March 2006 arXiv papers — page 35
Showing 3,401–3,500 of 4,608 papers
V. P. Gusynin, S. G. Sharapov, J. P. Carbotte
Recent experiments have proven that the quasiparticles in graphene obey a Dirac equation. Here we show that microwaves are an excellent probe of their unusual dynamics. When the chemical potential is small the intraband response can exhibit a cusp around zero frequency $Ω$ and this unusual lineshape changes to Drude-like by increasing the chemical potential
BCS-BEC crossover and quantum phase transition for 6Li and 40K atoms across Feshbach resonance
cond-mat.otherW. Yi, L. -M. Duan
We systematically study the BCS-BEC crossover and the quantum phase transition in ultracold 6Li and 40K atoms across a wide Feshbach resonance. The background scattering lengths for 6Li and 40K have opposite signs, which lead to very different behaviors for these two types of atoms. For 40K, both the two-body and the many-body calculations show that the syst
Ioannis Giannakis, Defu Hou, Mei Huang, Hai-cang Ren
We use the Ginzburg-Landau theory near the transition temperature in order to examine the behavior of an inhomogeneous superconductor in the presence of a magnetic field. We find that a transition from type I to type II superconductivity occurs. Furthermore we calculate the critical value of the mismatch and estimate the contributions of the fluctuations of
Comment on "Turbulent heat transport near critical points: Non-Boussinesq effects" (cond-mat/0601398)
cond-mat.otherXavier Chavanne, Philippe-Emmanuel P. -E. Roche, Benoît Chabaud, Bernard Hébral
In a recent preprint (cond-mat/0601398), D. Funfschilling and G. Ahlers describe a new effect, that they interpret as non-Boussinesq, in a convection cell working with ethane, near its critical point. They argue that such an effect could have spoiled the Chavanne {\it et al.} (Phys. Rev. Lett. {\bf 79} 3648, 1997) results, and not the Niemela {\it et al.} (N
M. F. Craciun, S. Rogge, A. F. Morpurgo
We have investigated the evolution of the temperature-dependent conductivity of electron-doped pentacene (PEN) thin films, in which the electron density is controlled by means of potassium (K) intercalation. We find that the conductivity is high and exhibit metallic temperature dependence in a broad range of concentrations up to approximately 1 K/PEN. At thi
Kimberley C. Hall, Michael E. Flatté
Fundamental physical properties limiting the performance of spin field effect transistors are compared to those of ordinary (charge-based) field effect transistors. Instead of raising and lowering a barrier to current flow these spin transistors use static spin-selective barriers and gate control of spin relaxation. The different origins of transistor action
J. Hemberger, F. Schrettle, A. Pimenov, P. Lunkenheimer
We report on structural, magnetic, dielectric, and thermodynamic properties of (Eu:Y)MnO3 for Y doping levels 0 <= x < 1. This system resembles the multiferroic perovskite manganites RMnO3 (with R= Gd, Dy, Tb) but without the interference of magnetic contributions of the 4f-ions. In addition, it offers the possibility to continuously tune the influence of th
T. R. S. Prasanna
A new method to determine electron correlation energy is described. This method is based on a better representation of the potential due to interacting electrons that is obtained by specifying both the average and standard deviation. The standard deviation is determined from a probabilistic interpretation of the Coulomb interaction between electrons. This le
Andrea Ferretti, Arrigo Calzolari, Benedetta Bonferroni, Rosa Di Felice
We report a theoretical scheme that enables the calculation of maximally localized Wannier functions in the formalism of projector-augmented-waves (PAW) which also includes the ultrasoft-pseudopotential (USPP) approach. We give a description of the basic underlying formalism and explicitly write all the required matrix elements from the common ingredients of
Quantum measurement of an electron in disordered potential: delocalization versus measurement voltages
cond-mat.mes-hallXue-Ning Hu, Xin-Qi Li
Quantum point contact (QPC), one of the typical mesoscopic transport devices, has been suggested to be an efficient detector for quantum measurement. In the context of two-state charge qubit, our previous studies showed that the QPC's measurement back-action cannot be described by the conventional Lindblad quantum master equation. In this work, we study
Joseph Maciejko, Jian Wang, Hong Guo
One of the most important problems in nanoelectronic device theory is to estimate how fast or how slow a quantum device can turn on/off a current. For an arbitrary noninteracting phase-coherent device scattering region connected to the outside world by leads, we have derived an exact solution for the nonequilibrium, nonlinear, and time-dependent current driv
Evidence for unconventional superconducting fluctuations in heavy-fermion compound CeNi2Ge2
cond-mat.str-elS. Kawasaki, T. Sada, T. Miyoshi, H. Kotegawa
We present evidence for unconventional superconducting fluctuations in a heavy-fermion compound CeNi$_2$Ge$_2$. The temperature dependence of the $^{73}$Ge nuclear-spin-lattice-relaxation rate $1/T_1$ indicates the development of magnetic correlations and the formation of a Fermi-liquid state at temperatures lower than $T_{\rm FL}=0.4$ K, where $1/T_1T$ is c
