November 2007 arXiv papers — page 37

Carlos Pineda, Thomas H. Seligman

This course aims to introduce the student to random matrix models for decoherence and fidelity decay. They present a very powerful alternate approach, that emphasizes the disordered character of many environments and uncontrollable perturbations/couplings. The inherent integrability of such models makes analytic studies possible. We limit our considerations

Steven C. Pieper

During the last 15 years, there has been much progress in defining the nuclear Hamiltonian and applying quantum Monte Carlo methods to the calculation of light nuclei. I describe both aspects of this work and some recent results.

Ines de Vega, Daniel Alonso

We present a formula to evaluate the spontaneous emission spectra of an atom in contact with a radiation field with non-Markovian effects. This formula is written in terms of a two-time correlation of system observables and the environmental correlation function, and depends on the distance between the emitting atom and the detector. As an example, we use it

N. P. H. Nesvadba, M. D. Lehnert, R. I. Davies, A. Verma

We present spatially-resolved, rest-frame optical spectroscopy of a z~3 Lyman-break galaxy (LBG), Q0347-383 C5, obtained with SINFONI on the VLT. This galaxy, among the ~10% brightest LBGs, is only the second z~3 LBG observed with an integral-field spectrograph. It was first described by Pettini et al. (2001), who obtained WFPC2 F702W imaging and longslit sp

F. Le Pimpec, R. E. Kirby, F. K. King, M. Pivi

The electron cloud effect (ECE) causes beam instabilities in accelerator structures with intense positively charged bunched beams. Reduction of the secondary electron yield (SEY) of the beam pipe inner wall is effective in controlling cloud formation. We summarize SEY results obtained from flat TiN, TiZrV and Al surfaces carried out in a laboratory environme

S. Sridhar, Sitabhra Sinha

The dynamics of activation waves in excitable media can give rise to spiral turbulence, the resulting spatiotemporal chaos being associated with empirical biological phenomena such as life-threatening disturbances in the natural rhythm of the heart. In this paper, we propose a spatially extended but non-global scheme using an array of control points for term

Kai Ji, Keiichiro Nasu

We develop a path-integral theory to study the angle-resolved photoemission spectra (ARPES) of high-T_c superconductors based on a two-dimensional model for the CuO2 conduction plane, including both electron-electron (e-e) and electron-phonon (e-ph) interactions. Comparing our result with the experimental one of Bi2Sr2CaCu2O8, we find that the experimentally

Hudong Chen, Xiaowen Shan

In this paper, we theoretically prove a set of fundamental conditions pertaining discrete velocity sets and corresponding weights. These conditions provide sufficient conditions for a priori formulation of lattice Boltzmann models that automatically admit correct hydrodynamic moments up to any given N-th order.

J. Wan, M. Cahay, S. Bandyopadhyay

We propose and analyze a novel dual-gate Spin Field Effect Transistor (SpinFET) with half-metallic ferromagnetic source and drain contacts. The transistor has two gate pads that can be biased independently. It can be switched ON or OFF with a few mV change in the differential bias between the two pads, resulting in extremely low dynamic power dissipation dur

R. Di Leonardo, F. Saglimbeni, G. Ruocco

Micron-sized objects confined in thin liquid films interact through forces mediated by the deformed liquid-air interface. This capillary interactions provide a powerful driving mechanism for the self-assembly of ordered structures such as photonic materials or protein crystals. Direct probing of capillary interactions requires a controlled force field to ind

Genkai Zhang

Let $X=H/L$ be an irreducible real bounded symmetric domain realized as a real form in an Hermitian symmetric domain $D=G/K$. The intersection $S$ of the Shilov boundary of $D$ with $X$ defines a distinguished subset of the topological boundary of $X$ and is invariant under $H$ and can also be realized as $S=H/P$ for certain parabolic subgroup $P$ of $H$. We

Claude Vallee, Danielle Fortune, Camelia Lerintiu

If the constitutive law linking the second Piola-Kirchhoff stress tensor and the right Cauchy-Green strain tensor derives from a potential, then the Cauchy stress tensor and the logarithm of the left Cauchy-Green strain tensor are linked by a related potential. We give a new and concise proof which is based on an explicit formula expressing the derivative of

Rafał Latała

Motivated by a question of Krzysztof Oleszkiewicz we study a notion of weak tail domination of random vectors. We show that if the dominating random variable is sufficiently regular weak tail domination implies strong tail domination. In particular positive answer to Oleszkiewicz question would follow from the so-called Bernoulli conjecture.

