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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0705.0498 | Seiji Yunoki | S. Yunoki, A. Moreo, E. Dagotto, S. Okamoto, S. S. Kancharla, and A.
Fujimori | Electron Doping of Cuprates via Interfaces with Manganites | 12 pages, 9 figures | Phys. Rev. B 76, 064532 (2007) | 10.1103/PhysRevB.76.064532 | null | cond-mat.str-el cond-mat.supr-con | null | The electron doping of undoped high-$T_c$ cuprates via the transfer of charge
from manganites (or other oxides) using heterostructure geometries is here
theoretically discussed. This possibility is mainly addressed via a detailed
analysis of photoemission and diffusion voltage experiments, which locate the
Fermi level of manganites above the bottom of the upper Hubbard band of some
cuprate parent compounds. A diagram with the relative location of Fermi levels
and gaps for several oxides is presented. The procedure discussed here is
generic, allowing for the qualitative prediction of the charge flow direction
at several oxide interfaces. The addition of electrons to antiferromagnetic Cu
oxides may lead to a superconducting state at the interface with minimal
quenched disorder. Model calculations using static and dynamical mean-field
theory, supplemented by a Poisson equation formalism to address charge
redistribution at the interface, support this view. The magnetic state of the
manganites could be antiferromagnetic or ferromagnetic. The former is better to
induce superconductivity than the latter, since the spin-polarized charge
transfer will be detrimental to singlet superconductivity. It is concluded that
in spite of the robust Hubbard gaps, the electron doping of undoped cuprates at
interfaces appears possible, and its realization may open an exciting area of
research in oxide heterostructures.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 16:42:00 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Yunoki",
"S.",
""
],
[
"Moreo",
"A.",
""
],
[
"Dagotto",
"E.",
""
],
[
"Okamoto",
"S.",
""
],
[
"Kancharla",
"S. S.",
""
],
[
"Fujimori",
"A.",
""
]
] |
0705.0499 | Lucas Labadie | C. Vigreux-Bercovici (LPMC), E. Bonhomme (LPMC), A. Pradel (LPMC),
J.-E. Broquin (IMEP), L. Labadie (LAOG/Mpia), P. Kern (LAOG) | Transmission measurement at 10.6 microns of Te2As3Se5 rib-waveguides on
As2S3 substrate | The following article appeared in Vigreux-Bercovici et al., Appl.
Phys. Lett. 90, 011110 (2007) and may be found at
http://link.aip.org/link/?apl/90/011110 | Appl. Phys. Lett. 90, 011110 (2007) | 10.1063/1.2430404 | null | physics.optics | null | The feasibility of chalcogenide rib waveguides working at lambda = 10.6
microns has been demonstrated. The waveguides comprised a several microns thick
Te2As3Se5 film deposited by thermal evaporation on a polished As2S3 glass
substrate and further etched by physical etching in Ar or CF4/O2 atmosphere.
Output images at 10.6 microns and some propagation losses roughly estimated at
10dB/cm proved that the obtained structures behaved as channel waveguides with
a good lateral confinement of the light. The work opens the doors to the
realisation of components able to work in the mid and thermal infrared up to 20
microns and even more.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 16:45:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vigreux-Bercovici",
"C.",
"",
"LPMC"
],
[
"Bonhomme",
"E.",
"",
"LPMC"
],
[
"Pradel",
"A.",
"",
"LPMC"
],
[
"Broquin",
"J. -E.",
"",
"IMEP"
],
[
"Labadie",
"L.",
"",
"LAOG/Mpia"
],
[
"Kern",
"P.",
"",
"LAOG"
]
] |
0705.0500 | Sebastian Goette | S. Goette and C. Zickert | The Extended Bloch Group and the Cheeger-Chern-Simons Class | LaTeX2e, 9 pages | Geom. Topol. 11 (2007) 1623-1635 | 10.2140/gt.2007.11.1623 | null | math.GT | null | We present a formula for the full Cheeger-Chern-Simons class of the
tautological flat complex vector bundle of rank two over BSL(2,\C^\delta). Our
formula improves the formula by Dupont and Zickert, where the class is only
computed modulo 2-torsion.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:25:15 GMT"
}
] | 2014-11-11T00:00:00 | [
[
"Goette",
"S.",
""
],
[
"Zickert",
"C.",
""
]
] |
0705.0501 | Alan Bray | Alan J Bray, Richard Smith | Survival of a diffusing particle in an expanding cage | 5 pages | null | 10.1088/1751-8113/40/36/002 | null | cond-mat.stat-mech math.PR | null | We consider a Brownian particle, with diffusion constant D, moving inside an
expanding d-dimensional sphere whose surface is an absorbing boundary for the
particle. The sphere has initial radius L_0 and expands at a constant rate c.
We calculate the joint probability density, p(r,t|r_0), that the particle
survives until time t, and is at a distance r from the centre of the sphere,
given that it started at a distance r_0 from the centre.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:13:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bray",
"Alan J",
""
],
[
"Smith",
"Richard",
""
]
] |
0705.0502 | Luis Benet | Luis Benet, Lewis T. Chadderton, Sergey Yu. Kun, Oleg K. Vorov and
Wang Qi | Slow cross-symmetry phase relaxation in complex collisions | 10 pages including 2 color ps figures. To be published in Physics of
Atomic Nuclei (Yadernaya fizika) | Phys.Atom.Nucl.71:819-823,2008 | 10.1134/S1063778808050086 | null | quant-ph nucl-th | null | We discuss the effect of slow phase relaxation and the spin off-diagonal
$S$-matrix correlations on the cross section energy oscillations and the time
evolution of the highly excited intermediate systems formed in complex
collisions. Such deformed intermediate complexes with strongly overlapping
resonances can be formed in heavy ion collisions, bimolecular chemical
reactions and atomic cluster collisions. The effects of quasiperiodic energy
dependence of the cross sections, coherent rotation of the hyperdeformed
$\simeq (3:1)$ intermediate complex, Schr\"odinger cat states and
quantum-classical transition are studied for $^{24}$Mg+$^{28}$Si heavy ion
scattering.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 16:57:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Benet",
"Luis",
""
],
[
"Chadderton",
"Lewis T.",
""
],
[
"Kun",
"Sergey Yu.",
""
],
[
"Vorov",
"Oleg K.",
""
],
[
"Qi",
"Wang",
""
]
] |
0705.0503 | Stefano M. Iacus | Alessandro De Gregorio, Stefano M. Iacus | Change point estimation for the telegraph process observed at discrete
times | null | null | null | null | math.ST math.PR q-fin.ST stat.ME stat.TH | null | The telegraph process models a random motion with finite velocity and it is
usually proposed as an alternative to diffusion models. The process describes
the position of a particle moving on the real line, alternatively with constant
velocity $+ v$ or $-v$. The changes of direction are governed by an homogeneous
Poisson process with rate $\lambda >0.$ In this paper, we consider a change
point estimation problem for the rate of the underlying Poisson process by
means of least squares method. The consistency and the rate of convergence for
the change point estimator are obtained and its asymptotic distribution is
derived. Applications to real data are also presented.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 16:59:59 GMT"
}
] | 2008-12-02T00:00:00 | [
[
"De Gregorio",
"Alessandro",
""
],
[
"Iacus",
"Stefano M.",
""
]
] |
0705.0504 | Marion Scheepers | Marion Scheepers | Rothberger's property in finite powers | 14 pages typeset | null | null | null | math.LO math.CO | null | We show that several classical Ramseyan statements, and a forcing statement,
are each equivalent to having Rothberger's property in all finite powers.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:00:08 GMT"
},
{
"version": "v2",
"created": "Tue, 23 Oct 2007 15:31:16 GMT"
}
] | 2007-10-23T00:00:00 | [
[
"Scheepers",
"Marion",
""
]
] |
0705.0505 | Georgios Pastras | Georgios Pastras | Non Supersymmetric Metastable Vacua in N=2 SYM Softly Broken to N=1 | 29 pages, 10 figures | JHEP 1310:060,2013 | 10.1007/JHEP10(2013)060 | null | hep-th | null | We find non-supersymmetric metastable vacua in four dimensional N=2 gauge
theories softly broken to N=1 by a superpotential term. First we study the
simplest case, namely the SU(2) gauge theory without flavors. We study the
spectrum and lifetime of the metastable vacuum and possible embeddings of the
model in UV complete theories. Then we consider larger gauge group theories
with flavors. We show that when we softly break them to N=1, the potential
induced on specific submanifolds of their moduli space is identical to the
potential in lower rank gauge theories. Then we show that the potential
increases when we move away from this submanifold, allowing us to construct
metastable vacua on them in the theories that can be reduced to the SU(2) case.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:00:39 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Pastras",
"Georgios",
""
]
] |
0705.0506 | Geoffrey Grimmett | Geoffrey Grimmett | Space-time percolation | null | null | null | null | math.PR | null | The contact model for the spread of disease may be viewed as a directed
percolation model on $\ZZ \times \RR$ in which the continuum axis is oriented
in the direction of increasing time. Techniques from percolation have enabled a
fairly complete analysis of the contact model at and near its critical point.
