January 1997 arXiv papers — page 9

V. Artale, G. Boffetta, A. Celani, M. Cencini

We investigate the spreading of passive tracers in closed basins. If the characteristic length scale of the Eulerian velocities is not very small compared with the size of the basin the usual diffusion coefficient does not give any relevant information about the mechanism of spreading. We introduce a finite size characteristic time $τ(δ)$ which describes the

D. A. Trifonov

Diagonalization of uncertainty matrix and minimization of Robertson inequality for n observables are considered. It is proved that for even n this relation is minimized in states which are eigenstates of n/2 independent complex linear combinations of the observables. In case of canonical observables this eigenvalue condition is also necessary. Such minimizin

Aneesh Manohar

The HQET/NRQCD Lagrangian is computed to order alpha/m^3. The computation is performed using dimensional regularization to regulate the ultraviolet and infrared divergences. The results are consistent with reparametrization invariance to order 1/m^3. Some subtleties in the matching conditions for NRQCD are discussed.

Dmitriy Palatnik

In this paper attention is focused on gravitational sector of the Born--Infeld theory, suggested in quant-ph/9608014. Vacuum equations for gravitational field are derived. The asymptotic for modified Schwarzschild solution is obtained, as a decomposition in parameter $L \approx 10^{-32}$ cm. It is shown, that singularity at $r = 0$ is absent, being replaced

J. Edelmann, G. Piller, W. Weise

We investigate shadowing corrections to the polarized deuteron structure functions g_1^d and b_1. In the kinematic domain of current fixed target experiments we observe that shadowing effects in g_1^d are approximately twice as large as for the unpolarized structure function F_2^d. Furthermore, we find that b_1 is surprisingly large at x < 0.1 and receives d

Shmuel Lifsches, Saharon Shelah

We continue the works of Gurevich-Shelah and Lifsches-Shelah by showing that it is consistent with ZFC that the first-order theory of random graphs is not interpretable in the monadic theory of all chains. It is provable from ZFC that the theory of random graphs is not interpretable in the monadic second order theory of short chains (hence, in the monadic th

Andre de Carvalho

Let f:E -> E be a homeomorphism of the plane E. We define open sets P, called {\em pruning fronts} after the work of Cvitanović, for which it is possible to construct an isotopy H: E x [0,1] -> E with open support contained in the union of f^{n}(P), such that H(*,0)=f(*) and H(*,1)=f_P(*), where f_P is a homeomorphism under which every point of P is wanderin

J. J. P. Veerman, Leo B. Jonker

Local scaling of a set means that in a neighborhood of a point the structure of the set can be mapped into a finer scale structure of the set. These scaling transformations are compact sets of locally affine (that is: with uniformly $α$-Hölder continuous derivatives) contractions. In this setting, without any assumption on the spacing of these contractions s

J. J. P. Veerman

We present a new method to calculate the Hausdorff dimension of a certain class of fractals: boundaries of self-affine tiles. Among the interesting aspects are that even if the affine contraction underlying the iterated function system is not conjugated to a similarity we obtain an upper- and lower-bounds for its Hausdorff dimension. In fact, we obtain the e

G. K. Savvidy

An earlier proposed theory with linear-gonihedhic action for quantum gravity is reviewed. One can consider this theory as a &#34;square root&#34; of classical gravity with a new fundamental constant of dimension one. We demonstrate also, that the partition function for the discretized version of the Einstein-Hilbert action found by Regge in 1961 can be repre

Jiannis Pachos

For slowly varying fields on the scale of the lightest mass the logarithm of the vacuum functional of a massive quantum field theory can be expanded in terms of local functionals satisfying a form of the Schrodinger equation, the principal ingredient of which is a regulated functional Laplacian. We extend a previous work to construct the next to leading orde

F. Scheck

Algebraic Yang-Mills-Higgs theories based on noncommutative geometry have brought forth novel extensions of gauge theories with interesting applications to phenomenology. We sketch the model of Connes and Lott, as well as variants of it, and the model developed by a Mainz-Marseille group, by comparing them in a schematic way. The role of fermion masses and m

J. Barcelos-Neto

We consider the method due to Batalin, Fradkin, Fradkina, and Tyutin (BFFT) that makes the conversion of second-class constraints into first-class ones for the case of nonlinear theories. We first present a general analysis of an attempt to simplify the method, showing the conditions that must be fulfilled in order to have first-class constraints for nonline

