October 2005 arXiv papers — page 5

L. Chekhov, J. E. Nelson, T. Regge

Using the Penner--Fock parameterization for Teichmuller spaces of Riemann surfaces with holes, we construct the string-like free-field representation of the Poisson and quantum algebras of geodesic functions in the continuous-genus limit. The mapping class group acts naturally in the obtained representation.

Manfred Droste

Causal sets are particular partially ordered sets which have been proposed as a basic model for discrete space-time in quantum gravity. We show that the class C of all countable past-finite causal sets contains a unique causal set (U,<) which is universal (i.e., any member of C can be embedded into (U,<)) and homogeneous (i.e., (U,<) has maximal degree of sy

S. Carneiro, A. E. Montenegro

We present some cosmological solutions of Brans-Dicke theory, characterized by a decaying vacuum energy density and by a constant relative matter density. With these features, they shed light on the cosmological constant problems, leading to a presently small vacuum term, and to a constant ratio between the vacuum and matter energy densities. By fixing the o

Xin-zhou Li, Dao-jun Liu

The property and gravitational field of global monopole of tachyon are investigated in a four dimensional static space-time. We give an exact solution of the tachyon field in the flat space-time background. Using the linearized approximation of gravity, we get the approximate solution of the metric. We also solve analytically the coupled Einstein and tachyon

Matteo Luca Ruggiero

In the context of the natural splitting, the standard relative dynamics can be expressed in terms of gravito-electromagnetic fields, which allow to formally introduce a gravito-magnetic Aharonov-Bohm effect. We showed elsewhere that this formal analogy can be used to derive the Sagnac effect in flat space-time as a gravito-magnetic Aharonov-Bohm effect. Here

Matteo Luca Ruggiero, Angelo Tartaglia

We study the pulsar timing, focusing on the time delay induced by the gravitational field of the binary systems. In particular, we study the gravito-magnetic correction to the Shapiro time delay in terms of Keplerian and post-Keplerian parameters, and we introduce a new post-Keplerian parameter which is related to the intrinsic angular momentum of the stars.

Cheng-Yi Sun, De-Hai Zhang

In this paper, it is shown that the relative entropy is an increasing function of time in both the linear regime and the non-linear regime during the large scale structure formation in cosmology.

L. Bertossi, L. Bravo, E. Franconi, A. Lopatenko

Consistent query answering is the problem of computing the answers from a database that are consistent with respect to certain integrity constraints that the database as a whole may fail to satisfy. Those answers are characterized as those that are invariant under minimal forms of restoring the consistency of the database. In this context, we study the probl

A. S. Nunez, R. A. Duine, A. H. MacDonald

Spintronics in ferromagnetic metals is built on a complementary set of phenomena in which magnetic configurations influence transport coefficients and transport currents alter magnetic configurations. In this Letter we propose that corresponding effects occur in circuits containing antiferromagnetic metals. The critical current for switching can be smaller i

Gilad Barak, Ron Lifshitz

We have developed a set of numerical tools for the quantitative analysis of defect dynamics in quasiperiodic structures. We have applied these tools to study dislocation motion in the dynamical equation of Lifshitz and Petrich [Phys. Rev. Lett. 79 (1997) 1261] whose steady state solutions include a quasiperiodic structure with dodecagonal symmetry. Arbitrary

J. M. Tranquada

Charge and spin stripe order is a type of electronic crystal observed in certain layered cuprates associated with high-temperature superconductivity. Quantum-disordered stripes could be relevant for understanding the superconductivity. Here I discuss recent experimental characterizations of the stripe-ordered state in La(1.875)Ba(0.125)CuO(4), and compare th

W. A. Al-Saidi, Henry Krakauer, Shiwei Zhang

Calculations of the binding energy of the transition metal oxide molecules TiO and MnO are presented, using a recently developed phaseless auxiliary field quantum Monte Carlo approach. This method maps the interacting many-body problem onto a linear combination of non-interacting problems by a complex Hubbard-Stratonovich transformation, and controls the pha

M. Baenninger, A. Ghosh, M. Pepper, H. E. Beere

We report the experimental realization of a correlated insulating phase in 2D GaAs/AlGaAs heterostructures at low electron densities in a limited window of background disorder. This has been achieved at mesoscopic length scales, where the insulating phase is characterized by a universal hopping transport mechanism. Transport in this regime is determined only

