bluuebunny/crossref_metadata_2025 huggingface dataset:
STATISTICS IN ONE DIMENSION: HEISENBERG AND SCHRÖDINGER QUANTIZATIONS
Authors: ISAKOV SERGEI B.
Published: November 2004

We show that Heisenberg quantization of a system of two identical particles in one dimension recently proposed by Leinaas and Myrheim leads to the family of 1D fractional statistics introduced by Polychronakos in terms of Schrödinger quantization.
FIVE-DIMENSIONAL ABELIAN CHERN-SIMONS THEORY IN TERMS OF LINKING NUMBER
Authors: GUSIN PAWEL
Published: November 2004

We discuss Ward identities in five-dimensional Abelian Chern-Simons theory. Using the Ward identities we calculate correlation functions of some field variables which are invariant under diffeomorphisms and gauge transformations. We show that the correlation functions are expressed by the linking number.
SOLITONS AND BUBBLES IN MODELS WITH CHERN-SIMONS TERM
Authors: MASPERI L.
Published: November 2004

It is shown that a gauge theory for complex scalar field with up to sextic self-interactions and a Chern-Simons term in 2+1 dimensions has solitons which may become bubbles of the stable broken-symmetry phase in a medium of the symmetric one producing the first order phase transition. In the non-relativistic limit scale invariance prevents the determination of an optimal bubble size. Possible extensions to 3 + 1 dimensions of bubbles of string type are indicated.
TWO-DIMENSIONAL BARYONS IN THE LARGE-N LIMIT
Authors: BEDAQUE P.F. , HORVATH I. , RAJEEV S.G.
Published: November 2004

We propose a bilocal field theory for mesons in two dimensions obtained as a kind of non-local bosonization of two-dimensional QCD. Its semiclassical expansion is equivalent to the 1/Nc expansion of QCD. Using an ansatz we reduce the classical equation of motion of this theory in the baryon number one sector to a relativistic Hartree equation and solve it numerically. This (non-topological) soliton is identified with the baryon.
A REMARK ON QUANTUM SUPERGROUPS
Authors: HLAVATÝ LADISLAV
Published: November 2004

The relations for the algebras that leave the quantum space and its superdual invariant are written. It is shown that they can differ from supersymmetric version of the Faddeev, Reshetikhin, Takhtajan relation. As an example alternative deformations of GL(1|1) are presented.
PAIR CORRELATOR IN THE ITZYKSON-ZUBER INTEGRAL
Authors: MOROZOV A.
Published: November 2004

An explicit expression is suggested for the average [Formula: see text] over the unitary group SU (N) with the Itzykson-Zuber measure [dU] exp tr ΦUΨU†.
TIME-SPACE DEPENDENT FORMULATION IN THERMOFIELD DYNAMICS
Authors: NAKAMURA K. , UMEZAWA H. , YAMANAKA Y.
Published: November 2004

The recently developed formulation of time-dependent non-equilibrium thermofield dynamics (TFD) is extended to spatially inhomogeneous field systems in this paper. This inhomogeneous formalism is constructed from introducing momentum mixing thermal Bogoliubov transformation. The momentum mixing number density in the Bogoliubov matrix is related to the number density distribution defined at each space-time point which is to be observed.
A NOTE ON N=2 SUPERSTRINGS
Authors: BIEŃKOWSKA J.R. , LU H.
Published: November 2004

In this note we investigate the generalized critical N=2 superstrings in (1, 2p) spacetime signature. We calculate the four-point functions for the tachyon operators of these theories. In contrast to the usual N=2 superstring in (2, 2) space-time, the four-point functions do not vanish. The exchanged particles of the four-point function are included in the physical spectrum of the corresponding theory and have vanishing fermion charge.
AREA PRESERVING DIFFEOMORPHISMS AND W∞ SYMMETRY IN A 2+1 CHERN-SIMONS THEORY
Authors: KOGAN IAN I.
Published: November 2004

We discuss the W∞ symmetry in the 2+1 gauge theory with the Chern-Simons term. It is shown that the generators of this symmetry act on the ground state as the canonical transformations in the phase space. We shall also discuss the analogy between discrete states in c=1 string theory and Landau level states in 2+1 gauge theory with Chern-Simons term.
COMMENT ON THE TRACE ANOMALY IN STOCHASTIC QUANTIZATION
Authors: NAKAZAWA NAOHITO
Published: November 2004

We investigate the origin of the trace (conformal) anomaly in the context of stochastic quantization. Based on the Langevin equation, we study the local Ward-Takahashi identities corresponding to the Weyl invariance and the general coordinate invariance. It is shown that the Ito's stochastic calculus essentially picks up the non-trivial Jacobian factor which appears in the path-integral measure. We also provide how to construct the Langevin equation which maintains the general coordinate invariance in consistent with the Ito's calculus.
FURTHER TOPOLOGICAL PROOFS OF GRIBOV AMBIGUITIES
Authors: JUNGMAN GERARD
Published: November 2004

We show the existence of Gribov ambiguity for gauge group SU (N) and large classes of space-time manifolds with dimension less than or equal to four, working in the continuous category, extending previous results of Singer. In lower dimensions, and in four dimensions with gauge group SU (N), N≥3, we require only that the manifold be compact and orientable. In four dimensions with gauge group SU (2) there is a slight complification due to the fact that π4( SU (2)) does not vanish, though we are still able to state a useful result for that case. Some discussion of motivation is presented, in particular as regards to recent gauge-fixing proposals which arise in work that attempts to relate the Gribov ambiguity to confinement.
LARGE SCALE STRUCTURE BY GLOBAL MONOPOLES AND COLD DARK MATTER
Authors: PERIVOLAROPOULOS LEANDROS
Published: November 2004

