August 2005 arXiv papers — page 8

Augustin-Liviu Mare

Let $P=G/K$ be a semisimple non-compact Riemannian symmetric space, where $G=I_0(P)$ and $K=G_p$ is the stabilizer of $p\in P$. Let $X$ be an orbit of the (isotropy) representation of $K$ on $T_p(P)$ ($X$ is called a real flag manifold). Let $K_0\subset K$ be the stabilizer of a maximal flat, totally geodesic submanifold of $P$ which contains $p$. We show th

J. M. Marco, J. Parcet

Let $Ω$ be a vector space over a finite field with q elements. Let G denote the general linear group of endomorphisms of $Ω$ and let us consider the left regular representation $ρ: G \to B(L_2(X))$ associated to the natural action of G on the set X of linear subspaces of $Ω$. In this paper we study a natural basis B of the algebra $End_{G}(L_2(X))$ of intert

Alexandru Oancea

We prove the Kunneth formula in Floer (co)homology for manifolds with restricted contact type boundary. We use Viterbo's definition of Floer homology, involving the symplectic completion by adding a positive cone over the boundary. The Kunneth formula implies the vanishing of Floer (co)homology for subcritical Stein manifolds. Other applications include

Javier Parcet, Gilles Pisier

Let $\Free_n$ denote the free group with $n$ generators $g_1, g_2, ..., g_n$. Let $λ$ stand for the left regular representation of $\Free_n$ and let $τ$ be the standard trace associated to $λ$. Given any positive integer $d$, we study the operator space structure of the subspace $\Word_p(n,d)$ of $L_p(τ)$ generated by the family of operators $λ(g_{i_1}g_{i_2

José Manuel Marco, Javier Parcet

An analogue of Taylor's formula, which arises by substituting the classical derivative by a divided difference operator of Askey-Wilson type, is developed here. We study the convergence of the associated Taylor series. Our results complement a recent work by Ismail and Stanton. Quite surprisingly, in some cases the Taylor polynomials converge to a functi

Farrell Brumley

We establish zero-free regions tapering as an inverse power of the analytic conductor for Rankin-Selberg L-functions on GL(n) x GL(n'). Such zero-free regions are equivalent to commensurate lower bounds on the edge of the critical strip, and in the case of $L(s,f x f~), on the residue at s=1. As an application we show that a cuspidal automorphic represen

O. Lauscher, M. Reuter

Four-dimensional Quantum Einstein Gravity (QEG) is likely to be an asymptotically safe theory which is applicable at arbitrarily small distance scales. On sub-Planckian distances it predicts that spacetime is a fractal with an effective dimensionality of 2. The original argument leading to this result was based upon the anomalous dimension of Newton's co

R. Clarkson, R. B. Mann

We present a new class of solutions in odd dimensions to Einstein's equations containing either a positive or negative cosmological constant. These solutions resemble the even-dimensional Eguchi-Hanson-(A)dS metrics, with the added feature of having Lorentzian signatures. They are asymptotic to (A)dS$_{d+1}/Z_p$. In the AdS case their energy is negative

Athanasios Prikas

In the present work we investigate the existence and stability properties of q-balls which consist of a couple of scalar fields, forming an SU(2) doublet in a Lagrangian with a global SU(2) symmetry. We find that these spinors can form a localized and stable field configuration, if they rotate in their internal SU(2) space. We find the energy and charge of t

P. Bozhilov

Motivated by the recent achievements in the framework of the semiclassical limit of the M-theory/field theory correspondence, we propose an approach for obtaining exact membrane solutions in general enough M-theory backgrounds, having field theory dual description. As an application of the derived general results, we obtain several types of membrane solution

B. Z. Kopeliovich, I. K. Potashnikova, Ivan Schmidt

The cross sections for a variety of channels of proton-nucleus interaction associated with large gaps in rapidity are calculated within the Glauber-Gribov theory. We found inelastic shadowing corrections to be dramatically enhanced for such events. We employ the light-cone dipole formalism which allows to calculate the inelastic corrections to all orders of

M. S. Kugeratski, V. P. Goncalves, F. S. Navarra

Perturbative Quantum Chromodynamics (pQCD) predicts that the small-$x$ gluons in a hadron wavefunction should form a Color Glass Condensate (CGC), which has universal properties, which are the same for all hadrons or nuclei. Assuming this property, in this paper we cross relate the current CGC descriptions of the $ep$ HERA data and $dAu$ RHIC data. In partic

J. R. Forshaw

We review the calculation for Higgs production via the exclusive reaction pp -> p+H+p. In the first part we review in some detail the calculation of the Durham group and emphasise the main areas of uncertainty. Afterwards, we comment upon other calculations.