T. Scopigno, J. -B. Suck, R. Angelini, F. Albergamo
Using Inelastic X-ray Scattering we studied the collective dynamics of the glassy alloy Ni$_{33}$Zr$_{67}$ in the first pseudo Brillouin zone, an energy-momentum region still unexplored in metallic glasses. We determine key properties such as the momentum transfer dependence of the sound velocity and of the acoustic damping, discussing the results in the gen
C Godreche
The present work is an endeavour to determine analytically features of the stationary measure of a non-integrable zero-range process, and to investigate the possible existence of phase transitions for such a nonequilibrium model. The rates defining the model do not satisfy the constraints necessary for the stationary measure to be a product measure. Even in
Efim A. Brener, V. I. Marchenko
We consider periodic domain structures which appear due to the magnetoelastic interaction if the antiferromagnetic crystal is attached to an elastic substrate. The peculiar behavior of such structures in an external magnetic field is discussed. In particular, we find the magnetic field dependence of the equilibrium period and the concentrations of different
Enhancing the Superconducting Transition Temperature due to Strong-Coupling Effect under Antiferromagnetic Spin Fluctuations in CeRh1-xIrxIn5 : 115In-NQR Study
cond-mat.supr-conShinji Kawasaki, Mitsuharu Yashima, Yoichi Mugino, Hidekazu Mukuda
We report on systematic evolutions of antiferromagnetic (AFM) spin fluctuations and unconventional superconductivity (SC) in heavy-fermion (HF) compounds CeRh$_{1-x}$Ir$_{x}$In$_5$ via $^{115}$In nuclear-quadrupole-resonance (NQR) experiment. The measurements of nuclear spin-lattice relaxation rate $1/T_1$ have revealed the marked development of AFM spin flu
Sensitivity function and entropy increase rates for z-logistic map family at the edge of chaos
cond-mat.stat-mechAhmet Celikoglu, Ugur Tirnakli
It is well known that, for chaotic systems, the production of relevant entropy (Boltzmann-Gibbs) is always linear and the system has strong (exponential) sensitivity to initial conditions. In recent years, various numerical results indicate that basically the same type of behavior emerges at the edge of chaos if a specific generalization of the entropy and t
J. Lages, P. D. Sacramento
We study the influence of disorder on the vortex charge, both due to random pinning of the vortices and due to scattering off non-magnetic impurities. In the case when there are no impurities present, but the vortices are randomly distributed, the effect is very small, except when two or more vortices are close by. When impurities are present, they have a no
Guy Fayolle, Cyril Furtlehner
This study in centered on models accounting for stochastic deformations of sample paths of random walks, embedded either in $\mathbb{Z}^2$ or in $\mathbb{Z}^3$. These models are immersed in multi-type particle systems with exclusion. Starting from examples, we give necessary and sufficient conditions for the underlying Markov processes to be reversible, in w
Thomas Michael, Steffen Trimper, Michael Schulz
The Glauber model is reconsidered based on a quantum formulation of the Master equation. Unlike the conventional approach the temperature and the Ising energy are included from the beginning by introducing a Heisenberg-like picture of the second quantized operators. This method enables us to get an exact expression for the transition rate of a single flip-pr
G. Filatrella, N. F. Pedersen, K. Wiesenfeld
We propose a modification of the Kuramoto model to account for the effective change in the coupling constant among the oscillators, as suggested by some experiments on Josephson junction, laser arrays and mechanical systems, where the active elements are turned on one by one. The resulting model is analytically tractable and predicts that both first and seco
Test of cold denaturation mechanism for proteins as a function of water's structure
cond-mat.otherManuel I. Marques
In a recent paper [PRL 91, 138103 (2003)] a new mechanism to explain the cold denaturation of proteins, based on the loss of local low-density water structure, has been proposed. In the present paper this mechanism is tested by means of full atom numerical simulations. In good agreement with this proposal, cold denaturation resulting in the unfolded state wa
R. Rurali, V. R. Coluci, D. S. Galvão
We study by first-principles calculations the electro-mechanical response of carbon nanoscrolls. We show that although they present a very similar behavior to carbon nanotubes for what concerns the axial deformation sensitivity, they exhibit a radial response upon charge injection which is up to one order of magnitude larger. In association with their high s
Large magnetoresistance in La2/3Ca1/3MnO3 thin films induced by metal masked ion damage technique
cond-mat.mtrl-sciM. J. Zhang, J. Li, Z. H. Peng, D. N. Zheng
e have developed a simple process to obtain large magnetoresistance (MR) in perovskite manganite thin films by a combination of focused ion beam (FIB) milling and 120 keV H$_{2}^{+}$ ion implantation. Metal slits about 70 nm in width were printed by 30 kV focused Ga ion beam nanolithography on a 4 mm track, and the materials in these slits are then irradiate