The corresponding process when the time-axis is unoriented is an undirected
percolation model to which now standard techniques may be applied. One may
construct in similar vein a random-cluster model on $\ZZ \times \RR$, with
associated continuum Ising and Potts models. These models are of independent
interest, in addition to providing a path-integral representation of the
quantum Ising model with transverse field. This representation may be used to
obtain a bound on the entanglement of a finite set of spins in the quantum
Ising model on $\ZZ$, where this entanglement is measured via the entropy of
the reduced density matrix. The mean-field version of the quantum Ising model
gives rise to a random-cluster model on $K_n \times \RR$, thereby extending the
Erdos-Renyi random graph on the complete graph $K_n$.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:01:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Grimmett",
"Geoffrey",
""
]
] |
0705.0507 | Sonmez Sahutoglu | Sonmez Sahutoglu | Strong Stein neighborhood bases | 14 pages, fixed same references, to appear in Complex Var. Elliptic
Equ | Complex Var. Elliptic Equ. 57 (2012), no.10, 1073-1085 | 10.1080/17476933.2010.534785 | null | math.CV | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let D be a smooth bounded pseudoconvex domain in C^n. We give several
characterizations for the closure of D to have a strong Stein neighborhood
basis in the sense that D has a defining function r such that {z\in C^n:r(z)<a}
is pseudoconvex for sufficiently small a>0. We also show that this condition is
invariant under proper holomorphic maps that extend smoothly to the boundary.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:11:08 GMT"
},
{
"version": "v2",
"created": "Wed, 23 Dec 2009 15:11:41 GMT"
},
{
"version": "v3",
"created": "Fri, 15 Oct 2010 15:54:29 GMT"
},
{
"version": "v4",
"created": "Tue, 1 Feb 2011 04:44:40 GMT"
}
] | 2021-03-08T00:00:00 | [
[
"Sahutoglu",
"Sonmez",
""
]
] |
0705.0508 | Yaroslaw Bazaliy | Ya. B. Bazaliy | Effective attraction induced by repulsive interaction in a spin-transfer
system | null | Appl. Phys. Lett. 91, 262510 (2007) | 10.1063/1.2822407 | NSF-KITP-07-125 | cond-mat.mtrl-sci | null | In magnetic systems with dominating easy-plane anisotropy the magnetization
can be described by an effective one dimensional equation for the in-plane
angle. Re-deriving this equation in the presence of spin-transfer torques, we
obtain a description that allows for a more intuitive understanding of
spintronic devices' operation and can serve as a tool for finding new dynamic
regimes. A surprising prediction is obtained for a planar ``spin-flip
transistor'': an unstable equilibrium point can be stabilized by a current
induced torque that further repels the system from that point. Stabilization by
repulsion happens due to the presence of dissipative environment and requires a
Gilbert damping constant that is large enough to ensure overdamped dynamics at
zero current.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:43:22 GMT"
}
] | 2009-06-24T00:00:00 | [
[
"Bazaliy",
"Ya. B.",
""
]
] |
0705.0509 | Luis Benet | L. Benet, M. Bienert and S. Yu. Kun | Thermalized non-equilibrated matter and high temperature superconducting
state in quantum many-body systems | 12 pages, 1 eps figure. To be published in Radiation Effects and
Defects in Solids | Radiation Effects & Defects in Solids Vol 162 (2007) 605-612 | 10.1080/10420150701470894 | null | cond-mat.supr-con cond-mat.stat-mech nucl-ex | null | A characteristic feature of thermalized non-equilibrated matter is that, in
spite of energy relaxation--equilibration, a phase memory of the way the
many-body system was excited remains. As an example, we analyze data on a
strong forward peaking of thermal proton yield in the Bi($\gamma$,p)
photonuclear reaction. New analysis shows that the phase relaxation in
highly-excited heavy nuclei can be 8 orders of magnitude or even much longer
than the energy relaxation. We argue that thermalized non-equilibrated matter
resembles a high temperature superconducting state in quantum many-body
systems. We briefly present results on the time-dependent correlation function
of the many-particle density fluctuations for such a superconducting state. It
should be of interest to experimentally search for manifestations of
thermalized non-equilibrated matter in many-body mesoscopic systems and
nanostructures.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:12:12 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Benet",
"L.",
""
],
[
"Bienert",
"M.",
""
],
[
"Kun",
"S. Yu.",
""
]
] |
0705.0510 | Yuji Kodama | Y. Kodama and V. U. Pierce | Geometry of the Pfaff lattices | 37 pages, 5 figures | null | null | null | nlin.SI math-ph math.MP | null | Pfaff lattice was introduced by Adler and van Moerbeke to describe the
partition functions for the random matrix models of GOE and GSE type. The
partition functions of those matrix models are given by the Pfaffians of
certain skew-symmetric matrices called the moment matrices, and they are the
$\tau$-functions of the Pfaff lattice. In this paper, we study a finite version
of the Pfaff lattice equation as a Hamiltonian system. In particular, we prove
the complete integrability in the sense of Arnold-Liouville, and using a moment
map, we describe the real isospectral varieties of the Pfaff lattice. The image
of the moment map is a convex polytope whose vertices are identified as the
fixed points of the flow generated by the Pfaff lattice.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:12:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kodama",
"Y.",
""
],
[
"Pierce",
"V. U.",
""
]
] |
0705.0511 | Laszlo Kish | Andrea Sz. Kishne, Cristine L.S. Morgan, Hung-Chih Chang, Laszlo B.
Kish | Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk
Density Analysis | Regular Talk at SPIE's 4th international symposium on Fluctuations
and Noise, Conference Noise and Fluctuations in Circuits, Devices and
Materials, Florence, Italy, May 20-24, 2007 | null | 10.1117/12.724667 | null | physics.ins-det physics.gen-ph | null | Soil bulk density affects water storage, water and nutrient movement, and
plant root activity in the soil profile. Its measurement is difficult in field
conditions. Vibration-induced conductivity fluctuation was investigated to
quantify soil bulk density with possible field applications in the future. The
AC electrical conductivity of soil was measured using a pair of blade-like
electrodes while exposing the soil to periodic vibration. The blades were
positioned longitudinally and transversally to the direction of the induced
vibration to enable the calculation of a normalized index. The normalized index
was expected to provide data independent from the vibration strength and to
reduce the effect of soil salinity and water content. The experiment was
conducted on natural and salinized fine sand at two moisture conditions and
four bulk densities. The blade-shaped electrodes improved electrode-soil
contact compared to cylindrical electrodes, and thereby, reduced measurement
noise. Simulations on a simplified resistor lattice indicate that the
transversal effect increases as soil bulk density decreases. Measurement of dry
sand showed a negative correlation between the normalized conductivity
fluctuation and soil bulk density for both longitudinal and transversal
settings. The decrease in the transversal signal was smaller than expected. The
wet natural and salinized soils performed very similarly as hypothesized, but
their normalized VICOF response was not significant to bulk density changes.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:20:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kishne",
"Andrea Sz.",
""
],
[
"Morgan",
"Cristine L. S.",
""
],
[
"Chang",
"Hung-Chih",
""
],
[
"Kish",
"Laszlo B.",
""
]
] |
0705.0512 | Ting-Hui Lee | T.-H. Lee, J. Lim, S. Kwok | Optically Thick Radio Cores of Narrow-Waist Bipolar Nebulae | 29 pages, accepted for publication in ApJ | Astrophys.J.665:341-354,2007 | 10.1086/519270 | null | astro-ph | null | We report our search for optically thick radio cores in sixteen narrow-waist
bipolar nebulae. Optically thick cores are a characteristic signature of
collimated ionized winds. Eleven northern nebulae were observed with the Very
Large Array (VLA) at 1.3 cm and 0.7 cm, and five southern nebulae were observed
with the Australia Telescope Compact Array (ATCA) at 6 cm and 3.6 cm. Two
northern objects, 19W32 and M 1-91, and three southern objects, He 2-25, He
2-84 and Mz 3, were found to exhibit a compact radio core with a rising
spectrum consistent with an ionized jet. Such jets have been seen in M 2-9 and
may be responsible for shaping bipolar structure in planetary nebulae.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:48:11 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Lee",
"T. -H.",
""
],
[
"Lim",
"J.",
""
],
[
"Kwok",
"S.",
""
]
] |
0705.0513 | Thomas Murphy Jr. | T. W. Murphy Jr., K. Nordtvedt, S. G. Turyshev | Murphy et al. Reply to the Comment by Kopeikin on "Gravitomagnetic
Influence on Gyroscopes and on the Lunar Orbit" | 1 page; accepted for publication in Physcal Review Letters; refers to
gr-qc/0702028 | Phys.Rev.Lett.98:229002,2007 | 10.1103/PhysRevLett.98.229002 | null | gr-qc | null | Lunar laser ranging analysis, as regularly performed in the solar system
barycentric frame, requires the presence of the gravitomagnetic term in the
equation of motion at the strength predicted by general relativity. The same
term is responsible for the Lense Thirring effect. Any attempt to modify the
strength of the gravitomagnetic interaction would have to do so in a way that
does not destroy the fit to lunar ranging data and other observations.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:34:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Murphy",
"T. W.",
"Jr."
],
[
"Nordtvedt",
"K.",
""
],
[
"Turyshev",
"S. G.",
""
]
] |
0705.0514 | Michele Campisi | Michele Campisi | Space-time resolved electrokinetics in cylindrical and semi-cylindrical
microchannels | 3 pages, 1 figure | null | null | null | cond-mat.soft | null | It is shown show how to employ Bessel-Fourier series in order to obtain a
complete space-time resolved description of electrokinetic phenomena in
cylindrical and semi-cylindrical microfluidic channels.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 17:51:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Campisi",
"Michele",
""
]
] |
0705.0515 | Daryl Achilles | Daryl Achilles, Ekaterina Rogacheva, and Alexei Trifonov | Fast quantum key distribution with decoy number states | 15 pages, 6 figures; Accepted to J. Mod. Opt | null | 10.1080/09500340701441293 | null | quant-ph | null | We investigate the use of photon number states to identify eavesdropping
attacks on quantum key distribution (QKD) schemes. The technique is based on
the fact that different photon numbers traverse a channel with different
transmittivity. We then describe two QKD schemes that utilize this method, one
of which overcomes the upper limit on the key generation rate imposed by the
dead time of detectors when using a heralded source of photons.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:10:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Achilles",
"Daryl",
""
],
[
"Rogacheva",
"Ekaterina",
""
],
[
"Trifonov",
"Alexei",
""
]
] |
0705.0516 | Valerie Hower | Valerie Hower | Hodge Spaces for Real Toric Varieties | 22 pages, 2 figures | null | null | null | math.AG math.AT | null | We define the Z/2Z Hodge spaces H_{pq}(\Sigma) of a fan \Sigma.