A cosmological model in which the primordial perturbations are provided by global monopoles and in which the dark matter is cold has several interesting features. The model is normalized by choosing its single parameter within the bounds obtained from gravitational wave constraints and by demanding coherent velocity flows of about 600 km/sec on scales of 50h-1 Mpc . Using this normalization, the model predicts the existence of dominant structures with mass 2×1016M⊙ on a scale 35h-1 Mpc , i.e., larger than the horizon at t ep . The magnitude of the predicted mass function in the galactic mass range is in good agreement with the observed Schechter function.
SPONTANEOUS COMPACTIFICATION IN 2D INDUCED QUANTUM GRAVITY
Authors: ELIZALDE E. , ODINTSOV S. D.
Published: November 2004

Spontaneous compactification – on a R1 × S1 background – in 2D induced quantum gravity (considered as a toy model for more fundamental quantum gravity) is analyzed in the gauge-independent effective action formalism. It is shown that such compactification is stable, in contradistinction to multidimensional quantum gravity on a RD × S1(D > 2) background – which is known to be one-loop unstable.
FROZEN STATE IN QUANTIZED CHIRAL SOLITON WITH FOUR- AND SIX-DERIVATIVE TERMS
Authors: SAWADA SHOJI , YANG KEYAN
Published: November 2004

By the use of a family of trial functions for the profile function of the hedgehog ansatz it is shown that the frozen states also appear in the modified Skyrme model with six-derivative term. However, for a reasonable choice of parameters of the Skyrme term and of the six derivatives term, the quantized chiral solitons with I=J=1/2 and 3/2 do not lie on the frozen region.
A CONNECTION OF INELASTICITY WITH MULTIPLICITY DISTRIBUTION AT HIGH ENERGIES
Authors: GOLYAK ISAY
Published: November 2004

The widely known experimental value of the mean coefficient of the inelasticity ~0.5 is calculated by the investigation of a connection of the inelasticity with KNO scaling invariant multiplicity distributions of secondary particles.
CONCERNING THE DOUBLE SCALING LIMIT IN THE O(N) VECTOR MODEL IN FOUR DIMENSIONS
Authors: SCHNITZER HOWARD J.
Published: November 2004

The 1/N expansion for the O(N) vector model in four dimensions is reconsidered. It is emphasized that the effective potential for this model becomes everywhere complex just at the critical point, which signals an unstable vacuum. Thus a critical O(N) vector model cannot be consistently defined in the 1/N expansion for four dimensions, which makes the existence of a double-scaling limit for this theory doubtful.
MIXING EFFECTS IN SUPERNOVA PROCESSES WITH RIGHT-HANDED NEUTRINOS
Authors: HORVAT R.
Published: November 2004

The right-handed chiral component of the Dirac neutrino field in a dense medium is derived for two generation mixing. As an application, the modification factor on the luminosity of a supernova core is given for ν+ emission by neutrino-magnetic-moment and neutrino-charge-radius interactions.
POSSIBLE CONSEQUENCES OF PARITY CONSERVATION
Authors: FOOT R. , LEW H. , VOLKAS R. R.
Published: November 2004

It has been shown that parity may be an exact unbroken symmetry of nature. This requires a doubling of the number of physical particles, although only two parameters beyond those in the Standard Model are introduced. We show that the Lagrangian describing parity conserving models can be reformulated in terms of a basis in which each term of the Lagrangian is parity invariant, although gauge invariance is not manifest. We then examine some further experimental signatures of parity conservation. We point out that, in the simplest case, there is one parity-even and one parity-odd physical neutral Higgs mass eigenstate, whose Yukawa coupling constants are [Formula: see text]-that of the Standard Model Higgs boson. Furthermore, half of their widths are generated by almost invisible decay modes. Also, if neutrinos are massive then the ordinary and mirror neutrinos will, in the minimal case, be maximally mixed due to parity conservation. This means that vacuum oscillations can be large, thus providing a possible solution to the solar neutrino problem.
CONNECTIONS BETWEEN THE QUANTUM HALL EFFECT AND CONFORMAL FIELD THEORY
Authors: NAGAO GREG , NIU QIAN , GAITE JOSÉ
Published: November 2004

The quantum Hall effect (QHE) is studied in the context of a conformal field theory (CFT). Winding state vertex operators for an effective field of N "spins" associated with the cyclotron motion of particles are defined. The effective field of spins may be used to define an effective Hamiltonian. This effective Hamiltonian describes the collective motion of the N particles (with coupling κ0) together with a current-current interaction (of strength κ1). Such a system gives rise to a CFT in the large-N limit when κ0=κ1. The Laughlin wave function is derived from this CFT as an N'-point correlation function of winding state vertex operators.
CRITICAL BEHAVIOR IN THE MODEL OF RANDOM SURFACES WITH DYNAMICAL HOLES EMBEDDED IN −2- AND 1-DIMENSIONAL SPACES
Authors: BOULATOV D.V.
Published: November 2004

The model of discretized random surfaces with dynamical holes recently proposed by V.A. Kazakov for D=0 is considered for nontrivial embeddings, the cases D=−2 and 1 being exactly solvable. The model has two new parameters: the fugacity for the number of the holes ξ and a mass of scalar particles moving along their borders m. At m=mc the mean length of the borders and the mean number of the holes undergo the phase transition — related to an explosion of the holes — becoming singular at ξ=0. The singularity still exists for m<mc where the phase of “completely torn” surfaces takes place. The correspondent critical exponents are calculated.
THE CONSTRUCTION OF LEFT- AND RIGHT-HANDED CHIRAL SUPERFIELDS IN (1, ½) + (½, 1) SUPERSYMMETRY
Authors: PILOT CHRISTOPHER , RAJPOOT SUBHASH
Published: November 2004

