September 2002 arXiv papers — page 25

V. V. Kiselev

We show that the Einstein-Hilbert action for the gravitational field can be obtained as a linear low-energy approximation for the dynamical massless fields in the theory with the lagrangian quadratic in the gauge field strength-tensor of spin connection under the spontaneous breaking of symmetry with a vacuum state described by an ansatz for nontrivial backg

O. Baer

The spectral flow of the overlap operator is computed numerically along a particular path in gauge field space. The path connects two gauge equivalent configurations which differ by a gauge transformation in the non-trivial class of pi_4(SU(2)). The computation is done with the SU(2) gauge field in the fundamental, the 3/2, and the 5/2 representation. The nu

C. Bernard, T. Burch, C. DeTar, Steven Gottlieb

We summarize our measurement of the mass of the exotic $1^{-+}$ hybrid meson using an improved Kogut-Susskind action. We show results from both quenched and dynamical quark simulations and compare with results from Wilson quarks. Extrapolation of these results to the physical quark mass allows comparison with experimental candidates for the $1^{-+}$ hybrid m

Matthew Wingate, Junko Shigemitsu, G. Peter Lepage, Christine Davies

Last year we proposed using staggered fermions as the light quarks, combined with nonrelativistic heavy quarks, in simulations of heavy-light mesons. A first round of tests which focuses on the B_s meson has been completed using quenched lattices, and results are presented here for the kinetic B_s mass, the B_s^* - B_s splitting, and f_{B_s}. The next projec

J. C. Osborn

We show how a variant of the Hubbard model can be simulated using a meron-cluster algorithm. This provides a major improvement in our ability to determine the behavior of these types of models. We also present some results that clearly demonstrate the existence of a superconducting state in this model.

K. Holland, P. Minkowski, M. Pepe, U. -J. Wiese

We discuss theories with the exceptional centerless gauge group G(2), paying attention to confinement and the pattern of chiral symmetry breaking. Exploiting the Higgs mechanism to break the symmetry down to SU(3), we also present how the familiar features of confinement and chiral symmetry breaking of SU(3) gauge theories reemerge. G(2) gauge theories show

A. Abada, D. Becirevic, Ph. Boucaud, G. Herdoiza

We present the results of the first direct determination of the g_{D^* D pi} coupling using lattice QCD. From our simulations in the quenched approximation, we obtain g_{D^* D pi} = 18.8 +/- 2.3^{+1.1}_{-2.0} and hat(g) = 0.67 +/- 0.08^{+0.04}_{-0.06}. It is in agreement with a recent experimental result from CLEO.

JLQCD collaboration, S. Hashimoto, S. Aoki, M. Fukugita

We test the one-loop chiral perturbation theory formula on unquenched lattice data of pseudoscalar meson decay constants. The chiral extrapolation including the effect of the chiral logarithm is attempted and its uncertainty is discussed.

Klejda Bega Carlos Gerardo Arroyo

Overview of SLAC Experiment E158 May-June 2002 run

L3 Collaboration

Bose-Einstein correlations in W-pair production at LEP are investigated in a data sample of 629 pb^-1 collected by the L3 detector at centre-of-mass energies of 189-209 GeV. Bose-Einstein correlations between pions within a W decay are observed and found to be in good agreement with those in light-quark Z decay. No evidence is found for Bose-Einstein correla

L3 Collaboration

Single W boson production in electron-positron collisions is studied with the L3 detector at centre-of-mass energies between 192 GeV and 209 GeV. Events with two acoplanar hadronic jets or a single energetic lepton are selected, and the single W cross section is measured. Combining the results with measurements at lower centre-of-mass energies, the ratio of

Geusa de A. Marques, V. B. Bezerra

We consider a hydrogen atom in the background spacetimes generated by an infinitely thin cosmic string and by a point-like global monopole. In both cases, we find the solutions of the corresponding Dirac equations and we determine the energy levels of the atom. We investigate how the geometric and topological features of these spacetimes leads to shifts in t

Stefan Hollands, Robert M. Wald

We define the renormalization group flow for a renormalizable interacting quantum field in curved spacetime via its behavior under scaling of the spacetime metric, $\g \to λ^2 \g$. We consider explicitly the case of a scalar field, $ϕ$, with a self-interaction of the form $κϕ^4$, although our results should generalize straightforwardly to other renormalizabl

