February 2009 arXiv papers — page 42

M. L. Keptsyna, A. Le Breton, M. Viot

Filtering problems with general exponential quadratic criteria are investigated for Gauss-Markov processes. In this setting, the Linear Exponential Gaussian and Risk-Sensitive filtering problems are solved and it is shown that they may have different solutions.

D. Chekulaev, A. Kaplan

We have investigated ultrafast carriers dynamics in crystalline silicon nano-pillars structure using a pump-probe reflectivity method with 800 nm, 150 fs laser pulses and fluence in the range of {17 - 170} mJ/cm^2. Dimensions of the structure allow us to eliminate contribution from the diffusion process to the relaxation dynamics of the excited carriers. Str

Michael Mazilu

Lorentz's reciprocity lemma and Feld-Tai reciprocity theorem show the effect of interchanging the action and reaction in Maxwell's equations. We derive a free-space version of these reciprocity relations which generalizes the conservation of the momentum-energy tensor. This relation corresponds to the interference conservation of electromagnetic wave

Felix Kalischewski, Andreas Heuer

Full nucleation control for deposited functional molecules on pre-patterned surfaces is of major technological relevance. To understand the nucleation behavior we combine the numerical solution for the evolution of the adatom concentration with standard nucleation theory. From the qualitative change in nucleation behavior upon variation of the pattern spacin

K. Boutsia, B. Leibundgut, D. Trevese, F. Vagnetti

Luminous AGNs are usually selected by their non-stellar colours or their X-ray emission. Colour selection cannot be used to select low-luminosity AGNs, since their emission is dominated by the host galaxy. Objects with low X-ray to optical ratio escape even the deepest X-ray surveys performed so far. In a previous study we presented a sample of candidates se

T. J. Humanic

A simple model based on relativistic geometry and final-state hadronic rescattering is used to predict pion source parameters extracted in two-pion femtoscopy studies of proton-proton collisions at s**(1/2) = 200 GeV. From studying the momentum and particle multiplicity dependences of these parameters in the context of this model and assuming a very short ha

J. P. Badiali

Starting from an algebraic approach of quantum physics it has been shown via the Tomita-Takesaki theorem and the KMS condition that the canonical density matrix contains the dynamics of the system provided we use a rescaling of time. In this paper we show that the path integral form of the partition function reveals a dynamics which is complementary of the o

G. Matt, S. Bianchi, H. Awaki, A. Comastri

In recent years, several Seyfert 2 galaxies have been discovered that change state when observed in X-rays a few years apart, switching from Compton-thin to reflection-dominated or viceversa. We observed a member of this class of "Changing-look" sources, the Phoenix Galaxy, with Suzaku, with the aim of better understanding the nature of the variation

N. J. O. Silva, A. Millan, F. Palacio, E. Kampert

We show that antiferromagnetic susceptibility in ferritin increases with temperature between 4.2 K and 180 K (i. e. below the Néel temperature) when taken as the derivative of the magnetization at high fields ($30\times10^4$ Oe). This behavior contrasts with the decrease in temperature previously found, where the susceptibility was determined at lower fields

Xin Zhang, Jingfei Zhang, Jinglei Cui, Li Zhang

In this paper we discuss the inflationary universe in the context of a Chaplygin gas equation of state within the framework of the effective theory of loop quantum cosmology. Under the slow-roll approximation, we calculate the primordial perturbations for this model. We give the general expressions of the scalar spectral index, its running, and the tensor-to

Christian Bartsch, Jochen Gemmer

We show that the vast majority of all pure states featuring a common expectation value of some generic observable at a given time will yield very similar expectation values of the same observable at any later time. This is meant to apply to Schroedinger type dynamics in high dimensional Hilbert spaces. As a consequence individual dynamics of expectation valu

Yassine Ariba, Frédéric Gouaisbaut, Sandy Rahme, Yann Labit

Several studies have considered control theory tools for traffic control in communication networks, as for example the congestion control issue in IP (Internet Protocol) routers. In this paper, we propose to design a linear observer for time-delay systems to address the traffic monitoring issue in TCP/AQM (Transmission Control Protocol/Active Queue Managemen

Pierre-Olivier Mattei

This study deals with spectral analysis of fluid-loaded vibrating structure. It was recently observed in a numerical study on a high order perturbation method under heavy fluid loading that a loaded vibrating plate results, not only in the classical frequency shift of the in vacuo single resonance (in both the real part because of the fluid added mass and th

