March 1995 arXiv papers

Doochul Kim

A perturbative method is developed to calculate the finite size corrections of the low lying energies of the asymmetric XXZ hamiltonian near the stochastic line. The crossover from isotropic to anisotropic, Kardar-Parisi-Zhang (KPZ) scaling of the mass gaps is determined in terms of universal crossover scaling functions. At the stochastic line, the asymmetri

Troy A. Schilling

A key aspect of a recent proposal for a {\em generalized loop representation} of quantum Yang-Mills theory and gravity is considered. Such a representation of the quantum theory has been expected to arise via consideration of a particular algebra of observables -- given by the traces of the holonomies of {\em generalized loops}. We notice, however, a technic

Orlando Alvarez, Chien-Hao Liu

It has been suggested that a possible classical remnant of the phenomenon of target-space duality (T-duality) would be the equivalence of the classical string Hamiltonian systems. Given a simple compact Lie group $G$ with a bi-invariant metric and a generating function $Γ$ suggested in the physics literature, we follow the above line of thought and work out

J. S. Bagla, T. Padmanabhan

In an expanding universe, velocity field and gravitational force field are proportional to each other in the linear regime. Neither of these quantities evolve in time and these can be scaled suitably so that the constant of proportionality is unity and velocity and force field are equal. The Zeldovich approximation extends this feature beyond the linear regi

Tim R. Morris

For all Poincaré invariant Lagrangians of the form ${\cal L}\equiv f(F_{μν})$, in three Euclidean dimensions, where $f$ is any invariant function of a non-compact $U(1)$ field strength $F_{μν}$, we find that the only continuum limit (described by just such a gauge field) is that of free field theory: First we approximate a gauge invariant version of Wilson&#

V. D. Ivashchuk, V. N. Melnikov

A cosmological model describing the evolution of n Ricci-flat spaces (n>1) in the presence of 1-component perfect-fluid and minimally coupled scalar field is considered. When the pressures in all spaces are proportional to the density, the Einstein and Wheeler-DeWitt equations are integrated for a large variety of parameters. Classical and quantum wormhole s

D. Arnaudon, C. Chryssomalakos, L. Frappat

We examine the two parameter deformed superalgebra $U_{qs}(sl(1|2))$ and use the results in the construction of quantum chain Hamiltonians. This study is done both in the framework of the Serre presentation and in the $R$-matrix scheme of Faddeev, Reshetikhin and Takhtajan (FRT). We show that there exists an infinite number of Casimir operators, indexed by i

Z. K. Silagadze

The existence of the mirror world, with the same microphysics as our own one but with opposite P-asymmetry, not only restores an exact equivalence between left and right but also naturally explains, via a see-saw like mechanism, why the neutrino is ultralight.

P. Forgács, P. A. Horváthy, Z. Horváth, L. Palla

Some of the motivations for as well as the main points of the quantization of the Nappi Witten string in the light cone gauge are reviewed.

Michel Dubois-Violette, Peter W. Michor

We define and study the theory of derivation-based connections on a recently introduced class of bimodules over an algebra which reduces to the category of modules whenever the algebra is commutative. This theory contains, in particular, a noncommutative generalization of linear connections. We also discuss the different noncommutative versions of differenti

Joachim Ankerhold, Hermann Grabert, Gert-Ludwig Ingold

We study the real time dynamics of a quantum system with potential barrier coupled to a heat-bath environment. Employing the path integral approach an evolution equation for the time dependent density matrix is derived. The time evolution is evaluated explicitly near the barrier top in the temperature region where quantum effects become important. It is show

D. Kazhdan, Y. Soibelman

In this paper we define a quantum version of the ``fusion'' tensor product of two representations of an affine Kac-Moody algebra.It is replaced by what we call fusion action of the category of finite-dimensional representations of quantum affine algebra on its highest weight representations. We construct a quantum version of the associativity constra

A. A. Balinsky, Yu. M. Burman

The paper is devoted to the Poisson brackets compatible with multiplication in associative algebras. These brackets are shown to be quadratic and their relations with the classical Yang--Baxter equation are revealed. The paper also contains a description of Poisson Lie structures on Lie groups whose Lie algebras are adjacent to an associative structure.