Rafael Ferraro

The apparent discrepancy between the bending of light predicted by the equivalence principle and its corresponding value in general relativity is resolved by evaluating the deflection of light with respect to a direction that is parallel transported along the ray trajectory in 3-space. In this way the bending predicted by the equivalence principle is fulfill

Robert D. Klauber

Relativistic rotation is considered in the limit of angular velocity approaching zero and radial distance approaching infinity, such that centrifugal acceleration is immeasurably small while tangent velocity remains close to the speed of light. For this case, the predictions of the traditional approach to relativistic rotation using local co-moving Lorentz f

C. A. Duncan, A. Efrat, C. Erten, S. Kobourov

We consider the problem of simultaneous embedding of planar graphs. There are two variants of this problem, one in which the mapping between the vertices of the two graphs is given and another where the mapping is not given. In particular, we show that without mapping, any number of outerplanar graphs can be embedded simultaneously on an $O(n)\times O(n)$ gr

Clare C. Yu, Herve M. Carruzzo

We show that a glass transition, signaled by a peak in the specific heat vs. temperature, can occur because a glassy system that shows no signs of aging progresses so slowly through the energy landscape that the time needed to obtain an accurate estimate of the thermodynamic averages exceeds the observation time. We find that below the glass transition tempe

F. Kh. Abdullaev, J. G. Caputo, R. A. Kraenkel, B. A. Malomed

We consider, by means of the variational approximation (VA) and direct numerical simulations of the Gross-Pitaevskii (GP) equation, the dynamics of 2D and 3D condensates with a scattering length containing constant and harmonically varying parts, which can be achieved with an ac magnetic field tuned to the Feshbach resonance. For a rapid time modulation, we

A. Pimenov, A. V. Pronin, A. Loidl, A. Tsukada

We investigate the far-infrared and submillimeter-wave conductivity of electron-doped La_(2-x)Ce_xCuO_4 tilted 1 degree off from the ab-plane. The effective conductivity measured for this tilt angle reveals an intensive peak at finite frequency (ν~ 50 cm{-1}) due to a mixing of the in-plane and out-of-plane responses. The peak disappears for the pure in-plan

Angus MacKinnon, Andrew D Armour

We investigate the effect of quantisation of vibrational modes on a system in which the transport path is through a quantum dot mounted on a cantilever or spring such that tunnelling to and from the dot is modulated by the oscillation. We consider here the implications of quantum aspects of the motion. Peaks in the current voltage characteristic are observed

Angus MacKinnon, Andrew D Armour

A which-way device is one which is designed to detect which of 2 paths is taken by a quantum particle, whether Schrödinger's cat is dead or alive. One possible such device is represented by an Aharonov-Bohm ring with a quantum dot on one branch. A charged cantilever or spring is brought close to the dot as a detector of the presence of an electron. The c

E. Goldobin, D. Koelle, R. Kleiner

We investigate numerically a long Josephson junction with several phase pi-discontinuity points. Such junctions are usually fabricated as a ramp between an anisotropic cuprate superconductor like YBCO and an isotropic metal superconductor like Nb. From the top, they look like zigzags with pi-jumps of the Josephson phase at the corners. These pi-jumps, at cer

Jonathan M Carter, Angus MacKinnon

It has become increasingly clear that a full understanding of the physics of electrons in disordered systems requires an approach in which both disorder and interactions are taken into account. Work on small numbers of electrons has suggested that interactions can substantially increase the localisation length in 1 dimensional systems and possibly lead to de

P. I. Arseyev, N. S. Maslova, V. I. Panov, S. V. Savinov

Non-equilibrium Coulomb effects in resonant tunnelling processes through deep impurity states are analyzed. It is shown that Coulomb vertex corrections to the tunnelling transfer amplitude lead to a power-law singularity in current- voltage characteristics

F. Restagno, C. Ursini, H. Gayvallet, E. Charlaix

Aging behavior is an important effect in the friction properties of solid surfaces. In this paper we investigate the temporal evolution of the static properties of a granular medium by studying the aging over time of the maximum stability angle of submillimetric glass beads. We report the effect of several parameters on these aging properties, such as the we

Lixin He, J. B. Neaton, David Vanderbilt, Morrel H. Cohen

Structural, vibrational, and lattice dielectric properties of CdCu{3}Ti{4}O{12} are studied using density-functional theory within the local spin-density approximation, and the results are compared with those computed previously for CaCu{3}Ti{4}O{12}. Replacing Ca with Cd is found to leave many calculated quantities largely unaltered, although significant di

M. Monge, M. Biasini, G. Kontrym-Sznajd, N. Sato

The 2-dimensional angular correlations of the positron annihilation radiation (2D-ACAR) on a single crystal of LaB6 was measured for three projections. The 2D-ACAR spectra were subjected to the Van Citter-Gerhard deconvolution alghorithm. From the experimental spectra we produced the 3D k-space density rho(k) via three different methods: i) we reconstructed

M. I. Dyakonov

The current state of the theory of the Fractional Quantum Hall Effect is critically analyzed, especially the generally accepted concept of composite fermions. It is argued that there is no sound theoretical foundation for this concept. A simple one-dimensional model is proposed, which presumably has an energy spectrum similar to that of the FQHE system.

