March 1993 arXiv papers — page 5

O. V. Teryaev

The "kinematical" resolution of the $U_A(1)$ problem is proposed. The cancellation of photonic and gluonic anomalies suggested by the t'Hooft consistency principle naturally explains the zero singlet contributions to the first moments of proton and photon spin structure functions. The new sum rule for the photon spin structure function is derived

A. Mishra H. Mishra, S. P. Misra

We derive here the equation of state for quark matter with a nontrivial vacuum structure in QCD at finite temperature and baryon density. Using thermofield dynamics, the parameters of thermal vacuum and the gluon condensate function are determined through minimisation of the thermodynamic potential, along with a self-consistent determination of the effective

V. Privman, C. R. Doering, H. L. Frisch

We develop an analytical diffusion-equation-type approximation scheme for the one-dimensional coagulation reaction A+A->A with partial reaction probability on particle encounters which are otherwise hard-core. The new approximation describes the crossover from the mean-field rate-equation behavior at short times to the universal, fluctuation-dominated behavi

R. Schack, C. M. Caves

We analyze a randomly perturbed quantum version of the baker's transformation, a prototype of an area-conserving chaotic map. By numerically simulating the perturbed evolution, we estimate the information needed to follow a perturbed Hilbert-space vector in time. We find that the Landauer erasure cost associated with this information grows very rapidly a

Philip Tuckey

Some time ago, Sorkin (1975) reported investigations of the time evolution and initial value problems in Regge calculus, for one triangulation each of the manifolds $R*S^3$ and $R^4$. Here we display the simple, local characteristic of those triangulations which underlies the structure found by Sorkin, and emphasise its general applicability, and therefore t

Darwin Chang, Wai-Yee Keung, Ivan Phillips

We investigate the possibility of detecting CP--odd angular correlations in the various decay modes of the neutral Higgs boson including the modes of a $ZZ$ pair, a $W^+W^-$ pair, or a heavy quark pair. It is a natural way to probe the CP character of the Higgs boson once it is identified. Final state interactions (i.e. the absorptive decay amplitude) is not

Yujiro Kawamata

We extend the minimal model theorem to the 3-dimensional schemes which are projective and have semistable reduction over the spectrum of a Dedekind ring.

T. S. Biro, E. van Doorn, B. Mueller, M. H. Thoma

We investigate the processes leading to phase-space equilibration of parton distributions in nuclear interactions at collider energies. We derive a set of rate equations describing the chemical equilibration of gluons and quarks including medium effects on the relevant QCD transport coefficients, and discuss their consequences for parton equilibration in hea

B. Q. Chen, P. Vogel

The interpretation of future precise experiments on atomic parity violation in terms of parameters of the Standard Model could be hampered by uncertainties in the atomic and nuclear structure. While the former can be overcome by measurement in a series of isotopes, the nuclear structure requires knowledge of the neutron density. We use the nuclear Hartree-Fo

Geoffrey Dixon

The tensor product of the division algebras, which is a kernel for the structure of the Standard Model, is also a root for the Clifford algebra of (1,9)-space-time. A conventional Dirac Lagrangian, employing the (1,9)-Dirac operator acting on the Standard Model hyperfield, gives rise to matter into antimatter transitions not mediated by any gauge field. Thes

M. A. Guest, Y. Ohnita

We obtain some new results on classical solutions of two dimensional Euclidean sigma models. From earlier work of Din-Zakrzewski, Glaser-Stora, and numerous differential geometers, one knows explicit solutions in the case of the $S^n$-model, the $CP^n$-model, and the $U(n)$-model. However, very little is known about the "moduli space" of solutions it

M. Furuta, M. A. Guest, M. Kotani, Y. Ohnita

We compute the fundamental group of the "moduli space" of classical solutions of the two dimensional Euclidean $S^n$-model.

C. Burdik, P. Hellinger

We give a construction of Drienfeld's quantum double for a nonstandard deformation of Borel subalgebra of $sl(2)$. We construct explicitly some simple representations of this quantum algebra and from the universal R-matrix we obtain the explicit solutions of the Yang-Baxter equation in those cases.

