June 2007 arXiv papers — page 25
Showing 2,401–2,500 of 4,521 papers
Yanhua Shih
One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. In an entangled EPR two-particle system, the value of the momentum (position) for neither single subsystem is determined. However, if one of the subsystems is measured to have a certain momentum (position), the other subsystem is determined to h
Aditi Sen De, Ujjwal Sen, Jacek Dziarmaga, Anna Sanpera
We study frustrated quantum systems from a quantum information perspective. Within this approach, we find that highly frustrated systems do not follow any general ''area law'' of block entanglement, while weakly frustrated ones have area laws similar to those of nonfrustrated systems away from criticality. To calculate the block entanglement
Pion freeze-out as seen through HBT correlations in heavy ion collisions from FAIR/AGS to RHIC energies
nucl-thQingfeng Li, Marcus Bleicher, Horst Stoecker
We perform a systematic analysis of several HBT parameters in heavy ion collisions from $E_{\rm beam}=2$ AGeV to $\sqrt {s_{\rm NN}}=200$ GeV within the UrQMD transport approach and compare the results to experimental data where available. We find that the 'lifetime' of the emission source as calculated from $τ\sim \sqrt{R_O^{2}-R_S^{2}}$, is larger
Laplacian instability of planar streamer ionization fronts - an example of pulled front analysis
nlin.PSGianne Derks, Ute Ebert, Bernard Meulenbroek
Streamer ionization fronts are pulled fronts propagating into a linearly unstable state; the spatial decay of the initial condition of a planar front selects dynamically one specific long time attractor out of a continuous family. A transverse stability analysis has to take these features into account. In this paper we introduce a framework for this transver
B. Militello, K. Yuasa, H. Nakazato, A. Messina
A quantum system put in interaction with another one that is repeatedly measured is subject to a non-unitary dynamics, through which it is possible to extract subspaces. This key idea has been exploited to propose schemes aimed at the generation of pure quantum states (purification). All such schemes have so far been considered in the ideal situations of iso
A. Halbritter, P. Makk, Sz. Csonka, G. Mihaly
Experimental results showing huge negative differential conductance in gold-hydrogen molecular nanojunctions are presented. The results are analyzed in terms of two-level system (TLS) models: it is shown that a simple TLS model cannot produce peaklike structures in the differential conductance curves, whereas an asymmetrically coupled TLS model gives perfect
Klaus Aehlig
Model checking properties are often described by means of finite automata. Any particular such automaton divides the set of infinite trees into finitely many classes, according to which state has an infinite run. Building the full type hierarchy upon this interpretation of the base type gives a finite semantics for simply-typed lambda-trees. A calculus based
Analysis on Heavy Quarkonia Transitions with Pion Emission in Terms of the QCD Multipole Expansion and Determination of Mass Spectra of Hybrids
hep-phHong-Wei Ke, Jian Tang, Xi-Qing Hao, Xue-Qian Li
One of the most important tasks in high energy physics is search for the exotic states, such as glueball, hybrid and multi-quark states. The transitions $ψ(ns)\to ψ(ms)+ππ$ and $Υ(ns)\to Υ(ms)+ππ$ attract great attentions because they may reveal characteristics of hybrids. In this work, we analyze those transition modes in terms of the theoretical framework
Kfir Blum, Yosef Nir, Eli Waxman
Measurements of flavor ratios of astrophysical neutrino fluxes are sensitive to the two yet unknown mixing parameters $θ_{13}$ and $δ$ through the combination $\sinθ_{13}\cosδ$. We extend previous studies by considering the possibility that neutrino fluxes from more than a single type of sources will be measured. We point out that, if reactor experiments est
Laurent Bessières, Gérard Besson, Michel Boileau, Sylvain Maillot
Let M be a closed, orientable, irreducible, non-simply connected 3-manifold. We prove that if M admits a sequence of Riemannian metrics whose sectional curvature is locally controlled and whose thick part becomes asymptotically hyperbolic and has a sufficiently small volume, then M is Seifert fibred or contains an incompressible torus. This result gives an a
BRIDGE: A Direct-tree Hybrid N-body Algorithm for Fully Self-consistent Simulations of Star Clusters and their Parent Galaxies
astro-phM. Fujii, M. Iwasawa, Y. Funato, J. Makino
We developed a new direct-tree hybrid N-body algorithm for fully self-consistent N-body simulations of star clusters in their parent galaxies. In such simulations, star clusters need high accuracy, while galaxies need a fast scheme because of the large number of the particles required to model it. In our new algorithm, the internal motion of the star cluster
Ulrich Haisch
