arXiv papers from August 2002

A. I. Nesterov, F. Aceves de la Cruz

There are several mathematical and physical reasons why Dirac's quantization must hold. How far one can go without it remains an open problem. The present work outlines a few steps in this direction.

Jeremy Levy

Scalable fault-tolerant quantum computer architectures require quantum gates that operate within a small fraction of the qubit decoherence time and with high accuracy over a bandwidth set by the decoherence rate. Electron spin quantum bits in Si are promising because of long decoherence times (~0.5 ms), but electrical gating schemes still seem problematic. O

U. Nierste

The lifetime splitting between the B^+ and B_d^0 mesons has recently been calculated in the next-to-leading order of QCD. These corrections are necessary for a reliable theoretical prediction, in particular for the meaningful use of hadronic matrix elements computed with lattice QCD. Using results from quenched lattice QCD we find tau(B^+)/tau(B^0_d)=1.053 +

Janos A. Bergou, Ulrike Herzog, Mark Hillery

The problem of quantum state filtering consists of determining whether an unknown quantum state, which is chosen from a known set of states, is either a particular, specified state, or not. We consider this problem for the case that the filtering procedure is required to be unambiguous, which necessitates admitting inconclusive answers when the given states

Stefanie Komossa

We first present a short overview of X-ray probes of the black hole region of active galaxies (AGN) and then concentrate on the X-ray search for supermassive black holes (SMBHs) in optically non-active galaxies. The first part focuses on recent results from the X-ray observatories Chandra and XMM-Newton which detected a wealth of new spectral features which

Gokhan Unel

The investigation of $e \gamma \to \nu W$ process is crucial for a possible high energy $e \gamma$ or $\gamma \gamma$ collider since it offers the possibility for both new physics discovery and precision measurements. The polarization of the initial beam is a limiting factor for the systematic errors in both cases. This note addresses the feasibility of maki

Eduardo S. Tututi, Manuel Torres, Juan Carlos D'Olivo

A first principle derivation is given of the neutrino damping rate in real-time thermal field theory. Starting from the discontinuity of the neutrino self energy at the two loop level, the damping rate can be expressed as integrals over space phase of amplitudes squared, weighted with statistical factors that account for the possibility of particle absorptio

G. Sardanashvily

No bracket determines the evolution operator in covariant (polysymplectic and multisymplectic) Hamiltonian field theory.

Shinji Nonoyama, George Kirczenow

The integer quantum Hall effect (QHE) and one-dimensional Anderson localization (AL) are limiting special cases of a more general phenomenon, directed localization (DL), predicted to occur in disordered one-dimensional wave guides called "quantum railroads" (QRR). Here we explain the surprising results of recent measurements by Kang et al. [Nature 403, 59 (2

L. Mesref

In complete analogy with Seiberg-Witten map defined in noncommutative geometry we introduce a new map between a q-deformed gauge theory and an ordinary gauge theory. The construction of this map is elaborated in order to fit the Hopf algebra structure.

Viv Kendon, Ben Tregenna

We present a study of the effects of decoherence in the operation of a discrete quantum walk on a line, cycle and hypercube. We find high sensitivity to decoherence, increasing with the number of steps in the walk, as the particle is becoming more delocalised with each step. However, the effect of a small amount of decoherence is to enhance the properties of

Hiroaki Arisue, Toshiaki Fujiwara

We propose a new algorithm of the finite lattice method to generate the high-temperature series for the Ising model in three dimensions. It enables us to extend the series for the free energy of the simple cubic lattice from the previous series of 26th order to 46th order in the inverse temperature. The obtained series give the estimate of the critical expon

Oleg Tikhomirov, Hua Jiang, Jeremy Levy

The temperature-dependent polarization of SrTiO_3 thin films is investigated using confocal scanning optical microscopy. A homogeneous out-of-plane and inhomogeneous in-plane ferroelectric phase are identified from images of the linear electrooptic response. Both hysteretic and non-hysteretic behavior are observed under a dc bias field. Unlike classical tran

H. M. Asatrian, K. Bieri, C. Greub, A. Hovhannisyan

We present NNLL results for the double differential decay width dGamma(b -> X_s l+ l-)/(dsh dcos(theta)), where theta is the angle between the momenta of the b-quark and the l+, measured in the rest-frame of the lepton pair. From these results we also derive NNLL results for the lepton forward-backward asymmetries. Genuinely new calculations for the combined

