March 1997 arXiv papers — page 4

David N. Schramm, Michael S. Turner

Four light isotopes - D, ^3He, ^4He and ^7Li - were produced by nuclear reactions a few seconds after the big bang. New measurements of ^3He in the ISM by Gloeckler and Geiss and of deuterium in high redshift hydrogen clouds by Tytler and his collaborators provide further confirmation of big-bang nucleosynthesis and new insight about the density of ordinary

K. Iwasawa, A. C. Fabian, G. Matt

We report a new analysis of ASCA data on the iron K line complex in NGC1068. The line complex basically consists of three components, as previously reported. A weak red wing of the 6.4 keV fluoresence iron K line is found. A plausible explanation is Compton scattering in optically thick, cold matter which can be identified with an obscuring torus or cold gas

Tomoya Ogawa, Boudewijn F. Roukema, Kazuyuki Yamashita

During the epoch of galaxy formation, the formation of the first galaxies in regions of high overdensity may lead to an initial amplitude of the spatial correlation function of galaxies, $ξ_0,$ much higher than that expected in linear perturbation theory. This initially high ``bias'' would consequently decrease to the near-unityvalues expected from l

M. D'Onofrio, M. Capaccioli, S. Zaggia, N. Caon

We derive the relative distances to the Virgo, Fornax, and Coma clusters of galaxies by applying the Dn-sigma and the Fundamental Plane (FP) relations to the data of the homogeneous samples of early--type galaxies studied by Caon etal, Lucey etal, and Jorgensen etal. The two distance indicators give consistent results, the relative distance moduli to Fornax

R. Shankar

Some personal reminiscences are followed by a brief illustration of how effective field theories are used in condensed matter physics. Examples include Landau's Fermi liquid, sigma models with topological terms, Dirac fermions and the Gross Neveu model.

Michael Bershadsky, Cumrun Vafa

We show the existence of global gauge anomalies in six dimensions for gauge groups SU(2),SU(3) and G_2 coupled to matter, characterized by an element of Z_{12},Z_6 and Z_3 respectively. Consideration of this anomaly rules out some of the recently proposed 6 dimensional N=1 QFT's which were conjectured to possess IR fixed point at infinite coupling. We ge

Torben Hannah

The inverse amplitude method has previously been successfully applied to $ππ$ scattering in order to extend the range of applicability of chiral perturbation theory. However, in order to take the chiral zeros into account systematically, the previous derivation of the inverse amplitude method has to be modified. It is shown how this can be done to both one a

Kristof Petrovay

In recent years, our knowledge of photospheric magnetic fields went through a thorough transformation--nearly unnoticed by dynamo theorists. It is now practically certain that the overwhelming majority of the unsigned magnetic flux crossing the solar surface is in turbulent form (intranetwork and hidden fields). Furthermore, there are now observational indic

K. Petrovay, F. Moreno-Insertis

Results from a numerical and analytical investigation of the solution of a nonlinear axially symmetric diffusion equation for the magnetic field are presented for the case when the nonlinear dependence of the diffusivity nu(B) on the magnetic field satisfies basic physical requirements. We find that for sufficiently strong nonlinearity (i.e. for sufficiently

G. M. Bruun, V. N. Nicopoulos

We have examined the validity of the Gor'kov expansion in the strength of the order parameter of type II superconductors near the upper critical field. Although the degeneracy of the electron levels in a magnetic field gives non- perturbative terms in the solution to the Bogoliubov-de Gennes equations we find, contrary to recent claims, that these non-pe

S. F. Hassan, Spenta R. Wadia

We address the derivation of the effective conformal field theory description of the 5-dimensional black hole, modelled by a collection of D1- and D5- branes, from the corresponding low energy U(Q_1)xU(Q_5) gauge theory. Finite horizon size at weak coupling requires both Q_1 and Q_5 to be large. We derive the result in the moduli space approximation (say for

Lior M. Burko, Amos Ori

We study numerically the fully nonlinear gravitational collapse of a self-gravitating, minimally-coupled, massless scalar field in spherical symmetry. Our numerical code is based on double-null coordinates and on free evolution of the metric functions: The evolution equations are integrated numerically, whereas the constraint equations are only monitored. Th

H. Niggemann, G. Uimin, J. Zittartz

We consider a mechanism for competing interactions in alternating Heisenberg spin chains due to the formation of local spin-singlet pairs. The competition of spin-1 and spin-0 states reveals hidden Ising symmetry of such alternating chains.