N. Drichko, M. Dressel, A. Greco, J. Merino

We interpret the optical spectra of $α$-(BEDT-TTF)$_2M$Hg(SCN)$_4$ (M=NH$_4$ and Rb) in terms of a 1/4 filled metallic system close to charge ordering and show that in the conductivity spectra of these compounds a fraction of the spectral weight is shifted from the Drude-peak to higher frequencies due to strong electronic correlations. Analyzing the temperat

G. D. Fuchs, J. A. Katine, S. I. Kiselev, D. Mauri

We examine the spin torque (ST) response of magnetic tunnel junctions (MTJs) with ultra-thin MgO tunnel barrier layers to investigate the relationship between the spin-transfer torque and the tunnel magnetoresistance (TMR) under finite bias. We find that the spin torque per unit current exerted on the free layer decreases by less than 10% over a bias range w

Sylvain Capponi

We demonstrate the utility of effective Hamilonians for studying strongly correlated systems, such as quantum spin systems. After defining local relevant degrees of freedom, the numerical Contractor Renormalization (CORE) method is applied in two steps: (i) building an effective Hamiltonian with longer ranged interactions up to a certain cut-off using the CO

L. A. Falkovsky, E. G. Mishchenko

We consider theoretically a superlattice formed by thin conducting layers separated spatially between insulating layers. The dispersion of two coupled phonon-plasmon modes of the system is analyzed by using Maxwell&#39;s equations, with the influence of retardation included. Both transmission for the finite plate as well as absorption for the semi-infinite s

Y. Fujioka, J. Frantti, E. Yasuda, Y. Tanabe

Raman scattering data were collected on graphite monochromator. Spectra were interpreted in terms of the space group $P6_3mc$, a subgroup of space group $P6_3/mmc$. The latter has commonly been used for the interpretation of Raman scattering data. Space group $P6_3mc$ corresponds to the buckling of graphene sheets and is consistent with many spectral feature

S. S. Rao, Subhasis Sarangi, G. Venkataiah, Venu Gopala Reddy

Nd_0.67Sr_0.33MnO_3 nanoparticles with the grain size of about 30 nm are prepared by sol-gel method.These nanopowders are annealed at four different temperatures viz. 800 oC, 900 oC, 1000 oC and 1100 oC to study the effect of particle size on magnetic, transport and electron magnetic resonance (EMR) spectral parameters. The samples are characterized by XRD,

T. Stopa, B. Szafran, M. B. Tavernier, F. M. Peeters

The internal structure of a composite fermion is investigated for a two dimensional parabolic quantum dot containing three electrons. A Yukawa screened Coulomb interaction is assumed, which allows us to discuss the evolution of the electron-vortex correlations from the Coulomb interaction limit to the contact potential limit. The vortex structure approaches

A. Pimenov, P. P. Przyslupski, B. Dabrowski, A. Loidl

Negative refraction, which reverses many fundamental aspects of classical optics, can be obtained in systems with negative magnetic permeability and negative dielectric permittivity. This Letter documents an experimental realization of negative refraction at millimeter waves, finite magnetic fields and cryogenic temperatures utilizing a multilayer stack of f

G. Goev, V. Masheva, J. Geshev, M. Mikhov

A method for estimation of reversible and irreversible susceptibilities of initial magnetization curves has been developed. It deals only with the energy necessary for magnetizing and demagnetizing the sample, not with the nature of the magnetization processes neither with a specific type of anisotropy, so it could be applied for a wide variety of real mater

L. Brizhik, A. Eremko, B. Piette, M. Watson

We study here polaron (soliton) states of electrons or holes in a model describing carbon-type nanotubes. In the Hamiltonian of the system we take into account the electron-phonon interaction that arises from the deformation dependencies of both the on-site and the hopping interaction energies. Using an adiabatic approximation, we derive the equations for se

Denis Bartolo, Farid Bouamrirene, Emilie Verneuil, Axel Buguin

When a liquid drops impinges a hydrophobic rough surface it can either bounce off the surface (fakir droplets) or be impaled and strongly stuck on it (Wenzel droplets). The analysis of drop impact and quasi static &#39;&#39;loading&#39;&#39; experiments on model microfabricated surfaces allows to clearly identify the forces hindering the impalement transitio

A. D. Thakur, S. S. Banerjee, M. J. Higgins, S. Ramakrishnan

We explore the effect of varying drive on metastability features exhibited by the vortex matter in single crystals of 2H-NbSe$_2$ and CeRu$_2$ with varying degree of random pinning. An optimal balance between the pinning and driving force is needed to view the metastability effects in typically weakly pinned specimen of low temperature superconductors. As on

