May 1998 arXiv papers — page 10

J. -Q. Liang, H. J. W. Mueller-Kirsten, D. K. Park, F. Zimmerschied

Some models allowing explicit calculation of periodic instantons and evaluation of their action are studied with regard to transitions from classical to quantum behaviour as the temperature is lowered and tunneling sets in. It is shown that (beyond a critical value of a coupling) the spin system considered acquires a first order transition as a result of the

F. Alberici-Kious, J. -P. Bouchaud, L. F Cugliandolo, P. Doussineau

The aging behaviour of the a.c. susceptibility of randomly substituted K$_{1-x}$Li$_x$Ta0$_3$ crystals reveals marked differences with spin-glasses in that cooling rate effects are very important. The response to temperature steps (including temperature cycles) was carefully studied. A model based on thermally activated domain growth accounts for all the exp

O. Biham, E. Milshtein, S. Solomon

The symmetry properties which determine the critical exponents and universality classes in conservative sandpile models are identified. This is done by introducing a set of models, including all possible combinations of abelian vs. non-abelian, deterministic vs. stochastic and isotropic vs. anisotropic toppling rules. The universality classes are determined

S. Y. Savrasov

A variational formulation of the time--dependent linear response based on the Sternheimer method is developed in order to make practical ab initio calculations of dynamical spin susceptibilities of solids. Using gradient density functional and a muffin-tin-orbital representation, the efficiency of the approach is demonstrated by applications to selected magn

Andrea De Martino

We introduce an analytically solvable model for a fragmented object that, despite of a low degree of randomness and of the extreme simplicity of the breaking process, displays non self-averaging effects in its thermodynamic limit.

Louis Felix Feiner, Andrzej M. Oles, Jan Zaanen

The Kugel-Khomskii model, the simplest model for orbital degenerate magnetic insulators, exhibits a zero temperature degeneracy in the classical limit which could cause genuine quantum disorder. Khaliullin and Oudovenko [Phys. Rev. B 56, R14 243 (1997)] suggested recently that instead a particular classical state could be stabilized by quantum fluctuations.

Dirk Helbing

The movement of pedestrians is supposed to show certain regularities which can be best described by an ``algorithm'' for the individual behavior and is easily simulated on computers. This behavior is assumed to be determined by an intended velocity, by several attractive and repulsive effects and by fluctuations. The movement of pedestrians is depend

Li-Zhi Fang, Zu-Gang Deng, Xiao-Yang Xia

We present an investigation of the scale-dependence of bias described by the linear model: $(δρ({\bf x})/\barρ)_{g} = b (δρ(x)/\barρ)_{m}$, $b$ being the bias parameter, and $ρ({\bf x})_{g}$ and $ρ({\bf x})_{m}$ are the galaxy number density and mass density, respectively. Using a discrete wavelet decomposition, we show that the behavior of bias scale-depend

R. A. Remillard, E. H. Morgan

The Galactic microquasars GRS1915+105 and GRO J1655-40 were targets for dedicated monitoring programs with RXTE throughout 1996 and 1997. We review recent results with particular attention to the X-ray QPOs seen in these sources. We confirm the reappearance of 67 Hz oscillations in GRS1915+105 in several different spectral states. Six intervals, each of 1 to

Y. N. Efremov, B. G. Elmegreen, P. W. Hodge

Gamma Ray Burst (GRB) explosions are powerful and frequent enough to make kiloparsec-size shells and holes in the interstellar media of spiral galaxies. The observations of such remnants are summarized. Several observed shells contain no obvious central star clusters and could be GRB remnants, but sufficiently old clusters that could have formed them by supe

C. Charbonnel, J. D. do Nascimento

We recall the current status of the long-standing 3He problem, and its possible connection with chemical anomalies on the red giant branch. In this context, we collect in the literature all the available observations of the carbon isotopic ratio in field and cluster giant stars. Using the HIPPARCOS parallaxes, we get constraints on the evolutionary status of

S. Ilijic, M. Rosandic, D. Dominis, M. Planinic

Since Baschek & Slettebak (1988) drew attention to the similarity between the abundance pattern of lambda Boo stars and that of Vega, there has been a long debate whether Vega should be listed among the chemically peculiar stars of lambda Boo type. We performed an elemental abundance analysis using a high dispersion spectrum in the optical region, and confir