Ernest Baver

We present the results for the local state probabilities (LSP) of the solvable lattice models, constructed around rational conformal field theory given by WZW model on $SO(3)_{4 R}=SU(2)_{4 R} / Z_{2}$ together with primary field $ϕ_{1}$(symmetric tensor of degree 2). Some conjectures for the LSP for some higher rank relatives of $A_{n}^{(1)}$ face models ar

Pran Nath, R. Arnowitt

An analysis is given of the effects of non-universal soft SUSY breaking masses in the Higgs sector and in the third generation squark sector, and it is shown that they are highly coupled. Analytic expressions are obtained for their effects on the parameters $μ,m_A$ and on the third generation squark masses. Non-universality effects on dark matter event rates

Alexander L. Kagan, Johan Rathsman

Previously, motivation for enhanced b -> sg from new flavor physics has centered on discrepancies between theory and experiment. Here two experimental hints are considered: (1) updated measurements of the charm multiplicity and BR(Bbar -> X_{ccbars}) at the Upsilon (4S) imply BR(B -> Xnocharm}) \approx 12.4 \pm 5.6 %, (2) the Bbar} -> K- X and Bbar -> K+/K-

G. Couture, M. Frank, H. Konig, M. Pospelov

We calculate the rate of the decay $μ\to eγ$ and the electric dipole moment of the electron in the left-right supersymmetric model when the breaking of parity occurs at a considerably large scale. The low-energy flavor violation in the model originates either from the nonvanishing remnants of the left-right symmetry in the slepton mass matrix or from the dir

S. M. Bilenky, C. Giunti, M. Monteno

We show that, in the framework of a general model with mixing of three Majorana neutrinos and a neutrino mass hierarchy, the results of the Bugey and Krasnoyarsk reactor neutrino oscillation experiments imply strong limitations for the effective Majorana mass |<m>| that characterizes the amplitude of neutrinoless double beta decay. We obtain further limitati

B. O. Kerbikov, D. S. Kuzmenko, Yu. A. Simonov

A new approach to effective theory of quarks in the instanton vacuum is presented. Exact equations for the quark propagator and Lagrangian are derived which contain contributions of all quark modes with known coefficients. The resulting effective Lagrangian differs from the standard one and resembles that of the Nambu-Jona-Lasinio model.

Ulf-G. Meißner, V. Mull, J. Speth, J. W. van Orden

We investigate the role of correlated $πρ$ exchange in the extraction of matrix elements of the strange vector current in the proton. We show that a realistic isoscalar spectral function including this effect leads to sizeably reduced strange vector form factors based on the dispersion--theoretical analysis of the nucleons&#39; electromagnetic form factors.

Dae Sung Hwang, Gwang-Hee Kim

The commonly used Hamiltonian of the chromomagnetic hyperfine splitting is inversely proportional to the product of the masses of two constituent quarks composing the meson. So it is expected to have $(M_{D^*}-M_{D})/(M_{D_s^*}-M_{D_s})$ $\simeq$ $(M_{B^*}-M_{B})/(M_{B_s^*}-M_{B_s})$ $\simeq$ $1.6$, when the constituent quark masses $m_{u,d}=0.33$ GeV and $m

A. Zhuk

Multidimensional cosmological model with the topology M=RxM_1xM_2x...xM_n where M_i (i=1,... ,n) undergo a chain splitting into arbitrary number of compact spaces is considered. It is shown that equations of motion can be solved exactly because they depend only on the effective curvatures and dimensions and &#34;forget&#34; about inner topological structure.

W. Krivan, P. Laguna, P. Papadopoulos

We have developed a numerical method for evolving perturbations of rotating black holes. Solutions are obtained by integrating the Teukolsky equation written as a first-order in time, coupled system of equations, in a form that explicitly exhibits the radial characteristic directions. We follow the propagation of generic initial data through the burst, quasi

John Baker, Chun Biu Li

Recently Abrahams and Cook devised a method of estimating the total radiated energy resulting from collisions of distant black holes by applying Newtonian evolution to the holes up to the point where a common apparent horizon forms around the two black holes and subsequently applying Schwarzschild perturbation techniques . Despite the crudeness of their meth

Paul O&#39;Hara

In this paper a one to one correspondence is established between space-time metrics of general relativity and the wave equations of quantum mechanics. This is done by first taking the square root of the metric associated with a space and from there, passing directly to a corresponding expression in the dual space. It is shown that in the case of a massless p