Ivan Jureta, John Mylopoulos, Stephane Faulkner

A requirements engineering artifact is valid relative to the stakeholders of the system-to-be if they agree on the content of that artifact. Checking relative validity involves a discussion between the stakeholders and the requirements engineer. This paper proposes (i) a language for the representation of information exchanged in a discussion about the relat

Michel Balazard, Oswaldo Velásquez Castañón

The greatest lower bound of the real parts of the roots of a partial sum of the Dirichlet series of Riemann's zeta function is asymptotically equivalent to the opposite of the number of terms of this sum, multiplied by the Napierian logarithm of 2, when this number of terms tends to infinity.

Yann Labit, Yassine Ariba, Frédéric Gouaisbaut

For the last few years, we assist to a growing interest of designing AQM (Active Queue Management) using control theory. In this paper, we focus on the synthesis of an AQM based on the Lyapunov theory for time delay systems. With the help of a recently developed Lyapunov-Krasovskii functional and using a state space representation of a linearized fluid model

Yassine Ariba, Yann Labit, Frédéric Gouaisbaut

Recent research has shown the link between congestion control in communication networks and feedback control system. In this paper, the design of an active queue management (AQM) which can be viewed as a controller, is considered. Based on a state space representation of a linearized fluid flow model of TCP, the AQM design is converted to a state feedback sy

Yassine Ariba, Frédéric Gouaisbaut, Yann Labit

This paper investigates the overload problem of a single congested router in TCP (Transmission Control Protocol) networks. To cope with the congestion phenomenon, we design a feedback control based on a multiple time-delays model of the set TCP/AQM (Active Queue Management). Indeed, using robust control tools, especially in the quadratic separation framework

Rainer Burghardt

The Reissner-Nordstroem metric is re-examined and supplemented with an interior solution. Both metrics are embedded in a 5-dimensional flat space.

Fabiola M. A. Ribeiro, Marcos P. Diaz

Flickering is a phenomenon related to the mass accretion observed among many classes of astrophysical objects. In this paper we present a study of the flickering emission lines and continuum of the Cataclysmic Variable V3885 Sgr. The flickering behavior is first analyzed through statistical analysis and lightcurves power spectra. Autocorrelation techniques a

S. Ord, L. Greenhill, R. Wayth, D. Mitchell

The MWA is a next-generation radio interferometer under construction in remote Western Australia. The data rate from the correlator makes storing the raw data infeasible, so the data must be processed in real-time. The processing task is of order ~10 TFLOPS. The remote location of the MWA limits the power that can be allocated to computing. We describe the d

Jaroslaw Klos

This paper presents electronic spectra of zigzag and armchair graphene nanoribbons calculated within the tight-binding model for pi-electrons. Zigzag and armchair nanoribbons of different edge geometries are considered, with surface perturbation taken into account. The properties of surface states are discussed on the basis of their classification into Tamm

M. L. Pumo, P. Ventura, F. D'Antona, R. A. Zappala'

Super-AGB stars can conclude their evolution either as neon-oxygen white dwarfs or as electron-capture supernovae. We discuss the possible consequences of the existence of this "double final fate" in the self-enrichment of globular clusters and in the nucleosynthesis process of s-nuclei.

Wrick Sengupta

A new analytical operator method is discussed which solves linear ordinary differential equations with regular singularities. Solutions are obtained in analytic series form and also in Mellin-Barnes-type contour integral form. Exact series solution is obtained without having to calculate series coefficients by recurrence relation.Both homogeneous and inhomog

Emilio Ignesti, Stefano Cavalieri, Lorenzo Fini, Emiliano Sali

In this letter we report the first experimental observation of temporal delay control of large-spectral-bandwidth multimode laser pulses by means of electromagnetically induced transparency (EIT). We achieved controllable retardation with limited temporal distortion of optical pulses with an input spectral bandwidth of 3.3 GHz. The experimental results compa

Radoslaw Maj, Stanislaw Mrowczynski

The Bowler-Sinyukov method to eliminate Coulomb interaction from a two-particle correlation function is discussed and tested.

A. Deltuva

The calculations of three-body direct nuclear reactions with nonlocal optical potentials are performed for the first time using the framework of Faddeev-type scattering equations. Important nonlocality effect is found for transfer reactions like d+16O -> p + 17O often improving the description of the experimental data.