A. Tawfik

It is shown that the freezeout parameters estimated in the heavy-ion collisions all are well described by a constant value of the entropy density $s$ divided by $T^3$. The value of $s/T^3$ has been taken from the lattice QCD simulations at zero baryo-chemical potential $μ_B$ and assumed to remain constant for finite $μ_B$. This implies that the hadronic matt

V. G. Baryshevsky

The T-odd phenomenon of induction of the magnetic field by a static electric field provides to study the electron EDM and constants of T-odd, P-odd interaction of an electron with a nucleus. Measurement of this magnetic field for ferroelectric materials (like PbTiO_3) at the level B~3 10^{-18} G allows to derive the electric dipole moment of an electron at t

A. Bottino, F. Donato, N. Fornengo, S. Scopel

New upper bounds on direct detection rates have recently been presented by a number of experimental collaborations working on searches for WIMPs. In this paper we analyze how the constraints on relic neutralinos which can be derived from these results is affected by the uncertainties in the distribution function of WIMPs in the halo. Various different catego

Shengqin Feng, Xianbao Yuan, Yafei Shi

We study the production of proton, antiproton and net-proton at \AGS, \SPS and \RHIC within the framework non-uniform flow model(NUFM) in this paper. It is found that the system of RHIC has stronger longitudinally non-uniform feature than AGS and SPS, which means that nuclei at RHIC energy region is much more transparent. The NUFM model provides a very good

G. G. Kirilin

In this paper we study the semileptonic decay $B\toπl ν$ and in particular the factorizable contribution to symmetry breaking corrections to the form factors at large recoil. This contribution is a convolution of the coefficient function, which can be calculated in perturbation theory, and of the nonperturbative light-cone distribution amplitudes of the meso

Stefan Schaefer, Thomas DeGrand

We summarize our recent investigations of lattice QCD with dynamical overlap fermions. We sketch algorithmic issues and our approach to solving them. We show our measurement of the topological susceptibility. We describe a computation of the chiral condensate using an analysis of the distribution of eigenmodes of the Dirac operator and Random Matrix Theory.

Xiang-Qian Luo

One of the most challenging issues in QCD is the investigation of spontaneous chiral-symmetry breaking, which is characterized by the non-vanishing chiral condensate when the bare fermion mass is zero. In standard methods, one has to perform expensive lattice simulations at multiple bare quark masses, and employ some modeled function to extrapolate the data

The Belle Collaboration

We report improved measurements of B to pseudoscalar-vector decays containing an omega meson in the final state. These results are obtained from a data sample that contains 386 millions BBbar pairs collected at the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric energy e^+e^- collider. We measure the branching fractions Br(B^+/- -> omeg

Fay Dowker

The causal set approach to quantum gravity embodies the concepts of causality and discreteness. This article explores some foundational and conceptual issues within causal set theory.

Carlo Rovelli, Simone Speziale

The idea of treating general relativistic theories in a perturbative expansion around a topological theory has been recently put forward in the quantum gravity literature. Here we investigate the viability of this idea, by applying it to conventional Yang--Mills theory on flat spacetime. We find that the expansion around the topological theory coincides with

J. Ellis, N. E. Mavromatos, M. Westmuckett, D. V. Nanopoulos

We discuss cosmology in the context of Liouville strings, characterized by a central-charge deficit Q^2, in which target time is identified with (the world-sheet zero mode of the) Liouville field: Q-Cosmology. We use a specific example of colliding brane worlds to illustrate the phase diagram of this cosmological framework. The collision provides the necessa

Charles H. -T. Wang

We present a parameter-free gauge formulation of general relativity in terms of a new set of real spin connection variables. The theory is constructed by extending the phase space of the recently formulated conformal geometrodynamics for canonical gravity to accommodate a spin gauge description. This leads to a further enlarged set of first class gravitation

Gennady P. Berman, Vyacheslav N. Gorshkov, Edward P. MacKerrow, Xidi Wang

A high-performance algorithm for searching for frequent patterns (FPs) in transactional databases is presented. The search for FPs is carried out by using an iterative sieve algorithm by computing the set of enclosed cycles. In each inner cycle of level FPs composed of elements are generated. The assigned number of enclosed cycles (the parameter of the probl