S. Hubrig, W. Berghoefer, G. Mathys

In the ROSAT all-sky survey 11 HgMn stars were detected as soft X-ray emitters (Berghoefer, Schmitt & Cassinelli 1996). Prior to ROSAT, X-ray observations with the Einstein Observatory had suggested that stars in the spectral range B5-A7 are devoid of X-ray emission. Since there is no X-ray emitting mechanism available for these stars (also not for HgMn star

Yu. V. Glagolevskij, E. Gerth, G. Hildebrandt, G. Scholz

We search for a relation between the published distributions of different elements and the calculated magnetic field structure, following from a dipole-quadrupole configuration, of the CP2 star CU Vir. The highest concentration of individual chemical elements on the stellar surface coincides obviously with the regions of the highest values of the magnetic fi

U. Lisenfeld, P. Alexander, G. G. Pooley, T. Wilding

We present new radio continuum data at 4 frequencies on the supermassive, peculiar galaxy NGC 1961. These observations allow us to separate the thermal and the nonthermal radio emission and to determine the nonthermal spectral index distribution. This spectral index distribution in the galactic disk is unusual: at the maxima of the radio emission the synchro

Yu. V. Glagolevskij, E. Gerth, G. Hildebrandt, H. Lehmann

We investigate the radial velocity and the magnetic field of the CP star alpha^2 CVn. The observed variation of the magnetic field is compared with that of our model. We search for a relation between the magnetic field and the distribution of the chemical elements. The period in the radial velocities is constant over a time interval of about 100 years.

E. Gerth, Yu. V. Glagolevskij

The surface structure of the magnetic field in stars is one part of the information about the surface inhomogeneities like brightness, movement or chemical composition, which is contained in the integral radiation flux but distorted beyond recognition by losses of information on the topographical arrangement over the surface because of convolution processes

V. G. Elkin

Two types of stars are known to have strong, large scale magnetic fields: the main sequence Ap stars and the magnetic white dwarfs. This suggest that the former might be the progenitors of the latter. In order to test this idea, I have carried out a search for large scale magnetic fields in stars with evolutionary states which are intermediate, i.e. in Horiz

D. A. Bohlender, J. -F. Gonzalez, J. M. Matthews

We have completed a high-resolution, high-signal-to-noise, spectroscopic survey of the northern members of the peculiar lambda Boo stars in order to investigate the frequency of the incidence of nonradial pulsation (NRP) in these metal-deficient stars. Of 18 objects observed, 9 show conclusive evidence of NRP, which suggests that pulsation instability is a c

S. M. Andrievsky, I. V. Chernyshova, V. G. Klochkova, V. E. Panchuk

High-resolution and high S/N CCD spectra were analyzed to determine accurate LTE abundances in four lambda Boo stars: pi^1 Ori, 29 Cyg, HR 8203 and 15 And. In general, 14 chemical elements were investigated. The main results are the following: all stars have a strong deficiency of the majority of investigated metals. Oxygen exhibits a moderate deficiency. Th

R. A. Remillard

Highlights from the RXTE All Sky Monitor (ASM) during 1996 and 1997 are reviewed with particular attention to X-ray transients. The ASM has detected 117 sources. These include 12 recurrent transients and 10 new X-ray sources, some of which began their outbursts before the launch of RXTE. The majority of the outburst profiles are strikingly different from the

Barbara Drossel

A model for large-scale evolution recently introduced by Amaral and Meyer is studied analytically and numerically. Species are located at different trophic levels and become extinct if their prey becomes extinct. It is proved that this model is self-organized critical in the thermodynamic limit, with an exponent 2 characterizing the size distribution of exti

Efrain J. Ferrer, Vivian de la Incera

In this work we study the dynamical generation of a fermion mass induced by a constant and uniform external magnetic field in an Abelian gauge model with a Yukawa term. We show that the Yukawa coupling not only enhances the dynamical generation of the mass, but it substantially decreases the magnetic field required for the mass to be generated at temperature

Shailesh Chandrasekharan

Lattice QCD using fermions whose Dirac operator obeys the Ginsparg-Wilson relation, is perhaps the best known formulation of QCD with a finite cutoff. It reproduces all the low energy QCD phenomenology associated with chiral symmetry at finite lattice spacings. In particular it explains the origin of massless pions due to spontaneous chiral symmetry breaking