D. Troltenier, C. Bahri, J. P. Draayer

An extended version of the pseudo-SU(3) model which includes both spin and proton-neutron degrees of freedom is used to study the influence of the pairing interaction on K-band mixing, B(E2) values and quadrupole moments. Using the asymmetric rotor model as a backdrop, specific consequences of a many-particle shell-model based description of these collective

Alejandro Adem

In this paper we use families of finite subgroups to study Grothendieck rings associated to certain discrete groups, such as the arithmetic ones.

Aviezri S. Fraenkel

Aim: Present a systematic development of part of the theory of combinatorial games from the ground up. Approach: Computational complexity. Combinatorial games are completely determined; the questions of interest are efficiencies of strategies. Methodology: Divide and conquer. Ascend from Nim to chess in small strides at a gradient that's not too steep. P

A. LeClair, G. Mussardo, H. Saleur, S. Skorik

We study the ground state energy of integrable $1+1$ quantum field theories with boundaries (the genuine Casimir effect). In the scalar case, this is done by introducing a new, ``R-channel TBA'', where the boundary is represented by a boundary state, and the thermodynamics involves evaluating scalar products of boundary states with all the states of the theo

B. M. Pimentel, J. L. Tomazelli

In this letter we argue that there is no ambiguity between the Pauli-Villars and other methods of regularization in (2+1)-dimensional quantum electrodynamics with respect to dynamical mass generation, provided we properly choose the couplings for the regulators.

Jisuke Kubo, 11 pages, KANAZAWA-94-01

An evidence for nontriviality of asymptotically non-free (ANF) Yang-Mills theories is found on the basis of optimized perturbation theory. It is argued that these theories with matter couplings can be made nontrivial by means of the reduction of couplings, leading to the idea of dynamical unification of couplings (DUC) The second-order reduction of couplings

Afsar Abbas

It is shown, for the first time , that surprisingly the electric charge loses all physical meaning above the electro-weak phase transition temperature. Implications of this discovery in the context of the early universe within the framework of various unified models are discussed.

L. Roszkowski

I review some aspects of supersymmetric grand unification and emphasize a recent development in the area of gauge coupling unification.

Daryl Scora, Nathan Isgur

We present the predictions of ISGW2, an update of the ISGW quark model for semileptonic meson decays. The updated model incorporates a number of features which should make it more reliable, including the constraints imposed by Heavy Quark Symmetry, hyperfine distortions of wavefunctions, and form factors with more realistic high recoil behaviors.

Adam F. Falk

Theoretical aspects of rare $B$ decays are reviewed. The focus is on the relation between short-distance interactions and physical observables. It is argued that there remain significant uncertainties in the theoretical treatment of certain important quantities. (Talk presented at the International Symposium on Vector Boson Interactions, University of Califo

B. W. Harris, J. Smith

We have completed the next-to-leading order perturbative QCD corrections to the virtual-photon exclusive differential cross sections for heavy quark production in deep-inelastic electron-proton scattering, i.e. $e + P \rightarrow Q + \overline{Q} + X$. Using these results, we have computed distributions which are sensitive to correlations among the heavy qua

J. Sirkka, I. Vilja

We study the subcritical bubble formation near the phase space domain wall. We take into account that the phase of the scalar field can vary using complex U(1) symmetric field and a phenomenological potential with cubic term responsible to symmetry breaking. We show that the presence of the domain wall induces subcritical bubbles so that their formation rate

Masato JIMBO, Tadashi KON, Hidekazu TANAKA, Toshiaki KANEKO

We introduce a new method to treat Majorana fermions on the GRACE system, which has already been developed for the computation of the matrix elements for the processes of the standard model. In the standard model, we already have included such particles as Dirac fermions, gauge bosons and scalar bosons in the system. On the other hand, there are four Majoran

Graciela Gelmini, Bruce Ritzi

Here we point out that the four-nucleon terms incorporate into lowest order non-linear chiral effective Lagrangians the same description of bulk nuclear matter contained in the Walecka model, that is generally considered satisfactory. We find this point worth noticing because, while the Walecka model is an entirely phenomenological renormalizable model, non-

