December 2008 arXiv papers — page 49

Rami Atar, Amarjit Budhiraja

A two-player stochastic differential game representation has recently been obtained for solutions of the equation -Δ_\infty u=h in a \calC^2 domain with Dirichlet boundary condition, where h is continuous and takes values in \RR\setminus\{0\}. Under appropriate assumptions, including smoothness of u, the vanishing δlimit law of the state process, when both p

Mihai Cipu, Maurice Mignotte

We study the solutions of a Diophantine equation of the form $a^x+b^y=c^z$, where $a\equiv 2 \pmod 4$, $b\equiv 3 \pmod 4$ and $\gcd (a,b,c)=1$. The main result is that if there exists a solution $(x,y,z)=(2,2,r)$ with $r>1$ odd then this is the only solution in integers greater than 1, with the possible exception of finitely many values $(c,r)$. We also pro

Marco Congedo, Cédric Gouy-Pailler, Christian Jutten

Over the last ten years blind source separation (BSS) has become a prominent processing tool in the study of human electroencephalography (EEG). Without relying on head modeling BSS aims at estimating both the waveform and the scalp spatial pattern of the intracranial dipolar current responsible of the observed EEG. In this review we begin by placing the BSS

B. J. Dabrowska-Wuester, S. Wuester, M. J. Davis

We model the dynamics of formation of multiple, long-lived, bright solitary waves in the collapse of Bose-Einstein condensates with attractive interactions as studied in the experiment of Cornish et al. [Phys. Rev. Lett. 96 (2006) 170401]. Using both mean-field and quantum field simulation techniques, we find that while a number of separated wave packets for

Peter Bro Miltersen

It is NP-hard to decide if a given pure-strategy Nash equilibrium of a given three-player game in strategic form with integer payoffs is trembling hand perfect.

D. Koester, S. O. Kepler, S. J. Kleinman, A. Nitta

The DA white dwarfs in the Sloan Digital Sky Survey, as analyzed in the papers for Data Releases 1 and 4, show an increase in surface gravity towards lower effective temperatures below 11500 K. We study the various possible explanations of this effect, from a real increase of the masses to uncertainties or deficiencies of the atmospheric models. No definite

Romuald Lenczewski

We show that the operatorial framework developed by Voiculescu for free random variables can be extended to arrays of random variables whose multiplication imitates matricial multiplication. The associated notion of independence, called matricial freeness, can be viewed as a generalization of both freeness and monotone independence. At the same time, the sum

V. V. Prudskikh

The propagation of ion-acoustic solitons in a warm dusty plasma containing two ion species is investigated theoretically. Using an approach based on the Korteveg-de-Vries equation, it is shown that the critical value of the negative ion density that separates the domains of existence of compressi- on and rarefaction solitons depends continuously on the dust

Vladimir Gurvich, Peter Bro Miltersen

We consider some well-known families of two-player, zero-sum, perfect information games that can be viewed as special cases of Shapley's stochastic games. We show that the following tasks are polynomial time equivalent: - Solving simple stochastic games. - Solving stochastic mean-payoff games with rewards and probabilities given in unary. - Solving stoch

V. V. Prudskikh

The propagation of weakly nonlinear dust--acoustic waves in a dusty plasma containing two ion species with different temperatures is explored. The nonlinear equations describing both the quadratic and cubic plasma nonlinearities are derived. It is shown that the properties of dust--acoustic waves depend substantially on the grain size distribution. In partic

Christian Corda

The production of a stochastic background of relic gravitational waves is well known in various works in the literature, where, using the so called adiabatically-amplified zero-point fluctuations process it has been shown how the standard inflationary scenario for the early universe can in principle provide a distinctive spectrum of relic gravitational waves

Detlev Koester

We describe the spectral classification of white dwarfs and some of the physical processes important for their understanding. In the major part of this paper we discuss the input physics and computational methods for one of the most widely used stellar atmosphere codes for white dwarfs.

Charles Vial

We show that operations in Milnor K-theory mod $p$ of a field are spanned by divided power operations. After giving an explicit formula for divided power operations and extending them to some new cases, we determine for all fields $k$ and all prime numbers $p$, all the operations $K^M_i/p \to K^M_j/p$ commuting with field extensions over the base field $k$.

