Skip to main content
Internet Archive's 25th Anniversary Logo

55,274
UPLOADS


More right-solid

Show sorted alphabetically

Show sorted alphabetically

More right-solid

More right-solid
SHOW DETAILS
eye
Title
Date Archived
Creator
Arxiv.org
texts

eye 11

favorite 0

comment 0

Convenient Cutkosky-like diagrammatic rules for computing the spectral densities of arbitrary two-point correlation functions in finite temperature field theory are derived. The approach is based on an explicit analytic continuation of imaginary-time Feynman diagrams and avoids the complications of real-time finite temperature perturbation theory. The application of this method to the perturbative evaluation of transport coefficients is briefly discussed.
Source: http://arxiv.org/abs/hep-ph/9210227v1
Arxiv.org
texts

eye 20

favorite 0

comment 0

We discuss the consequences of recent experimental results from CDF, SLC, LEP and elsewhere for the Standard Model and for new physics. A global fit to all indirect precision data yields $m_t = 175 \pm 11^{+17}_{-19}$~GeV, $\sin^2\theta_{MS} = 0.2317(3)(2)$, and $\alpha_s = 0.127(5)(2)$, where the central values are for $M_H = 300$ GeV and the second uncertainties are for $M_H \rightarrow 1000$ GeV (+) and 60 GeV (-). The $m_t$ value is in remarkable agreement with the value $m_t=174 \pm 16$...
Source: http://arxiv.org/abs/hep-ph/9411203v1
Arxiv.org
by Dan Kiselman
texts

eye 10

favorite 0

comment 0

The formation of the resonance lines of neutral boron in solar-type stellar atmospheres is investigated taking into account effects of departures from local thermodynamic equilibrium (NLTE effects). The latter are due to a combination of overionisation and optical pumping in resonance lines, both caused by the hot, non-local, ultraviolet radiation fields in the line-forming regions. They lead to an underestimation of the boron abundance when analysis methods assuming local thermodynamic...
Source: http://arxiv.org/abs/astro-ph/9401018v1
Arxiv.org
by M. Joyce; T. Prokopec; N. Turok
texts

eye 13

favorite 0

comment 0

In unconstrained thermal equilibrium a local potential for total or fermionic hypercharge does not bias electroweak anomalous processes. We consider two proposed mechanisms for electroweak baryogenesis in this light. In `spontaneous' baryogenesis, which was argued to apply in the `adiabatic' limit of thick, slow walls, a non-zero result was obtained by setting globally conserved charges to be zero {\it locally}. We show that this is a poor approximation unless the walls are very thick. For more...
Source: http://arxiv.org/abs/hep-ph/9401351v3
Arxiv.org
texts

eye 11

favorite 0

comment 0

We study the nonequilibrium dynamics of line liquids as realized in the nonlinear motion of flux lines of a superconductor driven by an applied electric current. Our analysis suggests a transition in the dynamics of the lines from a smooth, laminar phase at small driving forces, to a rough, turbulent phase when the drive is increased. We explore the nature of these phases and describe interesting analogies to driven diffusion and growing interfaces.
Source: http://arxiv.org/abs/cond-mat/9206008v1
Arxiv.org
by Ulrike von Luxburg; Mikhail Belkin; Olivier Bousquet
texts

eye 86

favorite 0

comment 0

Consistency is a key property of all statistical procedures analyzing randomly sampled data. Surprisingly, despite decades of work, little is known about consistency of most clustering algorithms. In this paper we investigate consistency of the popular family of spectral clustering algorithms, which clusters the data with the help of eigenvectors of graph Laplacian matrices. We develop new methods to establish that, for increasing sample size, those eigenvectors converge to the eigenvectors of...
Source: http://arxiv.org/abs/0804.0678v1
Arxiv.org
by Mu-Tao Wang; Shing-Tung Yau
texts

eye 51

favorite 0

comment 0

There have been many attempts to define the notion of quasilocal mass for a spacelike 2-surface in spacetime by the Hamilton-Jacobi analysis. The essential difficulty in this approach is to identify the right choice of the background configuration to be subtracted from the physical Hamiltonian. Quasilocal mass should be nonnegative for surfaces in general spacetime and zero for surfaces in flat spacetime. In this letter, we propose a new definition of gauge-independent quasilocal mass and prove...
Source: http://arxiv.org/abs/0804.1174v3
Arxiv.org
texts

eye 40

favorite 0

comment 0

We consider the Langevin equation describing a stochastically perturbed by uniform noise non-viscous Burgers fluid and introduce a deterministic function that corresponds to the mean of the velocity when we keep the value of position fixed. We study interrelations between this function and the solution of the non-perturbed Burgers equation. Especially we are interested in the property of the solution of the latter equation to develop unbounded gradients within a finite time. We study the...
Source: http://arxiv.org/abs/0804.1553v3
Arxiv.org
texts

eye 66

favorite 0

comment 0

A new approximation scheme to the centrifugal term is proposed to obtain the $l\neq 0$ solutions of the Schr\"{o}dinger equation with the Manning-Rosen potential. We also find the corresponding normalized wave functions in terms of the Jacobi polynomials. To show the accuracy of the new approximation scheme, we calculate the energy eigenvalues numerically for arbitrary quantum numbers $n$ and $l$ with two different values of the potential parameter $\alpha .$ The bound state energies of...
Source: http://arxiv.org/abs/0807.2085v1
Arxiv.org
by Michal Deák; Hannes Jung; Krzysztof Kutak
texts

eye 42

favorite 0

comment 0

We study in the $k_T$ factorisation framework jet production at LHC energies. In particular we are interested in valence quark and gluon initiated jets. The calculation of the relevant hard matrix element is presented. A CCFM like evolutionequation for valence quark distribution is solved and the cross section for valence quark and gluon initiated process is calculated using Monte Carlo event generator CASCADE.
Source: http://arxiv.org/abs/0807.2403v1
Arxiv.org
by Edgar M. Blokhuis; Joris Kuipers; Richard Vink
texts

eye 52

favorite 0

comment 0

To describe the full spectrum of surface fluctuations of the interface between phase-separated colloid-polymer mixtures from low scattering vector q (classical capillary wave theory) to high q (bulk-like fluctuations), one must take account of the interface's bending rigidity. We find that the bending rigidity is negative and that on approach to the critical point it vanishes proportionally to the interfacial tension. Both features are in agreement with Monte Carlo simulations.
Source: http://arxiv.org/abs/0807.3456v1
Arxiv.org
texts

eye 59

favorite 0

comment 0

The relation between quantum phase transitions, entanglement, and geometric phases is investigated with a system of two qubits with XY type interaction. A seam of level crossings of the system is a circle in parameter space of the anisotropic coupling and the transverse magnetic field, which is identical to the disorder line of an one-dimensional XY model. The entanglement of the ground state changes abruptly as the parameters vary across the circle except specific points crossing to the...
Source: http://arxiv.org/abs/0807.4662v1
Arxiv.org
by A. Alkin; O. Kovalenko; E. Martynov
texts

eye 107

favorite 0

comment 0

The standard Regge poles are considered as inputs for two unitarization methods: eikonal and U-matrix. It is shown that only models with three input pomerons and two input odderons can describe the high energy data on $pp$ and $\bar pp$ elastic scattering including the new data from Tevatron and LHC. However, it seems that the both considered models (eikonal and U-matrix) require a further modification (e.g., to explore nonlinear reggeon trajectories and/or nonexponential vertex functions) for...
Source: http://arxiv.org/abs/1304.0850v2
Arxiv.org
texts