A. Rosch, A. Schröder, O. Stockert, H. v. Löhneysen

We propose an explanation for the recently observed non-Fermi-liquid behavior of metallic alloys CeCu_{6-x}Au_x: near x=0.1, the specific heat c is proportional to T \ln (T_0/T) and the resistivity increases linearly with temperature T over a wide range of T. These features follow from a model in which three-dimensional conduction electrons are coupled to tw

Yan V. Fyodorov, Dmitry V. Savin, H. -J. Sommers

We analyse universal statistical properties of phase shifts and time delays for open chaotic systems in the crossover regime of partly broken time-reversal invariance. In particular, we find that the distribution of the time delay shows $τ^{-3/2}$ behavior for weakly open systems of any symmetry.

D. Poilblanc, J. Riera, C. A. Hayward, C. Berthier

The magnetic field--driven transition in the spin-Peierls system CuGeO_3 associated with the closing of the spin gap is investigated numerically. The field dependence of the spin dynamical structure factor (seen by inelastic neutron scattering) and of the momentum dependent static susceptibility are calculated. In the dimerized phase (H<H_c), we suggest that

Andreas Wacker

In this book article effects related to the vertical transport in weakly coupled multiple quantum wells are reviewed. A self-contained microscopical model for the calculation of the well-to-well currents without any fittings parameters is presented. The model exhibits the well-known peaks in the current-field relation in quantitative agreement with experimen

J. M. P. Carmelo, F. Guinea, P. D. Sacramento

We find and characterize the instabilities of the repulsive Hubbard chain in a magnetic field by studing all response functions at low frequency ωand arbitrary momentum. The instabilities occur at momenta which are simple combinations of the (U=0) σ=\uparrow ,\downarrow Fermi points, \pm k_{Fσ}. For finite values of the on-site repulsion U the instabilities

D. Cabra, A. Dobry, A. Greco, G. Rossini

We propose a classical constrained Hamiltonian theory for the spin. After the Dirac treatment we show that due to the existence of second class constraints the Dirac brackets of the proposed theory represent the commutation relations for the spin. We show that the corresponding partition function, obtained via the Fadeev-Senjanovic procedure, coincides with

Yong-Jihn Kim

It is shown that the Bogoliubov-de Gennes equations pair the electrons in states which are linear combinations of the normal states. Accordingly, the BCS-like reduction procedure is required to choose a correct pairing. For a homogeneous system, we point out that the kernel of the self-consistency equation derived from the Bogoliubov-de Gennes equations need

L. W. Wong, H. W. Jiang, W. J. Schaff

Gated GaAs/AlGaAs heterostructures were used to determine the low-temperature behavior of the two-dimensional electron gas near filling factor nu=1/2 in the disorder-magnetic-field plane. We identify a line on which sigma_{xy} is temperature independent, has value sigma_{xy}=0.5 (e^{2}/h), and a distinct line on which rho_{xy}=2 (h/e^{2}). The phase boundari

Giorgio Parisi

In this note we present numerical simulations of binary mixtures and we find indications for a thermodynamic transition to a glassy phase. We find that below the transition point the off equilibrium correlation functions and response functions seems to be asymptotically compatible with the relations that were originally derived Cugliandolo Kurchan for genera

Abraham Loeb

Gravitational lensing by a spiral galaxy occurs when the line-of-sight to a background quasar passes within a few kpc from the center of the galactic disk. Since galactic disks are rich in neutral hydrogen, the quasar spectrum will likely be marked by a damped Lyman-alpha absorption trough at the lens redshift. Therefore, the efficiency of searches for gravi

Hugo Martel, Paul R. Shapiro, Steven Weinberg

In theories in which the cosmological constant Lambda takes a variety of values in different ``subuniverses,&#39;&#39; the probability distribution of its observed values is conditioned by the requirement that there must be someone to measure it. This probability is proportional to the fraction of matter which is destined to condense out of the background in

Jerome A. Orosz, Ronald A. Remillard, Charles D. Bailyn, Jeffrey E. McClintock

The All Sky Monitor on the Rossi X-ray Timing Explorer detected an X-ray (2-12 keV) outburst from the black hole binary GRO J1655-40 beginning near April 25, 1996. Optical photometry obtained April 20-24, 1996 shows a steady brightening of the source in B, V, R, and I beginning about six days before the start of the X-ray outburst. The onset of the optical b