Soumya Jana

In the first paper of this two part communication, we solved in a unified framework a variety of two terminal source coding problems with noncooperative encoders, thereby consolidating works of Shannon, Slepian-Wolf, Wyner, Ahlswede-Körner, Wyner-Ziv, Berger {\em et al.} and Berger-Yeung. To achieve such unification we made use of a fundamental principle tha

Xi Shen, Philippe De Wilde

We report the first results of simulating the coupling of neuronal, astrocyte, and cerebrovascular activity. It is suggested that the dynamics of the system is different from systems that only include neurons. In the neuron-vascular coupling, distribution of synapse strengths affects neuronal behavior and thus balance of the blood flow; oscillations are indu

K. -W. Lee, W. E. Pickett

We present results of studies of charge disproportionation (CD) and spin differentiation in Na$_x$CoO$_2$ using the correlated band theory approach (local-density approximation+Hubbard U:LDA+U). The simultaneous CD and gap opening can be followed through a first order charge disproportionation transition. By comparison with experiments, we propose a value of

Murilo L. Tiago, James R. Chelikowsky

We present a first-principles method for the calculation of optical excitations in nanosystems. The method is based on solving the Bethe-Salpeter equation (BSE) for neutral excitations. The electron self-energy is evaluated within the GW approximation, with dynamical screening effects described within time-dependent density-functional theory in the adiabatic

A. V. Chubukov, T. P. Devereaux, M. V. Klein

We argue that Raman scattering in $B_{1g}$ symmetry allows one to distinguish between phonon-mediated and magnetically-mediated $d-$wave superconductivity. In spin mediated superconductors, $B_{1g}$ Raman intensity develops a resonance at a frequency $ω_{res} < 2Δ_{max}$, whose origin is similar to a neutron resonance. In phonon-mediated $d-$wave superconduc

Patrick Bruno, Vitalii K. Dugaev

We discuss the problem of equilibrium spin currents in ferromagnets with inhomogeneous magnetization. Using simple microscopic models we explain the physical origin of equilibrium spin currents. Next we derive the equilibrium spin current from the Hamiltonian with a gauge field associated with local rotations in the spin space. Several examples of magnetic s

Ying Jiang, Thorsten Emig

A systematic study of both classical and quantum geometric frustrated Ising models with a competing ordering mechanism is reported in this paper. The ordering comes in the classical case from a coupling of 2D layers and in the quantum model from the quantum dynamics induced by a transverse field. By mapping the Ising models on a triangular lattice to elastic

Andrea Rapisarda, Alessandro Pluchino

An instructive and apparently simple model of fully-coupled rotators, the so-called Hamiltonian Mean Field (HMF) model, together with a generalized version with variable interaction range, have revealed a very complex out-of-equilibrium dynamics which can be considered paradigmatic for nonextensive systems. In this short paper we illustrate the interesting a

A. Tillmanns, S. Oertker, B. Beschoten, G. Güntherodt

The asymmetric magnetization reversal in exchange biased Fe/MnF$_{2}$ involves coherent (Stoner-Wohlfarth) magnetization rotation into an intermediate, stable state perpendicular to the applied field. We provide here experimentally tested analytical conditions for the unambiguous observation of both longitudinal and transverse magnetization components using

N. Aliouane, D. N. Argyriou, J. Strempfer, I. Zegkinoglou

We have used in-field neutron and X-ray single crystal diffraction to measure the incommensurability &#948; of the crystal and magnetic structure of multiferroic TbMnO3 . We show that the flop in the electric polarization at the critical field HC, for field H along the a&#8722; and b&#8722;axis coincides with a 1st order transition to a commensurate phase wi

Takashi Odagaki, Tsuyoshi Okubo, Ryusei Ogata, Keiji Okazaki

For the binary discs packed in two dimensions, the packing fraction of disc assembly becomes lower than that of the monodisperse system when the size ratio is close to unity. We show that the suppressed packing fraction is caused by an increase of the adjacent neighbours with long bonds where the adjacent neighbours is defined on the basis of the Laguerre (r

Ingve Simonsen

Over the last decade, an enormous interest and activity in complex networks have been witnessed within the physics community. On the other hand, diffusion and its theory, have equipped the toolbox of the physicist for decades. In this paper, we will demonstrate how to combine these two seemingly different topics in a fruitful manner. In particular, we will r