We present a concise review of the recent theoretical progress concerning the standard model calculation of the inclusive radiative Bbar -> X_s gamma decay. Particular attention is thereby devoted to the calculations of the next-to-next-to-leading order fixed-order O(alpha_s^2) contributions, non-local O(alpha_s Lambda/m_b) power corrections, and logarithmic
Ethan Cotterill
We study linear series on a general curve of genus $g$, whose images are exceptional with regard to their secant planes. Working in the framework of an extension of Brill-Noether theory to pairs of linear series, we prove that a general curve has no linear series with exceptional secant planes, in a very precise sense, whenever the total number of series is
Measurement of Branching Fraction and Time-Dependent CP Asymmetry Parameters in B0 -> D*+ D*- Ks Decays
hep-exJ. Dalseno
We present a measurement of the branching fraction and time-dependent CP violation parameters for B0 -> D*+ D*- Ks decays. We also obtain an upper limit on the product branching fraction for the possible two-body decay, B0 -> Ds1+(2536) D*-. These results are obtained from a 414 fb-1 data sample that contains 449e10^6 BBbar pairs collected at the Upsilon(4S)
Young-Eun Choi, Kasra Rafi, Caroline Series
We continue the comparison between lines of minima and Teichmueller geodesics begun in [CRS1]. We show that in the Teichmueller space of a surface S, lines of minima are quasi-geodesic with respect to the Teichmueller metric. The quasi-geodesic constants depend only on the topological type of S.
Hyojoong Kim, Kyung Kiu Kim, Nakwoo Kim
In this paper we generalize the work of Lin, Lunin and Maldacena on the classification of 1/2-BPS M-theory solutions to a specific class of 1/4-BPS configurations. We are interested in the solutions of 11 dimensional supergravity with $SO(3)\times SO(4)$ symmetry, and it is shown that such solutions are constructed over a one-parameter familiy of 4 dimension
Alexei A. Starobinsky
For higher-derivative f(R) gravity where R is the Ricci scalar, a class of models is proposed which produce viable cosmology different from the LambdaCDM one at recent times and satisfy cosmological, Solar system and laboratory tests. These models have both flat and de Sitter space-times as particular solutions in the absence of matter. Thus, a cosmological
Yi Ni
Given a closed 3--manifold $Y$, we show that the Heegaard Floer homology determines whether $Y$ fibres over the circle with a fibre of negative Euler characteristic. This is an analogue of an earlier result about knots proved by Ghiggini and the author.
Li Ma, Anqiang Zhu
Given a Riemannian submersion, we study the relation between lambda constants introduced by G.Perelman on the base manifold and the total space of a Riemannian submersion. We also discuss the relationship between the first eigenvalues of Laplacians on the base manifold and that of the total space. The quantities on warped products are discussed in detail.
Eben Kenah, Marc Lipsitch, James M. Robins
The generation interval is the time between the infection time of an infected person and the infection time of his or her infector. Probability density functions for generation intervals have been an important input for epidemic models and epidemic data analysis. In this paper, we specify a general stochastic SIR epidemic model and prove that the mean genera
Sergio Boixo, Alex Monras
We introduce an operational interpretation for pure-state global multipartite entanglement based on quantum estimation. We show that the estimation of the strength of low-noise locally depolarizing channels, as quantified by the regularized quantum Fisher information, is directly related to the Meyer-Wallach multipartite entanglement measure. Using channels
Evgeny I. Buchbinder
In this note, we propose that the infrared structure of gluon amplitudes at strong coupling can be fully extracted from a local consideration near cusps. This is consistent with field theory and correctly reproduces the infrared divergences of the four-gluon amplitude at strong coupling calculated recently by Alday and Maldacena.
J. Swift, Wm. J. Welch
This article synthesizes observational data from an extensive program aimed toward a comprehensive understanding of star formation in a low-mass star-forming molecular cloud. New observations and published data spanning from the centimeter wave band to the near infrared reveal the high and low density molecular gas, dust, and pre-main sequence stars in L1551
G. Toledo Sanchez, J. L. Garcia-Luna, V. Gonzalez-Enciso
We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0 -> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are driven by the mass and width parameters of the sigma(600), and the usually neglected contribution of the a_1(1260), although small by itself, may become sizable through its interference with pion bremsstrah
Nicolae Manolache
We characterize the Gorenstein nilpotent scheme structures on a smooth algebraic variety as support, in terms of a duality property of the graded objects associated to two canonical filtrations.