Fulde-Ferrel-Larkin-Ovchinnikov Inhomogeneous Superconducting State and Phase Transitions Induced by Spin Accumulation in a Ferromagnet-$ d_{x^{2}-y^{2}}$-Wave Superconductor-Ferromagnet Tunnel Junction
cond-mat.supr-conBiao Jin, Gang Su, Qing-Rong Zheng
Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) inhomogeneous superconducting (SC) state, first- and second-order phase transitions, and quantum criticality induced by spin accumulation in a ferromagnet-$d_{x^{2}-y^{2}}$-wave superconductor-ferromagnet tunnel junction are theoretically predicted. A complex phase diagram in the temperature-bias voltage plane is determ
Spin Current and Current-Induced Spin Transfer Torque in Ferromagnet-Quantum Dot-Ferromagnet Coupled Systems
cond-mat.mes-hallHai-Feng Mu, Gang Su, Qing-Rong Zheng
Based on Keldysh's nonequilibrium Green function method, the spin-dependent transport properties in a ferromagnet-quantum dot (QD)-ferromagnet coupled system are investigated. It is shown the spin current shows quite different characteristics from its electrical counterpart, and by changing the relative orientation of both magnetizations, it can change i
Tao Li, Qiang-Hua Wang, Zheng-Yu Weng, Fan Yang
Based on a Gutzwiller projected BCS wavefunction, it is shown that a local S=1/2 moment is present around a vacancy site (zinc impurity) in a form of staggered magnetic moments, which is a direct consequence of the short-ranged resonating-valence-bond (RVB) pairing in the spin background.
L. -H Liang, Baowen Li
We study the size dependence of thermal conductivity in nanoscale semiconducting systems. An analytical formula including the surface scattering and the size confinement effects of phonon transport is derived. The theoretical formula gives good agreements with the existing experimental data for Si and GaAs nanowires and thin films.
Small-polaron coherent conduction in lightly doped ReTiO$_{3+ δ/2}$ (Re=La or Nd) thin films prepared by Pulsed Laser Deposition
cond-mat.str-elJ. Li, F. B. Wang, P. Wang, M. J. Zhang
LaTiO$_{3+δ/2}$, NdTiO$_{3+δ/2}$, and Nd$_{1-x}$Sr$_{x}$TiO$_{3+δ/2}$ thin films have been epitaxially grown on (100)SrTiO$_{3}$ and (100)LaAlO$_{3}$ single crystal substrates by using the pulsed laser deposition technique. The oxygen pressure during deposition has been carefully controlled to ensure that the films are lightly doped in the metal side near th
Yasuhiro Hatsugai
We propose to use quantized Berry phases as local order parameters of gapped quantum liquids, which are invariant under some anti-unitary operation. After presenting a general prescription, the scheme is applied for Heisenberg models with frustrations and two dimensional extended Su-Schrieffer-Heeger models associated with a random dimer covering. In each ph
Competition between d-wave superconductivity and antiferromagnetism in the 2D Hubbard model
cond-mat.str-elM. Capone, G. Kotliar
We study the competition of antiferromagnetism and d-wave superconductivity at zero-temperature in the two-dimensional Hubbard model using Cellular Dynamical Mean Field Theory. The interplay between the two phases depends strongly on the strength of the correlation. At strong coupling ($ U \ge 8t$) the two phases do not mix, and a first-order transition take
J. Geck, P. Wochner, S. Kiele, P. Reutler
We present a resonant x-ray scattering study of the octahedral tilt order between 50K and 310K in La_7/8Sr_1/8MnO_3. At the La L_II-edge the resonant (300) reflection probes cooperative tilts of the MnO_6-octahedra in this material, as verified by a model caclulation as well as a LDA+U study. The investigation of the octahedral tilts as a function of tempera
Luca Dall'Asta, Andrea Baronchelli, Alain Barrat, Vittorio Loreto
In this paper we analyze the effect of a non-trivial topology on the dynamics of the so-called Naming Game, a recently introduced model which addresses the issue of how shared conventions emerge spontaneously in a population of agents. We consider in particular the small-world topology and study the convergence towards the global agreement as a function of t
Azam Gholami, Jan Wilhelm, Erwin Frey
The entropic force exerted by the Brownian fluctuations of a grafted semiflexible polymer upon a rigid smooth wall are calculated both analytically and by Monte Carlo simulations. Such forces are thought to play an important role for several cellular phenomena, in particular, the physics of actin-polymerization-driven cell motility and movement of bacteria l
A. N. Gorban
We consider two basic types of coarse-graining: the Ehrenfests' coarse-graining and its extension to a general principle of non-equilibrium thermodynamics, and the coarse-graining based on uncertainty of dynamical models and Epsilon-motions (orbits). Non-technical discussion of basic notions and main coarse-graining theorems are presented: the theorem ab
Ultrafast laser excitation of spin waves by permanent modification of the exchange bias interaction in IrMn/Co
cond-mat.mtrl-sciKeoki A. Seu, Hailong Huang, Anne C. Reilly
This paper has been withdrawn by the authors due to a critical error discovered in Figures 1, 2 and 4.