eye 89

favorite 0

comment 0

In this note we analyse the propagation of a small density perturbation in a one-dimensional compressible fluid by means of fractional calculus modelling, replacing thus the ordinary time derivative with the Caputo fractional derivative in the constitutive equations. By doing so, we embrace a vast phenomenology, including subdiffusive, superdiffusive and also memoryless processes like classical diffusions. From a mathematical point of view, we study systems of coupled fractional equations,...
Source: http://arxiv.org/abs/1304.1055v1
Arxiv.org
texts

eye 44

favorite 0

comment 0

We separate the $AF$-algebras (correspondingly action of the countable groups on Cantor sets) onto two classes ---- "completely smooth" for which the set of all indecomposable traces (correspondingly list of all invariant ergodic measures) has nice parametrization, and the second class --- "completely non-smooth" for which the set of all traces (correspondingly set of all invariant measures) is Poulsen simplex and therefore there is no suitable parametrization of...
Source: http://arxiv.org/abs/1304.2193v1
Arxiv.org
by Tran Doan Huan; Maximilian Amsler; Riccardo Sabatini; Vu Ngoc Tuoc; Nam Ba Le; Lilia M. Woods; Nicola Marzari; Stefan Goedecker
texts

eye 143

favorite 0

comment 0

We study the thermodynamic stability at low temperatures of a series of alkali metal/zinc double-cation borohydrides, including LiZn(BH$_4$)$_3$, LiZn$_2$(BH$_4$)$_5$, NaZn(BH$_4$)$_3$, NaZn$_2$(BH$_4$)$_5$, KZn(BH$_4$)$_3$, and KZn$_2$(BH$_4$)$_5$. While LiZn$_2$(BH$_4$)$_5$, NaZn(BH$_4$)$_3$, NaZn$_2$(BH$_4$)$_5$ and KZn(BH$_4$)$_3$ were recently synthesized, LiZn(BH$_4$)$_3$ and KZn$_2$(BH$_4$)$_5$ are hypothetical compounds. Using the minima-hopping method, we discover two new lowest-energy...
Source: http://arxiv.org/abs/1304.4088v2
Arxiv.org
by Said Jabbour; Lakhdar Sais; Yakoub Salhi
texts

eye 109

favorite 0

comment 0

In this paper, we propose a first application of data mining techniques to propositional satisfiability. Our proposed Mining4SAT approach aims to discover and to exploit hidden structural knowledge for reducing the size of propositional formulae in conjunctive normal form (CNF). Mining4SAT combines both frequent itemset mining techniques and Tseitin's encoding for a compact representation of CNF formulae. The experiments of our Mining4SAT approach show interesting reductions of the sizes of...
Source: http://arxiv.org/abs/1304.4415v1
Arxiv.org
by Wei Xiong; Jefferson Zhe Liu; Zhiliang Zhang; Quanshui Zheng
texts

eye 119

favorite 0

comment 0

Reversible control of surface wettability has wide applications in lab-on-chip systems, tunable optical lenses, and microfluidic tools. Using a graphene sheet as a sample material and molecular dynamic (MD) simulations, we demonstrate that strain engineering can serve as an effective way to control the surface wettability. The contact angles $\theta$ of water droplets on a graphene vary from 72.5$^\circ$ to 106$^\circ$ under biaxial strains ranging from -10% to 10% that are applied on the...
Source: http://arxiv.org/abs/1304.4770v1
Arxiv.org
by Rolf T. Horn; Piotr Kolenderski; Dongpeng Kang; Carmelo Scarcella; Adriano Della Frera; Alberto Tosi; Lukas G. Helt; Sergei V. Zhukovsky; John E. Sipe; Gregor Weihs; Amr S. Helmy; Thomas Jennewein
texts

eye 105

favorite 0

comment 0

Creating miniature chip scale implementations of optical quantum information protocols is a dream for many in the quantum optics community. This is largely because of the promise of stability and scalability. Here we present a monolithically integratable chip architecture upon which is built a photonic device primitive called a Bragg reflection waveguide (BRW). Implemented in gallium arsenide, we show that, via the process of spontaneous parametric down conversion, the BRW is capable of...
Source: http://arxiv.org/abs/1304.4944v1
Arxiv.org
by U. Bissbort; D. Cocks; A. Negretti; Z. Idziaszek; T. Calarco; F. Schmidt-Kaler; W. Hofstetter; R. Gerritsma
texts

eye 142

favorite 0

comment 0

We propose and theoretically investigate a hybrid system composed of a crystal of trapped ions coupled to a cloud of ultracold fermions. The ions form a periodic lattice and induce a band structure in the atoms. This system combines the advantages of scalability and tunability of ultracold atomic systems with the high fidelity operations and detection offered by trapped ion systems. It also features close analogies to natural solid-state systems, as the atomic degrees of freedom couple to...
Source: http://arxiv.org/abs/1304.4972v1
Arxiv.org
by Francisco de la Hoz; Luis Vega
texts

eye 61

favorite 0

comment 0

In this paper, we study the evolution of the localized induction approximation (LIA), also known as vortex filament equation, $$ \mathbf X_t = \mathbf X_s \wedge \mathbf X_{ss}, $$ for $\mathbf X(s, 0)$ a regular planar polygon. Using algebraic techniques, supported by full numerical simulations, we give strong evidence that $\mathbf X(s, t)$ is also a polygon at any rational time; moreover, it can be fully characterized, up to a rigid movement, by a generalized quadratic Gau{\ss} sum. We also...
Source: http://arxiv.org/abs/1304.5521v1
Arxiv.org
by Yves Revaz; Daniel Pfenniger
texts

eye 79

favorite 0

comment 0

Two methods generating warped galaxies with N-body simulations are presented. One uses an external potential as a disturber while the other is based on material accretion. The results of both methods are compared. A particular attention is given on the shape of the line of node (LON).
Source: http://arxiv.org/abs/astro-ph/0009053v1
Arxiv.org
by I. Iwata; K. Ohta; K. Nakanishi; K. Kohno; R. G. McMahon
texts

eye 68

favorite 0

comment 0

We present a result of the quasar CO(J=6-5) observations of SDSSp J104433.04-012502.2 at z = 5.8. Ten-days observations with the Nobeyama Millimeter Array yielded an rms noise level of ~ 2.1 mJy/beam in a frequency range from 101.28 GHz to 101.99 GHz at a velocity resolution of 120 km/s. No significant clear emission line was detected in the observed field and frequency range. Three sigma upper limit on the CO(J=6-5) luminosity of the object is 2.8 x 10^10 K km/s pc^2, corresponding to a...
Source: http://arxiv.org/abs/astro-ph/0107369v1
Arxiv.org
by M. Ali-Akbari
texts

eye 101

favorite 0

comment 0

We consider a D2-brane in the pp-wave backgrounds obtained from AdS$_4\times$CP$^3$ when electric and magnetic fields have been turned on. Upon fixing the light-cone gauge, light-cone Hamiltonian and BPS configurations are obtained. In particular we study BPS configurations with electric dipole on the two sphere giant and a giant graviton rotating in transverse directions. Moreover we show that the gauge field living on the D2-brane is replaced by a scalar field in the light-cone Hamiltonian....
Source: http://arxiv.org/abs/1005.0126v1
Arxiv.org
by Lijing Shao; Bo-Qiang Ma
texts