Graeme W. Milton
Metamaterials are constructed such that, for a narrow range of frequencies, the momentum density depends on the local displacement gradient, and the stress depends on the local velocity. In these models the momentum density generally depends not only on the strain, but also on the local rotation, and the stress is generally not symmetric. A variant is constr
Shih-Chieh Hsu
We report searches for standard model (SM) Higgs production decaying to WW(*) and continuum ZZ production in the two charged lepton and two neutrino final states. The data were collected with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 1.1^fb-1. In order to separate the processes contributing to the final state,
J. M. Rondinelli, M. Stengel, N. A. Spaldin
While tremendous success has been achieved to date in creating both single phase and composite magnetoelectric materials, the quintessential electric-field control of magnetism remains elusive. In this work, we demonstrate a linear magnetoelectric effect which arises from a novel carrier-mediated mechanism, and is a universal feature of the interface between
Mark L. Henle, R. McGorty, A. D. Dinsmore, Alex J. Levine
We study the mobility of extended objects (rods) on a spherical liquid-liquid interface to show how this quantity is modified in a striking manner by both the curvature and the topology of the interface. We present theoretical calculations and experimental measurements of the interfacial fluid velocity field around a moving rod bound to the crowded interface
G. F. Rubilar
We formulate a general framework for describing the electromagnetic properties of spacetime. These properties are encoded in the `constitutive tensor of the vacuum', a quantity analogous to that used in the description of material media. We give a generally covariant derivation of the Fresnel equation describing the local properties of the propagation of
Igor Zutic, Jaroslav Fabian, Steven C. Erwin
An impressive success of spintronic applications has been typically realized in metal-based structures which utilize magnetoresistive effects for substantial improvements in the performance of computer hard drives and magnetic random access memories. Correspondingly, the theoretical understanding of spin-polarized transport is usually limited to a metallic r
B. Nord, R. Stanek, E. Rasia, A. E. Evrard
We explore how the behavior of galaxy cluster scaling relations are affected by flux-limited selection biases and intrinsic covariance among observable properties. Our models presume log-normal covariance between luminosity (L) and temperature (T) at fixed mass (M), centered on evolving, power-law mean relations as a function of host halo mass. Selection can
Jorgen Ellegaard Andersen
We prove that the mapping class group of a closed oriented surface of genus at least two does not have Kazhdan's property (T).
Alexander Bolonkin
There are two main methods of nulcear fusion: inertial confinement fusion (ICF) and magnetic confinement fusion (MCF). Existing thermonuclear reactors are very complex, expensive, large, and heavy. They cannot achieve the Lawson creterion. The author offers an innovation. ICF has on the inside surface of the shell-shaped combustion chamber a covering of smal
Graciela B Gelmini, Oleg Kalashev, Dmitry V. Semikoz
We calculate the flux of "GZK-photons", namely the flux of photons produced by extragalactic nucleons through the resonant photoproduction of pions, the so called GZK effect. This flux depends on the UHECR spectrum on Earth, of the spectrum of nucleons emitted at the sources, which we characterize by its slope and maximum energy, on the distribution
C. Sulkowski, T. Klimczuk, R. J. Cava, K. Rogacki
The intermetallic perovskite MgCNi3 is a superconductor with a Tc=7 K. Substitution of Fe and Ru for Ni decreases Tc monotonically as the doping concentration is increased. Here we report thermopower measurements, S(T), on MgCNi3, MgCNi3-xFex and MgCNi3-xRux. For MgCNi3, the thermopower is negative, - 12.5 mikroV/K, at 300 K. The absolute value of S decrease
Backreaction in trans-Planckian cosmology: renormalization, trace anomaly and selfconsistent solutions
gr-qcDiana López Nacir, Francisco D. Mazzitelli
We analyze the semiclassical Einstein equations for quantum scalar fields satisfying modified dispersion relations. We first discuss in detail the renormalization procedure based on adiabatic subtraction and dimensional regularization. We show that, contrary to what expected from power counting arguments, in 3+1 dimensions the subtraction involves up to the
Francisco C. Alcaraz, Matheus J. Lazo
We introduce and solvev a special family of integrable interacting vertex models that generalizes the well known six-vertex model. In addition to the usual nearest-neighbor interactions among the vertices, there exist extra hard-core interactions among pair of vertices at larger distances.The associated row-to-row transfer matrices are diagonalized by using
Comments on the breakdown of the Landauer bound for information erasure in the quantum regime
quant-phElias P. Gyftopoulos, Michael R. von Spakovsky
Upon reviewing the article by Allahverdyan and Nieuwenhuizen in PRE, we conclude that neither the Landauer principle nor the counterexamples presented by the authors have any relation (i) to thermodynamics, and (ii) to the interdependence of nonstatistical quantum physics and thermodynamics.