D. I. Khomskii

Rich properties of systems with strongly correlated electrons, such as transition metal oxides, is largely connected with an interplay of different degrees of freedom in them: charge, spin, orbital ones, as well as crystal lattice. Specific and often very important role is played by orbital degrees of freedom. In this comment I will shortly summarize the mai

N. H. Andersen, J. Jensen, T. B. S. Jensen, M. v. Zimmermann

We present synchrotron x-ray diffraction studies revealing that the lattice of thulium borocarbide is distorted below T_Q = 13.5 K at zero field. T_Q increases and the amplitude of the displacements is drastically enhanced, by a factor of 10 at 60 kOe, when a magnetic field is applied along [100]. The distortion occurs at the same wave vector as the antiferr

D. Marenduzzo, T. X. Hoang, F. Seno, M. Vendruscolo

Patterns and forms adopted by Nature, such as the shape of living cells, the geometry of shells and the branched structure of plants, are often the result of simple dynamical paradigms. Here we show that a growing self-interacting string attached to a tracking origin, modeled to resemble nascent polypeptides in vivo, develops helical structures which are mor

F. Luis, J. Campo, J. Gomez, G. J. McIntyre

We use neutron diffraction to probe the magnetization components of a crystal of Mn12 single-molecule magnets. Each of these molecules behaves, at low temperatures, as a nanomagnet with spin S = 10 and strong anisotropy along the crystallographic c axis. Application of a magnetic field perpendicular to c induces quantum tunneling between opposite spin orient

M. K. Chattopadhyay, S. B. Roy, P. Chaddah

We present results of dc magnetization and magnetic relaxation study showing the kinetic arrest of a first order ferromagnetic to antiferromagnetic transition in Ce(Fe$_{0.96}$Ru$_{0.04}$)$_2$. This leads to the formation of a non-ergodic glass-like magnetic state. The onset of the magnetic-glass transformation is tracked through the slowing down of the magn

N. Masuda, K. -I. Goh, B. Kahng

The Bak-Sneppen model displaying punctuated equilibria in biological evolution is studied on random complex networks. By using the rate equation and the random walk approaches, we obtain the analytic solution of the fitness threshold $x_c$ to be 1/(<k>_f+1), where <k>_f=<k^2>/<k> (=<k>) in the quenched (annealed) updating case, where <k^n> is the n-th moment

S. Ozcan, P. J. Turner, J. R. Waldram, R. J. Drost

Precise measurements of the in-plane microwave surface impedance of high-quality single crystals of Bi2212 and Tl2201 are used to probe the relaxation time of nodal quasiparticles in the d-wave superconducting state through a two-fluid analysis of the microwave conductivity. While this analysis requires us to posit a form for the frequency-dependent quasipar

K. Hijii, A. Kitazawa, K. Nomura

We investigate the ground state phase diagram of the S=1/2 two-leg $XXZ$ spin ladder system with an isotropic interchain coupling. In this model, there is the Berezinskii-Kosterlitz-Thouless transition which occurs at the XY-Haldane and the XY-rung singlet phase boundaries. It was difficult to determine the transition line using traditional methods. We overc

Akira Ueda, Shinji Takesue

We study heat conduction in one dimensional lattice dynamical systems far from equilibrium. The Fermi-Pasta-Ulam model and the $ϕ^4$ model are numerically compared to elucidate differences between momentum-conserving and nonconserving systems. As a results, it is found that the heat flux in the $ϕ^4$ model does not increase monotonically as the temperature d

A. B. Harris, G. Lawes

We review the phenomenology of coupled magnetic and electric order parameters for systems in which ferroelectric and incommensurate magnetic order occur simultaneously. We discuss the role that such materials might play in fabricating novel magnetoelectric devices. Then we briefly review the mean-field description of ferroelectricity and modulated magnetic o

Ying Zhang, S. Das Sarma

We show that 2D and 3D electron systems with the long-range Coulomb electron-electron interaction could develop ferromagnetic instabilities due to strong exchange effects at low densities. The critical densities in both 2D and 3D systems at which the magnetic instability, which could either be of Stoner type (second-order) or of Bloch type (first-order), are

Oleg G. Shpyrko, Alexei Yu. Grigoriev, Reinhard Streitel, Diego Pontoni

Resonant x-ray reflectivity of the surface of the liquid phase of the Bi$_{43}$Sn$_{57}$ eutectic alloy reveals atomic-scale demixing extending over three near-surface atomic layers. Due to the absence of underlying atomic lattice which typically defines adsorption in crystalline alloys, studies of adsorption in liquid alloys provide unique insight on intera