D. W. Horsell, A. K. Savchenko, F. V. Tikhonenko, K. Kechedzhi

We study fluctuations of the conductance of micron-sized graphene devices as a function of the Fermi energy and magnetic field. The fluctuations are studied in combination with analysis of weak localization which is determined by the same scattering mechanisms. It is shown that the variance of conductance fluctuations depends not only on inelastic scattering

L. Deharveng, A. Zavagno, F. Schuller, J. Caplan

We take advantage of the very simple morphology of RCW 120 -- a perfect bubble -- to understand the mechanisms triggering star formation around an HII region and to establish what kind of stars are formed there. We present 870 microns observations of RCW 120, obtained with the APEX-LABOCA camera. These show the distribution of cold dust, and thus of neutral

Lisa Brouwers, Martin Camitz, Baki Cakici, Kalle Mäkilä

This article presents a unique, large-scale and spatially explicit microsimulation model that uses official anonymized register data collected from all individuals living in Sweden. Individuals are connected to households and workplaces and represent crucial links in the Swedish social contact network. This enables significant policy experiments in the domai

Rolf Schumann

In the preprint cond-mat/0701060 we detected a factor two error in the coding of the Heisenberg term of the Hamiltonian. In the result the exchange term used in the paper was that of an anisotropic Heisenberg model with $J_x=J_y=J$ and $J_z=J/2$. Thus all results given for which J=0 was chosen, remain unchanged, whereas all results containing the exchange pa

Régis Alenda, Nicola Olivetti, Camilla Schwind

We study the logic of comparative concept similarity $\CSL$ introduced by Sheremet, Tishkovsky, Wolter and Zakharyaschev to capture a form of qualitative similarity comparison. In this logic we can formulate assertions of the form " objects A are more similar to B than to C". The semantics of this logic is defined by structures equipped by distance f

A. Klotz, M. Boer, J. L. Atteia, B. Gendre

The TAROT telescopes (Telescopes a Action Rapide pour les Objets Transitoires) are two robotic observatories designed to observe the prompt optical emission counterpart and the early afterglow of gamma ray bursts (GRBs). We present data acquired between 2001 and 2008 and discuss the properties of the optical emission of GRBs, noting various interesting resul

Thomas Vogel, Thomas Neuhaus, Michael Bachmann, Wolfhard Janke

By means of sophisticated Monte Carlo methods, we investigate the conformational phase diagram of a simple model for flexible polymers with explicit thickness. The thickness constraint, which is introduced geometrically via the global radius of curvature of a polymer conformation, accounts for the excluded volume of the polymer and induces cooperative effect

Marco Roncadelli, Alessandro De Angelis, Oriana Mansutti

An anomalously large transparency of the Universe to gamma rays has recently been discovered by the Imaging Atmospheric Cherenkov Telescopes (IACTs) H.E.S.S. and MAGIC. We show that observations can be reconciled with standard blazar emission models provided photon oscillations into a very light Axion-Like Particle occur in extragalactic magnetic fields. A q

Mohammed Lemou, Florian Mehats, Pierre Raphael

We consider the three dimensional gravitational Vlasov-Poisson (GVP) system in both classical and relativistic cases. The classical problem is subcritical in the natural energy space and the stability of a large class of ground states has been derived by various authors. The relativistic problem is critical and displays finite time blow up solutions. Using s

P. Gualtieri, F. Picano, C. M. Casciola

Recently, clustering of inertial particles in turbulence has been thoroughly analyzed for statistically homogeneous isotropic flows. Phenomenologically, spatial homogeneity of particles configurations is broken by the advection of a range of eddies determined by the Stokes relaxation time of the particles which results in a multi-scale distribution of local

Guillaume Duval, Andrzej J. Maciejewski

In this paper, we consider the natural complex Hamiltonian systems with homogeneous potential $V(q)$, $q\in\C^n$, of degree $k\in\Z^\star$. The known results of Morales and Ramis give necessary conditions for the complete integrability of such systems. These conditions are expressed in terms of the eigenvalues of the Hessian matrix $V"(c)$ calculated at

Ariel Amir, Yoav Lahini, Hagai B. Perets

We study the spreading of a quantum-mechanical wavepacket in a one-dimensional tight-binding model with a noisy potential, and analyze the emergence of classical diffusion from the quantum dynamics due to decoherence. We consider a finite correlation time of the noisy environment, and treat the system by utilizing the separation of fast (dephasing) and slow