Changrim Ahn, Chaiho Rim

In this paper we study the boundary effects for off-critical integrable field theories which have close analogs with integrable lattice models. Our models are the $SU(2)_{k}\otimes SU(2)_{l}/SU(2)_{k+l}$ coset conformal field theories perturbed by integrable boundary and bulk operators. The boundary interactions are encoded into the boundary reflection matri

Steen Hannestad, Georg Raffelt

The existence of low-mass sterile neutrinos is suggested by the current status of solar and atmospheric neutrinos together with the LSND experiment. In typical four-flavor scenarios, neutrinos would contribute to a cosmic hot dark matter component and to an increased radiation content at the epoch of matter-radiation equality. These effects leave their impri

A . N. Ivanov, M. Nagy, N. I. Troitskaya

We suggest an effective quark model for low-lying baryon octet and decuplet motivated by QCD with a linearly rising confinement potential incorporating the extended Nambu-Jona-Lasinio (ENJL) model with linear realization of chiral U(3)XU(3) symmetry. Baryons are considered as external heavy states coupled to local three-quark currents with fixed spinorial st

Philip Pearle

In an informal way I review collapse models and my part in constructing them, and I recall some encounters with Abner Shimony. In particular, I address the question of the nature of spacetime reality in collapse models, stimulated by Abner's criticism of the "tail" possessed by statevectors in such models.

Philip Pearle

We emphasize that standard quantum theory (SQT) is incomplete because it doesn't describe what is experimentally observed, namely events, nor does it satisfactorily define the circumstances under which events may occur. Simple models are given (all of which have the same density matrix evolution) to illustrate schemes which claim to complete SQT. It is s

R. Abela, J. Bagaturia, W. Bertl, R. Engfer

A new experiment has been set up at the Paul Scherrer Institut to search for muonium to antimuonium conversion. No event was found to fulfil the requested signature which consists of the coincident detection of both constituents of the antiatom in its decay. Assuming an effective (V-A)$\times$(V-A) type interaction an improved upper limit is established for

Hyungju Park

This paper is withdrawn. The current main theorem can be proved by using a simple field theory. The main theorem is to placed by another theorem, shortly.

Beverly K. Berger, David Garfinkle, James Isenberg, Vincent Moncrief

A longstanding conjecture by Belinskii, Khalatnikov, and Lifshitz that the singularity in generic gravitational collapse is spacelike, local, and oscillatory is explored analytically and numerically in spatially inhomogeneous cosmological spacetimes. With a convenient choice of variables, it can be seen analytically how nonlinear terms in Einstein's equa

T. P. Singh

Gamma-ray bursts are believed to result from the coalescence of binary neutron stars. However, the standard proposals for conversion of the gravitational energy to thermal energy have difficulties. We show that if the merger of the two neutron stars results in a naked singularity, instead of a black hole, the ensuing quantum particle creation can provide the

Tobias Gleim, Walter Kob, Kurt Binder

Using molecular dynamics computer simulations we investigate how the relaxation dynamics of a simple supercooled liquid with Newtonian dynamics differs from the one with a stochastic dynamics. We find that, apart from the early beta-relaxation regime, the two dynamics give rise to the same relaxation behavior. The increase of the relaxation times of the syst

A. M. Rudin, I. L. Aleiner, L. I. Glazman

We study local density of electron states of a two-dimentional conductor with a smooth disorder potential in a non-quantizing magnetic field, which does not cause the standart de Haas-van Alphen oscillations. It is found, that despite the influence of such ``classical'' magnetic field on the average electron density of states (DOS) is negligibly smal

Nils Andersson, Kostas Kokkotas, Bernard F. Schutz

A newly discovered instability in rotating neutron stars, driven by gravitational radiation reaction acting on the stars' $r$-modes, is shown here to set an upper limit on the spin rate of young neutron stars. We calculate the timescales for growth of linear perturbations due to gravitational radiation reaction, and for dissipation by shear and bulk visc

I. Horvath

Two classes of Gamma Ray Bursts have been identified so far, characterized by T_90 durations shorter and longer than approximately 2 seconds. We show here that the BATSE 3B data allow a good fit with three Gaussian distributions in log T_90. The chi^2 statistic indicates a 40 % probability for two Gaussians, whereas the three-Gaussian fit probability is 98 %

