November 1998 arXiv papers — page 6

Jerome A. Orosz, Richard A. Wade, Jason J. B. Harlow, John R. Thorstensen

We have made extensive spectroscopic and photometric observations of PG 1224+309, a close binary containing a DA white dwarf primary and an M4+ secondary. The H alpha line is in emission due to irradiation of the M-star by the hot white dwarf and is seen to vary around the orbit. From the radial velocities of the H alpha line we derive a period of P = 0.2586

Phil Arras, Dong Lai

We study neutrino-nucleon scattering and absorption in a dense, magnetized nuclear medium. These are the most important sources of neutrino opacity governing the cooling of a proto-neutron star in the first tens of seconds after its formation. Because the weak interaction is parity violating, the absorption and scattering cross-sections depend asymmetrically

Shai Kaspi, Hagai Netzer

We present a new scheme for modeling the broad line region in active galactic nuclei. It involves photoionization calculations applied to a number of variable emission lines at {\it all times}. We demonstrate how fitting all lines simultaneously provide strong constraints on several of the more important parameters, such as the density and column density, an

M. E. J. Newman, Paolo Sibani

Using data drawn from large-scale databases, a number of interesting trends in the fossil record have been observed in recent years. These include the average decline in extinction rates throughout the Phanerozoic, the average increase in standing diversity, correlations between rates of origination and extinction, and simple laws governing the form of survi

Zurab Berezhiani, Anna Rossi

The atmospheric neutrino data imply large mixing between the $\nu_\mu$ and $\nu_\tau$ states, $\theta_{23} = (45\pm 12)^\circ$, while the MSW solution to the solar neutrino problem needs very small mixing angle $\theta_{12} = (2\pm 1)^\circ$. In the quark sector the situation is rather opposite -- the 23 mixing is tiny, $\theta_{23}\simeq 2^\circ$, versus re

David De Wit, Louis H Kauffman, Jon R Links

We introduce and study in detail an invariant of (1,1) tangles. This invariant, derived from a family of four dimensional representations of the quantum superalgebra U_q[gl(2|1)], will be referred to as the Links-Gould invariant. We find that our invariant is distinct from the Jones, HOMFLY and Kauffman polynomials (detecting chirality of some links where th

B. V. Andryushechkin, K. N. Eltsov, V. M. Shevlyuga

The structure of AgCl formed in the course of chlorine adsorption on Ag(111) surface was studied by STM. For the first time atomic resolution STM images of silver chloride were obtained. The silver chloride was detected as small (30-60 A in diameter) islands located on the atomic terraces. The upper plane of the islands was found to be AgCl(111) with interat

F. Sols, J. Sánchez-Cañizares

We study theoretically electronic transport through a normal metal-- superconductor (NS) interface and show that more than one conductance may be defined, depending on the pair of chemical potentials whose difference one chooses to relate linearly to the current. We argue that the situation is analogous to that found for purely normal transport, where differ

H. Nakao, M. Nishi, Y. Fujii, T. Masuda

In doped CuGeO3 systems, such as (Cu1-xZnx)GeO3 and Cu(Ge1-xSix)O3, the spin-Peierls (SP) ordering (T<Tsp) coexists with the antiferromagnetic (AF) phase (T<TN<Tsp). Tsp decreases while TN increases with increasing x in low doping region. For higher x, however, the SP state disappears and only the AF state remains. These features are common for all the doped

R. V. E. Lovelace, M. M. Romanova, G. S. Bisnovatyi-Kogan

A model is developed for magnetic `propeller&#39;-driven outflows which cause a rapidly rotating magnetized star accreting from a disk to spin-down. Energy and angular momentum lost by the star goes into expelling most of the accreting disk matter. The theory gives an expression for the effective Alfven radius $R_A$ (where the inflowing matter is effectively

A. E. Winn

Hyperbolic versions of the integrable (1+1)-dimensional Heisenberg Ferromagnet and sigma models are discussed in the context of topological solutions classifiable by an integer `winding number&#39;. Some explicit solutions are presented and the existence of certain classes of such winding solutions examined.