We work out the spinor covariant derivative operators needed to construct left- and right-handed chiral superfields in a (1, ½) + (½, 1) supersymmetry. Also, we present a general method by which the completeness relation can be used to derive arbitrary identities for higher spin spinors, such as fermionic generators, coordinates, fields, etc.
θ VACUUM IN THE CHIRAL SCHWINGER MODEL
Authors: CARENA M. , WAGNER C.E.M.
Published: November 2004

The physical properties of the chiral Schwinger model are studied, for the particular value of the regularization-dependent parameter a=2. Within a gauge-invariant formulation, we prove that, apart from free physical chiral states, the chiral Schwinger model is equivalent to the vector Schwinger model. In particular, we show that, as in the vector theory, the cluster property is not fulfilled unless the vacuum state is properly defined.
DISCRIMINATION OF PHOTONS PRODUCED BY CLASSICAL AND QUANTUM-MECHANICAL SOURCES
Authors: LIPPERT THOMAS , VALLURI SREE RAM , GRÜN NORBERT , SCHEID WERNER
Published: November 2004

In this note we suggest an experimental proof for testing whether the photon production by bremsstrahlung in relativistic heavy ion collisions can be described in terms of a classical nuclear current density or not. We propose to measure not only the mean number of photons with a given energy, but also the corresponding root mean square deviation of it. A classical description of the current density is possible if the squared deviation is equal to the mean number of photons.
A MODEL OF MEMBRANE WITH FRACTIONAL SPIN AND UNUSUAL STATISTICS
Authors: YAHIKOZAWA SHIGEAKI
Published: November 2004

We present a model of membrane with fractional world-volume spin and exotic statistics. The model is constructed by coupling the bosonic membrane to the world-volume U(1) Chern-Simons term. Dirac’s method for the constrained system is used to quantize this theory and to show that the membrane has exotic statistics. We also evaluate finite size effects and clarify the relationship between a conserved charge in space-time and an angular-momentum operator on a world-volume.
SOLITON OPERATORS OF FRACTIONAL SPIN IN 2+1 DIMENSIONS
Authors: KARABALI DIMITRA
Published: November 2004

Soliton operators of fractional spin and statistics are constructed using canonical quantization of the O(3) nonlinear sigma model with a topological Hopf action in 2+1 dimensions. The role of the Hopf term as the nontrivial holonomy of a flat connection in the configuration space is emphasized.
GENERATIONS IN IRREDUCIBLE N=2 SUPERCONFORMAL COSET THEORIES
Authors: BAILIN DAVID , DUNBAR DAVID C. , LOVE ALEX
Published: November 2004

The massless states in 27 and [Formula: see text] of E6 are constructed for the ten N=2 superconformal coset theories based on a Hermitian symmetric space for which the gauge group is E6×E8 with no extra U(1) factors.
ON MANIFEST COVARIANCE CONDITION IN THE LAGRANGIAN FORMALISM
Authors: GRIGORE D.R.
Published: November 2004

The manifest covariance condition for a Poincaré covariant theory is analyzed in the framework of the Lagrangian formalism in a systematic way. We prove that this result is of a kinematic nature and also show that in some cases one needs an appropriate generalization of the Lagrangian formalism. Then the manifest covariance condition is analyzed in a Galilei invariant theory, obtaining the most general type of interaction allowed by this condition.
QUANTUM TODA THEORY AND THE CASIMIR ALGEBRA OF B2 AND C2
Authors: KAUSCH H.G. , WATTS G.M.T.
Published: November 2004

We consider W-algebras and their relation to quantum Toda field theory. We show that the chiral algebra is given as the commutant of the screening charges. The algebra WBC2, which is the Casimir algebra of B2 and C2, is then constructed using a free field representation. From this we are able to deduce the determinant in the Verma module and consequently some of the representation theory for the algebra.
TO SEARCH FOR THE EXOTIC TENSOR MESON IN THE ρ+ρ+ AND ρ−ρ− CHANNELS IN HADRON COLLISIONS AT INTERMEDIATE ENERGIES
Authors: ACHASOV N.N. , SHESTAKOV G.N.
Published: November 2004

It is shown that reactions with one-pion exchange, reactions of meson production in the central region and reactions of nucleon-antinucleon annihilation can be good laboratories to search, in the ρ+ρ+ and ρ−ρ−channels, for the exotic resonance states E++ and E−− with IG(JP)=2+(2+), the signs of the neutral partner of which were discovered probably in the reactions γγ→ρρ. Detailed estimates are presented for the cross sections of the reactions π+p→E++n→ρ+ρ+n, π−ρ→E−−Δ++→ρ−ρ−∆++, ρρ→n(E++)n→n(ρ+ρ+)n and similar ones at intermediate energies.
CANONICAL PHASES AND QUANTUM CONNECTION
Authors: KURATSUJI HIROSHI
Published: November 2004

The purpose of this paper is to give a somewhat expanded argument of the concept of the canonical phase recently investigated. This newly identified phase is considered to be a nonintegrable phase defined over the generalized phase space which is regarded as an integral realization of a “quantum (Hilbert) connection.” We formulate the theory in terms of the coherent state path integral. A particular interest is focused on the topological quantization in connection with the representation of compact Lie group and its application to the many-particle problem. We also examine the geometric characteristics of the canonical phase by using a spin model.
FINITE EUCLIDEAN MAGNETIC GROUP AND THETA FUNCTIONS
Authors: FUBINI S.
Published: November 2004