T. Franosch, A. Latz, R. M. Pick

The constitutive equations for the orientational dynamics of a liquid formed of linear molecules are derived microscopically. The resulting generalised Langevin equations coincide with the phenomenological approach of Dreyfus et al. Formally exact expressions are given for the phenomenological coefficients and various constraints are shown to be consequences

R. M. Pick, T. Franosch, A. Latz, C. Dreyfus

We derive expressions for the intensity of the Brillouin polarized spectrum of a molecular liquid formed of axially symmetric molecules. These expressions take into account both the molecular dielectric anisotropy and the modulation of the local polarisability by density fluctuations. They also incorporate all the retardation effects which occur in such liqu

A. Aliano, G. Kaniadakis, E. Miraldi

In the present work we study the main physical properties of a gas of $κ$-deformed bosons described through the statistical distribution function $f_κ=Z^{-1}[\exp_κ(β({1/2}m v^2-μ))-1]^{-1}$. The deformed $κ$-exponential $\exp_κ(x)$, recently proposed in Ref. [G.Kaniadakis, Physica A {\bf 296}, 405, (2001)], reduces to the standard exponential as the deforma

F. van Wijland

We consider systems whose steady-states exhibit a nonequilibrium phase transition from an active state to one -among an infinite number- absorbing state, as some control parameter is varied across a threshold value. The pair contact process, stochastic fixed-energy sandpiles, activated random walks and many other cellular automata or reaction-diffusion proce

Gernot Münster, Sergei B. Rutkevich

In many systems in condensed matter physics and quantum field theory, first order phase transitions are initiated by the nucleation of bubbles of the stable phase. In homogeneous nucleation theory the nucleation rate $Γ$ can be written in the form of the Arrhenius law: $Γ=\mathcal{A} e^{-\mathcal{H}_{c}}$. Here $\mathcal{H}_{c}$ is the energy of the critical

S. Jemima Balaselvi, A. Bharathi, V. Sankara Sastry, G. L. N. Reddy

The variation of TC in MgB2 has been systematically investigated for monovalent cation substitution in Mg1-xLixB2 and in Mg1-xCuxB2 and simultaneous cation and Carbon substitution in Mg0.80Li0.20B2-xCx and Mg0.95Cu0.05B2-xCx using dc resistivity and ac susceptibility techniques. TC seems to be uniquely determined by the electron count in the sample, being co

F. Dubin

The excitonic luminescence of an isolated polydiacetylene polymer chain in its monomer matrix is studied by micro-photoluminescence. These chains behave as perfect 1D excitonic systems with the expected 1/sqrt{E} density of states between 5 and 50 K. The temperature dependence of the homogeneous width is quantitatively explained by interaction with longitudi

V. D. Krevchik, A. B. Grunin, A. K. Aringazin, M. B. Semenov

The impurity photonic drag effect (PDE), theory for semiconductive quantum wire (QW) in a longitudinal (along the quantum wire axis) magnetic field B, has been developed. The PDE is due to the photon longitudinal momentum transmission to localized electrons, under optical transitions from D(-)-states to QW hybrid-quantum states, if the QW is described by the

M. Biasini, G. Ferro, G. Kontrym-Sznajd, A. Czopnik

A three dimensional mapping of the Fermi Surface (FS) of the rare-earth compound ErGa3 was determined via measurements of the angular correlation of the electron-positron annihilation radiation. The topology of the electronlike FS does show nesting properties which are consistent with the modulated antiferromagnetic structure of the system. We determine the

S. L. Narasimhan, P. S. R. Krishna, A. K. Rajarajan, K. P. N. Murthy

We show that the compact self avoiding walk configurations, kinetically generated by the recently introduced Interacting Growth Walk (IGW) model, can be considered as members of a canonical ensemble if they are assigned random values of energy. Such a mapping is necessary for studying the thermodynamic behaviour of this system. We have presented the specific

