February 2005 arXiv papers — page 7

Shihoko Ishii

This paper gives a map from the set of families of arcs on a variety to the set of valuations on the rational function field of the variety We characterize a family of arcs which corresponds to a divisorial valuation by this map. We can see that both the Nash map and a certain McKay correspondence are the restrictions of this map. This paper also gives the a

Dietrich Burde

We study the matrix equation $XA-AX=X^p$ in $M_n(K)$ for $1< p <n$. It is shown that every matrix solution $X$ is nilpotent and that the generalized eigenspaces of $A$ are $X$-invariant. For $A$ being a full Jordan block we describe how to compute all matrix solutions. Combinatorial formulas for $A^mX^{\ell},X^{\ell}A^m$ and $(AX)^{\ell}$ are given. The case

Franc Forstneric

We construct a real analytic Levi-flat hypersurface M in a neighborhood of an ellipsoid B in C^2 such that the each leaf of the Levi foliation of M is a complex disc, M intersects the boundary of B transversely, and the intersection A of M with B has the following properties: (i) the closure of A is diffeomorphic to the ball in R^3 and has a basis of Stein n

Elise Janvresse, Thierry de la Rue, Yvan Velenik

Let T be the Pascal-adic transformation. For any measurable function g, we consider the corrections to the ergodic theorem sum_{k=0}^{j-1} g(T^k x) - j/l sum_{k=0}^{l-1} g(T^k x). When seen as graphs of functions defined on {0,...,l-1}, we show for a suitable class of functions g that these quantities, once properly renormalized, converge to (part of) the gr

R. Jackiw, Carlos Nunez, S. -Y. Pi

We describe a mechanism that drives the Cosmological Constant to zero value. This mechanism is based on the quantum triviality of $λϕ^4$ field theory and works in $AdS$ space. Some subtleties of the model are discussed.

James Babington, Johanna Erdmenger

We consider N=1 supersymmetric gauge theories in which the couplings are allowed to be space-time dependent functions. Both the gauge and the superpotential couplings become chiral superfields. As has recently been shown, a new topological anomaly appears in models with space-time dependent gauge coupling. Here we show how this anomaly may be used to derive

Domenico Orlando

An exact heterotic string theory on an AdS2xS2 background supported by an electromagnetic flux is found as a marginal deformation of an SL(2,R)xSU(2) WZW model. Based on a talk given at NATO Advanced Study Institute and EC Summer School on String Theory: from Gauge Interactions to Cosmology, Cargese, Corsica, France, 7 Jun - 19 Jun 2004.

Anton Kapustin

We argue that for a certain class of symplectic manifolds the category of A-branes (which includes the Fukaya category as a full subcategory) is equivalent to a noncommutative deformation of the category of B-branes (which is equivalent to the derived category of coherent sheaves) on the same manifold. This equivalence is different from Mirror Symmetry and a

Ion I. Cotăescu

The Gross-Perry-Sorkin spacetime, formed by the Euclidean Taub-NUT space with the time trivially added, is the appropriate background of the Dirac magnetic monopole without an explicit mass term. One remarks that there exists a very simple five-dimensional metric of spacetimes carrying massive magnetic monopoles that is an exact solution of the vacuum Einste

M. J. Duff

Branes now occupy center stage in theoretical physics as microscopic components of M-theory, as the higher-dimensional progenitors of black holes and as entire universes in their own right. Their history has been a checkered one, however. Here we list some of the milestones, starting with Dirac&#39;s 1962 paper. Asim Barut was an early pioneer.

Yao-Zhong Zhang

Super coherent states are useful in the explicit construction of representations of superalgebras and quantum superalgebras. In this contribution, we describe how they are used to construct (quantum) boson-fermion realizations and representations of (quantum) superalgebras. We work through a few examples: $osp(1|2)$ and its quantum version $U_t[osp(1|2)]$, $

M. C. Gonzalez-Garcia, F. Halzen, M. Maltoni

This paper investigates the physics reach of the IceCube neutrino detector when it will have collected a data set of order one million atmospheric neutrinos with energies in the 0.1 \sim 10^4 TeV range. The paper consists of three parts. We first demonstrate how to simulate the detector performance using relatively simple analytic methods. Because of the hig

J. -P. Blaizot, E. Iancu, K. Itakura, D. N. Triantafyllopoulos

We propose an effective theory which governs Pomeron dynamics in QCD at high energy, in the leading logarithmic approximation, and in the limit where N_c, the number of colors, is large. In spite of its remarkably simple structure, this effective theory generates precisely the evolution equations for scattering amplitudes that have been recently deduced from