R. Henriksen, P. Andre, S. Bontemps

Recent observations suggest that mass ejection and mass accretion both decline significantly with time during early protostellar evolution (Bontemps et al. 1996). In the present paper, we propose that this rapid decay of accretion/ejection activity is a direct result of the non-singular density profiles characterizing pre-collapse clouds. The radial density

B. Link, R. I. Epstein

Variation in the angle $α$ between a pulsar&#39;s rotational and magnetic axes would change the torque and spin-down rate. We show that sudden increases in $α$, coincident with glitches, could be responsible for the persistent increases in spin-down rate that follow glitches in the Crab pulsar. Moreover, changes in $α$ at a rate similar to that inferred for

G. Bertin

We consider a class of fully self-gravitating accretion disks, for which efficient cooling mechanisms are assumed to maintain the disk close to the margin of Jeans instability. For such self-regulated disks the equations become very simple in the outer regions, where the angular momentum convective transport approximately balances the viscous transport. Thes

Axel D. Schwope, Karl-Heinz Mantel, Keith Horne

We present phase-resolved spectroscopy of the bright, eclipsing polar HU Aqr obtained with high time (~30sec) and spectral (1.6 A) resolution when the system was in a high accretion state. The trailed spectrograms reveal clearly the presence of three different line components with different width and radial velocity variation. By means of Doppler tomography

Jordi Miralda-Escude, Martin J. Rees

Recent evidence on the metal content of the high-redshift Lyman alpha forest seen in quasar spectra suggests that an early generation of galaxies enriched the intergalactic medium (IGM) at z ~ 5. We calculate the number of supernovae that need to have taken place to produce the observed metallicity. The progenitor stars of the supernovae should have emitted

Hui Li, James A. Miller

We consider electron acceleration by obliquely propagating fast mode waves in magnetically dominated accretion disk coronae. For low coronal plasma densities, acceleration can exceed Coulomb drag at lower energies and energize electrons out of the thermal background, resulting in a nonthermal tail. The extent of this tail is determined by the balance between

L. Martinet, D. Friedli

With the prime aim of better probing and understanding the intimate link between star formation activity and the presence of bars, a representative sample of 32 non-interacting late-type galaxies with well-determined bar properties has been selected. We show that all the galaxies displaying the highest current star forming activity have both strong and long

A. Kogut, G. Hinshaw, A. J. Banday

Small departures from a homogeneous isotropic spacetime create observable features in the large-scale anisotropy of the cosmic microwave background. We cross-correlate the maps of the cosmic microwave background anisotropy from the Cosmic Background Explorer (COBE) Differential Microwave Radiometers (DMR) 4-year data set with template maps from Bianchi VII_h

Eric Emsellem, Robin Arsenault

We have obtained $V$, $R_c$, $I_c$ HRCAM images and TIGER spectrography of the central region of the peanut galaxy NGC~128. The colour images reveal the presence of a red disc tilted by about 26 degres with respect to the major-axis of the galaxy. This tilted disc is made of dust and gas, as revealed by the 2D TIGER map of the ionized gas distribution. The T

Eric Emsellem, Francoise Combes

We test through stellar N-body simulations some scenarios to explain the dynamics of the peculiar nucleus of the Andromeda galaxy (M~31): although HST observations reveal a double nucleus morphology, the rotation field is almost symmetric around the bulge gravity centre and the velocity dispersion is off-centred. We show that any m=1 perturbation has a very

Axel D. Schwope, Sabine Mengel, Klaus Beuermann

We present phase-resolved spectroscopy of the eclipsing AM Herculis star UZ For obtained when the system was in its low state of accretion. Faint residual Halpha-emission and NaI absorption were used to trace the secondary star and infer its orbital velocity K_2. The measured radial velocity amplitude of NaI K_2 * sin(i) = 285 \pm 50 kmps suggests a low-mass

Axel D. Schwope, Sabine Mengel

We present phase-resolved optical spectroscopy and CCD photometry of the faint eclipsing polar EP Dra (H1907+690). A revised ephemeris is derived which connects all 32000 binary cycles since its discovery by Remillard et al. (1991). We found no difference between spin and and orbital periods of the white dwarf. Changes in the light curve morphology are attri

