalization. It is shown that in the low lying states electrons avoid pair states with relative angular momenta ${\cal R}$ corresponding to positive anharmonicity of the interaction pseudopotential $V({\cal R})$. In the lowest LL

A. Foerster, X. -W. Guan, J. Links, I. Roditi

The Bariev model with open boundary conditions is introduced and analysed in detail in the framework of the Quantum Inverse Scattering Method. Two classes of independent boundary reflecting $K$-matrices leading to four different types of boundary fields are obtained by solving the reflection equations. The models are exactly solved by means of the algebraic

G. F. Zharkov

The paramagnetic Meissner effect (PME) is observed in small superconducting samples, and a number of controversial explanations of this effect are proposed, but there is as yet no clear understanding of its nature. In the present paper PME is considered on the base of the Ginzburg-Landau theory (GL). The one-dimensional solutions are obtained in a model case

E. Janod, L. Leonyuk, V. Maltsev

Magnetic properties of the natural mineral Cu$_2$(OH)$_2$CO$_3$ (malachite) were investigated through DC and AC susceptibility measurements. The analysis of the low-temperature part reveals a quantum spin-gap behavior with $Δ\approx 130 K$. Consistently with the crystal structure, the magnetic susceptibility can be accurately described by a model of alternat

K. J. H. van Bemmel, H. Schomerus, C. W. J. Beenakker

We investigate the low-frequency dynamics for transmission or reflection of a wave by a cavity with chaotic scattering. We compute the probability distribution of the phase derivative phi'=d phi/d omega of the scattered wave amplitude, known as the single-mode delay time. In the case of a cavity connected to two single-mode waveguides we find a marked di

D. Karevski

The surface magnetization of the quantum XY chain in a transverse field is found for arbitrary nearest neighbour interactions in closed form. This allows to derive the bulk phase diagram in a simple way. The magnetic surface behaviour and the bulk correlation length are found exactly.

Leonid Didukh, Vasyl Hankevych

In the present paper pressure-temperature phase diagram of a generalized Hubbard model with correlated hopping in a paramagnetic state at half-filling is determined by means of the generalized mean-field approximation in the Green function technique. The constructed phase diagram describes metal-to-insulator transition with increasing temperature, and insula

N. Furukawa, Y. Shimomura, T. Akimoto, Y. Moritomo

Low temperature resistivity of CMR manganites is investigated. At the ground state, conduction electrons are perfectly spin polarized, which is called half-metallic. From one-magnon scattering processes, it is discussed that the resistivity of a half metal as a function of temperature scales as rho(T) - rho(0) propto T^3. We take (Nd,Tb,Sr)MnO_3 as an exampl

T. Akimoto, Y. Moritomo, A. Nakamura, N. Furukawa

Temperature variation of resistivity and specific heat have been measured for prototypical half-metallic ferromagnets, R_0.6Sr_0.4MnO_3, with controlling the one-electron bandwidth W. We have found variation of the temperature scalings in the resistivity from T^2 (R = La, and Nd) to T^3 (R = Sm), and have interpreted the $T^3-law in terms of the anomalous si

Ya. B. Bazaliy, B. A. Jones, Shou-Cheng Zhang

Several recent experimental studies have confirmed the possibility of switching the magnetization direction in the small magnetic domains by pumping large spin-polarized currents through them. On the basis of equations proposed by J.Slonczewski for the case when magnetization of the domains is almost uniform, we analyze the stability and switching for two ty

C. W. J. Beenakker, H. Schomerus

A theory is presented for the photodetection statistics of radiation produced by current fluctuations in a phase-coherent conductor. Deviations are found from the Poisson statistics that would result from a classical current. For detection in a narrow frequency interval, the photocount distribution has the negative-binomial form of black-body radiation if th

