April 2006 arXiv papers — page 18

Yongho Seo, Paul Cadden-Zimansky, Venkat Chandrasekhar

We have developed a low-temperature scanning probe microscope using a quartz tuning fork operating at 4.2 K. A silicon tip from a commercial cantilever was attached to one prong of the tuning fork. With a metallic coating, a potential could be applied to the tip to sense the charge distribution in a sample, while with a magnetically coated tip, magnetic forc

Ming-Hao Liu, Ching-Ray Chang

We present a theoretical method to calculate the expectation value of spin in an inversion-asymmetric two-dimensional (2D) system with respect to an arbitrarily spin-polarized electron state, injected via an ideal point contact. The 2D system is confined in a [001]-grown quantum well, where both the Rashba and the Dresselhaus spin-orbit couplings are taken i

A. Langari, S. Mahdavifar

We have calculated numerically the gap exponent of the anisotropic Heisenberg model in the presence of the transverse magnetic field. We have implemented the modified Lanczos method to obtain the excited states of our model with the same accuracy of the ground state. The coefficient of the leading term in the perturbation expansion diverges in the thermodyna

R. Yamamoto, K. Kim, Y. Nakayama, K. Miyazaki

In this letter, we investigate several aspects related to the effect of hydrodynamics interactions on phase separation-induced gelation of colloidal particles. We explain physically the observation of Tanaka and Araki[Phys. Rev. Lett. {\bf 85}, 1338 (2000)] of hydrodynamic stabilization of cellular network structures in two dimensions. We demonstrate that hy

E. O. Kamenetskii

Bianisotropics is conceived as a physical concept describing electromagnetic media which possess intrinsic mechanisms of magnetoelectric coupling. We propose the main idea of bianisotropics as a combination of two physical notions: (a) the near-field manipulation and (b) chirality. From classical laws these two notions are in an evident contradiction since m

Ming-Hao Liu, Ching-Ray Chang

We analyze the spin expectation values for injected spin-polarized electrons (spin vectors) in a [001]-grown Rashba-Dresselhaus two-dimensional electron gas (2DEG). We generalize the calculation for point spin injection in semi-infinite 2DEGs to finite-size spin injection in bounded 2DEGs. Using the obtained spin vector formula, significance of the channel d

Ming-Hao Liu, Son-Hsien Chen, Ching-Ray Chang

We demonstrate that in an inversion-asymmetric two-dimensional electron system 2DES with both Rashba and Dresselhaus spin-orbit couplings taken into account, certain transport directions on which no spin precession occurs can be found when the injected spin is properly polarized. By analyzing the expectation value of spin with respect to the injected electro

Yunori Nisikawa, Manabu Usuda, Jun-ichi Igarashi

We investigate theoretically the resonant inelastic x-ray scattering (RIXS) at the $K$ edge of Si on the basis of an ab initio calculation. We calculate the RIXS spectra with systematically varying transfered-momenta, incident-photon energy and incident-photon polarization. We confirm the anisotropy of the experimental spectra by Y. Ma {\it et al}. (Phys. Re

Yunori Nisikawa, Hiroaki Ikeda, Kosaku Yamada

To discuss a possibility that the superconductivities in Na_xCoO_2yH_2O are induced by the electron correlation, we investigate the possible pairing symmetry based on the single-band Hubbard model whose dispersion of the bare energy band is obtained by using FLAPW-LDA band structure calculation of Na_xCoO_2yH_2O. The superconducting transition temperature is

Yunori Nisikawa, Manabu Usuda, Jun-ichi Igarashi, Hironobu Shoji

We study the resonant inelastic x-ray scattering (RIXS) at the $K$ edge of Ge. We measure RIXS spectra with systematically varying momenta in the final state. The spectra are a measure of exciting an electron-hole pair. We find a single peak structure (except the elastic peak) as a function of photon energy, which is nearly independent of final-state momenta

Shinya Sugiyama, Edison Liang, Koichi Noguchi, Hideaki Takabe

We report the Compton scattering emission from the Poynting flux acceleration of electron- positron plasma simulated by the 2-1/2 dimensional particle-in-cell(PIC) code. We show these and other remarkable properties of Poynting flux acceleration and Compton spectral output, and discuss the agreement with the observed spectra of GRBs and XRFs.