Genkai Zhang

Let $\bbK=\mathbb R, \mathbb C, \mathbb H$ be the field of real, complex or quaternionic numbers and $M_{p, q}(\bbK)$ the vector space of all $p\times q$-matrices. Let $X$ be the matrix unit ball in $M_{n-r, r}(\bbK)$ consisting of contractive matrices. As a symmetric space, $X=G/K=O(n-r, r)/O(n-r)\times O(r)$, $U(n-r, r)/U(n-r)\times U(r)$ and respectively

J. Wan, M. Cahay, S. Bandyopadhyay

We show that a Spin Field Effect Transistor, realized with a semiconductor quantum wire channel sandwiched between half-metallic ferromagnetic contacts, can have Fano resonances in the transmission spectrum. These resonances appear because the ferromagnets are half-metallic, so that the Fermi level can be placed above the majority but below the minority spin

Anton A. Gerasimov, Samson L. Shatashvili

In this paper the relation between 2d topological gauge theories and Bethe Ansatz equations is reviewed. In addition we present some new results and clarifications. We hope the relations discussed here are particular examples of more general relations between quantum topological fields theories in dimensions $d\leq 4$ and quantum integrable systems.

A. Le Fevre, C. Schwarz, G. Auger, M. L. Begemann-Blaich

Correlation functions, constructed from directional projections of the relative velocities of fragments, are used to determine the shape of the breakup volume in coordinate space. For central collisions of 129Xe + natSn at 50 MeV per nucleon incident energy, measured with the 4pi multi-detector INDRA at GSI, a prolate shape aligned along the beam direction w

Artit Hutem, Chanun Sricheewin

The analytical transfer matrix technique is applied to the Schrödinger equation of symmetric quartic-well potential problem in the form $V(x)={1/2}kx^{2}+λ{x^{4}}.$ This gives quantization condition from which we can calculate the ground-state energy eigenvalues numerically. We also compare the results with those obtained from numerical shooting method, pert

Arbab I. Arbab

We have investigated a cosmological model of a phantom energy with a variable cosmological constant ($Λ$) depending on the energy density ($ρ$) as $Λ\propto ρ^{-α}$, $α=\rm const.$ and a variable gravitational constant ($G$). The model requires $α<0$ and a negative gravitational constant. A negative gravitational constant may forbid \emph{black holes} to for

M. Baenninger, A. Ghosh, M. Pepper, H. E. Beere

We report direct experimental evidence that the insulating phase of a disordered, yet strongly interacting two-dimensional electron system (2DES) becomes unstable at low temperatures. As the temperature decreases, a transition from insulating to metal-like transport behaviour is observed, which persists even when the resistivity of the system greatly exceeds

C. Altimiras, U. Gennser, A. Cavanna, D. Mailly

We observed the recently predicted quantum suppression of dynamical Coulomb blockade on short coherent conductors by measuring the conductance of a quantum point contact embedded in a tunable on-chip circuit. Taking advantage of the circuit modularity we measured most parameters used by the theory. This allowed us to perform a reliable and quantitative exper

J. Fabian, A. Matos-Abiague, C. Ertler, P. Stano

Spintronics refers commonly to phenomena in which the spin of electrons in a solid state environment plays the determining role. In a more narrow sense spintronics is an emerging research field of electronics: spintronics devices are based on a spin control of electronics, or on an electrical and optical control of spin or magnetism. This review presents sel

Wolfgang L. Kalb, Fabian Meier, Kurt Mattenberger, Bertram Batlogg

We report on a healing of defects at room temperature in the organic semiconductor pentacene. This peculiar effect is a direct consequence of the weak intermolecular interaction which is characteristic of organic semiconductors. Pentacene thin-film transistors were fabricated and characterized by in situ gated four-terminal measurements. Under high vacuum co

Osamu Saito

We perform a perturbative computation of the glueball superpotential for N=1 supersymmetric G_2 gauge theory with one adjoint matter multiplet. We find that the computation simplifies because the bosonic momentum integral cancels with the fermionic momentum integral. The effective glueball superpotential allows us to gain an insight into non-perturbative asp

Roberto D. Pascual-Marqui

Measures of linear dependence (coherence) and nonlinear dependence (phase synchronization) between any number of multivariate time series are defined. The measures are expressed as the sum of lagged dependence and instantaneous dependence. The measures are non-negative, and take the value zero only when there is independence of the pertinent type. These meas