P. Nalbach, O. Terzidis

Substitutional defects in a cubic symmetry (such as a lithium defect in a KCl host crystal) can be modeled appropriately by an eight-state-system. Usually this tunneling degree of freedom is approximated by a two-level-system. We investigate the observable differences between the two models in three contexts. First we show that the two models predict differe

Khaled Abdel-Khalek

We discuss how to represent the non-associative octonionic structure in terms of the associative matrix algebra using the left and right octonionic operators. As an example we construct explicitly some Lie and Super Lie algebra. Then we discuss the notion of octonionic Grassmann numbers and explain its possible application for giving a superspace formulation

Claudio S. Shida, Vera B. Henriques

We compare equilibrium probability distributions obtained from Monte Carlo simulations for different spin exchange dynamics with the exact Boltzmann distribution for the fixed magnetization Ising model on small lattices. We present simple arguments and numerical evidence in order to show that "efficient" Kawasaki exchange does not lead to Boltzmann e

N. N. Achasov, A. A. Kozhevnikov

The analysis of the vector isoscalar excitations in the energy range between 1 and 2 GeV of the $e^+e^-$ annihilation is presented for the final states $π^+π^-π^0$, $ωπ^+π^-$, $K^+K^-$, $K^0_SK^\pmπ^\mp$ and $K^{\ast0}K^-π^++ c.c$. The effects of both the resonance mixing and the successive opening of multiparticle channels, with the energy dependent partial

Steven Brandt, Bernd Bruegmann

We consider the initial data problem for several black holes in vacuum with arbitrary momenta and spins on a three space with punctures. We compactify the internal asymptotically flat regions to obtain a computational domain without inner boundaries. When treated numerically, this leads to a significant simplification over the conventional approach which is

Shun'ya Mizoguchi

We consider dimensional reduction of the eleven-dimensional supergravity to less than four dimensions. The three-dimensional $E_{8(+8)}/SO(16)$ nonlinear sigma model is derived by direct dimensional reduction from eleven dimensions. In two dimensions we explicitly check that the Matzner-Misner-type $SL(2,R)$ symmetry, together with the $E_8$, satisfies the g

N. V. Prokof'ev, B. V. Svistunov, I. S. Tupitsyn

We show how the worldline quantum Monte Carlo procedure, which usually relies on an artificial time discretization, can be formulated directly in continuous time, rendering the scheme exact. For an arbitrary system with discrete Hilbert space, none of the configuration update procedures contain small parameters. We find that the most effective update strateg

Sang Pyo Kim, Jeong-Young Ji, Hak-Soo Shin, Kwang-Sup Soh

Using the coherent-state representation we show that the classical Einstein equation for the FRW cosmological model with a general minimal scalar field can be derived from the semiclassical quantum Einstein equation.

E. Atzmon

We show that the probabilistic distribution over the space in the spectator world, can be associated via noncommutative geometry (with some modifications) to a metric in which the particle lives. According to this geometrical view, the metric in the particle world is ``contracted'' or ``stretched'' in an inverse proportion to the probability

N. P. Proukakis, K. Burnett, H. T. C. Stoof

In this paper we use microscopic arguments to derive a nonlinear Schrödinger equation for trapped Bose-condensed gases. This is made possible by considering the equations of motion of various anomalous averages. The resulting equation explicitly includes the effect of repeated binary interactions (in particular ladders) between the atoms. Moreover, under the

Chistopher A. Fuchs

I demonstrate that, rather unexpectedly, there exist noisy quantum channels for which the optimal classical information transmission rate is achieved only by signaling alphabets consisting of nonorthogonal quantum states.

H. Gumral

Three dimensional unsteady flow of fluids in the Lagrangian description is considered as an autonomous dynamical system in four dimensions. The condition for the existence of a symplectic structure on the extended space is the frozen field equations of the Eulerian description of motion. Integral invariants of symplectic flow are related to conservation laws

V. Buzek, S. L. Braunstein, M. Hillery, D. Bruss

We present a network consisting of quantum gates which produces two imperfect copies of an arbitrary qubit. The quality of the copies does not depend on the input qubit. We also show that for a restricted class of inputs it is possible to use a very similar network to produce three copies instead of two. For qubits in this class, the copy quality is again in

Lin Zhang, Ian Fuss

This paper presents a set of quantum Reed-Muller codes which are typically 100 times more effective than existing quantum Reed-Muller codes.