Jiang Dong, Na Wang

Since mid-2005, a pulsar searching system has been operating at 18 cm on the 25-m radio telescope of Urumqi Observatory. Test observations on known pulsars show that the system can perform the intended task. The prospect of using this system to observe 3EG sources and other target searching tasks is discussed.

T. L. Riethmueller, S. K. Solanki, V. Zakharov, A. Gandorfer

We present a 106-minute TiO (705.7nm) time series of high spatial and temporal resolution that contains thousands of umbral dots (UDs) in a mature sunspot in the active region NOAA 10667 at $μ$=0.95. The data were acquired with the 1-m Swedish Solar Telescope on La Palma. With the help of a multilevel tracking (MLT) algorithm the sizes, brightnesses, and tra

Gerard Ascensi

The paper study the discrete sets of translations of the Gaussian function that span the spaces L1(R) and L2(R).

A. V. Dodonov

We study theoretically the nonstationary circuit QED system in which the artificial atom transition frequency, or the atom-cavity coupling, have a small periodic time modulation, prescribed externally. The system formed by the atom coupled to a single cavity mode is described by the Rabi Hamiltonian. We show that, in the dispersive regime, when the modulatio

K. Sridhar

The production cross-section of h_c, the 1P_1 charmonium state, can be predicted in Non-Relativistic QCD (NRQCD) using heavy-quark symmetry. We show that at the Large Hadron Collider a large cross-section for this resonance is predicted and it should be possible to look for the h_c through it decay into J/psi +pi even with the statistics that will be achieve

W. Ishibashi, T. J. -L. Courvoisier

We consider the fuelling of the central massive black hole in Active Galactic Nuclei, through an inhomogeneous accretion flow. Performing simple analytical treatments, we show that shocks between elements (clumps) forming the accretion flow may account for the UV and X-ray emission in AGNs. In this picture, a cascade of shocks is expected, where optically th

M. S. Laad

Motivated by the experimental finding of Ferromagnetism (FM) near non-FL quantum phase transitions (QPT), I investigate FM in an Extended Periodic Anderson Model (EPAM). Using the Frobenius-Perron theorem, a FM {\it metallic} phase near the selective Mott localization is rigorously found. Interesting connections with Tasaki's flat-band ferromagnetism, as

N. Besson

Although often quoted as a discovery collider, the LHC will also allow for precise measurements. In particular, in the electroweak sector, the determination of the masses of the top quark and the W boson will benefit from high statistics and new methods.

A. P. Kobushkin, D. L. Borisyuk

We discuss effects of two-photon exchange (TPE) in various observables of the elastic ep-scattering. The imaginary part of the TPE amplitude manifests in target and beam normal spin asymmetries. The real part contributes to the cross-section. A model-independent phenomenological analysis of experimental data is performed. Its results are compared with theore

Santanu K. Maiti

We explore a novel mechanism for control of periodicity in persistent current in a twisted normal metal loop threaded by a magnetic flux $ϕ$. A simple tight-binding model is used to describe the system. Quite interestingly we see that, depending on the number of twist $p$, the persistent current exhibits $ϕ_0/p$ ($ϕ_0=ch/e$, the elementary flux-quantum) peri

Jörn Dunkel, Peter Hänggi, Stefan Weber

Rules for the transformation of time parameters in relativistic Langevin equations are derived and discussed. In particular, it is shown that, if a coordinate-time parameterized process approaches the relativistic Juttner-Maxwell distribution, the associated proper-time parameterized process converges to a modified momentum distribution, differing by a facto

Hirotaka Yoshino

We study a static black hole localized on a brane in the Randall-Sundrum (RS) II braneworld scenario. To solve this problem numerically, we develop a code having the almost 4th-order accuracy. This code derives the highly accurate result for the case where the brane tension is zero, i.e., the spherically symmetric case. However, a nonsystematic error is dete

Carlo Albert, Bea Bleile, Jürg Fröhlich

The Batalin-Vilkovisky method (BV) is the most powerful method to analyze functional integrals with (infinite-dimensional) gauge symmetries presently known. It has been invented to fix gauges associated with symmetries that do not close off-shell. Homological Perturbation Theory is introduced and used to develop the integration theory behind BV and to descri