Kazuyo Tokoi, Kosuke Sato, Yoshitaka Ishisaki, Takaya Ohashi

We present results of 120 ks observation of a compact group of galaxies HCG~62 ($z=0.0145$) with Suzaku XIS and HXD-PIN\@. The XIS spectra for four annular regions were fitted with two temperature {\it vapec} model with variable abundance, combined with the foreground Galactic component. The Galactic component was constrained to have a common surface brightn

S. V. Kozyrev

We discuss the interbasin kinetics approximation for random walk on a complex landscape. We show that for a generic landscape the corresponding model of interbasin kinetics is equivalent to an ultrametric diffusion, generated by an ultrametric pseudodifferential operator on the ultrametric space related to the tree of basins. The simplest example of ultramet

Joerg Reichardt, Michele Leone

We study the problem of recovering a known cluster structure in a sparse network, also known as the planted partitioning problem, by means of statistical mechanics. We find a sharp transition from un-recoverable to recoverable structure as a function of the separation of the clusters. For multivariate data, such transitions have been observed frequently, but

Yves Joly, Elena S. Nazarenko, José-Emilio Lorenzo, Sergio Di Matteo

Resonant X-ray scattering (RXS) is a spectroscopy where both the power of site selective diffraction and the power of local absorption spectroscopy regarding atomic species are combined. By virtue of the dependence on the core level state energy and the three dimensional electronic structure of the intermediate state, this technique is specially suited to st

R. Goto, S. Fujiyama, H. Yano, Y. Nago

The transition to turbulence in the boundary flow of superfluid $^4$He is investigated using a vortex--free vibrating wire. At high wire vibration velocities, we found that stable alternating flow around the wire enters a turbulent phase triggered by free vortex rings. Numerical simulations of vortex dynamics demonstrate that vortex rings can attach to the s

Alex B. Nielsen, Jong Hyuk Yoon

We discuss how the surface gravity can be classically defined for dynamical black holes. In particular we focus on defining the surface gravity for locally defined horizons and compare a number definitions proposed in the literature. We illustrate the differences between the various proposals in the case of an arbitrary dynamical, spherically symmetric black

T. Tanaka, H. Kontani, M. Naito, D. S. Hirashima

We study the intrinsic spin Hall conductivity (SHC) and the $d$-orbital Hall conductivity (OHC) in metallic $d$-electron systems based on the multiorbital tight-binding model. The obtained Hall conductivities are much larger than that in $p$-type semiconductors. The origin of these huge Hall effects is the &#34;effective Aharonov-Bohm phase&#34; induced by t

Wolfgang Mueck

Commutators and anticommutators of gamma matrices with arbitrary numbers of (antisymmetrized) indices are derived.

M. R. Pennington

The PDG Tables list more scalar mesons than can fit into one quark model nonet: indeed, even more than can belong to two multiplets. Consequently, some of these must be states beyond the quark model. So which of these is ${\bar q}q$ or ${\bar{qq}}qq$ or multi-meson molecule or largely glue? How experiment can help us distinguish between these possibilities i

C. Bonatto, E. Bica

The determination of structural parameters of 11 faint Galactic globular clusters that, in most cases, had not been previously studied in this context. The clusters are IC1257, Lynga7, Terzan4, Terzan10, BH176, ESO452-SC11, ESO280-SC08, 2MASS-GC01, 2MASS-GC02, GLIMPSE-C01 and AL3, which are projected not far from the central region of the Galaxy. Field-star

Hashem Zoubi, Helmut Ritsch

We study the resonant electronic excitation dynamics for ultracold atoms trapped in a deep optical lattice prepared in a Mott insulator state. Excitons in these artificial crystals are similar to Frenkel excitons in Noble atom or molecular crystals. They appear when the atomic excited state line width is smaller than the exciton band width generated by dipol

C. Y. Hu, W. J. Munro, J. G. Rarity

We present two novel schemes to generate photon polarization entanglement via single electron spins confined in charged quantum dots inside microcavities. One scheme is via entangled remote electron spins followed by negatively-charged exciton emissions, and another scheme is via a single electron spin followed by the spin state measurement. Both schemes are

