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Sep 23, 2013
09/13

by
Guo-Li Liu

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Topcolor-assisted technicolor (TC2) model predicts the existence of the top-pions and the CP-even top-Higgs with large flavor-changing couplings to the top quark, which at tree-level can mediate the top quark three-body decay t -> cb\bar{b}. In this work we study this decay, showing the dependence of the decay rate on the relevant TC2 parameters and comparing the results with the predictions in the minimal supersymmetric model. We find that the decay rate in the TC2 model is much larger than...

Source: http://arxiv.org/abs/0903.2619v1

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Sep 23, 2013
09/13

by
Cosmo Lupo; Vittorio Giovannetti; Stefano Mancini

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We introduce a general model for a lossy bosonic memory channel and calculate the classical and the quantum capacity, proving that coherent state encoding is optimal. The use of a proper set of collective field variables allows to unravel the memory, showing that the n-fold concatenation of the memory channel is unitarily equivalent to the direct product of n single-mode lossy bosonic channels.

Source: http://arxiv.org/abs/0903.2764v1

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Sep 21, 2013
09/13

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L. Dunne; R. J. Ivison; S. Maddox; M. Cirasuolo; A. M. Mortier; S. Foucaud; E. Ibar; O. Almaini; C. Simpson; R. McLure

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We have studied the uJy radio properties of K-selected galaxies detected in the Ultra-Deep Survey portion of UKIDSS using 610- and 1,400-MHz images from the VLA and GMRT. These deep radio mosaics, combined with the largest and deepest K image currently available, allow high-S/N detections of many K-selected sub-populations, including sBzK and pBzK star-forming and passive galaxies. We find a strong correlation between the radio and K fluxes and a linear relationship between SFR and K...

Source: http://arxiv.org/abs/0808.3139v2

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Sep 21, 2013
09/13

by
A. K. Kwasniewski

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The way to arrive at formula of zeta matrix for any graded posets with the finite set of minimal elements is delivered following the first reference. This is being achieved via adjacency and zeta matrix description of bipartite digraphs chains, the representatives of graded posets. The bipartite digraphs elements of such chains amalgamate to form corresponding cover relation graded poset digraphs with corresponding adjacency matrices being amalgamated throughout natural join as special adequate...

Source: http://arxiv.org/abs/0901.0155v2

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Sep 23, 2013
09/13

by
L. R. Bedin; M. Salaris; G. Piotto; J. Anderson; I. R. King; S. Cassisi

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We use 14 orbits of ACS observations to reach the end of the white-dwarf cooling sequence in the globular cluster M4. Our photometry and completeness tests show that the end is located at magnitude m_F606W = 28.5+/-0.1, which implies an age of 11.6+/-0.6 Gyr (internal errors only). This is consistent with the age from fits to the main sequence turn-off (12.0+/-1.4 Gyr).

Source: http://arxiv.org/abs/0903.2839v1

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Sep 23, 2013
09/13

by
A. Morozov; Sh. Shakirov

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The simplest partition function, associated with homogeneous symmetric forms S of degree r in n variables, is integral discriminant J_{n|r}(S) = \int e^{-S(x_1 ... x_n)} dx_1 ... dx_n. Actually, S-dependence remains the same if e^{-S} in the integrand is substituted by arbitrary function f(S), i.e. integral discriminant is a characteristic of the form S itself, and not of the averaging procedure. The aim of the present paper is to calculate J_{n|r} in a number of non-Gaussian cases. Using Ward...

Source: http://arxiv.org/abs/0903.2595v1

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Sep 22, 2013
09/13

by
Sergio Gomez; Pablo Jensen; Alex Arenas

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We present a reformulation of modularity that allows the analysis of the community structure in networks of correlated data. The new modularity preserves the probabilistic semantics of the original definition even when the network is directed, weighted, signed, and has self-loops. This is the most general condition one can find in the study of any network, in particular those defined from correlated data. We apply our results to a real network of correlated data between stores in the city of...