Paul E. Gunnells

Let G be a torsion-free finite-index subgroup of SL(n,Z) or GL(n,Z), and let d be the cohomological dimension of G. We present an algorithm to compute the eigenvalues of the Hecke operators on the integral cohomology of degree d-1 for n = 2, 3, and 4. In addition, we describe a modification of the modular symbol algorithm of Ash-Rudolph for computing Hecke e

Thomas G. Rizzo

R-parity violation and extensions of the Standard Model gauge structure offer two non-minimal realizations of supersymmetry at low energies that can lead to similar new physics signatures at existing and future colliders. We discuss techniques that can be employed at the NLC below direct production threshold to distinguish these two new physics scenarios.

L. Chekhov, K. Palamarchuk

We investigate the two-logarithm matrix model with the potential $XΛ+α\log(1+X)+β\log(1-X)$ related to an exactly solvable Kazakov-Migdal model. In the proper normalization, using Virasoro constraints, we prove the equivalence of this model and the Kontsevich-Penner matrix model and construct the 1/N-expansion solution of this model.

Konstantina Savvidou

We define the action operator in the consistent histories formalism, as the quantum analogue of the classical action functional, for the simple harmonic oscillator case. The action operator is shown to be the generator of time transformations, and to be associated with the two types of time-evolution of the standard quantum theory: the wave-packet reduction

L Baulieu, S. L. Shatashvili

We describe topological gauge theories for which duality properties are encoded by construction. We study them for compact manifolds of dimensions four, eight and two. The fields and their duals are treated symmetrically, within the context of field--antifield unification. Dual formulations correspond to different gauge-fixings of the topological symmetry. W

Alessandro Strumia, Nikolaos Tetradis

We present a consistent calculation of bubble-nucleation rates in theories of two scalar fields. Our approach is based on the notion of a coarse-grained free energy that incorporates the effects of fluctuations with momenta above a given scale k. We establish the reliability of the method for a variety of two-scalar models and confirm the conclusions of prev

F. Gangemi, G. Montagna, M. Moretti, O. Nicrosini

The six-fermion production processes $e^+e^-\to q\bar q l^+ l^-ν\barν$, with all the lepton flavours and $q=u,d,c,s$, relevant to the study of the intermediate-mass Higgs boson at future $e^+e^-$ linear colliders, are analysed. A Monte Carlo program, taking into account the whole set of tree-level scattering amplitudes and the relevant radiative effects, is

D. S. Salopek

Strongly coupled gravitational systems describe Einstein gravity and matter in the limit that Newton&#39;s constant G is assumed to be very large. The nonlinear evolution of these systems may be solved analytically in the classical and semiclassical limits by employing a Green function analysis. Using functional methods in a Hamilton-Jacobi setting, one may

A. B. Balantekin, M. A. Candido Ribeiro, A. N. F. Aleixo

Self-similar potentials generalize the concept of shape-invariance which was originally introduced to explore exactly-solvable potentials in quantum mechanics. In this article it is shown that previously introduced algebraic approach to the latter can be generalized to the former. The infinite Lie algebras introduced in this context are shown to be closely r

Dmitry V. Strekalov, Yoon-Ho Kim, Yanhua Shih

The state of the signal-idler photon pair of spontaneous parametric down conversion(SPDC) is a typical nonlocal entangled pure state with zero entropy. The precise correlation of the subsystems is completely described by the state. However, it is an experimental choice to study only one subsystem and to ignore the other. What can we learn about the measured

W. L. Power, I. C. Percival

One of the biggest problems faced by those attempting to combine quantum theory and general relativity is the experimental inaccessibility of the unification scale. In this paper we show how incoherent conformal waves in the gravitational field, which may be produced by quantum mechanical zero-point fluctuations, interact with the wavepackets of massive part

Samuel J. Lomonaco

The recent application of the principles of quantum mechanics to cryptography has led to a remarkable new dimension in secret communication. As a result of these new developments, it is now possible to construct cryptographic communication systems which detect unauthorized eavesdropping should it occur, and which give a guarantee of no eavesdropping should i

G. D&#39;Agostini

I review the problem of the choice of the priors from the point of view of a physicist interested in measuring a physical quantity, and I try to show that the reference priors often recommended for the purpose (Jeffreys priors) do not fit to the problem. Although it may seem surprising, it is easier for an ``experienced physicist&#39;&#39; to accept subjecti

