May 2003 arXiv papers — page 12

Alexei Borodin, Grigori Olshanski

We study the asymptotics of certain measures on partitions (the so-called z-measures and their relatives) in two different regimes: near the diagonal of the corresponding Young diagram and in the intermediate zone between the diagonal and the edge of the Young diagram. We prove that in both cases the limit correlation functions have determinantal form with a

G. A. T. F. da Costa, J. Variane

In this paper, the results of part I regarding a special case of Feynman identity are extended. The sign rule for a path in terms of data encoded by its word and formulas for the numbers of distinct equivalence classes of nonperiodic paths of given length with positive or negative sign are obtained for this case. Also, a connection is found between these num

Benoit Cloitre, N. J. A. Sloane, Matthew J. Vandermast

Aronson's sequence 1, 4, 11, 16, ... is defined by the English sentence ``t is the first, fourth, eleventh, sixteenth, ... letter of this sentence.'' This paper introduces some numerical analogues, such as: a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition ``n is a member of the sequence

Shrawan Kumar

The aim of this paper is to put some recent results of Huang-Pandzic (conjectured by Vogan) and Kostant on Dirac cohomology in a broader perspective.This is achieved by introducing an induction functor in the noncommutative equivariant cohomology. In this context, the results of Huang-Pandzic and Kostant are interpreted as special cases (corresponding to the

G. Giachetta, L. Mangiarotti, G. Sardanashvily

Generalized symmetries and supersymmetries depending on derivatives of dynamic variables are treated in a most general setting. Studding cohomology of the variational bicomplex, we state the first variational formula and conservation laws for Lagrangian systems on fiber bundles and graded manifolds under generalized symmetries and supersymmetries of any orde

János Kollár

This note describes the subring of the Grothendieck ring of k-varieties generated by smooth conics; finding many zero divisors. The proof uses only elementary projective geometry.

Gergely Harcos

This thesis contributes to the analytic theory of automorphic L-functions. We prove an approximate functional equation for the central value of the L-series attached to an irreducible cuspidal automorphic representation of GL(m) over a number field. We investigate the decay rate of the cutoff function and its derivatives in terms of the analytic conductor in

Patrick Hummel

Issai Schur once asked if it was possible to determine a bound, preferably using elementary methods, such that for all prime numbers p greater than the bound, the greatest number of consecutive quadratic non-residues modulo p is always less than the square root of p. This paper uses elementary methods to prove that 13 is the only prime number for which the g

Eric Sommers

We determine which nilpotent orbits in $E_6$ have normal closure and which do not. We also verify a conjecture about small representations in rings of functions on nilpotent orbit covers for type $E_6$.

Djordje Minic, Chia-Hsiung Tze

We argue that the demand of background independence in a quantum theory of gravity calls for an extension of standard geometric quantum mechanics. We discuss a possible kinematical and dynamical generalization of the latter by way of a quantum covariance of the state space. Specifically, we apply our scheme to the problem of a background independent formulat

Rutger Boels, Jan de Boer, Robert Duivenvoorden, Jeroen Wijnhout

We continue our study of nonperturbative superpotentials of four-dimensional N=2 supersymmetric gauge theories with gauge group U(N) on R^3 x S^1, broken to N=1 due to a classical superpotential. In a previous paper, hep-th/0304061, we discussed how the low-energy quantum superpotential can be obtained by substituting the Lax matrix of the underlying integra

Cecilia Albertsson

This thesis first gives a background and review of the article hep-th/0102038, where we substantiated a conjectured duality between two a priori unrelated gauge theories, N=2 quiver theory and N=2 Seiberg-Witten theory. These gauge theories have different realisations as the worldvolume theories on different D-brane configurations. We showed that there is an

S. Hayakawa

We discuss a model in which the boundary condition decides the four dimensional cosmological constant. It is reviewed in a primitive way that boundary conditions are required by the action principle.

A. A. Reshetnyak

The basic theorem of the Lagrangian formulation for general superfield theory of fields (GSTF) is proved. The gauge transformations of general type (GTGT) and gauge algebra of generators of GTGT (GGTGT) as the consequences of the above theorem are studied. It is established the gauge algebra of GGTGT contains the one of generators of gauge transformations of

Zhang Hongsheng

We cautiously reanalyze some easily confused notions on particle horizon problem in this paper and then we give a new answer to the particle horizon problem. This answer is independent of physics plunging into Planck time.