If \Sigma is the normal fan of a reflexive polytope \Delta then we use
polyhedral duality to compute the Z/2Z Hodge Spaces of \Sigma. In particular,
if the cones of dimension at most e in the face fan \Sigma^* of \Delta are
smooth then we compute H_{pq}(\Sigma) for p<e-1. If \Sigma^* is a smooth fan
then we completely determine the spaces H_{pq}(\Sigma) and we show the toric
variety X associated to \Sigma is maximal, meaning that the sum of the Z/2Z
Betti numbers of X(R) is equal to the sum of the Z/2Z Betti numbers of X(C).
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:17:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hower",
"Valerie",
""
]
] |
0705.0517 | Lambert Alff | Y. Krockenberger (1,2), I. Fritsch (1), G. Christiani (1), H.-U.
Habermeier (1), Li Yu (1), C. Bernhard (1), B. Keimer (1), and L. Alff (2)
((1) Max-Planck-Institute for Solid State Research, Stuttgart, (2) Institute
of Materials Science, Darmstadt University of Technology) | Superconductivity in epitaxial thin films of NaxCoO2 y D2O | 3 pages, 5 figures | Appl. Phys. Lett. 88, 162501 (2006) | 10.1063/1.2196061 | null | cond-mat.supr-con cond-mat.mtrl-sci | null | The observation of superconductivity in the layered transition metal oxide
NaxCoO2 y H2O (K. Takada et al., Nature 422, 53 (2003)) has caused a tremendous
upsurge of scientific interest due to its similarities and its differences to
the copper based high-temperature superconductors. Two years after the
discovery, we report the fabrication of single-phase superconducting epitaxial
thin films of Na0.3CoO2 x 1.3 D2O grown by pulsed laser deposition technique.
This opens additional roads for experimental research exploring the
superconducting state and the phase diagram of this unconventional material.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:39:29 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Krockenberger",
"Y.",
""
],
[
"Fritsch",
"I.",
""
],
[
"Christiani",
"G.",
""
],
[
"Habermeier",
"H. -U.",
""
],
[
"Yu",
"Li",
""
],
[
"Bernhard",
"C.",
""
],
[
"Keimer",
"B.",
""
],
[
"Alff",
"L.",
""
]
] |
0705.0518 | Stefko Miklavic | Stefko Miklavic | Leonard triples and hypercubes | 26 pages | null | null | null | math.CO math.RA | null | Let $V$ denote a vector space over C with finite positive dimension. By a
{\em Leonard triple} on $V$ we mean an ordered triple of linear operators on
$V$ such that for each of these operators there exists a basis of $V$ with
respect to which the matrix representing that operator is diagonal and the
matrices representing the other two operators are irreducible tridiagonal. Let
$D$ denote a positive integer and let $Q_D$ denote the graph of the
$D$-dimensional hypercube. Let $X$ denote the vertex set of $Q_D$ and let $A$
denote the adjacency matrix of $Q_D$. Fix $x \in X$ and let $A^*$ denote the
corresponding dual adjacency matrix. Let $T$ denote the subalgebra of
$Mat_X(C)$ generated by $A, A^*$. We refer to $T$ as the {\em Terwilliger
algebra of} $Q_D$ {\em with respect to} $x$. The matrices $A$ and $A^*$ are
related by the fact that $2 \im A = A^* A^e - A^e A^*$ and $2 \im A^* = A^e A -
A A^e$, where $2 \im A^e = A A^* - A^* A$ and $\im^2=-1$. We show that the
triple $A$, $A^*$, $A^e$ acts on each irreducible $T$-module as a Leonard
triple. We give a detailed description of these Leonard triples.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:25:54 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Apr 2008 09:26:14 GMT"
}
] | 2008-04-10T00:00:00 | [
[
"Miklavic",
"Stefko",
""
]
] |
0705.0519 | Nicolas Bouleau | Nicolas Bouleau (CIRED) | Bringing errors into focus | 27 pages | null | null | null | math.PR math.DG math.NA | null | This lecture presents recent advances in the theory of errors propagation. We
first explain in which cases the propagation of errors may be performed with a
first order differential calculus or needs a second order differential
calculus. Then we point out the link between error propagation and the concept
of second order vector in differential geometry, emphasizing the existence of a
slight ambiguity concerning the bias operator. The third part in devoted to the
powerful framework of Dirichlet forms whose main feature is to apply easily to
infinite dimensional models including the Wiener space (giving an
interpretation of Malliavin calculus in terms of errors), the Poisson space and
the Monte Carlo space. In the fourth part we show how an error in the usual
mathematical sense, i.e. an approximate quantity, may yield a Dirichlet form
and we introduce the four bias operators. Eventually we connect the Dirichlet
form with statistics by identifying the square of field operator with the
inverse of the Fisher information matrix.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:30:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bouleau",
"Nicolas",
"",
"CIRED"
]
] |
0705.0520 | Pedro Daniel Gonzalez Perez | Pedro Daniel Gonzalez Perez (UCM) | Bijectiveness of the Nash Map for Quasi-Ordinary Hypersurface
Singularities | comments and references added | International Mathematics Research Notices (2007) 13 pages | 10.1093/imrn/rnm076 | null | math.AG | null | In this paper we give a positive answer to a question of Nash concerning the
arc space of a singularity, for the class of quasi-ordinary hypersurface
singularities, extending to this case previous results and techniques of
Shihoko Ishii.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:31:17 GMT"
},
{
"version": "v2",
"created": "Thu, 17 May 2007 18:35:00 GMT"
}
] | 2008-01-28T00:00:00 | [
[
"Perez",
"Pedro Daniel Gonzalez",
"",
"UCM"
]
] |
0705.0521 | Paolo Gondolo | Douglas Spolyar, Katherine Freese, Paolo Gondolo | Dark matter and the first stars: a new phase of stellar evolution | 5 pages, 2 figures; replaced with accepted version | Phys.Rev.Lett.100:051101,2008 | 10.1103/PhysRevLett.100.051101 | null | astro-ph hep-ph hep-th | null | A mechanism is identified whereby dark matter (DM) in protostellar halos
dramatically alters the current theoretical framework for the formation of the
first stars. Heat from neutralino DM annihilation is shown to overwhelm any
cooling mechanism, consequently impeding the star formation process and
possibly leading to a new stellar phase. A "dark star'' may result: a giant
($\gtrsim 1$ AU) hydrogen-helium star powered by DM annihilation instead of
nuclear fusion. Observational consequences are discussed.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 18:49:36 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Dec 2007 21:13:44 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Spolyar",
"Douglas",
""
],
[
"Freese",
"Katherine",
""
],
[
"Gondolo",
"Paolo",
""
]
] |
0705.0522 | Martina Hentschel | Martina Hentschel and Francisco Guinea | Orthogonality catastrophe and Kondo effect in graphene | 7 pages, 7 figures | Phys. Rev. B 76, 115407 (2007) | 10.1103/PhysRevB.76.115407 | null | cond-mat.mes-hall | null | Anderson's orthogonality catastrophe in graphene, at energies close to the
Dirac point, is analyzed. It is shown that, in clean systems, the orthogonality
catastrophe is suppressed, due to the vanishing density of states at the Dirac
point. In the presence of preexisting localized states at the Dirac energy, the
orthogonality catastrophe shows similar features to those found in normal
metals with a finite density of states at the Fermi level. The implications for
the Kondo effect induced by magnetic impurities, and for the Fermi edge
singularities in tunneling processes are also discussed.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:11:02 GMT"
}
] | 2008-02-06T00:00:00 | [
[
"Hentschel",
"Martina",
""
],
[
"Guinea",
"Francisco",
""
]
] |
0705.0523 | Matthew B. Stone | M. B. Stone, W. Tian, M. D. Lumsden, G. E. Granroth, D. Mandrus, J.-H.