Michael Köhl
Low temperatures are necessary for the observation of strongly correlated quantum phases of fermionic atoms in optical lattices. We analyze how the temperature of a Fermi gas is altered when the fermions are loaded into an optical lattice with an underlying harmonic confining potential and show how the temperature can be measured. The temperature of the atom
Density Functional Theory study of the low-energy electronic structures and properties of small gold clusters : Zigzag gold nanoclusters
cond-mat.otherPrashant K. Jain
Gold clusters Aun of size n = 2 to 12 atoms were studied by the density-functional theory with an ab-initio pseudopotential and a generalized gradient approximation. Geometry optimizations starting from a number of initial candidate geometries were performed for each cluster size, so as to determine a number of possible low-energy isomers for each size. Alon
Alejandro Mora, Thomas Rabbow, Peter J. Plath, Maria Haase
We present a unidimensional discrete solid-on-solid model evolving in time using a kinetic Monte Carlo method to simulate micro-structuring of kerfs on metallic surfaces by means of laser-induced jet-chemical etching. The precise control of the passivation layer achieved by this technique is responsible for the high resolution of the structures. However, wit
Zhang Gang, Baowen Li
We study the dependence of thermal conductivity of single walled nanotubes (SWNT) on chirality and isotope impurity by nonequilibrium molecular dynamics method with accurate potentials. It is found that, contrary to electronic conductivity, the thermal conductivity is insensitive to the chirality. The isotope impurity, however, can reduce the thermal conduct
R. D. Alexander, C. J. Clarke, J. E. Pringle
We present a new model for protoplanetary disc evolution. This model combines viscous evolution with photoevaporation of the disc, in a manner similar to Clarke, Gendrin & Sotomayor (2001). However in a companion paper (Alexander, Clarke & Pringle 2006a) we have shown that at late times such models must consider the effect of stellar radiation directly incid
R. D. Alexander, C. J. Clarke, J. E. Pringle
In this paper we consider the effect of the direct ionizing stellar radiation field on the evolution of protoplanetary discs subject to photoevaporative winds. We suggest that models which combine viscous evolution with photoevaporation of the disc (e.g. Clarke, Gendrin & Sotomayor 2001) incorrectly neglect the direct field after the inner disc has drained,
H. M. Araujo, D. Yu. Akimov, G. J. Alner, A. Bewick
We present results from a GEANT4-based Monte Carlo tool for end-to-end simulations of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a two-phase detector which measures both the scintillation light and the ionisation charge generated in liquid xenon by interacting particles and radiation. The software models the instrument response to radioactive backg
The distribution of current helicity at the solar surface at the beginning of the solar cycle
astro-phD. Sokoloff, S. D. Bao, N. Kleeorin, K. Kuzanyan
A fraction of solar active regions are observed to have current helicity of a sign that contradicts the polarity law for magnetic helicity; this law corresponds to the well-known Hale polarity law for sunspots. A significant excess of active regions with the "wrong" sign of helicity is seen to occur just at the beginning of the cycle. We compare thes
A. M. Hidalgo-Gamez
We have studied the spectral characteristics of the Diffuse Ionized Gas in two irregular galaxies with low metallicities and intermediate Star Formation Rates: ESO 245-G05 and Gr 8. The [OIII]/Hbeta in these galaxies is higher than in the DIG of spiral galaxies but not as high as in other irregular galaxies previously studied, such as IC 10 and NGC 6822. The
Hubble Space Telescope Near-Infrared Snapshot Survey of 3CR radio source counterparts at low redshift
astro-phJuan P. Madrid, Marco Chiaberge, David Floyd, William B. Sparks
We present newly acquired images of the near-infrared counterpart of 3CR radio sources. All the sources were selected to have a redshift of less than 0.3 to allow us to obtain the highest spatial resolution. The observations were carried out as a snapshot program using the Near-Infrared Camera and Multiobject Spectrograph (NICMOS) on-board the Hubble Space T
Keith A. Olive, Pearl Sandick
We consider the relic neutrino background produced by Population III stars coupled with a normal mode of star formation at lower redshift. The computation is performed in the framework of hierarchical structure formation and is based on cosmic star formation histories constrained to reproduce the observed star formation rate at redshift z \la 6, the observed
S. P. Goodwin, P. Kroupa, A. Goodman, A. Burkert