Carlo Michel Carloni Calame, Guido Montagna, Oreste Nicrosini, Michele Treccani

Precision studies of single W and Z production processes at hadron colliders require progress in the calculation of electroweak radiative corrections. To this end, higher-order QED corrections to the neutral-current Drell-Yan process, due to multiple photon radiation in Z leptonic decays, are calculated. Particular attention is paid to the effects induced by

Pedro Costa, M. C. Ruivo, C. A. de Sousa, Yu. L. Kalinovsky

We explore the effects of breaking and restoration of chiral and axial symmetries using an extended three-flavor Nambu-Jona-Lasinio model that incorporates explicitly the axial anomaly through the &#39;t Hooft interaction. We implement a temperature (density) dependence of the anomaly coefficient motivated by lattice results for the topological susceptibilit

K. Kovarik

We present the complete one-loop corrections to the sfermion pair production process e+e- -> sf_i sf_j (f = t, b, tau, nu_tau, u, d, s, c) in the Minimal Supersymmetric Standard Model. Our results also include the previously calculated SUSY-QCD corrections. We present some details of the renormalization scheme used. It is found that the weak corrections are

Brandon Carter

Composite rigging systems, involving membranes that meet on strings that meet on monopoles, arise naturally by the Kibble mechanism as topological defects in field theories involving spontaneous symmetry breaking. Such systems will tend to freeze out into static lattice type configurations with energy contribution ultimately be provided by the membranes. It

L. C. Bland, F. Bieser, R. L. Brown, H. J. Crawford

The rapidity dependence of inclusive and coincident particle production in d(p)+Au collisions at RHIC can be used to probe nuclear parton distribution functions down to small momentum fractions where theory anticipates that parton saturation could be present. This paper describes how such experiments could be completed.

K. Zuber

The current experimental status of neutrino physics is reviewed. It contains the evidences for a non-vanishing neutrino rest mass from neutrino oscillation searches. In addition an outlook is given on determining the various mixing matrix elements and mass differences more precisely with new experiments. Of special interest is the value of the mixing angle θ

Paola Zizzi

We assume that space-time at the Planck scale is discrete, quantised in Planck units and &#34;qubitsed&#34; (each pixel of Planck area encodes one qubit), that is, quantum space-time can be viewed as a quantum computer. Within this model, one finds that quantum space-time itself is entangled, and can quantum-evaluate Boolean functions which are the laws of P

Radhakrishnan Srinivasan, H. P. Raghunandan

A theoretical model of truly autonomic computing systems (ACS), with infinitely many constraints, is proposed. An argument similar to Turing&#39;s for the unsolvability of the halting problem, which is permitted in classical logic, shows that such systems cannot exist. Turing&#39;s argument fails in the recently proposed non-Aristotelian finitary logic (NAFL

En-Che Yang, Cem Kirman, Jon Lawrence, Lev N. Zakharov

High-field electron paramagnetic resonance (HFEPR) spectra were collected at several frequencies for single crystal [Zn3.91Ni0.09(hmp)4(dmb)4Cl4] (1), where dmb is 3,3-dimethyl-1-butanol and hmp is the monoanion of 2-hydroxymethylpyridine. This crystal is isostructural to [Ni4(hmp)4(dmb)4Cl4] (2), which has been characterized to be a single-molecule magnet (

L. de&#39; Medici, A. Georges, G. Kotliar, S. Biermann

We study how a finite hybridization between a narrow correlated band and a wide conduction band affects the Mott transition. At zero temperature, the hybridization is found to be a relevant perturbation, so that the Mott transition is suppressed by Kondo screening. In contrast, a first-order transition remains at finite temperature, separating a local moment

N. O. Moreno, A. Lobos, A. A. Aligia, E. D. Bauer

Magnetic susceptibility, heat capacity, and electrical resistivity measurements have been carried out on single crystals of the intermediate valence compounds Yb2Rh3Ga9 and Yb2Ir3Ga9. These measurements reveal a large anisotropy due apparently to an interplay between crystalline electric field (CEF) and Kondo effects. The temperature dependence of magnetic s

Florian Marquardt, J. G. E. Harris, S. M. Girvin

We analyze the nonlinear dynamics of a high-finesse optical cavity in which one mirror is mounted on a flexible mechanical element. We find that this system is governed by an array of dynamical attractors, which arise from phase-locking between the mechanical oscillations of the mirror and the ringing of the light intensity in the cavity. We describe an anal