The Euclidean magnetic group of translations and rotations in a constant magnetic field is discussed in detail. The eigenfunctions of finite magnetic translations are shown to be related to the quasi periodic Jacobi theta functions, whose group theoretical properties under modular transformations are simply discussed. Invariance under finite rotations is very important; it leads to the two fundamental lattices of 60° and 90° already appearing in the theory of the phase transitions of Type II superconductors.
PROCESSES WITH LARGE IMPACT PARAMETERS AT COLLIDING BEAMS
Authors: KOTKIN G.L. , SERBO V.G. , SCHILLER A.
Published: November 2004

At the collider VEPP-4 a remarkable deviation of the measured bremsstrahlung photons from the standard calculation method has been measured in the reaction e+e−→e+e−γ. The decreasing number of photons is explained by the fact that large impact parameters give the essential contributions to the cross section. These parameters are by several orders of magnitude larger than the transverse beam sizes. In that case the standard definitions of “cross section” and “number of events” are invalid. Similar effects are expected for the single photon bremsstrahlung and the e+e− pair production at existing and planned high energy e±e−, ep and eγ colliders. A calculation scheme for particle production in the interaction of two bunches, which allows one to take into account these effects quantitatively, is presented. In this scheme the colliding bunches are represented as wave packets, and quantum distribution functions are used. The modified definitions of the cross section and the number of events contain the features of “nonlocality” and “interference”. Reasonable approximations which can be easily used are discussed. The results are applied to analyze the influence of the finite beam sizes on reactions which have been proposed for measuring the luminosity and the beam polarization at the colliders LEP and HERA.
ANALYSIS OF NONLEPTONIC KAON DECAYS USING CHIRAL-LOOP EXPANSION
Authors: BEL’KOV A.A. , EBERT D. , BOHM G. , SCHAALE A. , LANYOV A.V.
Published: November 2004

The amplitudes of the decays K→2π and K→3π have been calculated within the chiral Lagrangian approach including chiral loops. The phenomenological structure of the effective weak meson interaction has then been fixed by experimental data. We estimate the CP asymmetry for decay probabilities and slope parameters in K±→π±π±π∓ and K±→π0π0π± decays using data on Re(ε′/ε). The modification of the Li-Wolfenstein relation for the direct CP-violation parameter in [Formula: see text] decays is also discussed.
INTEGRABLE STRUCTURES OF UNITARY MATRIX MODELS
Authors: KHARCHEV S. , MIRONOV A.
Published: November 2004

The unitary matrix model is considered from the viewpoint of integrability. We demonstrate that this is an integrable system embedded into a two-dimensional Toda lattice hierarchy which corresponds to an integrable chain (modified Volterra) under a special reduction. The interrelations between this chain and other chains (like the Toda one) are demonstrated to be given by Bäcklund transformations. The case of the symmetric unitary model is discussed in detail and demonstrated to be connected with the Hermitian matrix model. This connection as a discrete analog of the correspondence between KdV and MKdV systems is investigated more thoroughly. We also demonstrate that unitary matrix models can be considered as two-component systems as well.
THE THEORY OF SCALE RELATIVITY
Authors: NOTTALE LAURENT
Published: November 2004

Basing our discussion on the relative character of all scales in nature and on the explicit dependence of physical laws on scale in quantum physics, we apply the principle of relativity to scale transformations. This principle, in combination with its breaking above the Einstein-de Broglie wavelength and time, leads to the demonstration of the existence of a universal, absolute and impassable scale in nature, which is invariant under dilatation. This lower limit to all lengths is identified with the Planck scale, which now plays for scale the same role as is played by light velocity for motion. We get new scale transformations of a Lorentzian form and generalize the de Broglie and Heisenberg relations. As a consequence the high energy length and mass scales now decouple, energy and momentum tending to infinity when resolution tends to the Planck scale, which thus plays the role of the previous zero point. This theory solves the problem of divergence of charge and mass (self-energy) in electrodynamics, implies that the four fundamental couplings (including gravitation) converge at the Planck energy, improves the agreement of GUT predictions with experimental results, and allows one to get precise estimates of the values of the fundamental coupling constants.
EQUIVALENCE OF THE QUADRATIC LAGRANGIANS FOR CHIRAL BOSONS
Authors: ABOUELSAOOD AHMED
Published: November 2004

Canonical quantization of both the Labastida-Pernici quadratic Lagrangian for two chiral bosons and the simplest chiral boson quadratic Lagrangian where the self-duality is imposed using a Lagrange-multiplier term is performed taking a proper account of the zero modes in the compact case, showing that they are exactly equivalent. The result is extended to the case of the bosonized chiral Schwinger model where no kinetic term for the gauge field is present, showing that a Wess-Zumino term does not affect the physics of the model.
DETERMINATION OF THE SINGULARITIES OF THE DYSON-SCHWINGER EQUATION FOR THE QUARK PROPAGATOR
Authors: MARIS P. , HOLTIES H.A.
Published: November 2004

In this paper we study the analytic continuation of the Dyson-Schwinger equation into the entire complex p2 plane. It is shown that in the usual ladder approximation with a running coupling, there are two complex-conjugate branch points and one real branch point in the timelike region. The real branch point corresponds presumably to a physical mass for a quark; but it is removed by the addition of a so-called confinement term to the bare gluon propagator: with this extra term, there are at least three pairs of complex-conjugate branch points. The origin of these complex singularities is not yet clear.
PHENOMENOLOGICAL PARAMETER ANALYSIS OF A HIGGSLESS ELECTROWEAK GAUGE THEORY WITH INDUCED INTERACTIONS INCLUDED
Authors: BÖNISCH R. , KÖGERLER R.
Published: November 2004