S. R. Beane, M. Malheiro, J. A. McGovern, D. R. Phillips

An effective field theory is used to give a model-independent description of Compton scattering at energies comparable to the pion mass. The amplitudes for scattering on the proton and the deuteron, calculated to fourth order in small momenta in chiral perturbation theory, contain four undetermined parameters that are in one-to-one correspondence with the nu

F. L. Semiao, A. Vidiella-Barranco, J. A. Roversi

We investigate the dynamics of a cold trapped ion coupled to the quantized field inside a high-finesse cavity, considering exact resonance between the ionic internal levels and the field (carrier transition). We derive an intensity-dependent hamiltonian in which terms proportional to the square of the Lamb-Dicke parameter ($\eta$) are retained. We show that

Sanjay M. Wagh, Ravindra V. Saraykar, Keshlan S. Govinder

We argue that a particular spacetime, a spherically symmetric spacetime with hyper-surface orthogonal, radial, homothetic Killing vector, is a physically meaningful spacetime that describes the problem of spherical gravitational collapse in its full "physical" generality.

Hiroyuki Fuji, Katsushi Ito, Yasuhiro Sekino

We investigate the Penrose limit of various brane solutions including Dp-branes, NS5-branes, fundamental strings, (p,q) fivebranes and (p,q) strings. We obtain special null geodesics with the fixed radial coordinate (critical radius), along which the Penrose limit gives string theories with constant mass. We also study string theories with time-dependent mas

Andrew Baker, Andrey Lazarev

We explore two constructions in homotopy category with algebraic precursors in the theory of noncommutative rings and homological algebra, namely the Hochschild cohomology of ring spectra and Morita theory. The present paper provides an extension of the algebraic theory to include the case when $M$ is not necessarily a progenerator. Our approach is complemen

L. Bahmad, A. Benyoussef, H. Ez-Zahraouy

The effect of the surface coupling $J_s$ on the dependency of the layering transition temperature $T_L$ as a function of the thickness $N$, of a spin-1/2 Ising film, is studied using the mean field theory. It is found that for $J_s$ greater than a critical value ($J_{sc}=1.30$), the layering transition temperature decreases when the film thickness $N$ increa

M. Prizzi, K. P. Rybakowski

Let $\Omega$ be an arbitrary smooth bounded domain in $\R^2$ and $\epsilon>0$ be arbitrary. Squeeze $\Omega$ by the factor $\epsilon$ in the $y$-direction to obtain the squeezed domain $\Omega_\epsilon=\{(x,\epsilon y)\mid (x,y)\in\Omega \}$. In this paper we study the family of reaction-diffusion equations $$ \alignedat 2 u_t&=\Delta u+f(u),&\quad &t>0, (x,

J. Hisano

Now the bounds on the lepton-flavor violating (LFV) decay modes of tau lepton are being improved by the Belle experiment in the KEK B factory. In this paper the LFV decay of tau lepton is discussed in the supersymmetric seesaw model, using the current neutrino oscillation data.

Takemi Hayashi, Masato Ito, Masahisa Matsuda, Takeo Matsuoka

In the $SU(6) \times SU(2)_R$ string-inspired model, we evolve the couplings and the masses down from the string scale $M_S$ using the renormalization group equations and minimize the effective potential. This model has the flavor symmetry including the binary dihedral group $\tilde{D}_4$. We show that the scalar mass squared of the gauge non-singlet matter

M. O. Terra Cunha, M. C. Nemes

The complementarity experiment reported in Bertet [{\it{et al.}} (2001), {\it{Nature}} {\bf{411}}, 166.] is discussed. The role played by entanglement in reaching the classical limit is pointed out. Dissipative and thermal effects of the cavity are calculated and a simple modification of the experiment is proposed in order to observe the progressive loss of

Sergei V. Ketov

The non-perturbative quantum geometry of the Universal Hypermultiplet (UH) is investigated in N=2 supergravity. The UH low-energy effective action is given by the four-dimensional quaternionic non-linear sigma-model having an U(1)xU(1) isometry. The UH metric is governed by the single real pre-potential that is an eigenfunction of the Laplacian in the hyperb