Dmitri V. Averin, Kristian Rabenstein, Vasili K. Semenov

We suggest a new type of the magnetic flux detector which can be optimized with respect to the measurement back-action, e.g. for the situation of quantum measurements. The detector is based on manipulation of ballistic motion of individual fluxons in a Josephson transmission line (JTL), with the output information contained in either probabilities of fluxon

H. Dery, L. Cywinski, L. J. Sham

A one dimensional theory of lateral spin-polarized transport is derived from the two dimensional flow in the vertical cross section of a stack of ferromagnetic and paramagnetic layers. This takes into account the influence of the lead on the lateral current underneath, in contrast to the conventional 1D modeling by the collinear configuration of lead/channel

J. Oitmaa, Weihong Zheng, D. Tompsett

We use high order linked cluster series to investigate the hard core boson model on the triangular lattice, at zero temperature. Our expansions, in powers of the hopping parameter $t$, probe the spatially ordered `solid&#39; phase and the transition to a uniform superfluid phase. At the commensurate fillings $n=1/3, 2/3$ we locate a quantum phase transition

Valentin S. Rychkov, M. L. Polianski, M. Buttiker

Motivated by a recent experiment by L.-H. Reydellet et al., Phys. Rev. Lett. 90, 176803 (2003), we discuss an interpretation of photon-assisted shot noise in mesoscopic multiprobe conductors in terms of electron-hole pair excitations. AC-voltages are applied to the contacts of the sample. Of interest are correlations resulting from the fact that electrons an

Philip J. Humphrey, David A. Buote, Fabio Gastaldello, Luca Zappacosta

Cosmological simulations of galaxy formation predict a universal form for the mass profile of dark matter (DM) halos from cluster to galaxy scales. Remarkably few interesting constraints exist, however, on DM halos in early-type galaxies. Using Chandra we present the temperature, density and mass profiles of a small sample of early-type galaxies, revealing s

D. Raimann, T. Storchi-Bergmann, H. Quintana, R. Hunstead

We investigate the nature of the continuum emission and stellar populations in the inner 1-3 kiloparsecs of a complete sample of twenty-four southern radio galaxies, and compare the results with a control sample of eighteen non-active early-type galaxies. Twelve of the radio galaxies are classified as Fanaroff-Riley type I (FRI), eight as FRII and four as in

Eunhyeuk Kim, Dong-Woo Kim, Giuseppina Fabbiano, Myung Gyoon Lee

We present a systematic study of the low mass X-ray binary (LMXB) populations of 6 elliptical galaxies. We utilize Chandra archival data to identify 665 X-ray point sources and HST archival data supplemented by ground observations to identify 6173 GCs. We associate 209 LMXBs with red GC (RGC) and 76 LMXBs with blue GCs (BGC), while we find no optical GC coun

E. M. Burbidge, G. Burbidge, H. C. Arp, W. M. Napier

It is shown that there are at least 21 QSOs within 1 degree of the nearby active spiral galaxy NGC3079. Many of them are bright (mag<18) so that the surface density of those closer than 15 arc minutes to the galaxy centre is close to 100 times the average in the field. The probability that this is an accidental configuration is shown to be less or equal to o

S. Foley, D. Watson, J. Gorosabel, J. P. U. Fynbo

We present spectroscopic observations of ESO 184-G82, the host galaxy of GRB980425/SN1998bw, and six galaxies in its field. A host redshift of z=0.0087+/-0.0006 is derived, consistent with that measured by Tinney et al. (1998). Redshifts are obtained for the six surrounding galaxies observed. Three of these galaxies lie within 11 Mpc of each other, confirmin

Sergiy Silich, Tatyana Lozinskaya, Alexei Moiseev, Nikolai Podorvanuk

We study the neutral hydrogen distribution and kinematics in the Local Group dwarf irregular galaxy IC 1613 and compare them with the ionized gas distribution and stellar content of the galaxy. We discuss several mechanisms which may be responsible for the origin of the observed complicated HI morphology and compare parameters of the most prominent kpc-scale

Jacek Niemiec, Michal Ostrowski

First-order Fermi acceleration processes at ultrarelativistic shocks are studied with Monte Carlo simulations. The accelerated particle spectra are derived by integrating the exact particle trajectories in a turbulent magnetic field near the shock. &#39;&#39;Realistic&#39;&#39; features of the field structure are included. We show that the main acceleration

KASCADE Collaboration, W. D. Apel

Lateral distributions for electrons and muons in extensive air showers measured with the array of the KASCADE experiment are compared to results of simulations based on the high-energy hadronic interaction models QGSJet and SIBYLL. It is shown, that the muon distributions are well described by both models. Deviations are found for the electromagnetic compone