eye 43

favorite 0

comment 0

The occurrence of the nonzero leftmost digit, i.e., 1, 2, ..., 9, of numbers from many real world sources is not uniformly distributed as one might naively expect, but instead, the nature favors smaller ones according to a logarithmic distribution, named Benford's law. We investigate three kinds of widely used physical statistics, i.e., the Boltzmann-Gibbs (BG) distribution, the Fermi-Dirac (FD) distribution, and the Bose-Einstein (BE) distribution, and find that the BG and FD distributions...
Source: http://arxiv.org/abs/1005.0660v1
Arxiv.org
by D. Volovik; S. Redner
texts

eye 67

favorite 0

comment 0

We investigate the first-passage properties of bursty random walks on a finite one-dimensional interval of length L, in which unit-length steps to the left occur with probability close to one, while steps of length b to the right -- "bursts" -- occur with small probability. This stochastic process provides a crude description of the early stages of virus spread in an organism after exposure. The interesting regime arises when b is of the order of but less than 1, where the conditional...
Source: http://arxiv.org/abs/1005.1579v2
Arxiv.org
by P. P. Van der Werf; K. G. Isaak; R. Meijerink; M. Spaans; A. Rykala; T. Fulton; A. F. Loenen; F. Walter; A. Weiss; L. Armus; J. Fischer; F. P. Israel; A. I. Harris; S. Veilleux; C. Henkel; G. Savini; S. Lord; H. A. Smith; E. Gonzalez-Alfonso; D. Naylor; S. Aalto; V. Charmandaris; K. M. Dasyra; A. Evans; Y. Gao; T. R. Greve; R. Guesten; C. Kramer; J. Martin-Pintado; J. Mazzarella; P. P. Papadopoulos; D. B. Sanders; L. Spinoglio; G. Stacey; C. Vlahakis; M. C. Wiedner; E. M. Xilouris
texts

eye 29

favorite 0

comment 0

We present a full high resolution SPIRE FTS spectrum of the nearby ultraluminous infrared galaxy Mrk231. In total 25 lines are detected, including CO J=5-4 through J=13-12, 7 rotational lines of H2O, 3 of OH+ and one line each of H2O+, CH+, and HF. We find that the excitation of the CO rotational levels up to J=8 can be accounted for by UV radiation from star formation. However, the approximately flat luminosity distribution of the CO lines over the rotational ladder above J=8 requires the...
Source: http://arxiv.org/abs/1005.2877v1
Arxiv.org
by G. Risaliti; M. Elvis; S. Bianchi; G. Matt
texts

eye 71

favorite 0

comment 0

We present a Chandra monitoring campaign of the highly variable Seyfert galaxy UGC 4203 (the "Phoenix Galaxy") which revealed variations in the X-ray absorbing column density on time scales of two weeks. This is the third, clear case, after NGC 1365 and NGC 7582, of dramatic N_H variability on short time scales observed in a "changing look" source, i.e. an AGN observed in the past in both a reflection-dominated and a Compton-thin state. The inferred limits on the distance of...
Source: http://arxiv.org/abs/1005.3052v2
Arxiv.org
texts

eye 98

favorite 0

comment 0

We investigate how to effectively preserve the entanglement between two noninteracting multilevel oscillators coupled to a common reservoir under non-ideal pulse control. A universal characterization using fidelity is developed for the behavior of the system based on Nakajima-Zwanzig projection operator technique. Our analysis includes the validity of the approximation method and the decoherence-suppression by the non-ideal pulse control. The power of our strategy for protecting entanglement is...
Source: http://arxiv.org/abs/1005.3171v1
Arxiv.org
by Peter Zeiler Skands
texts

eye 42

favorite 0

comment 0

We present 9 new tunes of the pT-ordered shower and underlying-event model in PYTHIA 6.4. These "Perugia" tunes update and supersede the older "S0" family. The data sets used to constrain the models include hadronic Z0 decays at LEP, Tevatron minimum-bias data at 630, 1800, and 1960 GeV, Tevatron Drell-Yan data at 1800 and 1960 GeV, and SPS min-bias data at 200, 546, and 900 GeV. In addition to the central parameter set, called "Perugia 0", we introduce a set of 8...
Source: http://arxiv.org/abs/1005.3457v4
Arxiv.org
texts

eye 117

favorite 0

comment 0

We discuss semiclassical expansions around a class of classical string configurations lying in AdS_3 x S^1 using the Pohlmeyer-reduced from of the AdS_5 x S^5 superstring theory. The Pohlmeyer reduction of the AdS_5 x S^5 superstring theory is a gauged Wess-Zumino-Witten model with an integrable potential and two-dimensional fermionic fields. It was recently conjectured that the quantum string partition function is equal to the quantum reduced theory partition function. Continuing the previous...
Source: http://arxiv.org/abs/1005.4386v2
Arxiv.org
by K. Perraut; M. Benisty; D. Mourard; S. Rajabi; F. Bacciotti; Ph. Bério; D. Bonneau; O. Chesneau; J. M. Clausse; O. Delaa; A. Marcotto; A. Roussel; A. Spang; Ph. Stee; I. Tallon-Bosc; H. McAlister; T. ten Brummelaar; J. Sturmann; L. Sturmann; N. Turner; C. Farrington; P. J. Goldfinger
texts

eye 69

favorite 0

comment 0

A crucial issue in star formation is to understand the physical mechanism by which mass is accreted onto and ejected by a young star. The visible spectrometer VEGA on the CHARA array can be an efficient means of probing the structure and the kinematics of the hot circumstellar gas at sub-AU. For the first time, we observed the Herbig Ae star AB Aur in the H$\alpha$ emission line, using the VEGA low spectral resolution on two baselines of the array. We computed and calibrated the spectral...
Source: http://arxiv.org/abs/1005.5267v1
Arxiv.org
by H. S. Ruiz; A. Bad\'\ia-Majós
texts

eye 97

favorite 0

comment 0

Several aspects of the general theory for the critical states of a vortex lattice and the magnetic flux dynamics in type-II superconductors are examined by a direct variational optimisation method and widespread physical principles. Our method allows to unify a number of conventional models describing the complex vortex configurations in the critical state regime. Special attention is given to the discussion of the relation between the flux-line cutting mechanism and the depinning threshold...
Source: http://arxiv.org/abs/1005.5540v1
Arxiv.org
by Simone Gasparinetti; Fabio Deon; Giorgio Biasiol; Lucia Sorba; Fabio Beltram; Francesco Giazotto
texts

eye 55

favorite 0

comment 0

We demonstrate local detection of the electron temperature in a two-dimensionalmicrodomain using a quantum dot. Our method relies on the observation that a temperature bias across the dot changes the functional form of Coulomb-blockade peaks. We apply our results to the investigation of electron-energy relaxation at subkelvin temperatures, find that the energy flux from electrons into phonons is proportional to the fifth power of temperature, and give a measurement of the coupling constant.
Source: http://arxiv.org/abs/1007.0172v2
Arxiv.org
by J. Bouttier; E. Guitter
texts