E. Unda-Sanzana, T. R. Marsh, L. Morales-Rueda

U Gem is unique in having a direct measurement of K1 = 107 +- 2 km/s, Long et al. 1999). We present high-resolution optical spectra of the dwarf nova U Gem in quiescence taken to test the accuracy to which the HST value can be recovered from optical data. We find that, even with data of very high S/N we cannot recover Long et al.'s value to better than a

Valentin Kostov

We model a spiral galaxy by a thin axially symmetric disk that includes both visible and dark matter. The surface mass density of the disk is calculated directly from the rotational velocity curve without extra assumptions. We simplify the standard application of the model. Since most velocity curves are known out to some radius, r_{max}, we extrapolate them

David H. Weinberg, Stephane Colombi, Romeel Davé, Neal Katz

By comparing a collisionless cosmological N-body simulation (DM) to an SPH simulation with the same initial conditions, we investigate the correspondence between the dark matter subhalos produced by collisionless dynamics and the galaxies produced by dissipative gas dynamics in a dark matter background. When galaxies in the SPH simulation become satellites i

Dawn K. Erb, Charles C. Steidel, Alice E. Shapley, Max Pettini

Using H-alpha spectra of 114 rest-frame UV-selected galaxies at z~2, we compare inferred star formation rates (SFRs) with those determined from the UV continuum luminosity. After correcting for extinction using standard techniques based on the UV continuum slope, we find excellent agreement between the indicators, with <SFR_Ha> = 31 Msun/yr and <SFR_UV> = 29

Nanda Rea

We first review on the peculiar characteristics of the bursting and flaring activity of the Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars. We then report on the properties of the SGR 1806-20&#39;s Giant Flare occurred on 2004 December 27th, with particular interest on the pre and post flare intensity/hardness correlated variability. We show that these

A. Recio-Blanco, A. Bijaoui, P. de Laverny

We present an automated procedure for the derivation of atmospheric parameters (Teff, log g, [M/H]) and individual chemical abundances from stellar spectra. The MATrix Inversion for Spectral SythEsis (MATISSE) algorithm determines a basis, B_θ(λ), allowing to derive a particular stellar parameter θby projection of an observed spectrum. The B_θ(λ) function is

Nathan Roche, James Dunlop, Karina Caputi, Ross McLure

We have performed a deep spectroscopic survey of extremely red galaxies on the GOODS-South field, using GMOS on Gemini South. We present here spectra and redshifts for 16 ERGs at 0.87<z<2.02, to a limit K=20.2. The ERHs are a mixture of spheroidals, mergers and spirals, with one AGN. For at least 10 of these galaxies we observe [OII] emission lines. We perfo

Itahiza Dominguez Cerdena, Jorge Sanchez Almeida, Franz Kneer

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of the observed Stokes profiles under the MISMA hypothesis. The observations cover an intra-network region at the solar dis

F. X. Alvarez

A thermodynamic model for the generation of magnetic fields in the planets is proposed, considering crossed effects between gravitational and electric forces. The magnetic field of the Earth is estimated and found to be in agreement with the actual field. The ratio between the field of several planets and that of the Earth is calculated in the model and comp

G. Lamer, A. Schwope, L. Wisotzki, L. Christensen

We present simultaneous XMM-Newton UV and X-ray observations of the quadruply lensed quasar SDSS J1004+4112 (RBS 825). Simultaneously with the XMM-Newton observations we also performed integral field spectroscopy on the two closest lens images A and B using the Calar Alto PMAS spectrograph. In X-rays the widely spaced components C and D are clearly resolved,

I. Perez, K. Freeman

In this paper we test the idea that the low-metallicity hot gas in the centre of NGC 1291 is heated via a dynamical process. In this scenario, the gas from the outer gas-rich ring loses energy through bar-driven shocks and falls to the centre. Heating of the gas to X-ray temperatures comes from the high velocity that it reaches ($\approx$ 700 \kms) as it fal

G. Ruediger, L. L. Kitchatinov

A plane-shear flow in a fluid with forced turbulence is considered. If the fluid is electrically-conducting then a mean electromotive force (EMF) results even without basic rotation and the magnetic diffusivity becomes a highly anisotropic tensor. It is checked whether in this case self-excitation of a large-scale magnetic field is possible (so-called WxJ-dy