Ulrike Lueders, Manuel Bibes, Jean-Francois Bobo, Matteo Cantoni

Bulk NiFe2O4 is an insulating ferrimagnet. Here, we report on the epitaxial growth of spinel NiFe2O4 ultrathin films onto SrTiO3 single-crystals. We will show that - under appropriate growth conditions - epitaxial stabilization leads to the formation of a spinel phase with magnetic and electrical properties that radically differ from those of the bulk materi

Huynh Thanh Duc, T. Meier, S. W. Koch

The coherent optical injection and temporal decay of spin and charge currents in semiconductor heterostructures is described microscopically, including excitonic effects, carrier LO-phonon and carrier-carrier scattering, as well as nonperturbative light-field-induced intraband and interband excitations. A nonmonotonous dependence of the currents on the inten

I. Leonov, A. N. Yaresko, V. N. Antonov, J. P. Attfield

Charge ordering in the low-temperature monoclinic structure of iron oxoborate (Fe2OBO3) is investigated using the local spin density approximation (LSDA)+U method. While the difference between t_{2g} minority occupancies of Fe^{2+} and Fe^{3+} cations is large and gives direct evidence for charge ordering, the static &#34;screening&#34; is so effective that

L. L. A. Adams, B. W. Lang, A. M. Goldman

Low temperature scanning tunneling microscope images and spectroscopic data have been obtained on subnanometer size Pb clusters fabricated using the technique of buffer layer assisted growth. Discrete energy levels were resolved in current-voltage characteristics as current peaks rather than current steps. Distributions of peak voltage spacings and peak curr

D. Temkin

We demonstrate that for a migration of a liquid layer between the melting and the solidification front an exact steady-state solution with two parabolic fronts can be found. A necessary condition hereby is that the temperature of the solidification front exceeds the temperature of the melting front (both temperatures are supposed to be constant). It is shown

V. P. Mineev, M. E. Zhitomirsky

We argue that the inhomogeneous A-phase in aerogel is energetically more preferable than the &#34;robust&#34; phase suggested by I. A. Fomin, JETP Lett. 77, 240 (2003); cond-mat/0302117 and cond-mat/0401639.

Ralph Schenker, Michael N. Leuenberger, Gregory Chaboussant, Daniel Loss

A detailed investigation of the unusual dynamics of the magnetization of (Et4N)3Fe2F9 (Fe2), containing isolated [Fe2F9]3- dimers, is presented and discussed. Fe2 possesses an S=5 ground state with an energy barrier of 2.40 K due to an axial anisotropy. Poor thermal contact between sample and bath leads to a phonon bottleneck situation, giving rise to butter

Giulio Casati, Baowen LI

In this paper we give a brief review of the relation between microscopic dynamical properties and the Fourier law of heat conduction as well as the connection between anomalous conduction and anomalous diffusion. We then discuss the possibility to control the heat flow.

James L. Harden, Fred C. MacKintosh, Peter D. Olmsted

We study the stability and shapes of domains with spontaneous curvature in fluid films and membranes, embedded in a surrounding membrane with zero spontaneous curvature. These domains can result from the inclusion of an impurity in a fluid membrane, or from phase separation within the membrane. We show that for small but finite line and surface tensions and

B. J. LeRoy, A. C. Bleszynski, K. E. Aidala, R. M. Westervelt

An imaging interferometer was created in a two-dimensional electron gas by reflecting electron waves emitted from a quantum point contact (QPC) with a circular mirror. Images of electron flow obtained with a scanning probe microscope at liquid He temperatures show interference fringes when the mirror is energized. A quantum phase shifter was created by movin

Peng Zhang, Zhaoxin Xu, Heping Ying, Jianhui Dai

The S=1/2 Heisenberg chain with bond alternation and randomness of antiferromagnetic (AFM) and ferromagnetic (FM) interactions is investigated by quantum Monte Carlo simulations of loop/cluster algorithm. Our results have shown interesting finite temperature magnetic properties of this model. The relevance of our study to the observed results of the material

Andrey V. Chubukov, Dmitrii L. Maslov, Suhas Gangadharaiah, Leonid I. Glazman

We consider the non-analytic temperature dependences of the specific heat coefficient, C(T)/T, and spin susceptibility, χ_{s} (T), of 2D interacting fermions beyond the weak-coupling limit. We demonstrate within the Luttinger-Ward formalism that the leading temperature dependences of C(T)/T and χ_s (T) are linear in T, and are described by the Fermi liquid t