Davide Pirro, Maurizio Quadrio

The direct numerical simulation (DNS) of the Taylor--Couette flow in the fully turbulent regime is described. The numerical method extends the work by Quadrio & Luchini (Eur. J. Mech. B / Fluids, v.21, pp.413--427, 2002), and is based on a parallel computer code which uses mixed spatial discretization (spectral schemes in the homogeneous directions, and four

V. G. Bornyakov, S. M. Morozov, Y. Nakamura, M. I. Polikarpov

We present results of finite temperature QCD from N_f=2 flavors of non-perturbatively improved Wilson fermions on lattices with N_t=8, 10 and 12. The transition temperature T_c is determined for the first time at lattice spacings as low as a = 0.08 fm, albeit at pion masses 1.3 < r_0 m_π. We furthermore compute the screening masses in various color channels

Anna N. Morozovska, Sergei V. Svechnikov, Eugene A. Eliseev, Brian J. Rodriguez

The thermodynamics and kinetics of tip-induced polarization switching in Piezoresponse Force Microscopy in the presence of surface charge defects is studied using the combination of analytical and numerical techniques. The signature of the defects in hysteresis loop fine structure and Switching Spectroscopy PFM images is identified and compared to experiment

M. Ndong, L. Bomble, D. Sugny, Y. Justum

We numerically study the implementation of a NOT gate by laser pulses in a model molecular system presenting two electronic surfaces coupled by non adiabatic interactions. The two states of the bit are the fundamental states of the cis-trans isomers of the molecule. The gate is classical in the sense that it involves a one-qubit flip so that the encoding of

Ilham A. Aliev, Boris Rubin, Sinem Sezer, Simten B. Uyhan

We introduce a new concept of the so-called {\it composite wavelet transforms}. These transforms are generated by two components, namely, a kernel function and a wavelet function (or a measure). The composite wavelet transforms and the relevant Calderón-type reproducing formulas constitute a unified approach to explicit inversion of the Riesz, Bessel, Flett,

T. P. Simula, M. J. Davis, P. B. Blakie

We investigate the harmonically trapped interacting Bose gas in a quasi-2D geometry using the classical field method. The system exhibits quasi-long-range order and non-classical rotational inertia at temperatures below the Berezinskii-Kosterlitz-Thouless cross-over to the superfluid state. In particular, we compute the scissors-mode oscillation frequencies

Thomas Timmermann

Finite quantum groupoids can be described in many equivalent ways: In terms of the weak Hopf C*-algebras of Böhm, Nill, and Szlachányi or the finite-dimensional Hopf-von Neumann bimodules of Vallin, and in terms of finite-dimensional multiplicative partial isometries or the finite-dimensional pseudo-multiplicative unitaries of Vallin. In this short note, we

Caroline Champenois, Marion Jacquey, Steven Lepoutre, Matthias Büchner

Two different formulae relating the index of refraction $n$ of gases for atom waves to the scattering amplitude have been published. We show here that these two formulae are not consistent with the definition of the total scattering cross-section while the formula developed by one of us (C.C.) in her thesis is in agreement with this standard knowledge. We di

L. Sunil Chandran, Mathew C. Francis, Santhosh Suresh

A k-dimensional box is the Cartesian product R_1 x R_2 x ... x R_k where each R_i is a closed interval on the real line. The boxicity of a graph G, denoted as box(G) is the minimum integer k such that G is the intersection graph of a collection of k-dimensional boxes. Halin graphs are the graphs formed by taking a tree with no degree 2 vertex and then connec

Steven S. Gubser, Silviu S. Pufu, Amos Yarom

We calculate the far-field stress-energy tensor of a quark gluon plasma due to a heavy-quark meson moving through it, using a semi-classical description in string theory of the meson as a string hanging into anti-de Sitter space. We find that these mesons create a shock wave but no diffusion wake, in contrast to single heavy quarks described via a trailing s

D. Brown, M. Salaris

High precision photometry and spectroscopy of low-mass stars reveal a variety of properties standard stellar evolution cannot predict. Rotation, an essential ingredient of stellar evolution, is a step towards resolving the discrepancy between model predictions and observations. The first rotating stellar model, continuously tracing a low-mass star from the p

Zhi-Bin Zhang, Guang-Zhong Xie

We have tested a relative spectral lag (RSL) method suggested earlier as a luminosity/redshift (or distance) estimator, using the generalized method by Schaefer & Collazzi. We find the derivations from the luminosity/redshift-RSL (L/R-RSL) relation are comparable with the corresponding observations. Applying the luminosity-RSL relation to two different GRB s