Andrzej J. Buras, P. Q. Hung

A recent surge of interest in the {\em early} unification of quarks and leptons, has prompted us to revive a paper \cite{HBB} written twenty two years ago. We provided there a general discussion of quark-lepton unification characterized by the gauge group $G_{S} \otimes G_{W}$ with two couplings $g_S$ and $g_W$ and by the unification mass scales $10\tev-1000

Ioannis Giannakis, Hai-cang Ren

We apply the Ginzburg-Landau theory to the colour superconducting phase of a lump of dense quark matter. We calculate the surface energy of a domain wall separating the normal phase from the super phase with the bulk equilibrium maintained by a critical external magnetic field. Because of the symmetry of the problem, we are able to simplify the Ginzburg-Land

T. Binoth, G. Heinrich

In a recent paper we have presented an automated subtraction method for divergent multi-loop/leg integrals in dimensional regularisation which allows for their numerical evaluation, and applied it to diagrams with massless internal lines. Here we show how to extend this algorithm to Feynman diagrams with massive propagators and arbitrary propagator powers. A

Francesco Vissani, Mohan Narayan, Veniamin Berezinsky

We consider non-renormalizable 1/M_X interaction terms as a perturbation of the conventional neutrino mass matrix. Particular attention is given to the gravitational interaction with M_X=M_Pl. We find that for the degenerate neutrino mass spectrum, the considered perturbation generates a non-zero U(e3) which is within reach of the high performance neutrino f

R. B. Appleby, G. P. Salam

We discuss the theoretical treatment of non-global observables, those quantities that are sensitive only to radiation in a restricted region of phase space, and describe how large `non-global' logarithms arise when we veto the energy flowing into the restricted region. The phenomenological impact of non-global logarithms is then discussed, drawing on exa

P. A. M. Guichon, L. Mossé, M. Vanderhaeghen

Using a soft pion theorem based on chiral symmetry and a $Δ(1232)$ resonance model we propose an estimate for the production cross section of low energy pions in the deeply virtual Compton scattering (DVCS) process. In particular, we express the $e p \to e γπN$ processes in terms of generalized parton distributions. We provide estimates of the contamination

Y. L. Wu, Y. A. Yan, M. Zhong, Y. B. Zuo

The Heavy quark effective field theory (HQEFT) is revisited in a more intuitive way. It is shown that HQEFT is a consistent large component QCD of heavy quarks. In the non-relativistic limit, HQEFT recovers the non-relativistic QCD (NRQCD). The resulting new effects in the HQEFT of QCD are carefully reexamined. It is then natural to come to the comments on t

P. Aurenche, M. E. Carrington, N. Marchal

We compute the production rate of lepton pair by static photons at finite temperature at two-loop order. We treat the infrared region of the gluon phase space carefully by using a hard thermal loop gluon propagator. The result is free of infrared and collinear divergences and exhibits an enhancement which produces a result of order $\sim e^2 g^3$ instead of

V. Cirigliano

We discuss radiative corrections to K_{e3} and pi_{e3} decays within chiral perturbation theory with virtual photons and leptons. We then present the extraction of the CKM elements V_{us} and V_{ud} using the presently available experimental input. Finally, we discus the test of CKM unitarity based on the present independent knowledge of V_{ud} and V_{us}, a

Bruce Knuteson, Paul Padley

The massive data sets from today's particle physics experiments present a variety of challenges amenable to the tools developed by the statistics community. From the real-time decision of what subset of data to record on permanent storage, to the reduction of millions of channels of electronics to a few dozen high-level variables of primary interest, to

Marina Giunta

Gluon jets with a large gap in the rapidity distribution of particles within the jet are very sensitive to color reconnection effects. Gluon jets of this type, selected from hadronic Z0 decay events produced in e+e- annihilations at LEP, are used to test three QCD models which include a simulation of color reconnection: one in the Ariadne Monte Carlo, one in

F. Filthaut

The DO detector at FNAL has undergone a significant upgrade for its present Run II data taking period, allowing for a broad B physics programme. This report focuses on studies performed on a sample of approximately 75 thousand inclusive J/psi events. Preliminary results on mass and lifetime measurements and prospects for flavour tagging are presented.