H. Baer, A. Bartl, C. H. Chen, H. Eberl

We summarize the current status and future prospects for low energy (weak scale) supersymmetry. In particular, we evaluate the capabilities of various $e^+e^-$, $p\bar p$ and $pp$ colliders to discover evidence for supersymmetric particles. Furthermore, assuming supersymmetry is discovered, we discuss capabilities of future facilities to dis-entangle the ant

K. Rummukainen, Steven Gottlieb

Many low energy hadrons, such as the rho, can be observed as resonances in scattering experiments. A proposal by Lüscher enables one to determine infinite volume elastic scattering phases from the two-particle energy spectrum measured from finite periodic lattices. In this work, we generalize the formalism to the case where the total momentum of the particle

Enzo Marinari, Maria Luigia Paciello, Bruno Taglienti

A review article on string tension concept and their relevance as non-perturbative quantity on the study of quark confinement in lattice gauge theories. A detailed description of a variety of methods to measure the string tension on the lattice and an indication of the most promising developments is proposed.

CJ Isham, N Linden

We treat continuous histories within the histories approach to generalised quantum mechanics. The essential tool is the `history group': the analogue, within the generalised history scheme, of the canonical group of single-time quantum mechanics.

N. J. Hitchin, N. S. Manton, M. K. Murray

We discuss $SU(2)$ Bogomolny monopoles of arbitrary charge $k$ invariant under various symmetry groups. The analysis is largely in terms of the spectral curves, the rational maps, and the Nahm equations associated with monopoles. We consider monopoles invariant under inversion in a plane, monopoles with cyclic symmetry, and monopoles having the symmetry of a

Alon Drory

This paper presents a general approach to linear stochastic processes driven by various random noises. Mathematically, such processes are described by linear stochastic differential equations of arbitrary order (the simplest non-trivial example is $\ddot x = R(t)$, where $R(t)$ is not a Gaussian white noise). The stochastic process is discretized into $n$ ti

J. Machta, R. Greenlaw

In this paper we examine a number of models that generate random fractals. The models are studied using the tools of computational complexity theory from the perspective of parallel computation. Diffusion limited aggregation and several widely used algorithms for equilibrating the Ising model are shown to be highly sequential; it is unlikely they can be simu

A. J. Bray, C. L. Emmott

The coarsening dynamics of the Cahn-Hilliard equation with order-parameter dependent mobility, $λ(ϕ) \propto (1-ϕ^2)^α$, is addressed at zero temperature in the Lifshitz-Slyozov limit where the minority phase occupies a vanishingly small volume fraction. Despite the absence of bulk diffusion for $α>0$, the mean domain size is found to grow as $<R > \propto t

S. Franz, G. Parisi

In this paper we develop a method introduced by one of us to study metastable states in spin glasses. We consider a `potential function&#39; defined as the free energy of a system at a given temperature $T$ constrained to have a fixed overlap with a reference configuration of equilibrium at temperature $T&#39;$. We apply the method to the spherical p-spin gl

R. Monasson

The metastable states of a glass are counted by adding a weak pinning field which explicitly breaks the ergodicity. Their entropy, that is the logarithm of their number, is extensive in a range of temperatures $T_G < T < T_C$ only, where $T_G$ and $T_C$ correspond to the ideal calorimetric and kinetic glass transition temperatures respectively. An explicit s

Alexei Iantchenko, Elliott H. Lieb, Heinz Siedentop

The strong Scott conjecture about the electron density at a distance 1/Z from an atomic nucleus of charge $Z$ and its generalization for molecules are proved. The density, suitably scaled, converges to an explicit limiting density as $Z \to \infty$. Both a weak convergence and a pointwise convergence on spheres holds.

X de Hemptinne

The dynamics of irreversible relaxation of non-equilibrium macroscopic systems is discussed. Arguments are developed showing that the general process is supported by two independent successive mechanisms. One is mixing and it follows pure conservative dynamics. It does not lead to thermodynamic equilibrium. The second step involves dissipation to the outside

Silvia Zane, Roberto Turolla, Luca Zampieri, Monica Colpi

The issue of the observability of Old Isolated Neutron Stars (ONSs) accreting from the interstellar gas, is reconsidered using the spectra presented in Zampieri {\it et al.\/} (1995). In particular, we focus our attention on the overall soft X--ray emission of ONSs, which may provide a substantial contribution to the X--ray background in the 0.5--2 keV band.