Fernando Martinez Moras, Javier Mas, Eduardo Ramos

Classical W-algebras in higher dimensions have been recently constructed. In this letter we show that there is a finitely generated subalgebra which is isomorphic to the algebra of local diffeomorphisms in D dimensions. Moreover, there is a tower of infinitely many fields transforming under this subalgebra as symmetric tensorial one-densities. We also unrave

M. Bernasconi, G. L. Chiarotti, E. Tosatti

We propose, based on ab initio calculations, that the ground state (001) surface of $α$-Ga should be covered by two layers of GaIII, a denser phase which is stable in the bulk only at high pressure and temperature. We discuss how this novel prediction can explain recent STM observations, including anomalous thermal stability of this surface.

J. Gonzalez, F. Guinea, M. A. H. Vozmediano

The screening properties of fullerene molecules are described by means of a continuum model which uses the electronic wavefunctions of planar graphite as a starting point. The long distance behavior of the system gives rise to a renormalizable theory, which flows towards a non trivial fixed point. Its existence implies an anomalous dielectric constant. The s

R. Schack

If p is the probability of a letter of a memoryless source, the length l of the corresponding binary Huffman codeword can be very different from the value -log p. We show that, nevertheless, for a typical letter, l is approximately equal to -log p. More precisely, the probability that l differs from -log p by more than m decreases exponentially with m.

H. Nishino

{}~~~We show that the recently constructed $~N=4$~ supersymmetric self-dual Yang-Mills theory as the consistent background of \hbox{$~N=2$} open superstring will generate Witten's topological field theory in two-dimensions as a descendant theory after appropriate twisted dimensional reduction/truncations. We also show that this topological field theory f

Daryl Grunau, Shiyi Chen, Kenneth Egger

We develop a lattice Boltzmann equation method for simulating multi-phase immiscible fluid flows with variation of density and viscosity, based on the model proposed by Gunstensen {\em et al} for two-component immiscible fluids. The numerical measurements of surface tension and viscosity agree well with theoretical predictions. Several basic numerical tests,

J. M. Cline, S. Paban

The program of induced QCD requires that there exist self-interactions among the heavy matter fields (an adjoint scalar and a few fermions in the fundamental representation) which tend to spoil the asymptotic freedom of SU(N) gauge theory. We consider general interactions between such matter fields and show that, on the contrary, to two loops, they all tend

Matt Visser

Considerable interest has recently been expressed in the entropy versus area relationship for ``dirty'' black holes --- black holes in interaction with various classical matter fields, distorted by higher derivative gravity, or infested with various forms of quantum hair. In many cases it is found that the entropy is simply related to the area of the

Cayetano Di Bartolo, Rodolfo Gambini, Jorge Griego

A set of coordinates in the non parametric loop-space is introduced. We show that these coordinates transform under infinite dimensional linear representations of the diffeomorphism group. An extension of the group of loops in terms of these objects is proposed. The enlarged group behaves locally as an infinite dimensional Lie group. Ordinary loops form a su

Guido Cognola, Luciano Vanzo

The heat coefficients related to the Laplace-Beltrami operator defined on the hyperbolic compact manifold $H^3/\Ga$ are evaluated in the case in which the discrete group $\Ga$ contains elliptic and hyperbolic elements. It is shown that while hyperbolic elements give only exponentially vanishing corrections to the trace of the heat kernel, elliptic elements m

Jeffrey M. Grandy, Michael P. Mattis

The valley method for computing the total high-energy anomalous cross section $S_{anom}$ is the extension of the optical theorem to the case of instanton-antiinstanton backgrounds. As a toy model for baryon number violation in Electroweak theory, we consider a version of the $O(3)$ $σ$ model in which the conformal invariance is broken perturbatively. We show

G. Bathas, W. M. Kloet

Within the quark model a generalization is proposed of the commonly used annihilation potential to describe antiproton-proton annihilation into two mesons, the so-called $^3P_0$ and $^3S_1$ mechanisms. This generalized potential treats the two mechanisms in a more symmetric way, has additional angular dependence, and results in an expanded set of selection r