Patrice Perez

Recent studies to finalize the systematic error estimates on the measurement of the mass of the W boson at LEP2 are reviewed. Results including a new preliminary value from Aleph are updated together with the world average which is now 80.426 +- 0.034GeV/c2. The updated electroweak fit gives a 95% C.L. upper limit on the mass of the Higgs boson of 211GeV/c2.

M. Z. Wang

Recent results of baryonic B decays from Belle are reported. This study is done by a 78 fb$^{-1}$ data sample, consisting of $85.0 \pm 0.5$ million $B\bar{B}$ pairs, collected by the Belle detector at the KEKB asymmetric energy $e^+e^-$ (3.5 on 8 GeV) collider. The results reported here include the first observation of the two-body decay $B^0 \to p\barΛ_c$,

Gautier Hamel De Monchenault

We review recent time-dependent measurements in the B meson sector based on data collected between 1999 and 2002 by the BABAR detector, which correspond to approximately 88 million BB pairs.

Thomas Thiemann

The Hamiltonian constraint remains the major unsolved problem in Loop Quantum Gravity (LQG). Seven years ago a mathematically consistent candidate Hamiltonian constraint has been proposed but there are still several unsettled questions which concern the algebra of commutators among smeared Hamiltonian constraints which must be faced in order to make progress

A. V. Minkevich

Problem of cosmological singularity of general relativity theory is discussed. The possible resolution of this problem in the framework of inflationary cosmology is proposed. Physical conditions leading to bouncing inflationary solutions in the frame of general relativity theory and gauge theories of gravitation are compared. It is shown that gauge theories

Nancy Hartline Bercich

Databases, collections of related data, are as old as the written word. A database can be anything from a homemaker's metal recipe file to a sophisticated data warehouse. Yet today, when we think of a database we invariably think of computerized data and their DBMSs (database management systems). How did we go from organizing our data in a simple metal f

A. A. Svidzinsky, S. T. Chui

We study the insulator-superfluid transition of spin-1 bosons in an optical lattice in a uniform magnetic field. Based on a mean-field approximation we obtained a zero-temperature phase diagram. We found that depending on the particle number the transition for bosons with antiferromagnetic interaction may occur into different superfluid phases with spins ali

Sumiyoshi Abe, Norikazu Suzuki

A part of the seismic time series, in which the Omori law for temporal pattern of aftershocks holds, is refereed to as the Omori regime. Here the properties of correlation between earthquake events both inside and outside of the Omori regime are studied by analysis of the data taken in southern California. It is found that inside of the Omori regime correlat

A. N. Gorban, A. A. Rossiev, D. C. Wunsch

A method of modeling data with gaps by a sequence of curves has been developed. The new method is a generalization of iterative construction of singular expansion of matrices with gaps. Under discussion are three versions of the method featuring clear physical interpretation: linear - modeling the data by a sequence of linear manifolds of small dimension; qu

Sadhan K. Adhikari

The stability of an attractive Bose-Einstein condensate on a joint one-dimensional optical lattice and an axially-symmetric harmonic trap is studied using the numerical solution of the time-dependent mean-field Gross-Pitaevskii equation and the critical number of atoms for a stable condensate is calculated. We also calculate this critical number of atoms in

Wei-Dong Li, Yunbo Zhang, J. -Q. Liang

The energy band structure and energy splitting due to quantum tunneling in two weakly linked Bose-Einstein condensates were calculated by using the instanton method. The intrinsic coherent properties of Bose Josephson junction were investigated in terms of energy splitting. For $E_{C}/E_{J}\ll 1$, the energy splitting is small and the system is globally phas

F. Mazzanti, A. Polls, A. Fabrocini

The energy and structure of dilute hard- and soft-sphere Bose gases are systematically studied in the framework of several many-body approaches, as the variational correlated theory, the Bogoliubov model and the uniform limit approximation, valid in the weak interaction regime. When possible, the results are compared with the exact diffusion Monte Carlo ones

Kwangsik Nho, Efstratios Manousakis

We study the specific heat scaling function of superfluids confined in cubic geometry and in parallel-plate (film) geometry with open boundary conditions (BC) along the finite dimensions using Monte Carlo simulation. For the case of cubic geometry for the superfluid order parameter we apply open BC in all three directions. We also calculated the specific hea