J. Kaspar, M. Rysavy

Single channel measurements play a minor role in today physics, but they are sometimes unavoidable. Comparing to multichannel measurements, there is distribution of measurement time to be chosen in an experiment design. A method to optimize distribution of measurement time is given, where optimal distribution minimizes standard deviation of a selected fit pa

J. Wabnig, B. W. Lovett

We present the theory of a single spin meter consisting of a quantum dot in a magnetic field under microwave irradiation combined with a charge counter. We show that when a current is passed through the dot, a change in the average occupation number occurs if the microwaves are resonant with the on-dot Zeeman splitting. The width of the resonant change is gi

M. Das, C. S. Reynolds, S. N. Vogel, S. S. McGaugh

We present Chandra detections of x-ray emission from the AGN in two giant Low Surface Brightness (LSB) galaxies, UGC 2936 and UGC 1455. Their x-ray luminosities are 1.8\times10^{42} ergs/s and 1.1\times10^{40} ergs/s respectively. Of the two galaxies, UGC 2936 is radio loud. Together with another LSB galaxy UGC 6614 (XMM archival data) both appear to lie abo

Emil Saucan, Meir Katchalski

We provide an alternative, simpler proof of the existence of thick triangulations for noncompact $\mathcal{C}^1$ manifolds. Moreover, this proof is simpler than the original one given in \cite{pe}, since it mainly uses tools of elementary differential topology. The role played by curvatures in this construction is also emphasized.

S. Mark, C. Gould, K. Pappert, J. Wenisch

We report the discovery of an effect where two ferromagnetic materials, one semiconductor ((Ga,Mn)As) and one metal (permalloy), can be directly deposited on each other and still switch their magnetization independently. We use this independent magnetization behavior to create various resistance states dependent on the magnetization direction of the individu

G. Roper Yearwood, B. Beischer, Ch. -H. Chung, Ph. v. Doetinchem

We present a prototype for the first tracking detector consisting of 250 micron thin scintillating fibers and silicon photomultiplier (SiPM) arrays. The detector has a modular design, each module consists of a mechanical support structure of 10mm Rohacell foam between two 100 micron thin carbon fiber skins. Five layers of scintillating fibers are glued to bo

Wolfgang-Michael Schulz, Robert Rossbach, Matthias Reischle, Gareth J. Beirne

Systematic ensemble photoluminescence studies have been performed on type-I InP-quantum dots in Al0.20Ga0.80InP barriers, emitting at approximately 1.85 eV at 5 K. The influence of different barrier configurations as well as the incorporation of additional tunnel barriers on the optical properties has been investigated. The confinement energy between the dot

P. Beirão, P. N. Appleton, B. R. Brandl, M. Seibert

We present new mid-infrared ($5 - 35μ$m) and ultraviolet (1539 -- 2316 Å) observations of the interacting galaxy system Arp 143 (NGC 2444/2445) from the Spitzer Space Telescope and GALEX. In this system, the central nucleus of NGC 2445 is surrounded by knots of massive star-formation in a ring-like structure. We find unusually strong emission from warm H$_2$

Mstislav Elagin

The paper offers a unified approach to the study of three locally adaptive estimation methods in the context of univariate time series from both theoretical and empirical points of view. A general procedure for the computation of critical values is given. The underlying model encompasses all distributions from the exponential family providing for great flexi

S. Berceanu, A. Gheorghe

Infinitesimal holomorphic realizations for the Schrödinger-Weil representation and the discrete series representations of the Jacobi group are constructed. Explicit expressions of the basic differential operators are obtained. The squeezed states for the unitary irreducible representation of the Jacobi group are introduced. Matrix elements of the squeezed op

Arvind Ayyer, Doron Zeilberger

We attempt to prove the Razumov-Stroganov conjecture using a bijectional approach. We have been unsuccessful but we believe the techniques we present can be used to prove the conjecture.