J. R. Thorstensen, W. H. Fenton

We give mean spectra and report orbital periods Porb based on radial velocities taken near minimum light for five dwarf novae, all of which prove to have Porb less than 2 hr. The stars and their periods are KX Aql, 0.06035(3) d; FT Cam, 0.07492(8) d; PU CMa, 0.05669(4) d; V660 Her, 0.07826(8) d;, and DM Lyr, 0.06546(6). The emission lines in KX Aql are notab

M. G. Richer, G. H. Tovmassian, G. Stasinska, R. F. Jameson

We present extensive new spectroscopy and imaging of PN G 135.9+55.9. We use these data as constraints to photoionization models to derive limits on the oxygen abundance. We find that PN G 135.9+55.9 has an oxygen abundance less than 1/50 of the solar value. Our models favour a value of 12 + \log O/H between 5.8 and 6.5 dex, confirming that PN G 135.9+55.9 i

E. Bertone, A. Buzzoni, L. H. Rodriguez-Merino, M. Chavez

We present an extended theoretical library of over 800 synthetic stellar spectra, covering energy distribution in the optical range (lambda = 3500-7000 angstrom), at inverse resolution R=500000. The library, based on the ATLAS9 model atmospheres, has been computed with the SYNTHE code developed by R.L. Kurucz. The grid spans a large volume in the fundamental

C. M. Dutra, B. X. Santiago, E. L. D. Bica, B. Barbuy

We extract J and K_s magnitudes from the 2MASS Point Source Catalog for approximately 6 million stars with 8 < K_s < 13 in order to build an A_K extinction map within 10 degrees of the Galactic centre. The extinction was determined by fitting the upper giant branch of (K_s, J-K_s) colour-magnitude diagrams to a dereddened upper giant branch mean locus built

K. Mukai, W. D. Pence, S. L. Snowden, K. D. Kuntz

X-ray binaries in the Milky Way are among the brightest objects on the X-ray sky. With the increasing sensitivity of recent missions, it is now possible to study X-ray binaries in nearby galaxies. We present data on six luminous sources in the nearby spiral galaxy, M101, obtained with the Chandra ACIS-S. Of these, five appear to be similar to ultraluminous s

Russel White, Gibor Basri

We present high resolution optical spectra obtained with the HIRES spectrograph on the Keck I telescope of low mass T Tauri stars and brown dwarfs (LMTTs) in Taurus-Auriga. Of particular interest is the previously classified &#34;continuum T Tauri star&#34; GM Tau, which has a spectral type of M6.5 and a mass just below the stellar/substellar boundary. None

D. Homeier, P. H. Hauschildt, F. Allard

We present the current status of PHOENIX model atmospheres for dwarfs of the spectral type T, typical for older field brown dwarfs and low-mass brown dwarfs. The results are based on new predictions of the CH_4 line opacities from theoretical calculations with the STDS software package, extrapolating to transitions from rotational levels up to J=40. While in

Bing Zhang

Pulsar radio emission is believed to be originated from the electron-positron pairs streaming out from the polar cap region. Pair formation, an essential condition for pulsar radio emission, is believed to be sustained in active pulsars via one photon process from either the curvature radiation (CR) or the inverse Compton scattering (ICS) seed photons, or so

C. Barbachoux, G. Le Denmat

We investigate the temporal evolution of the redshift and the luminosity distance within the standard Friedmann-Roberston-Walker cosmological model. The redshift and luminosity distance of sources evolve with time and we show that they tend to given values, namely the stable equilibrium states associated to the first order differential equation they verify.

B. Fuchs

An update of the set of low surface brightness galaxies is presented which can be used to set constraints on the otherwise ambiguous decompositions of their rotation curves into contributions due to the various components of the galaxies. The selected galaxies show all clear spiral structure and arguments of density wave theory of galactic spiral arms are us

G. Lamer, I. M. McHardy, P. Uttley, K. Jahoda

We report on the X-ray spectral variability of the Seyfert 1 galaxy NGC 4051 observed with the Rossi X-ray Timing Explorer (RXTE) during a 1000 day period between May 1996 and March 1999. The spectra were obtained as part of monitoring observations and from two long observations using the RXTE Proportional Counter Array (PCA). During the monitoring period th