Charles P. Stegall

A remarkable theorem of R. C. James is the following: suppose that $X$ is a Banach space and $C \subseteq X$ is a norm bounded, closed and convex set such that every linear functional $x^* \in X^*$ attains its supremum on $C$; then $C$ is a weakly compact set. Actually, this result is significantly stronger than this statement; indeed, the proof can be used

A. Yu. Alekseev, A. Z. Malkin

The Lie-Poisson analogues of the cotangent bundle and coadjoint orbits of a Lie group are considered. For the natural Poisson brackets the symplectic leaves in these manifolds are classified and the corresponding symplectic forms are described. Thus the construction of the Kirillov symplectic form is generalized for Lie-Poisson groups.

Abbas Ali, Alok Kumar

We generalize the results of a previous paper by one of the authors to show a relationship among a class of string solutions through $O(\tilde d, \tilde d)$ transformations. The results are applied to a rotating black hole solution of three dimensional general relativity discussed recently. We extend the black hole solution to string theory and show its conn

A. Cappelli, C. A. Trugenberger, G. R. Zemba

The Laughlin states for $N$ interacting electrons at the plateaus of the fractional Hall effect are studied in the thermodynamic limit of large $N$. It is shown that this limit leads to the semiclassical regime for these states, thereby relating their stability to their semiclassical nature. The equivalent problem of two-dimensional plasmas is solved analyti

Frank De Jonghe

Implementing the requirement that a field theory be invariant under Schwinger-Dyson BRST symmetry in the Hamiltonian formalism, we show the equivalence between Hamiltonian and Lagrangian BRST-formalism at the path integral level. The Lagrangian quantum master equation is derived as a direct consequence of the Fradkin-Vilkovisky theorem in Hamiltonian BRST qu

A. S. Gorsky, A. V. Zabrodin

A new trigonometric degeneration of the Sklyanin algebra is found and the functional realization of its representations in space of polynomials in one variable is studied. A further contraction gives the standard quantum algebra $U_{q}(sl(2))$. It is shown that the degenerate Sklyanin algebra contains a subalgebra isomorphic to algebra of functions on the qu

O. K. Kalashnikov

The nonanalytic $g^3$-term is calculated for SU(2)-effective action at finite temperature and the status of a gauge fields condensation is briefly discussed.

O. K. Kalashnikov

The two-loop effective action for the SU(3) gauge model in a constant background field ${\bar A}_0(x,t)=B_0^3T_3+B_0^8T_8$ is recalculated for a gauge with an arbitrary $ξ$-parameter. The gauge-invariant thermodynamical potential is found and its extremum points are investigated. Within a two-loop order we find that the stable nontrivial vacuum is completely

L. Littenberg, G. Valencia

We review the status of theory and experiment of very rare and forbidden kaon decays. We then review the radiative non-leptonic decays, and the associated Dalitz pair modes. We pay particular attention to the study of long distance physics in radiative decays within the framework of chiral perturbation theory ($χ$PT). We discuss the experiments that will run

Wolfgang Kilian, Thomas Mannel, Thorsten Ohl

We argue that the imaginary parts of the anomalous dimensions in the multiparticle sectors of heavy quark effective field theory may be removed by a suitable redefinition of the multiparticle states. The connection between the imaginary parts of the anomalous dimensions and the interquark potential is pointed out

A. K. Likhoded, S. R. Slabospitsky, M. Mangano, G. Nardulli

In this paper we summarize the results of the theory working group dedicated to the analysis of $B_c$ production at hadron colliders.

G. Nardulli

CP violations in B meson decays at hadron colliders are reviewed. In particular I examine: $B^0-\bar{B^0}$ mixing and oscillations within Standard Model and the Cabibbo-Kobayashi-Maskawa picture for CP violations; $B^0$ decays into CP eigenstates and the measurements of the angles in the unitarity triangle; finally I consider a class of charged $B$ decays th

Abdellatif Abada, Houari Merabet

We study an extended Skyrme model which includes fourth and sixth-order terms. We explore some static properties like the $Δ$-nucleon mass splitting and investigate the Skyrmion breathing mode in the framework of the linear response theory. We find that the monopole response function has a pronounced peak located at $\sim$ 400 MeV, which we identify to the R

P. Colangelo, G. Nardulli, N. Paver

We review some recent applications of QCD sum rules to $B$-decays. These include the determination of the leptonic constant $f_B$ and of the semileptonic transition amplitudes of the $B$-meson into negative and positive parity charmed states.