J. Guzowski, B. Cichocki, E. Wajnryb, G. C. Abade

The short--time self diffusion coefficient of a sphere in a suspension of rigid rods is calculated in first order in the rod volume fraction. For low rod concentrations the correction to the Einstein diffusion constant of the sphere is a linear function of the rod volume fraction with the slope proportional to the equilibrium averaged mobility diminution tra

Parviz Sahandi

Let $D$ be an integral domain and $\star$ a semistar operation stable and of finite type on it. In this paper, we are concerned with the study of the semistar (Krull) dimension theory of polynomial rings over $D$. We introduce and investigate the notions of $\star$-universally catenarian and $\star$-stably strong S-domains and prove that, every $\star$-local

Robert Cori

Hypermaps were introduced as an algebraic tool for the representation of embeddings of graphs on an orientable surface. Recently a bijection was given between hypermaps and indecomposable permutations; this sheds new light on the subject by connecting a hypermap to a simpler object. In this paper, a bijection between indecomposable permutations and labelled

Sabu M. Thampi

Knowledge has been lately recognized as one of the most important assets of organizations. Managing knowledge has grown to be imperative for the success of a company. This paper presents an overview of Knowledge Management and various aspects of secure knowledge management. A case study of knowledge management activities at Tata Steel is also discussed

A. M. Bloch, O. E. Fernandez, T. Mestdag

We introduce a method which allows one to recover the equations of motion of a class of nonholonomic systems by finding instead an unconstrained Hamiltonian system on the full phase space, and to restrict the resulting canonical equations to an appropriate submanifold of phase space. We focus first on the Lagrangian picture of the method and deduce the corre

Ricky Ini Liu

We introduce a Littlewood-Richardson rule based on an algorithmic deformation of skew Young diagrams and present a bijection with the classical rule. The result is a direct combinatorial interpretation and proof of the geometric rule presented by Coskun. We also present a corollary regarding the Specht modules of the intermediate diagrams.

Z. W. Yu, X. T. Ni, L. C. Kwek, X. B. Wang

We study the feasibility of implementing a quantum NOT gate (approximate) when the quantum state lies between two latitudes on the Bloch's sphere and present an analytical formula for the optimized 1-to-$M$ quantum NOT gate. Our result generalizes previous results concerning quantum NOT gate for a quantum state distributed uniformly on the whole Bloch sp

Jun-ichiro Ohe, Yoshihiro Tomoda, Nejat Bulut, Ryotaro Arita

We present a realistic study for electronic and magnetic properties in dilute magnetic semiconductor (Ga,Mn)As. A multi-orbital Haldane-Anderson model parameterized by density-functional calculations is presented and solved with the Hirsch-Fye quantum Monte Carlo algorithm. Results well reproduce experimental results in the dilute limit. When the chemical po

D. Z. Xu, H. Ian, T. Shi, H. Dong

Hermann Feshbach predicted fifty years ago that when two atomic nuclei are scattered within an open entrance channel-- the state observable at infinity, they may enter an intermediate closed channel -- the locally bounded state of the nuclei. If the energy of a bound state of in the closed channel is fine-tuned to match the relative kinetic energy, then the

Lei Bai, George H. Rieke, Marcia J. Rieke, Daniel Christlein

We present MIPS observations of the cluster A3266. About 100 spectroscopic cluster members have been detected at 24 micron. The IR luminosity function in A3266 is very similar to that in the Coma cluster down to the detection limit L_IR~10^43 ergs/s, suggesting a universal form of the bright end IR LF for local rich clusters with M~10^15 M_sun. The shape of

S. C. Lim, L. P. Teo

We study the zero and finite temperature Casimir force acting on a perfectly conducting piston with arbitrary cross section moving inside a closed cylinder with infinitely permeable walls. We show that at any temperature, the Casimir force always tends to move the piston away from the walls and towards its equilibrium position. In the case of rectangular pis

Ayumu Inoue

We show that the hyperbolic volume of a hyperbolic knot is a quandle cocycle invariant. Further we show that it completely determines invertibility and positive/negative amphicheirality of hyperbolic knots.