S. I. Matveenko, S. Brazovskii

For a one-dimensional electron-phonon system we consider the photon absorption involving electronic excitations within the pseudogap energy range. In the framework of the adiabatic approximation for the electron - phonon interactions these processes are described by nonlinear configurations of an instanton type. We calculate the subgap absorption as it can b

V. I. Yukalov, E. P. Yukalova, V. S. Bagnato

The resonant formation of nonlinear coherent modes in trapped Bose-Einstein condensates is studied. These modes represent nonground-state Bose condensates. The methods of describing the spectrum of the nonlinear modes are discussed. The latter can be created by modulating the trapping potential with a frequency tuned close to the transition frequency between

Claudia Sifel, Ulrich Hohenester

We propose a single-electron doped quantum dot in a field-effect structure as an optically triggered turnstile for spin-entangled electrons. A short laser pulse excites a charged exciton, whose quantum properties are transferred through tunneling and relaxation to the spin entanglement between electrons in the dot and contact. We identify the pertinent disen

Rochus Klesse, Florian Merz

We address the origin of the residual resistance observed in microwave irradiated two-dimensional electron gases in a weak magnetic field. We study charge modulations arising from negative photo-conductivity and show that dissipative currents are exponentially suppressed. Relating the exponent to the temperature dependence of microscopic parameters taken fro

Yunbo Zhang, Harri Mäkelä, Kalle-Antti Suominen

We investigate the topological defects in atomic spin-1 and spin-2 Bose-Einstein condensates by applying the homotopy group theory. With this rigorous approach we clarify the previously controversial identification of symmetry groups and order parameter spaces for the spin-1 case, and show that the spin-2 case provides a rare example of a physical system wit

A. S. Kirakosyan, V. L. Pokrovsky

Skyrmions in thin metallic ferromagnetic films are stable due to competition between the RKKY interaction and uniaxial magnetic anisotropy. We mimic the RKKY interaction by the next-nearest-neighbors ferromagnetic and antiferromagnetic exchange interactions. We demonstrate analytically and numerically dissipative transformation of a bubble created by a stron

C. Q. Wu, Y. Qiu, K. Nasu

By considering a metal/polymer/metal structure within a tight-binding one-dimensional model, we have investigated the polaron formation in the presence of an electric field. When a sufficient voltage bias is applied to one of the metal electrodes, an electron is injected into the polymer chain, then a self-trapped polaron is formed at a few hundreds of femto

Sergey Lee, Takahiko Masui, Ayako Yamamoto, Hiroshi Uchiyama

Carbon-substituted MgB2 single crystals, Mg(B_1-xC_x)_2 of 0.3-1.0 mm size were grown for x=0.02-0.15 by a high-pressure technique. The doping dependence of lattice constants studied in a range of x=0.0-0.2 shows a monotonic decrease in a, while the c parameter remains almost invariant. Using X-ray diffraction and Auger electron spectroscopy, the solubility

V. Ryzhii

We calculate the dissipative dc conductivity of a two-dimensional electron system in a magnetic field for the situation when its effective temperature exceeds the temperature of the acoustic phonon system. We demonstrate that at sufficiently large difference between the electron and lattice temperatures (sufficiently strong microwave radiation) the dissipati

O. Durán, R. Mulet

We study an evolutionary version of the spatial prisoner's dilemma game, where the agents are placed in a random graph. For lattices with fixed connectivity, $α$, we show that for low values of $α$ the final density of cooperating agents depends on the initial conditions, while it does not depend for high connectivity lattices. We fully characterized the

Ö. Legeza, J. Sólyom

In order to optimize the ordering of the lattice sites in the momentum space and quantum chemistry versions of the density matrix renormalization group (DMRG) method we have studied the separability and entanglement of the target state for the 1-D Hubbard model and various molecules. By analyzing the behavior of von Neumann and Neumann-Renyi entropies we hav

P. Sollich, M. R. Evans

We study the dynamics of the East model, comprising a chain of uncoupled spins in a downward-pointing field. Glassy effects arise at low temperatures $T$ from the kinetic constraint that spins can only flip if their left neighbour is up. We give details of our previous solution of the non-equilibrium coarsening dynamics after a quench to low $T$ (Phys. Rev.\

F. Krennrich, I. H. Bond, P. J. Boyle, S. M. Bradbury

Mrk 421 is the first TeV blazar found to exhibit significant spectral variability during strong flaring activity, showing hardening of the TeV spectrum in high emission states. Mrk 421 is also known to exhibit flux variability on time scales as short as 15 minutes. In this paper we present studies of hourly spectral variability of Mrk 421 in 2001 using data