Axel D. Schwope, Klaus Beuermann

We present phase-resolved spectrophotometric observations of VV Puppis obtained during two different states of accretion. We confirm the detection of cyclotron lines from emission regions at both poles (Wickramasinghe et al. 1989) having significantly different field strength of B_1 ~ 31MG and B_2 ~ 54MG. Our phase-resolved data allowed the detection of phas

Bodo L. Ziegler, Ralf Bender

The correlation between the Mg absorption index and the velocity dispersion (sigma) of local elliptical galaxies is very tight. Because the Mg absorption depends on both metallicity and age of the underlying stellar population the observed Mg-sigma relation constrains the possible variation in metallicity and age for a given velocity dispersion. For a time i

K. Iwamoto, T. R. Young, N. Nakasato, T. Shigeyama

Rayleigh-Taylor (R-T) instabilities in the explosion of SN 1993J are investigated by means of two-dimensional hydrodynamical simulations. It is found that the extent of mixing is sensitive to the progenitor&#39;s core mass and the envelope mass. Because the helium core mass (3 - 4 \ms) is smaller than that of SN 1987A, R-T instabilities at the He/C+O interfa

G. C. McLaughlin, G. M. Fuller

We assess the prospects for attaining steady nuclear flow equilibrium in expanding r-process environments where beta decay and/or neutrino capture determine the nuclear charge-changing rates. For very rapid expansions, we find that weak steady flow equilibrium normally cannot be attained. However, even when neutron capture processes freeze out in such nonequ

Guo-Hong Wu, Ken Kiers, John N. Ng

We demonstrate that polarization measurements in exclusive semileptonic B decays are powerful tools for unraveling non-standard model sources of T-violation. Measurements of the transverse polarization of the tau lepton in the B to D tau nu and B to D* tau nu decays probe separately effective scalar and pseudoscalar CP-violating four-Fermi interactions, wher

Y. Naveh, D. V. Averin, K. K. Likharev

Shot noise in diffusive mesoscopic conductors, at finite observation frequencies $ω$ (comparable to the reciprocal Thouless time $τ_T^{-1}$), is analyzed with an account of screening. At low frequencies, the well-known result $S_I(ω)=2eI/3$ is recovered. This result is valid at arbitrary $ωτ_T$ for wide conductors longer than the screening length. However, a

Xiang-Mao Ding, Bo-Yu Hoy, Liu Zhao

An hbar-deformed Virasoro Poisson algebra is obtained using the Wakimoto realization of the Sugawara operator for the Yangian double DY_\hbar(sl_2)_c at the critical level c=-2.

R. Preuss, W. Hanke, C. Gröber, H. G. Evertz

On the basis of Quantum Monte Carlo simulations of the two-dimensional Hubbard model which cover the doping range from the under- to the over-doped regime, we find that the single-particle spectral weight $A (\vec k,ω)$ qualitatively reproduces both the momentum ($d_{x^2-y^2}$--symmetry) and doping dependence of the pseudogap as found in photoemission experi

Bruce M. Boghosian, Washington Taylor

A general class of discrete unitary models are described whose behavior in the continuum limit corresponds to a many-body Schrodinger equation. On a quantum computer, these models could be used to simulate quantum many-body systems with an exponential speedup over analogous simulations on classical computers. On a classical computer, these models give an exp

Charles H. Bennett, David P. DiVincenzo, John A. Smolin

The quantum analog of the classical erasure channel provides a simple example of a channel whose asymptotic capacity for faithful transmission of intact quantum states, with and without the assistance of a two-way classical side channel, can be computed exactly. We derive the quantum and classical capacities for the quantum erasure channel and related channe

J. M. P. Carmelo, N. M. R. Peres

We introduce the pseudohole and heavy-pseudoparticle operator algebra that generates all Hubbard-chain eigenstates from a single reference vacuum. In addition to the pseudoholes already introduced for the description of the low-energy physics, this involves the heavy pseudoparticles associated with Hamiltonian eigenstates whose energy spectrum has a gap rela

Daniel Gerbal, Gastao B. Lima Neto, Isabel Marquez, Huub Verhagen

We have fitted the surface brightness of a sample of 79 elliptical galaxies pertaining to the Coma cluster of galaxies using the Sersic profile. This model is defined through three primary parameters: scale length (a), intensity (Σ_0), and a shape parameter (ν); physical and astrophysical quantities may be computed from these parameters. We show that correla