Masaru Shibata, Keisuke Taniguchi

We systematically perform the merger simulation of black hole-neutron star (BH-NS) binaries in full general relativity, focusing on the case that the NS is tidally disrupted. We prepare BH-NS binaries in a quasicircular orbit as the initial condition in which the BH is modeled by a nonspinning moving puncture. For modeling the NS, we adopt the $Γ$-law equati

K. Kaneko, A. Schiller

By applying particle-number projection to the static-path approximation (SPA), the heat capacity and the breakdown of pairing correlations are investigated in the thermally excited, superfluid systems 172Yb, 94Mo, and 56Fe. For the heavy nucleus 172Yb, the heat capacities in both the SPA and the number-projected SPA (NPSPA) exhibit an S shape; the difference

Katie Kern, Virginia Kilborn, Duncan Forbes, Baerbel Koribalski

Here we present Australia Telescope Compact Array HI maps of 16 HI sources in six Group Evolution Multiwavelength Study (GEMS) groups that were previously observed with the Parkes telescope. The higher spatial resolution of the ATCA allows us to clearly identify the optical counterparts for the first time -- most being associated with low surface brightness

L. Horvath, R. Fisher, M. J. Collett, H. J. Carmichael

The resonant heating of a harmonically trapped ion by a standing-wave light field is described as a quantum stochastic process combining a coherent Schroedinger evolution with Bohr-Einstein quantum jumps. Quantum and semi-quantum treatments are compared.

Ping-Xing Chen, Shi-Yao Zhu

Many experiments have shown that locality-realism theory is at variance with quantum mechanics predictions. Although locality and realism, which are two different conceptions, are given respective definition, the descriptions of the both are a little of abstract when they are applied to real experimental situations. The abstract descriptions result in diffic

Andrey A. Sukhorukov, C. J. Handmer, C. Martijn de Sterke, M. J. Steel

We consider mode coupling in multimode optical fibers using either two Bragg gratings or a Bragg grating and a long-period grating. We show that the magnitude of the band edge curvature can be controlled leading to a flat, quartic band-edge or to two band edges at distinct, nonequivalent $k$-values, allowing precise control of slow light propagation.

Robert P. Boyer, William M. Y. Goh

Let $p_n$ be the number of partitions of an integer $n$. For each of the partition statistics of counting their parts, ranks, or cranks, there is a natural family of integer polynomials. We investigate their asymptotics and the limiting behavior of their zeros as sets and densities.

Denis Konstantinov, Hanako Isshiki, Hikota Akimoto, Keiya Shirahama

A resonance-induced change in the resistivity of the surface state electrons (SSE) exposed to the microwave (MW) radiation is observed. The MW frequency corresponds to the transition energy between two lowest Rydberg energy levels. All measurements are done with electrons over liquid 3He in a temperature range 0.45-0.65 K, in which the electron relaxation ti

Garnet Kin-Lic Chan, Jonathan J. Dorando, Debashree Ghosh, Johannes Hachmann

The Density Matrix Renormalisation Group (DMRG) is an electronic structure method that has recently been applied to ab-initio quantum chemistry. Even at this early stage, it has enabled the solution of many problems that would previously have been intractable with any other method, in particular, multireference problems with very large active spaces. Histori

Damian F. Abasto, N. Tobias Jacobson, Paolo Zanardi

We explore the finite temperature phase diagram of the anisotropic XY spin chain using the Quantum Chernoff Bound metric on thermal states. The analysis of the metric elements allows to easily identify, in terms of different scaling with temperature, quasi-classical and quantum-critical regions. These results extend recent ones obtained using the Bures metri

David Yong, Frank Grundahl

We present the chemical compositions for eight bright giants in the globular cluster NGC 1851. Our analysis reveals large star-to-star abundance variations and correlations of the light elements O, Na, and Al, a feature found in every well studied globular cluster. However, NGC 1851 also exhibits large star-to-star abundance variations of the s-process eleme

Brant C. Jones

We show that the leading coefficient of the Kazhdan--Lusztig polynomial $P_{x,w}(q)$ known as $μ(x,w)$ is always either 0 or 1 when $w$ is a Deodhar element of a finite Weyl group. The Deodhar elements have previously been characterized using pattern avoidance by Billey--Warrington (2001) and Billey--Jones (2007). In type $A$, these elements are precisely th

Janice C. Lee, Robert C. Kennicutt, Jose G. Funes, S. J.