eye 41

favorite 0

comment 0

We present an unexpected connection between two map enumeration problems. The first one consists in counting planar maps with a boundary of prescribed length. The second one consists in counting planar maps with two points at a prescribed distance. We show that, in the general class of maps with controlled face degrees, the solution for both problems is actually encoded into the same quantity, respectively via its power series expansion and its continued fraction expansion. We then use known...
Source: http://arxiv.org/abs/1007.0419v3
Arxiv.org
by João Gouveia; Rekha R. Thomas
texts

eye 31

favorite 0

comment 0

This article describes a method to compute successive convex approximations of the convex hull of a set of points in R^n that are the solutions to a system of polynomial equations over the reals. The method relies on sums of squares of polynomials and the dual theory of moment matrices. The main feature of the technique is that all computations are done modulo the ideal generated by the polynomials defining the set to the convexified. This work was motivated by questions raised by Lov\'asz...
Source: http://arxiv.org/abs/1007.1191v1
Arxiv.org
texts

eye 127

favorite 0

comment 0

Linux package managers have to deal with dependencies and conflicts of packages required to be installed by the user. As an NP-complete problem, this is a hard task to solve. In this context, several approaches have been pursued. Apt-pbo is a package manager based on the apt project that encodes the dependency solving problem as a pseudo-Boolean optimization (PBO) problem. This paper compares different PBO solvers and their effectiveness on solving the dependency solving problem.
Source: http://arxiv.org/abs/1007.1022v1
Arxiv.org
by B. Letarte; V. Hill; E. Tolstoy; P. Jablonka; M. Shetrone; K. A. Venn; M. Spite; M. J. Irwin; G. Battaglia; A. Helmi; F. Primas; P. Francois; A. Kaufer; T. Szeifert; N. Arimoto; K. Sadakane
texts

eye 84

favorite 0

comment 0

For the first time we show the detailed late-stage chemical evolution history of small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high resolution (R$\sim$20000) FLAMES/GIRAFFE abundance study at ESO/VLT of 81 photometrically selected red giant branch stars in the central 25$'$ of the Fornax dwarf spheroidal galaxy. We present abundances of \alfe\ (Mg, Si, Ca and Ti), iron-peak elements (Fe, Ni and Cr) and heavy elements (Y, Ba, La, Nd and Eu). Our sample was...
Source: http://arxiv.org/abs/1007.1007v1
Arxiv.org
by I. Krasovsky
texts

eye 97

favorite 0

comment 0

We outline an approach recently used to prove formulae for the multiplicative constants in the asymptotics for the sine-kernel and Airy-kernel determinants appearing in random matrix theory and related areas.
Source: http://arxiv.org/abs/1007.1135v1
Arxiv.org
by S. G. Chigarev; E. M. Epshtein; Yu. V. Gulyaev; P. E. Zilberman
texts

eye 84

favorite 0

comment 0

The stability is analyzed of the equilibrium configurations of a magnetic junction with a free layer that has cubic symmetry and two anisotropy axes in the layer plane. Different variants of the switching between various configurations are considered. A possibility is shown of the substantial lowering of the threshold current density needed for the switching. Numerical simulation is made of the switching dynamics for various configurations.
Source: http://arxiv.org/abs/1007.2097v1
Arxiv.org
by Gianluca Giovannetti; Sanjeev Kumar; Alessandro Stroppa; Jeroen van den Brink; Silvia Picozzi; Jose Lorenzana
texts

eye 97

favorite 0

comment 0

Cupric oxide is multiferroic at unusual high temperatures. From density functional calculations we find that the low-T magnetic phase is paraelectric and the higher-T one ferroelectric, with a size and direction of polarization in good agreement with experiment. By mapping of the ab initio results on an effective spin model we find with Monte Carlo that in the high-T magnetic state non-collinearity and inversion symmetry breaking stabilize each other via the Dzyaloshinskii Moriya interaction....
Source: http://arxiv.org/abs/1007.3220v2
Arxiv.org
by Aya Bamba; Takayasu Anada; Tadayasu Dotani; Koji Mori; Ryo Yamazaki; Ken Ebisawa; Jacco Vink
texts

eye 162

favorite 0

comment 0

During the search for counterparts of very-high-energy gamma-ray sources, we serendipitously discovered large, extended, low surface brightness emission from PWNe around pulsars with the ages up to ~100 kyrs, a discovery made possible by the low and stable background of the Suzaku X-ray satellite. A systematic study of a sample of 8 of these PWNe, together with Chandra datasets, has revealed us that the nebulae keep expanding up to for ~100 kyrs, although time scale of the synchrotron X-ray...
Source: http://arxiv.org/abs/1007.3203v1
Arxiv.org
texts

eye 40

favorite 0

comment 0

In this report, firstly, we presents state of the art survey on Data Management and Data Dissemination techniques with Mobile Sink. Moreover we classify these techniques into two ample sub-categories. Under this classification, we identify, review, compare, and highlight these techniques and their pros and cons. We do a SWOT (Strength, Weaknesses, Opportunities, Threats) analysis of each scheme. We also discuss where each scheme is appropriate. Secondly, we presents a new distributed data...
Source: http://arxiv.org/abs/1007.4068v2
Arxiv.org
by Artur Siemaszko; Maciej P. Wojtkowski
texts

eye 53

favorite 0

comment 0

We call a Markov partition of a two dimensional hyperbolic toral automorphism a Berg partition if it contains just two rectangles. We describe all Berg partitions for a given hyperbolic toral automorphism. In particular there are exactly (k + n + l + m)/2 nonequivalent Berg partitions with the same connectivity matrix (k, l, m, n).
Source: http://arxiv.org/abs/1007.3984v1
Arxiv.org
texts

eye 80

favorite 0

comment 0

We review the interplay of frustration and strong electronic correlations in quasi-two-dimensional organic charge transfer salts, such as k-(BEDT-TTF)_2X and Et_nMe_{4-n}Pn[Pd(dmit)2]2. These two forces drive a range of exotic phases including spin liquids, valence bond crystals, pseudogapped metals, and unconventional superconductivity. Of particular interest is that in several materials there is a direct transition as a function of pressure from a spin liquid Mott insulating state to a...
Source: http://arxiv.org/abs/1007.5381v2
This paper concerns continuous dependence estimates for Hamilton-Jacobi-Bellman-Isaacs operators (briefly, HJBI). For the parabolic Cauchy problem, we establish such an estimate in the whole space $[0,+\infty)\times\Rn$. Moreover, under some periodicity and ellipticity assumptions, we obtain a similar estimate for the ergodic constant associated to the HJBI operator. An interesting byproduct of the latter result will be the local uniform convergence for some classes of singular perturbation...
Source: http://arxiv.org/abs/1007.5445v1
Arxiv.org
by Sona Pochybova
texts

eye 134

favorite 0

comment 0

The separate study of quark and gluon jets is vital for the interpretation of multiple variables behaviour observed in both high-energy hadron and heavy-ion collisions in the present and future experiments. We propose a set of jet-energy dependent cuts to be used to distinguish between quark and gluon jets experimentally based on a Monte-Carlo study of their properties. Further, we introduce the possibility to calibrate these cuts via gamma-jet and multi-jet events, which represent clean...
Source: http://arxiv.org/abs/1107.0128v1
Arxiv.org
texts