S. Lupi, P. Calvani, M. Capizzi, P. Roy

An optical "pseudogap" is usually assumed to open at low T in the "anomalous Drude" absorption, which models the optical conductivity sigma(omega) (proportional to omega-1) of HCTS by a linewidth Gamma (on the order of 1000 cm-1) varying with omega. In the sigma(omega) of BSCO, measured down to 10 cm-1, we have resolved instead: i) a normal D

Robert G. Crittenden, Priyamvada Natarajan, Ue-Li Pen, Tom Theuns

Large scale correlations in the orientations of galaxies can result from alignments in their angular momentum vectors. These alignments arise from the tidal torques exerted on neighboring proto-galaxies by the smoothly varying shear field. We compute the predicted amplitude of such ellipticity correlations using the Zel'dovich approximation for a realist

Michael Blanton, Huan Lin

We present a simple functional form for the joint distribution of R-band luminosity and [OII] 3727 emission-line equivalent widths of galaxies, and show that this form is a good fit to the galaxies in the Las Campanas Redshift Survey. We find a relationship between [OII] equivalent width W and R-band luminosity L_R of the approximate form: <W> \approx (10 Å)

Brad K. Gibson, Mark L. Giroux, John T. Stocke, J. Michael Shull

Tantalizing evidence has been presented supporting the suggestion that a large population of extragalactic gas clouds permeates the Local Group, a population which has been associated with the Galactic High-Velocity Clouds (HVCs). We comment on both the strengths and weaknesses of this suggestion, informally referred to as the Blitz/Spergel picture. Theoreti

Sergei. V. Zharikov, Gaghik. H. Tovmassian, Juan Echevarria, Aixa Aube Cardenas;

The detection of the orbital period of 4.36his reported for the new Intermediate Polar 1 WGA 1958.2+3232. The orbital period was derived from time-resolved photometric and spectral observations. We also confirmed the 733 sec spin period of the White Dwarf consistent with the X-ray pulsations and were able to distinguish the beat period in the light curve. St

Paul L. Schechter

The 0th, 1st and 2nd derivatives of a ``Fermat potential&#39;&#39; give the three D&#39;s of gravitational lensing: delay, deflection and distortion. Observations of these delays, deflections and distortions for doubly and quadruply imaged quasars give estimates of Hubble&#39;s constant, H_0. The single largest contribution to the uncertainty in H_0 arises f

M. M. Dworetsky, J. Budaj

We make new Non-LTE calculations to deduce abundances of neon from visible-region echelle spectra of selected Ne I lines in 7 normal stars and 20 HgMn stars. We find that the best strong blend-free Ne line which can be used at the lower end of the Teff range is 6402 A, although several other potentially useful Ne I lines are found in the red region of the sp

O. E. Rognvaldsson, T. R. Greve, J. Hjorth, E. H. Gudmundsson

We have obtained U and R band observations of the depletion of background galaxies due to the gravitational lensing of the galaxy cluster CL0024+1654 (z=0.39). The radial depletion curves show a significant depletion in both bands within a radius of 40&#39;&#39;-70&#39;&#39; from the cluster center. This is the first time depletion is detected in the U band.

N. Masetti, F. Frontera, L. Stella, M. Orlandini

We report on 4 BeppoSAX Target Of Opportunity observations of MXB 1730-335, the Rapid Burster (RB), made during the 1998 February-March outburst. In the first observation, approximately 20 days after the outburst peak, the X-ray light curve showed Type II bursts at a rate of 43 per hour. Nine days later, during the second BeppoSAX pointing, only 5 Type II bu

N. Neininger

We have accumulated 12CO(1-0) and (2-1) data of several GMCs in M31 using the Plateau de Bure Interferometer. The sample covers a range of 5 to 18 kpc galactocentric distance and various physical conditions. The spatial resolution attains values down to 3 pc. All GMCs investigated have been resolved into several components, also seemingly quiescent clouds an

Daniel Pfenniger

A series of arguments is presented for heavy galaxy disks not only in the optical regions, but also in the dark matter dominated regions of spirals. We are testing this possibility with extreme maximum disk N-body models without any conventional spheroidal dark halo.