We examine the connections between the current global star formation activity, luminosity, dynamical mass and morphology of galaxies in the Local Volume, using H-alpha data from the 11 Mpc H-alpha and Ultraviolet Galaxy Survey (11HUGS). Taking the equivalent width (EW) of the H-alpha emission line as a tracer of the specific star formation rate, we analyze t

Huihui An, Chengming Bai

Rota-Baxter algebras were introduced to solve some analytic and combinatorial problems and have appeared in many fields in mathematics and mathematical physics. Rota-Baxter algebras provide a construction of pre-Lie algebras from associative algebras. In this paper, we give all Rota-Baxter operators of weight 1 on complex associative algebras in dimension $\

Chizuru Akizuki, Jun Fukue

We solve spherically symmetric radiation flows under full special relativity with the help of a variable Eddington factor $f(τ, β)$, where $τ$ is the optical depth and $β$ is the flow velocity normalized by the speed of light. Relativistic radiation hydrodynamics under the moment formalism has several complex problems, such as a closure relation. Conventiona

Jun Fukue

Radiative transfer in a relativistic accretion disk wind is examined under the plane-parallel approximation in the fully special relativistic treatment. For an equilibrium flow, where the flow speed and the source function are constant, the emergent intensity is analytically obtained. In such an equilibrium flow the usual limb-darkening effect does not appea

Jun Fukue, Chizuru Akizuki

Accretion disk winds browing off perpendicular to a luminous disk are examined in the framework of fully special relativistic radiation hydrodynamics. The wind is assumed to be steady, vertical, and isothermal. %and the gravitational fields is approximated by a pseudo-Newtonian potential. Using a velocity-dependent variable Eddington factor, we can solve the

Miklós Csörgő, Barbara Szyszkowicz, Qiying Wang

This paper investigates weighted approximations for studentized $U$-statistics type processes, both with symmetric and antisymmetric kernels, only under the assumption that the distribution of the projection variate is in the domain of attraction of the normal law. The classical second moment condition $E|h(X_1,X_2)|^2 < \infty$ is also relaxed in both cases

Miklós Csörgő, Barbara Szyszkowicz, Qiying Wang

Let $X, X_1, X_2,...$ be a sequence of non-degenerate i.i.d. random variables with mean zero. The best possible weighted approximations are investigated in $D[0, 1]$ for the partial sum processes $\{S_{[nt]}, 0\le t\le 1\}$, where $S_n=\sum_{j=1}^nX_j$, under the assumption that $X$ belongs to the domain of attraction of the normal law. The conclusions then

Navin Kashyap

A tree decomposition of the coordinates of a code is a mapping from the coordinate set to the set of vertices of a tree. A tree decomposition can be extended to a tree realization, i.e., a cycle-free realization of the code on the underlying tree, by specifying a state space at each edge of the tree, and a local constraint code at each vertex of the tree. Th

Robert P. Boyer, William M. Y. Goh

Let $F_n(x)$ be the partition polynomial $\sum_{k=1}^n p_k(n) x^k$ where $p_k(n)$ is the number of partitions of $n$ with $k$ parts. We emphasize the computational experiments using degrees up to $70,000$ to discover the asymptotics of these polynomials. Surprisingly, the asymptotics of $F_n(x)$ have two scales of orders $n$ and $\sqrt{n}$ and in three diffe

R. K. Nesbet

The hypothesis is explored that fermion rest mass is due entirely to self-interaction via virtual excitation of gauge bosons. This requires revising the standard model to treat both chiral projections of a fermion field as SU(2) doublets, which precludes Yukawa coupling to a scalar (Higgs) boson field. The estimated self-interaction mass of the electron neut

Christopher F. McKee, Jonathan C. Tan

We consider the radiative feedback processes that operate during the formation of the first stars, including the photodissociation of H_2, Ly-alpha radiation pressure, formation and expansion of an HII region, and disk photoevaporation. These processes may inhibit continued accretion once the stellar mass has reached a critical value, and we evaluate this ma

Wan Yan Wong, Adam Moss, Douglas Scott

The major theoretical limitation for extracting cosmological parameters from the CMB sky lies in the precision with which we can calculate the cosmological recombination process. Uncertainty in the details of hydrogen and helium recombination could effectively increase the errors or bias the values of the cosmological parameters derived from the Planck satel