P. Akueson, D. Gurevich

We consider nonquasiclassical solutions to the quantum Yang-Baxter equation and the corresponding quantum cogroups $\Fun(SL(S))$ constructed earlier by one of the authors . We give a criterion of the existence of a dual quasitriangular structure in the algebra $\Fun(SL(S))$ and describe a large class of such objects related to the Temperley-Lieb algebra sati

A. T. Kruppa, P. -H. Heenen, H. Flocard, R. J. Liotta

Ground state energies and decay widths of particle unstable nuclei are calculated within the Hartree-Fock approximation by performing a complex scaling of the many-body Hamiltonian. Through this transformation, the wave functions of the resonant states become square integrable. The method is implemented with Skyrme effective interactions. Several Skyrme para

K. S. Sarkaria

Consider partitions, of a cardinality $(q-1)(d+1)+1$ generic subset of euclidean $d$-space, into $q$ parts whose convex hulls have a nonempty intersection. We show that if these partitions are counted with appropriate signs $\pm 1$ then the answer is always $((q-1)!)^d$. Also some other related results are given.

Edward Witten

N=2 supersymmetric gauge theories in four dimensions are studied by formulating them as the quantum field theories derived from configurations of fourbranes, fivebranes, and sixbranes in Type IIA superstrings, and then reinterpreting those configurations in M theory. This approach leads to explicit solutions for the Coulomb branch of a large family of four-d

F. T. Brandt, J. Frenkel

We extend to a general class of covariant gauges an approach which relates the thermal Green functions to forward scattering amplitudes of thermal particles. A brief discussion of the non-transversality of the thermal gluon polarization tensor is given in this context. This method is then applied to the calculation of the ln(T) contributions associated with

Roberto Casadio, Benjamin Harms

We generalize a family of Lagrangians with values in the Poincaré group ISO(d-1,1), which contain the description of spinning strings in flat (d-1)+1 dimensions, by including symmetric terms in the world-sheet coordinates. Then, by promoting a subgroup H=R^n, n less than or equal to d, which acts invariantly from the left on the element of ISO(d-1,1), to a g

S. Balaska, J. Maeder, W. Ruehl

The critical points of the continuous series are characterized by two complex numbers l_1,l_2 (Re(l_1,l_2)< 0), and a natural number n (n>=3) which enters the string susceptibility constant through gamma = -2/(n-1). The critical potentials are analytic functions with a convergence radius depending on l_1 or l_2. We use the orthogonal polynomial method and so

Witold Skiba

We review mechanisms of dynamical supersymmetry breaking. Several observations that narrow the search for possible models of dynamical supersymmetry breaking are summarized. These observations include the necessary and sufficient conditions for supersymmetry breaking. The two conditions are based on non-rigorous arguments, and we show examples where they are

G. M. Gandenberger

Using U_q(a_n^(1))- and U_q(a_2n^(2))-invariant R-matrices we construct exact S-matrices in two-dimensional space-time. These are conjectured to describe the scattering of solitons in affine Toda field theories. In order to find the spectrum of soliton bound states we examine the pole structure of these S-matrices in detail. We also construct the S-matrices

V. S. Fadin, V. A. Khoze, A. D. Martin

The study of an intermediate mass Higgs boson, via the process gamma-gamma -> H -> bbbar from an initiallypolarized J_z = 0 state, has been advocated as an important feasible goal of a future photon linear collider. The crucial argument was the m_b^2/s suppression of the background process gamma-gamma (J_z = 0) -> bbbar. We critically review the contribution

Michael Dittmar, Herbi Dreiner

We show that the Standard Model Higgs decay $h^0 \to W^+W ^- \to l^+ l^- ν{\barν}$ is the most sensitive mode for SM Higgs searches in the range 155-180 GeV. The previously considered mode $h^0 \to Z^0 Z^{0*} \to l^+ l^- l^+l^-$ has a significantly lower search sensitivity. We place particular emphasis on two new cuts based on (i) the boost and (ii) the spin