Source: http://arxiv.org/abs/0812.3030v2

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Sep 18, 2013
09/13

by
Hamid R. Molavian; Michel J. P. Gingras

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Despite a Curie-Weiss temperature $\theta_{\rm CW} \sim -14$ K, the Tb2Ti2O7 pyrochlore magnetic material lacks long range magnetic order down to at least $T^*\approx 50$ mK. It has recently been proposed that the low temperature collective paramagnetic or spin liquid regime of this material may be akin to a spin ice state subject to both thermal and quantum fluctuations $-$ a {\it quantum spin ice} (QSI) of sorts. Here we explore the effect of a magnetic field ${\bm B}$ along the $[111]$...

Source: http://arxiv.org/abs/0809.3477v2

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Sep 23, 2013
09/13

by
Shirley Ho; Simon Dedeo; David Spergel

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We present a new method for detecting the missing baryons by generating a template for the kinematic Sunyaev-Zel'dovich effect. The template is computed from the product of a reconstructed velocity field with a galaxy field; we find that the combination of a galaxy redshift survey such as SDSS and a CMB survey such as ACT and PLANCK can detect the kSZ, and thus the ionized gas, at significant signal-to-noise. Unlike other techniques that look for hot gas or metals, this approach directly...

Source: http://arxiv.org/abs/0903.2845v1

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Sep 23, 2013
09/13

by
Helmut Satz

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Quantum chromodynamics predicts that the interaction between its fundamental constituents, quarks and gluons, can lead to different states of strongly interacting matter, dependent on its temperature and baryon density. We first survey the possible states of matter in QCD and discuss the transition from a color-confining hadronic phase to a plasma of deconfined colored quarks and gluons. Next, we summarize the results from non-perturbative studies of QCD at finite temperature and baryon...

Source: http://arxiv.org/abs/0903.2778v1

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Sep 23, 2013
09/13

by
K. Sakkos; J. Casulleras; J. Boronat

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High order actions proposed by Chin have been used for the first time in path integral Monte Carlo simulations. Contrarily to the Takahashi-Imada action, which is accurate to fourth order only for the trace, the Chin action is fully fourth order, with the additional advantage that the leading fourth and sixth order error coefficients are finely tunable. By optimizing two free parameters entering in the new action we show that the time step error dependence achieved is best fitted with a sixth...

Source: http://arxiv.org/abs/0903.2763v1

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Sep 23, 2013
09/13

by
Rainer M. Buchholz; Rainer Schödel; Andreas Eckart

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The goals of this work are to develop a new method to separate early and late type stellar components of a dense stellar cluster based on narrow band filters, to apply it to the central parsec of the GC, and to conduct a population analysis of this area. We use AO assisted observations obtained at the ESO VLT in the NIR H-band and 7 intermediate bands covering the NIR K-band. A comparison of the resulting SEDs with a blackbody of variable extinction then allows us to determine the presence and...

Source: http://arxiv.org/abs/0903.2135v2

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Sep 22, 2013
09/13

by
HERA-B Collaboration

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Inclusive doubly differential cross sections d^2\sigma_{pA}/dx_Fdp_T^2 as a function of Feynman-x (x_F) and transverse momentum (p_T) for the production of K^0_s, Lambda^0 and anti-Lambda^0 in proton-nucleus interactions at 920 GeV are presented. The measurements were performed by HERA-B in the negative x_F range (-0.12

Source: http://arxiv.org/abs/0812.0471v2

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Sep 23, 2013
09/13

by
Arie Leizarowitz

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The paper is concerned with estimating the number of integers smaller than $x$ whose largest prime divisor is smaller than $y$, denoted $\psi (x,y)$. Much of the related literature is concerned with approximating $\psi (x,y)$ by Dickman's function $\rho (u)$, where $u=\ln x/\ln y$. A typical such result is that $$ \psi (x,y)=x\rho (u)(1+o(1)) \eqno (1) $$ in a certain domain of the parameters $x$ and $y$. In this paper a different type of approximation of $\psi (x,y)$, using iterated logarithms...