K. D. Borne, H. Bushouse, L. Colina, R. A. Lucas

We summarize results from an on-going Hubble Space Telescope (HST) survey of a large sample of ULIRGs (Ultra-Luminous IR Galaxies). New ground-based multi-fiber spectroscopic observations are now being obtained to complement the HST data and to assist in the interpretation of these complex objects.

Yurii E. Lozovik, Andrey M. Popov

The energetic characteristics of two-shell carbon nanoparticles (&#34;onions&#34;) with different shapes of second shell are calculated. The barriers of relative rotation of shells are found to be surprisingly small; therefore, free relative rotation of shells can take place at room temperature. The intershell orientational melting of the nanoparticle $C_{60

Y. P. Jing, G. Boerner

We report the results of an analysis of the redshift power spectrum $P^S(k,μ)$ in three typical Cold Dark Matter (CDM) cosmological models, where $μ$ is the cosine of the angle between the wave vector and the line-of-sight. Two distinct biased tracers derived from the primordial density peaks of Bardeen et al. and the cluster-underweight model of Jing, Mo, &

Jim Bryan, Rahul Pandharipande

The Gopakumar-Vafa conjecture is defined and studied for the local geometry of a curve in a Calabi-Yau 3-fold. The integrality predicted in Gromov-Witten theory by the Gopakumar-Vafa BPS count is verified in a natural series of cases in this local geometry. The method involves Gromov-Witten computations, Mobius inversion, and a combinatorial analysis of the

Denis V. Juriev

Hypothesis of an existence of the universal quantum string field for all interactive phenomena is formulated. Its practical value is clarified.

V. L. Kalashnikov, D. O. Krimer, I. G. Poloyko

Based on self - consistent field theory we study a soliton generation in cw solid-state lasers with semiconductor saturable absorber. Various soliton destabilizations, i.e. the switch from femtosecond to picosecond generation (&#39;&#39;picosecond collapse&#39;&#39;), an automodulation regime, breakdown of soliton generation and hysteresis behavior, are pred

Bin Wang, Zu-guo Yu

On the study of protein folding, our understanding about the protein structures is limited. In this paper we find one way to characterize the compact structures of lattice protein model. A quantity called Partnum is given to each compact structure. The Partnum is compared with the concept Designability of protein structures emerged recently. It is shown that

Max S. Zolotorev, Kirk T. McDonald

The main features of radiation by relativistic electrons are well approximated in the Weizsacker-Williams method of virtual quanta. This method is best known for its application to radiation during elementary particle collisions, but is equally useful in describing &#34;classical&#34; radiation emitted during the interaction of a single relativistic electron

Andrey A. Sukhorukov, Yuri S. Kivshar, Ole Bang, Jens J. Rasmussen

We study the effects produced by competition of two physical mechanisms of energy localization in inhomogeneous nonlinear systems. As an example, we analyze spatially localized modes supported by a nonlinear impurity in the generalized nonlinear Schrödinger equation and describe three types of nonlinear impurity modes --- one- and two-hump symmetric localize

Sergei Ovchinnikov

It is shown that a piecewise linear function can be represented as a Max-Min polynomial of its linear components.

Yi Ling

In this paper we give a general introduction to supersymmetric spin networks. Its construction has a direct interpretation in context of the representation theory of the superalgebra. In particular we analyze a special kind of spin networks with superalgebra $Osp(1|2n)$. It turns out that the set of corresponding spin network states forms an orthogonal basis

Sumit R. Das, Antal Jevicki, Samir D. Mathur

We examine the spectrum of small vibrations of giant gravitons, when the gravitons expand in the anti-de-Sitter space and when they expand on the sphere. For any given angular harmonic, the modes are found to have frequencies related to the curvature length scale of the background; these frequencies are independent of radius (and hence angular momentum) of t