A. A. Kapustin, A. A. Shashkin, V. T. Dolgopolov, M. Goiran

We find that the polarization field, B_chi, obtained by scaling the weak-parallel-field magnetoresistance at different electron densities in a dilute two-dimensional electron system in (111) silicon, corresponds to the spin susceptibility that grows strongly at low densities. The polarization field, B_sat, determined by resistance saturation, turns out to de

Sanda N. Socoll, A. D. Barbour

The paper is concerned with the equilibrium distribution $Π_n$ of the $n$-th element in a sequence of continuous-time density dependent Markov processes on the integers. Under a $(2+\a)$-th moment condition on the jump distributions, we establish a bound of order $O(n^{-(\a+1)/2}\sqrt{\log n})$ on the difference between the point probabilities of $Π_n$ and t

Dariusz Chruscinski, Andrzej Kossakowski

We provide a new class of positive maps in matrix algebras. The construction is based on the family of balls living in the space of density matrices of n-level quantum system. This class generalizes the celebrated Choi map and provide a wide family of entanglement witnesses which define a basic tool for analyzing quantum entanglement.

Sanda N. Socoll, A. D. Barbour

The paper is concerned with the equilibrium distributions of continuous-time density dependent Markov processes on the integers. These distributions are known typically to be approximately normal, and the approximation error, as measured in Kolmogorov distance, is of the smallest order that is compatible with their having integer support. Here, an approximat

Huy-Viet Nguyen, Stefano de Gironcoli

A simple and computationally efficient scheme to calculate approximate imaginary-frequency dependent polarizability, hence asymptotic van der Waals coefficient, within density functional theory is proposed. The dynamical dipolar polarizabilities of atoms and molecules are calculated starting from the Thomas-Fermi-von Weizsäcker (TFvW) approximation for the i

D. Petrosyan, G. Bensky, G. Kurizki, I. Mazets

We examine the possibility of coherent, reversible information transfer between solid-state superconducting qubits and ensembles of ultra-cold atoms. Strong coupling between these systems is mediated by a microwave transmission line resonator that interacts near-resonantly with the atoms via their optically excited Rydberg states. The solid-state qubits can

A. D. Barbour

The paper concerns the classical occupancy scheme with infinitely many boxes. We establish approximations to the distributions of the number of occupied boxes, and of the number of boxes containing exactly r balls, within the family of translated Poisson distributions. These are shown to be of ideal asymptotic order, with respect both to total variation dist

Xiao-Wu Chen

We give a short proof to the following tilting theorem by Happel, Reiten and Smal{\o} via an explicit construction: given two abelian categories $\mathcal{A}$ and $\mathcal{B}$ such that $\mathcal{B}$ is tilted from $\mathcal{A}$, then $\mathcal{A}$ and $\mathcal{B}$ are derived equivalent.

Anna S. Molinari, Helena Alves, Zhihua Chen, Antonio Facchetti

We have investigated the electron mobility on field-effect transistors based on PDIF-CN$_{2}$ single crystals. The family of the small molecules PDI8-CN$_{2}$ has been chosen for the promising results obtained for vapour-deposited thin film FETs. We used as gate dielectric a layer of PMMA (spinned on top of the SiO$_{2}$), to reduce the possibility of electr

I. Kraus, J. Cleymans, H. Oeschler, K. Redlich

Particle production in p+p and central Pb+Pb collisions at LHC is discussed in the context of the statistical thermal model. For heavy-ion collisions, predictions of various particle ratios are presented. The sensitivity of several ratios on the temperature and the baryon chemical potential is studied in detail, and some of them, which are particularly appro

Ruth Durrer, Marcus Ruser, Marc Vonlanthen, Peter Wittwer

If our Universe is a 3+1 brane in a warped 4+1 dimensional bulk so that its expansion can be understood as the motion of the brane in the bulk, the time dependence of the boundary conditions for arbitrary bulk fields can lead to particle creation via the dynamical Casimir effect. In this talk I report results for the simplest such scenario, when the only par

Symeon Papadopoulos, Andre Skusa, Athena Vakali, Yiannis Kompatsiaris

The increasing importance of Web 2.0 applications during the last years has created significant interest in tools for analyzing and describing collective user activities and emerging phenomena within the Web. Network structures have been widely employed in this context for modeling users, web resources and relations between them. However, the amount of data

