February 1997 arXiv papers — page 6

C J S Clarke

A new concept analogous to global hyperbolicity is introduced, based on test fields. It is shown that the space-times termed here ``curve integrable'' are globally hyperbolic in this new sense, and a plausibility argument is given suggesting that the result applies to shell crossing singularities. If the assumptions behind this last argument are vali

R. A. Arndt, I. I. Strakovsky, R. L. Workman

We have updated our multipole analyses to incorporate new data from the low-energy and delta resonance regions. We note a slight decrease in our estimate of the delta photo-decay amplitudes. This agrees with results found in Compton scattering. Our values are also in good agreement with a previous RPI determination. We have reexamined our determinations of t

S. J. van Enk, J. I. Cirac, P. Zoller

We consider transmission of an (unknown) quantum state between two distant atoms via photons. Based on a quantum-optical realistic model, we define a noisy quantum channel which includes systematic errors as well as errors due to coupling to the environment. We present a protocol that allows one to accomplish ideal transmission by repeating the transfer oper

Thorsten Emig, Kirill Samokhin, Stefan Scheidl

It is shown here that surfaces of high-temperature superconductors are covered by dipole layers. The charge density modulation is induced by the local suppression of the gap function at the surface. This effect is studied in the framework of the Ginzburg-Landau theory and crucially depends on the appropriate boundary conditions. Those are derived from Gor&#3

A. E. Allahverdyan, D. B. Saakian

The weak converse coding theorems have been proved for the quantum source and channel. The results give the lower bound for capacity of source and the upper bound for capacity of channel. The monotonicity of mutual quantum information have also been proved. PACS numbers: 03.65.Bz

Peter Kopietz, Sudip Chakravarty

We calculate the nuclear relaxation rate of oxygen in the undoped quasi two-dimensional quantum Heisenberg antiferromagnet Sr_2CuO_2Cl_2 above the Neel temperature. The calculation is performed at two-loop order with the help of the Dyson-Maleev formulation of the spin-wave expansion, taking all scattering processes involving two and three magnons into accou

Dan Radu Grigore

The geometric Lagrangian theory (of arbitrary order) is based on the analysis of some basic mathematical objects such as: the contact ideal, the (exact) variational sequence, the existence of Euler-Lagrange and Helmholtz-Sonin forms, etc. In this paper we give new and much simpler proofs for the whole theory using Fock space methods. Using these results we g

Chigak Itoi, Yoshinori Sakamoto

We calculate connected correlators in time dependent Gaussian orthogonal and symplectic random matrix ensembles by a diagrammatic method. We obtain averaged one-point Green's functions in the leading order O(1) and wide two-level and three-level correlators in the first nontrivial order by summing over twisted and untwisted planer diagrams.

T. Y. Koo, S. H. Park, K. B. Lee, Y. H. Jeong

Thin films of perovskite manganite La_{0.7}Ca_{0.3}MnO_{3} were grown epitaxially on SrTiO_3(100), MgO(100) and LaAlO_3(100) substrates by the pulsed laser deposition method. Microscopic structures of these thin film samples as well as a bulk sample were fully determined by x-ray diffraction measurements. The unit cells of the three films have different shap

V. I. Man'ko, R. V. Mendes

For Dirac equation, operator-invariants containing explicit time-dependence in parallel to known time-dependent invariants of nonrelativistic Schrödinger equation are introduced and discussed. As an example, a free Dirac particle is considered and new invariants are constructed for it. The integral of motion, which is initial Newton-Wigner position operator,

M. Chaichian, A. Demichev, P. P. Kulish

Different analogs of quasiclassical limit for a q-oscillator which result in different (commutative and non-commutative) algebras of ``classical'' observables are derived. In particular, this gives the q-deformed Poisson brackets in terms of variables on the quantum planes. We consider the Hamiltonian made of special combination of operators (the ana

P. Danielewicz, S. Pratt

Delays associated with elementary interaction processes are investigated. The case of broad resonances is discussed in the context of reaction simulations.