Joshua S. Bloom, Steinn Sigurdsson, Onno R. Pols

We find the distribution of coalescence times, birthrates, spatial velocities, and subsequent radial offsets of coalescing neutron stars (NSs) in various galactic potentials accounting for large asymmetric kicks introduced during a supernovae. The birthrates of bound NS-NS binaries are quite sensitive to the magnitude of the kick velocities but are, neverthe

S. Boldyrev

The randomly driven Navier-Stokes equation without pressure in d-dimensional space is considered as a model of strong turbulence in a compressible fluid. We derive a closed equation for the velocity-gradient probability density function. We find the asymptotics of this function for the case of the gradient velocity field (Burgers turbulence), and provide a n

Liliana Arrachea, A. A. Aligia

We analyze the possible existence of a superconducting state in a background with long-range antiferromagnetism. We consider a generalized Hubbard model with nearest-neighbor correlated hopping in a square lattice. Near half filling, the model exhibits a d-wave-Bardeen-Cooper-Schrieffer (BCS) solution in the paramagnetic state. The superconducting solution w

Thomas Krajewski, Raimar Wulkenhaar

We reinvestigate Kreimer's Hopf algebra structure of perturbative quantum field theories with a special emphasis on overlapping divergences. Kreimer first disentangles overlapping divergences into a linear combination of disjoint and nested ones and then tackles that linear combination by the Hopf algebra operations. We present a formulation where the Ho

A. A. Penin, A. A. Pivovarov

We present the next-to-next-to-leading order relation between the moments of the $Υ$ system spectral density and the inclusive $B$-meson semileptonic width. The perturbative series for the width as an explicit function of the moments is well convergent in three consequent orders in the strong coupling constant that provides solid and accurate theoretical est

E877 Collaboration, J. Barrette, R. Bellwied, S. Bennett

Directed flow of deuterons, tritons, $^3$He, and $^4$He is studied in Au+Au collisions at a beam momentum of about 10.8 $A$ GeV/c. Flow of all particles is analyzed as a function of transverse momentum for different centralities of the collision. The directed flow signal, $v_1(p_t)$, is found to increase with particle mass. This mass dependence is strongest

M. Dakna, J. Clausen, L. Knoll, D. -G. Welsch

Preparation of Schrödinger-cat-like states via conditional output measurement on a beam splitter is studied. In the scheme, a mode prepared in a squeezed vacuum is mixed with a mode prepared in a Fock state and photocounting is performed in one of the output channels of the beam splitter. In this way the mode in the other output channel is prepared in a Schr

Viktor Yakhontov, Klaus Jungmann

We present the results of the light-shift calculations in the ns-states of hydrogenicsystems in the presence of a weak laser field. This is done by means of analytical calculations of the scalar dynamic polarizabilities (DP) of the corresponding levels. In contrast to the usual technique, 1.e. by solving certain inhomogeneous differential equation. As a resu

M. Boileau, J. Porti

We give a complete proof of Thurston's Orbifold Theorem for very good 3-orbifolds of cyclic type. An orbifold is said to be very good when it has a finite cover which is a manifold. A 3-orbifold is of cyclic type if the singular set is a non-empty 1-manifold transverse to the boundary.

Michael Farber, Vladimir Turaev

In this paper we define a Poincaré-Reidemeister scalar product on the determinant line of the cohomology of any flat vector bundle over a closed orientable odd-dimensional manifold. It is a combinatorial "torsion-type" invariant which refines the PR-metric, introduced earlier by the first author, and contains an additional sign or phase information.

L. Ya. Glozman

In the low-energy regime light and strange baryons should be considered as systems of constituent quarks with confining interaction and a chiral interaction that is mediated by Goldstone bosons as well as by vector and scalar mesons. The flavor-spin structure and sign of the short-range part of the spin-spin force reduces the $SU(6)_{FS}$ symmetry down to $S

A. Udalski

We analyze the mean luminosity of three samples of field RRab Lyr stars observed in the course of the OGLE microlensing experiment: 73 stars from the Galactic bulge and 110 and 128 stars from selected fields in the LMC and SMC, respectively. The fields are the same as in the recent distance determination to the Magellanic Clouds with the red clump stars meth