Qi-Ren Zhang

We consider the statistical irreversibility and its compatibility with the reversible dynamics. The role played by the observation is analyzed in detail. It makes our previous proof for the second law of thermodynamics clearer. On this basis, we emphasize the importance and wide applicability for the second law of thermodynamics. A new form of physics with t

Moritz Hoesch, Alexey Bosak, Dmitry Chernyshov, Helmuth Berger

A strong Kohn anomaly in ZrTe_3 is identified in the mostly transverse acoustic phonon branch along the modulation vector q_P with polarization along the a* direction. This soft mode freezes to zero frequency at the transition temperature T_P and the temperature dependence of the frequency is strongly affected by fluctuation effects. Diffuse x-ray scattering

H. Oeschler

The production of K+ and K- mesons below and at the NN threshold is summarized, based on a comparison of data with transport model calculations. K+ mesons are created in associate production together with hyperons (e.g. Lambda) in multi-step processes involving Delta resonances. These processes occur mainly during the high-density phase of the collision and

Chao Wang, Song He, Mei Huang, Qi-Shu Yan

We investigate light scalar mesons and glueballs in the $Dp-Dq$ hard-wall models, including $D3-Dq$, $D4-Dq$, and $D6-Dq$ systems. It is found that only in the $D4-D6$ and $D4-D8$ hard wall models, the predicted masses of the ${\bar q} q$ scalar meson $f_0$, scalar glueball are consistent with their experimental or lattice results. This indicates that $D4-D6

Raffaella Morganti, Bjorn Emonts, Tom Oosterloo

We report the discovery of extremely broad 21-cm HI absorption (FWZI ~1600 km/s) detected with the Westerbork Synthesis Radio Telescope in the radio source 4C37.11 (B2 0402+379). This object has been claimed to host a super-massive binary black hole (Rodriguez et al. 2006). The main features in the absorption profile are two components, separated by ~1100 km

Kenji Tsuboi

For certain compact complex Fano manifolds $M$ with reductive Lie algebras of holomorphic vector fields, we determine the analytic subvariety of the second cohomology group of $M$ consisting of Kähler classes whose Bando-Calabi-Futaki character vanishes. Then a Kähler class contains a Kähler metric of constant scalar curvature if and only if the Kähler class

Meng-Bo Luo, Xiao Hu, Valerii Vinokur

We simulated the creep motions of flux lines subject to randomly distributed point-like pinning centers. It is found that at low temperatures, the pinning barrier $U$ defined in the Arrhenius-type $v-F$ characteristics increases with decreasing force $U(F) \propto F^{-μ}$, as predicted by previous theories. The exponent $μ$ is evaluated as $0.28\pm 0.02 $ fo

Harold Auradou, Alejandro Boschan, Ricardo Chertcoff, Maria Veronica D'Angelo

Miscible tracer dispersion measurements in transparent model fractures with different types of wall roughness are reported. The nature (Fickian or not) of dispersion is determined by studying variations of the mixing front as a function of the traveled distance but also as a function of the lateral scale over which the tracer concentration is averaged. The d

Satoshi Ohya, Makoto Sakamoto

We study a particle propagation on a circle in the presence of a point interaction. We show that the one-particle Feynman kernel can be written into the sum of reflected and transmitted trajectories which are weighted by the elements of the n-th power of the scattering matrix evaluated on a line with a point interaction. As a by-product we find three-paramet

Piotr M. Kowalski, Bernd Meyer, Dominik Marx

A comprehensive phase diagram of lowest-energy structures and compositions of the rutile TiO_2(110) surface in equilibrium with a surrounding gas phase at finite temperatures and pressures has been determined using density functional theory in combination with a thermodynamic formalism. The exchange of oxygen, hydrogen, and water molecules with the gas phase

Niall Emmart, Charles C. Weems, Yang Chen

This paper presents a parallel algorithm for finding the smallest eigenvalue of a particular form of ill-conditioned Hankel matrix, which requires the use of extremely high precision arithmetic. Surprisingly, we find that commonly-used approaches that are designed for high efficiency are actually less efficient than a direct approach under these conditions.