Raja Paul, Sanjay Puri, Heiko Rieger

We present results from extensive Monte Carlo (MC) simulations of domain growth in ferromagnets and binary mixtures with quenched disorder. These are modeled by the &#34;random-bond Ising model&#34; and the &#34;dilute Ising model&#34; with either nonconserved (Glauber) spin-flip kinetics or conserved (Kawasaki) spin-exchange kinetics. In all cases, our MC r

M. de Llano, F. J. Sevilla, M. A. Solis, J. J. Valencia

For the Cooper/BCS model interaction in superconductors (SCs) it is shown: a) how BCS-Bose crossover picture transition temperatures Tc, defined self-consistently by both the gap and fermion-number equations, require unphysically large couplings to differ significantly from the Tc of ordinary BCS theory defined without the number equation since here the chem

R. G. Pereira, E. Miranda

We investigate the effect of strong spin-orbit interaction on the electronic transport through non-magnetic impurities in one-dimensional systems. When a perpendicular magnetic field is applied, the electron spin polarization becomes momentum-dependent and spin-flip scattering appears, to first order in the applied field, in addition to the usual potential s

D. Kechrakos, N. Papanikolaou, K. N. Trohidou, T. Dietl

Monte Carlo simulations, in which the Schrodinger equation is solved at each Monte Carlo sweep, are employed to assess the influence of magnetization fluctuations,short-range antiferromagnetic interactions, disorder, magnetic polaron formation, and spin-Peierls instability on the carrier-mediated Ising ferromagnetism in two-dimensional electronic systems. Th

Asantha Cooray, Naoki Seto

The Laser Interferometer Space Antenna (LISA) is expected to detect N ~ 22 [x10^(+/- 1)] close white dwarf binaries in the Large Magellanic Cloud (LMC) through their gravitational radiation with signal-to-noise ratios greater than 10 in observational durations of 3 years or more. In addition to chirp mass, location on the sky, and other binary parameters, th

S. J. Sturner, C. R. Shrader

The well known black-hole X-ray binary transient XTE J1550-564 underwent an outburst during the spring of 2003 which was substantially underluminous in comparison to previous periods of peak activity in that source. In addition, our analysis shows that it apparently remained in the hard spectral state over the duration of that outburst. This is again in shar

Kevin R. Covey, Thomas P. Greene, Greg W. Doppmann, Charles J. Lada

We report on the angular momentum content of heavily embedded protostars based on our analysis of the projected rotation velocities (v sin i s) of 38 Class I/flat spectrum young stellar objects presented by Doppmann et al (2005). After correcting for projection effects, we find that infrared-selected Class I/flat spectrum objects rotate significantly more qu

J. -L. Atteia, N. Kawai, R. Vanderspek, G. Pizzichini

GRB 020124 and GRB 030323 constitute half the sample of gamma-ray bursts with a measured redshift greater than 3. This paper presents the temporal and spectral properties of these two gamma-ray bursts detected and localized with HETE-2. While they have nearly identical redshifts (z=3.20 for GRB 020124, and z=3.37 for GRB 030323), these two GRBs span about an

Jeffrey D. Crane, Steven R. Majewski, Richard J. Patterson, Michael F. Skrutskie

The Fan Observatory Bench Optical Spectrograph (FOBOS) is intended for single-object optical spectroscopy at moderate resolution (R~1500-3000) using a fiber-fed, bench-mounted design to maintain stability. Whenever possible, the instrument uses off-the-shelf components to maintain a modest cost. FOBOS supports Galactic astronomy projects that require consist

A. Bongiovanni, G. Bruzual, G. Magris, J. Gallego

We present the CIDA-UCM-Yale (Centro de Investigaciones de Astronomia, Universidad Complutense de Madrid and Yale University) survey for Halpha+[NII]6549,6584 emission-line galaxies using objective-prism spectra. The most important properties of a catalogue with 427 entries and significant subsets are analysed. The complete sample contains 183 statistically

B. Lanzoni, B. Guiderdoni, G. A. Mamon, J. Devriendt

High-resolution N-body re-simulations of 15 massive (10^{14}-10^{15} Msun) dark matter haloes have been combined with the hybrid galaxy formation model GalICS (Hatton et al. 2003), to study the formation and evolution of galaxies in clusters, within the framework of the hierarchical merging scenario. New features in GalICS include a better description of gal