G. Fiorentini

In this report, centered on the activities within the MURST-PRIN project &#34;Fisica teorica del nucleo e dei sistemi a più corpi&#34; we discuss recent advances on the following items: i)neutrinos as probes of the solar interior and of other astrophysical objects; ii)neutrinos as probes of physics beyond the Standard Model of electroweak interactions; iii)t

J. Sollfrank

The thermal model is commonly used in two different ways for the description of hadron production in ultra-relativistic heavy ion collision. One is the application of the thermal model to 4pi integrated data and the other is the thermal description of central dN/dy ratios. While the first method implicitly assumes global equilibrium the other scenario assume

TAGX Collaboration, M. A. Kagarlis, Z. Papandreou, G. M. Huber

A large reduction of the rho^0 mass in the nuclear medium is reported, inferred from dipion photoproduction spectra in the 1 GeV region, for the reaction 3He(gamma,pi+ pi-)X with a 10% duty factor tagged-photon beam and the TAGX multi-particle spectrometer. The energy range covered (800 < E(gamma) < 1120 MeV) lies mostly below the free rho^0 production thres

N. G. Marchuk

An equation, we call Dirac gamma-equation, is introduced with the help of the mathematical tools connected with the Clifford algebra. This equation can be considered as a generalization of the Dirac equation for the electron. Some features of Dirac gamma- equation are investigated (plane waves, currents, canonical forms). Furthermore, on the basis of local g

N. G. Marchuk

We introduce an equation named matrix Dirac equation which can be considered as a generalization of Dirac equation for an electron. The liaison between matrix Dirac equation and standard Dirac equation is discussed. We write a lagrangian from which matrix Dirac equation can be derived. This lagrangian is invariant under global unitary transformations of vari

Henry C. King

This paper studies the configuration space of all possible positions of a linkage in R^n. For example, it shows that for every compact algebraic set, there is a linkage whose configuration space is analytically isomorphic to a finite number of copies of the algebraic set. If flexible edges are allowed, any compact set given by polynomial equalities and inequ

Carlos A. M. Andre

Let F be a finite field with q elements, let A be a finite dimensional F-algebra and let J=J(A) be the Jacobson radical of A. Then G=1+J is a p-group, where p is the characteristic of F. We refer to G as an F-algebra group. A subgroup H of G is said to be an algebra subgroup of G if H=1+U for some multiplicatively closed F-subspace of J. In this paper, we pa

Anne V. Shepler

Let G be a finite group of complex n by n unitary matrices generated by reflections acting on C^n. Let R be the ring of invariant polynomials, and χbe a multiplicative character of G. Let Ω^χbe the R-module of χ-invariant differential forms. We define a multiplication in Ω^χand show that under this multiplication Ω^χhas an exterior algebra structure. We also

Phung Ho Hai

We introduce the notion of characters of comodules over coribbon Hopf algebras. The case of quantum groups of type $A_n$ is studied. We establish a characteristic equation for the quantum matrix and a q-analogue of Harish-Chandra- Itzykson-Zuber integral

Brian R. Greene, C. I. Lazaroiu, Mark Raugas

We investigate the classical moduli space of D-branes on a nonabelian Calabi-Yau threefold singularity and find that it admits topology-changing transitions. We construct a general formalism of worldvolume field theories in the language of quivers and give a procedure for computing the enlarged Kahler cone of the moduli space. The topology changing transitio

George Thompson

The path integral generalization of the Casson invariant as developed by Rozansky and Witten is investigated. The path integral for various three manifolds is explicitly evaluated. A new class of topological observables is introduced that may allow for more effective invariants. Finally it is shown how the dimensional reduction of these theories corresponds

Yu. Malyuta, T. Obikhod

The Nakamura&#39;s algorithm is applied to compute the Hilbert scheme for the D-brane model 1/13(1,2,10).