Hans Dehmelt

Throughout history, for reasons of health, well known personalities have opted not to eat to satiety - to under-eat - with known benefits. Here, for the benefits of under-eating a very simple explanation is offered and discussed in some detail. Our distant ancestors, whose bodies we inherited, ate and weighed a good deal less than we do. They had to run arou

S. Rigamonti, F. A. Reboredo, C. R. Proetto

A recently developed quasi two-dimensional exact-exchange formalism within the framework of Density Functional Theory has been applied to a strongly inhomogeneous interacting electron gas, and the results were compared with state-of-the-art Variational Quantum Monte Carlo (VMC) numerical simulations for a three-dimensional electron gas under a strong externa

C. Reichhardt, C. J. Olson Reichhardt, I. Martin, A. R. Bishop

We examine the dynamics and stripe formation in a system with competing short and long range interactions in the presence of both an applied dc drive and quenched disorder. Without disorder, the system forms stripes organized in a labyrinth state. We find that, when the disorder strength exceeds a critical value, an applied dc drive can induce a dynamical st

M. Q. Weng, M. W. Wu

We set up a set of many-body kinetic Bloch equations with spacial inhomogeneity. We reexamine the widely adopted quasi-independent electron model (QIEM) and show the inadequacy of this model in studying the spin transport. We further point out a new decoherence effect based on interference effect of electrons/spins with different momentum ${\bf k}$ along the

E. Schinnerer, N. Z. Scoville

We have detected four Giant Molecular cloud Associations (GMAs) (sizes < 6.6'' ~ 430 pc) in the western and eastern region of the polar ring in NGC2685 (the Helix galaxy) using the Owens Valley Radio Observatory (OVRO) millimeter interferometer. Emission from molecular gas is found close to the brightest Halpha and HI peaks in the polar ring and is confirmed

Fan Chung, Linyuan Lu, T. Gregory Dewey, David J. Galas

Are biological networks different from other large complex networks? Both large biological and non-biological networks exhibit power-law graphs (number of nodes with degree k, N(k) ~ k-b) yet the exponents, b, fall into different ranges. This may be because duplication of the information in the genome is a dominant evolutionary force in shaping biological ne

Henry Scudder, Gang Lu, Nicholas Kioussis

The chemisorption of atomic hydrogen on the single-walled armchair carbon nanotube is studied with ab initio calculations. A single H atom is found to be chemisorbed on both the inside and outside wall of the nanotube. The binding energy of H adsorption at the exterior of the nanotube is much greater than that at the interior of the nanotube. For the first t

Bo Reipurth, Cathie Clarke

We discuss a scenario in which brown dwarfs are formed like stars, except that their full collapse phases are interrupted through dynamical interactions in small multiple systems, leading to the ejection of the lightest member. This disintegration is a stochastic process, often resulting in the expulsion of newborn low mass stars, but when it occurs early en

David W. Hogg

A meta-analysis is performed of the literature on evolution in cosmic star-formation rate density from redshift unity to the present day. The measurements are extremely diverse, including radio, infrared, and ultraviolet broad-band photometric indicators, and visible and near-ultraviolet line-emission indicators. Although there is large scatter among indicat

Ulvi Yurtsever

Can the apparent complexity we observe in the real world be generated from simple initial conditions via simple, deterministic rules?

D. A. Demir, Tony Gherghetta, Keith A. Olive

In models where the Standard Model spectrum is localized on a brane embedded in a higher dimensional spacetime, we discuss the lepton number violation induced by the emission of right-handed neutrinos from the brane. We show that quite generically the presence of the right-handed neutrinos in the bulk leads to rapid lepton number violating processes which ab

E. T. Tomboulis

We consider correlation inequalities that follow from the well-known loop equations of LGT, and their analogues in spin systems. They provide a way of bounding long range by short or intermediate range correlations. In several cases the method easily reproduces results that otherwise require considerable effort to obtain. In particular, in the case of the 2-

Yasser Rathore, Avery E. Broderick, Roger Blandford

We present a variational formalism for describing the dynamical evolution of an oscillating star with a point-mass companion in the linear, non-relativistic regime. This includes both the excitation of normal modes and the back-reaction of the modes on the orbit. The general formalism for arbitrary fluid configurations is presented, and then specialized to a