F. Krennrich, E. Dwek

Energy spectra of gamma-ray blazars may contain an imprint from the cosmic infrared background radiation due to gamma-ray absorption (pair-production) by soft photons constituting the extragalactic background light (EBL). The signature of this imprint depends on the spectral shape of the EBL. In this work we correct the observed spectra of Mrk 421 and Mrk 50

Gilbert Holder, Abraham Loeb

Many of the most luminous extragalactic radio sources are located at the centers of X-ray clusters, and so their radiation must be scattered by the surrounding hot gas. We show that radio observations of the highly-polarized scattered radiation (which depends on the electron density distribution) in combination with the thermal Sunyaev-Zeldovich effect (whic

Carlo Baccigalupi

We review the present knowledge of the diffuse Galactic synchrotron emission in polarisation. At microwave frequencies, we assess the expected contamination to the CMB polarisation angular power spectrum, for $E$ and $B$ modes, as expected after the WMAP first year measurements.

Max Pettini, Piero Madau, Michael Bolte, Jason X. Prochaska

In order to search for metals in the Lyman alpha forest at redshifts z > 4, we have obtained spectra of high S/N and resolution of three QSOs at z > 5.4 discovered by the Sloan Digital Sky Survey. These data allow us to probe to metal enrichment of the intergalactic medium at early times with higher sensitivity than previous studies. We find 16 C IV absorpti

Felix J. Lockman

Observations with the Green Bank Telescope of 21cm HI emission from the high-velocity cloud Complex H suggest that it is interacting with the Milky Way. A model in which the cloud is a satellite of the Galaxy in an inclined, retrograde circular orbit reproduces both the cloud's average velocity and its velocity gradient with latitude. The model places Co

D. Donato, M. Gliozzi, R. M. Sambruna, J. E. Pesce

We present Chandra observations of the X-ray environment of a sample of 6 BL Lacertae objects. The improved sensitivity of the ACIS experiment allows us to separate the core X-ray emission from the contribution of diffuse emission from the host galaxy/cluster scales. Within the short (2-6 ks) ACIS exposures, we find evidence for diffuse X-ray emission in 3 s

W. R. Brown, C. Allende Prieto, T. C. Beers, R. Wilhelm

The Century Survey Galactic Halo Project is a photometric and spectroscopic survey from which we select relatively blue stars (V-R<0.30 mag) as probes of the Milky Way halo. The Survey strip spans the range of Galactic latitude 35<b<88 deg, allowing us to study the nature of populations of stars and their systematic motions as a function of Galactic latitude

W. H. T. Vlemmings, H. J. van Langevelde, P. J. Diamond, H. J. Habing

The main-line OH masers around 4 AGB stars have been observed with the NRAO Very Long Baseline Array (VLBA) at 8 epochs over a period of 2.5 years. Using a phase referencing technique, the position of the most compact maser spot of each star was monitored with respect to two extragalactic reference sources. For U Her and W Hya, we observe the most blue-shift

John Krizmanic, Pierre Sokolsky, Robert Streitmatter

The presence of clouds between an airshower and a space-based detector can dramatically alter the measured signal characteristics due to absorption and scattering of the photonic signals. Furthermore, knowledge of the cloud cover in the observed atmosphere is needed to determine the instantaneous aperture of such a detector. Before exploring the complex natu

Robert Braun, David Thilker, Rene Walterbos

We have used the Westerbork array to carry out an unbiased wide-field survey for HI emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km/s over 1800 deg^2 and between -1000 < V_Hel<+6500 km/s. The primary data consists of auto-correlation spectra with an effective angular resolution of 49&#39; FWHM. We detect

L. D. Matthews, Kenneth Wood

From the analysis of sensitive HI 21-cm line observations, we find evidence for vertically extended HI emission (|z|<~2.4 kpc) in the edge-on, low surface brightness spiral galaxy UGC7321. Three-dimensional modelling suggests that the HI disk of UGC7321 is both warped and flared, but that neither effect can fully reproduce the spatial distribution and kinema