C. A. Bertulani, P. Lotti

At forward angles, and bombarding energies E > 200 MeV, the (p,n) and (n,p) reactions are thought to be directly proportional to the Gamow-Teller transition strengths in the nuclei. Assuming that this relationship also holds for charge exchange induced by high-energy heavy ions, it would be very useful in studies with radioactive beams. Contrary to this expe

Kamil John, Dirk Werner

We show for $2\le p<\infty$ and subspaces $X$ of quotients of $L_{p}$ with a $1$-unconditional finite-dimensional Schauder decomposition that $K(X,\ell_{p})$ is an $M$-ideal in $L(X,\ell_{p})$.

Ernest Schimmerling, W. Hugh Woodin

An optimal extension of the Jensen covering lemma, within the limits imposed by Prikry forcing, is proved. If L[E] is an &#34;iterable&#34; weasel with no measurable cardinals, then either L[E] has &#34;indiscernibles&#34;, or every uncountable set of ordinals is contained in a set in L[E] of the same cardinality. (The terms &#34;iterable&#34; and &#34;indis

William J. Mitchell, Ernest Schimmerling, John R. Steel

A cardinal kappa is countably closed if mu^omega < kappa whenever mu < kappa. Assume that there is no inner model with a Woodin cardinal and that every set has a sharp. Let K be the core model. Assume that kappa is a countably closed cardinal and that alpha is a successor cardinal of K with kappa < alpha < kappa^+. Then cf( alpha ) = kappa. In particular, K

Ernest Schimmerling, John R. Steel

If T is an iteration tree on K and F is a countably certified extender that coheres with the final model of T, then F is on the extender sequence of the final model of T. Several applications of maximality are proved, including: o K computes successors of weakly compact cardinals correctly. o K^c is an iterate of K. o (with Mitchell) If alpha is a cardinal >

Ernest Schimmerling

Square-kappa-finite, the finite family version of weak square, holds at all cardinals kappa in the Mitchell-Steel inner models.

Gary McCartor

To produce an isomorphism between the light-cone and equal-time representations some additional formalism beyond that originally proposed for the light-cone representation may sometimes be required. The additional formalism usually involves zero modes and is most likely to affect delicate, high energy aspects of the solution such as condensates. In this talk

T. Strobl

I present the ``Chern--Simons&#39;&#39; formulation of generalized 2d dilaton gravity, summarize its Hamiltonian quantization (reduced phase space and Dirac quantization) and briefly discuss the statistical mechanical entropy of 2d black holes. Focus is put on the close relation to finite dimensional point particle systems.

Robert Carroll

In a finite zone KdV context we show relations between the duality variables of Faraggi-Matone and those involved in Seiberg-Witten type duality.

Wolfgang Lucha, Michael Moser

Finite quantum field theories may be constructed from the most general renormalizable quantum field theory by forbidding, order by order in the perturbative loop expansion, all ultraviolet-divergent renormalizations of the physical parameters of the theory. The relevant finiteness conditions resulting from this requirement relate all dimensionless couplings

Helmuth Huffel, Gerald Kelnhofer

We propose a generalization of the stochastic gauge fixing procedure for the stochastic quantization of gauge theories where not only the drift term of the stochastic process is changed but also the Wiener process itself. All gauge invariant expectation values remain unchanged. As an explicit example we study the case of an abelian gauge field coupled with t

U. Baur, T. Han, N. Kauer, R. Sobey

The electroweak process $p\bar p \to \ell^\pmνγγ$ is calculated at tree level, including finite W width effects. In order to obtain a gauge invariant amplitude, the imaginary parts of $WWγ$ triangle graphs and $WWγγ$ box diagrams have to be included, in addition to resumming the imaginary contributions to the W polarization. We demonstrate the existence of a

X. Song, J. S. McCarthy, H. J. Weber

The SU(3) symmetric chiral quark model, which describes interactions between quarks, gluons and the Goldstone bosons, explains reasonably well many aspects of the flavor and spin structure of the proton, except for the values of $f_3/f_8$ and $Δ_3/Δ_8$. Introducing the SU(3)-breaking effect suggested by the mass difference between the strange and nonstrange

Q. Y. Liu, M. Maris, S. T. Petcov

This is the first of two articles aimed at providing comprehensive predictions for the day-night (D-N) effect for the Super-Kamiokande detector in the case of the MSW $ν_e \to \numt$ transition solution of the solar neutrino problem. The one-year averaged probability of survival of the solar $\nue$ crossing the Earth mantle, the core, the inner 2/3 of the co