Todd R. Hunter, Leonardo Testi, Greg B. Taylor, Marcello Felli

We present molecular line, H2O maser, radio continuum and near infrared maps of the bipolar outflow source AFGL5142. The high resolution of our molecular CO observations enables us to define the morphology of the large-scale bipolar outflow into a two lobe structure extending for 2&#39; on each side of the center. In the perpendicular direction, we find cons

R. B. Palmer, J. C. Gallardo, R. C. Fernow, Y. Torun

Muon production requirements for a muon collider are presented. Production of muons from pion decay is studied. Lithium lenses and solenoids are considered for focussing pions from a target, and for matching the pions into a decay channel. Pion decay channels of alternating quadrupoles and long solenoids are compared. Monte Carlo simulations are presented fo

Richard C. Fernow, Juan C. Gallardo

Transverse ionization cooling of muons is modeled as a Brownian motion of the muon beam as it traverses a Li or Be rod. A Langevin like equation is written for the free particle case (no external transverse magnetic field) and for the case of a harmonically bound beam in the presence of a focusing magnetic field. We demonstrate that the well known muon cooli

R. B. Palmer, J. C. Gallardo, R. C. Fernow, H. Kirk

We discuss the various beam dynamics problems in muon collider systems, starting from the proton accelerator needed to generate the muon beams and proceeding through the muon storage ring.

Kyungsik Kang, Sin Kyu Kang

We critically reexamine the precision tests of the standard model by coupling the current world average value of $M_W$ with the recent LEP electroweak data with the aid of a modified ZFITTER program to include the dominant two-loop and QCD-EW mixed terms. The results show a clear evidence of nonvanishing electroweak radiative corrections. The recent CDF $m_t

Gary T. Horowitz, Robert Myers

We point out that spacetime singularities play a useful role in gravitational theories by eliminating unphysical solutions. In particular, we argue that any modification of general relativity which is completely nonsingular cannot have a stable ground state. This argument applies both to classical extensions of general relativity, and to candidate quantum th

Boris Chibisov Ariel R. Zhitnitsky

We discuss some QCD constraints on light-cone $π$ meson wave function $ψ(\k, x)$ . The analysis is based on such general methods as dispersion relations, duality and PCAC. We calculate the asymptotical behavior of the wave function ($wf$) at the end-point region ($x\to 1$ and $\k\to\infty$) by analysing the corresponding large $n-$th moments in transverse $\

S. Suresh Rao, Somendra M. Bhattacharjee

We explicitly show the connection between the protein folding problem and spin glass transition. This is then used to identify appropriate quantities that are required to describe the transition. A possible way of observing the spin glass transition is proposed.

Markus Finkemeier, Erwin Mirkes

Predictions for semi-leptonic decay rates of the tau lepton into two and three meson final states with one or two kaons are derived, including a discussion of K_S pi- K_S, K_L pi- K_L and K_S pi- K_L. The hadronic matrix elements are expressed in terms of form factors, which can be predicted by chiral Lagrangians supplemented by informations about all possib

J. Marklof

Asymptotic laws for mean multiplicities of lengths of closed geodesics in arithmetic hyperbolic three-orbifolds are derived. The sharpest results are obtained for non-compact orbifolds associated with the Bianchi groups SL(2,o) and some congruence subgroups. Similar results hold for cocompact arithmetic quaternion groups, if a conjecture on the number of gap

Eva Silverstein, Edward Witten

It is argued that many linear (0,2) models flow in the infrared to conformally invariant solutions of string theory. The strategy in the argument is to show that the effective space-time superpotential must vanish because there is no place where it can have a pole. This conclusion comes from either of two different analyses, in which the Kahler class or the

E. Beggs, J. Gould, S. Majid

We compute the quantum double, braiding and other canonical Hopf algebra constructions for the bicrossproduct Hopf algebra $H$ associated to the factorization of a finite group into two subgroups. The representations of the quantum double are described by a notion of bicrossed bimodules, generalising the cross modules of Whitehead. We also show that self-dua