I. Ya. Aref&#39;eva, L. V. Joukovskaya, S. Yu. Vernov

A general class of cosmological models driven by a nonlocal scalar field inspired by the string field theory is studied. Using the fact that the considering linear nonlocal model is equivalent to an infinite number of local models we have found an exact special solution of the nonlocal Friedmann equations. This solution describes a monotonically increasing U

Ann E. Nelson, Jonathan Walsh

We consider a model of neutrino oscillations with three additional sterile neutrinos and a gauged B-L interaction. We find allowed values of the model parameters which can reconcile the results of the evidence for antimuon neutrino to antielectron neutrino conversion seen at the LSND neutrino oscillation experiment with the null results of the MiniBooNE expe

Christian Rosendal

We investigate extensions of S. Solecki&#39;s theorem on closing off finite partial isometries of metric spaces \cite{solecki1} and obtain the following exact equivalence: any action of a discrete group $Γ$ by isometries of a metric space is finitely approximable if and only if any product of finitely generated subgroups of $Γ$ is closed in the profinite top

Desika Narayanan, Thomas J. Cox, Yancy Shirley, Romeel Dave

We derive a physical model for the observed relations between star formation rate (SFR) and molecular line (CO and HCN) emission in galaxies, and show how these observed relations are reflective of the underlying star formation law. We do this by combining 3D non-LTE radiative transfer calculations with hydrodynamic simulations of isolated disk galaxies and

M. Cervino, V. Luridiana

In general, synthesis models provide the mean value of the distribution of possible integrated luminosities, this distribution (and not only its mean value) being the actual description of the integrated luminosity. Therefore, to obtain the closest model to an observation only provides confi- dence about the precision of such a fit, but not information about

Daniel Grin, Tristan L. Smith, Marc Kamionkowski

It is usually assumed that dark matter is produced during the radiation dominated era. There is, however, no direct evidence for radiation domination prior to big-bang nucleosynthesis. Two non-standard thermal histories are considered. In one, the low-temperature-reheating scenario, radiation domination begins as late as 1 MeV, and is preceded by significant

Christian Rosendal

It is known that there is a comeagre set of mutually conjugate measure preserving homeomorphisms of Cantor space equipped with the coinflipping probability measure, i.e., Haar measure. We show that the generic measure preserving homeomorphism is moreover conjugate to all of its powers. It follows that the generic measure preserving homeomorphism extends to a

Valentin Ferenczi, Christian Rosendal

We prove three new dichotomies for Banach spaces à la W.T. Gowers&#39; dichotomies. The three dichotomies characterise respectively the spaces having no minimal subspaces, having no subsequentially minimal basic sequences, and having no subspaces crudely finitely representable in all of their subspaces. We subsequently use these results to make progress on G

Frank Daniel Steffen

In supersymmetric extensions of the Standard Model, the lightest neutralino, the gravitino, and the axino can appear as the lightest supersymmetric particle and as such provide a compelling explanation of the non-baryonic dark matter in our Universe. For each of these dark matter candidates, I review the present status of primordial production mechanisms, co

Edgar Delgado-Eckert

An n dimensional monomial dynamical system over a finite field K is a nonlinear deterministic time discrete dynamical system with the property that each of the n component functions is a monic nonzero monomial function in n variables. In this paper we provide an algebraic and graph theoretic framework to study the dynamic properties of monomial dynamical sys

Patricia Hersh

This paper proves a conjecture of Fomin and Shapiro that their combinatorial model for any Bruhat interval is a regular CW complex which is homeomorphic to a ball. The model consists of a stratified space which may be regarded as the link of an open cell intersected with a larger closed cell, all within the totally nonnegative part of the unipotent radical o

Brian P. Dolan, Idrish Huet, Sean Murray, Denjoe O&#39;Connor

We present a universal Dirac operator for noncommutative spin and spin^c bundles over fuzzy complex projective spaces. We give an explicit construction of these bundles, which are described in terms of finite dimensional matrices, calculate the spectrum and explicitly exhibit the Dirac eigenspinors. To our knowledge the spin^c spectrum for CP^n with n>=3 is

Matthew G. Brin

Notes for a one semester course. The notes contain a description of compact three dimensional Seifert fibered spaces and a classification up to homeomorphism of compact three dimensional Seifert fibered spaces with non-empty boundary.