Peter Erwin

I present a study of the sizes (semimajor axes) of bars in disc galaxies, combining a detailed study of 65 S0-Sb galaxies with measurements of 70 Sb-Sd galaxies from Martin (1995). As has been noted before with smaller samples, bars in early-type (S0-Sb) galaxies are clearly larger than bars in late-type (Sc-Sd) galaxies; this is true both for relative sizes

Yutaka Fujita, Tsunehiko N. Kato

We propose that strong magnetic fields should be generated at shock waves associated with formation of galaxies or clusters of galaxies by the Weibel instability, an instability in collisionless plasmas. The strength of the magnetic fields generated through this mechanism is close to the order of those observed in galaxies or clusters of galaxies at present.

Megan Donahue, G. Mark Voit, Christopher P. O&#39;Dea, Stefi A. Baum

Radio lobes inflated by active galactic nuclei at the centers of clusters are a promising candidate for halting condensation in clusters with short central cooling times because they are common in such clusters. In order to test the AGN-heating hypothesis, we obtained Chandra observations of two clusters with short central cooling times yet no evidence for A

W. Bian

According to the standard model, an active galactic nucleus (AGN) consists of an inner accretion disk with a jet around a central massive black hole, and a number of outer broad line regions (BLRs) and narrow line regions (NLRs). The geometrical relationship between the BLRs and the accretion disk is not well understood. Assuming the motion of the BLRs is vi

P. D&#39;Avanzo, S. Campana, J. Casares, G. L. Israel

We present ESO-NTT low resolution spectroscopy of the neutron star X-ray transient Cen X-4 in quiescence over a complete orbital cycle. Our data reveal the presence of a K3-7 V companion which contributes 63% to the 5600-6900A flux and orbits the neutron star with a velocity semi-amplitude of K_2=145.8 +/- 1.0 km s^{-1}. This, combined with a previous determ

W. Bian

Using the H$β$ linewidth, we obtained the virial central supermassive black hole masses and then the Eddington ratios in a sample of broad-line AGNs and NLS1s observed by ASCA. Combined with the data from ROSAT and Chandra observations, We found a strong correlation between hard/soft X-ray photon index and the Eddington ratio. Such a correlation can be under

C. A. Goessl, J. Snigula, U. Hopp

Dwarf galaxies in the Local Group provide a unique astrophysical laboratory. Despite their proximity some of these systems still lack a reliable distance determination as well as studies of their stellar content and star formation history. We present first results of our survey of variable stars in a sample of six Local Group dwarf irregular galaxies. We des

L. Mosoni, S. Frey, L. I. Gurvits, M. A. Garrett

We present the results of the pilot observations of the Deep Extragalactic VLBI-Optical Survey (DEVOS). Our ultimate aim is to collect information on compact structures in a large sample of extragalactic radio sources (~10000 objects) up to two orders of magnitude fainter than those studied in typical imaging Very Long Baseline Interferometry (VLBI) surveys

Dominic J. Benford, Michael J. Amato, John C. Mather, S. Harvey Moseley

The Single Aperture Far-InfraRed (SAFIR) Observatory&#39;s science goals are driven by the fact that the earliest stages of almost all phenomena in the universe are shrouded in absorption by and emission from cool dust and gas that emits strongly in the far-infrared and submillimeter. Over the past several years, there has been an increasing recognition of t

T. H. Dall, H. Bruntt, K. G. Strassmeier, .

We present the first in a series of papers that attempt to investigate the relation between binarity, magnetic activity, and chemical surface abundances of cool stars. In the current paper, we lay out and test two abundance analysis methods and apply them to two well-known, active, single stars, HD 27536 (G8IV-III) and HD 216803 (K5V), presenting photospheri

Ekaterina Koptelova, Elena Shimanovskaya

The analysis of the high magnification events in the A and C components of the quadruple gravitational lens QSO2237+0305 observed by OGLE and GLITP collaborations in V band was carried out. The significant light amplifications of the components are interpreted as the effect of microlensing with a fold caustic. For the reconstruction of the one-dimensional so

A. E. Piskunov, N. V. Kharchenko, S. Röser, E. Schilbach

We present results of a study of the galactic open cluster population based on the all-sky catalogue ASCC-2.5 (I/280A) compiled from Tycho-2, Hipparcos and other catalogues. The sample of optical clusters from ASCC-2.5 is complete up to about 850 pc from the Sun. The symmetry plane of the clusters&#39; distribution is determined to be at $Z_0=-22\pm4$ pc, an