F. Benatti, R. Floreanini

The neutral kaon system can be effectively described by non-unitary, dissipative, completely positive dynamics that extend the usual treatment. In the framework of open quantum systems, we show how the origin of these non-standard time evolutions can be traced to the interaction of the kaon system with a large environment. We find that D-branes, effectively

R. Amorim, N. R. F. Braga, R. Thibes

In the generalized Schwinger model the vector and axial vector currents are linearly coupled, with arbitrary coefficients, to the gauge connection. Therefore it represents an interesting example of a theory where both gauge anomalies and anomalous diver gences of global currents show up in general. We derive results for these two kinds of quantum corrections

Iain A. Bertram

Searches for new resonant phenomena on top of a continuum spectra need to make assumptions regarding the shape of the continuum spectra. The Ansatz function method used in previous searches for new particles decaying to dijets is investigated and found to have inherent biases that cause the 95% confidence limits on the signal cross-section to be miss-measure

Keith A. Olive, David Thomas

We compute the big bang nucleosynthesis limit on the number of light neutrino degrees of freedom in a model-independent likelihood analysis based on the abundances of He4 and Li7. We use the two-dimensional likelihood functions to simultaneously constrain the baryon-to-photon ratio and the number of light neutrinos for a range of He4 abundances $Y_p$ = 0.225

M. Raidal, P. M. Zerwas

In supersymmetric grand unified theories, light higgsino multiplets generally exist in addition to the familiar chargino/neutralino multiplets of the minimal supersymmetric extension of the Standard Model. The new multiplets may include doubly charged states $\tildeΔ^{\pm\pm}$ and $\tildeδ^{\pm\pm}$. We study the properties and the production channels of the

J. C. Pati

By way of paying tribute to Abdus Salam, I recall the ideas of higher unification that he and I initiated. I discuss the current status of those ideas in the light of recent developments, including those of: (a) gauge coupling unification, (b) discovery of neutrino-oscillation at SuperKamiokande, and (c) ongoing searches for proton decay. It is remarked that

W. Poeschl, B. Mueller

In a fully relativistic approach, a RLSM description of nuclei colliding at ultra-relativistic energies can be formulated within the framework of a classical transport theory. The valence quarks of the nucleons are described through collections of classical point-like particles moving in the continuum. They are coupled to soft gluon fields which are describe

R. J. M. Covolan, M. S. Soares

Experimental rates of W and dijets diffractively produced at the Tevatron Collider have recently become available. We use parametrizations of the pomeron structure function obtained from HERA data by two different schemes to compare theoretical expectations with the measured rates.

G. Montagna, M. Moretti, O. Nicrosini, A. Pallavicini

This work deals with the computation of electron pair correction to small angle Bhabha scattering, in order to contribute to the improvement of luminometry precision at LEP/SLC below 0.1% theoretical accuracy. The exact QED four-fermion matrix element for $e^+e^-\to e^+e^-e^+e^-$, including all diagrams and mass terms, is computed and different Feynman graph

K. Takayama, M. Oka

Hyperon non-leptonic weak decay amplitudes are studied in the chiral perturbation theory. The weak interaction vertices caused by the four quark operators are substituted by the products of the hadronic currents and by the phenomenologically introduced weak Hamiltonian of hadron operators. Our study suggests the improvement of the theoretical prediction for

Stefan Dittmaier

The status of precision calculations for the processes e+e- --> WW --> 4 fermions is reviewed, paying particular attention to questions of gauge invariance and recent progress concerning photonic radiative corrections.

A. Gomez Nicola, V. Galan-Gonzalez

We extend chiral perturbation theory to study a meson gas out of thermal equilibrium. Assuming that the system is initially in equilibrium below the critical temperature and working within the Schwinger-Keldysh contour technique, we define consistently the time-dependent pion decay functions, the counterparts of the pion decay constants, and calculate them u

G. Brooijmans

The formalism for neutrino flavor change induced by lepton family number violating interactions is developed for the three-neutrino case, and used to derive the corresponding flavor change probabilities in matter. Applied to the solar and atmospheric neutrino fluxes, it is argued that the observed anomalies, including the zenith dependence for the atmospheri

C. H. Chang, T. F. Feng, L. Y. Shang

A R-parity breaking SUSY model characterized by an effective bilinear violation with only $τ$-lepton number breaking in the superpotential is outlined. The CP-odd Higgs boson masses and those of charged Higgs bosons are discussed. In the model, several interesting mass mixings else such as the mixing between $τ$ lepton and charginos etc in the model are disc

P. Chen, N. Christ, G. Fleming, A. Kaehler

We report on simulations of quenched QCD using domain wall fermions, where we focus on basic questions about the formalism and its ability to produce expected low energy hadronic physics for light quarks. The work reported here is on quenched $8^3 \times 32$ lattices at $β= 5.7$ and 5.85, using values for the length of the fifth dimension between 10 and 48.