Yi Ling, Lee Smolin

We show that ${\cal N}=1$ supergravity with a cosmological constant can be expressed as constrained topological field theory based on the supergroup $Osp(1|4)$. The theory is then extended to include timelike boundaries with finite spatial area. Consistent boundary conditions are found which induce a boundary theory based on a supersymmetric Chern-Simons the

Alan Chodos, Hisakazu Minakata, Fred Cooper, Anupam Singh

We describe how a generalization of the original Gross-Neveu model from U(N) to O(N) flavor symmetry leads to the appearance of a pairing condensate at high density, in agreement with the conjectured phenomenon of color superconductivity in $(3+1)$-dimensional QCD. Moreover, the model displays a rich phase structure which closely resembles the one expected i

Liu Lianshou, Chen Gang, Fu Jinghua

A study of the dynamical fluctuation property of jets is carried out using Monte Carlo method. The results suggest that, unlike the average properties of the hadronic system inside jets, the anisotropy of dynamical fluctuations in these systems changes abruptly with the variation of the cut parameter $\yct$. A transition point exists, where the dynamical flu

Ivone F. M. Albuquerque, Lam Hui, Edward W. Kolb

Superheavy ($M>10^{10}$ GeV) particles produced during inflation may be the dark matter, independent of their interaction strength. Strongly interacting superheavy particles will be captured by the sun, and their annihilation in the center of the sun will produce a flux of energetic neutrinos that should be detectable by neutrino telescopes. Depending on the

NuTeV Collaboration, T. Adams, A. Alton, S. Avvakumov

A search for long-lived neutral particles (N^0) which decay into at least one muon has been performed using an instrumented decay channel at the E815 (NuTeV) experiment at Fermilab. The decay channel was composed of helium bags interspersed with drift chambers, and was used in conjunction with the NuTeV neutrino detector to search for N^0 decays. The data we

Changguo Lu, Kirk T. McDonald

We use Green&#39;s reciprocation theorem and the method of weighting fields to deduce the charge distribution on the cathode of a straw tube proportional chamber. The time dependence of the associated current is also discussed.

TRIUMF Munoic Hydrogen Collaboration, M. C. Fujiwara, A. Adamczak, J. M. Bailey

Studies of muonic atoms and muon catalyzed fusion have been conventionally done in a bulk target of gas, liquid or solid hydrogen isotopes. The use of thin film targets developed at TRIUMF have notable advantages in tackling some of the most important questions in the field, which could be further exploited at future high intensity muon sources. We review th

Erik D. Demaine, Martin L. Demaine, Joseph O&#39;Rourke

We prove that two pushing-blocks puzzles are intractable in 2D. One of our constructions improves an earlier result that established intractability in 3D [OS99] for a puzzle inspired by the game PushPush. The second construction answers a question we raised in [DDO00] for a variant we call Push-1. Both puzzles consist of unit square blocks on an integer latt

Jorge Talamantes, Michael Pollak

The problem of two electrons in a two-dimensional random potential is addressed numerically. Specifically, the role of the Coulomb interaction between electrons on localization is investigated by writing the Hamiltonian on a localized basis and diagonalizing it exactly. The result of that procedure is discussed in terms of level statistics, the expectation v

Martin Weigel, Wolfhard Janke

Motivated by the results of two-dimensional conformal field theory (CFT) we investigate the finite-size scaling of the mass spectrum of an Ising model on three-dimensional lattices with a spherical cross section. Using a cluster-update Monte Carlo technique we find a linear relation between the masses and the corresponding scaling dimensions, in complete ana

Benjamin P. Vollmayr-Lee, Erik Luijten

We consider d-dimensional systems with nonintegrable, algebraically decaying pairwise interactions. It is shown that, upon introduction of periodic boundary conditions and a long-distance cutoff in the interaction range, the bulk thermodynamics can be obtained rigorously by means of a Kac-potential treatment, leading to an exact, mean-field-like theory. This