The nonlinear version of the electroweak gauge theory (BESS model) is considered. It contains no physical Higgs particle but, instead, a further triplet of massive gauge bosons. Parameter bounds are derived which can be deduced from expected data of high precision experiments. The induced fermionic couplings which emerge due to the model’s nonrenormalizability are treated in a consistent way.
ANYON EQUATION ON A TORUS
Authors: HO CHOON-LIN , HOSOTANI YUTAKA
Published: November 2004

Starting from the quantum field theory of nonrelativistic matter on a torus interacting with Chern-Simons gauge fields, we derive the Schrödinger equation for an anyon system. The nonintegrable phases of the Wilson line integrals on a torus play an essential role. In addition to generating degenerate vacua, they enter in the definition of a many-body Schrödinger wave function in quantum mechanics, which can be defined as a regular function of the coordinates of anyons. It obeys a non-Abelian representation of the braid group algebra, being related to Einarsson’s wave function by a singular gauge transformation.
U(∞) GAUGE THEORY FROM HIGHER DIMENSIONS
Authors: SHIRAISHI KIYOSHI
Published: November 2004

We show that classical U (∞) gauge theories can be obtained from the dimensional reduction of a certain class of higher-derivative theories. In general, the exact symmetry is attained in the limit of degenerate metric; otherwise, the infinite-dimensional symmetry can be taken as spontaneously broken. Monopole solutions are examined in the model for scalar and gauge fields. An extension to gravity is also discussed.
DOES DUALITY SURVIVE BACKGROUND FIELDS?
Authors: GOVAERTS JAN
Published: November 2004

Target space duality is shown to break down for generic space-time background fields, in a certain class of exact solutions to the string equations.
ON THE SEMI-CLASSICAL APPROXIMATION TO THE SUPERSTRING THEORY
Authors: POLLOCK M.D.
Published: November 2004

The semi-classical limit of the compactified, heterotic superstring theory is examined, including the effects of higher-derivative terms [Formula: see text] in the effective Lagrangian. The total wave-function Ψ obeys a Schrödinger equation in the mini-superspace ds2=dt2−e2α(t)dx2, the canonical coordinates being the position α and the velocity (Hubble parameter) [Formula: see text], while the cosmic time coincides with the parameter introduced by Tomonaga, ∂/∂σ≡∂/∂t≡ξ∂/∂α. The wave function describing the matter, Ψ m , also obeys a linear Schrödinger equation. The relevance of this result to the problem of non-locality in quantum mechanics is discussed.
SPINOR OPERATORS
Authors: LA JARA F. J. DE , TABENSKY R. R.
Published: November 2004

We define and study spinor operators for finite dimensional representations of the Lorentz group. The family of all such operators is given. Grassmann variables appear as one of their simplest realizations. Besides we establish a relation between spinor operators and four-vector operators, which simplifies greatly the theory of vector operators.
TWO-STAGE ORBIFOLD COMPACTIFICATIONS OF HETEROTIC STRINGS
Authors: MOSS S.A.
Published: November 2004

Orbifold compactifications of ten-dimensional heterotic strings in a two-dimensional and a four-dimensional stage” are discussed. A classification of symmetry breaking for a class of two-stage Z3×Z3 and Z2×Z3 compactifications is made. The general structure of such models is considered, and an example spectrum calculated.
EXTENDED INFLATION WITH NONMINIMALLY COUPLED INFLATON FIELD
Authors: PANCHAPAKESAN N. , SETHI SHIV K.
Published: November 2004

An extended inflation model, in which the inflaton field is nonminimally coupled to the gravity, is discussed. It is shown that the nucleation rate of bubbles, during a phase transition in the inflaton field, can increase as the transition proceeds for a wide range of parameters of the inflaton potential. The bounce action for three possible cases—the strong gravity regime, the thick-walled Coleman-De Luccia bubbles and the thin-walled bubbles—is evaluated. The resulting bubble distribution for all the cases is shown to be in conformity with cosmological constraints for ω<500.
ON THE ROTATING SOLITON IN THE CHIRAL MODEL
Authors: OKAZAKI TAKASHI , FUJII KANJI , OGAWA NAOHISA
Published: November 2004

We study the quantum rotating soliton in the nonlinear σ model which is obtained by minimizing the total energies of rotating soliton. Existence of such a soliton is expected from the Derrick’s theorem even when the Skyrme term is absent because the rotational energy prevents the soliton from collapsing. The asymptotic behavior of the profile function is shown to be determined by the physical pion mass which appears in the PCAC relation in the nonlinear σ model. The energies of spin-1/2 and − 3/2 solitons are obtained numerically with the use of a simple trial function.
NONPERTURBATIVE BEHAVIOR IN THREE-DIMENSIONAL QED
Authors: WAITES A.B. , DELBOURGO R.
Published: November 2004

Infrared singularities in QED3 can be avoided by including at least one massless source which couples to the photon. Once that is arranged it is possible to obtain nonzeromass solutions for the source Green functions in scalar and (doubled) spinor electrodynamics, by using the gauge technique. We find that the asymptotic results for the source spectral ρ functions are typically ρ(p)≃(p2−m2)−1−e2/cπ2 as p→m, and ρ(p)≃p−2 exp (c′e2/πp) as p→∞. The constants c and c′ are respectively related to the number of charged massless particles and their “spin” character.
NEW SUPERCONFORMAL CONSTRUCTIONS ON TRIANGLE-FREE GRAPHS
Authors: HALPERN M.B. , OBERS N.A.
Published: November 2004