Almost all young stars are found in multiple systems. This suggests that protostellar cores almost always fragment into multiple objects. The observed properties of multiple systems such as their separation distribution and mass ratios provide strong constraints on star formation theories. We review the observed properties of young and old multiple systems a
Matt J. Jarvis, Caroline van Breuekeln, Bram P. Venemans, Richard J. Wilman
We present results from a new method of exploring the distant Universe. We use 3-D spectroscopy to sample a large cosmological volume at a time when the Universe was less than 3 billion years old to investigate the evolution of star-formation activity. Within this study we also discovered a high redshift type-II quasar which would not have been identified wi
Orientation dependency of broad-line widths in quasars and consequences for black-hole mass estimation
astro-phMatt J. Jarvis, Ross J. McLure
In this paper we report new evidence that measurements of the broad-line widths in quasars are dependent on the source orientation, consistent with the idea that the broad-line region is flattened or disc-like. This reinforces the view derived from radio-selected samples, where the radio-core dominance has been used as a measure of orientation. The results p
J. Miao, G. J. White, R. P. Nelson, M. A. Thompson
A three dimensional Smoothed Particle Hydrodynamical (SPH) model has been extended to study the radiative driven implosion effect of massive stars on the dynamical evolutions of surrounding molecular clouds. The new elements in the upgraded code are the inclusion of Lyman continuum in the incident radiation flux and the treatment of hydrogen ionisation proce
D. Vogt, P. S. Letelier
We present analytical potential-density pairs in three dimensions for the gravitational field of galaxies, obtained by thickening the multipolar expansion up to the quadrupole term. These may be interpreted as generalizations of the Miyamoto and Nagai potential-density pairs. With a suitable restriction on the possible values of the multipole moments, the de
Markus Janson, Wolfgang Brandner, Thomas Henning, Hans Zinnecker
An analysis of adaptive optics K-band imaging data of GQ Lup acquired in 1994 by the first generation adaptive optics system ComeOn+ at the ESO 3.6m optical telescope in La Silla is presented. The data reveal a likely candidate for the low-mass companion recently reported in the literature. An a posteriori detection in the 11 year old data would provide a us
N. Masetti, M. Orlandini, E. Palazzi, L. Amati
We observed with Chandra two peculiar galactic X-ray sources, 4U 1700+24 and 4U 1954+319, which are suspected to have a M-type giant star as optical counterpart, in order to get an high-precision astrometric position for both of them. The peculiarity of these sources lies in the fact that these are the only two cases among low-mass X-ray binaries (LMXBs), be
Non-Friedmann cosmology for the Local Universe, significance of the universal Hubble constant and short-distance indicators of dark energy
astro-phArthur D. Chernin, Pekka Teerikorpi, Yurij V. Baryshev
Basing on the increasing evidence for the cosmological relevance of the local Hubble flow, we consider a simple analytical cosmological model for the Local Universe. This is a non-Friedmann model with a non-uniform static space-time. The major dynamical factor controlling the local expansion is the antigravity produced by the omnipresent and permanent dark e
AGB star intershell abundances inferred from analyses of extremely hot H-deficient post-AGB stars
astro-phK. Werner, D. Jahn, T. Rauch, E. Reiff
The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell region. Thus, the photospheric element abundances of these stars allow to draw conclusions about details of nuclear bur
Chih Hao Hsia, Wing Huen Ip, Jin Zeng Li
The young planetary nebulae play an important role in stellar evolution when intermediate- to low-mass stars (0.8 $\sim$ 8 M$_\odot$) evolve from the proto-planetary nebulae phase to the planetary nebulae phase. Many young planetary nebulae display distinct bipolar structures as they evolve away from the proto-planetary nebulae phase. One possible cause of t
Hyesung Kang, T. W. Jones
We have developed a cosmic ray (CR) shock code in one dimensional spherical geometry with which the particle distribution, the gas flow and their nonlinear interaction can be followed numerically in a frame comoving with an expanding shock. In order to accommodate a very wide dynamic range of diffusion length scales in the CR shock problem, we have incorpora
Abigail S. Hedden, Christopher K. Walker, Christopher E. Groppi, Harold M. Butner
We have made continuum and spectral line observations of several outflow sources in the Mon OB1 dark cloud (NGC 2264) using the Heinrich Hertz Telescope (HHT) and ARO 12m millimeter-wave telescope. This study explores the kinematics and outflow energetics of the young stellar systems observed and assesses the impact star formation is having on the surroundin
The Possibly Remnant Massive Outflow in G5.89-0.39: I - Observations and Initial MHD Simulations