P. Goerss, H. -W. Henn, M. Mahowald, C. Rezk
We develop a framework for displaying the stable homotopy theory of the sphere, at least after localization at the second Morava K-theory K(2). At the prime 3, we write the spectrum L_{K(2)S^0 as the inverse limit of a tower of fibrations with four layers. The successive fibers are of the form E_2^hF where F is a finite subgroup of the Morava stabilizer grou
Planets around evolved intermediate-mass stars. I. Two substellar companions in the open clusters NGC 2423 and NGC 4349
astro-phC. Lovis, M. Mayor
Context. Many efforts are being made to characterize extrasolar planetary systems and unveil the fundamental mechanisms of planet formation. An important aspect of the problem, which remains largely unknown, is to understand how the planet formation process depends on the mass of the parent star. In particular, as most planets discovered to date orbit a sola
B. Coppi
The formation of macroscopic reconnected magnetic structures (islands) have been observed in advanced experiments on weakly collisional, well confined plasmas while established theories of the drift-tearing modes, which depend strongly on the electron temperature gradient and can describe the formation of these structures, had predicted practically inaccessi
Guido Garay, Diego Mardones, Kate J. Brooks, Liza Videla
We present observations of 1.2-mm dust continuum emission, made with the Swedish ESO Submillimeter Telescope, towards eighteen luminous IRAS point sources, all with colors typical of compact HII regions and associated with CS(2-1) emission, thought to be representative of young massive star forming regions. Emission was detected toward all the IRAS objects.
J. E. Steiner, A. S. Oliveira, C. A. O. Torres, A. Damineli
Some of the luminous Compact Binary Supersoft X-Ray sources (CBSS) have shown indications of jets, also called satellites due to their appearance in the spectra. In V Sagittae (V Sge) stars, the galactic counterparts of the CBSS, such features have been reported only for WX Cen. If V Sge stars are indeed the analogs of CBSS, one may expect transient jet emis
Mu-Chun Chen
Neutrino physics has entered an era of precision measurements. With these precise measurements, we may be able to distinguish different models that have been constructed to explain the small neutrino masses and the large mixing among them. In this talk, I review some of the existing theoretical models and their predictions for neutrino oscillations.
Harald Grosse, Michael Wohlgenannt
Field theories on deformed spaces suffer from the IR/UV mxing and renormalization is generically spoiled. In work with R. Wulkenhaar, one of us realized a way to cure this desease by adding one more marginal operator. We review these ideas, show the application to $ϕ^3$ models and use heat kernel expansion methods for a scalar field theory coupled to an exte
Shu Kawaguchi, Joseph H. Silverman
Let F and G be morphisms of degree at least 2 from P^N to P^N that are defined over the algebraic closure of Q. We define the arithmetic distance d(F,G) between F and G to be the supremum over all algebraic points P of |h_F(P)-h_G(P)|, where h_F and h_G are the canonical heights associated to the morphisms F and G, respectively. We prove comparison theorems
S. B. McKagan, W. Handley, K. K. Perkins, C. E. Wieman
Physics faculty consider the photoelectric effect important, but many erroneously believe it is easy for students to understand. We have developed curriculum on this topic including an interactive computer simulation, interactive lectures with peer instruction, and conceptual and mathematical homework problems. Our curriculum addresses established student di
J Krawczyk, A L Owczarek, T Prellberg
We investigate a lattice model of polymers where the nearest-neighbour monomer-monomer interaction strengths differ according to whether the local configurations have so-called ``hydrogen-like'' formations or not. If the interaction strengths are all the same then the classical $θ$-point collapse transition occurs on lowering the temperature, and the
General Hubbard model for strongly interacting fermions in an optical lattice and its phase detection
cond-mat.otherL. -M. Duan
Based on consideration of the system symmetry and its Hilbert space, we show that strongly interacting fermions in an optical lattice or superlattice can be generically described by a lattice resonance Hamiltonian. The latter can be mapped to a general Hubbard model with particle assisted tunneling rates. We investigate the model under population imbalance a
Menachem Shlossberg