Catherine Turon, Chris Done, Andreas Quirrenbach, Peter Schneider

As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly presented in connection with the four grand themes finally selected for the ESA Science Programme. They are placed in the context of the main discoveries of the past d

E. Athanassoula

From this vast subject, I will pick out and review three specific topics, namely the formation and evolution of bars, the formation of bulges, and the evolution during multiple major mergers. Bars form naturally in galactic discs. Their evolution is driven by the exchange of angular momentum within the galaxy. This is emitted mainly by near-resonant material

E. Athanassoula

The halo plays a crucial role in the evolution of barred galaxies. Its near-resonant material absorbs angular momentum emitted from some of the disc particles and helps the bar become stronger. As a result, a bar (oval) forms in the inner parts of the halo of strongly barred disc galaxies. It is thinner in the inner parts (but still considerably fatter than

A. Feldmeier, R. Nikutta

There is strong observational evidence of shocks and clumping in radiation-driven stellar winds from hot, luminous stars. The resulting non monotonic velocity law allows for radiative coupling between distant locations, which is so far not accounted for in hydrodynamic wind simulations. In the present paper, we determine the Sobolev source function and radia

Kanak Saha, Chanda J. Jog

The warps in many spiral galaxies are now known to asymmetric. Recent sensitive observations have revealed that asymmetry of warps may be the norm rather than exception. However there exists no generic mechanism to generate these asymmetries in warps. We have derived the dispersion relation in a compact form for the S-shaped warps(described by the m=1 mode)

Narae Hwang, Myung Gyoon Lee, Jong Chul Lee, Won-Kee Park

We report the discovery of three new star clusters in the halo of the Local Group dwarf irregular galaxy NGC 6822. These clusters were found in the deep images taken with the MegaPrime at the CFHT, covering a total field of 2 deg x 2 deg. The most remote cluster is found to be located as far as 79 arcmin away from the center of NGC 6822. This distance is sev

Myung Gyoon Lee, Narae Hwang

We present a discovery of a giant stellar halo in NGC 6822, a dwarf irregular galaxy in the Local Group. This halo is mostly made of old red giants, showing striking features: 1) it is several times larger than the main body of the galaxy seen in the optical images, and 2) it is elongated in the direction almost perpendicular to the HI disk of NGC 6822. The

Edward M. Cackett, Keith Horne

Emission-line regions in active galactic nuclei and other photoionized nebulae should become larger in size when the ionizing luminosity increases. This &#39;breathing&#39; effect is observed for the Hbeta emission in NGC 5548 by using Hbeta and optical continuum lightcurves from the 13-year 1989-2001 AGN Watch monitoring campaign. To model the breathing, we

S. Cecchini, E. Korolkova, A. Margiotta, L. Thompson

An evaluation of the background due to atmospheric muons in the ANTARES high energy neutrino telescope is presented. Two different codes for atmospheric shower simulation have been used. Results from comparisons between these codes at sea level and detector level are presented. The first results on the capability of ANTARES to reject this class of background

Olivier Mousis, Yann Alibert

We use the evolutionary turbulent model of Jupiter&#39;s subnebula described by Alibert et al. (2005a) to constrain the composition of ices incorporated in its regular icy satellites. We consider CO2, CO, CH4, N2, NH3, H2S, Ar, Kr, and Xe as the major volatile species existing in the gas-phase of the solar nebula. All these volatile species, except CO2 which

M. Krause, R. Wielebinski, M. Dumke

We observed the nearby early-type spiral galaxy NGC 4594 (M 104, Sombrero galaxy) with the Very Large Array at 4.86 GHz, with the Effelsberg 100-m telescope at 8.35 GHz as well as with the Heinrich Hertz Telescope at 345 GHz in radio continuum. The 4.86 and 8.35 GHz data contain polarization information and hence information about the magnetic fields: we det

S. Geier, U. Heber, N. Przybilla, R. P. Kudritzki

We present the analysis of 200 high-resolution and 150 low-resolution spectra of the pulsating subdwarf close binary KPD 1930+2752 obtained with the Keck and the Calar Alto 2.2 m telescopes. Using metal-rich, line blanketed LTE model atmospheres the atmospheric parameters T_{eff} = 35500 +/- 500 K, log g = 5.56 +/- 0.05 and log n(He)/n(H) = -1.48 +/- 0.02 we