Eric E. Mamajek

The recent availability of accurate proper motion catalogs for millions of stars on the sky (e.g. Tycho-2, UCAC) can benefit projects for which age estimates are needed for stars that are plausibly young (<100 Myr-old) and within a few hundred pc of the Sun. Here I summarize how accurate proper motions have been useful in (1) identifying new, nearby, post-T

G. Ghirlanda, G. Ghisellini, C. Firmani, A. Celotti

We derive the peak luminosity - peak energy (L_iso - E_peak) correlation using 22 long Gamma-Ray Bursts (GRBs) with firm redshift measurements. We find that its slope is similar to the correlation between the time integrated isotropic emitted energy E_iso and E_peak (Amati et al. 2002). For the 15 GRBs in our sample with estimated jet opening angle we comput

John Bally, Hans Zinnecker

The observational consequences of the merger scenario for massive star formation are explored and contrasted with the gradual accumulation of mass by accretion. Protostellar mergers may produce high luminosity infrared flares lasting years to centuries followed by a luminosity decline on the Kelvin-Helmholtz time-scale of the merger product. Mergers may be s

D. Apai, L. V. Toth, Th. Henning, R. Vavrek

We present deep HST/NICMOS observations peering through the outflow cavity of the protostellar candidate IRAS 04381+2540 in the Taurus Molecular Cloud-1. A young stellar object as central source, a jet and a very faint and close (0.6&#34;) companion are identified. The primary and the companion have similar colours, consistent with strong reddening. We argue

Yasuhiro Hashimoto, J. Patrick Henry, Guenther Hasinger, G. Szokoly

We present a study of the galaxy population in the cluster RX J1053.7+5735, one of the most distant X-ray selected clusters of galaxies, which also shows an unusual double-lobed X-ray morphology, indicative of a possible equal-mass cluster merger. Using Keck-DEIMOS spectroscopic observations of galaxies in the 2x1.5 arcmin region surrounding RX J1053.7+5735,

A. D. Myers, P. J. Outram, T. Shanks, B. J. Boyle

We cross-correlate APM and SDSS galaxies with background QSOs from the 2dF QSO Redshift Survey, and detect a significant (2.8sigma) anti-correlation. The lack of a signal between 2dF stars and our galaxy samples suggests the anti-correlation is not due to a systematic error. The possibility that dust in the foreground galaxies could produce the anti-correlat

Anna Geminale, Piotr Popowski

We present the analysis of a large sample of lines of sight with extinction curves covering wavelength range from near-infrared (NIR) to ultraviolet (UV). We derive total to selective extinction ratios based on the Cardelli, Clayton and Mathis (1989, CCM) law, which is typically used to fit the extinction data both for diffuse and dense interstellar medium.

Clare L. Dobbs, Ian A. Bonnell, Paul C. Clark

We present numerical investigations into the formation of massive stars from centrally condensed turbulent cores. The results of five hydrodynamical simulations are described, following the collapse of the core, fragmentation and the formation of small clusters of protostars. We generate two different initial turbulent velocity fields corresponding to power-

A. Garcia-Rissmann, L. R. Vega, N. V. Asari, R. Cid Fernandes

We present a spectroscopic atlas of active galactic nuclei covering the region around the 8498, 8542, 8662 Calcium triplet (CaT) lines. The sample comprises 78 objects, divided into 43 Seyfert 2s, 26 Seyfert 1s, 3 Starburst and 6 normal galaxies. The spectra pertain to the inner ~300 pc in radius, and thus sample the central kinematics and stellar population

O. Stawicki

A nonlinear description for perpendicular particle diffusion in strong electromagnetic fluctuations is developed by using the fundamental Newton-Lorentz equation. Although not based on the same approach, the recently presented nonlinear guiding center (NLGC) theory is recovered as a special case. The approach used here is rather based on the argument that a

Ehud Nakar, Tsvi Piran

We discuss the optical and radio early afterglow emission of the reverse shock that crosses a baryonic ejecta as it interacts with the external interstellar medium (ISM). We show that the peak of the optical flash divides the light curve of the reverse shock into two distinctive phases. The emission after the peak depends weakly on the initial conditions of