Yuri B. Suris

We revisit integrable discretizations for the nonlinear Schrödinger equation due to Ablowitz and Ladik. We demonstrate how their main drawback, the non-locality, can be overcome. Namely, we factorize the non-local difference scheme into the product of local ones. This must improve the performance of the scheme in the numerical computations dramatically. Usin

Dan Pirjol, Tung-Mow Yan

We study the strong interactions of the L=1 orbitally excited baryons with one heavy quark in the framework of the Heavy Hadron Chiral Perturbation Theory. To leading order in the heavy mass expansion, the interaction Lagrangian describing the couplings of these states among themselves and with the ground state heavy baryons contains 46 unknown couplings. We

Guido Altarelli, Richard D. Ball, Stefano Forte, Giovanni Ridolfi

We present a NLO perturbative analysis of all available data on the polarized structure function g_1(x,Q^2) with the aim of making a quantitative test of the validity of the Bjorken sum rule, of measuring α_s, and of deriving helicity fractions. We take particular care over the small x extrapolation, since it is now known that Regge behaviour is unreliable a

Recai Erdem

We find that the local character of field theory requires the parity degree of freedom of the fields to be considered as an additional dicrete fifth dimension which is an artifact emerging due to the local description of space-time. Higgs field arises as the gauge field corresponding to this discrete dimension. Hence the noncommutative geometric derivation o

Bernhard Geiger

Analysing the weak lensing distortions of the images of faint background galaxies provides a means to constrain the mass distribution of cluster galaxies and potentially to test the extent of their dark matter halos as a function of the density of the environment. Here I describe simulations of observational data and present a maximum likelihood method to in

S. N. Nazin, K. A. Postnov

Assuming the observed pulsar velocities to originate during asymmetric collapse of stellar cores, we compute the amplitude of gravitational waves emitted during type II and Ib supernova explosions and their detection rate from within a distance of 30 Mpc. At the rms-level of advanced laser interferometers h ~ 1.0e-22 at frequencies 300-1000 Hz the expected r

M. Tanaka

We have found that supersymmetry (SUSY) in curved space is broken softly. It is also found that Pauli-Villars regularization preserves the remaining symmetry, softly broken SUSY. Using it we computed the one-loop effective potential along a (classical) flat direction in a Wess-Zumino model in de Sitter space. The analysis is relevant to the Affleck-Dine mech

U. Heinz, Q. H. Zhang

We address the question which additional information on the source shape and dynamics can be extracted from three-particle Bose-Einstein correlations. For chaotic sources the true three-particle correlation term is shown to be sensitive to the momentum dependence of the saddle point of the source and to its asymmetries around that point. For partially cohere

L. Borisov, M. B. Halpern, C. Schweigert

We introduce an orbifold induction procedure which provides a systematic construction of cyclic orbifolds, including their twisted sectors. The procedure gives counterparts in the orbifold theory of all the current-algebraic constructions of conformal field theory and enables us to find the orbifold characters and their modular transformation properties.

E. Elizalde, L. Vanzo, S. Zerbini

The multiplicative anomaly associated with the zeta-function regularized determinant is computed for the Laplace-type operators $L_1=-\lap+V_1$ and $L_2=-\lap+V_2$, with $V_1$, $V_2$ constant, in a D-dimensional compact smooth manifold $ M_D$, making use of several results due to Wodzicki and by direct calculations in some explicit examples. It is found that

C. Devchand, Jeremy Schiff

We examine the precise structure of the loop algebra of `dressing&#39; symmetries of the Principal Chiral Model, and discuss a new infinite set of abelian symmetries of the field equations which preserve a symplectic form on the space of solutions.

A. Perez-Garrido, M. J. W. Dodgson, M. A. Moore

We investigate Thomson&#39;s problem of charges on a sphere as an example of a system with complex interactions. Assuming certain symmetries we can work with a larger number of charges than before. We found that, when the number of charges is large enough, the lowest energy states are not those with the highest symmetry. As predicted previously by Dodgson an

Yoji Kohara

It is proved that the nonleptonic decay amplitudes of antitriplet charmed baryons to octet baryons do not depend on the representation of the octet baryons in the quark diagram scheme. Relations among various representations are derived, and correct decay amplitudes of the charmed baryons are given.