B. Siana, M. Polletta, H. E. Smith, C. J. Lonsdale

We use a simple optical/infrared photometric selection of high redshift QSOs which identifies a Lyman Break in the optical and requires a red IRAC color to distinguish QSOs from common interlopers. We find 100 U-dropout (z=3) QSO candidates with r&#39;<22 within 11.2 deg^2 in the ELAIS-N1 & ELAIS-N2 fields in the Spitzer Wide-Area Infrared Extragalactic (SWI

J. Puls, N. Markova, S. Scuderi, C. Stanghellini

Recent results strongly challenge the canonical picture of massive star winds: various evidence indicates that currently accepted mass-loss rates, Mdot, may need to be revised downwards significantly. This is because the most commonly used mass-loss diagnostics are affected by ``clumping&#39;&#39; (small-scale density inhomogeneities), influencing our interp

Wei-Min Gu, Tong Liu, Ju-Fu Lu

We first refine the fixed concept in the literature that the usage of the Newtonian potential in studies of black hole accretion is invalid and the general relativistic effect must be considered. As our main results, we then show that the energy released by neutrino annihilation in neutrino-dominated accretion flows is sufficient for gamma-ray bursts when th

J. D. Bregman, J. N. Bregman, P. Temi

In a sample of thirty normal elliptical galaxies observed with the Spitzer IRS, one galaxy, NGC4697, shows strong PAH emission, but with an apparently weak 7.7 micron feature. We find that the PAH emission is confined to the central regions of the galaxy and that once a quiescent elliptical galaxy spectrum is subtracted, the PAH feature ratios are normal. We

N. Vranesevic, D. B. Melrose, R. N. Manchester

The Parkes Multibeam Survey led to the identification ofa number of long-period radio pulsars with magnetic field well above the quantum critical field of 4.4 times 10 to 13 G (defined as high magnetic field radio pulsars - HBRPs). Traditional pulsar emission theories postulate that radio emission is suppressed above this critical field. The aim of thisproje

Havard Alnes, Morad Amarzguioui, Oyvind Gron

Recently, there have been suggestions that the apparent accelerated expansion of the universe is not caused by repulsive gravitation due to dark energy, but is rather a result of inhomogeneities in the distribution of matter. In this work, we investigate the behaviour of a dust dominated inhomogeneous Lemaitre-Tolman-Bondi universe model, and confront it wit

Soebur Razzaque, Peter Meszaros, Eli Waxman

The ratio of anti-electron to total neutrino flux, $Φ_{\barν_e}:Φ_ν$, expected from $pγ$ interactions in astrophysical sources is $\le1:15$. We point out that this ratio is enhanced by the decay of $μ^+μ^-$ pairs, created by the annihilation of secondary high energy photons from the decay of the neutral pions produced in $pγ$ interactions. We show that, unde

Olga Holtz, Bernd Sturmfels

The principal minors of a symmetric $n{\times}n$-matrix form a vector of length $2^n$. We characterize these vectors in terms of algebraic equations derived from the $ 2{\times}2{\times}2$-hyperdeterminant.

Xin-Nian Wang

Similar to the radiative parton energy loss due to gluon bremsstrahlung, elastic energy loss of a parton undergoing multiple scattering in a finite medium is demonstrated to be sensitive to interference effect. The interference between amplitudes of elastic scattering via a gluon exchange and that of gluon radiation reduces the effective elastic energy loss

P. Bryans, N. R. Badnell, T. W. Gorczyca, J. M. Laming

Reliably interpreting spectra from electron-ionized cosmic plasmas requires accurate ionization balance calculations for the plasma in question. However, much of the atomic data needed for these calculations have not been generated using modern theoretical methods and are often highly suspect. This translates directly into the reliability of the collisional

D. Reyna

The designs of many neutrino experiments rely on calculations of the background rates arising from cosmic-ray muons at shallow depths. Understanding the angular dependence of low momentum cosmic-ray muons at the surface is necessary for these calculations. Heuristically, from examination of the data, a simple parameterization is proposed, based on a straighf

M. E. Gabach Clement, G. A. Raggio

For two qubits and for general bipartite quantum systems, we give a simple spectral condition in terms of the ordered eigenvalues of the density matrix which guarantees that the corresponding state is separable.