Chung, N. Harrison and S. E. Nagler | Quantum spin correlations in an organometallic alternating sign chain | 5 pages, 4 figures included in text. Submitted to APS Journals | null | 10.1103/PhysRevLett.99.087204 | null | cond-mat.str-el | null | High resolution inelastic neutron scattering is used to study excitations in
the organometallic magnet DMACuCl$_3$. The correct magnetic Hamiltonian
describing this material has been debated for many years. Combined with high
field bulk magnetization and susceptibility studies, the new results imply that
DMACuCl$_3$ is a realization of the $S=1/2$ alternating
antiferromagnetic-ferromagnetic (AFM-FM) chain. Coupled-cluster calculations
are used to derive exchange parameters, showing that the AFM and FM
interactions have nearly the same strength. Analysis of the scattering
intensities shows clear evidence for inter-dimer spin correlations, in contrast
to existing results for conventional alternating chains. The results are
discussed in the context of recent ideas concerning quantum entanglement.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:49:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stone",
"M. B.",
""
],
[
"Tian",
"W.",
""
],
[
"Lumsden",
"M. D.",
""
],
[
"Granroth",
"G. E.",
""
],
[
"Mandrus",
"D.",
""
],
[
"Chung",
"J. -H.",
""
],
[
"Harrison",
"N.",
""
],
[
"Nagler",
"S. E.",
""
]
] |
0705.0524 | Scott Nollet | Scott Nollet, Laurence R. Taylor, and Frederico Xavier | Birationality of \'etale morphisms via surgery | 17 pages. Replaced to add further references and make language more
consistent with the literature | J. Reine Angew. Math. 627 (2009), 83--95 | 10.1515/CRELLE.2009.012 | null | math.AG math.GT | null | We use a counting argument and surgery theory to show that if $D$ is a
sufficiently general algebraic hypersurface in $\Bbb C^n$, then any local
diffeomorphism $F:X \to \Bbb C^n$ of simply connected manifolds which is a
$d$-sheeted cover away from $D$ has degree $d=1$ or $d=\infty$ (however all
degrees $d > 1$ are possible if $F$ fails to be a local diffeomorphism at even
a single point). In particular, any \'etale morphism $F:X \to \Bbb C^n$ of
algebraic varieties which covers away from such a hypersurface $D$ must be
birational.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:49:20 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Oct 2007 06:41:18 GMT"
}
] | 2012-11-21T00:00:00 | [
[
"Nollet",
"Scott",
""
],
[
"Taylor",
"Laurence R.",
""
],
[
"Xavier",
"Frederico",
""
]
] |
0705.0525 | Siming Liu | Siming Liu, Christopher L. Fryer, and Hui Li | Black Hole Accretion in Low States: Electron Heating | 25 pages, 2 figures, submitted to ApJ | null | null | null | astro-ph | null | Plasmas in an accretion flow are heated by MHD turbulence generated through
the magneto-rotational instability. The viscous stress driving the accretion is
intimately connected to the microscopic processes of turbulence dissipation. We
show that, in a few well-observed black hole accretion systems, there is
compelling observational evidence of efficient electron heating by turbulence
or collective plasma effects in low accretion states, when Coulomb collisions
are not efficient enough to establish a thermal equilibrium between electrons
and ions at small radii. However, charged particles reach a thermal equilibrium
with their kind much faster than with others through Coulomb collisions, a
two-temperature accretion flow is expected. We consider a Keplerian accretion
flow with a constant mass accretion rate in the pseudo-Newtonian gravitational
potential and take into account the bremsstrahlung, synchrotron, and inverse
Comptonization cooling processes. The critical mass accretion rate, below which
the two-temperature solution may exist, is determined by the cooling processes
and the collisional energy exchanges between electrons and ions and has very
weak dependence on the collision-less heating of electrons by turbulence, which
becomes more important at lower accretion rates. Collision-less heating of
electrons by MHD turbulence can no longer be ignored in quantitative
investigations of these systems.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:52:03 GMT"
},
{
"version": "v2",
"created": "Tue, 3 Jul 2007 21:10:19 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Liu",
"Siming",
""
],
[
"Fryer",
"Christopher L.",
""
],
[
"Li",
"Hui",
""
]
] |
0705.0526 | Ali Hanks | Ali Hanks (for the PHENIX Collaboration) | Measuring Bremsstrahlung Photons in 200 GeV p+p Collisions | 5 pages, 4 figures, poster presented at the 19th International
Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2006) | Int.J.Mod.Phys.E16:2182-2186,2007 | 10.1142/S0218301307007659 | null | nucl-ex | null | Direct photon production is an important observable in heavy ion collisions
as photons are penetrating and therefore largely insensetive to final state
effects that lead to jet quenching. Measurements of the fragmentation component
to prompt photon yields in p+p and Au+Au collisions will provide both an
important test of pQCD predictions and of predictions for modifications of this
component in heavy ion collisions. By selecting photons associated with jets on
the near side using hadron-photon correlations, fragmentation photons can be
measured directly.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 19:54:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hanks",
"Ali",
"",
"for the PHENIX Collaboration"
]
] |
0705.0527 | Miriam del Valle | Miriam del Valle, Rafael Gutierrez, Carlos Tejedor and Gianaurelio
Cuniberti | Tuning the conductance of a molecular switch | null | NatureNanotech.2:176,2007 | 10.1038/nnano.2007.38 | null | cond-mat.mes-hall | null | The ability to control the conductance of single molecules will have a major
impact in nanoscale electronics. Azobenzene, a molecule that changes
conformation as a result of a trans/cis transition when exposed to radiation,
could form the basis of a light-driven molecular switch. It is therefore
crucial to clarify the electrical transport characteristics of this molecule.
Here, we investigate theoretically charge transport in a system in which a
single azobenzene molecule is attached to two carbon nanotubes. In clear
contrast to gold electrodes, the nanotubes can act as true nanoscale electrodes
and we show that the low-energy conduction properties of the junction may be
dramatically modified by changing the topology of the contacts between the
nanotubes and the molecules, and/or the chirality of the nanotubes (that is,
zigzag or armchair). We propose experiments to demonstrate controlled
electrical switching with nanotube electrodes.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 21:50:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"del Valle",
"Miriam",
""
],
[
"Gutierrez",
"Rafael",
""
],
[
"Tejedor",
"Carlos",
""
],
[
"Cuniberti",
"Gianaurelio",
""
]
] |
0705.0528 | Dean Alvis | Dean Alvis | Subrings of the asymptotic Hecke algebra of type $H_4$ | null | null | null | null | math.RT math.RA | null | The structure of subring $J^{\Gamma \cap \Gamma^{-1}}$ of the asymptotic
Hecke algebra is described for $\Gamma$ a left cell of the Coxeter group of
type $H_4$. A small set of generators is produced. The subalgebras spanned by a
subset of the basis ${t_x}_{x\in \Gamma\cap\Gamma^{-1}}$ are determined.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:41:38 GMT"
},
{
"version": "v2",
"created": "Tue, 22 May 2007 15:42:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Alvis",
"Dean",
""
]
] |
0705.0529 | Sen Zhou | Meng Gao, Sen Zhou, and Ziqiang Wang | Itinerant and localized magnetism on the triangular lattice: sodium rich
phases of Na$_x$CoO$_2$ | revtex4 file, 5 pages, 3 figures, published version | Phys. Rev. B 76, 180402(R) (2007) | 10.1103/PhysRevB.76.180402 | null | cond-mat.str-el | null | We study the interplay between correlation, itinerant ferromagnetism and
local moment formation on the electron doped triangular lattice of sodium
cobaltates Na$_x$CoO$_2$. We find that strong correlation renormalizes the
Stoner criterion and stabilizes the paramagnetic state for $x<x_c\simeq0.67$.
For $x>x_c$, ferromagnetic (FM) order emerges. The enhanced Na dopant potential
fluctuations play a crucial role in the sodium rich phases and lead to an
inhomogeneous FM state, exhibiting nonmagnetic Co$^{3+}$ patches,
antiferromagnetic (AF) correlated regions, and FM clusters with AF domains.