Bo Qin, Ue-Li Pen, Joseph Silk

Recent astronomical observations of systems of dark matter, which have been cited as providing possible support for self-interacting cold dark matter, may provide evidence for the extra dimensions predicted by superstring scenarios. We find that the properties of the required dark matter self-interaction are precisely the consequences of a world with 3 large

L. Magnani, S. Lugo, T. M. Dame

Spectra in the CH $^2Π_{1/2}$, J=1/2, F=1-1 transition at 3335 MHz were obtained in three 5-point crosses centered on the Galactic plane at $\ell =$ 50$\arcdeg$, 100$\arcdeg$, and 110$\arcdeg$. The lines of sight traverse both Giant Molecular Clouds (GMCs) and local, smaller entities. This transition is a good tracer of low-density molecular gas and the line

W. Bian, Q. Yuan, Y. Zhao

We investigate the radial velocity difference between the narrow emission-line components of [O III] $λ$ 5007 and H$β$ in a sample of 150 SDSS NLS1s. Seven &#34;blue outliers&#34; with [O III] blueshifted by more than 250 \kms are found. A strong correlation between the [O III] blueshift and the Eddington ratio is found for these seven &#34;blue outliers&#34

Y. Uchiyama, C. M. Urry, J. Van Duyne, C. C. Cheung

Emission from the relativistic jet located at hundreds of kpc from the core of the superluminal quasar PKS 0637-752 was detected at 3.6 and 5.8 microns with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. The unprecedented sensitivity and arcsecond resolution of IRAC allows us to explore the mid-infrared emission from kiloparsec-scale quasar

Vahe Petrosian, Huirong Yan, Alex Lazarian

(Abridged) We describe the cascade of plasma waves or turbulence injected, presumably by reconnection, at scales comparable to the size of a solar flare loop to scales comparable to particle gyroradii, and evaluate their damping by various mechanisms. We show that the classical viscous damping is unimportant for magnetically dominated or low beta plasmas and

Helmut Jerjen

The Surface Brightness Fluctuation method has been shown to be a powerful distance indicator for dwarf elliptical galaxies to very low surface brightness levels. It is applicable to stellar systems that are out of reach for classical indicators requiring resolved stellar populations such as the tip magnitude of the red giant branch. I briefly discuss a few r

David A. Tilley, Ralph E. Pudritz

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an exhaustive analysis of numerical data from these simulations that includes a compilation of all of the distributions of phy

Christos G. Tsagas

Inflation is known to produce both gravitational waves and seed magnetic fields on scales well beyond the size of the horizon. The general relativistic interaction between these two sources at the end of inflation showed a significant amplification of the initial magnetic seed, which brought the latter within the currently accepted dynamo limits. In the pres

Dmitry Kleinbock

We present a sharpening of nondivergence estimates for unipotent (or more generally polynomial-like) flows on homogeneous spaces. Applied to metric Diophantine approximation, it yields precise formulas for Diophantine exponents of affine subspaces of $\Bbb R^n$ and their nondegenerate submanifolds.

Ignacio Garcia-Mata, Marcos Saraceno, Maria Elena Spina, Gabriel Carlo

We give a criterion to differentiate between dissipative and diffusive quantum operations. It is based on the classical idea that dissipative processes contract volumes in phase space. We define a quantity that can be regarded as ``quantum phase space contraction rate&#39;&#39; and which is related to a fundamental property of quantum channels: non-unitality

Anne M. Green, Stefan Hofmann, Dominik J. Schwarz

The dark matter distribution on small scales may depend on the the properties of the first generation of dark matter halos to form, which is in turn determined by the microphysics of the dark matter particles. We overview the microphysics of WIMPs and our calculations of the collisional damping and free streaming scales. We then plot the resulting density pe

Candis Holtz, Kenneth Price

Let R be a Noetherian domain and let (σ, δ) be a quasi-derivation of R such that σ is an automorphism. There is an induced quasi-derivation on the classical quotient ring Q of R. Suppose F = t^2 - v is normal in the Ore extension R[t; σ, δ] where v ε R. We show F is prime in R[t; σ, δ] if and only if F is irreducible in Q[t; σ, δ] if and only if there does n

Cedric Lecouvey, Mark Shimozono

In this paper we complete the proof of the X=K conjecture, that for every family of nonexceptional affine algebras, the graded multiplicities of tensor products of symmetric power Kirillov-Reshetikhin modules known as one-dimensional sums, have a large rank stable limit X that has a simple expression (called the K-polynomial) as nonnegative integer combinati