Yoshiaki Taniguchi, Yasuhiro Shioya

It has been often considered that the dissipative collapse caused by a merger of two gas-rich galaxies is responsible for the intense nuclear starbursts or the nonthermal quasar activity in ultraluminous infrared galaxies due to the efficient fueling induced by it. It is also widely known that Ultraluminous Infrared Galaxies (ULIGs) are often found in mergin

B. T. Soifer, G. Neugebauer, M. Franx, K. Matthews

Near-infrared imaging and spectroscopy have been obtained of the gravitationally lensed galaxy at z=4.92 discovered in HST images by Franx et al. (1997). Images at 1.2, 1.6 and 2.2 microns show the same arc morphology as the HST images. The spectrum with resolution λ/ Δλ~ 70 shows no emission lines with equivalent width stronger than 100 A in the rest frame

Amalie Frischknecht

The stability of a long cylindrical domain in a phase-separating binary fluid in an external shear flow is investigated by linear stability analysis. Using the coupled Cahn-Hilliard and Stokes equations, the stability eigenvalues are derived analytically for long wavelength perturbations, for arbitrary viscosity contrast between the two phases. The shear flo

A. Fayyazuddin, M. Spalinski

Maldacena's duality between conformal field theories and supergravity is applied to some conformal invariant models with 8 supercharges appearing in the F-theory moduli space on a locus of constant coupling. This includes Sp(2N) gauge theories describing the worldvolume dynamics of D3-branes in the presence of D7-branes and an orientifold plane. Other ex

A. V. Radyushkin

Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive meson electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements < p&#39;| O(0,z) | p > of quark and gluon light-cone operators. In our previous papers we use

S. Abdullin, M. Dubinin, V. Ilyin, D. Kovalenko

We discuss the SM Higgs discovery potential of LHC in the reaction $pp\to H+ jet\toγγ+jet$ when the jet is observed at sufficiently high $E_t$ to be reliably identified. We conclude that this channel gives promising discovery possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation at a low luminosity. With 30 fb$^{-1}$ of accumulated d

Chopin Soo

We show from first principles, using explicitly invariant Pauli-Villars regularization of chiral fermions, that the Nieh-Yan form does contribute to the Adler-Bell-Jackiw (ABJ) anomaly for spacetimes with generic torsion, and comment on some of the implications. There are a number of interesting and important differences with the usual ABJ contributions in t

F. Göhmann, A. G. Izergin, V. E. Korepin, A. G. Pronko

We consider the one-dimensional delta-interacting electron gas in the case of infinite repulsion. We use determinant representations to study the long time, large distance asymptotics of correlation functions of local fields in the gas phase. We derive differential equations which drive the correlation functions. Using a related Riemann-Hilbert problem we ob

Guillermo Abramson, Damian Zanette

We analyze purely competitive many-species Lotka-Volterra systems with random interaction matrices, focusing the attention on statistical properties of their asymptotic states. Generic features of the evolution are outlined from a semiquantitative analysis of the phase-space structure, and extensive numerical simulations are performed to study the statistics

Tamas Hausel

In this paper we consider the topological side of a problem which is the analogue of Sen&#39;s S-duality testing conjecture for Hitchin&#39;s moduli space of rank 2 stable Higgs bundles of fixed determinant of odd degree over a Riemann surface. We prove that all intersection numbers in the compactly supported cohomology vanish, i.e. &#34;there are no topolog

F. R. Klinkhamer

Certain (3+1)-dimensional chiral non-Abelian gauge theories have been shown to exhibit a new type of global gauge anomaly, which in the Hamiltonian formulation is due to the fermion zero-modes of a Z-string-like configuration of the gauge potential and the corresponding spectral flow. Here, we clarify the relation between this Z-string global gauge anomaly a

M. Vänttinen, L. Mankiewicz

We consider the exclusive production of $J/ψ$ mesons in polarized virtual-photon--proton collisions. We derive helicity amplitudes for the dominant subprocess $γ^* g \to J/ψg$ and show that polarization asymmetries vanish in the case of collinear scattering. Thus, contrary to what has been suggested earlier, this process is not a good probe of the polarized

Blazenka Melic

Using a modified perturbative approach that includes the Sudakov resummation and transverse degrees of freedom we analyze the penguin-induced $B^{-} \to π^{-}ϕ$ decay by applying the next-to-leading order effective weak Hamiltonian. The modified perturbative method enables us to include nonfactorizable contributions and to control virtual momenta appearing i