P. Crehan, T. G. Ho

Phase-space realisations of an infinite parameter family of quantum deformations of the boson algebra in which the $q$-- and the $qp$--deformed algebras arise as special cases are studied. Quantum and classical models for the corresponding deformed oscillators are provided. The deformation parameters are identified with coefficients of non-linear terms in th

E. V. Podivilov, D. A. Shapiro, M. G. Stepanov

The profile of a Bennett hole induced by laser field in ionic distribution in collisional plasma is calculated. Influence of Chandrasekhar&#39;s dependence of coefficients of velocity space transport on the profile is included into the calculation for the first time. It is found that the hole narrows down as the field detuning frequency increases. Physical c

Armen Edigarian

In the paper we generalize the notion of problem (P) introduced by Poletsky. We introduce the notion of (P_m) extremals. For example, geodesics are (P_1) extremals. Using obtained results we present a description of (P_m) extremals in arbitrary complex ellipsoids. It is a generalization of the result obtained by Jarnicki-Pflug-Zeinstra. We also have a proof

James V. Steele, Ajay Subramanian, Ismail Zahed

The general correlations between massless fermions are calculated in the Schwinger model at arbitrary temperature. The zero temperature calculations on the plane are reviewed and clarified. Then the finite temperature fermionic Green&#39;s function is computed and the results on the torus are compared to those on the plane. It is concluded that a simpler way

Stefan Lenz, Bernd Schreiber

The Poincare algebra of classical electrodynamics in one spatial dimension is studied using light-cone coordinates and ordinary Minkowski coordinates. We show that it is possible to quantize the theory by a canonical quantization procedure in a Poincare invariant manner on the light-cone. We also show that this is not possible when using ordinary coordinates

Metin Gurses, Emre Sermutlu

Collision of plane waves in dilaton gravity theories and low energy limit of string theory is considered. The formulation of the the problem and some exact solutions are presented.

Laszlo Feher, Ian Marshall

The $p\times p$ matrix version of the $r$-KdV hierarchy has been recently treated as the reduced system arising in a Drinfeld-Sokolov type Hamiltonian symmetry reduction applied to a Poisson submanifold in the dual of the Lie algebra $\widehat{gl}_{pr}\otimes {\Complex}[λ, λ^{-1}]$. Here a series of extensions of this matrix Gelfand-Dickey system is derived

M. Yu. Kalmykov, P. I. Pronin

The ambiguity in the calculations of one-loop counterterms by the background field method in nonrenormalizable theories of gravity is discussed. Some examples of such ambiguous calculations are given. The non-equivalence of the first and second order formalism in the quantum gravity is shown.

V. A. Soroka

Some applications of the odd Poisson bracket to the description of the classical and quantum dynamics are represented.

G. K. Savvidy, K. G. Savvidy, F. J. Wegner

We are able to perform the duality transformation of the spin system which was found before as a lattice realization of the string with linear action. In four and higher dimensions this spin system can be described in terms of a two-plaquette gauge Hamiltonian. The duality transformation is constructed in geometrical and algebraic language. The dual Hamilton

M. G. Olsson, S. Veseli, K. Williams

We present a systematic algebraic and numerical investigation of the instantaneous Bethe-Salpeter equation. Emphasis is placed on confining interaction kernels of the Lorentz scalar, time component vector, and full vector types. We explore stability of the solutions and Regge behavior for each of these interactions, and conclude that only time component vect

O. Benhar, S. Liuti

We discuss how the virtuality of the struck particle may affect the final state interactions in electron-nucleus scattering. The extent to which short range correlations inhibit rescattering taking place within the range of the repulsive core of the NN interaction is quantitatively analyzed. The possible modifications of the nucleon-nucleon scattering amplit

V. Anisovich, D. Melikhov, V. Nikonov

We consider the pion structure in the region of low and moderately high momentum transfers: at low $Q^2$, the pion is treated as a composite system of constituent quarks; at moderately high momentum transfers, $Q^2=10\div25\;GeV^2$, the pion \ff is calculated within perturbative QCD taking into account one--gluon hard exchange. Using the data on pion \ff at