We study relatively minimal subgroups in topological groups. We find, in particular, some natural relatively minimal subgroups in unipotent groups which are defined over "good" rings. By "good" rings we mean archimedean absolute valued (not necessarily associative) division rings. Some of the classical rings which we consider besides the fiel
R. Aloisio, V. Berezinsky, A. Gazizov
We study the solution of the diffusion equation for Ultra-High Energy Cosmic Rays in the general case of an expanding universe, comparing it with the well known Syrovatsky solution obtained in the more restrictive case of a static universe. The formal comparison of the two solutions with all parameters being fixed identically reveals an appreciable discrepan
Viscous spin exchange torque on precessional magnetization in $(\mathrm{LaMnO}_3)_{2n}/(\mathrm{SrMnO}_3)_{n}$ superlattices
cond-mat.mtrl-sciH. B. Zhao, K. J. Smith, Y. Fan, G. Lüpke
Photoinduced magnetization dynamics is investigated in chemically ordered $(\mathrm{LaMnO}_3)_{2n}/(\mathrm{SrMnO}_3)_n$ superlattices using the time-resolved magneto-optic Kerr effect. A monotonic frequency-field dependence is observed for the $n=1$ superlattice, indicating a single spin population consistent with a homogeneous hole distribution. In contras
Greg Sepesi
An inherently parallel algorithm is proposed that efficiently performs selection: finding the K-th largest member of a set of N members. Selection is a common component of many more complex algorithms and therefore is a widely studied problem. Not much is new in the proposed dualheap selection algorithm: the heap data structure is from J.W.J.Williams, the bo
Pavel Etingof, Xiaoguang Ma
We attach elliptic Dunkl operators to an abelian variety with a finite group action. This generalizes elliptic Dunkl operators for Weyl groups, defined by Buchstaber, Felder, and Veselov in 1994. We show that these operators commute, and use them to define representations from category O of elliptic Cherednik algebras. We also consider the monodromy represen
N. Brosch, A. Kniazev, D. Buckley, D. O'Donoghue
We report long-slit spectroscopic observations of the dust-lane polar-ring galaxy AM1934-563 obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. The observations target the spectral region of the Ha, [NII] and [SII] emission-lines, but show also deep NaI stellar absorption lines that we interpret as produced b
A New Comment on "Experimental Observation of Optical Rotation Generated in Vacuum by a Magnetic Field"
hep-exPierre Pugnat
One of the magneto-optical properties of the mirrors of the Fabry-Perot cavity used for the experiment is considered as a possible origin of the PVLAS measurement result.
Arthur Jaffe, David Moser
We give an intuitive method--using local, cyclic replica symmetry--to isolate exponential tree decay in truncated (connected) correlations. We give an expansion and use the symmetry to show that all terms vanish, except those displaying {\em replica condensation}. The condensation property ensures exponential tree decay. We illustrate our method in a low-tem
Rajesh Sudarsan, Calvin J. Ribbens
Traditional parallel schedulers running on cluster supercomputers support only static scheduling, where the number of processors allocated to an application remains fixed throughout the execution of the job. This results in under-utilization of idle system resources thereby decreasing overall system throughput. In our research, we have developed a prototype
Alessandro Gimigliano, Brian Harbourne, Monica Idà
We study the connection between the generation of a fat point scheme supported at general points in the plane and the behaviour of the cotangent bundle with respect to some rational curves particularly relevant for the scheme. We put forward two conjectures, giving examples and partial results in support of them.
Robert J. Young, Samuel J. Dewhurst, R. Mark Stevenson, Paola Atkinson
We show storage of the circular polarisation of an optical field, transferring it to the spin-state of an individual electron confined in a single semiconductor quantum dot. The state is subsequently readout through the electronically-triggered emission of a single photon. The emitted photon shares the same polarisation as the initial pulse but has a differe
Vasily E. Tarasov
In this paper we consider a phase space path integral for general time-dependent quantum operations, not necessarily unitary. We obtain the path integral for a completely positive quantum operation satisfied Lindblad equation (quantum Markovian master equation). We consider the path integral for quantum operation with a simple infinitesimal generator.