E. W. Guenther, R. Neuhaeuser, G. Wuchterl, M. Mugrauer

Using NACO on the VLT in the imaging mode we have detected an object at a distance of only 0.7 arcsec from GQ Lup. The object turns out to be co-moving. We have taken two K-band spectra with a resolution of lambda /Delta lambda=700. In here, we analyze the spectra in detail. We show that the shape of spectrum is not spoiled by differences in the Strehl ratio

L. Foschini, G. Ghisellini, C. M. Raiteri, F. Tavecchio

Notwithstanding the big efforts devoted to the investigation of the mechanisms responsible for the high-energy (E>100 MeV) gamma-ray emission in active galactic nuclei (AGN), the definite answer is still missing. The X-ray energy band (0.4-10 keV) is crucial for this type of study, since both synchrotron and inverse Compton emission can contribute to the for

Tanja K. Nymark, Claes Fransson, Cecilia Kozma

The X-ray emission from the circumstellar interaction in Type II supernovae with a dense circumstellar medium is calculated. In Type IIL and Type IIn supernovae mass loss rates are generally high enough for the region behind the reverse shock to be radiative, producing strong radiation, particularly in X-rays. We present a model for the emission from the coo

Luke Barnes, Matthew J. Francis, Geraint F. Lewis, Eric V. Linder

Observational evidence indicating that the expansion of the universe is accelerating has surprised cosmologists in recent years. Cosmological models have sought to explain this acceleration by incorporating `dark energy&#39;, of which the traditional cosmological constant is just one possible candidate. Several cosmological models involving an evolving equat

R. G. Sharp, N. J. Reilly, S. H. Kable, T. W. Schmidt

We report high resolution (R~37,000) integral field spectroscopy of the central region (r<14arcsec) of the Red Rectangle nebula surrounding HD44179. The observations focus on the 5800A emission feature, the bluest of the yellow/red emission bands in the Red Rectangle. We propose that the emission feature, widely believed to be a molecular emission band, is n

F. Gastaldello, D. Buote, P. Humphrey, L. Zappacosta

The Chandra and XMM data for a sample of 19 relaxed groups/poor clusters, covering the temperature range 1-3 keV and selected to have the best available data, reveal a remarkable similarity in their temperature profile: cool cores outside of which the temperatures reach a peak for radii less than 0.1 of the virial radius and then decline. We fitted the deriv

Karl Glazebrook, Ivan Baldry, Warren Moos, Jeff Kruk

Wide-field imaging from space should not forget the dispersive dimension. We consider the capability of space-based imaging with a slitless grism: because of the low near-infrared background in space and the high sky-density of high redshift emission line galaxies this makes for a very powerful redshift machine with no moving parts. A small 1m space telescop

T. H. Jarrett, M. Polletta, I. P. Fournon, G. Stacey

We present ground-based optical and Spitzer infrared imaging observations of the interacting galaxy UGC 10214, the &#34;Tadpole Galaxy&#34; (z = 0.0310), focusing on the star formation activity in the nuclear, disk, spiral arms and tidal tail regions. The major findings of this study are that the Tadpole is actively forming stars in the main disk outside of

F. Yusef-Zadeh, H. Bushouse, C. D. Dowell, M. Wardle

(abridged) We describe highlights of the results of two observing campaigns in 2004 to investigate the correlation of flare activity in Sgr A* in different wavelength regimes, using a total of nine ground and space-based telescopes. We report the detection of several new near-IR flares during the campaign based on {\it HST} observations. The level of near-IR

Alexei O. Razoumov, Michael L. Norman, Jason X. Prochaska, Arthur M. Wolfe

We use high resolution Eulerian hydrodynamics simulations to study kinematic properties of the low ionization species in damped Ly-alpha systems at redshift z=3. Our adaptive mesh refinement simulations include most key ingredients relevant for modeling neutral gas in high-column density absorbers: hydrodynamics, gravitational collapse, continuum radiative t

J. Maíz Apellániz

I use HST spectrophotometry to analyze the calibration of 3 optical photometry systems: Tycho-2 B_T V_T, Strömgren u v b y, and Johnson U B V. For Tycho-2, I revisit the analysis of Maíz Apellániz (2005) to include the new recalibration of grating/aperture corrections, vignetting, and charge transfer inefficiency effects produced by the STIS group and to con

Christophe Hohlweg, Carsten Lange

We describe many different realizations with integer coordinates for the associahedron (i.e. the Stasheff polytope) and for the cyclohedron (i.e. the Bott-Taubes polytope) and compare them to the permutahedron of type A_n and B_n respectively. The coordinates are obtained by an algorithm which uses an oriented Coxeter graph of type A_n or B_n respectively as