Michael I. Eides, Howard Grotch

A new approach to calculation of the binding corrections to the magnetic moments of the constituents in a loosely bound system, based on the Bargmann-Michel-Telegdi equation, is suggested. Binding corrections are calculated in this framework, and the results confirm earlier calculations performed by other methods. Our method clearly demonstrates independence

L. Frankfurt, W. Koepf, J. Mutzbauer, G. Piller

We discuss the coherent photo- and leptoproduction of vector mesons from deuterium at intermediate (virtual) photon energies, 3 GeV < nu < 30 GeV. These processes provide several options to explore the space-time evolution of small size quark-gluon configurations. Furthermore, we study the dependence of the production cross section on the energy and momentum

F. Lenz, M. Thies

A study of QCD at finite extension is presented and the relation to QCD at finite temperature and in the infinite momentum frame is discussed. The dynamics of Polyakov loops is investigated and shown to be described by functional integrals with finite range of integration. Consequences of this non-Gaussian form of the generating functional concerning the QCD

01 Collaboration

The anomalous behavior of 2-dimensional factorial moment in nucleus-nucleus collisions is studied in some detail using both mini-bias and central collision data of ^{16}O-, ^{32}S- and ^{197}Au-Em interactions from EMU01 experiment. The correct value for the effective Hurst exponent in the analysis of higher-dimensional factorial moment is found to be greate

Fuguang Cao, J. Cao, T. Huang, B. Q. Ma

For obtaining the spin space wave function of the pion meson in the light-cone formalism from the naive quark model, it is necessary to take into account Wigner rotation. Consequently there are higher helicity ($λ_1+λ_2=\pm 1$) components in the light-cone spin space wave function of the pion besides the usual helicity ($λ_1+λ_2=0$) components. For the pion

Adrian Patrascioiu, Erhard Seiler

According to the standard classification of Conformal Quantum Field Theory (CQFT) in two dimensions, the massless continuum limit of the $O(2)$ model at the Kosterlitz-Thouless (KT) transition point should be given by the massless free scalar field; in particular the Noether current of the model should be proportional to (the dual of) the gradient of the mas

Adrian Patrascioiu, Erhard Seiler

It is generally taken for granted that two-dimensional critical phenomena can be fully classified by the well known two-dimensional (rational) conformal quantum field theories (CQFTs). In particular it is believed that in models with a continuous symmetry characterized by a Lie group $G$ the continuum theory enjoys an enhanced symmetry $G\times G$ due to the

Curt Cutler

We calculate the angular resolution of the planned LISA detector, a space-based laser interferometer for measuring low-frequency gravitational waves from galactic and extragalactic sources. LISA is not a pointed instrument; it is an all-sky monitor with a quadrupolar beam pattern. LISA will measure simultaneously both polarization components of incoming grav

Sang Pyo Kim

We apply the de Broglie-Bohm interpretation to the Wheeler-DeWitt equation for the quantum FRW cosmological model with a minimal massless scalar field. We find that the quantum FRW cosmological model has quantum potential dominated solutions that avoid the initial and the final cosmological singularities. It is suggested that the quantum potential and the ba

José F. Cariñena, Héctor Figueroa

Using supervector fields and graded forms along a morphism, we study the geometry of ordinary differential superequations, extend the formalism of higher order Lagrangian mechanics to the graded context and prove a generalization of Noether&#39;s theorem.

José F. Cariñena

This paper points out the usefulness of the concept of derivation along a map in many problems in Geometry and Physics. In particular it will be shown that this approach allows us to translate the usual concepts arising in Geometrical Mechanics, when appropriately written in a new way, to the framework of Supermechanics.

José F. Cariñena, Hector Figueroa

We take advantage of different generalizations of the tangent manifold to the context of graded manifolds, together with the notion of super section along a morphism of graded manifolds, to obtain intrinsic definitions of the main objects in supermechanics such as, the vertical endomorphism, the canonical and the Cartan&#39;s graded forms, the total time der

Per Arne Rikvold, Gregory Brown, M. A. Novotny, Andrzej Wieckowski

We discuss applications of statistical-mechanical lattice-gas models to study static and dynamic aspects of electrochemical adsorption. The strategy developed to describe specific systems includes microscopic model formulation, calculation of zero-temperature phase diagrams, numerical simulation of thermodynamic and structural quantities at nonzero temperatu

