December 2006 arXiv papers — page 10
Showing 901–1,000 of 4,461 papers
Bishwaranjan Bhattacharjee, Vuk Ercegovac, Joseph Glider, Richard Golding
ably successful in building a large market and adapting to the changes of the last three decades, its impact on the broader market of information management is surprisingly limited. If we were to design an information management system from scratch, based upon today's requirements and hardware capabilities, would it look anything like today's database system
Daniel Gyllstrom, Eugene Wu, Hee-Jin Chae, Yanlei Diao
RFID technology is gaining adoption on an increasing scale for tracking and monitoring purposes. Wide deployments of RFID devices will soon generate an unprecedented volume of data. Emerging applications require the RFID data to be filtered and correlated for complex pattern detection and transformed to events that provide meaningful, actionable information
Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref
Biologists are increasingly using databases for storing and managing their data. Biological databases typically consist of a mixture of raw data, metadata, sequences, annotations, and related data obtained from various sources. Current database technology lacks several functionalities that are needed by biological databases. In this paper, we introduce bdbms
Petr R. Ivankov, Nikolay P. Ivankov
A framework for virtual reality of engineering objects has been developed. This framework may simulate different equipment related to virtual reality. Framework supports 6D dynamics, ordinary differential equations, finite formulas, vector and matrix operations. The framework also supports embedding of external software.
Emmanuel J. Candes, Paige A. Randall
This paper discusses a stylized communications problem where one wishes to transmit a real-valued signal x in R^n (a block of n pieces of information) to a remote receiver. We ask whether it is possible to transmit this information reliably when a fraction of the transmitted codeword is corrupted by arbitrary gross errors, and when in addition, all the entri
Joerg Wagner, Boris Rankov, Armin Wittneben
In this correspondence the cumulants of the mutual information of the flat Rayleigh fading amplify-and-forward MIMO relay channel without direct link between source and destination are derived in the large array limit. The analysis is based on the replica trick and covers both spatially independent and correlated fading in the first and the second hop, while
Stefan Funke, Soeren Laue, Zvi Lotker, Rouven Naujoks
A fundamental class of problems in wireless communication is concerned with the assignment of suitable transmission powers to wireless devices/stations such that the resulting communication graph satisfies certain desired properties and the overall energy consumed is minimized. Many concrete communication tasks in a wireless network like broadcast, multicast
Sujay Sanghavi, Bruce Hajek, Laurent Massoulie
This paper investigates the dissemination of multiple pieces of information in large networks where users contact each other in a random uncoordinated manner, and users upload one piece per unit time. The underlying motivation is the design and analysis of piece selection protocols for peer-to-peer networks which disseminate files by dividing them into piece
Statistical Mechanics of On-line Learning when a Moving Teacher Goes around an Unlearnable True Teacher
cs.LGMasahiro Urakami, Seiji Miyoshi, Masato Okada
In the framework of on-line learning, a learning machine might move around a teacher due to the differences in structures or output functions between the teacher and the learning machine. In this paper we analyze the generalization performance of a new student supervised by a moving machine. A model composed of a fixed true teacher, a moving teacher, and a s
C. A. Marianetti, K. Haule, O. Parcollet
The cobaltates have demonstrated a wide variety complex behavior. The Na rich region of the phase diagram displays various degrees of anomalous behavior, such as Curie-Weiss behavior near a band insulator\cite{Foo:2004}, charge disproportionation\cite{Mukhamedshin:2005}, and non-Fermi-liquid behavior in the resistivity\cite{Foo:2004}. Alternatively, the Na p
Yongfeng Mei, Dominic J. Thurmer, Francesca Cavallo, Suwit Kiravittaya
we demonstrate a technology "Release and bond-back of layers (REBOLA)" that exploits the deterministic wrinkling of a semiconductor layer to create well-defined and versatile nanochannel networks. In linear networks, the periodicity of branch channels as a function of etch-width was analyzed and compared with theoretical calculations. A self-similar
Universality Constraints on Three-Body Recombination for Cold Atoms: from 4He to 133Cs
cond-mat.otherEric Braaten, Daekyoung Kang, Lucas Platter
For atoms with large scattering length, the dependence of the 3-body recombination rate on the collision energy is determined by the scattering length and the Efimov 3-body parameters and can be expressed in terms of universal functions of a single scaling variable. We use published results on the 3-body recombination rate for 4He atoms to constrain the univ
The roles of apex dipoles and field penetration in the physics of charged, field emitting, single-walled carbon nanotubes
cond-mat.mtrl-sciJie Peng, Zhibing Li, Chunshan He, Guihua Chen