H. -P. Breuer, E. Göklü, C. Lämmerzahl

Recently a model of metric fluctuations has been proposed which yields an effective Schrödinger equation for a quantum particle with a modified inertial mass, leading to a violation of the weak equivalence principle. The renormalization of the inertial mass tensor results from a local space average over the fluctuations of the metric over a fixed background

K. H. O. Hasnaoui, Ph. Chomaz, F. Gulminelli

A new Fermionic Molecular Dynamics (FMD) model based on a Skyrme functional is proposed in this paper. After introducing the basic formalism, some first applications to nuclear structure and nuclear thermodynamics are presented

I. C. Cloet, G. Eichmann, B. El-Bennich, T. Klahn

A dressed-quark core contribution to nucleon electromagnetic form factors is calculated. It is defined by the solution of a Poincare' covariant Faddeev equation in which dressed-quarks provide the elementary degree of freedom and correlations between them are expressed via diquarks. The nucleon-photon vertex involves a single parameter; i.e., a diquark charg

Cristina Ballantine, Dorin Ghisa

A visualization of Blaschke product mappings can be obtained by treating them as canonical projections of covering Riemann surfaces and finding fundamental domains and covering transformations corresponding to these surfaces. A working tool is the technique of simultaneous continuation we introduced in previous papers. Here, we are refining this technique fo

Xiao-Yong Jin, Robert D. Mawhinney

We report on simulations of QCD with many flavors of degenerate quarks, the DBW2 gauge action and naive staggered fermions, using the rational hybrid Monte Carlo algorithm. We primarily focus on eight degenerate quark flavors where a variety of values of the coupling constant and quark mass have been used in the simulations. The scaling behavior of the hadro

Ales Drapal, Michael Kinyon

Let $Q$ be a Buchsteiner loop. We describe the associator calculus in three variables, and show that $|Q| \ge 32$ if $Q$ is not conjugacy closed. We also show that $|Q| \ge 64$ if there exists $x \in Q$ such that $x^2$ is not in the nucleus of $Q$. Furthermore, we describe a general construction that yields all proper Buchsteiner loops of order 32. Finally,

Huey-Wen Lin

I review recent lattice calculations of hyperon physics, including hyperon spectroscopy, axial coupling constants, form factors and semileptonic decays.

Aaron Worley, Plamen G. Krastev, Bao-An Li

Gravitational waves are tiny disturbances in space-time and are a fundamental, although not yet directly confirmed, prediction of General Relativity. Rapidly rotating neutron stars are one of the possible sources of gravitational radiation dependent upon pulsar's rotational frequency, details of the equation of state of stellar matter, and distance to de

R. Hales, H. Waalkens

We study the quantum transport through entropic barriers induced by hardwall constrictions of hyperboloidal shape in two and three spatial dimensions. Using the separability of the Schrodinger equation and the classical equations of motion for these geometries we study in detail the quantum transmission probabilities and the associated quantum resonances, an

T. Baba, T. Yokoya, S. Tsuda, T. Watanabe

We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy to directly observe the large superconducting (SC) gap anisotropy (GA) of YNi2B2C. The result shows large SC GA with a smooth variation along an intersection of a Fermi surface (FS) around the $Γ$-Z line and nearly isotropic SC gap values for two intersections of FSs around the

Mary Beth Ruskai, Elisabeth M. Werner

We show that a bipartite state on a tensor product of two matrix algebras is almost surely entangled if its rank is not greater than that of one of its reduced density matrices.

Tomas Brauner

We investigate the thermodynamics of a pion gas within the O(N) model in the 1/N expansion. Using the auxiliary field technique, we compute the effective potential up to the next-to-leading order (NLO) and show that it can be renormalized in a temperature-independent manner. The crucial step for the consistency of the calculation turns out to be the eliminat

E. H. Hwang, S. Das Sarma

We develop a theory for graphene magnetotransport in the presence of carrier spin polarization as induced, for example, by the application of an in-plane magnetic field ($B$) parallel to the 2D graphene layer. We predict a negative magnetoresistance $σ\propto B^2$ for intrinsic graphene, but for extrinsic graphene we find a non-monotonic magnetoresistance wh

Ming-Che Chang, Min-Fong Yang

We study the magnetization for the classical antiferromagnetic Ising model on the Shastry-Sutherland lattice using the tensor renormalization group approach. With this method, one can probe large spin systems with little finite-size effect. For a range of temperature and coupling constant, a single magnetization plateau at one third of the saturation value i

Timur Zh. Esirkepov, Sergei V. Bulanov, Alexei G. Zhidkov, Alexander S. Pirozhkov

A novel ultra-bright high-intensity source of X-ray and gamma radiation is suggested. It is based on the double Doppler effect, where a relativistic flying mirror reflects a counter-propagating electromagnetic radiation causing its frequency multiplication and intensification, and on the inverse double Doppler effect, where the mirror acquires energy from an