Edwin A. Bergin, Michael J. Kaufman, Gary J. Melnick, Ronald L. Snell

Using NASA&#39;s Submillimeter Wave Astronomy Satellite (SWAS) we have examined the production of water in quiescent and shocked molecular gas through a survey of the 556.936 GHz transition of ortho-H2O in the NGC 1333 molecular core. These observations reveal broad emission lines associated with the IRAS~2, IRAS~4, IRAS~7, and HH7-11 outflows. Towards 3 pos

S. T. Maddison, R. J. Humble, J. R. Murray

We have developed a new numerical technique for simulating dusty-gas flows. Our unique code incorporates gas hydrodynamics, self-gravity and dust drag to follow the dynamical evolution of a dusty-gas medium. We have incorporated several descriptions for the drag between gas and dust phases and can model flows with submillimetre, centimetre and metre size &#3

Fernando Santoro, Peter A. Thomas

We use the block model to generate merger trees for the first star clusters in a LCDM cosmology. Using a simple collapse model and cooling criterion, we determine which halos are able to form stars before being disrupted by mergers. We contrast the mass functions of all the resulting star clusters and those of primordial composition, i.e. star clusters that

W. K. M. Rice, P. J. Armitage, M. R. Bate, I. A. Bonnell

We use high resolution numerical simulations to study whether gravitational instabilities within circumstellar discs can produce astrometrically detectable motion of the central star. For discs with masses of M_disc = 0.1 M_star, which are permanantly stable against fragmentation, we find that the magnitude of the astrometric signal depends upon the efficien

F. De Paolis, G. Ingrosso, A. A. Nucita, A. Qadir

In a recent paper [Ruffa] it was proposed that the massive black hole at the Galactic center may act as a gravitational lens focusing gravitational wave energy to the Earth. Considering the gravitational wave signal emitted by galactic spinning pulsars, an enhancement in the gravitational wave intensity by a factor of a few thousand is found. For galactic an

M. Cervino, M. Molla

We examine the impact of discrete numbers of stars in stellar populations on the results of Chemical Evolution Models. We explore the resulting dispersion in the true yields and their possible relation with the dispersion in observational data based on a Simple Closed-Box model. In this framework we find that the dispersion is larger for the less evolved or

K. O. Mason, G. Branduardi-Raymont, P. M. Ogle, M. J. Page

Competing models for broad spectral features in the soft X-ray spectrum of the Seyfert I galaxy Mrk766 are tested against data from a 130 ks XMM-Newton observation. A model including relativistically broadened Ly-alpha emission lines of OVIII, NVII and CVI is a better fit to 0.3-2 keV XMM RGS data than a dusty warm absorber. Moreover, the measured depth of n

Ralph Neuhaeuser, Eike Guenther, Markus Mugrauer, Thomas Ott

We present JHK images of the young (~20 Myrs) nearby (~48 pc) stars HD 199143 and HD 358623 to search for (sub-)stellar companions around them. The images were obtained in JHK with the speckle camera SHARP-I in July 2001 and in H with SofI in Dec 2000, July 2001, and Dec 2001, all at the ESO 3.5m NTT. We present a companion candidate with a 2 arc sec offset

Guidetta Torricelli-Ciamponi, Paola Pietrini

In Active Galactic Nuclei (AGNs) the presence of a star cluster around the central black hole can have several effects on the dynamics and the emission of the global system. In this paper we analyze the interaction of stellar atmospheres with a wind outflowing from the central region of the AGN nucleus. Even a small mass loss from stars, as well as possible

Ryo Nagata, Takeshi Chiba, Naoshi Sugiyama

Evolution of primordial fluctuations in a Brans-Dicke type scalar-tensor gravity theory is comprehensively investigated. The harmonic attractor model, in which the scalar field has its harmonic effective potential in the Einstein conformal frame and the theory relaxes toward Einstein gravity with time, is considered. The evolution of adiabatic initial pertur

Noam Soker, Joel H. Kastner

We examine mechanisms that may explain the luminosities and relatively low temperatures of extended X-ray emission in planetary nebulae. By building a simple flow structure for the wind from the central star during the proto, and early, planetary nebulae phase, we estimate the temperature of the X-ray emitting gas and its total X-ray luminosity. We conclude

Nicholas J. Rattenbury, Ian A. Bond, Jovan Skuljan, Phil Yock

Extra-solar planets can be efficiently detected in gravitational microlensing events of high magnification. High accuracy photometry is required over a short, well-defined time interval only, of order 10-30 hours. Most planets orbiting the lens star are evidenced by perturbations of the microlensing light curve in this time.