eye 37

favorite 0

comment 0

The CKM angle $\gamma/\phi_{3}$ had been measured by two B-factories, the PEPII collider for the BaBar experiment and the KEKB collider for the Belle experiments. The present paper reports recent progress in $\gamma/\phi_{3}$.
Source: http://arxiv.org/abs/1107.0159v3
Arxiv.org
by A. -M. Uimonen; E. Khosravi; A. Stan; G. Stefanucci; S. Kurth; R. van Leeuwen; E. K. U. Gross
texts

eye 108

favorite 0

comment 0

We study time-dependent electron transport through an Anderson model. The electronic interactions on the impurity site are included via the self-energy approximations at Hartree-Fock (HF), second Born (2B), GW, and T-Matrix level as well as within a time-dependent density functional (TDDFT) scheme based on the adiabatic Bethe-Ansatz local density approximation (ABALDA) for the exchange correlation potential. The Anderson model is driven out of equilibrium by applying a bias to the leads and its...
Source: http://arxiv.org/abs/1107.0162v2
Arxiv.org
by Kiran Jain; S. C. Tripathy; F. Hill
texts

eye 74

favorite 0

comment 0

In this paper, we address the controversy regarding the recent extended solar minimum as seen in helioseismic low- and intermediate-degree mode frequencies: studies from different instruments identify different epochs of seismic minima. Here we use mode frequencies from a network of six identical instruments, Global Oscillation Network Group, continuously collecting data for more than 15 years, to investigate the epoch of minimum in solar oscillation frequencies prior to the beginning of solar...
Source: http://arxiv.org/abs/1107.0049v1
Arxiv.org
by Linyuan Lü; Duan-Bing Chen; Tao Zhou
texts

eye 110

favorite 0

comment 0

Spreading dynamics of information and diseases are usually analyzed by using a unified framework and analogous models. In this paper, we propose a model to emphasize the essential difference between information spreading and epidemic spreading, where the memory effects, the social reinforcement and the non-redundancy of contacts are taken into account. Under certain conditions, the information spreads faster and broader in regular networks than in random networks, which to some extent supports...
Source: http://arxiv.org/abs/1107.0429v2
Arxiv.org
by K. P. Khemchandani; A. Martínez Torres; H. Kaneko; H. Nagahiro; A. Hosaka
texts

eye 139

favorite 0

comment 0

A study of meson-baryon systems with total strangeness -1 is made within a framework based on the chiral and hidden local symmetries. These systems consist of octet baryons, pseudoscalar and vector mesons. The pseudoscalar meson-baryon (PB) dynamics has been earlier found determinant for the existence of some strangeness -1 resonances, for example, $\Lambda(1405)$, $\Lambda(1670)$, etc. The motivation of the present work is to study the effect of coupling the closed vector meson-baryon (VB)...
Source: http://arxiv.org/abs/1107.0574v2
We study, in the semi-classical approximation, the convergence of the quantum density and the quantum action, solutions to the Madelung equations, when the Planck constant h tends to 0. We find two different solutions which depend to the initial density . In the first case where the initial quantum density is a classical density rho_0(x), the quantum density and the quantum action converge to a classical action and a classical density which satisfy the statistical Hamilton-Jacobi equations....
Source: http://arxiv.org/abs/1107.0790v1
Arxiv.org
texts

eye 46

favorite 0

comment 0

Recent observations have revealed the emergence of an unusual normal phase when a magnetic flux threads an ultra-thin superconducting cylinder. Moreover, with increasing temperature, the resistance rises in a series of abrupt jumps. These phenomena are explained using a novel approach, which allows calculation of the resistance in the presence of amplitude and phase fluctuations of the superconducting order parameter, and at the same time introduces a local probe of the current and chemical...
Source: http://arxiv.org/abs/1107.1246v2
Arxiv.org
texts

eye 53

favorite 0

comment 0

General relativity under the assumption of noncommuting components of the tetrad field is considered in this paper. Since the algebraic properties of the tetrad field representing the gravitational field are assumed to correspond to the noncommutativity algebra of the coordinates in the canonical case of noncommutative geometry, this idea is closely related to noncommutative geometry as well as to canonical quantization of gravity. According to this presupposition generalized field equations...
Source: http://arxiv.org/abs/1107.1071v2
Arxiv.org
by Tizita Nesibu Shewaye
texts

eye 143

favorite 0

comment 0

This work presents an automatic human gender and age group recognition system based on human facial images. It makes an extensive experiment with row pixel intensity valued features and Discrete Cosine Transform (DCT) coefficient features with Principal Component Analysis and k-Nearest Neighbor classification to identify the best recognition approach. The final results show approaches using DCT coefficient outperform their counter parts resulting in a 99% correct gender recognition rate and 68%...
Source: http://arxiv.org/abs/1304.0019v1
Arxiv.org
by Tarek Sayed Ahmed
texts

eye 52

favorite 0

comment 0

We show that cylindric polyadic algebras introduced by Ferenczi has the superamalgmation property. We give two proofs. One is a Henkin construction, and the other is inspired by duality theory in modal logic between finite zig zag products of Kripke frames and their complex algebras.
Source: http://arxiv.org/abs/1304.0724v1
Arxiv.org
by Andre Walker-Loud
texts

eye 104

favorite 0

comment 0

Anchoring our understanding of low-energy nuclear and hadronic physics to the fundamental theory of strong interactions, QCD, remains and outstanding challenge for physicists. Lattice QCD and chiral perturbation theory are the most powerful theoretical tools we have at our disposal to make this connection. These tools share a symbiotic relationship as chiral perturbation theory is used to understand the light quark mass dependence of observables, while lattice QCD is used to determine the...
Source: http://arxiv.org/abs/1304.6341v2
Arxiv.org
texts

eye 51

favorite 0

comment 0

We combine the finite size scaling method with the meshfree spectral method to calculate quantum critical parameters for a given Hamiltonian. The basic idea is to expand the exact wave function in a finite exponential basis set and extrapolate the information about system criticality from a finite basis to the infinite basis set limit. The used exponential basis set -though chosen intuitively- allows handling a very wide range of exponential decay rates and calculating multiple eigenvalues...
Source: http://arxiv.org/abs/1304.7433v1
Arxiv.org
by D. Lutz; R. Genzel; E. Sturm; L. Tacconi; E. Wieprecht; T. Alexander; H. Netzer; A. Sternberg; A. F. M. Moorwood; R. A. E. Fosbury; K. Fricke; S. J. Wagner; A. Quirrenbach; H. Awaki; K. Y. Lo
texts

eye 55

favorite 0

comment 0

We report infrared spectroscopy of the prototypical Seyfert 2 galaxy NGC 1068, aiming at detection of broad components of hydrogen recombination lines that originate in the obscured broad-line region. Using the Short Wavelength Spectrometer on board the Infrared Space Observatory, we have observed for the first time the regions of Brackett beta 2.626um and Pfund alpha 7.460um, and present improved data for Brackett alpha 4.052um. No significant broad components are detected, implying an...
Source: http://arxiv.org/abs/astro-ph/9910101v1
Arxiv.org
by A. J. Benson; C. M. Baugh; S. Cole; C. S. Frenk; C. G. Lacey
texts

eye 34

favorite 0

comment 0

We use a combination of N-body simulations of the hierarchical clustering of dark matter and semi-analytic modelling of the physics of galaxy formation to probe the relationship between the galaxy distribution and the mass distribution. The pairwise line-of-sight velocity dispersion of galaxies is sensitive to the number of galaxies present in halos of different mass. The galaxy velocity dispersion is ~40% lower than that of the dark matter and is in reasonable agreement with the values...
Source: http://arxiv.org/abs/astro-ph/9910488v2
Arxiv.org
by R. Mohayaee
texts