Janne Ruostekoski, Juha Javanainen

We study the quantum field theory of light-matter interactions for quantum degenerate atomic gases at low light intensity. We argue that the contact interactions between atoms emerging in the dipole gauge may be ignored. Specifically, they are canceled by concurrent infinite level shifts of the atoms. Our development yields the classic Lorentz-Lorenz local-f

Zurab Kakushadze, S. -H. Henry Tye

Requiring that supersymmetric SU(5) and SU(6) grand unifications in the heterotic string theory must have 3 chiral families, adjoint (or higher representation) Higgs fields in the grand unifiedgauge group, and a non-abelian hidden sector, we construct such string models within the framework of conformal field theory and asymmetric orbifolds. Within this fram

Vadim B. Kuznetsov

We prove separation of variables for the most general (Dn type) periodic Toda lattice with 2x2 Lax matrix. It is achieved by finding proper normalisation for the corresponding Baker-Akhiezer function. Separation of variables for all other periodic Toda lattices associated with infinite series of root systems follows by taking appropriate limits.

Armin Uhlmann

After recalling definition, monotonicity, concavity, and continuity of a channel&#39;s entropy with respect to a state (finite dimensional cases only), I introduce the roof property, a convex analytic tool, and show its use in treating an example. Full proofs and more examples will appear elsewhere. The relation (a la Benatti) to accessible information is me

Martin Treiber, Nandor Eber, Agnes Buka, Lorenz Kramer

We investigated travelling waves appearing as the primary pattern-forming instability in the nematic Phase 5 (Merck) in the planar geometry in order to test the recently developed weak electrolyte model of ac-driven electroconvection [M. Treiber and L. Kramer, Mol. Cryst. Liq. Cryst 261, 311 (1995)]. Travelling waves are observed over the full conductive ran

G. Lazzari, F. V. De Blasio, M. Hjorth-Jensen, Oe. Elgaroey

The coherence length of superfluid neutron matter is calculated from the microscopic BCS wavefunction of a Cooper pair in momentum space making use of the Bonn meson-exchange potential. We find that the coherence length is proportional to the Fermi momentum-to pairing gap ratio, in good agreement with simple estimates used in the literature, and we establish

H. Arenhoevel, G. Kress, R. Schmidt, P. Wilhelm

The Gerasimov-Drell-Hearn sum rule is evaluated for the deuteron by explicit integration up to a photon energy of 550 MeV including contributions from the photodisintegration channel and from coherent and incoherent single pion production as well. The photodisintegration channel converges fast enough in this energy range and gives a large negative contributi

C. Deutsch-Sauermann, B. Friman, W. Noerenberg

We present a unitary and gauge-invariant model with coupled channels, which provides a consistent description of pion photoproduction off nucleons in the E$_{0+}$ channel and eta-meson photoproduction off protons and deuterons. An effective field theory with hadrons and photons is constructed, which includes non-resonant Born terms as well as the S$_{11}$(15

Akihiko Yukie

In this paper, we determine the rational orbit decomposition for two prehomogeneous vector spaces associated with the simple group of type G_2.

Vladimir Shpilrain, Jie-Tai Yu

Let $ K[x, y]$ be the polynomial algebra in two variables over a field $K$ of characteristic $0$. A subalgebra $R$ of $K[x, y]$ is called a retract if there is an idempotent homomorphism (a {\it retraction}, or {\it projection}) $φ: K[x, y] \to K[x, y]$ such that $φ(K[x, y]) = R$. The presence of other, equivalent, definitions of retracts provides several di

Alice Rogers

Conditions which must be satisfied by the gauge-fixing fermion $χ$ used in the BRST quantisation of constrained systems are established. These ensure that the extension of the Hamiltonian by the gauge-fixing term $[Ω, χ]$ (where $Ω$ is the BRST charge) gives the correct path integral. (Lecture given at the conference Constrained Dynamics and Quantum Gravity

L. Alvarez-Gaume, S. F. Hassan

In these notes we attempt to give a pedagogical introduction to the work of Seiberg and Witten on S-duality and the exact results of N=2 supersymmetric gauge theories with and without matter. The first half is devoted to a review of monopoles in gauge theories and the construction of supersymmetric gauge theories. In the second half, we describe the work of

K. Sveshnikov, P. Silaev, I. Cherednikov

A nonperturbative regularization of UV-divergencies, caused by finite discontinuities in the field configuration, is discussed in the context of 1+1-dimensional kink models. The relationship between this procedure and the appearance of &#34;quantum copies&#34; of classical kink solutions is studied in detail and confirmed by conventional methods of soliton q