It is known that the superconformal master equation has an ansatz which contains a graph theory of superconformal constructions. In this paper, we study a subansatz which is consistent and solvable on the set of triangle-free graphs. The resulting super-conformal level-families have rational central charge and the constructions are generically unitary. The level-families are generically new because irrational conformal weights occur in the generic construction, and the central charge of the generic level-family cannot be obtained by coset construction. The standard rational superconformal constructions in the subansatz are a subset of the constructions on edge-regular triangle-free graphs, and we call attention to the nonstandard constructions on these graphs as candidates for new rational superconformal field theories. We also find superconformal quadratic deformations at particular levels on almost all edge-regular triangle-free graphs.
TWO-DIMENSIONAL GRAVITY FROM d=0 AND d=1 MATRIX MODELS
Authors: SILVESTROV P.G.
Published: November 2004

The two nonperturbative formulations of 2d gravity are compared. The first one is an analytical continuation of the matrix integral. This method provides a simple description of random surfaces statistics, but leads to complex expectation values. In the second method, proposed by Marinari and Parisi, observables in 2d gravity are identified with the correlators for 1d supersymmetric string. The correct quantization in the double scaling limit reduces the problem to the calculation of a few eigenfunctions of simple one-dimensional Hamiltonian. We propose a function which may substitute the Painleve transcendent for the second definition of 2d gravity. The universality of the model is also discussed.
LOOP EQUATIONS AND THE TOPOLOGICAL PHASE OF MULTI-CUT MATRIX MODELS
Authors: CRNKOVIĆ Č. , DOUGLAS M. , MOORE G.
Published: November 2004

We study the double scaling limit of mKdV type, realized in the two-cut Hermitian matrix model. Building on the work of Periwal and Shevitz and of Nappi, we find an exact solution including all odd scaling operators, in terms of a hierarchy of flows of 2×2 matrices. We derive from it loop equations which can be expressed as Virasoro constraints on the partition function. We discover a “pure topological” phase of the theory in which all correlation functions are determined by recursion relations. We also examine macroscopic loop amplitudes, which suggest a relation to 2D gravity coupled to dense polymers.
PATH INTEGRAL CALCULATION OF GREEN’S FUNCTION FOR SCHRÖDINGER EQUATION IN UNITARY GAUGE
Authors: ROZANSKY L.
Published: November 2004

Green’s function of Schrödinger equation is represented as a time-reparametrization invariant path integral. Unitary gauge fixing enables us to get the WKB preexponential factor without calculating determinants of operators containing derivatives.
NEW N=1 EXTENDED SUPERCONFORMAL ALGEBRAS WITH TWO AND THREE GENERATORS
Authors: BLUMENHAGEN R. , EHOLZER W. , HONECKER A. , HÜBEL R.
Published: November 2004

In this paper we consider extensions of the super Virasoro algebra by one and two super primary fields. Using a nonexplicitly covariant approach we compute all SW algebras with one generator of dimension up to 7 in addition to the super Virasoro field. In complete analogy to W algebras with two generators, most results can be classified using the representation theory of the super Virasoro algebra. Furthermore, we find that the [Formula: see text] algebra can be realized as a subalgebra of [Formula: see text] at [Formula: see text]. We also construct some new SW algebras with three generators, namely [Formula: see text], [Formula: see text] and [Formula: see text].
MEAN STAGGERED POLARIZATION FOR THE HIGHER SPIN ANALOG OF THE 6-VERTEX MODEL
Authors: DATE ETSURO , JIMBO MICHIO , MIKI KEI , OKADO MASATO
Published: November 2004

We compute the mean staggered polarization of the vertex models corresponding to higher spin representations of [Formula: see text]. This generalizes a result of Baxter for spin 1/2.
UNITARY BRAID REPRESENTATIONS
Authors: WENZL HANS
Published: November 2004

The original motivation for studying unitarizable representations of the braid group was to construct interesting examples of subfactors of II1 von Neumann factors. This is possible for representations factoring through Hecke algebras or q-Brauer algebras only if the deformation parameter is a root of unity. Information gained from this work can be applied to studying tensor products of representations of quantum groups at roots of unity and invariants of 3-manifolds.
HETEROSTRUCTURAL FLUCTUATIONS IN SUPERCONDUCTORS
Authors: YUKALOV V. I.
Published: November 2004

Superconductors are considered in which there occur fluctuations of one crystallographic structure inside another. The role of these heterostructural fluctuations on superconducting properties are analysed. The occurrence of these fluctuations explains anomalous saggings of Mössbauer factor at phase transition in high-temperature superconductors.
THE MICROSCOPIC THEORY OF THE SURFACE PROPERTIES OF ANHARMONIC CRYSTALS II: The (110) and (111) Surface of BCC Crystal
Authors: ZUBOV V. I. , MAMONTOV I. V.
Published: November 2004

The correlative unsymmetrized self-consistent field method developed in preceding works is used to study the structural, dynamical, and thermodynamic properties of the (110) and (111) faces of the anharmonic BCC crystal. The character of the lattice relaxation near the (110) surface is similar to that near the (001) face investigated in Part I. There is strong anisotropy in the atomic vibrations near the (110) surface and in its thermodynamic functions. Near the (111) face the lattice relaxation decreases gradually, with oscillations occurring in the interplanar distances. It should be emphasized that such results are obtained when the nearest-neighbour interactions are taken into account. Unlike the (001) face, the surface tensions of the faces considered are negative. The effect of the long-range interactions are studied.