Sean Cleary, Murray Elder, Andrew Rechnitzer, Jennifer Taback

We consider random subgroups of Thompson's group $F$ with respect to two natural stratifications of the set of all $k$ generator subgroups. We find that the isomorphism classes of subgroups which occur with positive density are not the same for the two stratifications. We give the first known examples of {\em persistent} subgroups, whose isomorphism classes

Laszlo B. Kish

We hypothesize possible new types of forces that would be the result of new types of interactions, static and a slow transient, between objects with related information contents (pattern). Such mechanism could make material composition dependence claimed by Fishbach, et al in Eotvos type experiments plausible. We carried out experiments by using a high-resol

J. Sabio, L. Borda, F. Guinea, F. Sols

We analyze the phase diagram of a quantum particle confined to a finite chain, subject to a dissipative environment described by an Ohmic spectral function. Analytical and numerical techniques are employed to explore both the perturbative and non-perturbative regime of the model. For small dissipation the coupling to the environment leads to a narrowing of t

Craig J. Fennie

We present a strategy to design structures for which a polar lattice distortion induces weak ferromagnetism. We identify a large class of multiferroic oxides as potential realizations and use density-functional theory to screen several promising candidates. By elucidating the interplay between the polarization and the Dzyaloshinskii-Moriya vector, we show ho

Philippe Gaucher

It is possible to translate a modified version of K. Worytkiewicz&#39;s combinatorial semantics of CCS (Milner&#39;s Calculus of Communicating Systems) in terms of labelled precubical sets into a categorical semantics of CCS in terms of labelled flows using a geometric realization functor. It turns out that a satisfactory semantics in terms of flows requires

N. Brambilla, A. Vairo

We briefly review the theoretical status and the open theoretical challenges in the physics of heavy quarkonium.

Sourin Das, Sumathi Rao, Arijit Saha

We investigate transport properties of a superconducting junction of many ($N \ge 2$) one-dimensional quantum wires. We include the effectofelectron-electron interaction within the one-dimensional quantum wire using a weak interaction renormalization group procedure. Due to the proximity effect, transport across the junction occurs via direct tunneling as we

Carlos O. Lousto, Yosef Zlochower

We present techniques for long-term, stable, and accurate evolutions of multiple-black-hole spacetimes using the `moving puncture&#39; approach with fourth- and eighth-order finite difference stencils. We use these techniques to explore configurations of three black holes in a hierarchical system consisting of a third black hole approaching a quasi-circular

Gavril Farkas

We compute the class of the locus in M_g of curves having a pencil with two unspecified triple ramification points. This is the first example of a geometric divisor on M_g which is not the pull-back of a divisor on the moduli space of pseudo-stable curves. This space, in which elliptic tails are replaced by cusps, appears as a result of the first divisorial

V. N. Soshnikov

We have considered an expansion of solutions of the non-linear equations for both longitudinal and transverse waves in collisionless Maxwellian plasma in series of non-damping overtones of the field E(x,t) and electron velocity distribution function f=f(0) +f(1) where f(0) is background Maxwellian electron distribution function and f(1) is perturbation. The

Ulf Löckmann, Holger Baumgardt

We have developed a new method for post-Newtonian, high-precision integration of stellar systems containing a super-massive black hole (SMBH), splitting the forces on a particle between a dominant central force and perturbations. We used this method to perform fully collisional N-body simulations of inspiralling intermediate-mass black holes (IMBHs) in the c

F. Becattini, F. Piccinini, J. Rizzo

The effects of angular momentum conservation in peripheral heavy ion collisions at very high energy are investigated. It is shown that the initial angular momentum of the quark-gluon plasma should enhance the azimuthal anisotropy of particle spectra (elliptic flow) with respect to the usual picture where only the initial geometrical eccentricity of the nucle

Ananta P. Mishra, Ranjita K. Mohapatra, P. S. Saumia, Ajit M. Srivastava

We focus on the initial state spatial anisotropies, originating at the thermalization stage, for central collisions in relativistic heavy-ion collisions. We propose that a plot of the root mean square values of the flow coefficients $\sqrt{\bar {v_n^2}} \equiv v_n^{rms}$, calculated in a lab fixed coordinate system, for a large range of $n$, from 1 to about

Liljana Babinkostova

We examine the selective screenability property in topological groups. In the metrizable case we also give characterizations in terms of the Haver property and finitary Haver property respectively relative to left-invariant metrics. We prove theorems stating conditions under which the properties are preserved by products. Among metrizable groups we character