Steven R. Wasserbaech

The measurements of the mean lifetime of the tau lepton are reviewed. The conditions for measuring the lifetime at various e+e- colliders are compared and the analysis methods are briefly described. The new developments since the previous Workshop on Tau Lepton Physics are listed. The world average is tau_tau = 290.5 +- 1.0 fs. The LEP experiments dominate t

NuTeV Collaboration, R. B. Drucker

Preliminary results from a search for neutral heavy leptons in the NuTeV experiment at Fermilab. The upgraded NuTeV neutrino detector for the 1996-1997 run included an instrumented decay region for the NHL search which, combined with the NuTeV calorimeter, allows detection in several decay modes (mu-mu-nu, mu-e-nu, mu-pi, e-pi, and e-e-nu). We see no evidenc

Nikolai V. Mitskievich

Skew-symmetric massless fields, their potentials being $r$-forms, are close analogues of Maxwell&#39;s field (though the non-linear cases also should be considered). We observe that only two of them ($r=$2 and 3) automatically yield stress-energy tensors characteristic to normal perfect fluids. It is shown that they naturally describe both non-rotating ($r=2

Michael C. Ashworth, Sean A. Hayward

We consider two proposals for defining black hole entropy in spherical symmetry, where the horizon is defined locally as a trapping horizon. The first case, boundary terms in a dual-null form of the reduced action in two dimensions, gives a result that is proportional to the area. The second case, Wald&#39;s Noether current method, is generalized to dynamic

P E Kornilovitch

Anisotropic electron-phonon interaction is shown to lead to the anisotropic polaron effect. The resulting anisotropy of the polaron band is an exponential function of the electron-phonon coupling and might be as big as $10^3$. This also makes anisotropy very sensitive to small changes of coupling and implies wide variations of anisotropy among compounds of s

Catherine Pepin, Patrick. A. Lee

It is now well established that Zn doping of high-$T_C$ cuprates reduces their $T_C$ and triggers the appearence of a spin glass phase. In this context, we have solved exactly the problem of N non magnetic impurities in the staggered flux phase of the Heisenberg model which we assume to be a good mean-field approximation for the spin-gap phase of the cuprate

J. Vidal, R. Mosseri, J. Bellissard

We propose a class of exactly solvable anisotropic tight-binding models on an infinite-dimensional hypercube. The energy spectrum is analytically computed and is shown to be fractal and/or absolutely continuous according to the value hopping parameters. In both cases, the spectral and diffusion exponents are derived. The main result is that, even if the spec

T. Dittrich, B. Mehlig, H. Schanz, Uzy Smilansky

We study the spectral statistics for extended yet finite quasi 1-d systems which undergo a transition from periodicity to disorder. In particular we compute the spectral two-point form factor, and the resulting expression depends on the degree of disorder. It interpolates smoothly between the two extreme limits -- the approach to Poissonian statistics in the

S. Caprara, A. Perali, M. Sulpizi

Within the framework of the Charge Density Wave Quantum Critical Point (CDW-QCP) scenario for high-T_c superconductors (HTCS), we introduce a model for tight-binding electrons coupled to quasi-critical fluctuations. In the normal state our model reproduces features of the Fermi Surface (FS) observed in ARPES measurements on optimally doped Bi2212, such as th

Roser Valenti, Claudius Gros, V. N. Muthukumar

The possible occurrence of nonreciprocal acoustic effects in antiferromagnets in the absence of an external magnetic field is investigated using both (i) a microscopic formulation of the magnetoelastic interaction between spins and phonons and (ii) symmetry arguments. We predict for certain antiferromagnets the existence of two new nonreciprocal (non-time in

Liesbeth C. Venema, Jeroen W. G. Wildoer, Jorg W. Janssen, Sander J. Tans

Carbon nanotubes provide a unique system to study one-dimensional quantization phenomena. Scanning tunneling microscopy is used to observe the electronic wave functions that correspond to quantized energy levels in short metallic carbon nanotubes. Discrete electron waves are apparent from periodic oscillations in the differential conductance as a function of