M. A. L. Capri, D. Dudal, J. A. Gracey, V. E. R. Lemes

The nonlocal mass operator $Tr \int d^4x F_{μν} (D^2)^{-1} F_{μν}$ is considered in Yang-Mills theories in Euclidean space-time. It is shown that the operator $Tr \int d^4x F_{μν} (D^2)^{-1} F_{μν}$ can be cast in local form through the introduction of a set of additional fields. A local and polynomial action is thus identified. Its multiplicative renormaliz

David Blaschke, Dmitri N. Voskresensky, Hovik Grigorian

We show that within a recently developed nonlocal chiral quark model the critical density for a phase transition to color superconducting quark matter under neutron star conditions can be low enough for these phases to occur in compact star configurations with masses below 1.3 M_sun. We study the cooling of these objects in isolation for different values of

J. -S. Gagnon, F. Fillion-Gourdeau, S. Jeon

We use the full multiple scattering expansion of the retarded self-energy to obtain the gain and loss rates present in the Kadanoff-Baym relativistic transport equation. The rates we obtain include processes with any number of particles. As a first approximation, we only consider central cuts in the self-energies, but otherwise our results are general. We sp

Alexander L. Burin

Low-dimensional ordered arrays of optical elements can possess bound modes having an extremely high quality factor. Typically, these arrays consist of metal elements which have significantly high light absorption thus restricting performance. In this paper we address the following question: can bound modes be formed in dielectric systems where the absorption

Giacomo Cacciapaglia, Csaba Csaki, Seong Chan Park

Models of Gauge-Higgs unification in extra dimensions offer a very elegant playground where one can study electroweak symmetry breaking. The nicest feature is that gauge symmetry itself protects the Higgs potential from divergences, thus potentially curing the hierarchy problem in the Standard Model. In a flat space model tree-level contributions to electrow

Ariel Edery

The Casimir force due to {\it thermal} fluctuations (or pseudo-Casimir force) was previously calculated for the perfect Bose gas in the slab geometry for various boundary conditions. The Casimir pressure due to {\it quantum} fluctuations in a weakly-interacting dilute Bose-Einstein condensate (BEC) confined to a parallel plate geometry was recently calculate

D. F. Mundarain, J. Stephany

We discuss the appearance of Zeno (QZE) or anti-Zeno (QAE) effect in an exponentially decaying system. We consider the quantum dynamics of a continuously monitored two level system interacting with a squeezed bath. We find that the behavior of the system depends critically on the way in which the squeezed bath is prepared. For specific choices of the squeezi

T Oliynyk, V Suneeta, E Woolgar

We discuss certain recent mathematical advances, mainly due to Perelman, in the theory of Ricci flows and their relevance for renormalization group (RG) flows. We consider nonlinear sigma models with closed target manifolds supporting a Riemannian metric, dilaton, and 2-form B-field. By generalizing recent mathematical results to incorporate the B-field and

I. Cabrera-Carnero

The relation of the noncommutative self-dual Chern-Simons (NCSDCS) system to the noncommutative generalizations of Toda and of affine Toda field theories is investigated more deeply. This paper continues the programme initiated in $JHEP {\bf 10} (2005) 071$, where it was presented how it is possible to define Toda field theories through second order differen

K. A. Milton, I. Cavero-Pelaez, J. Wagner

Although Casimir, or quantum vacuum, forces between distinct bodies, or self-stresses of individual bodies, have been calculated by a variety of different methods since 1948, they have always been plagued by divergences. Some of these divergences are associated with the volume, and so may be more or less unambiguously removed, while other divergences are ass

Jian Wang, Quan Zhang, Chao-jing Tang

In this paper, we present an (n, n) threshold quantum secret sharing scheme of secure direct communication using Greenberger-Horne-Zeilinger state. The present scheme is efficient in that all the Greenberger-Horne-Zeilinger states used in the quantum secret sharing scheme are used to generate shared secret messages except those chosen for checking eavesdropp

An Min Wang

We propose and prove protocols of controlled and combined remote implementations of partially unknown quantum operations belonging to the restricted sets [An Min Wang: PRA, \textbf{74}, 032317(2006)] using GHZ states. We detailedly describe the protocols in the cases of one qubit, respectively, with one controller and with two senders. Then we extend the pro

An Min Wang

We propose and prove the protocol of remote implementations of partially unknown quantum operations of multiqubits belonging to the restricted sets. Moreover, we obtain the general and explicit forms of restricted sets and present evidence of their uniqueness and optimization. In addition, our protocol has universal recovery operations that can enhance the p