Martin Schaden

The electromagnetic Casimir energies of a spherical and a cylindrical cavity are analyzed semiclassically. The field theoretical self-stress of a spherical cavity with ideal metallic boundary conditions is reproduced to better than 1%. The subtractions in this case are unambiguous and the good agreement is interpreted as evidence that finite contributions fr

Stephen L. Adler

This is a revision of my original posting, in which I raised objections to part of the Conway-Kochen argument. I now agree with them that their recent reply answers my original concerns. In the first part of these notes (identical to the original), I give a reformulation of the part of the Conway-Kochen result that closes the contextuality loophole in the or

K. Zumbrun

Recently, Benzoni--Gavage, Danchin, Descombes, and Jamet have given a sufficient condition for linear and nonlinear stability of solitary wave solutions of Korteweg&#39;s model for phase-transitional isentropic gas dynamics in terms of convexity of a certain ``moment of instability&#39;&#39; with respect to wave speed, which is equivalent to variational stab

Ramin G. Daghigh, Gabor Kunstatter, Dave Ostapchuk, Vince Bagnulo

We analyze in detail the highly damped quasinormal modes of $d$-dimensional Reissner-Nordstr$\ddot{\rm{o}}$m black holes with small charge, paying particular attention to the large but finite damping limit in which the Schwarzschild results should be valid. In the infinite damping limit, we confirm using different methods the results obtained previously in t

K. Bering

We revisit Khudaverdian&#39;s geometric construction of an odd nilpotent operator Δ_E that sends semidensities to semidensities on an antisymplectic manifold. We find a local formula for the Δ_E operator in arbitrary coordinates and we discuss its connection to Batalin-Vilkovisky quantization.

Stephen Clark

We know from previous work \cite{clark} that non topological solitons, Q balls, evaporate into fermions. All the constructions we used to find evaporation rate were dased on the fact that no fermions would move towards the Q ball. All these constructions left an opened question that is : what happens when a fermion interacts with a Q ball. We shall answer th

R. D. Young, J. Roche, R. D. Carlini, A. W. Thomas

The complete world set of parity violating electron scattering data up to Q^2~0.3 GeV^2 is analysed. We extract the current experimental determination of the strange electric and magnetic form factors of the proton, as well as the weak axial form factors of the proton and neutron, at Q^2 = 0.1 GeV^2. Within experimental uncertainties, we find that the strang

The BABAR Collaboration, B. Aubert

We present measurements of the branching fractions and charge asymmetries of B decays to all D(*)D(*) modes. Using 232 million BBbar pairs recorded on the Upsilon(4S) resonance by the BaBar detector at the e+e- asymmetric B factory PEP-II at the Stanford Linear Accelerator Center, we measure the branching fractions BF(B0 -> D*+D*-) = (8.1 +- 0.6 +- 1.0) x 10

Iosif Bena, Chih-Wei Wang, Nicholas P. Warner

We find a very large set of smooth horizonless geometries that have the same charges and angular momenta as the five-dimensional, maximally-spinning, three-charge, BPS black hole (J^2 = Q^3). Our solutions are constructed using a four-dimensional Gibbons-Hawking base space that has a very large number of two-cycles. The entropy of our solutions is proportion

Matthew Daws

We study representations of Banach algebras on reflexive Banach spaces. Algebras which admit such representations which are bounded below seem to be a good generalisation of Arens regular Banach algebras; this class includes dual Banach algebras as defined by Runde, but also all group algebras, and all discrete (weakly cancellative) semigroup algebras. Such

C. Monteserin, R. B. Barreiro, E. Martinez-Gonzalez, J. L. Sanz

We study the power of several scalar quantities constructed on the sphere (presented in Monteserin et al. 2005) to detect non-Gaussianity on the temperature distribution of the cosmic microwave background (CMB). The test has been performed using non-Gaussian CMB simulations with injected skewness or kurtosis generated through the Edgeworth expansion. We have

Andrey Loginov

The Run I results on the searches for new physics in photon final states were intriguing. The rare 2 electrons + 2 photons + missing transverse energy (MET) candidate event and the measured event rate for the signature lepton + photon + MET, which was 2.7 sigma above the Standard Model predictions, sparked signature-based searches in the photon + photon + X

V. Belokurov, D. B. Zucker, N. W. Evans, M. I. Wilkinson

In this Letter, we announce the discovery of a new satellite of the Milky Way in the constellation of Bootes at a distance of 60 kpc. It was found in a systematic search for stellar overdensities in the North Galactic Cap using Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude diagram shows a well-defined turn-off, red giant branch, and