Hole doping the band insulator at x=1 leads to the formation of local moments
near the Na vacancies and AF correlated magnetic clusters. We explain recent
observations by neutron, $\mu$SR, and NMR experiments on the evolution of the
magnetic properties in the sodium rich phases.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 00:23:41 GMT"
},
{
"version": "v2",
"created": "Tue, 13 Nov 2007 15:11:55 GMT"
}
] | 2007-11-13T00:00:00 | [
[
"Gao",
"Meng",
""
],
[
"Zhou",
"Sen",
""
],
[
"Wang",
"Ziqiang",
""
]
] |
0705.0530 | A. V. Maccio' | Simone M. Weinmann (1), Andrea V. Maccio'(2), Ilian T. Iliev (3),
Garrelt Mellema (4), Ben Moore (1) ((1) University of Zurich, (2) MPIA, (3)
CITA, (4) Stockholm Observatory) | Dependence of the Local Reionization History on Halo Mass and
Environment: Did Virgo Reionize the Local Group? | 11 pages, 7 figures. Accepted for publication in MNRAS. Methodology
section rewritten for clarity, results and conclusions unchanged. A preprint
with high-resolution figures is available at
http://www-theorie.physik.unizh.ch/~andrea/Reion/ | null | 10.1111/j.1365-2966.2007.12279.x | null | astro-ph | null | The reionization of the Universe has profound effects on the way galaxies
form and on their observed properties at later times. Of particular importance
is the relative timing of the reionization history of a region and its halo
assembly history, which can affect the nature of the first stars formed in that
region, the properties and radial distribution of its stellar halo, globular
cluster population and its satellite galaxies. We distinguish two basic cases
for the reionization of a halo - internal reionization, whereby the stars
forming in situ reionize their host galaxy, and external reionization, whereby
the progenitor of a galaxy is reionized by external radiation before its own
stars are able to form in sufficient numbers. We use a set of large-scale
radiative transfer and structure formation simulations, based on cosmologies
derived from both WMAP 1-year and WMAP 3-year data, to evaluate the mean
reionization redshifts and the probability of internal/external reionization
for Local Group-like systems, galaxies in the field and central cD galaxies in
clusters. We find that these probabilities are strongly dependent on the
underlying cosmology and the efficiency of photon production, but also on the
halo mass. There is a rapid transition between predominantly external and
predominantly internal reionization at a mass scale of 1.0e12 Msun
(corresponding roughly to L*galaxies), with haloes less massive than this being
reionized preferentially from distant sources. We provide a fit for the
reionization redshift as a function of halo mass, which could be helpful to
parameterize reionization in semi-analytical models of galaxy formation on
cosmological scales. We find no statistical correlation between the
reionization history of field galaxies and their environment.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:00:39 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 13:42:22 GMT"
},
{
"version": "v3",
"created": "Fri, 27 Jul 2007 16:02:37 GMT"
},
{
"version": "v4",
"created": "Thu, 23 Aug 2007 15:01:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Weinmann",
"Simone M.",
""
],
[
"Maccio'",
"Andrea V.",
""
],
[
"Iliev",
"Ilian T.",
""
],
[
"Mellema",
"Garrelt",
""
],
[
"Moore",
"Ben",
""
]
] |
0705.0531 | Eric Hallman | Eric J. Hallman (1), Jack O. Burns (1), Patrick M. Motl (2), Michael
L. Norman (3) ((1) Center for Astrophysics and Space Astronomy, University of
Colorado, (2) Department of Physics and Astronomy, Louisiana State
University, (3) Center for Astrophysics and Space Sciences, University of
California-San Diego) | The Beta-Model Problem: The Incompatibility of X-ray and
Sunyaev-Zeldovich Effect Model Fitting for Galaxy Clusters | Accepted to The Astrophysical Journal, 10 pages, 9 figures,
emulateapj style | Astrophys.J.665:911-920,2007 | 10.1086/519447 | null | astro-ph | null | We have analyzed a large sample of numerically simulated clusters to
demonstrate the adverse effects resulting from use of X-ray fitted beta-model
parameters with Sunyaev-Zeldovich effect (SZE) data. There is a fundamental
incompatibility between model fits to X-ray surface brightness profiles and
those done with SZE profiles. Since observational SZE radial profiles are in
short supply, the X-ray parameters are often used in SZE analysis. We show that
this leads to biased estimates of the integrated Compton y-parameter inside
r_{500} calculated from clusters. We suggest a simple correction of the method,
using a non-isothermal beta-model modified by a universal temperature profile,
which brings these calculated quantities into closer agreement with the true
values.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:00:50 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Hallman",
"Eric J.",
""
],
[
"Burns",
"Jack O.",
""
],
[
"Motl",
"Patrick M.",
""
],
[
"Norman",
"Michael L.",
""
]
] |
0705.0532 | Ivar Martin | Ivar Martin, Ya. M. Blanter | Transport in disordered graphene nanoribbons | 5 pages, 3 figures. version as published in PRB | Phys. Rev. B 79, 235132 (2009) | 10.1103/PhysRevB.79.235132 | null | cond-mat.mes-hall cond-mat.dis-nn | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study electronic transport in graphene nanoribbons with rough edges. We
first consider a model of weak disorder that corresponds to an armchair ribbon
whose width randomly changes by a single unit cell size. We find that in this
case, the low-temperature conductivity is governed by an effective
one-dimensional hopping between segments of distinct band structure. We then
provide numerical evidence and qualitative arguments that similar behavior also
occurs in the limit of strong uncorrelated boundary disorder.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:52:24 GMT"
},
{
"version": "v2",
"created": "Mon, 28 May 2007 10:47:42 GMT"
},
{
"version": "v3",
"created": "Tue, 7 Jul 2009 21:14:10 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Martin",
"Ivar",
""
],
[
"Blanter",
"Ya. M.",
""
]
] |
0705.0533 | Lesgourgues | J. Lesgourgues, M. Viel, M.G. Haehnelt, R. Massey | A combined analysis of 3D Weak Lensing, Lyman-alpha forest and WMAP year
three data | 7 pages, 2 figures; version accepted in JCAP, weak lensing module for
CosmoMC available at http://www.astro.caltech.edu/~rjm/cosmos/cosmomc/ | JCAP0711:008,2007 | 10.1088/1475-7516/2007/11/008 | LAPTH-1182/07 | astro-ph | null | We present constraints on the amplitude and shape of the matter power
spectrum and the density of dark matter within the framework of a standard
LambdaCDM model. We use a Markov Chain Monte Carlo approach to combine
independent measurements of the three dimensional weak gravitational lensing
shear field by the COSMOS survey, of low and high resolution Ly-alpha forest
flux power spectrum by SDSS and LUQAS, and of Cosmic Microwave Background
temperature and polarization anisotropies by WMAP. We note good agreement
between the amplitude of the matter power spectrum on intermediate and small
scales as inferred from Ly-alpha forest and lensing data. The Ly-alpha forest
data helps to break the sigma_8-Omega_m degeneracy characteristic of weak
lensing results, yielding sigma_8 = 0.876 +- 0.048 for COSMOS plus Ly-alpha
SDSS data. This is somewhat larger than the value preferred by the WMAP year
three CMB data. Combining all three data sets significantly tightens the
constraints on sigma_8, the spectral index of primordial density fluctuation
n_s, a possible running of the spectral index n_run and the matter density
Omega_m. Assuming no running, the joint constraints for COSMOS, SDSS and WMAP
are sigma_8 = 0.800 +- 0.023, n_s = 0.971 +- 0.011, Omega_m = 0.247 +- 0.016
(1-sigma error bars).
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 19:06:03 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 08:43:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lesgourgues",
"J.",
""
],
[
"Viel",
"M.",
""
],
[
"Haehnelt",
"M. G.",
""
],
[
"Massey",
"R.",
""
]
] |
0705.0534 | Matthew Schwartz | Emanuel Katz and Matthew D Schwartz | An Eta Primer: Solving the U(1) Problem with AdS/QCD | 15 pages, 6 figures; typos fixed, references added in v2 | JHEP0708:077,2007 | 10.1088/1126-6708/2007/08/077 | null | hep-ph | null | Inspired by the AdS/CFT correspondence, we study the pseudoscalar mesons of
QCD through a dual embedding in a strongly curved extra dimensional spacetime.
This model incorporates the consequences of symmetry and has very few free
parameters, due to constraints from five-dimensions and the operator product
expansion of QCD. Using as inputs the pion, kaon, and rho masses and fpi, we
compute the eta and eta prime masses to be 520 and 867 MeV, respectively. Their
decay rates into photons are also computed and found to be in good agreement
with data.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 19:40:25 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Oct 2007 21:41:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Katz",
"Emanuel",
""
],
[
"Schwartz",
"Matthew D",
""
]
] |
0705.0535 | David Kastor | David Kastor, Sourya Ray and Jennie Traschen | Do Killing-Yano tensors form a Lie Algebra? | 17 pages | Class.Quant.Grav.24:3759-3768,2007 | 10.1088/0264-9381/24/14/014 | null | hep-th | null | Killing-Yano tensors are natural generalizations of Killing vectors. We
investigate whether Killing-Yano tensors form a graded Lie algebra with respect
to the Schouten-Nijenhuis bracket. We find that this proposition does not hold
in general, but that it does hold for constant curvature spacetimes. We also
show that Minkowski and (anti)-deSitter spacetimes have the maximal number of
Killing-Yano tensors of each rank and that the algebras of these tensors under
the SN bracket are relatively simple extensions of the Poincare and (A)dS
symmetry algebras.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:09:18 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kastor",
"David",
""
],
[
"Ray",
"Sourya",
""
],
[
"Traschen",
"Jennie",
""
]
] |
0705.0536 | Mark R. Krumholz | Mark R. Krumholz (1), Richard I. Klein (2 and 3), and Christopher F.
McKee (3) ((1) Princeton University, (2) Lawrence Livermore National
Laboratory, (3) UC Berkeley) | Molecular Line Emission from Massive Protostellar Disks: Predictions for
ALMA and the EVLA | 15 pages, 9 figures, emulateapj format, accepted for publication in
ApJ. Resolution of figures severely degraded to fit within size limits.
Download the full paper from
http://www.astro.princeton.edu/~krumholz/recent.html | Astrophys.J.665:478-491,2007 | 10.1086/519305 | null | astro-ph | null | We compute the molecular line emission of massive protostellar disks by
solving the equation of radiative transfer through the cores and disks produced
by the recent radiation-hydrodynamic simulations of Krumholz, Klein, & McKee.
We find that in several representative lines the disks show brightness
temperatures of hundreds of Kelvin over velocity channels ~10 km s^-1 wide,
extending over regions hundreds of AU in size. We process the computed
intensities to model the performance of next-generation radio and submillimeter
telescopes. Our calculations show that observations using facilities such as
the EVLA and ALMA should be able to detect massive protostellar disks and
measure their rotation curves, at least in the nearest massive star-forming
regions. They should also detect significant sub-structure and non-axisymmetry
in the disks, and in some cases may be able to detect star-disk velocity
offsets of a few km s^-1, both of which are the result of strong gravitational
instability in massive disks. We use our simulations to explore the strengths
and weaknesses of different observational techniques, and we also discuss how
observations of massive protostellar disks may be used to distinguish between
alternative models of massive star formation.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:27:08 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Krumholz",
"Mark R.",
"",
"2 and 3"
],
[
"Klein",
"Richard I.",
"",
"2 and 3"
],
[
"McKee",
"Christopher F.",
""
]
] |
0705.0537 | Dirk Englund | Dirk Englund, Hatice Altug, Ilya Fushman, Jelena Vuckovic | Terahertz Room-Temperature Photonic Crystal Nanocavity Laser | 6 pages, 3 figures | null | 10.1063/1.2770767 | null | quant-ph | null | We describe an efficient surface-passivated photonic crystal nanocavity
laser, demonstrating room-temperature operation with 3-ps total pulse duration
(detector response limited) and low-temperature operation with
ultra-low-threshold near 9uW.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 23:46:41 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Jun 2007 10:12:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Englund",
"Dirk",
""
],
[
"Altug",
"Hatice",
""
],
[
"Fushman",
"Ilya",
""
],
[
"Vuckovic",
"Jelena",
""
]
] |
0705.0538 | Sarah C. Gallagher | S. C. Gallagher (UCLA), D. C. Hines (SSI), M. Blaylock (Steward), R.