F. Mancini, D. Villani, H. Matsumoto

In the low doping region an incommensurate magnetic phase is observed in LSCO. By means of the composite operator method we show that the single-band 2D Hubbard model describes the experimental situation. In the higher doping region, where experiments are not available, the incommensurability is depressed owing to the van Hove singularity near the Fermi leve

Lorenz Bartosch, Peter Kopietz

We calculate the exact Green function of a special model of N coupled Luttinger chains with arbitrary interchain hopping t_{perp}. The model is exactly solvable via bosonization if the interchain interaction does not fall off in the direction perpendicular to the chains. For any finite N we find Luttinger liquid behavior and explicitly calculate the anomalou

Thorsten Koslowski, Walter Kob, Katharina Vollmayr

We present a computational study of the electronic properties of amorphous SiO2. The ionic configurations used are the ones generated by an earlier molecular dynamics simulations in which the system was cooled with different cooling rates from the liquid state to a glass, thus giving access to glass-like configurations with different degrees of disorder [Phy

R. Mélin, F. Fominaya

We analyze the specific heat variations as a function of an external magnetic field of a simple model of superlattice that includes (i) in--plane ferromagnetic exchange, (ii) interplane ferromagnetic exchange, (iii) dipolar interactions, (iv) magnetocristalline anisotropy. The calculations are carried out at the spin wave level. The interplay between the exi

Klaus Doll, Michael Dolg, Peter Fulde, Hermann Stoll

We apply ab-initio quantum chemical methods to calculate correlation effects on cohesive properties of NiO, thereby extending a recently proposed scheme to transition metal oxides with partially filled $d$-bands. We obtain good agreement with experiment for the cohesive energy and show that the deviation of the lattice constant at the Hartree-Fock level is m

Otto B. Bischof, Robert H. Becker

Using the NVSS radio catalog, we have searched for radio emission from 4079 quasars taken from the 1996 version of the Veron-Cetty and Veron (1996) quasar catalog. The comparison resulted in the positive detection of radio emission from 799 quasars. Of these, 168 are new radio detections. Examination of the radio luminosities shows a dramatic increase in the

Kristof Petrovay

A model for homogeneous anisotropic incompressible turbulence is proposed. The model generalizes the GISS model of homogeneous isotropic turbulence; the generalization involves the solution of the GISS equations along a set of integration paths in wavenumber (k-) space. In order to make the problem tractable, these integration paths (&#34;cascade lines&#34;)

P. M. Ogle, M. H. Cohen, J. S. Miller, H. D. Tran

We have discovered scattered broad Balmer emission lines in the spectrum of Cygnus A, using the Keck II telescope. Broad H-alpha appears in polarized flux from components on either side of the nucleus, and to a lesser extent in the nucleus. The full-width at half-maximum of broad H-alpha is 26,000 km/s, comparable to the widest emission lines seen in broad-l

W. Zhang, T. E. Strohmayer, J. H. Swank

Kilo-Hertz (kHz) Quasi-periodic oscillations (QPOs) have been discovered in the X-ray fluxes of 8 low-mass X-ray binaries (LMXBs) with the Rossi X-ray Timing Explorer (RXTE). The characteristics of these QPOs are remarkably similar from one source to another. In particular, the highest observed QPO frequencies for 6 of the 8 sources fall in a very narrow ran

M. Tavani

We consider possible interpretations of the recently detected X- ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray afterglows. We show that models based on adiabatic expansion of relativistic forward shocks require very efficient particle energ

M. Sauvage, T. X. Thuan, P. O. Lagage

We have observed the Blue Compact Dwarf (BCD) galaxy He 2-10 in the 10 microns mid-infrared (MIR) atmospheric window using broad-band filters centered at lambda=10.1 microns and lambda=11.65 microns. In both filters, only the galaxy&#39;s central regions were detected. One of the UV emitting regions is not detected, implying an older age. The central region

S. Borgani, L. N. da Costa, W. Freudling, R. Giovanelli

Recently, peculiar velocity measurements became available for a new sample of galaxy clusters. From an accurately calibrated Tully-Fisher relation for spiral galaxies, we compute the rms cluster peculiar velocity and compare it to the linear theory predictions of COBE-normalized low-density and open CDM models (LambdaCDM and OCDM, respectively). Confidence l

M. Pohl, R. C. Hartman, B. B. Jones, P. Sreekumar

In this paper we present a statistical analysis of the gamma-ray spectra of flat-spectrum radio quasars (FSRQ) compared to those of BL Lacs. The average spectra and possible systematic deviations from power-law behaviour are investigated by summing up the intensity and the power-law fit statistic for both classes of objects. We also compare the time-averaged

Enrique Arrondo

We characterize the double Veronese embedding of P^n as the only variety that, under certain general conditions, can be isomorphically projected from the Grassmannian of lines in P^{2n+1} to the Grassmannian of lines in P^{n+1}.