Pascal Baseilhac

The spectral properties of operators formed from generators of the q-Onsager non-Abelian infinite dimensional algebra are investigated. Using a suitable functional representation, all eigenfunctions are shown to obey a second-order q-difference equation (or its degenerate discrete version). In the algebraic sector associated with polynomial eigenfunctions (o

Kurusch Ebrahimi-Fard, Li Guo

Recently, the theory of renormalization in perturbative quantum field theory underwent some exciting new developments. Kreimer discovered an organization of Feynman graphs into combinatorial Hopf algebras. The process of renormalization is captured by a factorization theorem for regularized Hopf algebra characters. In this context the notion of Rota-Baxter a

Pascal Baseilhac

A family of tridiagonal pairs which appear in the context of quantum integrable systems is studied in details. The corresponding eigenvalue sequences, eigenspaces and the block tridiagonal structure of their matrix realizations with respect the dual eigenbasis are described. The overlap functions between the two dual basis are shown to satisfy a coupled syst

R. Bijker

In this contribution, I discuss the role of symmetries and algebraic methods in nuclear structure physics. In particular, I review some recent developments in nuclear supersymmetry and indicate possible applications for light nuclei in the sd- and pf-shell.

M. S. Shahriar, G. S. Pati, K. Salit

Recently, we have shown that for conditions under which the so-called light-shift imbalance induced blockade (LSIIB) occurs, the collective excitation of an ensemble of a multi-level atom can be treated as a closed two level system. In this paper, we describe how such a system can be used as a quantum bit (qubit) for quantum communication and quantum computi

M. S. Shahriar, P. Pradhan, G. S. Pati, V. Gopal

Current proposals focusing on neutral atoms for quantum computing are mostly based on using single atoms as quantum bits (qubits), while using cavity induced coupling or dipole-dipole interaction for two-qubit operations. An alternative approach is to use atomic ensembles as qubits. However, when an atomic ensemble is excited, by a laser beam matched to a tw

Claudia de Rham, Tetsuya Shiromizu, Andrew J. Tolley

Braneworld models typically predict gravity to grow stronger at short distances. In this paper, we consider braneworlds with two types of additional curvature couplings, a Gauss-Bonnet term in the bulk, and an Einstein-Hilbert (EH) term on the brane. In the regime where these terms are dominant over the bulk EH term, linearized gravity becomes weaker at shor

Liming Wang, Eduardo D. Sontag

This paper deals with global convergence to equilibria, and in particular Hirsch&#39;s generic convergence theorem for strongly monotone systems, for singular perturbations of monotone systems.

A. Markowitz, J. Reeves, V. Braito

We present a detailed analysis of the XMM-Newton long-look of the Seyfert galaxy IC 4329a. The Fe K bandpass is dominated by two resolved peaks at 6.4 keV and 7.0 keV, consistent with neutral or near-neutral Fe K alpha and K beta emission. There is a prominent redward asymmetry in the 6.4 keV line, which could indicate emission from a Compton shoulder. Alter

Osvaldo Chandia

The classical pure spinor version of the heterotic superstring in a supergravity and super Yang-Mills background is considered. We obtain the BRST transformations of the world-sheet fields. They are consistent with the constraints obtained from the nilpotence of the BSRT charge and the holomorphicity of the BRST current.

P. M. Ferreira, R. Santos

We study the effects of a set of dimension six flavor changing effective operators on several processes of production of top quarks at the LHC. Namely, top anti-top production and associated production of a top and a gauge or Higgs boson. Analytical expressions for the cross sections of these processes are derived and presented.

R. Trampedach, W. Dappen, V. A. Baturin

A detailed comparison is carried out between two popular equations of state (EOS), the Mihalas-Hummer-Dappen (MHD) and the OPAL equations of state, which have found widespread use in solar and stellar modeling during the past two decades. They are parts of two independent efforts to recalculate stellar opacities; the international Opacity Project (OP) and th

John D. Barrow, T. Clifton

We provide a simple mathematical description of the exchange of energy between two fluids in an expanding Friedmann universe with zero spatial curvature. The evolution can be reduced to a single non-linear differential equation which we solve in physically relevant cases and provide an analysis of all the possible evolutions. Particular power-law solutions e