Craig J. Copi, Glenn D. Starkman

Improving angular resolution is one of X-ray astronomy&#39;s big challenges. While X-ray interferometry should eventually vastly improve broad-band angular resolution, in the near-term, X-ray telescopes will sacrifice angular resolution for increased collecting area and energy resolution. Natural occultations have long been used to study sources on small ang

R. F. Butler, A. Golden, A. Shearer, C. Gouiffes

There remain several definitive gamma-ray pulsars that are as yet undetected in the optical regime. A classic case is the pulsar PSR B1951+32, associated with the complex CTB 80 SNR. Previous ground based high speed 2-d optical studies have ruled out candidates to m_V ~ 24. Hester (2000) has reported an analysis of archival HST/WFPC2 observations of the CTB

N. Alonso-Alberca, E. Lozano-Tellechea, T. Ortin

We show that the spacetime of the near-horizon limit of the extreme rotating d=5 black hole, which is maximally supersymmetric in N=2,d=5 supergravity for any value of the rotation parameter j in [-1,1], is locally isomorphic to a homogeneous non-symmetric spacetime corresponding to an element of the 1-parameter family of coset spaces SO(2,1)x SO(3)/SO(2)_j

T. R. Kirkpatrick, D. Belitz

A comprehensive theory of the quantum phase transition in clean, itinerant Heisenberg ferromagnets is presented. It is shown that the standard mean-field description of the transition is invalid in spatial dimensions $d\leq 3$ due to the existence of soft particle-hole excitations that couple to the order parameter fluctuations and lead to an upper critical

Mohammad R. Garousi

We evaluate various disk level four-point functions involving the massless scalar and tachyon vertex operators in the presence of background B-flux in superstring theory. By studying these amplitudes in specific limits, we find couplings of two scalars with two tachyons, and couplings of four tachyons on the world-volume of non-BPS D-branes of superstring th

Yasuhiro Utsumi, Hiroshi Imamura, Masahiko Hayashi, Hiromichi Ebisawa

By using the drone-fermion representation and the Schwinger-Keldysh approach, we calculate the current noise and the charge noise for a single-electron transistor in the non-equilibrium state in the presence of large quantum fluctuation of island charge. Our result interpolates between those of the &#34;orthodox theory&#34; and the &#34;co-tunneling theory&#

Masato Okado, Anne Schilling, Mark Shimozono

Kirillov and Reshetikhin conjectured what is now known as the fermionic formula for the decomposition of tensor products of certain finite dimensional modules over quantum affine algebras. This formula can also be extended to the case of $q$-deformations of tensor product multiplicities as recently conjectured by Hatayama et al. (math.QA/9812022 and math.QA/

E. L. Saldin, E. A. Schneidmiller, M. V. Yurkov

The paper describes a new concept of visible pump/X-ray probe/slow detector experiments that could be performed at third-generation synchrotron light sources. We propose a technique that would allow time resolution up to femtosecond capabilities to be recovered from a long (100 ps) X-ray probe pulse. The visible pump pulse must be as short as the desired tim

Daniel Dugger, Brooke Shipley

We show that if two rings have equivalent derived categories then they have the same algebraic K-theory. Similar results are given for G-theory, and for a large class of abelian categories.

Danny Calegari

This is a problem list in the theory of foliations and laminations of 3-manifolds. The focus is on the relationship of foliations and laminations with other aspects of 3-manifold topology, especially with the Thurston theory of geometric structures. This problem list is not meant to be comprehensive; rather it focusses on research areas that currently seem (

Steven Shin-Yi Lu

Given a compact complex manifold X of dimension n, we define a bimeromorphic invariant $κ_+(X)$ as the maximum p for which there is a saturated line subsheaf L of the sheaf of holomorphic p forms whose Kodaira dimension $κ(L)$ equals p. We call X special if $κ_+(X)=0$. We give some evidence that this condition characterizes X to have identically vanishing Ko

Yujiro Kawamata

Let $X$ and $Y$ be smooth projective varieties over $\mathbb{C}$. They are called {\it $D$-equivalent} if their derived categories of bounded complexes of coherent sheaves are equivalent as triangulated categories, while {\it $K$-equivalent} if they are birationally equivalent and the pull-backs of their canonical divisors to a common resolution coincide. We

Yuri G. Zarhin

Suppose K is a field of characteristic 0, $K_a$ is its algebraic closure, p is an odd prime. Suppose, $f(x) \in K[x]$ is a polynomial of degree $n \ge 5$ without multiple roots. Let us consider a curve $C: y^p=f(x)$ and its jacobian J(C). It is known that the ring End(J(C)) of all $K_a$-endomorphisms of J(C) contains the ring $Z[ζ_p]$ of integers in the pth