D. A. Head, G. J. Rodgers

We introduce a model for granular avalanching which exhibits both stretched exponential and power law avalanching over its parameter range. Two modes of transport are incorporated, a rolling layer consisting of individual particles and the overdamped, sliding motion of particle clusters. The crossover in behaviour observed in experiments on piles of rice is

M. Billo&#39;, P. Di Vecchia, M. Frau, A. Lerda

We use different techniques to analyze the system formed by a D0 brane and a D6 brane (with background gauge fields) in relative motion. In particular, using the closed string formalism of boosted boundary states, we show the presence of a term linear in the velocity, corresponding to the Lorentz force experienced by the D0 brane moving in the magnetic backg

Heiko Pelzer, Thomas Strobl

We extend the classical integrability of the CGHS model of 2d dilaton gravity [1] to a larger class of models, allowing the gravitational part of the action to depend more generally on the dilaton field and, simultaneously, adding fermion- and U(1)-gauge-fields to the scalar matter. On the other hand we provide the complete solution of the most general dilat

M. Biehl, E. Schloesser, M. Ahr

Equilibrium statistical physics is applied to layered neural networks with differentiable activation functions. A first analysis of off-line learning in soft-committee machines with a finite number (K) of hidden units learning a perfectly matching rule is performed. Our results are exact in the limit of high training temperatures. For K=2 we find a second or

A. Lambrecht, M. T. Jaekel, S. Reynaud

We calculate the photon emission of a high finesse cavity moving in vacuum. The cavity is treated as an open system. The field initially in the vacuum state accumulates a dephasing depending on the mirrors motion when bouncing back and forth inside the cavity. The dephasing is not linearized in our calculation, so that qualitatively new effects like pulse sh

Y. P. Jing

An accurate fitting formula is reported for the two-point correlation function of the dark matter halos in hierarchical clustering models, It is valid for the the linearly clustering regime, and its accuracy is about 10% in the correlation amplitude for the halos with mass M greater than 1/100 -- 1/1000 of the characteristic non-linear mass M_c. The result i

V. P. Maslov, O. Yu. Shvedov

The semiclassical theory for the large-N field models is developed from an unusual point of view. Analogously to the procedure of the second quantization in quantum mechanics, the functional Schrodinger large-N equation is presented in a third-quantized form. The third-quantized creation and annihilation operators depend on the field $ϕ({\bf x})$. If the coe

X. -H. Guo, A. W. Thomas, A. G. Williams

In the heavy quark limit, the heavy baryons ω_{Q}^{(*)} (ωcould be Σ, Ξor Ωand Q=b or c) are regarded as composed of a heavy quark and an axial vector, light diquark with good spin and isospin quantum numbers. Based on this diquark picture we establish the Bethe-Salpeter (B-S) equation for ω_{Q}^{(*)} in the limit where the heavy quark has infinite mass, m_Q

The MOA Collaboration

We report optical photometry and HI synthesis observations of the southern edge-on S_c,d galaxy IC5249. The observations were carried out primarily to determine if IC5249 has a red halo surrounding it similar to the halo that has been recently found surrounding the northern edge-on galaxy NGC5907. The galaxy IC5249 is almost perfectly edge-on, and it shows n

Henry P. Stapp

A recent proof, couched in the symbolic language of modal logic, shows that a well-defined formulation of the question posed in the title is answered affirmatively. In a paper with the same title Unruh has tried in various ways to translate the symbolic proof into normal prose, and has claimed that the proof must fail in some way or another. A correct transl

Lars M. Johansen

The density matrix of a nonrelativistic wave-packet in an arbitrary, one-dimensional and time-dependent potential can be reconstructed by measuring hydrodynamical moments of the Wigner distribution. An n-th order Taylor polynomial in the off-diagonal variable is obtained by measuring the probability distribution at n+1 discrete time values.

S. N. Molotkov

A quantum teleportation scheme based on the EPR-pair entangled with respect to the ``energy+time&#39;&#39; variables is proposed. Teleportation of the multimode state of a single-photon wave packet is considered.