C. Quesne, V. M. Tkachuk

The $D$-dimensional $(β, β&#39;)$-two-parameter deformed algebra introduced by Kempf is generalized to a Lorentz-covariant algebra describing a ($D+1$)-dimensional quantized space-time. In the D=3 and $β=0$ case, the latter reproduces Snyder algebra. The deformed Poincaré transformations leaving the algebra invariant are identified. It is shown that there ex

Zhibin Zhang, G. Z. Xie, J. G. Deng, W. Jin

In this paper, we restudy the spectral lag features of short bright gamma-ray bursts (T90 < 2.6s) with a BATSE time-tagged event (TTE) sample including 65 single pulse bursts. We also make an investigation on the characteristics of ratios between the spectral lag and the full width at half maximum ($FWHM$) of the pulses, called relative spectral lags (RSLs).

E. Gabrielli, K. Huitu, S. Roy

We consider the minimal coupling of two photons to neutral scalar and pseudoscalar fields, as for instance in the case of the Higgs boson and axion, respectively. In this framework, we analyze the photon dispersion relations in the presence of static and homogeneous external magnetic and electric fields, by taking into account the contribution of the imagina

Shankar Bhamidi, Ram Rajagopal, Sebastien Roch

We demonstrate the use of computational phylogenetic techniques to solve a central problem in inferential network monitoring. More precisely, we design a novel algorithm for multicast-based delay inference, i.e. the problem of reconstructing the topology and delay characteristics of a network from end-to-end delay measurements on network paths. Our inference

Masataka Fukugita, Takahiro Kubota

In a recent letter Marciano and Sirlin (Phys. Rev. Lett. 96, 032002, (2006)) presented an improved calculation of the electroweak radiative correction to derive a precision value of the quark mixing angle $V_{ud}$ by improving the continuation from long to short distance contributions. At the precision level considered by them, however, there is a more impor

Jiunn-Wei Chen, Eiji Nakano

Using chiral perturbation theory we investigate the QCD shear viscosity to entropy density ratio below the deconfinement temperature (~170 MeV) with zero baryon number density. It is found that the viscosity to entropy density ratio of QCD is monotonically decreasing in temperature (T) and reaches 0.6 with estimated ~50% uncertainty at T=120 MeV. A naive ext

A. Rostami, M. Boozarjmehr

The light propagation through one-dimensional photonic crystal using Four-wave mixing (FWM) nonlinear process is modeled. The linear and nonlinear indexes of refraction are approximated with the first Fourier harmonic term. Based on this approximation, a complete set of coupled wave equations, including pump fields depletion, for description of FWM process a

Fyodor V. Tkachov

The method of quasi-optimal weights provides a comprehensive, asymptotically optimal, transparent and flexible alternative to the least squares method. The optimality holds for a general non-linear, non-gaussian case.

Michael Dine, Ryuichiro Kitano, Alexander Morisse, Yuri Shirman

One proposed solution of the moduli problem of string cosmology requires that the moduli are quite heavy, their decays reheating the universe to temperatures above the scale of nucleosynthesis. In many of these scenarios, the moduli are approximately supersymmetric; it is then crucial that the decays to gravitinos are helicity suppressed. In this paper, we d

Ikumi Honda, Kiyosi Terao

We study the effects of magneto-elastic coupling on the degenerate ground spin-state of the antiferromagnetic Heisenberg model on a regular tetrahedron of spin-1/2. When displacement of spin is considered as a classical variable, the degeneracy is lifted through the distance dependence of exchange coupling, i.e., a kind of Jahn-Teller effect. On the other ha

Ravi Montenegro

This paper originally showed a lower bound on mixing time for a non-reversible Markov chain in terms of its largest non-trivial eigenvalue, and used this to re-derive some generalizations of results of Fan Chung. However, the paper has been withdrawn because I have been made aware that the lower bound was previously known.

John A. Johnson, Geoffrey W. Marcy, Debra A. Fischer, Gregory Laughlin

We present a modification to the iodine cell Doppler technique that eliminates the need for an observed stellar template spectrum. For a given target star, we iterate toward a synthetic template spectrum beginning with an existing spectrum of a similar star. We then perturb the shape of this first-guess template to match the program observation of the target

L. Raul Abramo, Armando Bernui, Ivan S. Ferreira, T. Villela

We investigate the large scale anomalies in the angular distribution of the cosmic microwave background radiation as measured by WMAP using several tests. These tests, based on the multipole vector expansion, measure correlations between the phases of the multipoles as expressed by the directions of the multipole vectors and their associated normal planes. W

Kazushi Ueda

We give a full exceptional collection in the triangulated category of singularities in the sense of Orlov for a hypersurface singularity of Fermat type, and discuss its relation with homological mirror symmetry for simple elliptic hypersurface singularities.