C. Csáki, F. Csikor

The three generation mirror fermion model is compared with LEP precision and low energy data. While for zero mixing of ordinary and mirror fermions the model is not favoured, for non zero mixing very low $χ^2 $ fits have been obtained, in particular when right handed leptonic mixings are small and left handed leptonic mixings are large (of the order of 0.1 r

Gyan Bhanot, Michael Creutz, Ivan Horvath Jan Lacki, John Weckel

We discuss the use of recursive enumeration schemes to obtain low and high temperature series expansions for discrete statistical systems. Using linear combinations of generalized helical lattices, the method is competitive with diagramatic approaches and is easily generalizable. We illustrate the approach using the Ising model and generate low temperature s

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

We investigate the recent conjecture that the chiral phase transition in non-compact lattice QED is driven by monopole condensation. The comparison of analytic and numerical results shows that we have a quantitative understanding of monopoles in both the quenched and dynamical cases. We can rule out monopole condensation.

Abdellatif Abada, Dominique Vautherin

Two phonon-states of alkali-metal clusters (treated as jellium spheres) are calculated by using a method based on a perturbative construction of periodic orbits of the time-dependent mean-field equations. Collective vibrations with various multipolarities in charged $Na^+_{21}$ are considered.

Shiyi Chen, Gary Doolen, Jackson R. Herring, Robert H. Kraichnan

The very small scales of isotropic, Navier-Stokes turbulence at Reynolds number ${\cal R}_λ\approx 15$ are studied by high-resolution direct numerical simulation (DNS) and by integration of the direct-interaction (DIA) equations. The DNS follows the tail of the energy spectrum over more than thirty decades of magnitude. The energy spectrum in the far-dissipa

Pavel Etingof

There were some errors in paper hep-th/9303018 in formulas 6.1, 6.6, 6.8, 6.11. These errors have been corrected in the present version of this paper. There are also some minor changes in the introduction.

P. Mayr, S. Stieberger

We derive the moduli dependent threshold corrections to gauge couplings in toroidal orbifold compactifications. The underlying six dimensional torus lattice of the heterotic string theory is not assumed ---as in previous calculations--- to decompose into a direct sum of a four--dimensional and a two--dimensional sublattice, with the latter lying in a plane l

E. Laenen, S. Riemersma, J. Smith, W. L. van Neerven

We examine the QCD corrections to the structure functions $F_2^γ(x,Q^2)$ and $F_L^γ(x,Q^2)$ for a real photon target. The pointlike photon contributions from light and heavy quarks are computed through $O(αα_S)$. A parameterization of the hadronic (resolved) photon contribution is also included and a comparison is made with the present experimental data. We

Maximilian Kreuzer

The recent classification of Landau--Ginzburg potentials and their abelian symmetries focuses attention on a number of models with large positive Euler number for which no mirror partner is known. All of these models are related to Calabi--Yau manifolds in weighted $\IP_4$, with a characteristic structure of the defining polynomials. A closer look at these p

Nathan Berkovits

The sigma model action described in this paper differs in four important features from the usual sigma model action for the four-dimensional Green-Schwarz heterotic superstring in a massless background. Firstly, the action is constructed on an N=(2,0) super-worldsheet using a Kahler potential and an Ogievetsky-Sokatchev constraint; secondly, the target-space

J. Garriga, M. Sakellariadou

We study the evolution of cosmic strings taking into account the frictional force due to the surrounding radiation. We consider small perturbations on straight strings, oscillation of circular loops and small perturbations on circular loops. For straight strings, friction exponentially suppresses perturbations whose co-moving scale crosses the horizon before

Matt Visser

The recent renaissance of wormhole physics has led to a very disturbing observation: If traversable wormholes exist then it appears to be rather easy to to transform such wormholes into time machines. This extremely disturbing state of affairs has lead Hawking to promulgate his chronology protection conjecture. This paper continues a program begun in an earl