astro-phP. D. Klaassen, R. Plume, R. Ouyed, A. M. von Benda-Beckmann
We have obtained maps of the large scale outflow associated with the UCHII regionG5.89-0.39 in CO and 13CO (J=3-2), SiO (J=8-7,J=5-4), SO2 (13(2,12)-13(1,13)) and H13CO+(J=4-3). From these maps we have been able to determine the mass (3.3 M_sun), momentum (96 M_sun km/s), energy (3.5x10^{46} erg), mechanical luminosity (141 L_sun), and mass loss rate (~1x10^
Gabriela Canalizo, Alan Stockton, Michael S. Brotherton, Mark Lacy
Many of the conditions that are necessary for starbursts appear to be important in the triggering of QSOs. However, it is still debatable whether starbursts are ubiquitously present in galaxies harboring QSOs. In this paper we review our current knowledge from observations of the role of starbursts in different types of QSOs. Post-starburst stellar populatio
Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey
astro-phO. Ilbert, S. Arnouts, H. J. McCracken, M. Bolzonella
We present photometric redshifts for an uniquely large and deep sample of 522286 objects with i'_{AB}<25 in the Canada-France Legacy Survey ``Deep Survey'' fields, which cover a total effective area of 3.2 deg^2. We use 3241 spectroscopic redshifts with 0<z<5 from the VIMOS VLT Deep Survey as a calibration to derive these photometric redshifts. W
E. Middelberg
Editing of radio interferometer data, a process commonly known as ``flagging'', can be laborious and time-consuming. One quickly tends to flag more data than actually required, sacrificing sensitivity and image fidelity in the process. I describe a program, Pieflag, which can analyse radio interferometer data to filter out measurements which are like
Chemical abundances for Hf 2-2, a planetary nebula with the strongest known heavy element recombination lines
astro-phX. -W. Liu, M. J. Barlow, Y. Zhang, R. J. Bastin
We present high quality optical spectroscopic observations of the planetary nebula (PN) Hf 2-2. The spectrum exhibits many prominent optical recombination lines (ORLs) from heavy element ions. Analysis of the H {\sc i} and He {\sc i} recombination spectrum yields an electron temperature of $\sim 900$ K, a factor of ten lower than given by the collisionally e
Anatoly Spitkovsky
Pulsar spindown forms a reliable yet enigmatic prototype for the energy loss processes in many astrophysical objects including accretion disks and back holes. In this paper we review the physics of pulsar magnetospheres, concentrating on recent developments in force-free modeling of the magnetospheric structure. In particular, we discuss a new method for sol
Anatoly Spitkovsky
We discuss 3D simulations of relativistic collisionless shocks in electron-positron pair plasmas using the particle-in-cell (PIC) method. The shock structure is mainly controlled by the shock's magnetization ("sigma" parameter). We demonstrate how the structure of the shock varies as a function of sigma for perpendicular shocks. At low magnetizat
Andrea Martocchia, Giorgio Matt, Tomaso Belloni, Marco Feroci
Two XMM-Newton observations of the black-hole binary GRS1915+105 were triggered in 2004 (April 17 and 21), during a long "plateau" state of the source. We analyzed the data collected with EPIC-pn in Timing and Burst modes, respectively. No thermal disc emission is required by the data; the spectrum is well fitted by four components: a primary compone
Andrey V. Kravtsov, Alexey Vikhlinin, Daisuke Nagai
We present comparison of X-ray proxies for the total cluster mass, including the spectral temperature (Tx), gas mass measured within r500 (Mg), and the new proxy, Yx, which is a simple product of Tx and Mg and is related to the total thermal energy of the ICM. We use mock Chandra images constructed for a sample of clusters simulated with the eulerian N-body+
Antony Lewis, Anthony Challinor
Weak gravitational lensing has several important effects on the cosmic microwave background (CMB): it changes the CMB power spectra, induces non-Gaussianities, and generates a B-mode polarization signal that is an important source of confusion for the signal from primordial gravitational waves. The lensing signal can also be used to help constrain cosmologic
James A. Klimchuk
This article assesses the current state of understanding of coronal heating, outlines the key elements of a comprehensive strategy for solving the problem, and warns of obstacles that must be overcome along the way.
Michael Efroimsky
Both orbital and rotational dynamics employ the method of variation of parameters. We express, in a non-perturbed setting, the coordinates (Cartesian, in the orbital case, or Eulerian in the rotation case) via the time and six adjustable constants called elements (orbital elements or rotational elements). If, under disturbance, we use this expression as ansa
Abhishek Parakh
This paper proposes a new recursive technique using d-sequences to generate random numbers.