In the preceding papers1–7 the correlative unsymmetrized self-consistent field method (CUSF) has been developed to investigate the structural, dynamical, and thermodynamic surface properties of anharharmonic crystals. In the first part of this work7 (to be referred to as I), the (001) faces of BCC crystals have been studied taking into account the nearest-neighbour interactions. Here we shall calculate the properties of other singular surfaces of such crystals.
TWO-POINT GREEN FUNCTION OF CHERN–SIMONS GAUGE FIELD IN ANYON GAS
Authors: HIEU NGUYEN VAN , SON NGUYEN HUNG
Published: November 2004

The quantum theory of the anyon gas was developed in the framework of the field theoretical formalism. The existence of the classical background CS gauge field created by the quasiparticles below the Fermi level and acting as some effective magnetic field was taken into account. The expressions of the two-point Green functions of the free and interacting CS gauge fields were derived. It was shown that they determine the conductivity tensor of the anyon gas. The relevance to the FQHE was discussed.
LANDAU THEORY OF THE NEMATIC-ISOTROPIC PHASE TRANSITION
Authors: STEPANESCU A. , MIRALDI E.
Published: November 2004

The influence of the surface properties and the sample thickness on the critical temperature of the nematic-isotropic phase transition is theoretically analyzed. By using the Landau expression for the free-energy density it is shown that the sample thickness can strongly influence the phase transition.

In particular our analysis demonstrates that it is possible to define a typical length connected with the surface properties of the substrate and with the elastic properties of the nematic material. When this length is much smaller than the sample thickness the ideal situation of homogeneous sample holds.

On the other hand if this characteristic surface length is of the order of the sample thickness some peculiar surface length behaviour in the phase transition appears.
OPEN PROBLEMS IN HEAVY-ELECTRON SYSTEMS
Authors: Ott H.R.
Published: November 2004

Some of the outstanding and newly discovered features of heavy-electron systems are reviewed. Unconventional superconductivity, small-moment ordering, and possible non-Fermi-liquid behaviour are the most intriguing properties that deserve further experimental and theoretical studies because they touch upon important questions related with strong many-body effects in general. Possible ground states of these systems are strongly influenced by small variations of chemical composition or by mere lattice defects.
ORBITAL KONDO EFFECT DUE TO ASSISTED HOPPING: SUPERCONDUCTIVITY, MASS ENHANCEMENT IN COOPER OXIDES WITH APICAL OXYGEN
Authors: ZAWADOWSKI A. , PENC K. , ZIMANYI G.T.
Published: November 2004

Orbital Kondo effect is treated in a model, where additional to the conduction band there are localized orbitals with energy not very far from the Fermi energy. If the hopping between the conduction band and the localized heavy orbitals depends on the occupation of the conduction band orbital then orbital Kondo correlation occurs. The assisted hopping vertex is enhanced due to the Coulomb interaction between the heavy orbital and the conduction band. The enhanced hopping results in mass enhancement and attractive interaction in the conduction band. The superconductivity transition temperature is calculated. The models of this type can be applied to the high- Tc superconductors where the non-bonding oxygen orbitals of the apical oxygens play the role of heavy orbitals. For an essential range of the parameters the Tc obtained is about 100K.
High Frequency Conductivity in the Fractional Quantum Hall Regime
Authors: Willett R.L. , Paalanen M.A. , Pfeiffer L.N. , West K.W. , Ruel R.R.
Published: November 2004

Surface acoustic wave (SAW) propagation on high quality AlGaAs/GaAs heterostructures is examined in the fractional quantum Hall regime By measuring the transmitted SAW amplitude and frequency the 2D electron system (2DES) conductivity at the SAW frequency can be deduced and compared to the measured d.c. conductivity. Up to about 500MHz the SAW derived conductivity does not differ substantially from the measured d.c. conductivity. At higher frequencies some deviations are observed at FQHE and IQHE states However, at Landau level filling ν=1/2 SAW propagation is markedly different from that observed in the neighboring filling factor range; the response to the SAW is the opposite of that suggested by the d.c. conductivity In addition, anomalous sound propagation is also observed in the small filling factor range ν≲1/5, where electron solid formation is suspected. The properties of these distinct SAW anomalies are described and their possible origins discussed.
UNIVERSALITY IN DISORDERED MESOSCOPIC SYSTEMS
Authors: COHEN A. , SHAPIRO B.
Published: November 2004

We consider an ensemble of disordered electronic samples at the mobility edge (at zero temperature) and study the conductance distribution PL(g), for samples of size L. We derive an equation for the cumulant generating function and find its solution, for any initial distribution P0(g). We prove that, independent of P0(g), the distribution PL(g) approaches an entirely universal function P*(g) when L→∞.
ON PERIODIC REPRESENTATIONS OF QUANTUM GROUPS
Authors: ARNAUDON DANIEL
Published: November 2004

We present some results on representations of quantum groups at the root of unity. In the case of SL(2)q, the classification of the finite dimensional irreducible representations is given. For [Formula: see text] with [Formula: see text] a semi-simple or affine Lie algebra and q an mth root of unity (m odd), we classify the representations of dimension [Formula: see text] on which the actions of the Chevalley generators are injective. Finally, we adapt the Gelfand-Zetlin basis to the case of SL(N)q and IU(N)q.
NON-BORN CALCULATION OF ZERO TEMPERATURE CONDUCTIVITY OF A DOPED SEMICONDUCTOR UNDER VARIOUS SCREENING MODELS
Authors: TAKESHIMA MASUMI
Published: November 2004