A 1 $μ$m long, field emitting, (5,5) single-walled, carbon nanotube (SWCNT) closed with a fullerene cap, and a similar open nanotube with hydrogen-atom termination, have been simulated using the MNDO (Modified Neglect of Diatomic Overlap) quantum-mechanical method. Both contain about 80 000 atoms. It is found that field penetration and band-bending, and vari
R. A. Borzi, S. A. Grigera, J. Farrell, R. S. Perry
In principle, a complex assembly of strongly interacting electrons can self-organise into a wide variety of collective states, but relatively few such states have been identified in practice. We report that, in the close vicinity of a metamagnetic quantum critical point, high purity Sr3Ru2O7 possesses a large magnetoresistive anisotropy, consistent with the
Patrick Levi, Klaus Mecke
An analytic expression is derived for the distribution $G(\vec{R})$ of the end-to-end distance $\vec{R}$ of semiflexible polymers in external potentials to elucidate the effect of confinement on the mechanical and statistical properties of biomolecules. For parabolic confinement the result is exact whereas for realistic potentials a self-consistent ansatz is
D. V. Kolesnikov, V. A. Osipov
The electronic states of capped semi-infinite nanotubes are studied within the phenomenological gauge field-theory model. A single manifold for the description of both the nanotube and the cap region (considered as nearly a half of either Ih or I fullerene) is suggested. The wavefunctions and the density of states (DoS) are numerically calculated for both me
Gravitational Dynamics of an Infinite Shuffled Lattice: Particle Coarse-grainings, Non-linear Clustering and the Continuum Limit
cond-mat.stat-mechT. Baertschiger, M. Joyce, A. Gabrielli, F. Sylos Labini
We study the evolution under their self-gravity of infinite ``shuffled lattice'' particle distributions, focussing specifically on the comparison of this evolution with that of ``daughter'' particle distributions, defined by a simple coarse-graining procedure. We consider both the case that such coarse-grainings are performed (i) on the initi
A. Isacsson, J. M. Kinaret, R. Kaunisto
The RF-response of a three-terminal carbon nanotube resonator coupled to RF-transmission lines is studied by means of perturbation theory and direct numerical integration. We find three distinct oscillatory regimes, including one regime capable of exhibiting very large hysteresis loops in the frequency response. Considering a purely capacitive transduction,
Clear Experimental Signature of Charge-Orbital density wave in Nd$_{1-x}$Ca$_{1+x}$MnO$_{4}$:Heat Capacity and Magnetization study
cond-mat.str-elSher Alam, A. T. M. N. Islam, T. Nagai, M. Xu
Single Crystals of Nd$_{1-x}$Ca$_{1+x}$MnO$_{4}$ have been prepared by the traveling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In the current note we present direct evidence of charge-or
Yu. D. Fomin, Daan Frenkel, N. V. Gribova, V. N. Ryzhov
The comprehensive computer simulation study of the phase diagram of the repulsive step potential system in three dimensions is represented. We show that the system with a simple purely repulsive isotropic potential demonstrates a number of unusual features. The maxima and minima on the melting curve are found for some regions of potential parameters. It is s
Jean-Philippe Colombier, Patrick Combis, Florian Bonneau, Ronan Le Harzic
Ablation of Cu and Al targets has been performed with 170 fs laser pulses in the intensity range of 10^12-10^14 W/cm^2. We compare the measured removal depth with 1D hydrodynamic simulations. The electron-ion temperature decoupling is taken into account using the standard "two-temperature model". The influence of the early heat transfer by electronic
Heisenberg model on a space with negative curvature: topological spin textures on the pseudosphere
cond-mat.str-elL. R. A. Belo, N. M. Oliveira-Neto, W. A. Moura-Melo, A. R. Pereira
Heisenberg-like spins lying on the pseudosphere (a 2-dimensional infinite space with constant negative curvature) cannot give rise to stable soliton solutions. Only fractional solutions can be stabilized on this surface provided that at least a hole is incorporated. We also address the issue of `in-plane' vortices, in the XY regime. Interestingly, the en
O. Waldmann
The low-temperature excitations in the magnetic Keplerate molecule Fe30 as calculated by linear spin-wave theory (SWT), modified linear SWT, and spin-level mean-field theory (SLMFT) are compared to the recent inelastic neutron scattering results by Garlea et al. [Phys. Rev. B 73, 024414 (2006)]. SLMFT reproduces a part of the experimental spectrum rather wel
Spin Susceptibility Representation of the Pairing Interaction for the two-dimensional Hubbard Model
cond-mat.supr-conT. A. Maier, M. Jarrell, D. J. Scalapino
Using numerical dynamic cluster quantum Monte Carlo results, we study a simple approximation for the pairing interaction of a two-dimensional Hubbard model with an on-site Coulomb interaction $U$ equal to the bandwidth. We find that with an effective temperature dependent coupling $\Ub(T)$ and the numerically calculated spin susceptibility $χ(K-K')$, the
A. Harada, S. Akutagawa, Y. Miyamichi, H. Mukuda
We report on the superconducting (SC) properties of Y$_2$C$_3$ with a relatively high transition temperature $T_{\rm c}=15.7$ K investigated by $^{13}$C nuclear-magnetic-resonance (NMR) measurements under a magnetic field. The $^{13}$C Knight shift has revealed a significant decrease below $T_{\rm c}$, suggesting a spin-singlet superconductivity. From an ana
V. E. Manucharyan, E. Boaknin, M. Metcalfe, R. Vijay