Pedro Pablo Perez Velasco, Juan de Lara

Graph transformation is concerned with the manipulation of graphs by means of rules. Graph grammars have been traditionally studied using techniques from category theory. In previous works, we introduced Matrix Graph Grammars (MGGs) as a purely algebraic approach for the study of graph grammars and graph dynamics, based on the representation of graphs by mea

J. -P. Tignol, A. R. Wadsworth

Let A be a central simple algebra with involution sigma of first or second kind. Let v be a valuation on the sigma-fixed part F of Z(A). A sigma-special v-gauge g on A is a kind of value function on A extending v on F, such that g(sigma(x) x) = 2g(x) for all x in A. It is shown (under certain restrictions if the residue characteristic is 2) that if v is Hens

F. N. M. Al-Showaikh, N. Metwally, M. Abdel-Aty

We classify different classes of entangled states arise in a two-qubit system. Some of these classes are of Bell's state types, while others are of the Werner's state types. The degree of entanglement is quantified for different values of the atomic and the cavity parameters. We show that it is possible to generate entangled state with high degree of

C. G. Bailey, D. W. Gull, J. S. Oliveira

In this paper we derive and present an application of hypergraphic oriented matroids for the purpose of enumerating the variable interdependencies that define the chemical complexes associated with the kinetics of non-linear dynamical system representations of chemical kinetic reaction flow networks. The derivation of a hypergraphic oriented matroid is obtai

Ross P. Church, Christopher A. Tout, Jarrod R. Hurley

An N-body code containing live stellar evolution through combination of the software packages NBODY6 and STARS is presented. Operational details of the two codes are outlined and the changes that have been made to combine them discussed. We have computed the evolution of clusters of 10 000 stars using the combined code and we compare the results with those o

Ehud Hrushovski, David Kazhdan

We develop a "motivic integration" version of the Poisson summation formula for function fields, with values in the Grothendieck ring of definable exponential sums. We also study division algebras over the function field, and obtain relations among the motivic Fourier transforms of a test function at different completions. We use these to prove, in a

D. F. Agterberg, M. Sigrist, H. Tsunetsugu

Recently, it has been reported that the low-temperature high-magnetic field phase in CeCoIn5 (Q-phase), has spin-density wave (SDW) order that only exists within this phase. This indicates that the SDW order is the result of the development of pair density wave (PDW) order in the superconducting phase that coexists with d-wave superconductivity. Here we deve

Ehud Hrushovski

We study finite imaginaries in certain valued fields, and prove a conjecture of Cluckers and Denef.

Ying Li, Constantine Yannouleas, Uzi Landman

Energy spectra, spin configurations, and entanglement characteristics of a system of four electrons in lateral double quantum dots are investigated using exact diagonalization (EXD), as a function of interdot separation, applied magnetic field, and strength of interelectron repulsion. A distinctly different quantum behavior is found compared to that of circu

Dillon Mayhew, Gordon Royle, Geoff Whittle

We give a characterization of the internally 4-connected binary matroids that have no minor isomorphic to M(K3,3). Any such matroid is either cographic, or is isomorphic to a particular single-element extension of the bond matroid of a cubic or quartic Mobius ladder, or is isomorphic to one of eighteen sporadic matroids.

R. N. Mohapatra

The discovery of neutrino masses has provided strong hints in favor of the possibility that B-L symmetry is an intimate feature of physics beyond the standard model. I discuss how important information about this symmetry as well as other scenarios for TeV scale new physics can be obtained from the baryon number violating process, neutron-anti-neutron oscill

Francesca Sammarruca

We predict the energy per baryon in nuclear matter with non-zero fraction of $Λ$ hyperons. We include Dirac effects on the nucleons as well as the $Λ$ and describe how the latter is implemented. We use the nucleon-hyperon meson-exchange potentials from the Juelich group, the latest as well as an earlier version. The dependence of the results on the many-body

Yanqiu Li, Qian Miao, Arto Nurmikko, Humphrey Maris

A detailed analysis of the use of an optical cavity to enhance picosecond ultrasonic signals is presented. The optical cavity is formed between a distributed Bragg reflector (DBR) and the metal thin film samples to be studied. Experimental results for Al and Cu films show enhancement of acoustic signals by up to two orders of magnitude and are in good agreem

M. Bestvina, K. Bromberg, K. Fujiwara, J. Souto

We prove that there are Fenchel-Nielsen coordinates for the Teichmueller space of a finite area hyperbolic surface with respect to which the length functions are convex.