Zhi-Qiang Jiang, Wei-Xing Zhou
Multifractal analysis and extensive statistical tests are performed upon intraday minutely data within individual trading days for four stock market indexes (including HSI, SZSC, S&P500, and NASDAQ) to check whether the indexes (instead of the returns) possess multifractality. We find that the mass exponent $τ(q)$ is linear and the singularity $α(q)$ is clos
Laura Thevenard, Audrey Miard, Laurent Vila, Giancarlo Faini
We present an original method to magnetically pattern thin layers of (Ga,Mn)As. It relies on local hydrogen passivation to significantly lower the hole density, and thereby locally suppress the carrier-mediated ferromagnetic phase. The sample surface is thus maintained continuous, and the minimal structure size is of about 200 nm. In micron-sized ferromagnet
S. Fritz, J. Wilms, K. Pottschmidt, M. A. Nowak
The Black Hole (BH) binary Cygnus X-1 has been observed simultaneously by INTEGRAL, RXTE, and XMM-Newton for four times in November and December 2004, when Cyg X-1 became first observable with XMM-Newton. During these observations the source was found in one of its transitional states between the hard state and the soft state. We obtained a high signal to no
Matthias Neubert
Using methods of effective field theory, a systematic analysis of the fragmentation functions D_{a/H}(x,m_Q) of a hadron H containing a heavy quark Q is performed (with a=Q,Q_bar,q,q_bar,g). By integrating out pair production of virtual and real heavy quarks, the fragmentation functions are matched onto a single nonperturbative function describing the fragme
Gerard Ben Arous, Anton Bovier, Jiri Cerny
We consider a version of a Glauber dynamics for a p-spin Sherrington--Kirkpatrick model of a spin glass that can be seen as a time change of simple random walk on the N-dimensional hypercube. We show that, for any p>2 and any inverse temperature β>0, there exist constants g>0, such that for all exponential time scales, $\exp(γN)$, with $γ< g$, the properly r
Rotational stacking and its electronic effects on graphene films grown on 4H-SiC$(000\bar{1})$
cond-mat.mtrl-sciJ. Hass, F. Varchon, J. E. Millan-Otoya, M. Sprinkle
We examine the stacking order of multilayer graphene grown on the SiC$(000\bar{1})$ surface using low-energy electron diffraction and surface X-ray diffraction. We show that the films contain a high density of rotational stacking faults caused by three types of rotated graphene: sheets rotated $30^\circ$ and $\pm 2.20^\circ$ relative to the SiC substrate. Th
S. Antusch, L. E. Ibanez, T. Macri
We study possible patterns of neutrino masses and mixings in string models in which Majorana neutrino masses are generated by a certain class of string theory instantons recently considered in the literature. These instantons may generate either directly the dim=5 Weinberg operator or right-handed neutrino Majorana masses, both with a certain flavour-factori
R. S. Thorne, A. Sherstnev, C. Gwenlan
We present a study of the results obtained combining LO partonic matrix elements with different orders of partons distributions. These are compared to the best prediction using NLO for both matrix elements and parton distributions. The aim is to determine which parton distributions are most appropriate to use in those cases where only LO matrix elements are
NNPDF Collaboration, J. Rojo, R. D. Ball, L. Del Debbio
We give a status report on the determination of a set of parton distributions based on neural networks. In particular, we summarize the determination of the nonsinglet quark distribution up to NNLO, we compare it with results obtained using other approaches, and we discuss its use for a determination of $α_s$.
S. Camalet R. Chitra
We study the decoherence of a spin-1/2 induced by an environment which is on the verge of a continuous phase transition. We consider spin environments described by the ferromagnetic and antiferromagnetic Heisenberg models on a square lattice. As is well known, these two dimensional systems undergo a continuous phase transition at zero temperature, where, the
Eugene Asarin, Thierry Cachat, Alexander Seliverstov, Tayssir Touili
The classical attenuation regulation of gene expression in bacteria is considered. We propose to represent the secondary RNA structure in the leader region of a gene or an operon by a term, and we give a probabilistic term rewriting system modeling the whole process of such a regulation.