A Josephson tunnel junction which is RF-driven near a dynamical bifurcation point can amplify quantum signals. The bifurcation point will exist robustly only if the electrodynamic environment of the junction meets certain criteria. In this article we develop a general formalism for dealing with the non-linear dynamics of Josephson junction embedded in an arb
Hyun Cheol Koo, Hyunjung Yi, Jae-Beom Ko, Joonyeon Chang
We demonstrate fully electrical detection of spin injection in InAs quantum wells. A spin polarized current is injected from a NiFe thin film to a two-dimensional electron gas (2DEG) made of InAs based epitaxial multi-layers. Injected spins accumulate and diffuse out in the 2DEG, and the spins are electrically detected by a neighboring NiFe electrode. The ob
Stable and unstable regimes in Bose-Fermi mixture with attraction between components
cond-mat.stat-mechA. M. Belemuk, S. -T. Chui, V. N. Ryzhov
A collapse of the trapped boson- fermion mixture with the attraction between bosons and fermions is investigated in the framework of the effective Hamiltonian for the Bose system. The properties of the $^{87}$Rb and $^{40}$K mixture are analyzed quantitatively at $T= 0$. We find numerically solutions of modified Gross- Pitaevskii equation which continuously
G. Jogesh Babu, Ashish Mahabal, S. G. Djorgovski, R. Williams
In astronomy multiple images are frequently obtained at the same position of the sky for follow-up co-addition as it helps one go deeper and look for fainter objects. With large scale panchromatic synoptic surveys becoming more common, image co-addition has become even more necessary as new observations start to get compared with co-added fiducial sky in rea
Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. V: Final Measurement for Fornax
astro-phSlawomir Piatek, Carlton Pryor, Paul Bristow, Edward W. Olszewski
The measured proper motion of Fornax, expressed in the equatorial coordinate system, is $(μ_α,μ_δ)=(47.6\pm 4.6,-36.0\pm 4.1)$ mas century$^{-1}$. This proper motion is a weighted mean of four independent measurements for three distinct fields. Each measurement uses a quasi-stellar object as a reference point. Removing the contribution of the motion of the S
M. J. Darnley, E. Kerins, A. Newsam, J. P. Duke
The Angstrom Project is undertaking an optical survey of stellar microlensing events across the bulge region of the Andromeda Galaxy (M31) using a distributed network of two-meter class telescopes. The Angstrom Project Alert System (APAS) has been developed to identify in real time candidate microlensing and transient events using data from the Liverpool and
Spitzer Observations of 3C Quasars and Radio Galaxies: Mid-Infrared Properties of Powerful Radio Sources
astro-phK. Cleary, C. R. Lawrence, J. A. Marshall, L. Hao
We have measured mid-infrared radiation from an orientation-unbiased sample of 3CRR galaxies and quasars at redshifts 0.4 < z < 1.2 with the IRS and MIPS instruments on the Spitzer Space Telescope. Powerful emission (L_24micron > 10^22.4 W/Hz/sr) was detected from all but one of the sources. We fit the Spitzer data as well as other measurements from the lite
Patrick A. Young, Chris L. Fryer
Theoretical nucleosynthetic yields from supernovae are sensitive to both the details of the progenitor star and the explosion calculation. We attempt to comprehensively identify the sources of uncertainties in these yields. In this paper we concentrate on the variations in yields from a single progenitor arising from common 1-dimensional methods of approxima
Albert P. Linnell, Paula Szkody, Boris Gansicke, Knox S. Long
We use analysis results from a low state of the VY Sculptoris system MV Lyrae, considered in an earlier paper (Hoard et al., 2004, ApJ, 604, 346), to study archival IUE spectra taken during an intermediate state and a HST spectrum taken during a high state. The intermediate state spectrum can be best fit by an isothermal accretion disk extending half way to
Bradley C. Whitmore
Large numbers of young stars are formed in merging galaxies, such as the Antennae galaxies. Most of these stars are formed in compact star clusters (i.e., super star clusters), which have been the focus of a large number of studies. However, an increasing number of projects are beginning to focus on the individual stars as well. In this contribution, we exam
Roberto Aloisio
Neutrinos are the best candidates to test the extreme Universe and ideas beyond the Standard Model of particle Physics. Once produced, neutrinos do not suffer any kind of attenuation by intervening radiation fields like the Cosmic Microwave Background and are not affected by magnetic fields. In this sense neutrinos are useful messengers from the far and youn
R. Cameron, M. Schuessler
We study the origin of the predictive skill of some methods to forecast the strength of solar activity cycles. A simple flux transport model for the azimuthally averaged radial magnetic field at the solar surface is used, which contains a source term describing the emergence of new flux based on observational sunspot data. We consider the magnetic flux diffu
An Illustration of Modeling Cataclysmic Variables: HST, FUSE, SDSS Spectra of SDSSJ080908.39+381406.2
astro-phAlbert P. Linnell, D. W. Hoard, Paula Szkody, Knox S. Long
We use FUSE, HST, and SDSS spectra of the cataclysmic variable SDSSJ0809 to illustrate procedures for calculating and testing system models. Our final model has an accretion disk temperature profile similar to the SW Sextantis profile determined from tomographic reconstruction.
Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting observed SEDs using a large grid of pre-computed models
astro-phThomas P. Robitaille, Barbara A. Whitney, Remy Indebetouw, Kenneth Wood
We present a method to analyze the spectral energy distributions (SEDs) of young stellar objects (YSOs). Our approach is to fit data with pre-computed 2-D radiation transfer models spanning a large region of parameter space. This allows us to determine not only a single set of physical parameter values but the entire range of values consistent with the multi
The Influence of External UV Radiation Field on Primordial Gas Clouds: Formulation of the Problem
astro-phJaroslaw Stasielak, Slawomir Stachniewicz, Marek Kutschera
Our goal is to study the effects of the UV radiation from the first stars, quasars and decays of the hypothetical Super Heavy Dark Matter (SHDM) particles on the formation of primordial bound objects in the Universe. We trace the evolution of a spherically symmetric density perturbation in the Lambda Cold Dark Matter ($Λ$CDM) and MOND models, solving the fre
V. Suleimanov, K. Werner
Model atmospheres of isolated neutron stars with low magnetic field are calculated with Compton scattering taking into account. Models with effective temperatures 1, 3 and 5 MK, with two values of surface gravity log(g)g = 13.9 and 14.3), and different chemical compositions are calculated. Radiation spectra computed with Compton scattering are softer than th
D. Leahy, S. Morsink, C. Cadeau
Raytracing computations for light emitted from the surface of a rapidly rotating neutron star are carried out in order to construct light curves for accreting millisecond pulsars. These calculations are for realistic models of rapidly rotating neutron stars which take into account both the correct exterior metric and the oblate shape of the star. We find tha
N. R. Ikhsanov, P. L. Biermann
Accretion of interstellar material by a magnetized, slowly rotating isolated neutron star is discussed. We show that the average persistent X-ray luminosity of these objects is unlikely to exceed 4x10^26 erg/s. They can also appear as X-ray bursters with the burst duration of ~30 minutes and repetition time of \~10^5 yr. This indicates that the number of the
R. Smits, D. Mitra, B. Stappers, J. Kuijpers
Here we present the results from an analysis of a multifrequency simultaneous observation of PSR B0031$-$07. We have constructed a geometrical model, based on an empirical relationship between height and frequency of emission, that reproduces many of the observed characteristics. The model suggests very low emission altitudes for this pulsar of only a few ki
G. I. Melikidze, J. Gil, A. Szary
We propose a model, which naturally explains an unusual thermal X-ray emission, observed from PSR J1119-6127. The model is based on the assumption that the pulsar magnetic field near the stellar surface differs significantly from the pure dipole field. We show that the structure and curvature of the field lines can be of the kind that allows the pair creatio
N. Bucciantini, T. A. Thompson, J. Arons, E. Quataert
We solve the time-dependent dynamics of axisymmetric, general relativistic MHD winds from rotating neutron stars. The mass loss rate is obtained self consistently as a solution of the MHD equations, subject to a finite thermal pressure at the stellar surface. Conditions are chosen to be representative of the neutrino driven phase in newly born magnetars, whi
Y. N. Istomin, T. V. Shabanova
It is shown that the slow glitches in the spin rate of the pulsar B1822-09 can be explained by the reconstruction of the neutron star shape, which is not matched with the star rotation axis. Owing to the evolution of the inclination angle, i.e. the angle between the rotation axis and the axis of the magnetic dipole, under the action of the braking torque, th
Ersin Gogus, M. Ali Alpar, Marat Gilfanov
The spin periods of the neutron stars in most Low Mass X-ray Binary (LMXB) systems still remain undetected. One of the models to explain the absence of coherent pulsations has been the suppression of the beamed signal by Compton scattering of X-ray photons by electrons in a surrounding corona. We point out that simultaneously with wiping out the pulsation si
C. R. Stark, D. A. Diver, A. A. da Costa
Electrostatic oscillations in cold electron-positron plasmas can be coupled to a propagating electromagnetic mode if the background magnetic field is inhomogeneous. Previous work considered this coupling in the quasi-linear regime, successfully simulating the electromagnetic mode. Here we present a stability analysis of the non-linear problem, perturbed from
The Hanle Effect in Atomic and Molecular Lines: A New Look at the Sun's Hidden Magnetism
astro-phJ. Trujillo Bueno, A. Asensio Ramos, N. Shchukina