Matt Visser

The van Vleck determinant is an ubiquitous object, arising in many physically interesting situations such as: (1) WKB approximations to quantum time evolution operators and Green functions. (2) Adiabatic approximations to heat kernels. (3) One loop approximations to functional integrals. (4) The theory of caustics in geometrical optics and ultrasonics. (5) T

Victor Tapia

We consider the conformal properties of geometries described by higher-rank line elements. A crucial role is played by the conformal Killing equation (CKE). We introduce the concept of null-flat spaces in which the line element can be written as ${ds}^r=r!dζ_1\cdots dζ_r$. We then show that, for null-flat spaces, the critical dimension, for which the CKE has

S. Hirano, Y. Kazama, Y. Satoh

Exact operator quantization is perfomed of a model of two-dimensional dilaton gravity in Lorentzian spacetime, classically equivalent to the one proposed by Callan, Giddings, Harvey and Strominger, in the special case with 24 massless matter scalars. This is accomplished by developing a non-linear and non-local quantum canonical transformation of basic inter

Lawrence J. Hall

Has any progress been made on understanding and predicting the 13 parameters which describe the observed masses and mixing angles of the quarks and leptons? Arguments are given in favor of pursuing schemes in which grand unified and family symmetries provide many relations among these 13 parameters. A sequence of simple assumptions leads to a supersymmetric

John F. Gunion, T. C. Yuan, B. Grzadkowski

We demonstrate that CP violation in the Higgs sector, \eg\ of a multi-doublet model, can be directly probed using gluon-gluon collisions at the SSC. % requires phyzzx.tex macro package

U M. Heller, M. Klomfass, H. Neuberger, P. Vranas

Previous large $N$ calculations are combined with numerical work at $N=4$ to show that the Minimal Standard Model will describe physics to an accuracy of a few percent up to energies of the order 2 to 4 times the Higgs mass, $M_H$, only if $M_H \le 710\pm60 ~ GeV$. This bound is the result of a systematic search in the space of dimension six operators and is

Chr. V. Christov, E. Ruiz Arriola, K. Goeke

Modifications of baryon properties due to the restoration of the chiral symmetry in an external hot and dense baryon medium are investigated in an effective chiral quark-meson theory. The nucleon arises as a soliton of the Gell-Mann - Lévi $\zs$-model, the parameters of which are chosen to be the medium-modified meson values evaluated within the Nambu - Jona

Chr. V. Christov, K. Goeke

The solitonic sector of the Nambu - Jona-Lasinio model with baryon number one is solved in the presence of an external medium. The calculations fully include the polarization of both the Dirac sea and the medium as well as the Pauli blocking effect. We found that with an increasing density the medium destabilizes the soliton. At finite medium density the sol

Chr. V. Christov

The Nambu - Jona-Lasinio model in its SU(2) and SU(3) versions with scalar and pseudoscalar coupling are applied to baryons. The parameters of the model are fixed in the meson sector. The baryons arise as a soliton of three valence quarks coupled to the Dirac sea (quark-antiquarks pairs). Within the SU(2) version the nucleon static properties as well as some

F. Buccella, F. Lombardi, G. Miele, P. Santorelli

The Cabibbo allowed non-leptonic $B$-decays in two hadrons are studied, within the factorization hypothesis, in the framework of Isgur and Wise theory for the matrix elements of the $ΔB=-ΔC=\pm 1$ weak currents. The $SU(2)_{HF}$ symmetry relates $|ΔB|=1$ to $|ΔC|=1$ currents, which have been measured in the semileptonic strange decays of charmed particles. B

G. Mangano, F. Sannino

A suggestive phenomenological relation is found among the lepton and quark masses which suggests a new insight into the problem of generations and also gives a prediction for the top quark mass in agreement with the range of values which is actually expected.