Stephen C. Davis, Anne-Christine Davis, Mark Trodden

We investigate the microphysics of supersymmetric cosmic strings. In particular we focus on the vortices admitted by N=1 supersymmetric abelian Higgs models. We find the vortex solutions and demonstrate that the two simplest supersymmetric cosmic string models admit fermionic superconductivity. Further, by using supersymmetry transformations, we show how to

Cai-Dian Lu, Da-Xin Zhang

We re-analyse the long distance contributions to the process $b \to s l^+ l^-$. Full $q^2$-behavior of the vector meson dominance amplitude is used together with the effect of Terasaki suppression, and comparisons with the previous results are given. We show that the interference between short- and long- distance contributions makes it difficult to extract t

R. Casalbuoni, S. De Curtis, D. Dominici

In this paper we consider a general $SU(2)_L\otimes SU(2)_R$ invariant Lagrangian describing scalar, vector and axial-vector resonances. By expanding the WW and the ZZ scattering amplitude up to the fourth order in the external momenta we can compare the parameters of our Lagrangian with the ones used in the effective chiral Lagrangian formalism. In the last

A. V. Belitsky

It is shown that twist-3 fragmentation functions in the large-$N_c$ limit of QCD obey the DGLAP evolution equations. The anomalous dimensions are found explicitly. The Gribov-Lipatov reciprocity is violated at the twist-3 level in the leading logarithmic approximation.

J. M. M. Senovilla, C. F. Sopuerta, P. Szekeres

In this paper we provide fully covariant proofs of some theorems on shear-free perfect fluids. In particular, we explicitly show that any shear-free perfect fluid with the acceleration proportional to the vorticity vector (including the simpler case of vanishing acceleration) must be either non-expanding or non-rotating. We also show that these results are n

Frank Gronwald

We give a self-contained introduction into the metric-affine gauge theory of gravity. Starting from the equivalence of reference frames, the prototype of a gauge theory is presented and illustrated by the example of Yang-Mills theory. Along the same lines we perform a gauging of the affine group and establish the geometry of metric-affine gravity. The result

Rong-Gen Cai, Zhi-Jiang Lu, Yuan-Zhong Zhang

The critical behavior and phase transition in the 2+1 dimensional Bañados, Teitelboim, and Zanelli (BTZ) black holes are discussed. By calculating the equilibrium thermodynamic fluctuations in the microcanonical ensemble, canonical ensemble, and grand canonical ensemble, respectively, we find that the extremal spinning BTZ black hole is a critical point, som

Erik Christensen

Let F be a linear unital map of a unital matrix algebra A over the complex numbers into the complex n by n matrices. Then F induces a linear unital map Fk of the k by k matrices over A into the complex nk by nk matrices by the action of F on each entry in the k by k matrices. If Fk preserves invertibility and k is greater than dim(alg(F(A)))-dim(F(A))+2 then

Igor F. Herbut

It is argued that the penetration depth and the correlation length at the critical point of the 3D superconductor diverge with the same critical exponents, as follows from the general scaling arguments and from the independent calculations in both Ginzburg-Landau and its dual theory. The incorrect prediction of Kiometzis, Kleinert and Schakel (KKS) that this

J. M. Kosterlitz, M. V. Simkin

An XY model with random phase shifts as a model for a superconducting glass is studied in two and three dimensions by a zero temperature domain wall renormalization group which allows one to follow the flows of both the coupling constant and the disorder strength with increasing length scale. Weak disorder is found to be marginal in two and probably irreleva

G. Haran, J. Taylor, A. D. S. Nagi

The specific heat jump at a normal-superconducting phase transition in an anisotropic superconductor with nonmagnetic impurities is calculated within a weak-coupling mean field approximation. It is shown that its dependence on the impurity concentration is remarkably different for d-wave and (d+s)-wave states. This effect may be used as a test for the presen