Xiaolin Qin, Yong Feng, Jingwei Chen, Jingzhong Zhang

We present a new algorithm for reconstructing an exact algebraic number from its approximate value using an improved parameterized integer relation construction method. Our result is consistent with the existence of error controlling on obtaining an exact rational number from its approximation. The algorithm is applicable for finding exact minimal polynomial

M. J. Harvey, G. Giupponi, G. De Fabritiis

The high arithmetic performance and intrinsic parallelism of recent graphical processing units (GPUs) can offer a technological edge for molecular dynamics simulations. ACEMD is a production-class bio-molecular dynamics (MD) simulation program designed specifically for GPUs which is able to achieve supercomputing scale performance of 40 nanoseconds/day for a

Michael Levin, Matthew P. A. Fisher

Using the parton construction, we build a three-dimensional (3D) multilayer fractional quantum Hall state with average filling ν= 1/3 per layer that is qualitatively distinct from a stacking of weakly coupled Laughlin states. The state supports gapped charge e/3 fermionic quasiparticles that can propagate both within and between the layers, in contrast to th

Craig A. Tracy, Harold Widom

A limit theorem for the total current in the asymmetric simple exclusion process (ASEP) with step initial condition is proved. This extends the result of Johansson on TASEP to ASEP.

Aniruddha Konar, Tian Fang, Debdeep Jena

The effect of various dielectrics on charge mobility in single layer graphene is investigated. By calculating the remote optical phonon scattering arising from the polar substrates, and combining it with their effect on Coulombic impurity scattering, a comprehensive picture of the effect of dielectrics on charge transport in graphene emerges. It is found tha

U. Rau, S. Bhatnagar, M. A. Voronkov, T. J. Cornwell

This paper summarizes some of the major calibration and image reconstruction techniques used in radio interferometry and describes them in a common mathematical framework. The use of this framework has a number of benefits, ranging from clarification of the fundamentals, use of standard numerical optimization techniques, and generalization or specialization

Dong Li, Xiaoyi Zhang

For the focusing mass-critical NLS $iu_t+Δu=-|u|^{\frac 4d}u$, it is conjectured that the only global non-scattering solution with ground state mass must be a solitary wave up to symmetries of the equation. In this paper, we settle the conjecture for $H^1_x$ initial data in dimensions $d=2,3$ with spherical symmetry and $d\ge 4$ with certain splitting-spheri

Ping V. Lin, F. E. Camino, V. J. Goldman

An apparent h/fe Aharonov-Bohm flux period, where f is an integer, has been reported in coherent quantum Hall devices. Such sub-period is not expected for non-interacting electrons and thus is thought to result from interelectron Coulomb interaction. Here we report experiments in a Fabry-Perot interferometer comprised of two wide constrictions enclosing an e

M. Mastnak, J. Pevtsova, P. Schauenburg, S. Witherspoon

We prove finite generation of the cohomology ring of any finite dimensional pointed Hopf algebra, having abelian group of grouplike elements, under some mild restrictions on the group order. The proof uses the recent classification by Andruskiewitsch and Schneider of such Hopf algebras. Examples include all of Lusztig's small quantum groups, whose cohomo

Michael Heusener, Richard Weidmann

We study Nielsen equivalence classes of generating pairs of Kleinian groups and HNN-extensions. We establish the following facts: - Hyperbolic 2-bridge knot groups have infinitely many Nielsen classes of generating pairs. - For any natural number N there is a closed hyperbolic 3-manifold whose fundamental group has N distinct Nielsen classes of generating pa

Martin E. Pessah, Jeremy Goodman

We investigate the stability of incompressible, exact, non-ideal magnetorotational (MRI) modes against parasitic instabilities. Both Kelvin-Helmholtz and tearing-mode parasitic instabilities may occur in the dissipative regimes accessible to current numerical simulations. We suppose that a primary MRI mode saturates at an amplitude such that its fastest para

G. Ghisellini, F. Tavecchio

The jets of powerful blazars propagate within regions relatively dense of radiation produced externally to the jet. This radiation is a key ingredient to understand the origin of the high energy emission of blazars, from the X-ray to the gamma-ray energy band. These external radiation fields control the amount of the inverse Compton radiation with respect to