P. Bialas, J. G. Koerner, K. Zalewski

We develop a general algorithm for describing angular decay distributions in cascade decay chains of arbitrary length. The general algorithm is used to study joint angular decay distributions for the cascade decay $B\rightarrow D^{**}( \rightarrow D^*(\rightarrow D π)+π) + W(\rightarrow lν)$ where the $D^{**}$ is a generic $P$-wave charm meson state. Lepton

Kumar S. Gupta, M. Arshad Momen, J. Schechter, A. Subbaraman

We investigate the heavy baryons which arise as solitonic excitations in a ``heavy meson" chiral Lagrangian which includes the light vector particles. It is found that the effect of the light vectors may be substantial. We also present a simple derivation which clearly shows the connection to the Callan-Klebanov approach.

Victor Tapia, A. L. Marrakchi, M. Cataldo

We consider the consequences of describing the metric properties of space- time through a quartic line element $ds^4=G_{μνλρ}dx^μdx^νdx^λdx^ρ$. The associated "metric" is a fourth-rank tensor $G_{μνλρ}$. We construct a theory for the gravitational field based on the fourth-rank metric $G_{μνλρ}$ which is conformally invariant in four dimensions. In t

R. S. Markiewicz

The low-temperature orthorhombic (LTO) phase transition in La$_{2-x}$Sr$_x$CuO$_4$ can be interpreted as a dynamic Jahn-Teller effect, in which the degenerate electronic states are associated with the large densities of states at the two van Hove singularities. The equations describing this phase are strongly nonlinear. This paper illustrates some consequenc

R. S. Markiewicz

The possible role of the van Hove singularity (vHs) in stabilizing the low-temperature orthorhombic (LTO) phase transition in La$_{2-x}$\-Sr$_x$\-CuO$_ 4$ (LSCO) is discussed. It is found that the vHs can drive a structural distortion in two different ways, either due to spin-orbit coupling or to dynamic Jahn-Teller (JT) effects. This paper discusses the lat

Ronnie Mainieri

By viewing the covers of a fractal as a statistical mechanical system, the exact capacity of a multifractal is computed. The procedure can be extended to any multifractal described by a scaling function to show why the capacity and Hausdorff dimension are expected to be equal.

M. Ferraris, M. Francaviglia, I. Volovich

It is shown that for a wide class of analytic Lagrangians which depend only on the scalar curvature of a metric and a connection, the application of the so--called ``Palatini formalism'', i.e., treating the metric and the connection as independent variables, leads to ``universal'' equations. If the dimension $n$ of space--time is greater than

C. O. Lousto, N. Sanchez

We study the quantization of the curved spacetime created by ultrarelativistic particles at Planckian energies. We consider a minisuperspace model based on the classical shock wave metric generated by these particles, and for which the Wheeler - De Witt equation is solved exactly. The wave function of the geometry is a Bessel function whose argument is the c

John Ellis, David N. Schramm

We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by palaeontologists. We discuss the likely rate of such events in the light of the recent identification of Geminga as a supernova remnant less than 100 pc away and the discovery of a millisecond pulsar about 150 pc away, and observat

Sean A. Hayward

A general definition of a black hole is given, and general `laws of black-hole dynamics' derived. The definition involves something similar to an apparent horizon, a trapping horizon, defined as a hypersurface foliated by marginal surfaces of one of four non-degenerate types, described as future or past, and outer or inner. If the boundary of an inextend

N. Kaloper

Some aspects of the rotating three-dimensional Einstein-Anti-de-Sitter black hole solution, constructed recently by Banados, Teitelboim and Zanelli are discussed. It is shown explicitly that this black hole represents the most general black hole type solution of the Einstein-Anti-de-Sitter theory. The interpretation of one of the integrals of motion as the s

S. E. Thorsett, Z. Arzoumanian, M. M. McKinnon, J. H. Taylor

The measurement or constraint of the masses of neutron stars and their binary companions tests theories of neutron star structure and of pulsar formation and evolution. We have measured the rate of the general relativistic advance of the longitude of periastron for the pulsar PSR B1802$-$07: $\dotω=0\fdg060\pm0\fdg009\,\mbox{yr}^{-1}$, which implies a total

S. Dasmahapatra, R. Kedem, T. R. Klassen, B. M. McCoy

We review recent results concerning the representation of conformal field theory characters in terms of fermionic quasi-particle excitations, and describe in detail their construction in the case of the integrable three-state Potts chain. These fermionic representations are $q$-series which are generalizations of the sums occurring in the Rogers-Ramanujan id