Elizabeth Gasparim

In this work we study the topology of holomorphic rank two bundles over complex surfaces. We consider bundles that are constructed by glueing and show that under certain conditions the topology of the bundle does not depend on the glueing. We present a simple classification of bundles on blown-up surfaces.

Ashoke Sen, Savdeep Sethi

We study certain compactifications of the type I string on K3. The three topologically distinct choices of gauge bundle for the type I theory are shown to be equivalent to type IIB orientifolds with different choices of background anti-symmetric tensor field flux. Using a mirror transformation, we relate these models to orientifolds with fixed seven planes,

M. S. Fayache, Y. Y. Sharon, L. Zamick

The energies and transition rates to $J=1^{+} T=1$ and $J=2^{+} T=0,1$ states in ^{12}C with matrix elements fitted to realistic $G$ matrix elements obtained in non-relativistic approaches are studied. Then the effects of varying the strengths of the two-body tensor and spin-orbit interactions are also considered. The calculations are done in both a small sp

H. M. Asatrian, G. K. Yeghiyan, A. N. Ioannissian

The direct CP-violations in $SU(2)_{L}\times SU(2)_{R} \times U(1)$ model and two-Higgs doublet extension of the standard model for $b \to dγ$ and $b \to sγ$ decays are investigated. The calculated value of CP-asymmetry for these two models and for $b \to dγ$ and $b \to sγ$ decays for the wide range of parameters may exceed the value, predicted by the standa

Seth Lloyd

This paper discusses fully coherent quantum feedback control, in which the sensors, controller, and actuators are quantum systems and interact coherently with the system to be controlled: as a result, the entire feedback loop is coherent. Unlike conventional semiclassical feedback control of quantum systems, feedback control by quantum controllers is not sto

V. A. Slobodenyuk

It is studied time dependence of the evolution operator kernel for the Schrödinger equation with a help of the Schwinger -- DeWitt expansion. For many of potentials this expansion is divergent. But there were established nontrivial potentials for which the Schwinger -- DeWitt expansion is convergent. These are, e.g., V=g/x^2, V=-g/cosh^2 x, V=g/sinh^2 x, V=g

L. Andrianopoli, R. D&#39;Auria, S. Ferrara

The absolute (moduli-independent) U-invariants of all N>2 extended supergravities at D=4 are derived in terms of (moduli-dependent) central and matter charges. These invariants give a general definition of the ``topological&#39;&#39; Bekenstein-Hawking entropy formula for extremal black-holes and reduce to the square of the black-hole ADM mass for ``fixed sc

Parthasarathi Majumdar

Starting with free massless scalar and spinor fields described by a globally N=1 supersymmetric action, infalling on a Schwarzschild black hole, the outgoing Hawking radiation is shown to break supersymmetry spontaneously, exactly as induced by a heat bath in Minkowski space, with no generation of Nambu-Goldstone fermions.

A. A. Andrianov, N. V. Romanenko

The fine-tuning principles are analyzed in search for estimations of heavy particle masses in the left-right (LR) symmetric model. The modification of Veltman condition based on the hypothesis of the compensation between fermion and boson vacuum energies within the LR Model multiplets is proposed. The hypothesis is supplied with the requirement of the stabil

M. Tatsuno, Y. Aizawa

We theoretically investigate long-term potentiation (LTP) in the hippocampus using a simple model of a neuron stimulated by three different time-structured input signals (regular, Markov, and chaotic). The synaptic efficacy change is described taking into account both N-methyl-D-aspartate (NMDA) and non-NMDA receptors. The experimental results are successful

Martin Janssen

This review is intended to give a pedagogical and unified view on the subject of the statistics and scaling of physical quantities in disordered electron systems at very low temperatures. Quantum coherence at low temperatures and randomness of microscopic details can cause large fluctuations of physical quantities. In such mesoscopic systems a localization-d