Source: http://arxiv.org/abs/0903.2712v1

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Sep 23, 2013
09/13

by
Y. J. Uemura

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Recent muon and neutron experiments on the new FeAs-based superconductors revealed phase diagrams characterized by first-order evolution from antiferromagnetic to superconducting states, and an inelastic magnetic resonance mode whose energy scales as $\sim 4 k_{B}T_{c}$. These features exhibit striking commonalities with cuprate, backyball, organic, and heavy-fermion superconductors as well as superfluid $^{4}$He.

Source: http://arxiv.org/abs/0903.2758v1

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Sep 18, 2013
09/13

by
Martin Lorenz

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Let G be an affine algebraic group and let R be an associative algebra with a rational action of G by algebra automorphisms. We study the induced G-action on the spectrum Spec R of all prime ideals of R, viewed as a topological space with the Jacobson-Zariski topology, and on the subspace consisting of all rational ideals of R. Here, a prime ideal P of R is said to be rational if the extended centroid of R/P is equal to the base field. The main themes of the article are local closedness of...

Source: http://arxiv.org/abs/0809.5205v2

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Sep 23, 2013
09/13

by
G. Hector; E. Macías-Virgós; E. Sanmartín-Carbón

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Let $(M,\mathcal{F})$ be a foliated manifold. We prove that there is a canonical isomorphism between the complex of base-like forms $\Omega^*_b(M,\mathcal{F})$ of the foliation and the "De Rham complex" of the space of leaves $M/\mathcal{F}$ when considered as a "diffeological" quotient. Consequently, the two corresponding cohomology groups $H^*_b(M,\mathcal{F})$ and $H^*(M/\mathcal{F})$ are isomorphic.

Source: http://arxiv.org/abs/0903.2871v1

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Sep 21, 2013
09/13

by
A. Yamasaki; S. Imada; K. Takase; T. Muro; Y. Kato; H. Kobori; A. Sugimura; N. Umeyama; H. Sato; Y. Hara; N. Miyakawa; S. I. Ikeda

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We have investigated the electronic structures of newly discovered superconductor FeSe1-x by bulk-sensitive photoemission spectroscopy (PES). The large Fe 3d spectral weight is located in the vicinity of the Fermi level (EF) and it decreases steeply toward EF . Compared with results of band structure calculations, narrowing the Fe 3d band width and the energy shift of the band toward EF are found, suggesting a mass enhancement due to the weak electron correlation effect. Meanwhile, Fe 2p...

Source: http://arxiv.org/abs/0902.3314v3

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Sep 23, 2013
09/13

by
M. Battaglia; L. Fletcher; A. O. Benz

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In the classical flare picture, hard X-ray emission from the chromosphere is succeeded by soft-X-ray emission from hot plasma in the flare loop, the soft X-ray emission being a direct consequence of the impact of the non-thermal particle beam. However, observations of events exist in which a pronounced increase in soft X-ray emission is observed minutes before the onset of the hard X-ray emission. Such pre-flare emission clearly contradicts the classical flare picture. For the first time, the...

Source: http://arxiv.org/abs/0903.2754v1

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Sep 23, 2013
09/13

by
Babak Vakili

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The effects of noncommutativity and deformed Heisenberg algebra on the evolution of a two dimensional minisuperspace quantum cosmological model are investigated.

Source: http://arxiv.org/abs/0903.2789v1

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Sep 23, 2013
09/13

by
Hans-Joachim Baues

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We describe a conjecture on the algebra of higher cohomology operations which leads to the computations of the differentials in the Adams spectral sequence. For this we introduce the notion of an n-th order track category which is suitable to study higher order Toda brackets and the differentials in spectral sequences. We describe various examples of higher order track categories which are topological, in particular the track category of higher cohomology operations. Also differential algebras...