Jiri Vanicek, Eric J. Heller

We find a uniform semiclassical (SC) wave function describing coherent branched flow through a two-dimensional electron gas (2DEG), a phenomenon recently discovered by direct imaging of the current using scanned probed microscopy. The formation of branches has been explained by classical arguments, but the SC simulations necessary to account for the coherenc

M. R. Ahmady, F. A. Chishtie, V. Elias, A. H. Fariborz

QCD contributions to the $b \to u \ell^- \bar{\nu}_\ell$ decay rate, which are known to two-loop order in the $\bar{MS}$ scheme, exhibit sufficient dependence on the renormalization mass $\mu$ to compromise phenomenological predictions for inclusive semileptonic $B \to X_u$ processes. Such scale dependence is ameliorated by the renormalization-group (RG) ext

Sebastian Wolf, Hubert Klahr

We investigate the possibility of mapping large-scale anti-cyclonic vortices, resulting from a global baroclinic instability, as pre-cursors of planet formation in proto-planetary disks with the planned Atacama Large Millimeter Array (ALMA). On the basis of three-dimensional radiative transfer simulations, images of a hydrodynamically calculated disk are der

Yong-Seon Song, Asantha Cooray, Lloyd Knox, Matias Zaldarriaga

The intervening large--scale structure distorts cosmic microwave background (CMB) anisotropies via gravitational lensing. The same large--scale structure, traced by dusty star--forming galaxies, also induces anisotropies in the far--infrared background (FIRB). We investigate the resulting inter--dependence of the FIRB and CMB with a halo model for the FIRB.

S. Picozzi, R. Asahi, C. B. Geller, A. J. Freeman

The technologically important problem of predicting Auger recombination lifetimes in semiconductors is addressed by means of a fully first--principles formalism. The calculations employ highly precise energy bands and wave functions provided by the full--potential linearized augmented plane wave (FLAPW) code based on the screened exchange local density appro

Julia Gordon, Thomas C. Hales

The Langlands-Shelstad transfer factor is a function defined on some reductive groups over a p-adic field. Near the origin of the group, it may be viewed as a function on the Lie algebra. For classical groups, its values have the form q^c s, where s is -1, 0, or 1, q is the cardinality of the residue field, and c is a rational number. The function s partitio

W. P. Bowen, R. Schnabel, P. K. Lam, T. C. Ralph

We generate a pair of entangled beams from the interference of two amplitude squeezed beams. The entanglement is quantified in terms of EPR-paradox [Reid88] and inseparability [Duan00] criteria, with observed results of $\Delta^{2} X_{x|y}^{+} \Delta^{2} X_{x|y}^{-} = 0.58 \pm 0.02$ and $\sqrt{\Delta^{2} X_{x \pm y}^{+} \Delta^{2} X_{x \pm y}^{-}} = 0.44 \pm

Felix Lev

We consider elementary particles in a quantum theory based on a Galois field. In this approach infinities cannot exist, the cosmological constant problem does not arise and one irreducible representation of the symmetry algebra necessarily describes a particle and its antiparticle simultaneously. {\it In other words, the very existence of antiparticles is a

A. Dumitru, R. D. Pisarski

We sketch an effective theory for the deconfined state of QCD near Tc. This relates the behavior of the expectation value of the Polyakov loop, and its two-point functions, to the pressure. Defining the ``mass'' of three and two gluon states from the imaginary and real parts of the Polyakov loop, while this ratio is 3:2 in perturbation theory, at Tc it is 3:

Shuichi Murakami, Naoto Nagaosa

The colossal magnetoresistance in manganites AMnO_3 is studied from the viewpoint of multicritical phenomena. To understand the complicated interplay of various phases, we study the Ginzburg-Landau theory in terms of both the mean-field approximation and the renormalization-group analysis to compare with the observed phase diagram. Several novel features, su

Shuichi Murakami, Naoto Nagaosa

In magnetic systems, electronic bands often acquire nontrivial topological structure characterized by gauge flux distribution in momentum (k)-space. It sometimes follows that the phase of the wavefunctions cannot be defined uniquely over the whole Brillouin zone. In this Letter we develop a theory of superconductivity in the presence of this gauge flux both

Demosthenes Kazanas, Markos Georganopoulos, Apostolos Mastichiadis

We propose that the internal energy of the GRB blast waves, thought to be stored in the form of relativistic protons co-moving with the blast wave, is converted explosively (i.e. on light crossing time scales) into relativistic electrons of the same Lorentz factor, which are responsible for the production of observed prompt gamma-ray emission of the burst. T