T. Shahbaz, M. Somers, B. Yudin, T. Naylor

We have obtained I, J, H and K band light curves of the recurrent nova T CrB. We find that we can only fit the $J$ band light curve with a Roche-lobe filling secondary star and a dark spot of radius 11-26 derees (90 per cent confidence) centred at the inner Lagrangian point. We obtain limits to the binary inclination of 38-46 degrees (90 per cent confidence)

Scott Hill, William K. Wootters

The ``entanglement of formation&#39;&#39; of a mixed state of a bipartite quantum system can be defined in terms of the number of pure singlets needed to create the state with no further transfer of quantum information. We find an exact formula for the entanglement of formation for all mixed states of two qubits having no more than two non-zero eigenvalues,

T. Blank, W. Hollik

Electroweak precision observables are calculated at complete 1-loop order in the extension of the standard model by an extra Higgs triplet, where the $ρ$-parameter can be different from unity already at the tree level. One additional data point is required for fixing the input parameters. In the on-shell renormalization scheme the leptonic mixing angle $\sin

Lu-Ming Duan, Guang-Can Guo

A scheme is proposed for protecting quantum states from both independent decoherence and cooperative decoherence. The scheme operates by pairing each qubit (two-state quantum system) with an ancilla qubit and by encoding the states of the qubits into the corresponding coherence-preserving states of the qubit-pairs. In this scheme, the amplitude damping (loss

Bogdan A. Dobrescu

I present a realistic model of dynamical supersymmetry breaking, in which a $U(1)_{B-L}$ gauge interaction communicates supersymmetry breaking to the standard fields. A distinctive superpartner spectrum is predicted in this model.

M. Matsuo, T. Døssing, E. Vigezzi, S. Åberg

The nearest neighbour level spacing distribution and the $Δ_3$ statistics of level fluctuations associated with very high spin states ($I \gesim 30$) in rare-earth deformed nuclei are analysed by means of a cranked shell model. The many particle-many hole configurations created in the rotating Nilsson potential are mixed by the surface-delta two-body residua

Howard E. Haber, Tao Han, Frank S. Merritt, John Womersley

We examine the prospects for discovering and elucidating the weakly-coupled Higgs sector at future collider experiments. The Higgs search consists of three phases: (i) discovery of a Higgs candidate, (ii) verification of the Higgs interpretation of the signal, and (iii) precision measurements of Higgs sector properties. The discovery of one Higgs boson with

S. -T. Sung

Several comments are given to previous proofs of the generalised second law of thermodynamics: black hole entropy plus ordinary matter entropy never decreases for a thermally closed system. Arguments in favour of its truism are given in the spirit of conventional thermodynamics.

Victor M. Yakovenko

General topologically invariant microscopical expressions for quantum numbers of particle-like solitons (&#34;skyrmions&#34;) are derived for a class of (2+1)D models. Skyrmions are either half-integer spin fermions with odd electric charge or integer spin bosons with even charge. So they cannot be Anderson&#39;s spinons or holons. General results are exempl

F. Kun, G. Bardos

We investigate the internal anisotropy of collision cascades arising from the branching structure. We show that the global fractal dimension cannot give an adequate description of the geometrical structure of cascades because it is insensitive to the internal anisotropy. In order to give a more elaborate description we introduce an angular correlation functi

Daniel J. H. Chung, Glennys R. Farrar, Edward W. Kolb

We solve the coupled Boltzmann equation for the system of light photinos interacting with pions and $R^0$&#39;s (the gluon-gluino bound state) to determine the relic abundance of light photinos in the light gaugino scenario. Cosmology bounds the ratio r of the R^0 mass to the photino mass to be less than about 1.8. We also use a model Lagrangian embodying cr

Daniel C. Cohen, Alexander I. Suciu

Let A be an arrangement of complex hyperplanes. The fundamental group of the complement of A is determined by a braid monodromy homomorphism from a finitely generated free group to the pure braid group. Using the Gassner representation of the pure braid group, we find an explicit presentation for the Alexander invariant of A. From this presentation, we obtai

Piotr Popowski, Andrew Gould

We present a mathematical analysis of the statistical parallax method. The method yields physical insight into the maximum-likelihood determinations of the luminosity and velocity distribution and enables us to conduct a vigorous Monte Carlo investigation into various systematic effects. We apply our analytic formalism to the RR Lyrae sample of Layden et al.