J. Heidt, K. Jaeger, K. Nilsson, U. Hopp

We present high-resolution imaging and low-resolution spectroscopy of the BL Lac object PKS 0537-441 (z = 0.893) and its environment. The observations were designed to clarify, whether the properties of PKS 0537-441 are affected by gravitational microlensing, or whether PKS 0537-441 and its environment act as a lensing system itself. Our observations show th

Maria Teresa Crosta, Alberto Vecchiato, Fernando de Felice, Mario G. Lattanzi

In this article we outline the structure of a general relativistic astrometric model which has been developed to deduce the position and proper motion of stars from 1-microarcsecond optical observations made by an astrometric satellite orbiting around the Sun. The basic assumption of our model is that the Solar System is the only source of gravity, hence we

R. Bandiera, F. Bocchino

The emission of the plerion G21.5-0.9 appears more extended in X rays than in radio. This is an unexpected result because it would imply that short-lived X-ray electrons may reach distances even larger than radio electrons. Applying an empirical relationship between dust scattering optical depth and photoelectric column density, the measured column density l

V. Joergens, M. Fernandez, J. M. Carpenter, R. Neuhäuser

We have studied the photometric variability of very young brown dwarfs and very low-mass stars (masses well below 0.2 M_sun) in the ChaI star forming region. We have determined photometric periods in the Gunn i and R band for the three M6.5-M7 type brown dwarf candidates ChaHa2, ChaHa3 and ChaHa6 of 2.2 to 3.4 days. These are the longest photometric periods

Aa. Sandqvist, P. Bergman, J. Black

The Odin satellite has been used to detect emission and absorption in the 557-GHz H2O line in the Galactic Centre towards the Sgr A* Circumnuclear Disk (CND), and the Sgr A +20 km/s and +50 km/s molecular clouds. Strong broad H2O emission lines have been detected in all three objects. Narrow H2O absorption lines are present at all three positions and origina

Paola Sestito, Sofia Randich, Jean-Claude Mermilliod, Roberto Pallavicini

We have carried out a high resolution spectroscopic survey of the 220-250 Myr old cluster NGC 6475: our main purpose is to investigate Li evolution during the early stages of the Main Sequence. We have determined Li abundances for 33 late F to K-type X-ray selected cluster candidates, extending the samples already available in the literature; for part of the

Stefan Gottloeber, Ewa Lokas, Anatoly Klypin, Yehuda Hoffman

Using high resolution N-body simulations we address the problem of emptiness of giant 20 Mpc/h diameter voids found in the distribution of bright galaxies. Are the voids filled by dwarf galaxies? Do cosmological models predict too many small dark matter haloes inside the voids? Can the problems of cosmological models on small scales be addressed by studying

M. Douspis, A. Riazuelo, Y. Zolnierowski, A. Blanchard

We review the cosmological constraints put by the current CMB experiment including the recent ARCHEOPS data, in the framework of Lambda-CDM and quintessence paradigm. We show that well chosen combinations of constraints from different cosmological observations lead to precise measurements of cosmological parameters. The Universe seems flat with a 70 percents

A. Majczyna, J. Madej, P. C. Joss A. Różańska

We present model atmospheres and theoretical spectra for X-ray bursters. Our models include the effects of Compton scattering on free electrons. The atmospheres have compositions that are mixtures of hydrogen, helium, and iron. For our models the ratio of color temperature, $T_c$, to effective temperature, $T_{eff}$, is in the range 1.2 - 1.8. This ratio dep

Kazuhiro Yamamoto

Based on the covariant Wigner function approach we derive the quantum Boltzmann equation for fermions with flavor mixing in general curved spacetime. This work gives a rigorous theoretical framework to investigate the flavor oscillation phenomena taking the gravitational effect into account. It is shown that the Boltzmann equation of the lowest order of the

A. Filipcic, M. Horvat, D. Veberic, D. Zavrtanik

The fluorescence-detection techniques of cosmic-ray air-shower experiments require precise knowledge of atmospheric properties to reconstruct air-shower energies. Up to now, the atmosphere in desert-like areas was assumed to be stable enough so that occasional calibration of atmospheric attenuation would suffice to reconstruct shower profiles. However, serio

Riccardo Scarpa, Gianni Marconi, Roberto Gilmozzi

We have carried out a study of the velocity dispersion of the stars in the outskirts of the globular cluster Omega Centauri, finding that the velocity dispersion remains constant at large radii rather than decrease monotonically. The dispersion starts to be constant for an acceleration of gravity of a = 2.1e-8 cm/s/s. A similar result is obtained reanalyzing