Yehoshua Levinson

We consider the dephasing of an one-electron state in a quantum dot due to charge fluctuations in a biased quantum point contact coupled to the dot capacitively. The contribution to the dephasing rate due to the bias depends on temperature and bias in the same way as shot-noise in the point contact at zero frequency, but do not follow the |t|^2(1-|t|^2) supp

Serge Galam

A modified version of a finite random field Ising ferromagnetic model in an external magnetic field at zero temperature is presented to describe group decision making. Fields may have a non-zero average. A postulate of minimum inter-individual conflicts is assumed. Interactions then produce a group polarization along one very choice which is however randomly

Karen Hallberg, Reinhold Egger

The behavior of two magnetic impurities coupled to correlated electrons in one dimension is studied using the DMRG technique for several fillings. On-site Coulomb interactions among the electrons lead to a small Kondo screening cloud and an overall suppression of magnetic order. For arbitrary electronic correlations and large inter-impurity distances R, we f

Hagen Kleinert, Adriaan M. J. Schakel

A recent paper by Herbut in J. Phys. A: Math. Gen. {\bf 29}, 1 (1996) is shown to contain an internal inconsistency which invalidates the principal conclusion of the paper that the magnetic penetration depth diverges with an XY-exponent rather than a mean-field exponent, as predicted some time ago by Kiometzis, Kleinert, and Schakel (KKS).

Masatoshi Imada, Youichirou Iino

We study effects of interladder coupling on critical magnetic properties of spin ladder systems doped with small concentrations of nonmagnetic impurities, using the scaling theory together with quantum Monte Carlo (QMC) calculations. Scaling properties in a wide region in the parameter space of the impurity concentration x and the interladder coupling are go

Hikaru Kawamura, Mai Suan Li

Possible occurrence of an equilibrium thermodynamic phase with a spontaneously broken time-reversal symmetry is studied in a model ceramic superconductor with anisotropic pairing symmetry. It is shown by Monte Carlo simulations that such a ``chiral-glass&#39;&#39; phase is truly stable even under the influence of screening. Existence of frustration in zero e

Uri Alon, David Mukamel

A model for the motion of ring-shaped DNA in a gel is introduced and studied by numerical simulations and a mean-field approximation. The ring motion is mediated by finger-shaped loops (hernias) that move in an amoeba-like fashion around the gel obstructions. This constitutes an extension of previous reptation tube treatments. It is shown that tension is ess

A. J. Fendrik, D. A. Wisniacki

To study the time decay laws (tdl) of quasibounded hamiltonian systems we have considered two finite potential wells with oscillating walls filled by non interacting particles. We show that the tdl can be qualitatively different for different movement of the oscillating wall at classical level according to the characteristic of trapped periodic orbits. Howev

Gulio Casati, B. V. Chirikov, O. V. Zhirov

The main purpose of this Comment is to point out that besides the short time scale of quantum chaos, confirmed once more in recent paper by Alicki et al, there is generally another time scale t_R, which is much longer and on which a partial quantum-classical correspondence persists. Namely, the quantum diffusion closely follows the classical one even though

Greg Bothun, Chris Impey, Stacy McGaugh

In twenty years, low surface brightness (LSB) galaxies have evolved from being an idiosyncratic notion to being one of the major baryonic repositories in the Universe. The story of their discovery and the characterization of their properties is told here. Their recovery from the noise of the night sky background is a strong testament to the severity of surfa

A. D. Kaminker, D. G. Yakovlev, P. Haensel

We study the emission of neutrinos, resulting from the scattering of electrons off magnetic flux tubes (fluxoids) in the neutron star cores with superfluid (superconducting) protons. In the absence of proton superfluidity (T> T_{cp}), this process transforms into the well known electron synchrotron emission of neutrino pairs in a locally uniform magnetic fie

S. Borgani, A. Gardini, M. Girardi, S. Gottloeber

We compare the distribution of internal velocity dispersions of galaxy clusters for an observational sample to those obtained from a set of N-body simulations of seven COBE-normalised cosmological scenarios: the standard CDM (SCDM) and a tilted (n=0.85) CDM (TCDM) model, a CHDM model with 25% of massive neutrinos, two low-density LCDM models with Omega_0=0.3