Yasuhiro Matsushita, Ryousuke Shiina, Chikara Ishii

The spin excitations in the antiferromagnetic phase of half-filled Kondo lattice model are studied by means of the decoupling approximation for spin Green&#39;s function. The spin-wave spectrum is calculated as a function of Kondo coupling, and this is used to calculate the thermodynamic quantities at low temperatures. The Néel temperature of the form $T_{\r

I. Vekhter, P. J. Hirschfeld, J. P. Carbotte, E. J. Nicol

The density of states of a 2D d-wave superconductor in the vortex state with applied magnetic field $\bf H$ in the plane is shown to exhibit fourfold oscillations as a function of the angle of the field with respect to the crystal axes. We find further that the frequency dependence of the density of states and the temperature dependence of transport coeffici

M. Olshanii, M. Naraschewski

The existence of a geometric phase in magnetic traps can be used to Bose condense a magnetically trapped atomic gas into a vortex state. We propose an experimental setup where a magnetic trap together with a blue detuned laser beam form a multiply connected trap geometry. The local variation of the magnetic quantization axis induces a geometric or Berry&#39;

Sylvie Oliffson Kamphorst, Sonia Pinto de Carvalho

The Breathing Circle is a 2-dimensional generalization of the Fermi Accelerator. It is shown that the billiard map associated to this model has invariant curves in phase space, implying that any particle will have bounded gain of energy.

Phil Arras, Ira Wasserman

We explore the possibility that massive black holes comprise a significant fraction of the dark matter of our galaxy by studying the dissolution of galactic globular clusters bombarded by them. In our simulations, we evolve the clusters along a sequence of King models determined by changes of state resulting from collisions with the black holes. The results

H. V. Fagundes, E. Gausmann

We try to apply the cosmic crystallography method of Lehoucq, Lachieze-Rey, and Luminet to a universe model with closed spatial section of negative curvature. But the sharp peaks predicted for Einstein-de Sitter closed models do not appear in our hyperbolic example. So we turn to a variant of that method, by subtracting from the distribution of distances bet

S. Rosswog, M. Liebendoerfer, F. -K. Thielemann, M. B. Davies

We present the results of 3D Newtonian SPH simulations of the merger of a neutron star binary. The microscopic properties of matter are described by the physical equation of state of Lattimer and Swesty (LS-EOS). To test for the robustness of our results we check the sensitivity to the approximations of our model as well as to the binary system parameters. T

Michael S. Turner

For two decades the hot big-bang model as been referred to as the standard cosmology -- and for good reason. For just as long cosmologists have known that there are fundamental questions that are not answered by the standard cosmology and point to a grander theory. The best candidate for that grander theory is inflation + cold dark matter. It holds that the

V. Müller, A. G. Doroshkevich, J. Retzlaff, V. Turchaninov

The large supercluster structures obvious in recent galaxy redshift surveys are quantified using an one-dimensional cluster analysis (core sampling) and a three-dimensional cluster analysis based on the minimal spanning tree. The comparison with the LCRS reveals promising stable results. At a mean overdensity of about ten, the supercluster systems form huge

Michael S. Turner

The discovery of the cosmic microwave background (CMB) in 1964 by Penzias and Wilson led to the establishment of the hot big-bang cosmological model some ten years later. Discoveries made in 1998 may ultimately have as profound an effect on our understanding of the origin and evolution of the Universe. Taken at face value, they confirm the basic tenets of In

T. Okamoto, A. Habe

We investigate effects of time evolution of a rich cluster of galaxies on its member galactic halos in the standard cold dark matter (SCDM) universe using high resolution N-body simulations. We identify several hundred galactic halos within virial radius of our simulated cluster. We also find that a large number of halos have been tidally disrupted at z = 0.