Source: http://arxiv.org/abs/0903.2876v1

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Sep 23, 2013
09/13

by
T. Fujita; M. B. A. Jalil; S. G. Tan

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A semi-classical description of the intrinsic spin-Hall effect (SHE) is presented which is relevant for a wide class of systems. A heuristic model for the SHE is developed, starting with a fully quantum mechanical treatment, from which we construct an intuitive expression for the spin-Hall current and conductivity. Our method makes transparent the physical mechanism which drives the effect, and unifies the SHE across several spintronic and optical systems. Finally, we propose an analogous...

Source: http://arxiv.org/abs/0903.2702v1

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Sep 23, 2013
09/13

by
Frans Snik

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Many objects on the sky exhibit a centrosymmetric polarization pattern, particularly in cases involving single scattering around a central source. Utilizing a novel liquid crystal device (the ``theta cell'') that transforms the coordinate system of linear polarization in an image plane from Cartesian to polar, the observation of centrosymmetric polarization patterns can be improved: instead of measuring Stokes Q and U on the sky, one only needs to measure Stokes Q' in the new instrument...

Source: http://arxiv.org/abs/0903.2734v1

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Sep 18, 2013
09/13

by
Franziska Synatschke; Georg Bergner; Holger Gies; Andreas Wipf

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We study supersymmetric quantum mechanics with the functional RG formulated in terms of an exact and manifestly off-shell supersymmetric flow equation for the effective action. We solve the flow equation nonperturbatively in a systematic super-covariant derivative expansion and concentrate on systems with unbroken supersymmetry. Already at next-to-leading order, the energy of the first excited state for convex potentials is accurately determined within a 1% error for a wide range of couplings...

Source: http://arxiv.org/abs/0809.4396v2

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Sep 22, 2013
09/13

by
Andreas Luscher; Andreas Laeuchli

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We study the field dependence of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice by means of exact diagonalizations. In a first part, we calculate the spin-wave velocity, the spin-stiffness, and the magnetic susceptibility and thus determine the microscopic parameters of the low-energy long-wavelength description. In a second part, we present a comprehensive study of dynamical spin correlation functions for magnetic fields ranging from zero up to saturation. We find that...

Source: http://arxiv.org/abs/0812.3420v3

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Sep 23, 2013
09/13

by
Alexander John; Andreas Schadschneider; Debashish Chowdhury; Katsuhiro Nishinari

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We report experimental results on unidirectional traffic-like collective movement of ants on trails. Our work is primarily motivated by fundamental questions on the collective spatio-temporal organization in systems of interacting motile constituents driven far from equilibrium. Making use of the analogies with vehicular traffic, we analyze our experimental data for the spatio-temporal organisation of the ants on the trail. From this analysis, we extract the flow-density relation as well as the...

Source: http://arxiv.org/abs/0903.2717v1

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Sep 23, 2013
09/13

by
Daniel A Spielman; Jaeoh Woo

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Boman and Hendrickson observed that one can solve linear systems in Laplacian matrices in time $\bigO{m^{3/2 + o (1)} \ln (1/\epsilon)}$ by preconditioning with the Laplacian of a low-stretch spanning tree. By examining the distribution of eigenvalues of the preconditioned linear system, we prove that the preconditioned conjugate gradient will actually solve the linear system in time $\softO{m^{4/3} \ln (1/\epsilon)}$.

Source: http://arxiv.org/abs/0903.2816v1

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Sep 23, 2013
09/13

by
Najib Mahdou; Mohammed Tamekkante; Siamak Yassemi

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We compute the Gorenstein weak dimension of a coherent power series rings over a commutative rings and we show that, in general, $\gwd(R) \leq 1$ does not imply that $R$ is an arithmetical ring.