Joel H. Kastner, Lara Crigger, Margaret Rich, David A. Weintraub

We present archival ROSAT data for three recently identified, nearby (D<70 pc), young (~10-40 Myr) stellar associations: the TW Hydrae Association, the Tucana-Horologium Association, and the beta Pic Moving Group. The distributions of ROSAT X-ray hardness ratios (HR1, HR2) for these three groups, whose membership is dominated by low-mass, weak-lined T Tauri

Z. L. Xiao, Catherine Y. Han, U. Welp, H. H. Wang

Large area nickel antidot arrays with density up to 10^10 /cm^2 have been fabricated by depositing nickel onto anodic aluminum oxide membranes that contain lattices of nanopores. Electron microscopy images show a high degree of order of the antidot arrays. Various sizes and shapes of the antidots were observed with increasing thickness of the deposited nicke

C. Greiner

Sufficiently fast chemical equilibration of (strange) antibaryons in an environment of nucleons, pions and kaons during the course of a relativistic heavy ion collision can be understood by a `clustering' of mesons to build up baryon-antibaryon pairs. This multi-mesonic (fusion-type) process has to exist in medium due to the principle of detailed balance. No

Jian-Ge Zhou

We construct the string states $|O_{p}^J>_J$, $|O_{q}^{J_1}>_{{J_1}{J_2}}$ and $|O_{0}^{J_{1}J_{2}}>_{{J_1}{J_2}}$ in the Hilbert space of the quantum mechanical orbifold model so as to calculate the three point functions and the matrix elements of the light-cone Hamiltonian from the interacting string bit model. With these string states we show that the thr

Richard L. Hall, Qutaibeh D. Katatbeh

This paper is concerned with the discrete spectra of Schroedinger operators H = -Delta + V, where V(r) is an attractive potential in N spatial dimensions. Two principal results are reported for the bottom of the spectrum of H in each angular-momentum subspace H_{ell}: (i) an optimized lower bound when the potential is a sum of terms V(r) = V^{(1)}(r) + V^{(2

Antonio Enea Romano, Charles Goebel

A simple group theoretic derivation is given of the family of space-time metrics with isometry group SO(2,1) X SO(2) X R first described by Godel, of which the Godel stationary cosmological solution is the member with a perfect-fluid stress-energy tensor. Other members of the family are shown to be interpretable as cosmological solutions with a electrically

Xin Wan, Kun Yang, Chenggang Zhou, R. N. Bhatt

We study quantum spin-1/2 Heisenberg ferromagnetic chains with dilute, random antiferromagnetic impurity bonds with modified spin-wave theory. By describing thermal excitations in the language of spin waves, we successfully observe a low-temperature Curie susceptibility due to formation of large spin clusters first predicted by the real-space renormalization

Eugene Tevelev

We define and study several equivariant stratifications of the isotropy and coisotropy representations of a parabolic subgroup in a complex reductive group.

Alfred H. Mueller

The relationship between RHIC and HERA data is explored using the idea of saturation (color glass condensate) as a unifying framework for interpretation. A description of the early stages of a heavy ion collision is given with the RHIC results. The relevant QCD dynamics at the various stages of a heavy ion collision, from production of gluons to equilibratio

T. Barnes, N. Black, P. R. Page

In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resona

David J. Gross, Andrei Mikhailov, Radu Roiban

Berenstein, Maldacena, and Nastase have proposed, as a limit of the strong form of the AdS/CFT correspondence, that string theory in a particular plane wave background is dual to a certain subset of operators in the N=4 super-Yang-Mills theory. Even though this is a priori a strong/weak coupling duality, the matrix elements of the string theory Hamiltonian,

Arup Banerjee, Manoranjan P. Singh

We study the effect of going beyond the Gross-Pitaevskii theory on the frequencies of collective oscillations of a trapped Bose gas in the large gas parameter regime. We go beyond the Gross-Pitaevskii regime by including a higher-order term in the interatomic correlation energy. To calculate the frequencies we employ the sum-rule approach of many-body respon

Andres Meza

The stability of rotating isotropic spherical stellar systems is investigated by using N-body simulations. Four spherical models with realistic density profiles are studied: one of them fits the luminosity profile of globular clusters, while the remaining three models provide good approximations to the surface brightness of elliptical galaxies. The phase-spa