This paper reviews some of the most recent advances in the application of the Hanle effect to solar physics, and how these developments are allowing us to explore the magnetism of the photospheric regions that look ``empty'' in solar magnetograms--that is, the Sun's ``hidden'' magnetism. In particular, we show how a joint analysis of the
P. C. Hsu, K. Hirotani, H. K. Chang
We investigate a pair creation cascade in the magnetosphere of a rapidly rotating neutron star. We solve the set of the Poisson equation for the electro-static potential and the Boltzmann equations for electrons, positrons, and gamma-ray photons simultaneously. In this paper, we first examine the time-dependent nature of particle accelerators by solving the
Computation of Neutron Star Surface Emission Spectra for Arbitrary Magnetic Field Directions without Diffusion Approximation
astro-phL. W. Yeh, G. T. Chen, H. K. Chang
To derive physical properties of the neutron star surface with observed spectra, a realistic model spectrum of neutron star surface emission is essential. Limited by computing resources, a full computation of the radiative transfer equations without the diffusion approximation has been conducted up to date only for the case of local magnetic fields being per
Power spectra of black holes and neutron stars as a probe of hydrodynamical structure of the source. Diffusion theory and its application to Cyg X-1 and Cyg X-2 X-ray observations
astro-phLev Titarchuk, Nikolai Shaposhnikov, Vadim Arefiev
We present a model of Fourier Power Density Spectrum (PDS) formation in accretion powered X-ray binary systems derived from the first principles of the diffusion theory. Timing properties of X-ray emission are considered to be a result of diffusive propagation of the driving perturbations in a bounded medium. We prove that the integrated power P_x of the res
Robi Banerjee, Ralph E. Pudritz
We present an investigation of massive star formation that results from the gravitational collapse of massive, magnetized molecular cloud cores. We investigate this by means of highly resolved, numerical simulations of initial magnetized Bonnor-Ebert-Spheres that undergo collapse and cooling. By comparing three different cases - an isothermal collapse, a col
Silvio A. Bonometto, Luciano Casarini, Loris P. L. Colombo, Roberto Mainini
We compare a large set of cosmologies with WMAP data, performing a fit based on a MCMC algorithm. Besides of LCDM models, we take dynamical DE models, where DE and DM are uncoupled or coupled, both in the case of constant coupling and in the case when coupling varies with suitable laws. DE however arises from a scalar field self-interacting through a SUGRA p
Norman Danner, James S. Royer
This paper investigates what is essentially a call-by-value version of PCF under a complexity-theoretically motivated type system. The programming formalism, ATR, has its first-order programs characterize the polynomial-time computable functions, and its second-order programs characterize the type-2 basic feasible functionals of Mehlhorn and of Cook and Urqu
Guenter Rote, Francisco Santos, Ileana Streinu
A pseudo-triangle is a simple polygon with three convex vertices, and a pseudo-triangulation is a face-to-face tiling of a planar region into pseudo-triangles. Pseudo-triangulations appear as data structures in computational geometry, as planar bar-and-joint frameworks in rigidity theory and as projections of locally convex surfaces. This survey of current l
Fa Wang, F. Y. Wu
It is well-known that exact enumerations of close-packed dimers can be carried out for two-dimensional lattices. While details of results are now known for most lattices, due to the unique nature of the lattice structure, there has been no complete analysis for the kagome lattice. Here we derive the close-form expression $(1/3) \ln (4 x y z)$ for the free en
CDF Collaboration
We present an analysis of angular distributions and correlations of the X(3872) particle in the exclusive decay mode X(3872)->J/psi pi+ pi- with J/psi->mu+ mu-. We use 780 pb -1 of data from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We derive constraints on spin, parity, and charge conjugation parity
Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits
astro-phJonathan J. Fortney, Mark S. Marley, Jason W. Barnes
To aid in the physical interpretation of planetary radii constrained through observations of transiting planets, or eventually direct detections, we compute model radii of pure hydrogen-helium, water, rock, and iron planets, along with various mixtures. Masses ranging from 0.01 Earth masses to 10 Jupiter masses at orbital distances of 0.02 to 10 AU are consi
V. K. Oikonomou, J. D. Vergados, Ch. C. Moustakidis
The event rates for the direct detection of a dark matter candidate, which is a Kaluza-Klein gauge boson, are evaluated for a number of nuclear targets. Realistic form factors as well as spin ME and response functions are employed.