S. Priddey (Hertfordshire), W. N. Brandt (Penn State), E. E. Egami (Steward) | Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption
Line Quasars | 21 pages, LaTeX, uses emulateapj. 12 figures (2 color). Accepted for
publication in ApJ | Astrophys.J.665:157-173,2007 | 10.1086/519438 | null | astro-ph | null | We have compiled the largest sample of multiwavelength spectral energy
distributions (SEDs) of Broad Absorption Line (BAL) quasars to date, from the
radio to the X-ray. We present new Spitzer MIPS (24, 70, and 160 micron)
observations of 38 BAL quasars in addition to data from the literature and
public archives. In general, the mid-infrared properties of BAL quasars are
consistent with those of non-BAL quasars of comparable luminosity. In
particular, the optical-to-mid-infrared luminosity ratios of the two
populations are indistinguishable. We also measure or place upper limits on the
contribution of star formation to the far-infrared power. Of 22 (57%) upper
limits, seven quasars have sufficiently sensitive constraints to conclude that
star formation likely contributes little (<20%) to their far-infrared power.
The 17 BAL quasars (45%) with detected excess far-infrared emission likely host
hyperluminous starbursts with L_fir,SF=10^{13-14} L_sun. Mid-infrared through
X-ray composite BAL quasar SEDs are presented, incorporating all of the
available photometry. Overall, we find no compelling evidence for inherent
differences between the SEDs of BAL vs. non-BAL quasars of comparable
luminosity. Therefore a ``cocoon'' picture of a typical BAL quasar outflow
whereby the wind covers a large fraction of the sky is not supported by the
mid-infrared SED comparison with normal quasars, and the disk-wind paradigm
with a typical radio-quiet quasar hosting a BAL region remains viable.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:31:15 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Gallagher",
"S. C.",
"",
"UCLA"
],
[
"Hines",
"D. C.",
"",
"SSI"
],
[
"Blaylock",
"M.",
"",
"Steward"
],
[
"Priddey",
"R. S.",
"",
"Hertfordshire"
],
[
"Brandt",
"W. N.",
"",
"Penn State"
],
[
"Egami",
"E. E.",
"",
"Steward"
]
] |
0705.0539 | Ely Kerman | Ely Kerman | Displacement energy of coisotropic submanifolds and Hofer's geometry | 23 pages | null | null | null | math.SG math.DG | null | We prove that the displacement energy of a stable coisotropic submanifold is
bounded away from zero if the ambient symplectic manifold is closed, rational
and satisfies a mild topological condition.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 20:59:04 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 15:46:27 GMT"
}
] | 2007-10-04T00:00:00 | [
[
"Kerman",
"Ely",
""
]
] |
0705.0540 | Jon M. Miller | J. M. Miller (University of Michigan) | Relativistic X-ray Lines from the Inner Accretion Disks Around Black
Holes | 40 pages, includes color figures, to appear in ARAA, vol 45, in press | Ann.Rev.Astron.Astrophys.45:441-479,2007 | 10.1146/annurev.astro.45.051806.110555 | null | astro-ph | null | Relativistic X-ray emission lines from the inner accretion disk around black
holes are reviewed. Recent observations with the Chandra X-ray Observatory,
X-ray Multi-Mirror Mission-Newton, and Suzaku are revealing these lines to be
good probes of strong gravitational effects. A number of important
observational and theoretical developments are highlighted, including evidence
of black hole spin and effects such as gravitational light bending, the
detection of relativistic lines in stellar-mass black holes, and evidence of
orbital-timescale line flux variability. In addition, the robustness of the
relativistic disk lines against absorption, scattering, and continuum effects
is discussed. Finally, prospects for improved measures of black hole spin and
understanding the spin history of supermassive black holes in the context of
black hole-galaxy co-evolution are presented. The best data and most rigorous
results strongly suggest that relativistic X-ray disk lines can drive future
explorations of General Relativity and disk physics.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 21:00:46 GMT"
},
{
"version": "v2",
"created": "Tue, 29 May 2007 18:35:32 GMT"
},
{
"version": "v3",
"created": "Wed, 6 Jun 2007 15:33:00 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Miller",
"J. M.",
"",
"University of Michigan"
]
] |
0705.0541 | Arias Maria Laura | L. S. Cidale, M. L. Arias, A. F. Torres, J. Zorec, Y. Fr\'emat, A.
Cruzado | Fundamental Parameters of He-Weak and He-Strong Stars | Accepted for publication in A&A | null | 10.1051/0004-6361:20066454 | null | astro-ph | null | We carried out low resolution spectroscopic observations in the wavelength
range 3400-4700 A of 20 He-weak and 8 He-strong stars to determine their
fundamental parameters by means of the Divan-Chalonge-Barbier (BCD)
spectrophotometric system. For a few He-weak stars we also estimate the
effective temperatures and the angular diameters by integrating absolute fluxes
observed over a wide spectral range. Non-LTE model calculations are carried out
to study the influence of the He/H abundance ratio on the emergent radiation of
He-strong stars and on their Teff determination. We find that the effective
temperatures, surface gravities and bolometric absolute magnitudes of He-weak
stars estimated with the BCD system and the integrated flux method are in good
agreement between each other, and they also agree with previous determinations
based on several different methods. The mean discrepancy between the visual
absolute magnitudes derived using the Hipparcos parallaxes and the BCD values
is on average 0.3 mag for He-weak stars, while it is 0.5 mag for He-strong
stars. For He-strong stars, we note that the BCD calibration, based on stars in
the solar environment, leads to overestimated values of Teff. By means of model
atmosphere calculations with enhanced He/H abundance ratios we show that larger
He/H ratios produce smaller BD which naturally explains the Teff
overestimation. We take advantage of these calculations to introduce a method
to estimate the He/H abundance ratio in He-strong stars. The BD of HD 37479
suggests that the Teff of this star remains fairly constant as the star
spectrum undergoes changes in the intensity of H and He absorption lines. Data
for the He-strong star HD 66765 are reported for the first time.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 21:54:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cidale",
"L. S.",
""
],
[
"Arias",
"M. L.",
""
],
[
"Torres",
"A. F.",
""
],
[
"Zorec",
"J.",
""
],
[
"Frémat",
"Y.",
""
],
[
"Cruzado",
"A.",
""
]
] |
0705.0542 | Matthew Buckley | M.R. Buckley, H. Murayama | Quark mass uncertainties revive KSVZ axion dark matter | 9 pages, 5 figures | JCAP 0707:012,2007 | 10.1088/1475-7516/2007/07/012 | null | hep-ph | null | The Kaplan-Manohar ambiguity in light quark masses allows for a larger
uncertainty in the ratio of up to down quark masses than naive estimates from
the chiral Lagrangian would indicate. We show that it allows for a relaxation
of experimental bounds on the QCD axion, specifically KSVZ axions in the $2-3
\mu$eV mass range composing 100% of the galactic dark matter halo can evade the
experimental limits placed by the ADMX collaboration.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 21:59:05 GMT"
},
{
"version": "v2",
"created": "Sun, 6 May 2007 15:48:11 GMT"
}
] | 2011-08-11T00:00:00 | [
[
"Buckley",
"M. R.",
""
],
[
"Murayama",
"H.",
""
]
] |
0705.0543 | Aditya Ramamoorthy | Jaehong Kim, Aditya Ramamoorthy and Steven W. McLaughlin | The Design of Efficiently-Encodable Rate-Compatible LDPC Codes | Accepted subject to minor revision to IEEE Trans. on Comm | null | 10.1109/ICC.2006.254899 | null | cs.IT math.IT | null | We present a new class of irregular low-density parity-check (LDPC) codes for
moderate block lengths (up to a few thousand bits) that are well-suited for
rate-compatible puncturing. The proposed codes show good performance under
puncturing over a wide range of rates and are suitable for usage in incremental
redundancy hybrid-automatic repeat request (ARQ) systems. In addition, these
codes are linear-time encodable with simple shift-register circuits. For a
block length of 1200 bits the codes outperform optimized irregular LDPC codes
and extended irregular repeat-accumulate (eIRA) codes for all puncturing rates
0.6~0.9 (base code performance is almost the same) and are particularly good at
high puncturing rates where good puncturing performance has been previously
difficult to achieve.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 22:17:51 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Kim",
"Jaehong",
""
],
[
"Ramamoorthy",
"Aditya",
""
],
[
"McLaughlin",
"Steven W.",
""
]
] |
0705.0544 | R. G. Vishwakarma | R. G. Vishwakarma and J. V. Narlikar | Modeling Repulsive Gravity with Creation | The paper uses an old SNeIa dataset. With the new improved data, for
example the updated gold sample (Riess et al, astro-ph/0611572), the fit
improves considerably (\chi^2/DoF=197/180 and a probability of
goodness-of-fit=18%) | J.Astrophys.Astron.28:17-27,2007 | 10.1007/s12036-007-0003-9 | null | astro-ph | null | There is a growing interest in the cosmologists for theories with negative
energy scalar fields and creation, in order to model a repulsive gravity. The
classical steady state cosmology proposed by Bondi, Gold and Hoyle in 1948, was
the first such theory which used a negative kinetic energy creation field to
invoke creation of matter. We emphasize that creation plays very crucial role
in cosmology and provides a natural explanation to the various explosive
phenomena occurring in local (z<0.1) and extra galactic universe. We exemplify
this point of view by considering the resurrected version of this theory - the
quasi-steady state theory, which tries to relate creation events directly to
the large scale dynamics of the universe and supplies more natural explanations
of the observed phenomena. Although the theory predicts a decelerating universe
at the present era, it explains successfully the recent SNe Ia observations
(which require an accelerating universe in the standard cosmology), as we show
in this paper by performing a Bayesian analysis of the data.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 22:23:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vishwakarma",
"R. G.",
""
],
[
"Narlikar",
"J. V.",
""
]
] |
0705.0545 | Holger Knuth | Michael Flohr, Holger Knuth | On Verlinde-Like Formulas in c_{p,1} Logarithmic Conformal Field
Theories | 39 pages, 8 tables | null | null | ITP-UH-10/07 | math-ph hep-th math.MP math.QA | null | Two different approaches to calculate the fusion rules of the c_{p,1} series
of logarithmic conformal field theories are discussed. Both are based on the
modular transformation properties of a basis of chiral vacuum torus amplitudes,
which contains the characters of the irreducible representations. One of these
is an extension, which we develop here for a non-semisimple generalisation of
the Verlinde formula introduced by Fuchs et al., to include fusion products
with indecomposable representations. The other uses the Verlinde formula in its
usual form and gets the fusion coefficients in the limit, in which the basis of
torus amplitudes degenerates to the linear dependent set of characters of
irreducible and indecomposable representations. We discuss the effects, which
this linear dependence has on any result for fusion rules, which are calculated
from these character's modular transformation properties. We show that the two
presented methods are equivalent. Furthermore we calculate explicit BPZ-like
expressions for the resulting fusion rules for all p larger than 2.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 15:03:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Flohr",
"Michael",
""
],
[
"Knuth",
"Holger",
""
]
] |
0705.0546 | Michael Goldberg | M. Burak Erdogan, Michael Goldberg, Wilhelm Schlag | Strichartz and Smoothing Estimates for Schr\"odinger Operators with
Almost Critical Magnetic Potentials in Three and Higher Dimensions | 36 pages | null | null | null | math.AP | null | In this paper we consider magnetic Schr\"odinger operators in R^n, n \ge 3.