Source: http://arxiv.org/abs/0903.2779v1

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Sep 23, 2013
09/13

by
Satyan L. Devadoss; Rahul Shah; Xuancheng Shao; Ezra Winston

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The associahedron is a convex polytope whose face poset is based on nonintersecting diagonals of a convex polygon. In this paper, given an arbitrary simple polygon P, we construct a polytopal complex analogous to the associahedron based on convex diagonalizations of P. We describe topological properties of this complex and provide realizations based on secondary polytopes. Moreover, using the visibility graph of P, a deformation space of polygons is created which encapsulates substructures of...

Source: http://arxiv.org/abs/0903.2848v1

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Jul 20, 2013
07/13

by
L. Herrera; A. Di Prisco; E. Fuenmayor; O. Troconis

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The Misner and Sharp approach to the study of gravitational collapse is extended to the viscous dissipative case in, both, the streaming out and the diffusion approximations. The dynamical equation is then coupled to causal transport equations for the heat flux, the shear and the bulk viscosity, in the context of Israel--Stewart theory, without excluding the thermodynamics viscous/heat coupling coefficients. The result is compared with previous works where these later coefficients were...

Source: http://arxiv.org/abs/0804.3584v2

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Sep 23, 2013
09/13

by
Sergio Lopez-Permouth; Steve Szabo

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Repeated root Cyclic and Negacyclic codes over Galois rings have been studied much less than their simple root counterparts. This situation is beginning to change. For example, repeated root codes of length $p^s$, where $p$ is the characteristic of the alphabet ring, have been studied under some additional hypotheses. In each one of those cases, the ambient space for the codes has turned out to be a chain ring. In this paper, all remaining cases of cyclic and negacyclic codes of length $p^s$...

Source: http://arxiv.org/abs/0903.2791v1

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Sep 18, 2013
09/13

by
Josef Ludescher; Ralf Hofmann

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Based on the postulate that photon propagation is governed by an SU(2) gauge principle we numerically compute the one-loop dispersion for thermalized photon propagation on the radiatively induced mass shell. Formerly, the dispersion was addressed by assuming $p^2=0$. While this approximation turns out to be excellent for temperatures $\le 2 T_{\tiny{CMB}}$ the exact result exhibits a much faster (power-like) shrinking of the gap in the black-body spectral intensity with rising temperature. Our...

Source: http://arxiv.org/abs/0806.0972v2

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Sep 23, 2013
09/13

by
Chris Orum; Cliff A Joslyn

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We extend the definitions of upper and lower valuations on partially ordered sets, and consider the metrics they induce, in particular the metrics available (or not) based on the logarithms of such valuations. Motivating applications in computational linguistics and computational biology are indicated.

Source: http://arxiv.org/abs/0903.2679v1

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Sep 23, 2013
09/13

by
Daniele Colosi

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We quantize a real massive Klein-Gordon field in curved spacetimes within the general boundary formulation. The vacuum wave function is given by a Gaussian in the Schr\"odinger representation and we study the general structure of the operator appearing in the Gaussian. We show that it obeys a Riccati equation and we provide the general solution.

Source: http://arxiv.org/abs/0903.2476v1

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Sep 21, 2013
09/13

by
C. Bogdanos; A. Dimitriadis; K. Tamvakis

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We consider 5D braneworld models of quasi-localized gravity in which 4D gravity is reproduced at intermediate scales while the extra dimension opens up at both the very short and the very long distances, where the geometry is flat. Our main interest is the interplay between the zero mode of these models, whenever a normalizable zero mode exists, and the effects of zero energy graviton resonant modes coming from the contributions of massive KK modes. We first consider a compactified version of...

Source: http://arxiv.org/abs/0706.1015v2

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Sep 23, 2013
09/13

by
S. Gandolfi; A. Yu. Illarionov; K. E. Schmidt; F. Pederiva; S. Fantoni

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We calculate the equation of state of neutron matter at zero temperature by means of the auxiliary field diffusion Monte Carlo method (AFDMC) combined with a fixed-phase approximation. The calculation of the energy is carried out by simulating up to 114 neutrons in a periodic box. Special attention was made to reduce finite size effects at the energy evaluation by adding to the interaction the effect due to the truncation of the simulation box, and by performing several simulations using...