Neil Barnaby, Zhiqi Huang, Lev Kofman, Dmitry Pogosyan

We propose a qualitatively new mechanism for generating cosmological fluctuations from inflation. The non-equilibrium excitation of interacting scalar fields often evolves into infra-red (IR) and ultra-violet (UV) cascading, resulting in an intermediate scaling regime. We observe elements of this phenomenon in a simple model with inflaton ϕand iso-inflaton χ

Mihály Weiner

A collection of pairwise mutually unbiased bases (in short: MUB) in d>1 dimensions may consist of at most d+1 bases. Such "complete" collections are known to exists in C^d when d is a power of a prime. However, in general little is known about the maximal number N(d) of bases that a collection of MUBs in C^d can have. In this work it is proved that a

Alessandra Buonanno, Yi Pan, Harald P. Pfeiffer, Mark A. Scheel

We calibrate the effective-one-body (EOB) model to an accurate numerical simulation of an equal-mass, non-spinning binary black-hole coalescence produced by the Caltech-Cornell collaboration. Aligning the EOB and numerical waveforms at low frequency over a time interval of ~1000M, and taking into account the uncertainties in the numerical simulation, we inve

Richard J. Mathar

The slowly converging series sum_{k=3}^infinity 1/[k * log k * (log log k)^a] is evaluated to 38.4067680928 at a=2. After some initial terms, the infinite tail of the sum is replaced by the integral of the associated interpolating function, which is available in simple analytic form. Biases that originate from the difference between the smooth area under the

Oleg N. Kirillov

We consider an axi-symmetric rotor perturbed by dissipative, conservative, and non-conservative positional forces originated at the contact with the anisotropic stator. The Campbell diagram of the unperturbed system is a mesh-like structure in the frequency-speed plane with double eigenfrequencies at the nodes. The diagram is convenient for the analysis of t

Katia Jaffrès-Runser, Cristina Comaniciu, Jean-Marie Gorce

Wireless ad hoc networks are seldom characterized by one single performance metric, yet the current literature lacks a flexible framework to assist in characterizing the design tradeoffs in such networks. In this work, we address this problem by proposing a new modeling framework for routing in ad hoc networks, which used in conjunction with metaheuristic mu

V. Guzey, A. W. Thomas, K. Tsushima

We estimate the nuclear medium modifications of the quark contribution to the bound nucleon spin sum rule, J^{q*}, as well as the separate helicity, ΔΣ*, and the angular momentum, L^{q*}, contributions to J^{q*}. For the calculation of the bound nucleon generalized parton distributions (GPDs), we use as input the bound nucleon elastic form factors predicted

Mark Gross, Rahul Pandharipande, Bernd Siebert

Elements of the tropical vertex group, introduced by Kontsevich and Soibelman, are formal families of symplectomorphisms of the 2-dimensional algebraic torus. We prove ordered product factorizations in the tropical vertex group are equivalent to calculations of certain genus 0 relative Gromov-Witten invariants of toric surfaces. The relative invariants which

Mark Friesen, S. N. Coppersmith

Electron states are studied for quantum dots in a strained Si quantum well, taking into account both valley and orbital physics. Realistic geometries are considered, including circular and elliptical dot shapes, parallel and perpendicular magnetic fields, and (most importantly for valley coupling) the small local tilt of the quantum well interface away from

Kazuya Koyama, Atsushi Taruya, Takashi Hiramatsu

We present a formalism to calculate the non-linear matter power spectrum in modified gravity models that explain the late-time acceleration of the Universe without dark energy. Any successful modified gravity models should contain a mechanism to recover General Relativity (GR) on small scales in order to avoid the stringent constrains on deviations from GR a

V. Bashiry, M. Bayar, K. Azizi

In this paper, we compare the branching ratio and rate difference of electron channel to muon channel of $B \rar K_0^\ast (1430) \ell^+ \ell^-$ and $B \rar K^\ast \ell^+ \ell^-$decays, where $K_0^\ast (1430)$ is the p--wave scalar meson, in the supersymmetric models. MSSM with $R$ parity is considered since considerable deviation from the standard model pred

J. P. Pridham

We define and construct mixed Hodge structures on real schematic homotopy types of complex projective varieties, giving mixed Hodge structures on their homotopy groups and pro-algebraic fundamental groups. We also show that these split on tensoring with the ring R[x] equipped with the Hodge filtration given by powers of (x-i), giving new results even for sim