Ryo Yamazaki, Kunihito Ioka, Takashi Nakamura, Kenji Toma

A possible unified model of short and long gamma-ray bursts (GRBs), X-ray rich GRBs, and X-ray flashes is proposed. It is assumed that the jet of a GRB consists of many emitting sub-shells (i.e., an inhomogeneous jet model). The multiplicity of the sub-shells along a line of sight n_s is an important parameter. If n_s is large (>>1) the event looks like a lo

Amr El-Zant

Simple simulations suggest that the phase space structure of haloes identified in cosmological calculations is invariant under the dynamics induced by sinking substructure satellites -- the background expands so as to leave the total distribution unchanged. We use a Fokker-Planck formulation to show that this is the case. The solutions obtained are valid for

E. Berger, D. B. Fox, S. R. Kulkarni, W. Krzeminski

We present optical and near-infrared searches for afterglow emission from the first four Swift bursts with accurate positions from the X-ray Telescope (XRT). Using telescopes at Las Campanas, Keck, and Palomar observatories we rapidly identified and followed up afterglows for three of the four bursts. The burst positions were also observed with the Very Larg

C. Marois, B. Macintosh, I. Song, T. Barman

AB Dor C, a low-mass companion to the young star AB Dor A has recently been imaged. Direct detection and astrometric observations have been used to solve the AB Dor C orbit and obtain a dynamical mass estimate. Near-infrared magnitudes and effective temperatures from models have then been compared with observed values. Models and observations disagree at mor

R. Quast, D. Reimers, A. Smette, O. Garcet

Spectroscopy of QSO absorption lines provides essential observational input for the study of nucleosynthesis and chemical evolution of galaxies at high redshift. But new observations may indicate that present chemical abundance data are biased due to deficient spectral resolution and unknown selection effects: Recent high-resolution spectra reveal the hither

Naoyuki Haba, Nobuchika Okada

We derive in detail a condition on the Higgs mass parameters that is necessary for the recently proposed ``split supersymmetry&#39;&#39; (split SUSY) scenario to provide a realistic magnitude of $\tan β$. The nature of this condition can be understood by showing how the Higgs sector of the minimal supersymmetric Standard Model reduces to that of the Standard

Kazunori Kohri, Ramesh Narayan, Tsvi Piran

We suggest that part of the infalling material during the core-collapse of a massive star goes into orbit around the compact core to form a hot, dense, centrifugally-supported accretion disk whose evolution is strongly influenced by neutrino interactions. Under a wide range of conditions, this neutrino-dominated accretion flow will be advection-dominated and

Ngoc-Khanh Tran

We study the gauge symmetry factorizability by boundary conditions on intervals of any dimensions. With Dirichlet-Neumann BCs, the Kaluza-Klein decomposition in five-dimension for arbitrary gauge group can always be factorized into that for separate subsets of at most two gauge symmetries, and so is completely solvable. Accordingly, we formulate a limit theo

F. Javier Gallego, Miguel González, Bangere P. Purnaprajna

In this article we present a unified way to smooth certain multiple structures called ropes on smooth varieties. We prove that most ropes of arbitrary multiplicity, supported on smooth curves can be smoothed. By a rope being smoothable we mean that the rope is the flat limit of a family of smooth, irreducible curves. To construct a smoothing, we connect, on

Vitor Cardoso, Shijun Yoshida

Black branes and strings are generally unstable against a certain sector of gravitational perturbations. This is known as the Gregory-Laflamme instability. It has been recently argued that there exists another general instability affecting many rotating extended black objects. This instability is in a sense universal, in that it is triggered by any massless

Antony Lewis

Modelling of the weak lensing of the CMB will be crucial to obtain correct cosmological parameter constraints from forthcoming precision CMB anisotropy observations. The lensing affects the power spectrum as well as inducing non-Gaussianities. We discuss the simulation of full sky CMB maps in the weak lensing approximation and describe a fast numerical code.

Roman V. Buniy, Stephen D. H. Hsu

We show that violation of the null energy condition implies instability in a broad class of models, including classical gauge theories with scalar and fermionic matter as well as any perfect fluid. When applied to the dark energy, our results imply that $w = p / ρ$ is unlikely to be less than -1.