J. Campbell, R. K. Ellis, F. Maltoni, S. Willenbrock

We present a next-to-leading-order calculation of the production of a Z boson with two jets, one or more of which contains a heavy quark (Q=c,b). We show that the cross section with only one heavy-quark jet is larger than that with two heavy-quark jets at both the Fermilab Tevatron and the CERN LHC. These processes are the dominant irreducible backgrounds to

Serge Demers, Paolo Battinelli, William E. Kunkel

Star counts, obtained from a 2 x 2 degree area centered on NGC 6822 have revealed an optical image of this galaxy composed of two components: in addition to the well-known HI disk with its young stellar component, there is a spheroidal stellar structure as extensive as its HI disk but with its major axis at roughly right angles to it which we traced to at le

A. Alonso Izquierdo, W. Garcia Fuertes, M. de la Torre Mayado, J. Mateos Guilarte

A formula is derived that allows us to compute one-loop mass shifts for kinks and self-dual Abrikosov-Nielsen-Olesen vortices. The procedure is based in canonical quantization and heat kernel/zeta function regularization methods.

STAR Collaboration, R. L. Ray, M. Daugherity

Two-particle correlations and event-wise fluctuations in transverse momentum p_t are reported for Au-Au collisions at sqrt{s_{NN}} = 62 and 200 GeV on pseudorapidity (eta) and azimuth (phi). Distributions of all pairs of particles (no leading trigger particle) reveal jet-like correlations, or peaks at pair-wise opening angles of order 1 radian or less. The w

H. Mäkelä

In this paper we first derive a general method which enables one to create expressions for vortices and monopoles. By using this method we construct several order-parameters describing the vortices and monopoles of Bose-Einstein condensates with hyperfine spin F=1 and F=2. We concentrate on defects which are topologically stable in the absence of an external

Jérôme Dubois, Rinat Kashaev

In the asymptotic expansion of the hyperbolic specification of the colored Jones polynomial of torus knots, we identify different geometric contributions, in particular Chern--Simons invaraint and Reidemeister torsion.

D. L. Pagan, A. Shiryayev, T. P. Connor, J. D. Gunton

We report a numerical simulation for the phase diagram of a simple two dimensional model, similar to one proposed by Noro and Frenkel [J. Chem. Phys. \textbf{114}, 2477 (2001)] for membrane proteins, but one that includes the role of the solvent. We first use Gibbs ensemble Monte Caro simulations to determine the phase behavior of particles interacting via a

Leandro P. R. Pimentel

In this paper we study first-passge percolation models on Delaunay triangulations. We show a sufficient condition to ensure that the asymptotic value of the rescaled first-passage time, called the time constant, is strictly positive and derive some upper bounds for fluctuations. Our proofs are based on renormalization ideas and on the method of bounded incre

A. Marecki, P. Thomasson, K. -H. Mack, M. Kunert-Bajraszewska

Signatures of the re-occurrence of activity in radio-loud AGNs, indicated either by the so-called double-double or X-shaped structures, have been observed in a number of radio sources. All such objects known to date have linear sizes of the order of a megaparsec. A number of the sources that are appreciably more compact than this, but that exhibit hints of a

A. Cuoco, R. D&#39; Abrusco, G. Longo, G. Miele

Current experiments collecting high statistics in ultra-high energy cosmic rays (UHECRs) are opening a new window on the universe. In this work we discuss a large scale structure model for the UHECR origin which evaluates the expected anisotropy in the UHECR arrival distribution starting from a given astronomical catalogue of the local universe. The model ta

Igor I. Smolyaninov

Photoluminescence from a gold nanotip, which is induced by surface plasmons propagating over a curved tapered nanotip surface is considered in a co-moving accelerated reference frame. Similar to the surface-enhanced Raman scattering (SERS) effect, nonlinear optical mixing of the surface plasmons with the Unruh quanta is supposed to be enhanced by many orders

A. Shalchi

Current spacecraft missions such as Wind and ACE can be used to determine magnetic correlation functions in the solar wind. Data sets from these missions can, in principle, also be used to compute so-called Eulerian correlation functions. These temporal correlations are essential for understanding the dynamics of solar wind turbulence. In the current article

Jeffrey Giansiracusa

We consider mapping class groups \Gamma(M) = pi_0 Diff(M fix \partial M) of smooth compact simply connected oriented 4-manifolds M bounded by a collection of 3-spheres. We show that if M contains CP^2 (with either orientation) as a connected summand then \Gamma(M) is independent of the number of boundary components. By repackaging classical results of Wall,