Joel Koplik, Jayanth R. Banavar

The conventional boundary conditions at the interface between two flowing liquids include continuity of the tangential velocity. We have tested this assumption with molecular dynamics simulations of Couette and Poiseuille flows of two-layered liquid systems, with various molecular structures and interactions. When the total liquid density near the interface

Takuya Okuda, Yutaka Ookouchi

We study large classes of renormalization group flows, driven by scalar expectation values or mesonic superpotential terms, away from the conformal fixed points of the 4d supersymmetric gauge theories with $ADE$-type superpotentials. The $a$-maximization procedure allows us to compute the $R$ charges and to check the $a$-theorem conjecture. For a theory obta

D. Mukamel, S. Ruffo, N. Schreiber

The thermodynamic and dynamical properties of an Ising model with both short range and long range, mean field like, interactions are studied within the microcanonical ensemble. It is found that the relaxation time of thermodynamically unstable states diverges logarithmically with system size. This is in contrast with the case of short range interactions wher

C. Goldmann, D. J. Gundlach, B. Batlogg

We report on the generation of a discrete trap state during negative gate bias stress in pentacene single crystal &#34;flip-crystal&#34; field-effect transistors with a SiO2 gate dielectric. Trap densities of up to 2*10^12 cm^-2 were created in the experiments. Trap formation and trap relaxation are distinctly different above and below ~280 K. In devices in

Xiangyong Zeng, Lei Hu, Qingchong Liu

A family of binary sequences is presented and proved to have optimal correlation property and large linear span. It includes the small set of Kasami sequences, No sequence set and TN sequence set as special cases. An explicit lower bound expression on the linear span of sequences in the family is given. With suitable choices of parameters, it is proved that

S. Moch, A. Vogt

Utilizing recent three-loop results on the quark and gluon splitting functions and form factors, we derive the complete threshold-enhanced third-order (N^3LO) QCD corrections to the total cross sections for the production of lepton pairs and the Higgs boson in hadron collisions. These results, for the latter case obtained in the heavy top-quark limit, are em

D. Blaschke, Yu. L. Kalinovsky, A. E. Radzhabov, M. K. Volkov

Properties and temperature behavior of pi and sigma bound states are studied in the framework of the nonlocal model with a separable interaction kernel based on the quark Dyson-Schwinger and the meson Bethe-Salpeter equations. M_pi(T), f_pi(T), M_sigma(T) and Gamma_{sigma -> pi pi}(T) are considered above and below the deconfinement and chiral restoration tr

Kang Li, Sayipjamal Dulat

The Aharonov-Bohm (AB) effect in non-commutative quantum mechanics (NCQM) is studied. First, by introducing a shift for the magnetic vector potential we give the Schr$\ddot{o}$dinger equations in the presence of a magnetic field on NC space and NC phase space, respectively. Then by solving the Schr$\ddot{o}$dinger equations, we obtain the Aharonov-Bohm (AB)

Massimo Giovannini

Possible effects of large-scale magnetic fields on the Cosmic Microwave Background (CMB) are reviewed. Depending on the specific branch of the spectrum of plasma excitations, magnetic fields are treated either within a two-fluid plasma description or within an effective (one-fluid) approach. The uniform field approximation is contrasted with the fully inhomo

Shmuel Friedland, Christian Krattenthaler

We prove the conjecture of Falikman--Friedland--Loewy on the parity of the degrees of projective varieties of $n\times n$ complex symmetric matrices of rank at most $k$. We also characterize the parity of the degrees of projective varieties of $n\times n$ complex skew symmetric matrices of rank at most $2p$. We give recursive relations which determine the pa

Bin Chen

In this paper, we study the half-supersymmetric time-dependent configurations in M-theory and their matrix models. We find a large class of 11D supergravity solutions, which keeps sixteen supersymmetries. Furthermore, we investigate the isometries of these configurations and show that in general these configurations have no supernumerary supersymmetries. And

Rodolphe Hoppeler, Jose Viana Gomes, Denis Boiron

We have studied the atomic density of a cloud confined in an isotropic harmonic trap at the vicinity of the Bose-Einstein transition temperature. We show that, for a non-interacting gas and near this temperature, the ground-state density has the same order of magnitude as the excited states density at the centre of the trap. This holds in a range of temperat