John Ellis, Mario E. Gomez, Smaragda Lola
We study the possible magnitudes of CP and lepton-number-violating quantities in specific GUT models of massive neutrinos with different Abelian flavour groups, taking into account experimental constraints and requiring successful leptogenesis. We discuss SU(5) and flipped SU(5) models that are consistent with the present data on neutrino mixing and upper li
M. Schechter, P. C. E. Stamp
This paper has been withdrawn.
S. Krohns, P. Lunkenheimer, S. G. Ebbinghaus, A. Loidl
We present dielectric measurements of the colossal dielectric constant material CaCu3Ti4O12 extending up to 1.3 GHz also covering so far only rarely investigated single crystalline samples. Special emphasis is put on the second relaxation reported in several works on polycrystals, which we detect also in single crystals. For polycrystalline samples we provid
V. Koerting, P. Wölfle, J. Paaske
We consider a lateral double-dot system in the Coulomb blockade regime with a single spin-1/2 on each dot, mutually coupled by an anti-ferromagnetic exchange interaction. Each of the two dots is contacted by two leads. We demonstrate that the voltage across one of the dots will have a profound influence on the current passing through the other dot. Using Poo
Josef Pradler, Frank Daniel Steffen
Considering gravitino dark matter scenarios, we study constraints on the reheating temperature of inflation. We present the gauge-invariant result for the thermally produced gravitino yield to leading order in the Standard Model gauge couplings. Within the framework of the constrained minimal supersymmetric Standard Model (CMSSM), we find a maximum reheating
Fernando Rodriguez Villegas
The purpose of this short note is to give a proof of the following identity between (logarithmic) Mahler measures m(y^2+2xy+y-x^3-2x^2-x)=5/7*m(y^2+4xy+y-x^3+x^2) which is one of many examples that arise from the comparison of Mahler measures and special values of L-functions.
T. Heinemann, A. Nordlund, G. B. Scharmer, H. C. Spruit
We present results of numerical 3D MHD simulations with radiative energy transfer of fine structure in a small sunspot of about 4 Mm width. The simulations show the development of filamentary structures and flow patterns that are, except for the lengths of the filaments, very similar to those observed. The filamentary structures consist of gaps with reduced
Yoshiyasu Ishigami
We give an extension of a graph result by Alon and Shapira. And it affirmatively settles a question on property testing raised by them. All monotone hypergraph properties and all hereditary partite hypergraph properties are testable. Our proof is constructive and based on a new hypergraph regularity lemma.
Matrix elements of the complete set of ΔB = 2 and ΔC = 2 operators in heavy meson chiral perturbation theory
hep-latWilliam Detmold, C. -J. David Lin
Using heavy meson chiral perturbation theory, we consider the light quark-mass and spatial volume dependence of the matrix elements of ΔB=2 and ΔC=2 four-quark operators relevant for B^{0}_{(s)}{-}\bar{B}^{0}_{(s)} and D^{0}{-}\bar{D}^{0} mixing, and the B_{s} meson width difference. Our results for these matrix elements are obtained in the N_{f}=2+1 partial
Martin Beneke, Johannes Rohrer, Deshan Yang
We calculate the hard-scattering kernels relevant to the negative-helicity decay amplitude in B decays to two vector mesons in the framework of QCD factorisation. We then perform a comprehensive analysis of the 34 B->VV decays, including B_s decays and the complete set of polarisation observables. We find considerable uncertainties from weak annihilation and
Vivien Lecomte, Julien Tailleur
We present an algorithm to evaluate the large deviation functions associated to history-dependent observables. Instead of relying on a time discretisation procedure to approximate the dynamics, we provide a direct continuous-time algorithm, valuable for systems with multiple time scales, thus extending the work of Giardinà, Kurchan and Peliti (PRL 96, 120603
Tamas Hausel, Fernando Rodriguez-Villegas
We calculate the E-polynomials of certain twisted GL(n,C)-character varieties M_n of Riemann surfaces by counting points over finite fields using the character table of the finite group of Lie-type GL(n,F_q) and a theorem proved in the appendix by N. Katz. We deduce from this calculation several geometric results, for example, the value of the topological Eu
Fernando Rodriguez Villegas
This is a mostly expository note concerning the following question: How fast can we compute the value of an L-function at the center of the critical strip? It is the writeup of my talk at the Matrix Ensembles and L-Functions workshop at the Isaac Newton Institute for Mathematical Sciences in Cambridge, UK on July 2005.
Evgeny Kh. Akhmedov, Michele Maltoni, Alexei Yu. Smirnov
We develop a detailed and comprehensive description of neutrino oscillations driven by the 1-3 mixing in the matter of the Earth. The description is valid for the realistic (PREM) Earth density profile in the whole range of nadir angles and for neutrino energies above 1 GeV. It can be applied to oscillations of atmospheric and accelerator neutrinos. The resu
Forest S. Patton, Gregory D. Bothun
This article has been withdrawn by the author due to an impending publication of a much improved version in a paper journal.