Todd A. Brun, Hilary A. Carteret, Andris Ambainis

We look at two possible routes to classical behavior for the discrete quantum random walk on the line: decoherence in the quantum ``coin'' which drives the walk, or the use of higher-dimensional coins to dilute the effects of interference. We use the position variance as an indicator of classical behavior, and find analytical expressions for this in the long

C. Blume

The large acceptance and high momentum resolution as well as the significant particle identification capabilities of the NA49 experiment at the CERN SPS allow for a broad study of fluctuations and correlations in hadronic interactions. In the first part recent results on event-by-event charge and p_t fluctuations are presented. Charge fluctuations in central

Howard Baer, Tadas Krupovnickas

The radiative decay Z2-> Z1 gamma proceeds at the one-loop level in the MSSM. It can be the dominant decay mode for the second lightest neutralino Z2 in certain regions of parameter space of supersymmetric models, where either a dynamical and/or kinematic enhancement of the branching fraction occurs. We perform an updated numerical study of this decay mode i

F. Pignatelli, A. V. Ustinov

We present experimental observation of broken-symmetry states in a superconducting loop with three Josephson junctions. These states are generic for discrete breathers in Josephson ladders. The existence region of the breather-like states is found to be in good accordance with the theoretical expectations. We observed three different resonant states in the c

D. J. Fixsen, P. G. A. Mirel, A. Kogut, M. Seiffert

The thermometer and thermal control system, for the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) experiment, is described, including the design, testing, and results from the first flight of ARCADE. The noise is equivalent to about 1 Omega or 0.15 mK in a second for the RuO_2 resistive thermometers at 2.7 K. The average powe

C. D. Batista, J. Bonča, J. E. Gubernatis

We introduce a novel mechanism for itinerant ferromagnetism, based on a simple two-band model. The model includes an uncorrelated and dispersive band hybridized with a second band which is narrow and correlated. The simplest Hamiltonian containing these ingredients is the Periodic Anderson Model (PAM). Using quantum Monte Carlo and analytical methods, we sho

Patrick B. Greene, Kenji Kadota, Hitoshi Murayama

We present a realistic supergravity inflation model which is free from the overproduction of potentially dangerous relics in cosmology, namely moduli and gravitinos which can lead to the inconsistencies with the predictions of baryon asymmetry and nucleosynthesis. The radiative correction turns out to play a crucial role in our analysis which raises the mass

Martin Porrmann

The notion of Wigner particles is attached to irreducible unitary representations of the Poincare group, characterized by parameters m and s of mass and spin, respectively. However, the Lorentz symmetry is broken in theories with long-range interactions, rendering this approach inapplicable (infraparticle problem). A unified treatment of both particles and i

C. L. Kane, Matthew P. A. Fisher

We analyze theoretically a three-terminal geometry in a fractional quantum Hall system - studied in a recent experiment - which allows a dilute beam of Laughlin quasiparticles to be prepared and subsequently scattered by a point contact. Employing a chiral Luttinger liquid description of the nu^{-1} = m integer edge states, we compute the current and noise o

B. Lucini, M. Teper, U. Wenger

We report on our ongoing investigation of the deconfining phase transition in SU(4) and SU(6) gauge theories. We calculate the critical couplings while taking care to avoid the influence of a nearby bulk phase transition. We determine the latent heat of the phase transition and investigate the order and the strength of the transition at large N. We also repo

Sergey V. Barabash, David Stroud

We discuss the low-frequency absorption arising from quenched inhomogeneity in the superfluid density rho_s of a model superconductor. Such inhomogeneities may arise in a high-T_c superconductor from a wide variety of sources, including quenched random disorder and static charge density waves such as stripes. Using standard classical methods for treating ran

H. -G. Ludwig, F. Allard, P. H. Hauschildt

Based on detailed 2D and 3D numerical radiation-hydrodynamics (RHD) simulations of time-dependent compressible convection, we have studied the dynamics and thermal structure of the convective surface layers of a prototypical late-type M-dwarf (Teff~2800K log(g)=5.0, solar chemical composition). The RHD models predict stellar granulation qualitatively similar