Under almost optimal conditions on the potentials in terms of decay and
regularity we prove smoothing and Strichartz estimates, as well as a limiting
absorption principle. For large gradient perturbations the latter is not a
corollary of the free case as the differentiated free resolvent does not have
small operator norm on any weighted L^2 spaces.
We instead show that the spectral radius of such operators decreases to zero,
hence their perturbation of the identity is still invertible. The key estimates
are based on an angular decomposition of the free resolvent, or rather a bound
that holds uniformly for all possible angular decompositions. The proof avoids
the Fourier transform and instead uses H\"ormander's variable coefficient
Plancherel theorem for oscillatory integrals.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 22:46:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Erdogan",
"M. Burak",
""
],
[
"Goldberg",
"Michael",
""
],
[
"Schlag",
"Wilhelm",
""
]
] |
0705.0547 | Werner D\"appen | Asher Perez, Katie Mussack, Werner Dappen, Dan Mao | The Solar-Interior Equation of State with the Path-Integral Formalism I.
Domain of Validity | Completely rewritten revised version. Accepted for publication in
Astronomy & Astrophysics | null | null | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This is the first paper in a series that deals with solar-physics
applications of the equation-of-state formalism based on the formulation of the
so-called "Feynman-Kac (FK) representation". Here, the FK equation of state is
presented and adapted for solar applications. Its domain of validity is
assessed. The practical application to the Sun will be dealt with in Paper II.
Paper III will extend the current FK formalism to a higher order. Use of the FK
equation of state is limited to physical conditions for which more than 90% of
helium is ionized. This incudes the inner region of the Sun out to about .98 of
the solar radius. Despite this limitation, in the parts of the Sun where it is
applicable, the FK equation of state has the power to be more accurate than the
equations of state currently used in solar modeling. The FK approach is
especially suited to study physical effects such as Coulomb screening, bound
states, the onset of recombination of fully ionized species, as well as
diffraction and exchange effects. The localizing power of helioseismology
allows a test of the FK equation of state. Such a test will be beneficial both
for better solar models and for tighter solar constraints of the equation of
state.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 23:00:47 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Aug 2009 21:46:27 GMT"
}
] | 2009-08-07T00:00:00 | [
[
"Perez",
"Asher",
""
],
[
"Mussack",
"Katie",
""
],
[
"Dappen",
"Werner",
""
],
[
"Mao",
"Dan",
""
]
] |
0705.0548 | Carlos Augusto Romero Filho | Jose Edgar Madriz Aguilar, Carlos Romero and Adriano Barros | Modified Brans-Dicke theory of gravity from five-dimensional vacuum | 9 pages | Gen.Rel.Grav.40:117-130,2008 | 10.1007/s10714-007-0517-0 | null | gr-qc | null | We investigate, in the context of five-dimensional (5D) Brans-Dicke theory of
gravity, the idea that macroscopic matter configurations can be generated from
pure vacuum in five dimensions, an approach first proposed in the framework of
general relativity. We show that the 5D Brans-Dicke vacuum equations when
reduced to four dimensions lead to a modified version of Brans-Dicke theory in
four dimensions (4D). As an application of the formalism, we obtain two
five-dimensional extensions of four-dimensional O'Hanlon and Tupper vacuum
solution and show that they lead two different cosmological scenarios in 4D.
| [
{
"version": "v1",
"created": "Thu, 3 May 2007 23:31:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aguilar",
"Jose Edgar Madriz",
""
],
[
"Romero",
"Carlos",
""
],
[
"Barros",
"Adriano",
""
]
] |
0705.0549 | Bartlomiej Waclaw | L. Bogacz, Z. Burda, W. Janke, and B. Waclaw | Free zero-range processes on networks | 11 pages, 4 figures, to appear in Proceedings of SPIE Symposium
"Fluctuations and Noise 2007", Florence, 20-24 May 2007 | Proceedings of SPIE - Volume 6601, 66010V (2007) | 10.1117/12.726304 | null | cond-mat.stat-mech | null | A free zero-range process (FRZP) is a simple stochastic process describing
the dynamics of a gas of particles hopping between neighboring nodes of a
network. We discuss three different cases of increasing complexity: (a) FZRP on
a rigid geometry where the network is fixed during the process, (b) FZRP on a
random graph chosen from a given ensemble of networks, (c) FZRP on a dynamical
network whose topology continuously changes during the process in a way which
depends on the current distribution of particles. The case (a) provides a very
simple realization of the phenomenon of condensation which manifests as the
appearance of a condensate of particles on the node with maximal degree. The
case (b) is very interesting since the averaging over typical ensembles of
graphs acts as a kind of homogenization of the system which makes all nodes
identical from the point of view of the FZRP. In the case (c), the distribution
of particles and the dynamics of network are coupled to each other. The
strength of this coupling depends on the ratio of two time scales: for changes
of the topology and of the FZRP. We will discuss a specific example of that
type of interaction and show that it leads to an interesting phase diagram.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:48:59 GMT"
}
] | 2007-10-25T00:00:00 | [
[
"Bogacz",
"L.",
""
],
[
"Burda",
"Z.",
""
],
[
"Janke",
"W.",
""
],
[
"Waclaw",
"B.",
""
]
] |
0705.0550 | Eva Silverstein | Daniel Green, Albion Lawrence, John McGreevy, David R. Morrison, and
Eva Silverstein | Dimensional Duality | 25 pages, harvmac. v2: fixed typo. v3: fixed typos and added refs | Phys.Rev.D76:066004,2007 | 10.1103/PhysRevD.76.066004 | NSF-KITP-07-56, SLAC-PUB-12439, SU-ITP-07/05, MIT-CTP 3829,
BRX-TH-586, DUKE-CGTP-07-02, UCSB Math 2007-08 | hep-th | null | We show that string theory on a compact negatively curved manifold,
preserving a U(1)^{b_1} winding symmetry, grows at least b_1 new effective
dimensions as the space shrinks. The winding currents yield a "D-dual"
description of a Riemann surface of genus h in terms of its 2h dimensional
Jacobian torus, perturbed by a closed string tachyon arising as a potential
energy term in the worldsheet sigma model. D-branes on such negatively curved
manifolds also reveal this structure, with a classical moduli space consisting
of a b_1-torus. In particular, we present an AdS/CFT system which offers a
non-perturbative formulation of such supercritical backgrounds. Finally, we
discuss generalizations of this new string duality.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 15:02:58 GMT"
},
{
"version": "v2",
"created": "Tue, 8 May 2007 23:25:06 GMT"
},
{
"version": "v3",
"created": "Mon, 28 May 2007 21:49:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Green",
"Daniel",
""
],
[
"Lawrence",
"Albion",
""
],
[
"McGreevy",
"John",
""
],
[
"Morrison",
"David R.",
""
],
[
"Silverstein",
"Eva",
""
]
] |
0705.0551 | Gerardo Naumis | Gerardo G. Naumis, Germinal Cocho | Tail universalities in rank distributions as an algebraic problem: the
beta-like function | null | Physica A 387, 84-96 (2008) | 10.1016/j.physa.2007.08.002 | null | physics.data-an physics.gen-ph | null | Although power laws of the Zipf type have been used by many workers to fit
rank distributions in different fields like in economy, geophysics, genetics,
soft-matter, networks etc., these fits usually fail at the tails. Some
distributions have been proposed to solve the problem, but unfortunately they
do not fit at the same time both ending tails. We show that many different data
in rank laws, like in granular materials, codons, author impact in scientific
journal, etc. are very well fitted by a beta-like function. Then we propose
that such universality is due to the fact that a system made from many
subsystems or choices, imply stretched exponential frequency-rank functions
which qualitatively and quantitatively can be fitted with the proposed
beta-like function distribution in the limit of many random variables. We prove
this by transforming the problem into an algebraic one: finding the rank of
successive products of a given set of numbers.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 00:11:24 GMT"
}
] | 2015-10-12T00:00:00 | [
[
"Naumis",
"Gerardo G.",
""
],
[
"Cocho",
"Germinal",
""
]
] |
0705.0552 | Rajeev Raman | Rajeev Raman, Venkatesh Raman, Srinivasa Rao Satti | Succinct Indexable Dictionaries with Applications to Encoding $k$-ary
Trees, Prefix Sums and Multisets | Final version of SODA 2002 paper; supersedes Leicester Tech report
2002/16 | ACM Transactions on Algorithms vol 3 (2007), Article 43, 25pp | 10.1145/1290672.1290680 | null | cs.DS cs.DM cs.IT math.IT | null | We consider the {\it indexable dictionary} problem, which consists of storing
a set $S \subseteq \{0,...,m-1\}$ for some integer $m$, while supporting the
operations of $\Rank(x)$, which returns the number of elements in $S$ that are
less than $x$ if $x \in S$, and -1 otherwise; and $\Select(i)$ which returns
the $i$-th smallest element in $S$. We give a data structure that supports both
operations in O(1) time on the RAM model and requires ${\cal B}(n,m) + o(n) +
O(\lg \lg m)$ bits to store a set of size $n$, where ${\cal B}(n,m) = \ceil{\lg
{m \choose n}}$ is the minimum number of bits required to store any $n$-element
subset from a universe of size $m$. Previous dictionaries taking this space
only supported (yes/no) membership queries in O(1) time. In the cell probe
model we can remove the $O(\lg \lg m)$ additive term in the space bound,
answering a question raised by Fich and Miltersen, and Pagh.