Masahiro Takada, Takashi Hamana

The lensing magnification effect due to large-scale structure is statistically measurable by correlation of size fluctuations in distant galaxy images as well as by the QSO-galaxy cross-correlation. We use the halo model formulation of Takada & Jain (2003) to compute these magnification-induced correlations without employing the weak lensing approximation, m

J. M. Ramallo Lopez, M. Renteria, E. E. Miro, F. G. Requejo

Perturbed-angular correlation, x-ray absorption, and small-angle x-ray scattering spectroscopies were suitably combined to elucidate the local structure of highly diluted and dispersed InOx species confined in porous of ZSM5 zeolite. These novel approach allow us to determined the structure of extremely nanosized In-O species exchanged inside the 10-atom-rin

Akihiro Ishibashi, Hideo Kodama

We investigate the classical stability of the higher-dimensional Schwarzschild black holes against linear perturbations, in the framework of a gauge-invariant formalism for gravitational perturbations of maximally symmetric black holes, recently developed by the authors. The perturbations are classified into the tensor, vector, and scalar-type modes accordin

M. G. Vavilov, I. L. Aleiner

We derive the quantum Boltzmann equation for the two-dimensional electron gas in a magnetic field such that the filling factor $ν\gg 1$. This equation describes all of the effects of the external fields on the impurity collision integral including Shubnikov-de Haas oscillations, smooth part of the magnetoresistance, and non-linear transport. Furthemore, we o

Carsten Marr, Almut Beige, Gerhard Rempe

The main obstacle for coherent control of open quantum systems is decoherence due to different dissipation channels and the inability to precisely control experimental parameters. To overcome these problems we propose to use dissipation-assisted adiabatic passages. These are relatively fast processes where the presence of spontaneous decay rates corrects for

Alex Buchel, Leopoldo A. Pando Zayas

We study the supergravity dual to the confinement/deconfinement phase transition for the N=4 SU(N) SYM on R x S^3 with a chemical potential conjugate to a U(1)\subset SO(6)_R charge. The appropriate supergravity system is a single charge black hole in D=5 N=8 gauged supergravity. Application of the gauge/string theory holographic renormalization approach lea

D. Boyanovsky, H. J. de Vega

Direct photon production from a quark gluon plasma (QGP) in thermal equilibrium is studied directly in real time. In contrast to the usual S-matrix calculations, the real time approach is valid for a QGP that formed and reached LTE a short time after a collision and of finite lifetime ($\sim 10-20 \mathrm{fm}/c$ as expected at RHIC or LHC). We point out that

Marcus Berg, Michael Haack, Boris Kors

String compactifications with non-abelian gauge fields localized on D-branes, with background NSNS and RR 3-form fluxes, and with non-trivial warp factors, can naturally exist within T-dual versions of type I string theory. We develop a systematic procedure to construct the effective bosonic Lagrangian of type I T-dualized along a six-torus, including the co

M. Kenzelmann, Y. Chen, C. Broholm, D. H. Reich

Inelastic neutron scattering was used to measure the magnetic field dependence of spin excitations in the antiferromagnetic S=1/2 chain CuCl_2 2(dimethylsulfoxide) (CDC) in the presence of uniform and staggered fields. Dispersive bound states emerge from a zero-field two-spinon continuum with different finite energy minima at wave numbers q=pi and q_i approx

Marco Cavaglia, Saurya Das, Roy Maartens

The generalized uncertainty principle, motivated by string theory and non-commutative quantum mechanics, suggests significant modifications to the Hawking temperature and evaporation process of black holes. For extra-dimensional gravity with Planck scale O(TeV), this leads to important changes in the formation and detection of black holes at the the Large Ha

Axel Brandenburg, William H. Matthaeus

In helical hydromagnetic turbulence with an imposed magnetic field (which is constant in space and time) the magnetic helicity of the field within a periodic domain is no longer an invariant of the ideal equations. Alternatively, there is a generalized magnetic helicity that is an invariant of the ideal equations. It is shown that this quantity is not gauge

Neil R. Constable, Finn Larsen

We express all correlation functions in timelike boundary Liouville theory as unitary matrix integrals and develop efficient techniques to evaluate these integrals. We compute large classes of correlation functions explicitly, including an infinite number of terms in the boundary state of the rolling tachyon. The matrix integrals arising here also determine