J. L. Goity, Marc Sher

The most general supersymmetric model contains baryon number violating terms of the form $\lm_{ijk}\ \ov{D}_i\ \ov{D}_j\ \ov{U}_k$ in the superpotential. We reconsider the bounds on these couplings, assuming that lepton number conservation ensures proton stability. These operators can mediate $n-\ov{n}$ oscillations and double nucleon decay. We show that neu

M. Shmatikov

Width of molecular-type $Q\bar{Q}q\bar{q}$ hadronic states is discussed. It depends on the quantum numbers of the state and on the details of the long-range mechanism ensuring the bindedness of a molecule. Specific cases when the width is large are considered in detail.

A. A. Penin, A. A. Pivovarov

We consider a two-point correlator in massless $ϕ^3$ model within the ladder approximation . The spectral density of the correlator is known explicitly and does not contain any resonances. Meanwhile making use of the standard sum rules technique with a simple &#34;resonance + continuum&#34; model of the spectrum allows to predict parameters of the &#34;reson

Youngman Kim, Hyun Kyu Lee, Mannque Rho

We calculate the finite-temperature corrections in the dilated chiral quark model using the effective potential formalism. Assuming that the dilaton limit is applicable at some short length scale, we interpret the results to represent the behavior of hadrons in dense {\it and} hot matter. We obtain the scaling law, $\frac{f_π(T)}{f_π} = \frac{m_Q (T)}{m_Q} \

C. Hamzaoui, M. E. Pospelov

We show that the existence of a possible fourth heavy generation of quarks gives rise to a significant enhancement to the neutron electric dipole moment in comparison with the Standard Model prediction. The smaller degree of suppression in this case is linked to the presence of the operators of dimension $\leq$ 6 which enter into the effective Lagrangian wit

M. Goeckeler, R. Horsley, P. E. L. Rakow, G. Schierholz

We investigate effective Yukawa couplings of mesons to the elementary fermions in noncompact lattice QED. The couplings are extracted from suitable fermion-antifermion-meson three-point functions calculated by Monte Carlo simulations with dynamical staggered fermions. The scaling behaviour is compatible with expectations from perturbation theory, thus indica

Claes Uggla, Robert T. Jantzen, Kjell Rosquist

A framework is introduced which explains the existence and similarities of most exact solutions of the Einstein equations with a wide range of sources for the class of hypersurface-homogeneous spacetimes which admit a Hamiltonian formulation. This class includes the spatially homogeneous cosmological models and the astrophysically interesting static spherica

B. Linet

We consider a point charge fixed in the Rindler coordinates which describe a uniformly accelerated frame. We determine an integral expression of the induced charge density due to the vacuum polarization at the first order in the fine structure constant. In the case where the acceleration is weak, we give explicitly the induced electrostatic potential.

Sergey Merkulov, Henrik Pedersen

It is shown that moduli spaces of complete families of compact complex hypersurfaces in complex manifolds often come equipped canonically with projective structures satisfying some natural integrability conditions.

C. Quitmann, B. Beschoten, R. J. Kelley, G. Guentherodt

Substitution of rare-earth ions for Ca in Bi2Sr2CaCu2O8+y is known to cause a metal-insulator transition. Using resonant photoemission we study how this chemical substitution affects the electronic structure of the material. For the partial Cu-density of states at E_F and in the region of the valence band we observe no significant difference between a pure s

Clement Sire, Satya N. Majumdar

We study the nonequilibrium dynamics of the $q$-state Potts model following a quench from the high temperature disordered phase to zero temperature. The time dependent two-point correlation functions of the order parameter field satisfy dynamic scaling with a length scale $L(t)\sim t^{1/2}$. In particular, the autocorrelation function decays as $L(t)^{-λ(q)}

Sanjoy K. Sarker

The normal-state resistivity of the cuprate superconductors is metallic in the $ab$ plane but is characteristic of an insulator along the $c$ direction, leading to the possibility of the remarkable phenomenon of confinement. By continuity, such a behavior is not expected to occur in a Fermi liquid. We consider the anisotropic $t$-$J$ model with the c-axis pa