Friedwardt Winterberg

Large scale manned space flight within the solar system is still confronted with the solution of two problems: 1. A propulsion system to transport large payloads with short transit times between different planetary orbits. 2. A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion

Yaroslav V. Kartashov, Victor A. Vysloukh, Lluis Torner

We address the evolution of higher-order excited states, such as vortex and multi-hump solitons, in nonlocal media with synthetic, competing focusing and defocusing nonlinearities with different nonlocal transverse scales. We reveal that introduction of suitable competing effects makes possible the stabilization of vortex solitons with topological charge m>2

Stanley J. Brodsky, Felipe J. Llanes-Estrada, Adam P. Szczepaniak

The local coupling of two photons to the fundamental quark currents of a hadron gives an energy-independent contribution to the Compton amplitude proportional to the charge squared of the struck quark, a contribution which has no analog in hadron scattering reactions. We show that this local contribution has a real phase and is universal, giving the same con

Andrew M. Childs, Wim van Dam

Quantum computers can execute algorithms that dramatically outperform classical computation. As the best-known example, Shor discovered an efficient quantum algorithm for factoring integers, whereas factoring appears to be difficult for classical computers. Understanding what other computational problems can be solved significantly faster using quantum algor

Mark Vogelsberger, Amina Helmi, Volker Springel, Simon D. M. White

We study predictions for dark matter phase-space structure near the Sun based on high-resolution simulations of six galaxy halos taken from the Aquarius Project. The local DM density distribution is predicted to be remarkably smooth; the density at the Sun differs from the mean over a best-fit ellipsoidal equidensity contour by less than 15% at the 99.9% con

Christian Bourdarias, Mehmet Ersoy, Stéphane Gerbi

The aim of this paper is to present a kinetic numerical scheme for the computations of transient pressurised flows in closed water pipes with variable sections. Firstly, we detail the derivation of the mathematical model in curvilinear coordinates under some hypothesis and we performe a formal asymptotic analysis. Then the obtained system is written as a con

François Germinet, Abel Klein, Jeffrey H. Schenker

We prove quantization of the Hall conductance for continuous ergodic Landau Hamiltonians under a condition on the decay of the Fermi projections. This condition and continuity of the integrated density of states are shown to imply continuity of the Hall conductance. In addition, we prove the existence of delocalization near each Landau level for these two-di

Douglas J. Ballon, Henning U. Voss

The behavior of coupled harmonic oscillators in systems with specified boundary conditions is typically characterized by resonances whose frequency spectra represent harmonics according to properties of the individual oscillators, the interactions between them, and the overall symmetry of the system. Here it is demonstrated that classical one- and two-dimens

Dirk Blomker, Wei Wang

The qualitative properties of local random invariant manifolds for stochastic partial differential equations with quadratic nonlinearities and multiplicative noise is studied by a cut off technique. By a detail estimates on the Perron fixed point equation describing the local random invariant manifold, the structure near a bifurcation is given.

Stefanie Jegelka, Suvrit Sra, Arindam Banerjee

In the past few years powerful generalizations to the Euclidean k-means problem have been made, such as Bregman clustering [7], co-clustering (i.e., simultaneous clustering of rows and columns of an input matrix) [9,18], and tensor clustering [8,34]. Like k-means, these more general problems also suffer from the NP-hardness of the associated optimization. Re

Kevin Buchin

We present a new and simple randomized algorithm for constructing the Delaunay triangulation using nearest neighbor graphs for point location. Under suitable assumptions, it runs in linear expected time for points in the plane with polynomially bounded spread, i.e., if the ratio between the largest and smallest pointwise distance is polynomially bounded. Thi

E. O'Sullivan, S. Giacintucci, J. M. Vrtilek, S. Raychaudhury

We use a deep Chandra observation to examine the structure of the hot intra-group medium of the compact group of galaxies Stephan's Quintet. The group is thought to be undergoing a strong dynamical interaction as an interloper, NGC 7318b, passes through the group core at ~850 km/s. A bright ridge of X-ray and radio continuum emission has been interpreted