F. de Campos, S. M. Lietti, S. F. Novaes, R. Rosenfeld

We present sensitivity limits on the coefficients of a dimension-6 effective Lagrangian that parametrizes the possible effects of new physics beyond the Standard Model. Our results are based on the study of the process $e^+ e^- \to W^+ W^- γ$ at LEP2 and NLC energies. In our calculations, we include all the new anomalous interactions, involving vector and Hi

Pavel Etingof, Alexander Varchenko

The classical Yang-Baxter equation (CYBE) is an algebraic equation central in the theory of integrable systems. Its solutions were classified by Belavin and Drinfeld. Quantization of CYBE led to the theory of quantum groups. A geometric interpretation of CDYB was given by Drinfeld and gave rise to the theory of Poisson-Lie groups. The classical dynamical Yan

Hans Henrik Rugh

We present a geometric and dynamical approach to the micro-canonical ensemble of classical Hamiltonian systems. We generalize the arguments in \cite{Rugh} and show that the energy-derivative of a micro-canonical average is itself micro-canonically observable. In particular, temperature, specific heat and higher order derivatives of the entropy can be observe

G. G. Pavlov, V. E. Zavlin

The properties of X-ray radiation from the polar caps predicted by the radio pulsar models depend on the surface chemical composition, magnetic field and star&#39;s mass and radius as well as on the cap temperature, size and position. Fitting the radiation spectra and light curves with the neutron star atmosphere models enables one to infer these parameters.

V. C. de Andrade, J. G. Pereira

In the context of a gauge theory for the translation group, we have obtained, for a spinless particle, a gravitational analog of the Lorentz force. Then, we have shown that this force equation can be rewritten in terms of magnitudes related to either the teleparallel or the riemannian structures induced in spacetime by the presence of the gravitational field

G. Herrera, J. Magnin

We study Lambda_c/Lambda}_c-bar production asymmetries in pp and pi- p collisions using a recently proposed two component model. The model includes heavy baryon production by the usual mechanism of parton fusion and fragmentation plus recombination of valence and sea quarks from the beam and target hadrons. We compare our results with experimental data on as

E Gunzig, R Maartens, A Nesteruk

We present a simple and thermodynamically consistent cosmology with a phenomenological model of quantum creation of radiation due to vacuum decay. Thermodynamics and Einstein&#39;s equations lead to an equation in which $H$ is determined by the particle number $N$. The model is completed by specifying the particle creation rate $Γ=\dot{N}/N$, which leads to

G. Veneziano

An inhomogeneous version of pre--Big Bang cosmology emerges, within string theory, from quite generic initial conditions, provided they lie deeply inside the weak-coupling, low-curvature regime. Large-scale homogeneity, flatness, and isotropy appear naturally as late-time outcomes of such an evolution.

E. L. Bratkovskaya, W. Cassing, U. Mosel

We analyse the production and propagation of pions and kaons in heavy-ion reactions from 0.8 -- 1.8~A$\cdot$GeV within a coupled channel transport approach including the kaon production channels $BB \to K^+YN, πB\to K^+Y, BB \to NN K \bar{K}, πB\to N K\bar{K}, K^+B\to K^+B $ and $ππ\to K \bar{K}$. Assuming the hyperon selfenergy to be 2/3 of the nucleon self

Saurabh D. Rindani, J. P. Singh

Anomalous CP-odd W+W-Z couplings can give rise to a forward-backward asymmetry in the Z angular distribution in the e+e- centre-of-mass frame in the process e+e- -> nu nubar Z. Of the three CP-odd couplings possible, only the imaginary part of one of the couplings, f_4^Z, which is C odd and P even, contributes to the forward-backward asymmetry. It is found t

I. L. Buchbinder, E. I. Buchbinder, E. A. Ivanov, S. M. Kuzenko

We present, in the N=2, D=4 harmonic superspace formalism, a general method for constructing the off-shell effective action of an N=2 abelian gauge superfield coupled to matter hypermultiplets. Using manifestly N=2 supersymmetric harmonic supergraph techniques, we calculate the low-energy corrections to the renormalized one-loop effective action in terms of