I. Luk&#39;yanchuk

As was firstly shown by E. Bogomolny, the critical Ginzburg-Landay (GL) parameter kappa =1/sqrt{2} at which a superconductor changes its behavior from type-I to type-II, is the special highly degenerate point where Abrikosov vortices do not interact and therefore all vortex states have the same energy. Developing a secular perturbation theory we studied how

D. P. Belanger

The current status of experiments on the d=2 and d=3 random-exchange and random-field Ising models, as realized in dilute anisotropic antiferromagnets, is discussed. Two areas of current investigation are emphasized. For d=3, the large random field limit is being investigated and equilibrium critical behavior is being characterized at high magnetic concentra

E. G. Mishchenko

It is shown that measurements of zero-frequency shot-noise can provide information on electron-electron interaction, because the strong interaction results in the nonlinear voltage dependence of the shot noise in metallic wires. This is due to the fact that the Wiedemann-Franz law is no longer valid in the case of considerable electron-electron interaction.

E. Pignatelli, G. Fasano

We present GASPHOT, a tool for automated surface photometry and morphological classification of galaxies in deep and wide fields. The requirements for any such tool are reviewed, and its use for the classification of high-z galaxies is presented. In the case if HDF-like images, for galaxies having a magnitude ranging from 24 to 27.5, the uncertainties on the

Patricia T. Boyd, Alan P. Smale, Jeroen Homan, Peter G. Jonker

We present results from three observations with the Rossi X-ray Timing Explorer (RXTE) of LMC X-3, obtained while the source was in an extended &#39;low/hard&#39; state. The data reveal a hard X-ray spectrum which is well fit by a pure power law with photon index Gamma=1.69+/-0.02, with a source luminosity at 50 kpc of 5-16x10^{36}erg/s (2--10 keV). Strong b

P. A. Caraveo, R. P. Mignani, A. De Luca, S. Wagner

High resolution images of the Crab-like SNR SNR0540-69 have been recently obtained by the HRC, on board the Chandra X-ray Observatory, and by the FORS1 instrument, attached to ESO/VLT1. A detailed comparison of these images with an archival Planetary Camera one will be presented.

A. De Luca, R. P. Mignani, P. A. Caraveo

The quest for the distance of the Vela and Geminga pulsars yielded, so far, a set of four WFPC2 images for each object. The availability of couples of images taken at the same period of the year, thus affected by the same parallactic displacement, prompted us to use Vela and Geminga as test cases to assess the reliability of HST astrometry.

R. P. Mignani, P. A. Caraveo, A. De Luca

Given their intrinsic faintness, isolated neutron stars represent an elusive target for optical astronomy. Up to date, an optical counterpart has been identified only for a very tiny fraction of the overall population of more than 1000 radio pulsars. The HST contributions to the optical studies of isolated neutron stars have been recently reviewed by Mignani

Wlodzimierz Bryc

We show that classical processes corresponding to operators what satisfy a q-commutative relation have linear regressions and quadratic conditional variances. From this we deduce that Bell&#39;s inequality for their covariances can be extended from q=-1 to the entire range -1<q<1.

Walter Appel, Michael K. -H. Kiessling

A new, relativistically covariant, massive Lorentz Electrodynamics (LED) is presented in which the bare particle has a finite positive bare rest mass and moment of inertia. The particle&#39;s electromagnetic self-interaction renormalizes its mass and spin. Most crucially, the renormalized particle is a soliton: after any scattering process its rest mass and

Sen Cheng, Scott Pratt

A method is presented to include quantum corrections into the calculation of two-pion correlations for the case where particles originate from resonance decays. The technique uses classical information regarding the space-time points at which resonances are created. By evaluating a simple thermal model, the method is compared to semiclassical techniques that