V Yakhontov, R. Santra, K. Jungmann

We present ionization probability and line shape calculations for the two-step 3-photon ionization process, $1S \stackrel{2\hbar ω}{\longrightarrow}2S \stackrel{\hbar ω}{\longrightarrow}εP $, of the ground state of hydrogenic atoms in a non-monochromatic laser field with a time--dependent amplitude. Within the framework of a three--level model, the {\it AC S

E. Persson, T. Gorin, I. Rotter

Resonance trapping appears in open many-particle quantum systems at high level density when the coupling to the continuum of decay channels reaches a critical strength. Here a reorganization of the system takes place and a separation of different time scales appears. We investigate it under the influence of additional weakly coupled channels as well as by ta

H. Merlitz, D. Pelte

The time dependent Schrödinger equation for $π^+$--$π^-$ pairs, which are emitted from the interaction zone in relativistic nuclear collisions, is solved using wavepacket states. It is shown that the Coulomb enhancement in the momentum correlation function of such pairs is smaller than obtained in earlier calculations based on Coulomb distorted plane waves.

J. -P. Eckmann, C. E. Wayne

We extend the invariant manifold method for analyzing the asymptotics of dissipative partial differential equations on unbounded spatial domains to treat equations in which the linear part has order greater than two. One important example of this type of equation which we analyze in some detail is the Cahn-Hilliard equation. We analyze the marginally stable

H. J. Borchers, J. Yngvason

For a quantum field in a thermal equilibrium state we discuss the group generated by time translations and the modular action associated with an algebra invariant under half-sided translations. The modular flows associated with the algebras of the forward light cone and a space-like wedge admit a simple geometric description in two dimensional models that fa

Krzysztof Ciesielski, Saharon Shelah

The goal of this note is to construct a uniformly antisymmetric function f:R-> R with a bounded countable range. This answers Problem 1(b) of Ciesielski and Larson. (See also list of problems in Thomson and Problem 2(b) from Ciesielski&#39;s survey.) A problem of existence of uniformly antisymmetric function f:R-> R with finite range remains open.

Menachem Kojman, Saharon Shelah

We give an elementary proof of the fact that regressive Ramsey numbers are Ackermannian. This fact was first proved by Kanamori and McAloon with mathematical logic techniques.

Mirna Džamonja, Saharon Shelah

Suppose that $λ=λ^{<λ} \ge\aleph_0$, and we are considering a theory $T$. We give a criterion on $T$ which is sufficient for the consistent existence of $λ^{++}$ universal models of $T$ of size $λ^+$ for models of $T$ of size $\leλ^+$, and is meaningful when $2^{λ^+}>λ^{++}$. In fact, we work more generally with abstract elementary classes. The criterion for

Tomek Bartoszynski, Saharon Shelah

A set X subseteq R is strongly meager if for every measure zero set H, X+H not= R. Let SM denote the collection of strongly meager sets. We show that assuming CH, SM is not an ideal.

John Truss, Saharon Shelah

A study is carried out of the elementary theory of quotients of symmetric groups in a similar spirit to [Sh:24]. Apart from the trivial and alternating subgroups, the normal subgroups of the full symmetric group S(mu) on an infinite cardinal mu are all of the form S_kappa(mu)= the subgroup consisting of elements whose support has cardinality <kappa for some

Saharon Shelah

We investigate categoricity of abstract elementary classes without any remnants of compactness (like non-definability of well ordering, existence of E.M. models or existence of large cardinals). We prove (assuming a weak version of GCH around lambda) that if K is categorical in lambda, lambda^+, LS(K) <= lambda and 1 <= I(lambda^{++},K)< 2^{lambda^{++}} then

Menachem Magidor, Saharon Shelah

We prove the consistency with ZFC of ``the length of an ultraproduct of Boolean algebras is smaller than the ultraproduct of the lengths&#39;&#39;. Similarly for some other cardinal invariants of Boolean algebras.