Niel de Beaudrap
This article is the complement to [quant-ph/0611284], which proves that flows (as introduced by [quant-ph/0506062]) can be found efficiently for patterns in the one-way measurement model which have non-empty input and output subsystems of the same size. This article presents a complete algorithm for finding flows, and a proof of its' correctness, without
Efficient quantum-chemical geometry optimization and the structure of large icosahedral fullerenes
cond-mat.mtrl-sciBrett I. Dunlap, Rajendra. R. Zope
Geometry optimization is efficient using generalized Gaunt coefficients, which significantly limit the amount of cross differentiation for multi-center integrals of high-angular-momentum solid-harmonic basis sets. We parameterize the fully analytic formulation of density functional theory (ADFT), called the Slater-Roothaan method, developed in our group to g
Mustafa Salti, Oktay Aydogdu
This paper has been removed by arXiv administrators because of overlap with gr-qc/9601044, gr-qc/0212018, hep-th/0310151, gr-qc/0011066, gr-qc/0404001, gr-qc/0304081, gr-qc/0501002, and gr-qc/0109017. This paper also has excessive overlap with the following papers also written by the authors or their collaborators: gr-qc/0606022, gr-qc/0512080, gr-qc/0511030
Jafferson K. L. da Silva, Lauro A. Barbosa, Paulo Roberto Silva
A general simple theory for the interspecific allometric scaling is developed in the $d+1$-dimensional space ($d$ biological lengths and a physiological time) of metabolic states of organisms. It is assumed that natural selection shaped the metabolic states in such a way that the mass and energy $d+1$-densities are size-invariant quantities (independent of b
M. J. Reboucas, J. S. Alcaniz
Geometry constrains but does not dictate the topology of the 3--dimensional space. In a locally spatially homogeneous and isotropic universe, however, the topology of its spatial section dictates its geometry. We show that, besides determining the geometry, the knowledge of the spatial topology through the circles--in--the--sky offers an effective way of set
Klaus Werner
The fact that nuclei have diffuse surfaces (rather than being simple spheres) has dramatic consequences on the interpretation of RHIC heavy-ion data. The effect is quite small (but not negligible) for central collisions, but gets increasingly important with decreasing centrality. One may actually divide the collision zone into a central part ("core")
Michel Van den Bergh
We give a proof of Yekutieli's global algebraic deformation quantization result which does not rely on the choice of local sections of the bundle of affine coordinate systems. Instead we use an argument inspired by algebraic De Rham cohomology.
Exact Equivalence of the D=4 Gauged Wess-Zumino-Witten Term and the D=5 Yang-Mills Chern-Simons Term
hep-thChristopher T. Hill
We derive the full Wess-Zumino-Witten term of a gauged chiral lagrangian in D=4 by starting from a pure Yang-Mills theory of gauged quark flavor in a flat, compactified D=5. The theory is compactified such that there exists a B_5 zero mode, and supplemented with quarks that are ``chirally delocalized'' with q_L (q_R) on the left (right) boundary (bra
The Extended Cartan Homotopy Formula and a Subspace Separation Method for Chern--Simons Theory
hep-thFernando Izaurieta, Eduardo Rodríguez, Patricio Salgado
In the context of Chern--Simons (CS) Theory, a subspace separation method for the Lagrangian is proposed. The method is based on the iterative use of the Extended Cartan Homotopy Formula, and allows one to (1) separate the action in bulk and boundary contributions, and (2) systematically split the Lagrangian in appropriate reflection of the the subspace stru
G. Torrieri, S. Jeon, J. Letessier, J. Rafelski
This the user's manual for SHARE version 2. SHARE (Statistical Hadronization with Resonances) is a collection of programs designed for the statistical analysis of particle production in relativistic heavy-ion collisions. While the structure of the program remains similar to v1.X, v2 provides several new features such as evaluation of statistical fluctuat
John G. Baker, Joan Centrella, Dae-Il Choi, Michael Koppitz
Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black ho
Yaakov S. Weinstein, Lorenza Viola
We demonstrate that generalized entanglement [Barnum {\em et al.}, Phys. Rev. A {\bf 68}, 032308 (2003)] provides a natural and reliable indicator of quantum chaotic behavior. Since generalized entanglement depends directly on a choice of preferred observables, exploring how generalized entanglement increases under dynamical evolution is possible without inv
The signature of the magnetorotational instability in the Reynolds and Maxwell stress tensors in accretion discs
astro-phMartin E. Pessah, Chi-kwan Chan, Dimitrios Psaltis
The magnetorotational instability is thought to be responsible for the generation of magnetohydrodynamic turbulence that leads to enhanced outward angular momentum transport in accretion discs. Here, we present the first formal analytical proof showing that, during the exponential growth of the instability, the mean (averaged over the disc scale-height) Reyn
Luiz Renato Fontes, Pierre Mathieu
We study K-processes, which are Markov processes in a denumerable state space, all of whose elements are stable, with the exception of a single state, starting from which the process enters finite sets of stable states with uniform distribution. We show how these processes arise, in a particular instance, as scaling limits of the REM-like trap model ``at low
Atish Dabholkar, Suresh Nampuri