A. R. King, J. Frank, U. Kolb, H. Ritter

We show that stable disk accretion should be very rare among low-mass X-ray binaries and cataclysmic variables whose evolution is driven by the nuclear expansion of the secondary star on the first giant branch. Stable accretion is confined to neutron-star systems where the secondary is still relatively massive, and some supersoft white dwarf accretors. All o

Emilio E. Falco, Irwin I. Shapiro, Leonidas A. Moustakas, Marc Davis

We present long-slit LRIS/Keck spectroscopic observations of the gravitational lens system 0957+561. Averaged over all of our data, the rest-frame velocity dispersion sigma_v of the central lens galaxy G1 is sigma_v = 279 +- 12 km/s. However, there appears to be a significant decrease in sigma_v as a function of distance from the center of G1 that is not typ

R. P. van der Marel, S. Sigurdsson, L. Hernquist

We study the stability of stellar dynamical equilibrium models for M32. Kinematic observations show that M32 has a central black hole of 3x10^6 solar masses, and a phase-space distribution function that is close to the `two-integral&#39; form f=f(E,L_z). M32 is also rapidly rotating; 85-90% of the stars have the same sense of rotation around the symmetry axi

J. F. Bell

Young radio pulsars shed vast amounts of rotational energy, sometimes as high as 100,000 times the total energy loss rate from the sun. The wide range of phenomena resulting from this energy loss include: glitches, timing noise, jets, bow shocks, bullets and plerions and are be reviewed from an observational perspective. Past and proposed surveys for young r

Mu-In Park, Young-Jai Park

We present the newly improved Batalin-Fradkin-Tyutin (BFT) Hamiltonian formalism and the generalization to the Lagrangian formulation, which provide the much more simple and transparent insight to the usual BFT method, with application to the non-Abelian Proca model which has been an difficult problem in the usual BFT method. The infinite terms of the effect

Martin Siegert, Michael Plischke, Royce K. P. Zia

We discuss static and dynamic fluctuations of domain walls separating areas of constant but different slopes in steady-state configurations of crystalline surfaces both by an analytic treatment of the appropriate Langevin equation and by numerical simulations. In contrast to other situations that describe the dynamics in Ising-like systems such as models A a

Mina Aganagic, Jaemo Park, Costin Popescu, John H. Schwarz

Dual super Dp-brane actions are constructed by carrying out a duality transformation of the world-volume U(1) gauge field. The resulting world-volume actions, which contain a (p - 2)-form gauge field, are shown to have the expected properties. Specifically, the D1-brane and D3-brane transform in ways that can be understood on the basis of the SL(2, Z) dualit

T. Shanks

We make a direct test of Tully-Fisher distance estimates to eleven spiral galaxies with HST Cepheid distances and to twelve spiral galaxies with SNIa distances. The HST Cepheid distances come from the work of Freedman (1997), Sandage et al (1996) and Tanvir et al (1995). The SNIa distances come from Pierce (1994), calibrated using the Cepheid results of Sand

Pier S. Marrocchesi, Nello Paver

From a time-dependent analysis of the decay $B^0_{d} \to π^+ π^-$ and using a model-dependent $A_P/A_T$ ratio of the penguin-to-tree amplitudes contributing to the decay, both the weak phase $α$ and the strong phase shift difference $δ$ can be extracted from the data. The value of the weak phase $β$, expected to be measured from the decay $B^0_{d} \to J/ψK_S

A. V. Belitsky, D. Muller

We evaluate the complete leading-order evolution kernels for the chiral-odd twist-3 distributions $e(x)$ and $\widetilde h_L(x)$ of the nucleon. We establish the connection between the evolution equations in light-cone position and light-cone fraction representations, which makes a correspondence between the non-local string operator product expansion and th

Lando Caiani, Lapo Casetti, Cecilia Clementi, Marco Pettini

The Hamiltonian dynamics of classical planar Heisenberg model is numerically investigated in two and three dimensions. By considering the dynamics as a geodesic flow on a suitable Riemannian manifold, it is possible to analytically estimate the largest Lyapunov exponent in terms of some curvature fluctuations. The agreement between numerical and analytical v

R. B. Palmer, J. C. Gallardo

We consider the high energy advantages, disadvantages and luminosity requirements of hadrons, leptons and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed.