Frederick M. Walter

The isolated neutron star RX J185635-3754 is the closest known neutron star to the Sun. Based on HST WFPC2 obervations over a 3 year baseline, I report its proper motion (332 +/- 1 mas/yr at a position angle of 100.3 +/- 0.1 degrees) and parallax (16.5 +/- 2.3 mas; 61 pc). This proper motion brings the neutron star from the general vicinity of the Sco-Cen OB

Shin&#39;ichi Nojiri, Sergei D. Odintsov, Sachiko Ogushi

Bosonic sector of d5 gauged supergravity with specific parametrization of full scalar coset is considered (multi-dilaton gravity). Using holographic RG in the form suggested by de Boer-Verlinde-Verlinde the holographic d4 conformal anomaly (in the sector of curvature invariants) is found when bulk potential is not constant. Its comparison with the earlier ca

N. Sh. Izmailian, Chin-Kun Hu

Let f, U and C represent, respectively, the free energy, the internal energy and the specific heat of the critical Ising model on the square M x N lattice with periodic boundary conditions. We find that N f and U are well-defined odd function of 1/N. We also find that ratios of subdominant (N^(-2 i - 1)) finite-size corrections amplitudes for the internal en

R. Brown, O. Mucuk

In general a universal covering of a non connected topological group need not admit a topological group structure such that the covering map is a morphism of topological groups. This result is due to R.L. Taylor (1953). We generalise this result and relate it to the theory of obstructions to group extensions. The methods use: the equivalence between covering

V. L. Kalashnikov

The results of the study of ultra-short pulse generation in continuous-wave Kerr-lens mode-locked (KLM) solid-state lasers with semiconductor saturable absorbers are presented. The issues of extremely short pulse generation are addressed in the frames of the theory that accounts for the coherent nature of the absorber-pulse interaction. We developed an analy

W. Y. Hwang, D. Ahn, S. W. Hwang

We calculate eavesdropper&#39;s optimal information on raw bits in Bennett-Brassard 1984 quantum key distribution (BB84 QKD) and six-state scheme in coherent attacks, using a formula by Lo and Chau [Science 283 (1999) 2050] with single photon assumption. We find that eavesdropper&#39;s optimal information in QKD without public announcement of bases [Phys. Le

Mihir Ranjan Nath, Surajit Sen

The semi-classical solution of the three state system is considered to study the population inversion at and away from resonance. At resonance, it is shown that if the system is initially populated either in the upper or in the lower level, then the population oscillation occurs in a way which is quite different from that if it is initially populated in the

Hans Halvorson

In their well-known argument against the completeness of quantum theory, Einstein, Podolsky, and Rosen (EPR) made use of a state that strictly correlates the positions and momenta of two particles. We prove the existence and uniqueness of the EPR state as a normalized, positive linear functional of the Weyl algebra for two degrees of freedom. We then show th

Ulrich Mohrhoff

What has so far prevented us from decrypting quantum mechanics is the Cookie Cutter Paradigm, according to which the world&#39;s synchronic multiplicity derives from surfaces that carve up space in the manner of three-dimensional cookie cutters. This insidious notion is shown to be rooted in our neurophysiological make-up. An effort is made to liberate the p

E. A. Kuznetsov, V. P. Ruban

A new mechanism of the collapse in hydrodynamics is suggested, due to breaking of continuously distributed vortex lines. Collapse results in formation of the point singularities of the vorticity field $|{\bfΩ}|$. At the collapse point, the value of the vorticity blows up as $(t_0-t)^{-1}$ where $t_0$ is a collapse time. The spatial structure of the collapsin

A. Silverberg, Yu. G. Zarhin

Suppose $\ell$ is a prime number, $\ell >3$, $K$ is a field that is an unramified finite extension of the field $\Q_\ell$ of $\ell$-adic numbers, and $G$ is a finite group that is a semi-direct product of a normal $\ell&#39;$-subgroup $H$ and a cyclic $\ell$-group $L$. Suppose that the group algebra $K[H]$ is decomposable. If there exists an embedding of $G$

Jaume Llibre, Jorge Vitorio Pereira

We define four different kinds of multiplicity of an invariant algebraic curve for a given polynomial vector field and investigate their relationships. After taking a closer look at the singularities and at the line of infinity, we improve the Darboux theory of integrability using these new notions of multiplicity.