C. J. Gao, S. N. Zhang

The exact solutions of electrically charged phantom black holes with the cosmological constant are constructed. They are labelled by the mass, the electrical charge, the cosmological constant and the coupling constant between the phantom and the Maxwell field. It is found that the phantom has important consequences on the properties of black holes. In partic

Paolo Amore, Francisco M. Fernandez

We show that the asymptotic iteration method converges and yields accurate energies for a perturbed Coulomb model. We also discuss alternative perturbation approaches to that model.

Thomas Durt

We study different techniques that allow us to gain complete knowledge about an unknown quantum state, e.g. to perform full tomography of this state. We focus on two apparently simple cases, full tomography of one and two qubit systems. We analyze and compare those techniques according to two figures of merit. Our first criterion is the minimisation of the r

Kazuya Yuasa

We discuss the derivation of master equations in the presence of initial correlations with the reservoir. In van Hove&#39;s limit, the total system behaves as if it started from a factorized initial condition. A proper choice of Nakajima-Zwanzig&#39;s projection operator is crucial and the reservoir should be endowed with the mixing property.

Kazuyuki Fujii, Hiroshi Oike

How to calculate the exponential of matrices in an explicit manner is one of fundamental problems in almost all subjects in Science. Especially in Mathematical Physics or Quantum Optics many problems are reduced to this calculation by making use of some approximations whether they are appropriate or not. However, it is in general not easy. In this paper we g

Edelver Carnovali, Humberto M. Franca

We derive a classical Schrodinger type equation from the classical Liouville equation in phase space. The derivation is based on a Wigner type Fourier transform of the classical phase space probability distribution, which depends on an arbitrary constant $α$ with dimension of action. In order to achieve this goal two requirements are necessary: 1) It is assu

A. J. Faria, H. M. Franca, G. G. Gomes, R. C. Sponchiado

Several authors have used the Heisenberg picture to show that the atomic transitions, the stability of the ground state and the position-momentum commutation relation [x,p]=ih, can only be explained by introducing radiation reaction and vacuum electromagnetic fluctuation forces. Here we consider the simple case of a nonrelativistic charged harmonic oscillato

Gennady Margolin, Ivan V. Gregoretti, Holly V. Goodson, Mark S. Alber

A novel theoretical model of dynamic instability of a system of linear (1D) microtubules (MTs) in a bounded domain is introduced for studying the role of a cell edge in vivo and analyzing the effect of competition for a limited amount of tubulin. The model differs from earlier models in that the evolution of MTs is based on the rates of single unit (e.g., a

William W. Chen, Paul J. Choi, Jason E. Donald, Eugene I. Shakhnovich

To confer high specificity and affinity in binding, contacts at interfaces between two interacting macromolecules are expected to exhibit pair preferences for types of atoms or residues. Here we quantify these preferences by measuring the mutual information of contacts for 895 protein-protein interfaces. The information content is significant and is highest

A. K. Kuczaj, B. J. Geurts, W. D. McComb

Classically, large-scale forced turbulence is characterized by a transfer of energy from large to small scales via nonlinear interactions. We have investigated the changes in this energy transfer process in broad-band forced turbulence where an additional perturbation of flow at smaller scales is introduced. The modulation of the energy dynamics via the intr

Bin Liu, Jerome K. Percus

A fermion ground state energy functional is set up in terms of particle density, relative pair density, and kinetic energy tensor density. It satisfies a minimum principle if constrained by a complete set of compatibility conditions. A partial set, which thereby results in a lower bound energy under minimization, is obtained from the solution of model system

Bruno Denet

New stationary solutions of the (Michelson) Sivashinsky equation of premixed flames are obtained numerically in this paper. Some of these solutions, of the bicoalescent type recently described by Guidi and Marchetti, are stable with Neumann boundary conditions. With these boundary conditions, the time evolution of the Sivashinsky equation in the presence of