In Sook Park

Let $\mathbb{G}$ be a locally compact abelian group and let $1<p\leq 2$. $\mathbb{G}^{'}$ is the dual group of $\mathbb{G}$, and $p^{'}$ the conjugate exponent of $p$. An operator $T$ between Banach spaces $X$ and $Y$ is said to be compatible with the Fourier transform $F^{\mathbb{G}}$ if $F^{\mathbb{G}}\otimes T: L_p(\mathbb{G})\otimes X\to L_{p^{'}}(\mathb

Oisin A. P. Mac Conamhna

We compute the boundary two point functions of operators corresponding to massive spin 1 and spin 2 de Sitter fields, by an extension of the ``S-Matrix'' approach developed for bulk scalars. In each case the two point functions are of the form required for conformal invariance of the dual boundary field theory. We emphasise that in the context of dS/CFT one

Axel Grabowski, Tilman Pfau

We describe basic periodic trapping configurations for ultracold atoms above surfaces. The approach is based on a simple wire grid and can be scaled to provide large arrays of periodically arranged magnetic or magneto-optical traps. The unit cells of the trap lattices are based on crossed wire segments. By alternating the current directions in the wires of t

R. Harrison, I. Moroz, K. P. Tod

We present a numerical study of the time-dependent SN equations in 3 dimensions with 3 different kinds of symmetry: spherically symmetric, axially symmetric and translationally symmetric. We find that the solutions manifest the competing tendencies of dispersion from the Schrodinger equation and gravitational attraction from the Poisson equation. Only the gr

Aarno Hohti

We investigate the connection between the spatiality of locale products and the earlier studies of the author on the locally fine coreflection of the products of uniform spaces. After giving a historical introduction and indicating the connection between spatiality and the locally fine construction, we indicate how the earlier results directly solve the firs

R. Harrison, I. Moroz, K. P. Tod

We consider the linear stability of the spherically-symmetric stationary solutions of the Schrodinger-Newton equations. We find that the ground state is linearly stable, with only imaginary eigenvalues, while the n-th excited state has n quadruples of complex eigenvalues as well as purely imaginary ones and so is linearly unstable.

H. Beuther, J. Kerp, T. Preibisch, T. Stanke

We report the detection of hard X-ray emission (>2 keV) from a number of point sources associated with the very young massive star-forming region IRAS 19410+2336. The X-ray emission is detected from several sources located around the central and most deeply embedded mm continuum source, which remains undetected in the X-ray regime. All X-ray sources have K-b

Gregory J. Galloway

The null splitting theorem (proved in math.DG/9909158) is discussed. As an application, a uniqueness theorem for Minkowski space and for de Sitter space associated with the occurrence of null lines (inextendible globally achronal null geodesics) is presented.

L. Monaco, F. R. Ferraro, M. Bellazzini, E. Pancino

We present V, I photometry of the Sagittarius Dwarf Spheroidal galaxy (Sgr) for a region of ~ 1^{circ} times 1^{circ}, centered on the globular cluster M 54. This catalog is the largest database of stars (~500,000) ever obtained for this galaxy. The wide area covered allows us to measure for the first time the position of the RGB-bump, a feature that has bee

A. Kirchberg, J. D. Laenge, P. A. G. Pisani, A. Wipf

In this paper the N=2 supersymmetric extension of the Schroedinger Hamiltonian with 1/r-potential in arbitrary space-dimensions is constructed. The supersymmetric hydrogen atom admits a conserved Laplace-Runge-Lenz vector which extends the rotational symmetry SO(d) to a hidden SO(d+1) symmetry. This symmetry of the system is used to determine the discrete ei

M. B. d'Arcy, R. M. Godun, D. Cassettari, G. S. Summy

We experimentally demonstrate a method for selecting small regions of phase space for kicked rotor quantum chaos experiments with cold atoms. Our technique uses quantum accelerator modes to selectively accelerate atomic wavepackets with localized spatial and momentum distributions. The potential used to create the accelerator mode and subsequently realize th

Z. Sroczynski

We present results for the performance of QCD code on ALiCE, the Alpha-Linux Cluster Engine at Wuppertal. We describe the techniques employed to optimise the code, including the metaprogramming of assembler kernels, the effects of data layout and an investigation into the overheads incurred by the communication.