J. J. M. Verbaarschot, I. Zahed

We investigate the spectral properties of a random matrix model, which in the large $N$ limit, embodies the essentials of the QCD partition function at low energy. The exact spectral density and its pair correlation function are derived for an arbitrary number of flavors and zero topological charge. Their microscopic limit provide the master formulae for sum

M. Schiffer

In the framework of communication theory, we analyse the gedanken experiment in which beams of quanta bearing information are flashed towards a black hole. We show that stimulated emission at the horizon provides a correlation between incoming and outgoing radiations consisting of bosons. For fermions, the mechanism responsible for the correlation is the Fer

Chang_Pu Sun

By building a general dynamical model for quantum measurement process,it is shown that the factorization of reduced evolution operator sufficiently results in the quantum mechanical realization of the wave packet collapse and the state correlation between the measured system and the measuring instrument-detector.This realizability is largely independent of t

Peter Bantay

: Algebraic properties of orbifold models on arbitrary Riemann surfaces are investigated. The action of mapping class group transformations and of standard geometric operations is given explicitly. An infinite dimensional extension of the quantum group is presented.

V. I. Man'ko, G. Marmo, S. Solimeno, F. Zaccaria

Nonlinearity of electromagnetic field vibrations described by q-oscillators is shown to produce essential dependence of second correlation functions on intensity and deformation of Planck distribution. Experimental tests of such nonlinearity are suggested.

Hikaru Kawai, Ryuichi Nakayama

Two-dimensional quantum gravity with an $R^2$ term is investigated in the continuum framework. It is shown that the partition function for small area $A$ is highly suppressed by an exponential factor $exp \{ -2π(1-h)^2/(m^2A) \}$, where $1/m^2$ is the coefficient (times $32π$) of $R^2$ and $h$ is the genus of the surface. Although positivity is violated, at

Eric Braaten, Tzu Chiang Yuan

The dominant production mechanism for heavy quark-antiquark bound states in very high energy processes is fragmentation, the splitting of a high energy parton into a quarkonium state and other partons. We show that the fragmentation functions $D(z,μ)$ describing these processes can be calculated using perturbative QCD. We calculate the fragmentation function

Bohdan Grzcadkowski

The general production {\it and} decay mechanism of $\ttbar$ in future high-energy $\epem$ colliders has been investigated in a model-independent way, focusing on an observation of possible CP violation. Angular asymmetries sensitive to CP violation either in the production {\it or} in the subsequent decays have been found. General considerations are illustr

J. P. Ma, B. H. J. McKellar

We study the possibility to test CP invariance in the $W^+W^-$ production via photon fusion at NLC. The predictions of the CP violation effects are made within two Higgs doublet extensions of the minimal standard model, where CP violation is introduced by a neutral Higgs exchange in s channel in our case. The width effect in the Higgs propagator on the CP vi

Don N. Page

The apparent superluminal growth in the size of a sufficiently large part of the universe can be ascribed to the special relativistic effect of time dilation.

C. Farina, J. Gamboa, A. J. Segui-Santonja

The motion of relativistic particles around three dimensional black holes following the Hamilton-Jacobi formalism is studied. It follows that the Hamilton-Jacobi equation can be separated and reduced to quadratures in analogy with the four dimensional case. It is shown that: a) particles are trapped by the black hole independently of their energy and angular

G. Chu, Jorge V. Jose

We present a detailed study of the dynamic response of a ring of $N$ equally spaced Josephson junctions to a time-periodic external flux, including screening current effects. The dynamics are described by the resistively shunted Josephson junction model, appropriate for proximity effect junctions, and we include Faraday's law for the flux. We find that t

J. Boronat, F. Dalfovo, F. Mazzanti, A. Polls

Relevant features of the dynamic structure function $S(q,ω)$ in $^3$He-$^4$He mixtures at zero temperature are investigated starting from known properties of the ground state. Sum rules are used to fix rigorous constraints to the different contributions to $S(q,ω)$, coming from $^3$He and $^4$He elementary excitations, as well as to explore the role of the c

Rudolf A. R"omer, Bill Sutherland

We show how conformal invariance predicts the functional form of two-point correlators in one-dimensional periodic quantum systems. Numerical evidence for this functional form in a wide class of models --- including long-ranged ones --- is given and it is shown how this may be used to significantly speed up calculations of critical exponents.