The degeneracies of supersymmetric quarter BPS dyons in four dimensions and of spinning black holes in five dimensions in a CHL compactification are computed exactly using Borcherds lift. The Hodge anomaly in the construction has a physical interpretation as the contribution of a single M-theory Kaluza-Klein 6-brane in the 4d-5d lift. Using factorization, it
Vincenzo Cirigliano, Christopher Lee, Michael J. Ramsey-Musolf, Sean Tulin
We derive the contributions to the quantum transport equations for electroweak baryogenesis due to decays and inverse decays induced by tri-scalar and Yukawa interactions. In the Minimal Supersymmetric Standard Model (MSSM), these contributions give rise to couplings between Higgs and fermion supermultiplet densities, thereby communicating the effects of CP-
Alejandro Adem, Frederick R. Cohen
This article records basic topological, as well as homological properties of the space of homomorphisms Hom(L,G) where L is a finitely generated discrete group, and G is a Lie group, possibly non-compact. If L is a free abelian group of rank equal to n, then Hom(L,G) is the space of ordered n-tuples of commuting elements in G. If G=SU(2), a complete calculat
Pawel Wocjan, Jon Yard
We analyze relationships between quantum computation and a family of generalizations of the Jones polynomial. Extending recent work by Aharonov et al., we give efficient quantum circuits for implementing the unitary Jones-Wenzl representations of the braid group. We use these to provide new quantum algorithms for approximately evaluating a family of speciali
Kevin T. Chu, Martin Z. Bazant
We analyze the simplest problem of electrochemical relaxation in more than one dimension - the response of an uncharged, ideally polarizable metallic sphere (or cylinder) in a symmetric, binary electrolyte to a uniform electric field. In order to go beyond the circuit approximation for thin double layers, our analysis is based on the Poisson-Nernst-Planck (P
O. Cucciati, A. Iovino, C. Marinoni, O. Ilbert
We investigate the redshift and luminosity evolution of the galaxy colour-density relation using the data from the First Epoch VIMOS-VLT Deep Survey (VVDS). The size (6582 galaxies), depth (I_AB<=24) and redshift sampling rate of the survey enable us to reconstruct the 3D galaxy environment on relatively local scales (R=5 Mpc) up to z~1.5. Particular attenti
Edoardo Di Napoli, Paul H. Frampton
Abelian quiver gauge theories provide nonsupersymmetric candidates for the conformality approach to physics beyond the standard model. Written as ${\cal N}=0$, $U(N)^n$ gauge theories, however, they have mixed $U(1)_p U(1)_q^2$ and $U(1)_p SU(N)_q^2$ triangle anomalies. It is shown how to construct explicitly a compensatory term $Δ{\cal L}_{comp}$ which rest
Percolation of particles on recursive lattices: (III) percolation of polydisperse particles in the presence of a polymer matrix
cond-mat.softAndrea Corsi, P. D. Gujrati
We use a recently developed lattice model to study the percolation of particles of different sizes and shapes in the presence of a polymer matrix. The polymer is modeled as an infinitely long semiflexible chain. We study the effects of the stiffness of the polymer, the size disparity of the filler particles, their aspect ratio and the interactions between fi
Percolation of particles on recursive lattices: (II) the effect of size and shape disparities
cond-mat.softAndrea Corsi, P. D. Gujrati
The preparation of many composites requires the intermixing of several macromolecular fluids along with the addition of solid filler particles. These fillers are usuallly polydisperse and there is an extensive experimental evidence that their size and shape profoundly affects the properties of the resulting material. In particular, it is generally found that
Mary Beth Ruskai
We show how recent results of Lieb and Seiringer [math-ph/0412009; Phys. Rev. A 71, 062329 (2005)] can be obtained from repeated use of the monotonicity of relative entropy under partial traces, and explain how to use their approach to obtain tighter bounds in many situations.
Barrie W Jones, P Nick Sleep, David R Underwood
At present, because of observational selection effects, we know of no exoplanetary systems with any planetary masses close to that of the Earth. We have therefore used computer models to see whether such planets could be dynamically stable in the presence of the more massive planets known to be present, and in particular whether planets with roughly an Earth
K. P. Sinha, A. Meulenberg
Models to account for the observed experimental results for low-energy nuclear reactions in palladium-deuteride systems are presented along with calculated results. The crucial idea is a mechanism of improved probability for the needed penetration of the Coulomb barrier for a D-D reaction. This facilitation occurs, in general, with the formation of D^- ions
Mid-Infrared Identifications of SCUBA Galaxies in the CUDSS 14-Hour Field with the Spitzer Space Telescope
astro-phM. L. N. Ashby, S. Dye, J. -S. Huang, S. Eales
We identify 17 possible 8.0 micron-selected counterparts to the submillimeter galaxies in the CUDSS 14-hour field, derived from deep imaging carried out with the IRAC and MIPS instruments aboard the Spitzer Space Telescope. Ten of the 17 counterparts are not the same as those previously identified at shorter wavelengths. We argue that 8.0 micron selection of
Factorization of multiple integrals representing the density matrix of a finite segment of the Heisenberg spin chain
hep-thHerman E. Boos, Frank Göhmann, Andreas Klümper, Junji Suzuki
We consider the inhomogeneous generalization of the density matrix of a finite segment of length $m$ of the antiferromagnetic Heisenberg chain. It is a function of the temperature $T$ and the external magnetic field $h$, and further depends on $m$ `spectral parameters' $ξ_j$. For short segments of length 2 and 3 we decompose the known multiple integrals