Fabrizio Zanello

Given a vector space $V$ of homogeneous polynomials of the same degree over an infinite field, consider a generic subspace $W$ of $V$. The main result of this paper is a lower-bound (in general sharp) for the dimensions of the spaces spanned in each degree by the partial derivatives of the forms generating $W$, in terms of the dimensions of the spaces spanne

Bert Cosemans, Geert Smet

We find 5D gauged supergravity theories exhibiting stable de Sitter vacua. These are the first examples of stable de Sitter vacua in higher-dimensional (D>4) supergravity. Non-compact gaugings with tensor multiplets and R-symmetry gauging seem to be the essential ingredients in these models. They are however not sufficient to guarantee stable de Sitter vacua

A. Cuoco, J. Lesgourgues, G. Mangano, S. Pastor

It is usually assumed that relic neutrinos possess a Fermi-Dirac distribution, acquired during thermal equilibrium in the Early Universe. However, various mechanisms could introduce strong distortions in this distribution. We perform a Bayesian likelihood analysis including the first moments of the three active neutrino distributions as free parameters, and

R. P. Panguluri, K. C. Ku, T. Wojtowicz, X. Liu

We investigate the applicability of spin polarization measurements using Andreev reflection in a point contact geometry in heavily doped dilute magnetic semiconductors, such as (Ga,Mn)As. While we observe conventional Andreev reflection in non-magnetic (Ga,Be)As epilayers, our measurements indicate that in ferromagnetic (Ga,Mn)As epilayers with comparable ho

Neil Lambert

We discuss the effective action for weak G_2 compactifications of M-theory. The presence of fluxes acts as a source for the the axions and drives the Freund-Rubin parameter to zero. The result is a stable non-supersymmetric vacuum with a negative cosmological constant. We also give the superpotential which generates the effective potential and discuss a simp

Antonio S. de Castro

The problem of a spinless particle subject to a general mixing of vector and scalar inversely linear potentials in a two-dimensional world is analyzed. Exact bounded solutions are found in closed form by imposing boundary conditions on the eigenfunctions which ensure that the effective Hamiltonian is Hermitian for all the points of the space. The nonrelativi

David Mattingly

Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violatin

Piet W. Brouwer, Austen Lamacraft, Karsten Flensberg

We develop a non-equilibrium theory to describe weak Coulomb blockade effects in open quantum dots. Working within the bosonized description of electrons in the point contacts, we expose deficiencies in earlier applications of this method, and address them using a 1/N expansion in the inverse number of channels. At leading order this yields the self-consiste

Eddy Yusuf, Kun Yang

We study the low-energy collective excitations and dynamical response functions of weakly coupled random antiferromagnetic spin-1/2 chains. The interchain coupling leads to Neel order at low temperatures. We use the real-space renormalization group technique to tackle the intrachain couplings and treat the interchain couplings within the Random Phase Approxi

E. Caurier, F. Nowacki, A. Poves

Large scale shell model calculations in two major oscillator shells (sd and pf) describe simultaneously the super-deformed excited band of 36Ar and its low-lying states of dominant sd character. In addition, several two particle two hole states and a side band of negative parity are also well reproduced. We explain the appearance of the super-deformed band a

Kazunori Kohri, Masahiro Yamaguchi, Jun&#39;ichi Yokoyama

We propose a new scenario of non-thermal production of neutralino cold dark matter, in which the overproduction problem of lightest supersymmetric particles (LSPs) in the standard thermal history is naturally solved. The mechanism requires a heavy modulus field which decays mainly to ordinary particles releasing large entropy to dilute gravitinos produced ju

Laurent Sanchez-Palencia, Luis Santos

We analyze the physics of Bose-Einstein condensates confined in 2D quasi-periodic optical lattices, which offer an intermediate situation between ordered and disordered systems. First, we analyze the time-of-flight interference pattern that reveals quasi-periodic long-range order. Second, we demonstrate localization effects associated with quasi-disorder as

Shinji Hirano

We argue that the closed string energy in the bulk bouncing tachyon background is to be quantised in a simple manner as if strings were trapped in a finite time interval. We discuss it from three different viewpoints; (1) the timelike continuation of the sinh-Gordon model, (2) the dual matrix model description of the (1+1)-dimensional string theory with the

S. Diehl, C. Wetterich

We describe the gas of ultracold fermionic atoms by a functional integral for atom and molecule fields. The crossover from Bose-Einstein condensation (BEC) to BCS-type superfluidity shows universal features in terms of a concentration parameter for the ratio between scattering length and average interatomic distance. We discuss the relevance of the Yukawa co

Ralf Rapp

The potential of heavy quarks as probes of the environment produced in hadronic and heavy-ion reactions is discussed. A key role is played by coalescence processes and/or resonance formation which are promising candidates to provide a comprehensive understanding of phenomena associated with reinteractions of both open and hidden heavy-quark states.