Jorge Vitorio Pereira

We show that a generic vector field on an affine space of positive characteristic admits an invariant algebraic hypersurface. This contrast with Jouanolou&#39;s Theorem that shows that in characteristic zero the situation is completely opposite. That is a generic vector field in the complex plane does not admit any invariant algebraic curve.

Yuri G. Zarhin

In his previous paper (Math. Res. Letters 7(2000), 123--132) the author proved that in characteristic zero the jacobian $J(C)$ of a hyperelliptic curve $C: y^2=f(x)$ has only trivial endomorphisms over an algebraic closure of the ground field $K$ if the Galois group $Gal(f)$ of the irreducible polynomial $f(x) \in K[x]$ is either the symmetric group $S_n$ or

Morris W. Hirsch, Alan Weinstein

We show that every real analytic action of a connected supersoluble Lie group on a compact surface with nonzero Euler characteristic has a fixed point. This implies that E. Lima&#39;s fixed point free $C^{\infty}$ action on $S^2$ of the affine group of the line cannot be approximated by analytic actions. An example is given of an analytic, fixed point free a

Christopher P. Herzog, Igor R. Klebanov

We study the case of open string theory on a D1-brane in a critical electric field. It was argued in hep-th/0006085 that the massless open string modes of this theory decouple from the massive modes, corresponding to a decoupling of the U(1) degrees of freedom in the U(N) gauge theory dual. To provide further support for the decoupling, we present several ex

P. M. Cowdall

We show that a generalised reduction of D=10 IIB supergravity leads, in a certain limit, to a maximally extended SO(2) gauged supergravity in D=9. We show the scalar potential of this model allows both Minkowski and a new type of domain wall solution to the Bogomol&#39;nyi equations. We relate these vacua to type IIB D-branes.

Bianca L. Cerchiai, Bruno Zumino

A left-unilateral matrix equation is an algebraic equation of the form $$ a_0+a_1 x+a_2 x^2+... +a_n x^n=0 $$ where the coefficients $a_r$ and the unknown $x$ are square matrices of the same order and all coefficients are on the left (similarly for a right-unilateral equation). Recently certain perturbative solutions of unilateral equations and their propert

S. M. H. Wong

Recent advances in our understanding of the higher-wave quarkonia have generated much interests in quarkonium physics. However most are devoted to inclusive decays and productions. Experimental data of several two-body exclusive decay channels of P-wave charmonia such as ππand p \bar p are available and some have recently been re-measured by the BES collabor

P. Aurenche

We discuss the production of real or virtual photons in a quark-gluon plasma.

Vadim Apalkov, Tapash Chakraborty

A quantum cascade laser where the quantum wells in the active regions are replaced by quantum dots with their atom-like discrete energy levels is an interesting system to study novel features in optical spectroscopy. We study structures suitable for diagonal lasing transitions in coupled dots, and vertical lasing transitions in a single dot, in the active re

U. S. Schwarz, S. A. Safran

Effective pair potentials for hollow nanoparticles like the ones made from carbon (fullerenes) or metal dichalcogenides (inorganic fullerenes) consist of a hard core repulsion and a deep, but short-ranged, van der Waals attraction. We investigate them for single- and multi-walled nanoparticles and show that in both cases, in the limit of large radii the inte

V. M. Apalkov, Tapash Chakraborty

The luminescence spectra of a quantum cascade laser in a strong magnetic field is influenced significantly by the presence of disorder (charged or neutral) in the system. An externally applied magnetic field parallel to the electron plane causes a red shift of the luminescence peak in the absence of any disorder potential. Our results indicate that the disor