E. Sola, J. Casulleras, J. Boronat
We present a diffusion Monte Carlo study of a vortex line excitation attached to the center of a $^4$He droplet at zero temperature. The vortex energy is estimated for droplets of increasing number of atoms, from N=70 up to 300 showing a monotonous increase with $N$. The evolution of the core radius and its associated energy, the core energy, is also studied
Po-Shen Loh, Benny Sudakov
Let G be a graph with maximum degree Δwhose vertex set is partitioned into parts V(G) = V_1 \cup ... \cup V_r. A transversal is a subset of V(G) containing exactly one vertex from each part V_i. If it is also an independent set, then we call it an independent transversal. The local degree of G is the maximum number of neighbors of a vertex v in a part V_i, t
Nilton Penha, Bernhard Rothenstein, Doru Paunescu
A two-dimensional Minkowski spacetime diagram is neatly represented on a Euclidean ordinary plane. However the Euclidean lengths of the lines on the diagram do not correspond to the true values of physical quantities in spacetime, except for those referring to the stationary reference frame. In order to extend its abilities to other inertial reference frames
Francesca Colaiori, Gianfranco Durin, Stefano Zapperi
In conducting ferromagnetic materials, a moving domain wall induces eddy currents in the sample which give rise to an effective retarding pressure on the domain wall. We show here that the pressure is not just proportional to the instantaneous velocity of the wall, as often assumed in domain wall models, but depends on the history of the motion. We calculate
Tuomas Hytonen, Juha-Pekka Pellonpaa, Kari Ylinen
We study decompositions of operator measures and more general sesquilinear form measures $E$ into linear combinations of positive parts, and their diagonal vector expansions. The underlying philosophy is to represent $E$ as a trace class valued measure of bounded variation on a new Hilbert space related to $E$. The choice of the auxiliary Hilbert space fixes
M. Reyniers, G. C. Van de Steene, P. A. M. van Hoof, H. Van Winckel
One of the puzzling findings in the study of the chemical evolution of (post-)AGB stars is why very similar stars (in terms of metallicity, spectral type, infrared properties, etc...) show a very different photospheric composition. We aim at extending the still limited sample of s-process enriched post-AGB stars, in order to obtain a statistically large enou
F. Fehrer, P. M. Dinh, P. -G. Reinhard, E. Suraud
We discuss the structural properties and optical response of a small Na cluster inside rare gas (RG) matrices of Ne, Ar, or Kr atoms. The mixed systems are described with a hierarchical model, treating the cluster at a quantum mechanical level and the matrix atoms classically in terms of their positions and polarizations. We pay special attention to the diff
Antonio Diaz
We present a method to compute integral cohomology of posets. This toolbox is applicable as soon as the sub-posets under each object possess certain structure. This is the case for simplicial complexes and simplex-like posets. The method is based on homological algebra arguments in the category of functors and on a spectral sequence built upon the poset. We
Novel Master Formula for Twist-3 Soft-Gluon-Pole Mechanism to Single Transverse-Spin Asymmetry
hep-phYuji Koike, Kazuhiro Tanaka
We prove that twist-3 soft-gluon-pole (SGP) cross section for single spin asymmetries is determined by a certain ``primordial'' twist-2 cross section up to kinematic and color factors in the leading order perturbative QCD. This unveils universal structure behind the SGP cross sections in a variety of hard processes, and also the special role of the s
Po-Shen Loh, Benny Sudakov
Let G be a graph with n vertices, and let k be an integer dividing n. G is said to be strongly k-colorable if for every partition of V(G) into disjoint sets V_1 \cup ... \cup V_r, all of size exactly k, there exists a proper vertex k-coloring of G with each color appearing exactly once in each V_i. In the case when k does not divide n, G is defined to be str
A. Bialas, R. A. Janik, R. Peschanski
We propose a generalization of the Bjorken in-out Ansatz for fluid trajectories which, when applied to the (1+1) hydrodynamic equations, generates a one-parameter family of analytic solutions interpolating between the boost-invariant Bjorken picture and the non boost-invariant one by Landau. This parameter characterises the proper-time scale when the fluid v
T. S. Turova
We study the "rank 1 case" of the inhomogeneous random graph model. In the subcritical case we derive an exact formula for the asymptotic size of the largest connected component scaled to log n. This result is new, it completes the corresponding known result in the supercritical case. We provide some examples of application of a new formula.
jerome perez
This short review is devoted to the problem of the equilibrium of stellar dynamical systems in the context of the Vlasov-Poisson model. In a first part we will review some classical problems posed by the application of the Vlasov-Poisson model to the astrophysical systems like globular clusters or galaxies. In a second part we will recall some recent numeric
Anne-Laure Dalibard
We study the limit as $\e\to 0$ of the entropy solutions of the equation $\p_t \ue + \dv_x[A(\frac{x}{\e},\ue)] =0$. We prove that the sequence $\ue$ two-scale converges towards a function $u(t,x,y)$, and $u$ is the unique solution of a limit evolution problem. The remarkable point is that the limit problem is not a scalar conservation law, but rather a kine
Estelle Moraux, Jerome Bouvier, John Stauffer, David Barrado Y Navascues
We performed a deep wide field optical survey of the young (~100-150 Myr) open cluster Blanco1 to study its low mass population well down into the brown dwarf regime and estimate its mass function over the whole cluster mass range.The survey covers 2.3 square degrees in the I and z-bands down to I ~ z ~ 24 with the CFH12K camera. Considering two different cl
S. Cristallo, O. Straniero, M. T. Lederer, B. Aringer
The concomitant overabundances of C, N and s-process elements are commonly ascribed to the complex interplay of nucleosynthesis, mixing and mass loss taking place in Asymptotic Giant Branch stars. At low metallicity, the enhancement of C and/or N may be up to 1000 times larger than the original iron content and significantly affects the stellar structure and
M. Marseguerra, A. Zoia
In this paper we propose a comparison between the CTRW (Monte Carlo) and Fractional Derivative approaches to the modelling of anomalous diffusion phenomena in the presence of an advection field. Galilei variant and invariant schemes are revised.