The zero temperature conductivity of a doped semiconductor is calculated by numerically solving the integral equation which is given as a formal solution of the impurity scattering problem. Here the free-carrier screening of the impurity potential is also discussed, giving a tentative model of the screening. Then the critical exponent for the relation between conductivity and carrier concentration is found to be 0.8 for uncompensated Si:P. The critical carrier concentration for the metal-insulator transition is also calculated for the model of Mott localization as compared with that of Anderson localization, showing largely different results.
FAR INFRARED REFLECTIVITY STUDY OF CERAMIC SUPERCONDUCTORS
Authors: MEMON A. , KHAN M.N. , AL-DALLAL S. , TANNER D.B. , PORTER C.D.
Published: November 2004

We report on a study of the far-infrared reflectivity of mixed rare earths and lanthanides ceramic superconductors RBa 2 Cu 3 O 7 in the normal state. Our results show that the strength of the phonon modes is reduced when yittrium is partially replaced by gadolinium and europium. Also the critical temperature of these mixed materials is reduced as indicated by the four probe technique.
THERMODYNAMICS OF THE FERMI-LINEARIZED EXTENDED HUBBARD MODEL
Authors: DANANI ANDREA , MONTORSI ARIANNA , RASETTI MARIO
Published: November 2004

The fermi linearization scheme for a two-site cluster (dimer) is applied to the extended Hubbard model, including Coulomb interaction between nearest neighbour sites. The partition function and the order parameter, as well as the average double-occupation and local magnetic moment are evaluated. The theory is checked by extended numerical analysis, performed here in the homogeneous case, when pairing is zero, and deriving the explicit temperature and filling dependence of the above quantities. An interesting feature that emerges from such calculations is that the mean-field parameter characteristic of fermi-linearization is capable of describing two different phases, one of which is not present in the conventional Hubbard model. The order parameters corresponding to the two phases are explicitly derived. The novel phase can be ascribed to the n.n. Coulomb interaction, the role of whose strength V is analysed.
SPECTROSCOPY OF SIZE-SELECTED SEMICONDUCTOR CLUSTERS: BULK LIKE SPECTRA SEEN IN “MOLECULAR SIZE” CLUSTERS
Authors: Mandich M.L.
Published: November 2004

Absorption spectra have been obtained for size selected, gas phase neutral semiconductor clusters using resonant one- and two-color photodissociation spectroscopy. We now have spectra for indium phosphide clusters containing up to 14 atoms and for silicon clusters containing up to 70 atoms. These spectra show unexpected similarities between the optical signatures of minute semiconductor clusters and their corresponding bulk forms. Equally unexpected is the spectral regularity that we observe with size for silicon clusters, which challenges all existing theories about their geometric and electronic structures.
Superconducting and Normal State Properties of the A3C60 Compounds
Authors: Holczer Károly
Published: November 2004

The A 3 C 60 compounds, where A=alkali atom, form fcc -lattices (cryolite structure) and are highly ionic [ A +]3·[ C 60]3−. The C 60 icosahedra are located in sites of local cubic symmetry thereby preserving the degeneracy of the t 1u orbitals, allowing for the formation of a narrow half filled band of a width comparable to or smaller than the various molecular excitation energies. The T c - s of the dozen or so compounds already synthesized span the range from 2–33 K; the variation of T c with pressure and from material to material suggests that the attraction responsible for the Cooper pair formation is a local property of the C 60 molecules, so that variations of the density-of-state ρ(ε F ) at the Fermi level (i.e. bandwidth) determine T c . The values of the superconducting parameters, λ L and ξ o , determined from critical field and µSR measurements, favor a local pairing picture, but are at best only marginally supportive for the expected density-ofstate variations. The so far available 13 C nuclear relaxation, susceptibility and ESR measurements in the normal state manifest several features that are more related to the complex correlated nature of the C 60 molecules than to the freeelectron band effects of the simple lattice they are arranged in.
DIFFUSION IN METALS AND ALLOYS UNDER IRRADIATION
Authors: Naundorf Volkmar
Published: November 2004

Experimental investigations of the diffusion in crystalline metals and alloys under irradiation are reviewed emphasizing those experiments, in which atom transport was directly observed. Three types of results will be considered: (i) radiation-enhanced self- and impurity diffusion, (ii) segregation of components in homogeneous alloys, and (iii) the behaviour of thermodynamically (meta-) stable precipitates under the simultaneous action of radiation-enhanced diffusion and atomic mixing. The analysis of the experiments will be based on well known defect kinetics, using as fundamental parameters the fraction of freely migrating defects, the effective sink concentration for point defect annihilation, and the mixing efficiency.
POSSIBLE DOPING MECHANISM IN a-Si:H—THE IMPURITY-DEFECT COMPLEX MODEL
Authors: FONG C.Y. , YANG L.H.
Published: November 2004

The present status of understanding the doping mechanism in hydrogenated amorphous silicon was reviewed. In particular, we focused on a possible final state of the doping process — the impurity-defect complex. Both theoretical and experimental evidences favor the formation of the impurity-defect complex. However, the microscopic process of forming this final state is still controversial.
STRUCTURAL AND DYNAMICAL PROPERTIES OF BRANCHED POLYMERS AND GELS AND THEIR RELATION WITH ELASTIC PERCOLATION NETWORKS
Authors: SAHIMI MUHAMMAD
Published: November 2004

Experimental data for structural and dynamical properties of branched polymers and gels near the sol-gel transition, such as the viscosity, elastic moduli, the distribution of relaxation times, and the fractal dimension are reviewed and discussed. The percolation model of gelation is described, and two vector variants of it for calculating the viscosity and elastic moduli of (physical and chemical) gels, namely, the superelastic and elastic percolation networks are introduced and their scaling properties near the percolation threshold are discussed. It is argued that such networks provide theoretically-consistent explanations for the experimental data for static and dynamic properties of polymers near the sol-gel transition. These models are also contrasted with the scalar percolation models for predicting the same properties of gel polymers.