Source: http://arxiv.org/abs/0903.2610v1

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Sep 23, 2013
09/13

by
T. T. Heikkila; F. Giazotto

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We study the role of the superconducting proximity effect on the electron-phonon energy exchange in diffusive normal metals (N) attached to superconductors (S). The proximity effect modifies the spectral response of the normal metal, in particular the local density of states. This leads to a weakening of the electron-phonon energy relaxation. We show that the effect is easily observable with modern thermometry methods, and predict that it can be tuned in structures connected to multiple...

Source: http://arxiv.org/abs/0810.4843v2

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Sep 22, 2013
09/13

by
Ayse Arslanargin; Ali Kaya

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We consider early time cosmic evolution in string gas cosmology dominated by open strings attached to D-branes. After reviewing statistical properties of open strings in D-brane backgrounds, we use dilaton-gravity equations to determine the string frame fields. Although, there are distinctions in the Hagedorn regime thermodynamics and dilaton coupling as compared to closed strings, it seems difficult to avoid Jeans instability and assume thermal equilibrium simultaneously, which is already a...

Source: http://arxiv.org/abs/0901.4608v2

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Sep 23, 2013
09/13

by
Paul Kessenich

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Global existence for a system of nonlinear partial differential equations (PDE) modeling an isotropic incompressible viscoelastic material is proved. The structure of the PDE is derived through constitutive assumptions on the material. Restriction on the size of the initial displacement and velocity for the model is specified independent of the size of the viscosity of the material. The proof of global existence combines use of vector fields, local energy decay estimates, generalized Sobolev...

Source: http://arxiv.org/abs/0903.2824v1

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Sep 23, 2013
09/13

by
Vincent Beck

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Let $\Ascr,\Bscr$ be exact categories with $\Ascr$ karoubian and $M$ be an exact functor. Under suitable adjonction hypotheses for $M$, we are able to show that the direct factors of the objects of $\Ascr$ of the form $MY$ with $Y \in \Bscr$ make up a Frobenius category which allow us to define an $M$-stable category for $\Ascr$ only by quotienting. In addition, we propose a construction of an $M$-stable category for $\Ascr,\Bscr$ triangulated categories and $M$ a triangulated functor. We...

Source: http://arxiv.org/abs/0903.2868v1

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Sep 21, 2013
09/13

by
Fabio Riccioni; Peter West

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We give a method of deriving the field-strengths of all massless and massive maximal supergravity theories in any dimension starting from the Kac-Moody algebra $E_{11}$. Considering the subalgebra of $E_{11}$ that acts on the fields in the non-linear realisation as a global symmetry, we show how this is promoted to a gauge symmetry enlarging the algebra by the inclusion of additional generators. We show how this works in eleven dimensions, and we call the resulting enlarged algebra...

Source: http://arxiv.org/abs/0902.4678v2

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Sep 23, 2013
09/13

by
Ties Behnke; Klaus Dehmelt; Takeshi Matsuda; Peter Schade

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The use of a TPC in future collider experiments needs significant research and development. Within the EUDET program an infrastructure has been designed and built to allow the efficient testing of TPC prototypes under realistic conditions. The infrastructure consists of a test beam facility, located at DESY Hamburg, and a multi-purpose TPC field cage.

Source: http://arxiv.org/abs/0903.2803v1

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Sep 23, 2013
09/13

by
Brent C. Melot; Brian Paden; Ram Seshadri; Ambesh Dixit; Gavin Lawes; Emmanuelle Suard

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CoSe$_2$O$_5$ has a crystal structure consisting of zig-zag chains of edge shared CoO$_6$ octahedra running along the c axis, with the chains separated by Se$_2$O$_5^{2-}$ units. Magnetic susceptibility measurements indicate a transition at 8.5 K to an ordered state. We investigate here the nature of this magnetic ordering using magnetization and specific heat measurements in addition to powder neuttron diffraction. A transition to long-range antiferromagnetic order is found below $T_N$ = 8.5 K...