Michael Levin, Bertrand I. Halperin

Motivated by the physics of the Moore-Read ν= 1/2 state away from half-filling, we investigate collective states of non-abelian e/4 quasiparticles in a magnetic field. We consider two types of collective states: incompressible liquids and Wigner crystals. In the incompressible liquid case, we construct a natural series of states which can be thought of as a

F. Governato, C. B. Brook, A. M. Brooks, L. Mayer

Using high resolution SPH simulations in a fully cosmological Lambda CDM context we study the formation of a bright disk dominated galaxy that originates from a "wet" major merger at z=0.8. The progenitors of the disk galaxy are themselves disk galaxies that formed from early major mergers between galaxies with blue colors. A substantial thin stellar

Qingfeng Li, Jan Steinheimer, Hannah Petersen, Marcus Bleicher

A systematic study of HBT radii of pions, produced in heavy ion collisions in the intermediate energy regime (SPS), from an integrated (3+1)d Boltzmann+hydrodynamics approach is presented. The calculations in this hybrid approach, incorporating an hydrodynamic stage into the Ultra-relativistic Quantum Molecular Dynamics transport model, allow for a compariso

O. Kochukhov

Pulsational variability is observed in several types of main sequence stars with anomalous chemical abundances. In this contribution I summarize the relationship between pulsations and chemical peculiarities, giving special emphasis to rapid oscillations in magnetic Ap stars. These magneto-acoustic pulsators provide unique opportunities to study the interact

Diego Gallego, Marco Serone

We study under what conditions massive fields can be &#34;frozen&#34; rather than integrated out in certain four dimensional theories with global or local N=1 supersymmetry. We focus on models without gauge fields, admitting a superpotential of the form W = W0(H) + epsilon W1(H,L), with epsilon << 1, where H and L schematically denote the heavy and light chi

Diana Battefeld, Thorsten Battefeld

We examine a wide class of multi-field inflationary models based on fields that decay or stabilize during inflation in a staggered fashion. The fields driving assisted inflation are on flat, short stretches, before they encounter a sharp drop; whenever a field encounters such a drop due to its slow roll evolution, its energy is transferred to other degrees o

Avery E. Broderick, Abraham Loeb

The silhouette cast by the horizon of the supermassive black hole in M87 can now be resolved with the emerging millimeter very-long baseline interferometry (VLBI) capability. Despite being ~2000 times farther away than SgrA* (the supermassive black hole at the center of the Milky-Way and the primary target for horizon-scale imaging), M87's much larger black

Akshay K. Kulkarni, Marina M. Romanova

We investigate the photometric variability of magnetized stars, particularly neutron stars, accreting through a magnetic Rayleigh-Taylor-type instability at the disk-magnetosphere interface, and compare it with the variability during stable accretion, with the goal of looking for possible quasi-periodic oscillations. The lightcurves during stable accretion s

Andres Collinucci

In this note, a procedure is developed to explicitly construct non-trivial F-theory lifts of perturbative IIB orientifold models on Calabi-Yau complete intersections in toric varieties. This procedure works on Calabi-Yau orientifolds where the involution coordinate can have arbitrary projective weight, as opposed to the well-known hypersurface cases where it

Keith S. M. Lee, Frank J. Tackmann

Recently, it was shown that in inclusive B -> Xs l+ l- decay, an angular decomposition provides three independent (q^2 dependent) observables. A strategy was formulated to extract all measurable Wilson coefficients in B -> Xs l+ l- from a few simple integrals of these observables in the low q^2 region. The experimental measurements in the low q^2 region requ

Alex Borisov, Bhuvnesh Jain

Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the universe. We calculate quasilinear effects in the growth of structure in f(R) models of gravity using perturbation theory. We find significant deviations in the bispectrum that depend on cosmic time, length scale and triangle shape. Howe

Daniel C. Fabrycky, Ruth A. Murray-Clay

A new era of directly imaged extrasolar planets has produced a three-planet system (Marois et al. 2008), where the masses of the planets have been estimated by untested cooling models. We point out that the nominal circular, face-on orbits of the planets lead to a dynamical instability in ~10^5 yr, a factor of at least 100 shorter than the estimated age of t