Clement Sire

In this letter, I solve a model for the dynamics of vortices in a decaying two-dimensional turbulent fluid. The model describes their effective diffusion, and the merging of pairs of vortices of same vorticity sign, when they get too close. The merging process is characterized by the conservation of energy and of the quantity $Nr^n$, where $r$ is the mean vo

Edouard Gorbar, Stefan Mashkevich, Sergei Sharapov

We consider particles in three-dimensional space, which have a certain probability to find themselves in a thin layer (``plane&#39;&#39;), where they are assumed to be well described by a planar Hamiltonian and are subject to Aharonov-Bohm-type interaction. We demonstrate that their planar motion is then anyonlike, with the ``effective statistical parameter&

J. A. Nieminen

Surface reconstructions of Au film on Pd(110) substrate are studied using a local Einstein approximation to quasiharmonic theory with the Sutton-Chen interatomic potential. Temperature dependent surface free energies for different coverages and surface structures are calculated. Experimentally observed transformations from $(1\times1)$ to $(1 \times 2)$ and

Subir Sachdev, Antoine Georges

We study the quantum transition from a strongly correlated metal, with heavy fermionic quasiparticles, to a metal with commensurate charge or spin density wave order. To this end, we introduce and numerically analyze a large dimensionality model of Ising spins in a transverse field, coupled to two species of fermions; the analysis borrows heavily from recent

R. Hilfer, N. B. Wilding

Critical finite-size scaling functions for the order parameter distribution of the two and three dimensional Ising model are investigated. Within a recently introduced classification theory of phase transitions, the universal part of the critical finite-size scaling functions has been derived by employing a scaling limit that differs from the traditional fin

K. Glazebrook, R. Ellis, M. Colless, T. Broadhurst

Using the multislit LDSS-2 spectrograph on the {\it William Herschel Telescope} we have completed a redshift survey in the magnitude range $22.5<B< 24$ which has produced 73 redshifts representing a 73\% complete sample uniformly-selected from four deep fields at high Galactic latitude. The survey extends out to $z>1$ and includes the highest redshift galaxy

Silvia Mollerach, Alejandro Gangui, Francesco Lucchin, Sabino Matarrese

We compute the contribution to the three--point temperature correlation function of the Cosmic Microwave Background coming from the non--linear evolution of Gaussian initial perturbations, as described by the Rees--Sciama (or integrated Sachs--Wolfe) effect. By expressing the collapsed three--point function in terms of multipole amplitudes, we are able to ca

L. Guzzo, K. B. Fisher, M. S. Strauss, R. Giovanelli

We present some new results from an ongoing investigation of the anisotropy of the two--point correlation function for optically selected galaxies. We have estimated xi(r_p,pi) from the Perseus-Pisces redshift survey, which is now virtually 100\% complete for all morphological types to m_B = 15.5. We detect strong distortions of the iso-correlation contours

Leovigildo Alonso, Ana Jeremías, Joseph Lipman

We prove a sheaf-theoretic derived-category generalization of Greenlees-May duality (a far-reaching generalization of Grothendieck&#39;s local duality theorem): for a quasi-compact separated scheme X and a &#34;proregular&#34; subscheme Z---for example, any separated noetherian scheme and any closed subscheme---there is a sort of sheafified adjointness betwe

Jim Friar

The impact of chiral symmetry on nuclear physics is discussed in the context of recent advances in the few-nucleon systems and of dimensional power counting. The tractability of few-nucleon calculations, illustrated by very recent solutions for $A = 2-6$, is shown to follow from power counting based on chiral Lagrangians. The latter predicts the suppression

Swapna Mahapatra, Karmadeva Maharana, Lambodar P. Singh

We investigate the tachyon-dilaton-metric system to study the &#34;graceful exit&#34; problem in string theoretic inflation, where tachyon plays the role of the scalar field. From the phase space analysis, we find that the inflationary phase does not smoothly connect to a Friedmann-Robertson-Walker (FRW) expanding universe, thereby providing a simple tachyon