Andreas Albrecht, Pedro Ferreira, Michael Joyce, Tomislav Prokopec

The inflationary cosmology is analyzed from the point of view of squeezed quantum states. As noted by Grishchuk and Sidorov, the amplification of quantum fluctuations into macroscopic perturbations which occurs during cosmic inflation is a process of quantum squeezing. We carefully develop the squeezed state formalism and derive the equations that govern the

S. Kamerdzhiev, J. Speth, G. Tertychny, J. Wambach

Within a microscopic approach which takes into account RPA configurations, the single-particle continuum and more complex $1p1h\otimes phonon$ configurations isoscalar and isovector M1 excitations for the unstable nuclei ${56,78}$Ni and ${100,132}$Sn are calculated. For comparison, the experimentally known M1 excitations in ${40}$Ca and $^{208}$Pb have also

A. A. Andrianov, M. V. Ioffe, V. P. Spiridonov

Higher-derivative generalization of the supersymmetric quantum mechanics is proposed. It is formally based on the standard superalgebra but supercharges involve differential operators of the order $n$. As a result, their anticommutator entails polynomial of a Hamiltonian. The Witten index does not characterize spontaneous supersymmetry breaking in such model

V. Spiridonov

An application of the particular type of nonlinear operator algebras to spectral problems is outlined. These algebras are associated with a set of one-dimensional self-similar potentials, arising due to the q-periodic closure f_{j+N}(x)=qf_j(qx), k_{j+N}=q^2 k_j of a chain of coupled Riccati equations (dressing chain). Such closure describes q-deformation of

Dieter Luest

Talk given at the 26th Workshop: ``From Superstrings to Supergravity" Erice - Sicily, 5-12 December 1992: In this talk we discuss string consistency requirements on four dimensional string models, namely the cancellation of target space duality anomalies. The analysis is explicitly performed for (hypothetical) orbifold models assuming the massless spectr

Ulf H. Danielsson

A quantum version of 2D super dilaton gravity containing a black hole is constructed for $N>8$. A previous disagreement as to whether this is possible or not is resolved.

Arne L. Larsen, Valery P. Frolov

A covariant formalism for physical perturbations propagating along a string in an arbitrary curved spacetime is developed. In the case of a stationary string in a static background the propagation of the perturbations is described by a wave-equation with a potential consisting of 2 terms: The first term describing the time-dilation and the second is connecte

M. Carena, S. Pokorski, C. E. M. Wagner

The unification of gauge and Yukawa couplings within the minimal supersymmetric standard model is studied at the two loop level. We derive an expression for the effective scale, $T_{SUSY}$, which characterizes the supersymmetric particle threshold corrections to the gauge couplings, and demonstrate that $T_{SUSY}$ is only slightly dependent on the squark and

R. Casalbuoni, P. Chiappetta, A. Deandrea, S. De Curtis

We explore the usefulness of very energetic linear $e^+e^-$ colliders in the $TeV$ range in studying an alternative scheme of electroweak symmetry breaking based on a strong interacting sector. The calculations are performed within the BESS model which contains new vector resonances. If the mass $M_V$ of the new boson multiplet lies not far from the maximum

A. Burinskii

The Kerr geometry is represented as being created by a source moving along an analytical complex world-line. The equivalence of this complex world-line and an Euclidean version of complex strings (hyperbolic strings) is discussed. It is shown that the complex Kerr source satisfies the corresponding string equations. The boundary conditions of the complex Euc

Tevian Dray, Corinne A. Manogue, Robin W. Tucker

We consider the (massless) scalar field on a 2-dimensional manifold with metric that changes signature from Lorentzian to Euclidean. Requiring a conserved momentum in the spatially homogeneous case leads to a particular choice of propagation rule. The resulting mix of positive and negative frequencies depends only on the total (conformal) size of the spaceli