Vladimir Korepin, Nikita Slavnov

We consider gapless models of statistical mechanics. At zero temperatures correlation functions decay asymptotically as powers of distance in these models. Temperature correlations decay exponentially. We used an example of solvable model to find the formula, which describes long distance and large time asymptotic of correlation function of local fields. The

Mikhail Plyushchay

It is shown that the deformed Heisenberg algebra involving the reflection operator R (R-deformed Heisenberg algebra) has finite-dimensional representations which are equivalent to representations of paragrassmann algebra with a special differentiation operator. Guon-like form of the algebra, related to the generalized statistics, is found. Some applications

C. Codirla, H. Osborn

The role of the conformal group in electrodynamics in four space-time dimensions is re-examined. As a pedagogic example we use the application of conformal transformations to find the electromagnetic field for a charged particle moving with a constant relativistic acceleration from the Coulomb electric field for the particle at rest. We also re-consider the

C. Acerbi

We compute the form factors of exponential operators $e^{kgφ(x)}$ in the two-dimensional integrable Bullough-Dodd model ($a_2^{(2)}$ Affine Toda Field Theory). These form factors are selected among the solutions of general nonderivative scalar operators by their asymptotic cluster property. Through analitical continuation to complex values of the coupling co

J. Barcelos-Neto, W. Oliveira

We use the method due to Batalin, Fradkin, Fradkina, and Tyutin (BFFT) in order to convert second-class into first-class constraints for some quantum mechanics supersymmetric theories. The main point to be considered is that the extended theory, where new auxiliary variables are introduced, has to be supersymmetric too. This leads to some additional restrict

Lee Brekke, Sterrett J. Collins, Tom D. Imbo

We discuss the physics of topological vortices moving on an arbitrary surface M in a Yang-Mills-Higgs theory in which the gauge group G breaks to a finite subgroup H. We concentrate on the case where M is compact and/or nonorientable. Interesting new features arise which have no analog on the plane. The consequences for the quantum statistics of vortices are

I. Antoniadis, J. Ellis, G. K. Leontaris

In this letter, the possible appearance of N=2 supersymmetry at a low energy scale is investigated in the context of unified theories. Introducing mirror particles for all the gauge and matter multiplets of the Minimal Supersymmetric extension of the Standard Model (MSSM), the measured values of sin^2 θ_W and α_3(M_Z) indicate that the N=2 threshold scale M_

Frank Close

The $f_0(1500)$ is identified in three glueball favoured production mechanisms: $p\bar{p}$ annihilation, $ψ\to γf_0$ and Central Production. The production rate for glueballs in $ψ\to γG$ has been quantified and the $f_0(1500)$ is found to be consistent with a glueball - $q\bar{q}$ mixture. We illustrate a remarkable property of central production where kine

K. G. Klimenko, A. S. Vshivtsev

It is shown that in the Nambu -- Jona - Lasinio model at nonzero chemical potential there are two different massive phases with spontaneously broken chiral symmetry. In one of them particle density is identically zero, in another phase it is not equal to zero. The transition between phases is a phase transition of the second order.

Nima Arkani-Hamed, John March-Russell, Hitoshi Murayama

We propose a general scheme for constructing models in which the Standard Model (SM) gauge interactions are the mediators of supersymmetry breaking to the fields in the supersymmetric SM, but where the SM gauge groups couple directly to the sector which breaks supersymmetry dynamically. Despite the direct coupling, the models preserve perturbative unificatio

Thomas W. Baumgarte, Stuart L. Shapiro, Gregory B. Cook, Mark A. Scheel

We present a numerical scheme that solves the initial value problem in full general relativity for a binary neutron star in quasi-equilibrium. While Newtonian gravity allows for a strict equilibrium, a relativistic binary system emits gravitational radiation, causing the system to lose energy and slowly spiral inwards. However, since inspiral occurs on a tim

R. Loll

I review and discuss some recent developments in non-perturbative approaches to quantum gravity, with an emphasis on discrete formulations, and those coming from a classical connection description.

R. Loll

We advocate an alternative description of canonical gravity in 3+1 dimensions, obtained by using as the basic variable a real variant of the usual Ashtekar connection variables on the spatial three-manifold. With this ansatz, no non-trivial reality conditions have to be solved, and the Hamiltonian constraint, though non-polynomial, can be quantized rigorousl