Carlos Castro

We present a new physical model that links the maximum speed of light with the minimal Planck scale into a maximal-acceleration Relativity principle in the spacetime tangent bundle and in phase spaces (cotangent bundle). Crucial in order to establish this link is the use of Clifford algebras in phase spaces. The maximal proper-acceleration bound is a = c^2/

M. Awramik, M. Czakon, A. Onishchenko, O. Veretin

The details of the recent calculation of the two-loop bosonic corrections to the muon lifetime in the Standard Model are presented. The matching on the Fermi theory is discussed. Renormalisation in the on-shell and in the MS scheme is studied and transition between the schemes is shown to lead to identical results. High precision numerical methods are compar

H. Matsufuru, J. Harada, T. Onogi, A. Sugita

We examine whether the $O(a)$ improved quark action on anisotropic lattices can be used as a framework for the heavy quark, which enables precision computation of matrix elements of heavy-light mesons. To this end, it is crucial to verify that a mass independent and nonperturbative tuning of the parameters is possible. As a first step, we observe the dispers

T. Mishonov, S. -L. Drechsler, E. Penev

Within the weak-coupling BCS scheme we derive a general form of the coefficients in the Ginzburg-Landau expansion of the free energy of a superconductor for the case of a Fermi level close to a van Hove singularity (VHS). A simple expression for the influence of the VHS on the specific heat jump is then obtained for the case where gaps for different bands ar

R. A. Roemer, A. MacKinnon, C. Villagonzalo

The electronic properties of disordered systems have been the subject of intense study for several decades. Thermoelectric properties, such as thermopower and thermal conductivity, have been relatively neglected. A long standing problem is represented by the sign of the thermoelectric power. In crystalline semiconductors this is related to the sign of the ma

Alexander Moroz

It is shown that small inclusions of a low absorbing metal can have a dramatic effect on the photonic band structure. In the case of diamond and zinc-blende photonic crystals, several complete photonic band gaps (CPBG&#39;s) can open in the spectrum, between the 2nd-3rd, 5th-6th, and 8th-9th bands. Unlike in the purely dielectric case, in the presence of sma

C. Tsallis, A. Rapisarda, V. Latora, F. Baldovin

We present a brief pedagogical guided tour of the most recent applications of nextensive statistical mechanics to well defined nonlinear dynamical systems, ranging from one-dimensional dissipative maps to many-body Hamiltonian systems.

John F. Beacom

A long-standing problem in supernova physics is how to measure the total energy and temperature of $ν_μ$, $ν_τ$, $\barν_μ$, and $\barν_τ$. While of the highest importance, this is very difficult because these flavors only have neutral-current detector interactions. We propose that neutrino-proton elastic scattering, $ν+ p \to ν+ p$, can be used for the detec

G. Paesold, R. Kallenbach, A. O. Benz

A new mechanism for acceleration and enrichment of 3He during impulsive solar flares is presented. Low-frequency electromagnetic plasma waves excited by the Electron Firehose Instability (EFI) can account for the acceleration of ions up to 1 MeV/amu energies as a single stage process. The EFI arises as a direct consequence of the free energy stored in a temp

H. M. Antia, S. M. Chitre

Primary inversions of accurately measured solar oscillation frequencies coupled with the equations of thermal equilibrium and other input physics, enable us to infer the temperature and hydrogen abundance profiles inside the Sun. These profiles also help in setting constraints on the input physics as well as on heavy element abundance in the solar core. Usin

A. Omar, J. N. Chengalur, D. Anish Roshi

We present radio continuum images of three Galactic HII regions, S 201, S 206, and S 209 near 232, 327, and 610 MHz using the Giant Meterwave Radio Telescope (GMRT). The GMRT has a mix of short and long baselines, therefore, even though the data have high spatial resolution, the maps are still sensitive to diffuse extended emission. We find that all three HI

W. C. Jones, R. S. Bhatia, J. J. Bock, A. E. Lange

We have developed a bolometric detector that is intrinsically sensitive to linear polarization which is optimized for making measurements of the polarization of the cosmic microwave background radiation. The receiver consists of a pair of co-located silicon nitride micromesh absorbers which couple anisotropically to linearly polarized radiation through a cor