Rita Seungjung Kim, Michael A. Strauss

To probe the weakly non-linear regime, past the point where simple linear theory is sufficient to describe the statistics of the density distribution, we measure the skewness (S_3) and kurtosis (S_4) of the Count Probability Distribution Function (CPDF) of the IRAS 1.2 Jy sample obtained from counts in cells. These quantities are free parameters in a maximum

Orfeu Bertolami

It is argued that, in models where the gravitational coupling is scale-dependent, predictions concerning weak gravitational lensing and shear are essentially similar to the ones derived from General Relativity. This is consistent with recent negative results of observations of the MS1224, CL2218 and A1689 systems aimimg to infer from those methods the presen

Ivan Cherednik

In the paper we formulate and verify a difference counterpart of the Macdonald-Mehta conjecture and its generalization for the Macdonald polynomials. Namely, we determine the Fourier transforms of the polynomials multiplied by the Gaussian, which is closely connected with the new difference Harish-Chandra theory.

W. J. Chaplin, Y. Elsworth, G. R. Isaak, C. P. McLeod

The fine-structure spacing $d_{\ell}(n) = ν_{\ell,n} - ν_{\ell+2,n-1}$ for low-degree solar p modes of angular degree $\ell$ and radial order n, is sensitive to conditions in the deep radiative interior of the Sun. Here, we present fine-structure spacings derived from the analysis of nearly five years of helioseismological data collected between 1991 July an

Thomas Buchert, Alvaro Dominguez

The generally held view that a model of large-scale structure, formed by collisionless matter in the Universe, can be based on the matter model ``dust&#39;&#39; fails in the presence of multi-stream flow, i.e., velocity dispersion. We argue that models for large-scale structure should rather be constructed for a flow which describes the average motion of a m

S. Ole Warnaar

Recently, Andrews and Berkovich introduced a trinomial version of Bailey&#39;s lemma. In this note we show that each ordinary Bailey pair gives rise to a trinomial Bailey pair. This largely widens the applicability of the trinomial Bailey lemma and proves some of the identities proposed by Andrews and Berkovich.

Junsoo Shin

We construct parity and time reversal invariant Maxwell-Chern-Simons gauge theory coupled to fermions with adding the parity partner to the matter and the gauge fields, which can give nontopological vortex solutions depending on the sign of the Chern-Simons coupling constant.

Yuri B. Suris

We find time discretizations for the two &#39;&#39;second flows&#39;&#39; of the Ablowitz-Ladik hierachy. These discretizations are described by local equations of motion, as opposed to the previously known ones, due to Taha and Ablowitz. Certain superpositions of our maps allow a one-field reduction and serve therefore as valid space-time discretizations of

R. B. Palmer, J. C. Gallardo

Parameters are given of 4 TeV and 0.5 TeV (c-of-m) high luminosity muon-muon Colliders. We discuss the various systems, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleartion and storage in a collider ring. Detector background, polarization are analyzed. We also look at other type of colliders (had

Federico Finkel, Artemio González-López, Miguel A. Rodríguez

In this paper, we study Lie superalgebras of $2\times 2$ matrix-valued first-order differential operators on the complex line. We first completely classify all such superalgebras of finite dimension. Among the finite-dimensional superalgebras whose odd subspace is nontrivial, we find those admitting a finite-dimensional invariant module of smooth vector-valu

Chaz Schlindwein

We prove that any countable support iteration formed with posets with $ω_2$-p.i.c.\ has $ω_2$-c.c., assuming CH in the ground model and assuming also that $ω_1$ is not collapsed. This improves earlier results of Shelah by removing the restriction on the length of the iteration. Thus, we solve the problem of obtaining a large continuum via such forcing iterat

Adrian R. Lugo

We compute the exact effective string vacuum backgrounds of the level $k = 81/19 SU(2,1)/U(1)$ coset model. A compact SU(2) isometry present in this seven dimensional solution allows to interpreting it after compactification as a four dimensional non-abelian SU(2) charged instanton with a singular submanifold and an $SO(3) \times U(1)$ isometry. The semiclas