eye 11

favorite 0

comment 0

We consider the anomalies of $W_\infty$ gravity in the context of path-integralquantization. We derive the ghost-loop anomalies to all orders in $\hbar$ directly from the path-integral measure by the Fujikawa method. We also show that in the matter sector the higher-loop anomalies can be obtained by implementation of the Wess-Zumino consistency condition using the one-loop anomaly. Cancellation of the anomalies between these two sectors then leaves the theory anomaly-free.
Source: http://arxiv.org/abs/hep-th/9407006v1
We consider the effect of the nearest neighbour copper-oxygen repulsion, V, when coupled to the charge transfer resonances Cu2+ to Cu3+ and Cu2+ to Cu+ in the high temperature cuprate superconductors. This is done by deriving effective low energy Hamiltonians correct to second order in the copper-oxygen hybridisation. Only hole doping is considered. When Cu2+ to Cu3+ fluctuations dominate we derive an effective one-band model of `Zhang-Rice' singlets with a nearest neighbour repulsion between...
Source: http://arxiv.org/abs/cond-mat/9407065v1
Arxiv.org
by Johan Bijnens
texts

eye 12

favorite 0

comment 0

The class of phenomenological Lagrangians used for light constituent quarks is discussed. The Nambu-Jona-Lasinio model is then argued to be a good phenomenological choice and the quality of its prediction in the purely hadronic sector including several relations between parameters illustrated. Then we use these models to calculate nonleptonic matrix elements. The $\pi^+-\pi^0$ mass difference and the $B_K$ parameter, relevant in $K^0-\overline{K}^0$ mixing, are treated in more detail.
Source: http://arxiv.org/abs/hep-ph/9411420v1
Arxiv.org
texts

eye 13

favorite 0

comment 0

We review the subject of CP violation in the $B$ meson system within the Standard Model of CP violation, which is based on a complex phase in the Cabibbo-Kobayashi-Maskawa (CKM) matrix. Three kinds of CP nonconservation are studied: In $B^0-\Bbar$ mixing, in mixed neutral $B$ decays to states which are common decay products of $B^0$ and $\Bbar$ and in direct decays of charged $B$ mesons. Measurements of certain CP asymmetries are shown to determine the three angles of the CKM unitarity...
Source: http://arxiv.org/abs/hep-ph/9411385v1
Arxiv.org
by S. Weber; M. Kachelriess; M. Unkelbach; H. M. Hofmann
texts

eye 13

favorite 0

comment 0

Longitudinal and transverse form factors are calculated for the transition into the low lying excited T=0 and T=1 states of 6Li in the framework of the resonating group model. All form factors are reproduced simultaneously using three cluster-wavefunctions. Meson exchange currents yield only minor corrections and do not lead to any specific structures at large momentum transfers.
Source: http://arxiv.org/abs/nucl-th/9407013v1
Arxiv.org
by Jnanadeva Maharana; Lambodhar P. Singh
texts

eye 11

favorite 0

comment 0

We have presented canonical and path integral formulations of a theory of loops and closed strings with the matter field quanta transforming in the adjoint representation of the SU(N) gauge group. The physical processes arising out of the interactions of loops and closed strings are discussed.
Source: http://arxiv.org/abs/hep-th/9401157v1
Arxiv.org
texts

eye 10

favorite 0

comment 0

We address the possibility of false vacuum decay in $N=1$ supergravity theories, including those corresponding to superstring vacua. By establishing a Bogomol'nyi bound for the energy density stored in the domain wall of the $O(4)$ invariant bubble, we show that supersymmetric vacua remain absolutely stable against false vacuum decay into another supersymmetric vacuum, including those from a Minkowski to an anti-deSitter (AdS) one. As a consequence, there are no compact static spherical domain...
Source: http://arxiv.org/abs/hep-th/9210006v1
Arxiv.org
texts

eye 12

favorite 0

comment 0

In this paper we construct a new quantum double by endowing the l-state bosonalgebra with a non-trivial Hopf algebra structure,which is not a q-deformation of the Lie algebra or superalgebra.The universal R-matrix for the Yang-Baxter equation associated with this new quantum group structure is obtained explicitly.By building the representations of this quantum double,we get some R-matrices ,which can result in new representations of the braid group.
Source: http://arxiv.org/abs/hep-th/9210148v1
Arxiv.org
by Fong Liu; Gene F. Mazenko
texts

eye 11

favorite 0

comment 0

The order parameter correlation function of the nonconserved, continuum $q$-state clock model is evaluated in the asymptotic scaling limit, during the phase ordering process after a temperature quench. The short distance behavior of the order parameter scaling function exhibits explicit crossover from that characteristic of the Ising universality class to that of the $O(2)$ model.
Source: http://arxiv.org/abs/cond-mat/9210009v1
Arxiv.org
by Cosmo Lupo; Vittorio Giovannetti; Stefano Mancini
texts

eye 36

favorite 0

comment 0

With increasing communication rates via quantum channels, memory effects become unavoidable whenever the use rate of the channel is comparable to the typical relaxation time of the channel environment. We introduce a model of a bosonic memory channel, describing correlated noise effects in quantum-optical processes via attenuating or amplifying media. To study such a channel model, we make use of a proper set of collective field variables, which allows us to unravel the memory effects, mapping...
Source: http://arxiv.org/abs/1005.2878v2
Arxiv.org
by Stefan S. Natu; Erich J. Mueller
texts

eye 44

favorite 0

comment 0

We model the dynamics of two species of bosonic atoms trapped in an optical lattice within the Mott regime by mapping the system onto a spin model. A field gradient breaks the cloud into two domains. We study how the domain wall evolves under adiabatic and diabatic changes of this gradient. We determine the timescales for adiabaticity, and study how temperature evolves for slow ramps. We show that after large, sudden changes of the field gradient, the system does not equilibrate on typical...
Source: http://arxiv.org/abs/1005.3090v2
Arxiv.org
by Freddie Withers; Marc Dubois; Alexander K. Savchenko
texts

eye 77

favorite 0

comment 0

We have fabricated transistor structures using fluorinated single-layer graphene flakes and studied their electronic properties at different temperatures. Compared with pristine graphene, fluorinated graphene has very large and strongly temperature dependent resistance in the electro-neutrality region. We show that fluorination creates a mobility gap in graphene's spectrum where electron transport takes place via localised electron states.
Source: http://arxiv.org/abs/1005.3474v3
Arxiv.org
by Eiichi Bannai; Etsuko Bannai; Junichi Shigezumi
texts

eye 82

favorite 0

comment 0

We give a new example of Euclidean tight 6-design in $\mathbb R^{22}$.
Source: http://arxiv.org/abs/1005.4987v2
Arxiv.org
texts

eye 11

favorite 0

comment 0

It is shown that the single particle band motion along the $c$ axis is harmful for superconductivity. Variation of $T_c$ with $c$ axis hopping parameter is shown for both the conventional planar superconductors and for interlayer pair tunneling mechanism of Wheatley Hsu and Anderson(WHA).Effect of out of plane magnetic impurity substitution is shown to suppres $T_c$ more for conventional superconductors whereas there is very sharp decrease of $T_c$ in the WHA mechanism at larger concentrations.
Source: http://arxiv.org/abs/cond-mat/9407010v1
Arxiv.org
by Shwetabh Singh
texts