Julien Larena, ; Jerome Perez
In this paper, we develop a method based on the analysis of the Kovalewski exponents to study the integrability of anisotropic and homogeneous Universes. The formalism is developed in scalar-tensor gravity, the general relativistic case appearing as a special case of this larger framework. Then, depending on the rationality of the Kovalewski exponents, the d
Measurement of the UHECR energy spectrum using data from the Surface Detector of the Pierre Auger Observatory
astro-phMarkus Roth
At the southern site of the Pierre Auger Observatory, which is close to completion, an exposure that significantly exceeds the largest forerunner experiments has already been accumulated. We report a measurement of the cosmic ray energy spectrum based on the high statistics collected by the surface detector. The methods developed to determine the spectrum fr
Normal and Anomalous Transport across an Interface: Monte Carlo and Analytical Approach
cond-mat.stat-mechM. Marseguerra, A. Zoia
In this paper we investigate the behavior of particles crossing a neat interface between two media. A Monte Carlo and analytical model, based on fractional derivatives, are presented and discussed in detail, together with a comparison. Anomalous and normal diffusion are consdered.
M. Marseguerra, A. Zoia
In this paper we deal with high-order corrections for the Fractional Derivative approach to anomalous diffusion, in super-diffusive regime, which become relevand whenever one attempts to describe the behavior of particles close to normal diffusion.
The Monte Carlo and fractional kinetics approaches to the underground anomalous subdiffusion of contaminants
cond-mat.stat-mechM. Marseguerra, A. Zoia
This paper deals with a comparison of Fractional Derivative and Monte carlo approaches to the modelling of anomalous diffusion in the field of particle transport. The goal of this research is to provide a better insight on the behavior of (radioactive) contaminant tracers when flowing through heterogeneous media.
Steven Watterson
It is shown that the flavour projection of staggered fermions can be written as a projection between the fields on four separate, but parallel, lattices, where the fields on each are modified forms of the standard staggered fermion field. Because the staggered Dirac operator acts equally on each lattice, it respects this flavour projection. We show that the
P. E. Jönsson, K. Takenaka, S. Niitaka, T. Sasagawa
Optical reflectivity measurements were performed on a single crystal of the d-electron heavy-fermion (HF) metal LiV2O4. The results evidence the highly incoherent character of the charge dynamics for all temperatures above T^* \approx 20 K. The spectral weight of the optical conductivity is redistributed over extremely broad energy scales (~ 5 eV) as the qua
E. K. Irish
A generalized version of the rotating-wave approximation for the single-mode spin-boson Hamiltonian is presented. It is shown that performing a simple change of basis prior to eliminating the off-resonant terms results in a significantly more accurate expression for the energy levels of the system. The generalized approximation works for all values of the co
On the relation between the proton-air cross section and fluctuations of the shower longitudinal profile
astro-phR. Ulrich, J. Blümer, R. Engel, F. Schüssler
The current status and prospects of deducing the proton-air cross section from fluorescence telescope measurements of extensive air showers are discussed. As it is not possible to observe the point of first interaction, $X_ {\rm 1}$, directly, other observables closely linked to $X_{\rm 1}$ must be inferred from the measured longitudinal profiles. This intro
Quantum phase transitions in a resonant-level model with dissipation: Renormalization-group studies
cond-mat.str-elChung-Hou Chung, Matthew T. Glossop, Lars Fritz, Marijana Kirćan
We study a spinless level that hybridizes with a fermionic band and is also coupled via its charge to a dissipative bosonic bath. We consider the general case of a power-law hybridization function $Γ(\w)\propto |\w|^r$ with $r\ge 0$, and a bosonic bath spectral function $B(\w)\propto \w^s$ with $s\ge -1$. For $r<1$ and $\mathrm{max}(0,2r-1)<s<1$, this Bose-F