Gerard Clement, Dmitri Gal'tsov, Cedric Leygnac

We present new solutions to Einstein-Maxwell-dilaton-axion (EMDA) gravity in four dimensions describing black holes which asymptote to the linear dilaton background. In the non-rotating case they can be obtained as the limiting geometry of dilaton black holes. The rotating solutions (possibly endowed with a NUT parameter) are constructed using a generating t

M. Guidal, M. Vanderhaeghen

We study the double deeply virtual Compton scattering (DDVCS) process off the nucleon, through the scattering of a spacelike virtual photon with large virtuality resulting in the production of a timelike virtual photon, decaying into an e^+ e^- pair. This process is expressed in the Bjorken regime in terms of generalized parton distributions (GPDs) and it is

Jan Philip Solovej, Wolfgang L. Spitzer

We introduce new coherent states and use them to prove semi-classical estimates for Schr\"odinger operators with regular potentials. This can be further applied to the Thomas-Fermi potential yielding a new proof of the Scott correction for molecules.

A. Helmstetter, D. Sornette

As part of an effort to develop a systematic methodology for earthquake forecasting, we use a simple model of seismicity based on interacting events which may trigger a cascade of earthquakes, known as the Epidemic-Type Aftershock Sequence model (ETAS). The ETAS model is constructed on a bare (unrenormalized) Omori law, the Gutenberg-Richter law and the idea

Z. Fodor, S. D. Katz, K. K. Szabo

In this letter we give the equation of state of QCD at finite temperatures and densities. The recently proposed overlap improving multi-parameter reweighting technique is used to determine observables at nonvanishing chemical potentials. Our results are obtained by studying n_f=2+1 dynamical staggered quarks with semi-realistic masses on N_t=4 lattices.

Meirav Amram, Mina Teicher, Muhammed Uludag

In this paper we obtain presentations of fundamental groups of the complements of three quadric-line arrangements in P^2. The first arrangement is a smooth quadric Q with n tangent lines to Q, and the second one is a quadric Q with n lines passing through a point p not in Q. The last arrangement consists of a quadric Q with n lines passing through a point p

Michael Malquarti, Andrew R. Liddle

We carry out a comprehensive study of the dynamics of large-scale perturbations in quintessence scenarios. We model the contents of the Universe by a perfect fluid with equation of state w_f and a scalar field Q with potential V(Q). We are able to reduce the perturbation equations to a system of four first-order equations. During each of the five main regime

Gerard Clement, Dmitri Gal'tsov

We complete the list of fluxbrane solutions in classical supergravities by introducing Melvin type space-times supported by antisymmetric forms of rank $D-1$ and their pseudoscalar duals. In IIB theory these solutions belong to the same family as the seven-brane and D-instanton. In current notation, a fluxbrane supported by the D-1 form is an F0 brane, its e

J. M. Deharveng, A. Boselli, J. Donas

We have assembled a UV-flux selected sample of 82 early-type galaxies and collected additional information at other wavelengths. These data confirm a large spread of the UV-V color in the range 2 to 5. The spread in UV-V is accompanied by a spread in B-V that is mainly attributed to the range of morphological types and luminosities. A large fraction of the o

John B. Kogut

I review present challenges that QCD in extreme environments presents to lattice gauge theory. Recent data and impressions from RHIC are emphasized. Physical pictures of heavy ion wavefunctions, collisions and the generation of the Quark Gluon Plasma are discussed, with an eye toward engaging the lattice and its numerical methods in more interaction with the

Tom A. Kuusela, Tony Shepherd, Jarmo Hietarinta

Normal human heart rate shows complex fluctuations in time, which is natural, since heart rate is controlled by a large number of different feedback control loops. These unpredictable fluctuations have been shown to display fractal dynamics, long-term correlations, and 1/f noise. These characterizations are statistical and they have been widely studied and u

Michael Steiner, R. W. Rendell

It is predicted by Schrodinger's equation that entanglement will occur in the interaction between detector and particle. We provide an analysis of the entanglement using the Gurvitz model of double-dot and detector. New results on entangled doubled-dots are provided as well as implications on Quantum Information processing.

M. Bouhmadi-Lopez, P. F. Gonzalez-Diaz, A. Zhuk

By considering 5--dimensional cosmological models with a bulk filled with a pressureless scalar field; equivalently dust matter, and a negative cosmological constant, we have found a regular instantonic solution which is free from any singularity at the origin of the extra--coordinate. This instanton describes 5--dimensional asymptotically anti de Sitter wor