eye 60

favorite 0

comment 0

Cosmological models involving shear and rotation are considered, first in the General Relat ivistic and then in the Newtonian framework with the aim of investigating singularities in them by using numerical and analytical techniques. The dynamics of these rotating models ar e studied. It is shown that singularities are unavoidable in such models and that the centr ifugal force arising due to rotation can never overcome the gravitational and shearing forc e over a length of time.
Source: http://arxiv.org/abs/astro-ph/9910239v1
Arxiv.org
by Manabu Takahashi; Jun-ichi Igarashi; Kunitomo Hirai
texts

eye 102

favorite 0

comment 0

Using ab-initio band structure calculation based on the local density approximation, Cr K-edge resonant X-ray magnetic scattering spectra are analyzed in the spin density wave (SDW) state of chromium. We perform band structure calculation, assuming an ideal bcc lattice structure with the lattice constant observed at the spin-flip temperature T_{SF} and a commensurate SDW state with the propagation vector close to the observed value at T_{SF}. Taking account of the spin-orbit interaction, we...
Source: http://arxiv.org/abs/cond-mat/0406576v1
Arxiv.org
by Paul Anderson; Henrik Jeldtoft Jensen; L. P. Oliveira; Paolo Sibani
texts

eye 68

favorite 0

comment 0

What features characterise complex system dynamics? Power laws and scale invariance of fluctuations are often taken as the hallmarks of complexity, drawing on analogies with equilibrium critical phenomena[1-3]. Here we argue that slow, directed dynamics, during which the system's properties change significantly, is fundamental. The underlying dynamics is related to a slow, decelerating but spasmodic release of an intrinsic strain or tension. Time series of a number of appropriate observables...
Source: http://arxiv.org/abs/cond-mat/0406689v1
Arxiv.org
by Anthony W. Thomas; Derek B. Leinweber; Ross D. Young
texts

eye 33

favorite 0

comment 0

We provide an overview of recent work exploring the quark-mass dependence of hadronic observables and the associated role of chiral nonanalytic behavior due to the meson-cloud of hadrons. In particular, we address an issue of great current interest, namely the degree of model independence of results obtained through a controlled extrapolation of lattice QCD simulation results. Physical insights gained from this research are highlighted. We emphasize how chiral effective field theory formulated...
Source: http://arxiv.org/abs/hep-lat/0406004v1
Arxiv.org
by Brian Billeter; Carleton DeTar; James Osborn
texts

eye 29

favorite 0

comment 0

The topological susceptibility of the vacuum in quantum chromodynamics has been simulated numerically using the Asqtad improved staggered fermion formalism. At nonzero lattice spacing the residual fermion doublers (fermion ``tastes'') in the staggered fermion formalism give contributions to the susceptibility that deviate from conventional continuum chiral perturbation theory. In this brief report we estimate the taste-breaking artifact and compare it with results of recent simulations, finding...
Source: http://arxiv.org/abs/hep-lat/0406032v1
Arxiv.org
by V. Bardek; S. Meljanac; A. Perica
texts

eye 39

favorite 0

comment 0

We consider the generalized momentum-depending quon algebra in a dynamically evolving curved spacetime and perform a type of analysis similar to that of J.W.Goodison and D.J.Toms. We find that, at least in principle, all kinds of statistics may occur in some regions, i.e. phases in momentum space, depending on Bogoliubov coefficients determined by a specific dynamical model.
Source: http://arxiv.org/abs/hep-th/9401128v1
Arxiv.org
texts

eye 89

favorite 0

comment 0

Subsingular vectors of the N=2 superconformal algebras were discovered, and examples given, in 1996. Shortly afterwards Semikhatov and Tipunin claimed to have obtained a complete classification of the N=2 subsingular vectors in the paper `The Structure of Verma Modules over the N=2 Superconformal algebra', hep-th/9704111, published in CMP 195 (1998) 129. Surprisingly, the only explicit examples of N=2 subsingular vectors known at that time did not fit into their classification. All the results...
Source: http://arxiv.org/abs/hep-th/9910121v1
Arxiv.org
by Tamas Hauer; Amer Iqbal
texts

eye 76

favorite 0

comment 0

A map between string junctions in the affine 7-brane backgrounds and vector bundles on del Pezzo surfaces is constructed using mirror symmetry. It is shown that the lattice of string junctions with support on an affine 7-brane configuration is isomorphic to the K-theory group of the corresponding del Pezzo surface. This isomorphism allows us to construct a map between the states of the N=2, D=4 theories with E_N global symmetry realized in two different ways in Type IIB and Type IIA string...
Source: http://arxiv.org/abs/hep-th/9910054v2
Arxiv.org
by Christopher Genovese; Larry Wasserman
texts

eye 73

favorite 0

comment 0

This paper extends the theory of false discovery rates (FDR) pioneered by Benjamini and Hochberg [J. Roy. Statist. Soc. Ser. B 57 (1995) 289-300]. We develop a framework in which the False Discovery Proportion (FDP)--the number of false rejections divided by the number of rejections--is treated as a stochastic process. After obtaining the limiting distribution of the process, we demonstrate the validity of a class of procedures for controlling the False Discovery Rate (the expected FDP). We...
Source: http://arxiv.org/abs/math/0406519v1
Arxiv.org
by Marcelo Lanzilotta; Octavio Mendoza; Corina Sáenz
texts

eye 32

favorite 0

comment 0

Let $\Gamma$ and $\Lambda$ be artin algebras such that $\Gamma$ is a split-by-nilpotent extension of $\Lambda$ by a two sided ideal $I$ of $\Gamma.$ Consider the so-called change of rings functors $G:={}_\Gamma\Gamma_\Lambda\otimes_\Lambda -$ and $F:={}_\Lambda \Lambda_\Gamma\otimes_\Gamma -.$ In this paper, we find the necessary and sufficient conditions under which a stratifying system $(\Theta,\leq)$ in $\modu\Lambda$ can be lifted to a stratifying system $(G\Theta,\leq)$ in...
Source: http://arxiv.org/abs/1304.5289v1
Arxiv.org
by Todor V. Veltchev; Sava Donkov; Ralf S. Klessen
texts

eye 35

favorite 0

comment 0

The statistical approach for derivation of the clump mass function (ClMF) developed by Donkov, Veltchev & Klessen is put to observational test through comparison with mass distributions of clumps from molecular emission and dust continuum maps of Galactic cloud complexes, obtained by various authors. The results indicate gravitational boundedness of the dominant clump population, with or without taking into account the contribution of their thermal and magnetic energy. The ClMF can be...
Source: http://arxiv.org/abs/1304.5902v2
Arxiv.org
texts

eye 54

favorite 0

comment 0

The drawdown process $Y=\bar{X}-X$ of an one-dimensional regular diffusion process $X$ is given by $X$ reflected at its running maximum $\bar{X}$. The drawdown process $\hat{Y}=X-\ul{X}$ is given by $X$ reflected at its running minimum $\ul{X}$. In this paper we calculate the probability of the event $\{\sigma_a 0$, where $\sigma_a$ and $\hat{\sigma}_b$ respectively denote the first passage times of $Y$ and $\hat{Y}$ to $a$ and $b$, and $\mathbf{e}_q$ is an exponential random variable which is...
Source: http://arxiv.org/abs/1304.8093v1
Arxiv.org
texts