A. Feoli, G. Lambiase, G. Papini, G. Scarpetta

We calculate the first order maximal acceleration corrections to the classical electrodynamics of a particle in external electromagnetic fields. These include additional dissipation terms, the presence of a critical electric field, a correction to the cyclotron frequency of an electron in a constant magnetic field and the power radiated by the particle. The

G. Lambiase, G. Papini, G. Scarpetta

The maximal acceleration corrections to the Lamb shift of one--electron atoms are calculated starting from the Dirac equation and splitting the spinor into large and small components. The results depend on $Z^8$ and a cut-off $Λ$. Sizeable values are obtained even at Z=1 for $Λ\sim a_0/2$, where $a_0$ is the Bohr radius. These values are compatible with theo

Jouko Mickelsson

A nonperturbative approach to the vacuum polarization for quantized fermions in external vector potentials is discussed. It is shown that by a suitable choice of counterterms the vacuum polarization phase is both gauge and renormalization independent, within a large class of nonperturbative renormalizations.

M. Ishi-i, T. Kashiwa, N. Tanimura

A detailed analysis is performed for the Nambu--Jona-Lasinio model coupled with constant (external) magnetic and/or electric fields in two, three, and four dimensions. The infrared cut-off is essential for a well-defined functional determinant by means of the proper time method. Contrary to the previous observation, the critical coupling remains nonzero even

Stefano De Leo

We find in our quaternionic version of the electroweak theory an apparently hopeless problem: In going from complex to quaternions, the calculation of the real-valued parameters of the CKM matrix drastically changes. We aim to explain this quaternionic puzzle.

Masahiro Anazawa

We investigate the correlators in unitary minimal conformal models coupled to two-dimensional gravity from the two-matrix model. We show that simple fusion rules for all of the scaling operators exist. We demonstrate the role played by the boundary operators and discuss its connection to how loops touch each other.

Christof Wetterich

The time-dependence of correlation functions under the influence of classical equations of motion is described by an exact evolution equation. For conservative systems thermodynamic equilibrium is a fixed point of these equations. We show that this fixed point is not universally stable, since infinitely many conserved correlation functions obstruct the appro

Sin Kyu Kang, Gye T. Park

We study the question of distinguishability of the Higgs sector between the standard model with four generations(SM4) and the minimal supersymmetric standard model with four generations (MSSM4). We find that a gap exists between the SM4 and MSSM4 Higgs boson masses for a range of the fourth generation fermion mass considered in the analysis at a fixed top qu

J. Soffer, O. V. Teryaev

We derive the analog of the Wandzura-Wilczek relation for the light-cone distributions of polarized gluons in a transversely polarized nucleon. The short distance cross-section is entirely due to the intrinsic transverse momenta of gluon in the nucleon, in complete analogy to the quark case. Numerical estimate for the double spin transverse asymmetries at RH

M. Oka, D. Jido, A. Hosaka

Masses and couplings of the negative parity excited baryons are studied in the QCD sum rule. Separation of the negative-parity spectrum is proposed and is applied to the flavor octet and singlet baryons. We find that the quark condensate is responsible for the mass splitting of the ground and the negative-parity excited states. This is expected from the chir

Lee Smolin

The roles that spin networks play in gauge theories, quantum gravity and topological quantum field theory are briefly described, with an emphasis on the question of the relationships among them. It is argued that spin networks and their generalizations provide a language which may lead to a unification of the different approaches to quantum gravity and quant

Kenneth J. Dykema, Mikael Rordam

Consider the reduced free product of C*-algebras, (A,ϕ)=(A_1,ϕ_1)*(A_2,ϕ_2), with respect to states ϕ_1 and ϕ_2 that are faithful. If ϕ_1 and ϕ_2 are traces, if the so-called Avitzour conditions are satisfied, (i.e. A_1 and A_2 are not ``too small&#39;&#39; in a specific sense) and if A_1 and A_2 are nuclear, then it is shown that the positive cone of the K_

Kenneth J. Dykema

A necessary and sufficient condition for the simplicity of the C*-algebra reduced free product of finite dimensional abelian algebras is found, and it is proved that the stable rank of every such free product is 1. Related results about other reduced free products of C*-algebras are proved.