Ruth Durrer, Philippe Kocian

In this letter we calculate the emission of gravity waves by the binary pulsar in the framework of five dimensional braneworlds. We consider only spacetimes with one compact extra-dimension. We show that the presence of additional degrees of freedom, especially the &#39;gravi-scalar&#39; leads to a modification of Einstein&#39;s quadrupole formula. We comput

David Bachman, Daryl Cooper, Matthew E. White

We show if M is a closed, connected, orientable, hyperbolic 3-manifold with Heegaard genus g then g >= 1/2 cosh(r) where r denotes the radius of any isometrically embedded ball in M. Assuming an unpublished result of Pitts and Rubinstein improves this to g >= 1/2 cosh(r) + 1/2. We also give an upper bound on the volume in terms of the flip distance of a Heeg

Jacques Soffer

For any inclusive reaction of the type $A_1({spin} 1/2)+ A_2({spin} 1/2) \to B + X$, we derive new positivity constraints on spin observables and study their implications for theoretical models in view, in particular, of accounting for future data from the polarized $pp$ collider at BNL-RHIC. We find that the single transverse spin asymmetry $A_N$ for severa

A. P. Kostyuk, W. Greiner

A recently published experimental dependence of the J/psi to Drell-Yan ratio on the measured, by a zero degree calorimeter, forward energy E_ZDC in Pb+Pb collisions at the CERN SPS is analyzed. Using a model-independent approach it is shown that the data are at variance with an earlier published experimental dependence of the same quantity on the transverse

Patricio Salgado, Fernando Izaurieta, Eduardo Rodriguez

A higher dimensional gravity invariant both under local Lorentz rotations and under local Anti de Sitter boosts is constructed. It is shown that such a construction is possible both when odd dimensions and when even dimensions are considered. It is also proved that such actions have the same coefficients as those obtained by Troncoso and Zanelli.

Jogesh C. Pati

Evidence in favor of supersymmetric grand unification including that based on the observed family multiplet-structure, gauge coupling unification, neutrino oscillations, baryogenesis, and certain intriguing features of quark-lepton masses and mixings is noted. It is argued that attempts to understand (a) the tiny neutrino masses (especially Delta m^2 (nu_2 -

Krzysztof A. Meissner, Marek Olechowski

We present explicit analytic form of general warped solutions of the string inspired dilaton gravity system with bulk cosmological constant in 5 dimensions. The general solution allows for either nonvanishing effective 4-dimensional cosmological constant or the nontrivial 4-dimensional dilaton but not both.

A. Gurevich, S. Patnaik, V. Braccini, K. H. Kim

We report a significant enhancement of the upper critical field $H_{c2}$ of different $MgB_2$ samples alloyed with nonmagnetic impurities. By studying films and bulk polycrystals with different resistivities $ρ$, we show a clear trend of $H_{c2}$ increase as $ρ$ increases. One particular high resistivity film had zero-temperature $H_{c2}(0)$ well above the $

Volker Braun

I determine the twisted K-theory of all compact simply connected simple Lie groups. The computation reduces via the Freed-Hopkins-Teleman theorem to the CFT prescription, and thus explains why it gives the correct result. Finally I analyze the exceptions noted by Bouwknegt et al.

E. W. Piotrowski, J. Sladkowski

We discuss the time evolution of quotation of stocks and commodities and show that they form an Ising chain. We show that transaction costs induce arbitrage risk that usually is neglected. The full analysis of the portfolio theory is computationally complex but the latest development in quantum computation theory suggests that such a task can be performed on

Marek Szydlowski, Adam Krawiec

We consider a Friedmann-Robertson-Walker cosmological model with some exotic perfect fluid with spin known as the Weyssenhoff fluid. The possibility that the dark energy may be described in part by the Weyssenhoff fluid is discussed. The observational constraint coming from supernovae type Ia observations is established. This result indicates that, whereas t

Pedro Luis del Angel, Stefan Müller-Stach

We develop a theory of differential equations associated to families of algebraic cycles in higher Chow groups (i.e., motivic cohomology groups). This formalism is related to inhomogeneous Picard--Fuchs type differential equations. For families of K3 surfaces the corresponding non-linear ODE turns out to be symilar to Chazy&#39;s equation.