A. A. Starobinsky

Though predictions of the simplest inflationary cosmological models with cold dark matter, flat space and approximately flat initial spectrum of adiabatic perturbations are remarkably close to observational data, we have to go beyond them and to introduce new physics not yet discovered in laboratories to account for all data. Two extensions of these models w

S. Cebrian, E. Garcia, D. Gonzalez, I. G. Irastorza

A calculation of the expected signal due to Primakoff coherent conversion of solar axions into photons via Bragg scattering in several crystal detectors is presented. The results are confronted with the experimental sensitivities of present and future experiments concluding that the sensitivity of crystal detectors does not challenge the globular cluster lim

Lloyd Knox

We explore the possible impact of galactic and extragalactic foregrounds on measurements of the cosmic microwave background (CMB). We find that, given our present understanding of the foregrounds, they are unlikely to qualitatively affect the ability of the MAP and Planck satellites to determine the angular power spectrum of the CMB, the key statistic for co

Jason X. Prochaska

We analyze Keck HIRES observations of a Lyman limit system at z=2.652 toward Q2231-00. These observations afford the most comprehensive study of the physical properties of a LL system to date. By comparing the ionic column densities for Fe^+, Fe^{++}, Si^+, and Si^{3+} against calculations derived from the CLOUDY software package, we have strictly constraine

David J. Jeffery

The gamma-ray transfer in supernovae for the purposes of energy deposition in the ejecta can be approximated fairly accurately as frequency-integrated (grey) radiative transfer using a mean opacity as shown by Swartz, Sutherland, & Harkness (SSH). In SSH&#39;s grey radiative transfer procedure (unoptimized) the mean opacity is a pure absorption opacity and i

Thomas Papenbrock, George F. Bertsch

We consider pairing in a dilute system of Fermions with a short-range interaction. While the theory is ill-defined for a contact interaction, the BCS equations can be solved in the leading order of low-energy effective field theory. The integrals are evaluated with the dimensional regularization technique, giving analytic formulas relating the pairing gap, t

T. M. R. Byrnes, V. A. Dzuba, V. V. Flambaum, D. W. Murray

If electrons had an electric dipole moment (EDM) they would induce EDMs of atoms. The ratio of the atomic EDM to the electron EDM for a particular atom is called the enhancement factor, R. We calculate the enhancement factor for the francium and gold atoms, with the results 910 plus/minus 5% for Fr and 260 plus/minus 15% for Au. The large values of these enh

Z. S. Bassi, A. LeClair

We discuss a solvable model describing an Anderson like impurity in a BCS superconductor. The model can be mapped onto an Ising field theory in a boundary magnetic field, with the Ising fermions being the quasi-particles of the Bogoliubov transformation in BCS theory. The reflection S-matrix exhibits Andreev scattering, and the existence of bound states of t

Tom Banks, Willy Fischler, Lubos Motl

We show that a subgroup of the modular group of M-theory compactified on a ten torus, implies the Lorentzian structure of the moduli space, that is usually associated with naive discussions of quantum cosmology based on the low energy Einstein action. This structure implies a natural division of the asymptotic domains of the moduli space into regions which c

Zurab Kakushadze

Motivated by the coupling unification problem, we propose a novel extension of the Minimal Supersymmetric Standard Model. One of the predictions of this extension is existence of new states neutral under SU(3)_c X SU(2)_w but charged under U(1)_Y. The mass scale for these new states can be around the mass scale of the electroweak Higgs doublets. This suggest

Chandrashekar Devchand, Jeremy Schiff

We study a family of fermionic extensions of the Camassa-Holm equation. Within this family we identify three interesting classes: (a) equations, which are inherently hamiltonian, describing geodesic flow with respect to an H^1 metric on the group of superconformal transformations in two dimensions, (b) equations which are hamiltonian with respect to a differ

Lu-Ming Duan, Guang-Can Guo

It is shown that the noise process in quantum computation can be described by spatially correlated decoherence and dissipation. We demonstrate that the conventional quantum error correcting codes correcting for single-qubit errors are applicable for reducing spatially correlated noise.