D. Gianzo, J. O. Madsen, J. Sanchez Guillen

Following a recent proposal for integrable theories in higher dimensions based on zero curvature, new Lorentz invariant submodels of the principal chiral model in 2+1 dimensions are found. They have infinite local conserved currents, which are explicitly given for the su(2) case. The construction works for any Lie algebra and in any dimension, and it is give

B. Schroer

The main content of this treatise is a new concept in nonperturbative non-Lagrangian QFT which explains and extends the ad hoc constructions in low-dimensional models and incorporates them together with the higher dimensional theories into a new construction method. Thermal and entropical properties, which were hitherto restricted to situations with classica

M. Pernici, M. Raciti, F. Riva

We show that in a Wilsonian renormalization scheme with zero-momentum subtraction point the massless Wess-Zumino model satisfies the non-renormalization theorem; the finite renormalization of the superpotential appearing in the usual non-zero momentum subtraction schemes is thus avoided. We give an exact expression of the beta and gamma functions in terms of

Bert Schroer

The content of this paper is incorporated into hep-th/9805093

B. Geyer, P. M. Lavrov, D. Mülsch

The osp(1,2)-covariant Lagrangian quantization of general gauge theories is formulated which applies also to massive fields. The formalism generalizes the Sp(2)-covariant BLT approach and guarantees symplectic invariance of the quantized action. The dependence of the generating functional of Green&#39;s functions on the choice of gauge in the massive case di

John G. Learned, Sandip Pakvasa, J. L. Stone

We show that the asymmetry in the neutral current events (e.g. Nu N -> Nu N pi^0) can be used to discriminate between Nu_mu - Nu_tau and Nu_mu - Nu_st mixing as being responsible for the atmospheric neutrino anomaly. Specifically, A_N vanishes for Nu_mu - Nu_tau mixing and is about 2/3 A_mu for Nu_mu - Nu_st mixing.

Norberto N. Scoccola, Hans Walliser

We consider the one-loop corrections to the SU(3) skyrmion mass within the bound state soliton approach. We show that the standard SU(3) renormalization scheme is not appropiate within this framework and propose to use an alternative one based on SU(2). For physical meson masses and decay constants the resulting Casimir correction turns out to be rather scal

A. D. Smirnov

The contributions into radiative correction parameters S, T, U from the scalar leptoquarks are calculated in the minimal gauge model with the four-color quark-lepton symmetry. It is shown that the contributions into T and U from the scalar leptoquark doublets are not positive definite. Using the current experimental data on S, T, U the bounds on the scalar l

Yoshiharu Kawamura, Tatsuo Kobayashi, Hitoshi Shimabukuro

We study phenomenological aspects of supersymmetric SO(10) GUTs with sum rules among soft SUSY breaking parameters. In particular, the sum rule related to the stau mass leads to the constraints from the requirements of successful electroweak breaking and the positivity of stau mass squared. The bottom quark mass is also estimated.

K. G. Chetyrkin, J. H. Kühn, A. A. Pivovarov

In this work radiative corrections in the total hadronic decay rate of the tau-lepton and some moments of its differential distributions are studied employing perturbative QCD and the operator product expansion. We calculate quadratic quark mass corrections in the strange mass to the decay rate ratio R_tau to the order O(α_s^3 m^2) and find that they contrib

Francisco Guerrero, Jose Antonio Oller

We have calculated the KK bar --> KK bar scattering amplitude to next to leading order in Chiral Perturbation Theory. Then, making use of a unitarization procedure with one or several coupled channels (ππ, KK bar in our case) we have calculated the ππ--> ππ, ππ--> KK bar and KK bar --> KK bar S and P waves in good agreement with the experiment up to \sqrt{s}

Masahide Yamaguchi, Jun&#39;ichi Yokoyama

We present a formalism to calculate the probability distribution function of a scalar field coarse-grained over some spatial scales with a Gaussian filter at finite temperature. As an application, we investigate the role of subcritical fluctuations in the electroweak phase transition in the minimal standard model. It is concluded that the universe was in a m

X. -H. Guo, A. W. Thomas

We study direct CP violation in the bottom baryon decays \Lambda_b -> f \rho^0 (\omega) -> f\pi^+\pi^- (f=n or \Lambda). It is found that in these decays via \rho-\omega mixing the CP violation could be very large when the invariant mass of the \pi^+\pi^- pair is in the vicinity of the \omega resonance. With a typical value N_c =2 in the factorization approa

F. Abe

We search for new long-lived particles which decay to Z bosons by looking for Z->e+e- decays with displaced vertices. We find no evidence for parent particles of the Z with long lifetimes in 90 pb-1 of data from the CDF experiment at Fermilab. We set a cross section limit as a function of the lifetime of the parent particle for both a generic Z parent and a