M. J. Bhaseen, M. Hohenadler, A. O. Silver, B. D. Simons

Motivated by recent experiments on cold atomic gases in ultra high finesse optical cavities, we consider the problem of a two-band Bose--Hubbard model coupled to quantum light. Photoexcitation promotes carriers between the bands and we study the non-trivial interplay between Mott insulating behavior and superfluidity. The model displays a global U(1) X U(1)

Eung Jin Chun, Jong-Chul Park

Motivated by the recent PAMELA and ATIC data, one is led to a scenario with heavy vector-like dark matter in association with a hidden $U(1)_X$ sector below GeV scale. Realizing this idea in the context of gauge mediated supersymmetry breaking (GMSB), a heavy scalar component charged under $U(1)_X$ is found to be a good dark matter candidate which can be sea

L. Calibbi, L. Ferretti, A. Romanino, R. Ziegler

We show that most features of the mass and mixing pattern of the second and third SM fermion families can be accounted for without making use of flavour symmetries or other types of flavour dynamics. We discuss the implications for flavour phenomenology, in particular for the $τ\toμγ$ decay rate, and comment on LFV effects at colliders. We show that the mode

Charles Nash, Denjoe O&#39;Connor

We show that the zero temperature phase diagram of the vortex free sector of the Kitaev model is in one to one correspondence with that of the classical dimer model on the same lattice. We find that the model generically has three distinct phases. On a honeycomb lattice with a $3\times3$ fundamental domain all three phases are accessible. As the couplings ar

Richard C. Brower, Marko Djurić, Chung-I Tan

At high energies, elastic hadronic cross sections, such as $pp, \overline p p, \pi^{\pm} p$, are dominated by vacuum exchange, which in leading order of the $1/N_c$ expansion has been identified as the BFKL Pomeron or its strong AdS dual the closed string Reggeized graviton \cite{Brower:2006ea}. However the difference of particle anti-particle cross sections

Y. C. Zou, T. Piran, R. Sari

The extremely bright optical flash that accompanied GRB 080319B suggested, at first glance, that the prompt $γ$-rays in this burst were produced by Synchrotron self Compton (SSC). We analyze here the observed optical and $γ$ spectrum. We find that the very strong optical emission poses, due to self absorption, very strong constraints on the emission processe

Jacques Bloch, Tilo Wettig

Motivated by the important role played by the phase of the fermion determinant in the investigation of the sign problem in lattice QCD at nonzero baryon density, we derive an analytical formula for the average phase factor of the fermion determinant for general topology in the microscopic limit of chiral random matrix theory at nonzero chemical potential, fo

Benjamin Hsu, Michael Mulligan, Eduardo Fradkin, Eun-Ah Kim

We study the scaling behavior of the entanglement entropy of two dimensional conformal quantum critical systems, i.e. systems with scale invariant wave functions. They include two-dimensional generalized quantum dimer models on bipartite lattices and quantum loop models, as well as the quantum Lifshitz model and related gauge theories. We show that, under qu

Benoit Charbonneau, Jacques Hurtubise

In this paper, the moduli space of singular unitary Hermitian--Einstein monopoles on the product of a circle and a Riemann surface is shown to correspond to a moduli space of stable pairs on the Riemann surface. These pairs consist of a holomorphic vector bundle on the surface and a meromorphic automorphism of the bundle. The singularities of this automorphi

Ramon van Handel

We prove that bootstrap type Monte Carlo particle filters approximate the optimal nonlinear filter in a time average sense uniformly with respect to the time horizon when the signal is ergodic and the particle system satisfies a tightness property. The latter is satisfied without further assumptions when the signal state space is compact, as well as in the n

Steven Weinstein

Bell&#39;s theorem is purported to demonstrate the impossibility of a local &#34;hidden variable&#34; theory underpinning quantum mechanics. It relies on the well-known assumption of `locality&#39;, and also on a little-examined assumption called `statistical independence&#39; (SI). Violations of this assumption have variously been thought to suggest &#34;ba

S. Graser, T. A. Maier, P. J. Hirschfeld, D. J. Scalapino

Weak-coupling approaches to the pairing problem in the iron pnictide superconductors have predicted a wide variety of superconducting ground states. We argue here that this is due both to the inadequacy of certain approximations to the effective low-energy band structure, and to the natural near-degeneracy of different pairing channels in superconductors wit