Arkadiusz Olech

This report analyzes the I-band CCD photometry of Nova V1974 Cygni from the 1997 observational season. The analysis shows that both short-term modulations with periods 0.0813 and 0.085 days are still present in the light curve of the star. We confirmed the stability of the shorter period which is interpreted as the orbital period of the binary system. Its va

Manfred Lindner

We discuss in detail different future long baseline neutrino oscillation setups and we show the remarkable potential for very precise measurements of mass splittings and mixing angles. Furthermore it will be possible to make precise tests of coherent forward scattering and MSW effects, which allow to determine the sign of $Δm^2$. Finally strong limits or mea

Jan Snellman

Newman, Schneider and Shalev defined the entropy of a graded associative algebra A as H(A) = \limsup_{n \to \infty} \sqrt[n]{a_n}, where a_n is the vector space dimension of the n&#39;th homogeneous component. When A is the homogeneous quotient of a finitely generated free associative algebra, they showed that H(A) \le \sqrt{a_2}. Using some results of Fried

Shin&#39;ichi Nojiri, Sergei D. Odintsov

Using graviton correlator on deSitter (dS) brane in 5d AdS or dS bulk we calculate the four-dimensional Newton potential. For flat brane in AdS bulk the Randall-Sundrum result is recovered. For flat brane in dS bulk the sign of subleading ($1/r^3$) term in Newton potential is negative if compare with AdS bulk. In accordance with dS/CFT correspondence this in

John Schliemann, J. Carlos Egues, Daniel Loss

We investigate the nu=1 quantum Hall ferromagnet in the presence of spin-orbit coupling of the Rashba or Dresselhaus type by means of Hartree-Fock-typed variational states. In the presence of Rashba (Dresselhaus) spin-orbit coupling the fully spin-polarized quantum Hall state is always unstable resulting in a reduction of the spin polarization if the product

Jacob Siehler

We consider the possibility of semisimple tensor categories whose fusion rule includes exactly one noninvertible simple object. Conditions are given for the existence or nonexistence of coherent associative structures for such fusion rules, and an explicit construction of matrix solutions to the pentagon equations in the cases where we establish existence. M

John W Barrett, Christopher M Steele

The stationary phase technique is used to calculate asymptotic formulae for SO(4) Relativistic Spin Networks. For the tetrahedral spin network this gives the square of the Ponzano-Regge asymptotic formula for the SU(2) 6j symbol. For the 4-simplex (10j-symbol) the asymptotic formula is compared with numerical calculations of the Spin Network evaluation. Fina

Alexei Vazquez, Yamir Moreno

The existence or not of a percolation threshold on power law correlated graphs is a fundamental question for which a general criterion is lacking. In this work we investigate the problems of site and bond percolation on graphs with degree correlations and their connection with spreading phenomena. We obtain some general expressions that allow the computation

Christopher Tuffley

Given a topological space X denote by exp_k(X) the space of non-empty subsets of X of size at most k, topologised as a quotient of X^k. This space may be regarded as a union over 0 < l < k+1 of configuration spaces of l distinct unordered points in X. In the special case X=S^1 we show that: (1) exp_k(S^1) has the homotopy type of an odd dimensional sphere of

J. S. Milne

We prove various characterizations of the period torsor of abelian varieties. This is the submitted version.

Shu-Ju Tu, Ephraim Fischbach

We present a new computational scheme, GRIP (Geometric Random Inner Products), for testing the quality of random number generators. The GRIP formalism utilizes geometric probability techniques to calculate the average scalar products of random vectors generated in geometric objects, such as circles and spheres. We show that these average scalar products defi

Nik Weaver

We initiate a mathematically rigorous study of Klein-Gordon position operators in single-particle relativistic quantum mechanics. Although not self-adjoint, these operators have real spectrum and enjoy a limited form of spectral decomposition. The associated C*-algebras are identifiable as crossed products. We also introduce a variety of non self-adjoint ope

Nik Weaver

We give a combinatorial form of the Kadison-Singer problem, a famous problem in C*-algebra. This combinatorial problem, which has several minor variations, is a discrepancy question about vectors in C^n. Some partial results can be easily deduced from known facts in discrepancy theory.

Andrei Cheshel, Sergei V. Ketov

The Becker-Becker-Strominger formula, describing the string world-sheet instanton corrections to the four-fermion correlator in the Calabi-Yau compactified type-IIA superstrings, is calculated in the special case of the Calabi-Yau threefold realized in the intersection of two Del Pezzo surfaces. We also derive the selection rules in the supersymmetric GUT of