Kenneth J. Dykema

It is proved that the free product state, in the reduced free product of C*-algebras, is faithful if the initial states are faithful.

V. M. Manuilov

For a wide class of pairs of unbounded selfadjoint operators with bounded commutator we construct a K-theoretical integer invariant which is continuous, is equal to zero for commuting operators and is equal to one for the pair (x, i d/dx).

P. G. Grinevich, M. U. Schmidt

We show, that higher analogs of the Willmore functional, defined on the space of immersions M^2\rightarrow R^3, where M^2 is a two-dimensional torus, R^3 is the 3-dimensional Euclidean space are invariant under conformal transformations of R^3. This hypothesis was formulated recently by I.A.Taimanov (dg-ga/9610013). Higher analogs of the Willmore functional

V. F. Kirichenko, O. E Arseneva

Notions of self-dual and anti self-dual almost quaternionic structures are introduced. The complete classification of self-dual and anti self-dual generalized Kaehler manifolds is obtained.

V. F. Kirichenko, O. E Arseneva

The fibre bundles adjoint to generalized almost quaternionic structures are studied. The most important classes of generalized almost quaternionic manifolds are considered.

Diptiman Sen, R. K. Bhaduri

We use the collective field theory known for the Calogero-Sutherland model to study a variety of low-energy properties. These include the ground state energy in a confining potential upto the two leading orders in the particle number, the dispersion relation of sound modes with a comparison to the two leading terms in the low temperature specific heat, large

Andreas Knaebchen, Ora Entin-Wohlman, Yuri Galperin, Yehoshua Levinson

The absorption of surface acoustic waves (SAW&#39;s) by an array of quantum dots in which the mean level spacing Delta is larger than the sound frequency omega, the temperature T, and the phase breaking rate tau^{-1}_phi is considered. The direct and the intra-level (Debye) contributions to the SAW attenuation coefficient Gamma are evaluated, and it is shown

Andreas Knaebchen

The transport relaxation rate 1/tau of a two-dimensional electron gas due to scattering by thermally excited surface acoustic phonons is calculated. The temperature dependence of 1/tau is found to be linear in T for high temperatures, but decreases like T^alpha as T drops below the Bloch-Gruneisen temperature for surface sound; alpha=7 (5) for the deformatio

F. C. Alcaraz, J. C. Xavier

The partition function of the Baxter-Wu model is exactly related to the generating function of a site-colouring problem on a hexagonal lattice. We extend the original Bethe ansatz solution of these models in order to obtain the eigenspectra of their transfer matrices in finite geometries and general toroidal boundary conditions. The operator content of these

D. F. Agterberg, T. M. Rice, M. Sigrist

We show that for superconducting Sr_2RuO_4 any unconventional pairing in the part of the Fermi surface with Ru 4d-xy orbital character is weakly coupled to that with Ru 4d-xz, 4d-yz orbital character. This naturally gives rise to two disparate energy scales in the superconducting state which leads to novel low temperature properties in a variety of thermodyn

V. Celebonovic

Using the Hubbard model on a 1D lattice and the &#34;memory function&#34; approach,we have calculated the electrical conductivity of a 1D system of correlated electrons on a lattice. We have determined the temperature and frequency profiles of the conductivity. Effects of changes of the band filling on the conductivity were also briefly discussed.The results

Karen Sparck Jones

Information technology should have much to offer linguistics, not only through the opportunities offered by large-scale data analysis and the stimulus to develop formal computational models, but through the chance to use language in systems for automatic natural language processing. The paper discusses these possibilities in detail, and then examines the act

Atsushi Fujii, Kentaro Inui, Takenobu Tokunaga, Hozumi Tanaka

This paper proposes an efficient example selection method for example-based word sense disambiguation systems. To construct a practical size database, a considerable overhead for manual sense disambiguation is required. Our method is characterized by the reliance on the notion of the training utility: the degree to which each example is informative for futur

Richard Mushotzky, Michael Loewenstein

We present the first large sample of accurate iron abundances and temperatures for clusters at redshifts greater than 0.14. We find that the Fe abundance shows little or no evolution out to redshift 0.3. This and the early formation epoch of elliptical galaxies in clusters indicate that most of the enrichment of the intracluster medium occurred at redshifts