L. Filipe Costa, Carlos A. R. Herdeiro
We propose a new approach to a physical analogy between General Relativity and Electromagnetism, based on tidal tensors of both theories. Using this approach we write a covariant form for the gravitational analogues of the Maxwell equations. The following realisations of the analogy are given. The first one matches linearised gravitational tidal tensors to e
J. A. Casas, A. Ibarra, F. Jimenez-Alburquerque
It is an experimental fact that the mass ratio for the two heavier neutrinos, h = m_3/m_2 < 6, is much smaller than the typical quark and lepton hierarchies, which are O(20-300). We have explored whether this peculiar pattern of neutrino masses can be a consequence of the peculiar way they are generated through a see-saw mechanism, determining 1) How the pre
D0 Collaboration, V. M. Abazov
The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron ppbar collider. Using a 0.9 fb^-1 dataset, we apply a multivariate analysis to separate signal from background and measure sigma(ppbar->tb+X,tqb+X) = 4.9 +- 1.4 pb. The probability to measure a cross section at this value or higher in the absence of
Fernando Rodriguez Villegas
We outline a general algorithm for computing an explicit model over a number field of any curve of genus 2 whose (unpolarized) Jacobian is isomorphic to the product of two elliptic curves with CM by the same order in an imaginary quadratic field. We give the details and some examples for the case where the order has prime discriminant and class number one
P. Rubin, CLEO Collaboration
We present a measurement of the branching fraction of invisible Upsilon(1S) decays, using 1.2 fb^{-1} of data collected at the Upsilon(2S) resonance with the CLEO III detector at CESR. After subtracting expected backgrounds from events that pass selection criteria for invisible Upsilon(1S) decay in Upsilon(2S) -> pi+ pi- Upsilon(1S), we deduce a 90% C.L. upp
Fernando Rodriguez Villegas
The goal of this note is to present a combinatorial mechanism for counting certain objects associated to a variety X defined over a finite field. The basic example is that of counting conjugacy classes in GL_n(F_q), where X is the multiplicative group.
T. Corbitt, Y. Chen, H. Mueller-Ebhardt, E. Innerhofer
We report on a stable optical trap suitable for a macroscopic mirror, wherein the dynamics of the mirror are fully dominated by radiation pressure. The technique employs two frequency-offset laser fields to simultaneously create a stiff optical restoring force and a viscous optical damping force. We show how these forces may be used to optically trap a free
S. H. Curnoe
Low energy collective angular momentum states of the Tb3+ ions in Tb2Ti2O7 are classified according to the irreducible representations of the octahedral point group. Degeneracy lifting due to the exchange interaction is discussed. Diffuse neutron scattering intensity patterns are calculated for each collective angular momentum state and the ground state is i
F. Castano Iglesias, C. Nastasescu, J. Vercruysse
We investigate functors between abelian categories having a left adjoint and a right adjoint that are \emph{similar} (these functors are called \emph{quasi-Frobenius functors}). We introduce the notion of a \emph{quasi-Frobenius bimodule} and give a characterization of these bimodules in terms of quasi-Frobenius functors. Some applications to corings and gra
S. Yi, T. Li, C. P. Sun
We investigate the quantum phases of polarized dipolar Bosons loaded into a two-dimensional square and three-dimensional cubic optical lattices. We show that the long-range and anisotropic nature of the dipole-dipole interaction induces a rich variety of quantum phases, including the supersolid and striped supersolid phases in 2D lattices, and the layered su
Universality in one dimensional orbital wave ordering in spinel and related compounds: an experimental perspective
cond-mat.str-elM. Croft, V. Kiryukhin, Y. Horibe, S-W. Cheong
Recent state-of-the-art crystallographic investigations of transition metal spinel compounds have revealed that the d- orbital charge carriers undergo ordering transitions with the formation of local "molecular bonding" units such as dimers in MgTi2O4, octomers in CuIr2S4, and heptamers in AlV2O4. Herein, we provide a unifying scheme involving one- d
Survival probability of a diffusing particle constrained by two moving, absorbing boundaries
cond-mat.stat-mechAlan J. Bray, Richard Smith
We calculate the exact asymptotic survival probability, Q, of a one-dimensional Brownian particle, initially located located at the point x in (-L,L), in the presence of two moving absorbing boundaries located at \pm(L+ct). The result is Q(y,λ) = \sum_{n=-\infty}^\infty (-1)^n \cosh(ny) \exp(-n^2λ), where y=cx/D, λ= cL/D and D is the diffusion constant of th
Christophe Real
It is shown how can be made the classification of all tensors constructed from the Riemann tensor that verify the conservation of gravitational energy momentum. More precisely we explain that there exists a unique tensor of degree n in the Riemann tensor and its contractions that verifies the conservation of energy. We show that this tensor, only because it