Daniel Greenberger, Michael Horne, Anton Zeilinger, Marek Zukowski

We again consider (as in a companion paper) an entangled two-particle state that is produced from two independent down-conversion sources by the process of &#34;entanglement-swapping&#34;, so that the particles have never met. We show that there is a natural extension of the Einstein-Pololsky-Rosen discussion of &#34;elements of reality&#34; to include ineff

Girish S. Setlur

It is shown that it is possible to bosonize fermions in any number of dimensions using the hydrodynamic variables, namely the velocity potential and density. The slow part of the Fermi field is defined irrespective of dimensionality and the commutators of this field with currents and densities are exponentiated using the velocity potential as conjugate to th

I. V. Bobkova

The behavior of dc subgap current in magnetic quantum point contact is discussed for the case of low-transparency junction with different tunnel probabilities for spin-up ($D_\uparrow$) and spin-down ($D_\downarrow$) electrons. Due to the presence of Andreev bound states $\pm ε_0$ in the system the positions of subgap electric current steps $eV_n = (Δ\pm ε_0

Ezio Vasselli

We introduce the notions of multiplier C*-category and continuous bundle of C*-categories, as the categorical analogues of the corresponding C*-algebraic notions. Every symmetric tensor C*-category with conjugates is a continuous bundle of C*-categories, with base space the spectrum of the C*-algebra associated with the identity object. We classify tensor C*

H. B. Heersche, Z. de Groot, J. A. Folk, H. S. J. van der Zant

We report transport measurements through a single-molecule magnet, the Mn12 derivative [Mn12O12(O2C-C6H4-SAc)16(H2O)4], in a single-molecule transistor geometry. Thiol groups connect the molecule to gold electrodes that are fabricated by electromigration. Striking observations are regions of complete current suppression and excitations of negative differenti

Marco Debernardi, Roberto Paoletti

Suppose given a complex projective manifold $M$ with a fixed Hodge form $Ω$. The Bohr-Sommerfeld Lagrangian submanifolds of $(M,Ω)$ are the geometric counterpart to semi-classical physical states, and their geometric quantization has been extensively studied. Here we revisit this theory in the equivariant context, in the presence of a compatible (Hamiltonian

A. V. Gulov, V. V. Skalozub

The LEP2 data set on the Bhabha process is analyzed with the aim to detect the signals of the heavy virtual Z&#39; gauge bosons. The state interacting with the left-handed standard-model doublets and called the Chiral Z&#39; is investigated. This particle was introduced already as the low-energy state allowed by the renormalizability of the model. The contri

Yuko Hori, Ashok Prasad, Jane&#39; Kondev

We study the mechanical properties of semiflexible polymers when the contour length of the polymer is comparable to its persistence length. We compute the exact average end-to-end distance and shape of the polymer for different boundary conditions, and show that boundary effects can lead to significant deviations from the well-known long-polymer results. We

Juyong Park

Ranking a set of objects from the most dominant one to the least, based on the results of paired comparisons, proves to be useful in many contexts. Using the rankings of teams or individuals players in sports to seed tournaments is an example. The quality of a ranking is often evaluated by the number of violations, cases in which an object is ranked lower th

N. Kanekar, C. L. Carilli, G. I. Langston, G. Rocha

We have detected the four 18cm OH lines from the $z \sim 0.765$ gravitational lens toward PMN J0134-0931. The 1612 and 1720 MHz lines are in conjugate absorption and emission, providing a laboratory to test the evolution of fundamental constants over a large lookback time. We compare the HI and OH main line absorption redshifts of the different components in

D. S. Durfee, Y. K. Shaham, M. A. Kasevich

We report on a study of the long-term stability and absolute accuracy of an atom interferometer gyroscope. This study included the implementation of an electro-optical technique to reverse the vector area of the interferometer for reduced systematics and a careful study of systematic phase shifts. Our data strongly suggests that drifts less than 96 $μ$deg/hr

O. Sapin, H. R. Jauslin, S. Weigert

We generalize the definition of quantum Anosov properties and the related Lyapunov exponents to the case of quantum systems driven by a classical flow, i.e. skew-product systems. We show that the skew Anosov properties can be interpreted as regular Anosov properties in an enlarged Hilbert space, in the framework of a generalized Floquet theory. This extensio

Miroslav Pardy

The hydrodynamical model of quantum mechanics based on the Schroedinger equation is combined with the magnetohydrodynamical term to form so called quantum magnetohydrodynamic equation. It is shown that the quantum correction to the Alfven waves follows from this new equation. The possible generalization is considered for the so called nonlinear Schroedinger