Alexander Dolgov, Diego N. Pelliccia

Starting from the equation of motion of the quantum operator of a real scalar field phi in de Sitter space-time, a simple differential equation is derived which describes the evolution of quantum fluctuations <phi^2> of this field. Full de Sitter invariance is assumed and no ad hoc infrared cutoff is introduced. This equation is solved explicitly and in mass

Takashi Kimura, Xiaobo Liu

In this paper, we give a new genus-3 topological recursion relation for Gromov-Witten invariants of compact symplectic manifolds. This formula also applies to intersection numbers on moduli spaces of spin curves. A by-product of the proof of this formula is a new relation in the tautological ring of the moduli space of 1-pointed genus-3 stable curves.

R. Blomme, S. Van Loo, M. De Becker, G. Rauw

We present a radio lightcurve of the O5.5 III(f+) star HD 168112, based on archive data from the Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA). The fluxes show considerable variability and a negative spectral index, thereby confirming that HD 168112 is a non-thermal radio emitter. The non-thermal radio emission is believed to be due

T. Opatrny, J. Fiurasek

Present schemes involving the quantum non-demolition interaction between atomic samples and off-resonant light pulses allow us to store quantum information corresponding to a single harmonic oscillator (mode) in one multiatomic system. We discuss the possibility to involve several coherences of each atom so that the atomic sample can store information contai

Gábor Simonyi, Gábor Tardos, Siniša T. Vrećica

The local chromatic number of a graph G is the number of colors appearing in the most colorful closed neighborhood of a vertex minimized over all proper colorings of G. We show that two specific topological obstructions that have the same implications for the chromatic number have different implications for the local chromatic number. These two obstructions

A. Toschi, M. Capone, M. Ortolani, P. Calvani

We compare calculations based on the Dynamical Mean-Field Theory of the Hubbard model with the infrared spectral weight $W(Ω,T)$ of La$_{2-x}$Sr$_x$CuO$_4$ and other cuprates. Without using fitting parameters we show that most of the anomalies found in $W(Ω,T)$ with respect to normal metals, including the existence of two different energy scales for the dopi

Mariusz Bialecki

First, we recall the algebro-geometric method of construction of finite field valued solutions of the discrete KP equation and next we perform a reduction of the dKP equation to the discrete 1D Toda equation. This gives a method of construction of solutions of the discrete 1D Toda equation taking values in a finite field.

J. P. Pridham

The aim of this paper is to study the pro-algebraic fundamental group of a compact Kaehler manifold. Following work by Simpson, the structure of this group&#39;s pro-reductive quotient is already well understood. We show that Hodge-theoretic methods can also be used to establish that the pro-unipotent radical is quadratically presented. This generalises both

Fardin Kheirandish, Majid Amooshahi

Quantum field theory of a damped vibrating string as the simplest dissipative scalar field investigated by its coupling with an infinit number of Klein-Gordon fields as the environment by introducing a minimal coupling method. Heisenberg equation containing a dissipative term proportional to velocity obtained for a special choice of coupling function and qua

Francis Halzen, Dan Hooper

The AMANDA neutrino telescope has recently reported the detection of high-energy neutrinos spatially and temporally coincident with the flaring of the TeV blazar 1ES 1959+650. At present, the statistical significance of this observation cannot be reliably assessed, however. In this letter, we investigate whether circumstances exist where the source can produ

Heping Zeng, Jian Wu, Kun Wu, Han Xu

This paper has been withdrawn by the authors

Tadayuki Kodama, the PISCES team

We have started PISCES project; a panoramic imaging and spectroscopic survey of distant clusters on Subaru. It exploits the unique wide-field imaging capability of Suprime-Cam, which provides a 34&#39;x27&#39; field of view corresponding to a physical area of 16x13Mpc^2 at z~1. We plan to target 15 clusters in total at 0.4<z<1.3. In this paper, we report on

Valery P. Dmitriyev

The special theory of relativity is constructed demanding the retention of the rectilinear form of a trajectory and invariance of the wave equation under linear transformations of space and time coordinates. The usual approach to relativity based on manipulations with the impulse of light is shown to be owing to that the symmetry of the particular solution o

Da Qing Liu, Ji Ming Wu

In this note we show an empirical formula of quark masses, which is found by implementing a least squares fit. In this formula the measured QCD coupling is almost a &#34;best fitting coupling&#34;.