Marco Regis, Marco Serone, Piero Ullio
We show that a recently constructed five-dimensional (5D) model with gauge-Higgs unification and explicit Lorentz symmetry breaking in the bulk, provides a natural dark matter candidate. This is the lightest Kaluza-Klein particle odd under a certain discrete Z_2 symmetry, which has been introduced to improve the naturalness of the model, and resembles KK-par
Dead Zone Formation and Nonsteady Hyperaccretion in Collapsar Disks : A Possible Origin of Short-Term Variability in the Prompt Emission of Gamma-Ray Bursts
astro-phYouhei Masada, Norita Kawanaka, Takayoshi Sano, Kazunari Shibata
The central engine of gamma-ray bursts (GRBs) is believed to be a hot and dense disk with hyperaccretion onto a few solar-mass black hole. We investigate where the magnetorotational instability (MRI) actively operates in the hyperaccretion disk, which can cause angular momentum transport in the disk. The inner region of hyperaccretion disks can be neutrino o
Megumi Harada, Gregory D. Landweber
Let T be a compact torus and (M,ω) a Hamiltonian T-space. In a previous paper, the authors showed that the T-equivariant K-theory of the manifold M surjects onto the ordinary integral K-theory of the symplectic quotient M \mod T of M by T, under certain technical conditions on the moment map. In this paper, we use equivariant Morse theory to give a method fo
Victor S. Fadin, Roberto Fiore, Alessandro Papa
The ``non-Abelian'' part of the quark contribution to the BFKL kernel in the next-to-leading order (NLO) is found in the coordinate representation by direct transfer of the contribution from the momentum representation where it was calculated before. The results obtained are used for the examination of conformal properties of the NLO BFKL kernel and
Yu. V. Gaponov, V. V. Khruschov, S. V. Semenov
The recent experimental data on mixing angles for quarks and neutrino have been discussed. Quarks mixing angles are calculated in the phenomenological approach of Fritzsch-Scadron-Delbourgo-Rupp (FSDR approach) using mass values of light and heavy constituent quarks. The neutrino mixing angles have been calculated with the high degree of precision with the h
D. Epple, H. Reinhardt, W. Schleifenbaum
The Dyson-Schwinger equations arising from minimizing the vacuum energy density in the Hamiltonian approach to Yang-Mills theory in Coulomb gauge are solved numerically. A new solution is presented which gives rise to a strictly linearly rising static quark potential and whose existence was previously observed in the infrared analysis of the Dyson-Schwinger
Probing inflation with CMB polarization : weak lensing effect on the covariance of CMB spectra
astro-phJonathan Rocher, Karim Benabed, Francois Bouchet
CMB anisotropies are modified by the weak lensing effect of intervening large scale structures on the photon path from the last scattering surface to the observer. This has to be accounted for when observational data of sensitive experiments are used to constrain cosmological models. A common approximation to analyze the CMB angular power spectra is to inclu
Paul Bode, Jeremiah P. Ostriker, Jochen Weller, Laurie Shaw
Using the full, three-dimensional potential of galaxy cluster halos (drawn from an N-body simulation of the current, most favored cosmology), the distribution of the X-ray emitting gas is found by assuming a polytropic equation of state and hydrostatic equilibrium, with constraints from conservation of energy and pressure balance at the cluster boundary. The
All order epsilon-expansion of Gauss hypergeometric functions with integer and half/integer values of parameters
hep-thM. Yu. Kalmykov, B. F. L. Ward, S. Yost
It is proved that the Laurent expansion of the following Gauss hypergeometric functions, 2F1(I1+a*epsilon, I2+b*ep; I3+c*epsilon;z), 2F1(I1+a*epsilon, I2+b*epsilon;I3+1/2+c*epsilon;z), 2F1(I1+1/2+a*epsilon, I2+b*epsilon; I3+c*epsilon;z), 2F1(I1+1/2+a*epsilon, I2+b*epsilon; I3+1/2+c*epsilon;z), 2F1(I1+1/2+a*epsilon,I2+1/2+b*epsilon; I3+1/2+c*epsilon;z), where
João Faria Martins, Aleksandar Mikovic
We study the invariants of spin networks embedded in a three-dimensional manifold which are based on the path integral for SU(2) BF-Theory. These invariants appear naturally in Loop Quantum Gravity, and have been defined as spin-foam state sums. By using the Chain-Mail technique, we give a more general definition of these invariants, and show that the state-
M. R. Goad, K. L. Page, O. Godet, A. Beardmore
We report on the temporal and spectral characteristics of the early X-ray emission from the Gamma Ray Burst 051117A as observed by Swift. The superb quality of the early X-ray light-curve and spectra of this source, one of the brightest seen by the X-ray Telescope at such early times, allows an unprecedented look at the spectral and temporal evolution of the