Lun-Shin Yao

There are many subtle issues associated with solving the Navier-Stokes equations. In this paper, several of these issues, which have been observed previously in research involving the Navier-Stokes equations, are studied within the framework of the one-dimensional Kuramoto-Sivashinsky (KS) equation, a model nonlinear partial-differential equation. This alter

Subharthi Ray, Manuel Malheiro, Jose&#39; P. S. Lemos, Vilson T. Zanchin

We review here the classical argument used to justify the electrical neutrality of stars and show that if the pressure and density of the matter and gravitational field inside the star are large, then a charge and a strong electric field can be present. For a neutron star with high pressure (~ 10^{33} to 10^{35} dynes /cm^2) and strong gravitational field (~

Anthony Kuhlman, Ulrich W. Heinz, Yuri V. Kovchegov

We examine entropy production in relativistic U+U collisions on the basis of a Color Glass Condensate (CGC) type picture as implemented in the Kharzeev-Levin-Nardi model (KLN). In this framework, we find that the peak entropy density produced in tip-on-tip U+U collisions is about 30% greater than that seen in central Au+Au collisions. Although the resulting

R. Alvarez-Rodriguez, P. Sarriguren, E. Moya de Guerra, L. Pacearescu

We study the effect of deformation on the two-neutrino double beta decay for ground state to ground state transitions in all the nuclei whose half-lives have been measured. Our theoretical framework is a deformed QRPA based in Woods-Saxon or Hartree-Fock mean fields. We are able to reproduce at the same time the main characteristics of the two single beta br

K. R. Esmakhanova, G. N. Nugmanova, Wei-Zhong Zhao, Ke Wu

The integrable inhomogeneous extension of the Lakshmanan-Myrzakulov equation is constructed by using the prolongation structure theory. The corresponding L-equivalent counterpart is also given, which is the (2+1)-dimensional generalized NLSE.

Sihong Shao, Huazhong Tang

This paper presents a further numerical study of the interaction dynamics for solitary waves in a nonlinear Dirac field with scalar self-interaction by using a fourth order accurate Runge-Kutta discontinuous Galerkin method. Our experiments are conducted on the Dirac solitary waves with a phase difference. Some interesting phenomena are observed: (a) full re

F. Demir, Z. T. Hlousek, Z. Papp

The two-body Coulomb Hamiltonian, when calculated in Coulomb-Sturmian basis, has an infinite symmetric tridiagonal form, also known as Jacobi matrix form. This Jacobi matrix structure involves a continued fraction representation for the inverse of the Green&#39;s matrix. The continued fraction can be transformed to a ratio of two $_{2}F_{1}$ hypergeometric f

Richard G. E. Pinch

We extend our previous computations to show that there are 1401644 Carmichael numbers up to $10^{18}$. As before, the numbers were generated by a back-tracking search for possible prime factorisations together with a ``large prime variation&#39;&#39;. We present further statistics on the distribution of Carmichael numbers.

Tobias J. Hagge

This addendum to math.LO/0412144 shows that the set of tautological quantum logical propositional formulas for a finite dimensional vector space C^n is different for every n, affirmatively answering a question posed therein.

Mark Braverman, Michael Yampolsky

We completely characterize the conformal radii of Siegel disks in the family $$P_θ(z)=e^{2πiθ}z+z^2,$$ corresponding to {\bf computable} parameters $θ$. As a consequence, we constructively produce quadratic polynomials with {\bf non-computable} Julia sets.

E. Feigin

In this paper we derive two bosonic (alternating sign) formulas for branching functions for general affine Kac-Moody Lie algebra $\g$. Both formulas are given in terms of the Weyl group and string functions of $\g$.

Naoya Enomoto

We determine the composition factors of the polynomial representation of DAHA, conjectured by M. Kasatani. We reduce the determination of composition factors of polynomial representations of DAHA to the determination of the composition factors of the Weyl module $W^{(1^n)}$ for the $v$-Schur algebra. By using the LLT-Ariki type theorem of $v$-Schur algebra p

Christian Borgs, Jennifer Chayes, Elchanan Mossel, Sebastien Roch

We establish the exact threshold for the reconstruction problem for a binary asymmetric channel on the b-ary tree, provided that the asymmetry is sufficiently small. This is the first exact reconstruction threshold obtained in roughly a decade. We discuss the implications of our result for Glauber dynamics, phylogenetic reconstruction, and so-called ``replic