W. Wonneberger

The problem of the Kohn mode in bosonized theories of one-dimensional interacting fermions in the harmonic trap is investigated and a suitable modification of the interaction is proposed which preserves the Kohn mode. The modified theory is used to calculate exactly the inhomogeneous linear mobility at position z in response to a spatial force pulse at anoth

Shinji Tsujikawa

The reconstruction of scalar-field dark energy models is studied for a general Lagrangian density $p(ϕ, X)$, where $X$ is a kinematic term of a scalar field $ϕ$. We implement the coupling $Q$ between dark energy and dark matter and express reconstruction equations using two observables: the Hubble parameter $H$ and the matter density perturbation $δ_m$. This

J. Gorosabel, D. Perez-Ramirez, J. Sollerman, A. de Ugarte Postigo

In this study optical/near-infrared(NIR) broad band photometry and optical spectroscopic observations of the GRB 030329 host galaxy are presented. The Spectral Energy Distribution (SED) of the host is consistent with a starburst galaxy template with a dominant stellar population age of ~150 Myr and an extinction Av ~0.6. Analysis of the spectral emission lin

Jounghun Lee

We analyze the C4 catalog of galaxy clusters from the Sloan Digital Sky Survey (SDSS) to investigate the axis-ratio distribution of the projected two dimensional cluster profiles. We consider only those objects in the catalog whose virial mass is close to 10^{14}h^{-1}M_{sun}, with member galaxies within the scale radius 1000 kpc. The total number of such ob

Bhuwan Joshi, P. Pant, P. K. Manoharan

In this paper, we investigate the spatial distribution of solar flares in the northern and southern hemisphere of the Sun that occurred during the period 1996 to 2003. This period of investigation includes the ascending phase, the maximum and part of descending phase of solar cycle 23. It is revealed that the flare activity during this cycle is low compared

Alexander Borisov, Evgeny I. Buchbinder, Burt A. Ovrut

The small instanton transition of a five-brane colliding with one end of the S1/Z2 interval in heterotic M-theory is discussed, with emphasis on the transition moduli, their potential function and the associated non-perturbative superpotential. Using numerical methods, the equations of motion of these moduli coupled to an expanding Friedmann-Robertson-Walker

V. V. Varlamov

A group structure of the discrete transformations (parity, time reversal and charge conjugation) for spinor field in de Sitter space are studied in terms of extraspecial finite groups. Two $CPT$ groups are introduced, the first group from an analysis of the de Sitter-Dirac wave equation for spinor field, and the second group from a purely algebraic approach

Leon A. Takhtajan, Lee-Peng Teo

Using Polyakov&#39;s functional integral approach with the Liouville action functional defined in \cite{ZT2} and \cite{LTT}, we formulate quantum Liouville theory on a compact Riemann surface X of genus g > 1. For the partition function <X> and for the correlation functions with the stress-energy tensor components $<\prod_{i=1}^{n}T(z_{i})\prod_{k=1}^{l}\bar

C. E. Aguiar, F. A. Barone

We study the effect of radiation damping on the classical scattering of charged particles. Using a perturbation method based on the Runge-Lenz vector, we calculate radiative corrections to the Rutherford cross section, and the corresponding energy and angular momentum losses.

Chuan Liu, Xu Feng, Song He

Using a quantum mechanical model, the exact energy eigenstates for two-particle two-channel scattering are studied in a cubic box with periodic boundary conditions. A relation between the exact energy eigenvalue in the box and the two-channel $S$-matrix elements in the continuum is obtained. This result can be viewed as a generalization of the well-known Lüs

M. Revzen, F. C. Khanna, A. Mann, J. Zak

A Hilbert space in M dimensions is shown explicitly to accommodate representations that reflect the prime numbers decomposition of M. Representations that exhibit the factorization of M into two relatively prime numbers: the kq representation (J. Zak, Phys. Today, {\bf 23} (2), 51 (1970)), and related representations termed $q_{1}q_{2}$ representations (toge

Stefan Scheel

We derive a lower limit to the amount of absorptive loss present in passive linear optical devices such as a beam splitter. We choose a particularly simple beam splitter geometry, a single planar slab surrounded by vacuum, which already reveals the important features of the theory. It is shown that, using general causality requirements and statistical argume

E. K. Bashkirov

The entanglement between two identical two-level atoms interacting with two mode thermal field through a nondegenerate two-photon process has been suggested. It has been shown that for some atomic initial state the entanglement induced by nondegenerate two-photon interaction is larger than that induced by one-photon and degenerate two-photon processes.