eye 36

favorite 0

comment 0

We show that germs of local real-analytic CR automorphisms of a real-analytic hypersurface $M$ in $\C^2$ at a point $p\in M$ are uniquely determined by their jets of some finite order at $p$ if and only if $M$ is not Levi-flat near $p$. This seems to be the first necessary and sufficient result on finite jet determination and the first result of this kind in the infinite type case. If $M$ is of finite type at $p$, we prove a stronger assertion: the local real-analytic CR automorphisms of $M$...
Source: http://arxiv.org/abs/math/0107013v1
Arxiv.org
texts

eye 56

favorite 0

comment 0

In this contribution to the proceedings of the 68eme Rencontre entre Physiciens Theoriciens et Mathematiciens on Deformation Quantization I shall report on some recent joint work with Henrique Bursztyn on the representation theory of *-algebras arising from deformation quantization as I presented this in my talk.
Source: http://arxiv.org/abs/math/0107112v2
Arxiv.org
texts

eye 67

favorite 0

comment 0

We show that a totally geodesic submanifold of a symmetric space satisfying certain conditions admits an extension to a minimal submanifold of dimension one higher, and we apply this result to construct new examples of complete embedded minimal submanifolds in simply connected noncompact globally symmetric spaces.
Source: http://arxiv.org/abs/math/0107093v1
Arxiv.org
by Scott C. Dudley; Mario A. Serna
texts

eye 73

favorite 0

comment 0

A spaceship with one thruster producing a constant magnitude force is analyzed for various initial conditions. This elementary problem, with one object acted upon by one force, has value as a challenge to one's physical intuition and in demonstrating the benefits and limitations of dimensional analysis. In addition, the problem can serve to introduce a student to special functions, provide a mechanical model for Fresnel integrals and the associated Cornu spiral, or be used as an example in a...
Source: http://arxiv.org/abs/physics/0406150v1
Arxiv.org
by J. A. Caballero; V. J. S. Bejar; R. Rebolo; M. R. Zapatero Osorio
texts

eye 65

favorite 0

comment 0

We have carried out multi-epoch, time-series differential I-band photometry of a large sample of objects in the south-east region of the young (~3 Myr), nearby (~350 pc) sigma Orionis open cluster. A field of ~1000 arcmin^2 was monitored during four nights over a period of two years. Using this dataset, we have studied the photometric variability of twenty-eight brown dwarf cluster candidates with masses ranging from the stellar-substellar boundary down to the planetary-mass domain. We have...
Source: http://arxiv.org/abs/astro-ph/0406341v1
Arxiv.org
texts

eye 51

favorite 0

comment 0

In this talk, I review some recent work on cosmic microwave background (CMB) anisotropies in an open universe. I emphasize that the observed CMB anisotropies are still consistent with a low value of $\Omega$, and I address the question of whether future CMB measurements will be able to provide information on the geometry of the Universe.
Source: http://arxiv.org/abs/astro-ph/9407062v1
Arxiv.org
by P. Nalbach; O. Terzidis; K. Topp; A. Wuerger
texts

eye 58

favorite 0

comment 0

We study the dynamic response of a [111] quantum impurity, such as lithium or cyanide in alkali halides, with respect to an external field coupling to the elastic quadrupole moment. Because of the particular level structure of a eight-state system on a cubic site, the elastic response function shows a biexponential relaxation feature and a van Vleck type contribution with a resonance frequency that is twice the tunnel frequency $\Delta/\hbar$. This basically differs from the dielectric response...
Source: http://arxiv.org/abs/cond-mat/0009325v1
Arxiv.org
texts

eye 86

favorite 0

comment 0

We develop a polymer expansion with large/small field conditions for the mean resolvent of a weakly disordered system. Then we show that we can apply our result to a two-dimensional model, for energies outside the unperturbed spectrum or in the free spectrum provided the potential has an infra-red cut-off. This leads to an asymptotic expansion for the density of states. We believe this is an important first step towards a rigourous analysis of the density of states in the free spectrum of a...
Source: http://arxiv.org/abs/cond-mat/9702111v1
Arxiv.org
texts

eye 48

favorite 0

comment 0

We present the results of a search for doubly-charged Higgs bosons (H+/-+/-) decaying to dileptons using ~240/pb of ppbar collision data collected by the CDF II experiment at the Fermilab Tevatron. In our search region, given by same-sign dilepton mass m_ll' > 80 GeV/c^2 (100 GeV/c^2 for dielectron channel), we observe no evidence for doubly-charged Higgs production. We set limits on sigma (ppbar --> H++H-- --> l+l+l-l-) as a function of the mass of the doubly-charged Higgs boson and...
Source: http://arxiv.org/abs/hep-ex/0406073v1
Arxiv.org
by The Belle Collaboration; F. J. Ronga
texts

eye 39

favorite 0

comment 0

We report measurements of time dependent decay rates for $B^0 \to D^{(*)-}\pi^+$ decays and extraction of CP violation parameters that depend on $\phi_3$. Using fully reconstructed $D^{(*)}\pi$ events and partially reconstructed $D^{*}\pi$ events from a data sample that contains 386 million $B\bar{B}$ pairs that was collected near the $\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider, we obtain the CP violation parameters $S^+ (D^{(*)}\pi)$ and...
Source: http://arxiv.org/abs/hep-ex/0604013v1
Arxiv.org
by Fayyazuddin
texts

eye 29

favorite 0

comment 0

Isospin analysis has been used to constrain the CP-asymmetries in B -> pi pi decays. In particular correlation between a weak phase \theta and a strong phase \delta is obtained. Further using the experimental values for the CP-average branching ratios, the following bounds on direct CP-asymmetries are obtained: -0.35+/- 0.22= < C_{\pi ^+\pi^-}\leq 0; C_{\pi ^0\pi ^0}=-(2.4\pm 1.0) C_{\pi ^+\pi ^-}. Constraints on mixing induced CP-asymmetries are also discussed.
Source: http://arxiv.org/abs/hep-ph/0406130v2
Arxiv.org
by Takehiko Asaka; Shuntaro Nakamura; Masahiro Yamaguchi
texts

eye 53

favorite 0

comment 0

Cosmological issues of the gravitino production by the decay of a heavy scalar field $X$ are examined, assuming that the damped coherent oscillation of the scalar once dominates the energy of the universe. The coupling of the scalar field to a gravitino pair is estimated both in spontaneous and explicit supersymmetry breaking scenarios, with the result that it is proportional to the vacuum expectation value of the scalar field in general. Cosmological constraints depend on whether the gravitino...
Source: http://arxiv.org/abs/hep-ph/0604132v1
Arxiv.org
by Cedric Weber; Kristjan Haule; Gabriel Kotliar
texts

eye 42

favorite 0

comment 0

High temperature superconductivity was achieved by introducing holes in a parent compound consisting of copper oxide layers separated by spacer layers. It is possible to dope some of the parent compounds with electrons, and their physical properties are bearing some similarities but also significant differences from the hole doped counterparts. Here, we use a recently developed first principles method, to study the electron doped cuprates and elucidate the deep physical reasons why their...
Source: http://arxiv.org/abs/1005.3095v1