Robert Friedman, John W. Morgan

In this paper, the first of a series of three, we classify holomorphic principal G-bundles over an elliptic curve, where G is a reductive group. We also study the local and global properties of the moduli space of semistable G-bundles. We identify canonical representatives for each S-equivalence class of semistable G-bundles, and study their automorphism gro

Maxim Nazarov

For any complex classical group $G=O_N,Sp_N$ consider the ring $Z(g)$ of $G$-invariants in the corresponding enveloping algebra $U(g)$. Let $u$ be a complex parameter. For each $n=0,1,2,...$ and every partition $ν$ of $n$ into at most $N$ parts we define a certain rational function $Z_ν(u)$ which takes values in $Z(g)$. Our definition is motivated by the wor

Jean-Francois Burnol

The conductor operator acts on a function through multiplying it with the logarithm of the norm of the variable both in position and in momentum space and adding the outcomes. It makes sense at each completion of an arbitrary number field and arose in previous papers by the author where it was shown to be intimately connected with the Explicit Formula of Ana

Jean-Francois Burnol

This is a semi-expository paper on the easier aspects of the Explicit Formula for the Riemann Zeta Function. The topics reviewed here include: Weil&#39;s criterion for the Riemann Hypothesis and its probabilistic interpretation, various formulations of the contribution corresponding to the real place, Haran&#39;s version of the Explicit Formula, and the auth

Jean-Francois Burnol

I give a new derivation of the Explicit Formula for the general number field K, which treats all primes in exactly the same way, whether they are discrete or archimedean, and also ramified or not. In another token, I advance a probabilistic interpretation of Weil&#39;s positivity criterion, as opposed to the usual geometrical analogies or goals. But in the e

Vadim S. Kaplunovsky, Jacob Sonnenschein, Shimon Yankielowicz

We study BPS saturated domain walls in the supersymmetric SU(2) gauge theory. For a theory with a very light adjoint scalar (mass <~ Lambda/400) we use the perturbed N=2 Seiberg-Witten theory to calculate the actual field configuration of the domain wall. The wall has a sandwich-like five-layer structure of three distinct phases -- electric confinement, Coul

Y. Kinar, E. Schreiber, J. Sonnenschein

We compute the leading behaviour of the quark anti-quark potential from a generalized Nambu-Goto action associated with a curved space-time having an &#34;extra dimension&#34;. The extra dimension can be the radial coordinate in the AdS/CFT correspondence, the Liouville field in Polyakov&#39;s approach, or an internal dimension in MQCD. In particular, we der

Daniela Bigatti

Since the subject of noncommutative geometry is now entering maturity, we felt there is need for presentation of the material at an undergraduate course level. Our review is a zero order approximation to this project. Thus, the present paper attempts to offer some motivations and mathematical prerequisites for a deeper study or at least to serve as support i

Richard Partridge

This paper summarizes a variety of recent results on heavy quark production and decay. Considerable progress has been made by CDF and D0 in measuring top quark production and decay properties. The top quark mass been measured with an uncertainty that is less than 3%, a relative precision that is better than has been achieved for other quarks. Measurements of

Antoine Georges, Yigal Meir

The conductance through two quantum dots in series is studied using general qualitative arguments and quantitative slave-boson mean-field theory. It is demonstrated that measurements of the conductance can explore the phase diagram of the two-impurity Anderson model. Competition between the Kondo effect and the inter-dot magnetic exchange leads to a two-plat

You-Quan Li, Christian Gruber

The reply is no more necessary since the comment was already withdrawn

Ray Jayawardhana

I briefly review recent developments in the study of circumstellar debris disks, particularly at infrared and sub-millimeter wavelengths, and discuss possible avenues of research for the near future.

Victor G. Zubko

The new observational data on interstellar dust, obtained during the past few years, in particular, revised ISM elemental abundances, the polarization curve from the far UV to the near IR, spectra of dust infrared emission, extended red emission (ERE), are in serious conflict with existing dust models. We proposed here to use the regularization approach as a

Victor G. Zubko, Tracy L. Smith, Adolf N. Witt

To examine a recently proposed hypothesis that silicon nanoparticles are the source of extended red emission (ERE) in the interstellar medium, we performed a detailed modeling of the mean Galactic extinction in the presence of silicon nanoparticles. For this goal we used the appropriate optical constants of nanosized Si, essentially different from those of b

A. T. Tokunaga, N. Kobayashi

Infrared spectra at 1.9-2.5 micron and narrowband photometry of three low-mass objects, DENIS-P J0205.4-1159, J1058.7-1547, and J1228.2-1547, are presented. As shown previously by Delfosse et al. (1997, AA, 327, L25), DENIS-P J0205.4-1159 shows an absorption feature at 2.2 microns. We attribute this absorption to H_2. A simple two-parameter analysis of the K