H. Aratyn

Some new developments in constrained Lax integrable systems and their applications to physics are reviewed. After summarizing the tau function construction of the KP hierarchy and the basic concepts of the symmetry of nonlinear equations, more recent ideas dealing with constrained KP models are described. A unifying approach to constrained KP hierarchy based

E. V. Shuryak

We discuss available information about the instanton size distribution $d(ρ)$, which comes from lattice simulations and the interacting instanton liquid model. Not only they are remarkably consistent, but one can also reproduce $d(ρ)$ with an alternative idea, based on the infrared fixed point. We show, that lattice non-perturbative beta-function (for $bare$

Richard Earl

We find a complete set of relations for the rational cohomology ring of the moduli space of rank three stable bundles over a Riemann surface of genus g and also show that the Pontryagin ring vanishes in degree 12g-8 and greater. The results are obtained by introducing some &#39;dual&#39; Mumford relations and generalising Kirwan&#39;s proofs of the Mumford a

Juergen Audretsch, Rainer Mueller

We consider the influence of acceleration on the radiative energy shifts of atoms in Minkowski space. We study a two-level atom coupled to a scalar quantum field. Using a Heisenberg picture approach, we are able to separate the contributions of vacuum fluctuations and radiation reaction to the Lamb shift of the two-level atom. The resulting energy shifts for

Alessandro Drago, Manuel Fiolhais, Ubaldo Tambini

We study the equation of state (EOS) of quark matter at zero temperature, using the Color Dielectric Model (CDM) to describe confinement. Sensible results are obtained in the version of the CDM for which confinement is imposed {\it smoothly}. The two--phases version of the model turns out to give unrealistic results for the EOS. Chiral symmetry plays a margi

Fernando Cornet, Jose I. Illana

We point out that the cross-section for the process $e^+ e^- \to e^+ e^- τ^+ τ^-$ at LEP is large enough to allow for a study of the anomalous electromagnetic couplings of the $τ$ lepton. We show that the present bounds on the magnetic dipole moment can be improved and that competitive bounds can be obtained for the electric dipole moment using the data take

R. Combescot, X. Leyronas

We propose to explain the contradictory experimental evidence about the symmetry of the order parameter in $YBa_{2}Cu_{3}O_{7} $ by taking into account the coupling between planes and chains. This leads to an anticrossing of the plane and chain band. We include an attractive pairing interaction within the planes and a repulsive one between planes and chains,

Ulf H. Danielsson, Dario Grasso

In this paper we study the polarization tensor of photons in a QED plasma in the presence of a magnetic field. We do it both at vanishing and at finite temperature. We use two different methods to compute the polarization tensor components $Π^{μν}$ within the one-loop approximation. The first starts from the effective Lagrangian of the system and relates $Π^

Hyun Seok Yang, Bum-Hoon Lee

We explicitly construct the adjoint operator of coboundary operator and obtain the Hodge decomposition theorem and the Poincaré duality for the Lie algebra cohomology of the infinite-dimensional gauge transformation group. We show that the adjoint of the coboundary operator can be identified with the BRST adjoint generator $Q^{\dagger}$ for the Lie algebra c

G. P. Borghi, A. Girlando, A. Painelli, J. Voit

We study the role of non-adiabatic Holstein electron-phonon coupling on the neutral-ionic phase transition of charge transfer crystals which can be tuned from continuous to discontinuous, using exact numerical diagonalization. The variation of electronic properties through the transition is smoothed by nonadiabaticity. Lattice properties are strongly affecte

Itzhak Bars

The unitarity problem in curved spacetime is solved for the string described by the SL(2,R) WZW model. The spectrum is computed exactly and demonstratedto be ghost-free. The new features include (i) SL(2,R) left/right symmetrycurrents that have logarithmic cuts on the world sheet but that satisfy theusual local operator products or commutation rules, (ii) ph

A. N. Aleshaev, I. V. Pinayev, V. M. Popik, S. S. Serednyakov

A single electron circulating in a storage ring is a very peculiar object. Synchrotron radiation quantum fluctuation causes stohastic process in the synchrotron oscillation of an electron. The radiation from a undulator permits one to obtain discret moments of longitudional electron motion. Experiments with a single electron on on the VEPP-3 optical klystron