Source: http://arxiv.org/abs/0903.2513v1

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Sep 23, 2013
09/13

by
Hichem Hajaiej

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We prove the uniqueness of the maximizers of a Hardy-Littlewood type functional under constraints. We also establish a quantitative stability estimate. Introduction

Source: http://arxiv.org/abs/0903.2826v1

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Sep 23, 2013
09/13

by
P. Di Matteo; A. Pipino; M. D. Lehnert; F. Combes; B. Semelin

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Using a large suite of galaxies with a variety of concentrations and metallicity gradients, we study the evolution of non-dissipative ("dry") equal mass mergers. Our purpose in generating these simulations is to explore how the metallicity gradient in dry mergers depends on the structure and metallicity gradients of the galaxies involved in the merger. Specifically, we would like to answer: Could dry mergers lead to metallicity gradients as observed in elliptical galaxies in the local...

Source: http://arxiv.org/abs/0903.2846v1

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Sep 19, 2013
09/13

by
Matthias Kuenzer

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We show by an example that in a Verdier triangulated category, there may exist two mutually nonisomorphic Verdier octahedra containing the same commutative triangle.

Source: http://arxiv.org/abs/0708.0151v4

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Sep 22, 2013
09/13

by
L. Qian; M. A. Abramowicz; P. C. Fragile; J. Horak; M. Machida; O. Straub

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We construct a new family of analytic models of black hole accretion disks in dynamical equilibria. Our construction is based on assuming distributions of angular momentum and entropy. For a particular choice of the distribution of angular momentum, we calculate the shapes of equipressure surfaces. The equipressure surfaces we find are similar to those in thick, slim and thin disks, and to those in ADAFs.

Source: http://arxiv.org/abs/0812.2467v2

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51

Sep 23, 2013
09/13

by
Jean-Francois Clément; Jean-Philippe Brantut; Martin Robert De Saint Vincent; Robert A. Nyman; A. Aspect; Thomas Bourdel; Philippe Bouyer

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We demonstrate runaway evaporative cooling directly with a tightly confining optical dipole trap and achieve fast production of condensates of 1.5x10^5 87Rb atoms. Our scheme is characterized by an independent control of the optical trap confinement and depth, permitting forced evaporative cooling without reducing the trap stiffness. Although our configuration is particularly well suited to the case of 87Rb atoms in a 1565nm optical trap, where an efficient initial loading is possible, our...

Source: http://arxiv.org/abs/0903.2745v1

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28

Sep 23, 2013
09/13

by
Tadeusz Iwaniec; Leonid V. Kovalev; Jani Onninen

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As long ago as 1962 Nitsche conjectured that a harmonic homeomorphism $h \colon A(r,R) \to A(r_*, R_*)$ between planar annuli exists if and only if $\frac{R_*}{r_*} \ge {1/2} (\frac{R}{r} + \frac{r}{R})$. We prove this conjecture when the domain annulus is not too wide; explicitly, when $\log \frac{R}{r} \le {3/2}$. For general $A(r,R)$ the conjecture is proved under additional assumption that either $h$ or its normal derivative have vanishing average on the inner boundary circle. This is the...

Source: http://arxiv.org/abs/0903.2665v1

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42

Sep 23, 2013
09/13

by
J. P. May

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The construction of E infinity ring spaces and thus E infinity ring spectra from bipermutative categories gives the most highly structured way of obtaining the K-theory commutative ring spectra. The original construction dates from around 1980 and has never been superseded, but the original details are difficult, obscure, and slightly wrong. We rework the construction in a much more elementary fashion.

Source: http://arxiv.org/abs/0903.2818v1