We present extensions and applications of our indexable dictionary data
structure, including:
An information-theoretically optimal representation of a $k$-ary cardinal
tree that supports standard operations in constant time,
A representation of a multiset of size $n$ from $\{0,...,m-1\}$ in ${\cal
B}(n,m+n) + o(n)$ bits that supports (appropriate generalizations of) $\Rank$
and $\Select$ operations in constant time, and
A representation of a sequence of $n$ non-negative integers summing up to $m$
in ${\cal B}(n,m+n) + o(n)$ bits that supports prefix sum queries in constant
time.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:47:05 GMT"
}
] | 2011-08-10T00:00:00 | [
[
"Raman",
"Rajeev",
""
],
[
"Raman",
"Venkatesh",
""
],
[
"Satti",
"Srinivasa Rao",
""
]
] |
0705.0553 | Mark Stockman | Xiangting Li and Mark I. Stockman | Time-Reversal Coherent Control in Nanoplasmonics | 5 pages, 4 figures | null | null | null | cond-mat.dis-nn cond-mat.mtrl-sci | null | We introduce an approach to determining the required waveforms to coherently
control the optical energy localization in plasmonic nanosystems. This approach
is based on the impulsive localized excitation of the nanosystem and time
reversal of the generated far-zone field at a single point with one
polarization. Despite strong interaction and significant dephasing and
dissipation in metal plasmonic systems, and incompleteness of this time
reversal, the proposed approach proves to be very efficient in controlling the
nanoscale optical fields. Possible applications include nanoscale spectroscopy
and photomodification, ultradense memory, and information processing on the
nanoscale.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 01:19:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Li",
"Xiangting",
""
],
[
"Stockman",
"Mark I.",
""
]
] |
0705.0554 | Jennifer Kile | Jennifer Kile, Michael J. Ramsey-Musolf | Fermionic Effective Operators and Higgs Production at a Linear Collider | 25 pages, 9 figures, fixed typo in author names | Phys.Rev.D76:054009,2007 | 10.1103/PhysRevD.76.054009 | Caltech MAP-332, CALT-68-2648 | hep-ph | null | We study the possible contributions of dimension six operators containing
fermion fields to Higgs production at a 500 GeV or 1 TeV $e^+e^-$ linear
collider. We show that -- depending on the production mechanism -- the effects
of such operators can be kinematically enhanced relative to Standard Model (SM)
contributions. We determine constraints on the operator coefficients implied by
existing precision electroweak measurements and the scale of neutrino mass. We
find that even in the presence of such constraints, substantial deviations from
SM Higgs production cross-sections are possible. We compare the effects of
fermionic operators with those associated with purely bosonic operators that
have been previously discussed in the literature.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 01:07:32 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 00:12:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kile",
"Jennifer",
""
],
[
"Ramsey-Musolf",
"Michael J.",
""
]
] |
0705.0555 | Vitalii Vlasko-Vlasov K | V.Vlasko-Vlasov, U.Welp, G.Karapetrov, V.Novosad, A.Belkin,
D.Rosenmann, M. Iavarone, W. -K. Kwok | Guiding superconducting vortices by magnetic domain walls | 12 pages, 6 figures | null | 10.1103/PhysRevB.77.134518 | null | cond-mat.supr-con cond-mat.mtrl-sci | null | We demonstrate a unique prospect for inducing anisotropic vortex pinning and
manipulating the directional motion of vortices using the stripe domain
patterns of a uniaxial magnetic film in a the superconducting/ferromagnetic
hybrid. Our observations can be described by a model, which considers
interactions between magnetic charges of vortices and surface magnetic charges
of domains resulting in the enhanced pinning of vortices on domain walls.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 00:56:39 GMT"
},
{
"version": "v2",
"created": "Thu, 10 May 2007 20:26:51 GMT"
},
{
"version": "v3",
"created": "Tue, 29 Jan 2008 04:37:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vlasko-Vlasov",
"V.",
""
],
[
"Welp",
"U.",
""
],
[
"Karapetrov",
"G.",
""
],
[
"Novosad",
"V.",
""
],
[
"Belkin",
"A.",
""
],
[
"Rosenmann",
"D.",
""
],
[
"Iavarone",
"M.",
""
],
[
"Kwok",
"W. -K.",
""
]
] |
0705.0556 | Gengchiau Liang | Gengchiau Liang, Neophytos Neophytou, Mark S. Lundstrom, and Dmitri E.
Nikonov | Ballistic Graphene Nanoribbon MOSFETs: a full quantum real-space
simulation study | null | null | null | null | cond-mat.mes-hall | null | A real-space quantum transport simulator for carbon nanoribbon (CNR) MOSFETs
has been developed. Using this simulator, the performance of carbon nanoribbon
(CNR) MOSFETs is examined in the ballistic limit. The impact of quantum effects
on device performance of CNR MOSFETs is also studied. We found that 2D
semi-infinite graphene contacts provide metal-induced-gap-states (MIGS) in the
CNR channel. These states would provide quantum tunneling in the short channel
device and cause Fermi level pining. These effects cause device performance
degradation both on the ON-state and the OFF-state. Pure 1D devices (infinite
contacts), however, show no MIGS. Quantum tunneling effects are still playing
an important role in the device characteristics. Conduction due to band-to-band
tunneling is accurately captured in our simulations. It is important in these
devices, and found to dominate the off-state current. Based on our simulations,
both a 1.4nm wide and a 1.8nm wide CNR with channel length of 12.5nm can
outperform ultra scaled Si devices in terms of drive current capabilities and
electrostatic control. Although subthreshold slopes in the forward-bias
conduction are better than in Si transistors, tunneling currents are important
and prevent the achievement of the theoretical limit of 60mV/dec.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 01:07:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Liang",
"Gengchiau",
""
],
[
"Neophytou",
"Neophytos",
""
],
[
"Lundstrom",
"Mark S.",
""
],
[
"Nikonov",
"Dmitri E.",
""
]
] |
0705.0557 | Nicholas S. Witte | N.S. Witte | Isomonodromic deformation theory and the next-to-diagonal correlations
of the anisotropic square lattice Ising model | 11 pages, 1 figure | J.Phys.A40:F491,2007 | 10.1088/1751-8113/40/24/F08 | null | math-ph math.CA math.MP | null | In 1980 Jimbo and Miwa evaluated the diagonal two-point correlation function
of the square lattice Ising model as a $\tau$-function of the sixth Painlev\'e
system by constructing an associated isomonodromic system within their theory
of holonomic quantum fields. More recently an alternative isomonodromy theory
was constructed based on bi-orthogonal polynomials on the unit circle with
regular semi-classical weights, for which the diagonal Ising correlations arise
as the leading coefficient of the polynomials specialised appropriately. Here
we demonstrate that the next-to-diagonal correlations of the anisotropic Ising
model are evaluated as one of the elements of this isomonodromic system or
essentially as the Cauchy-Hilbert transform of one of the bi-orthogonal
polynomials.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 01:11:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Witte",
"N. S.",
""
]
] |
0705.0558 | Martino Poggio | M. Poggio, C. L. Degen, C. T. Rettner, H. J. Mamin, and D. Rugar | Nuclear magnetic resonance force microscopy with a microwire rf source | 4 pages, 4 figures | Appl. Phys. Lett. 90, 263111 (2007) | 10.1063/1.2752536 | null | cond-mat.other | null | We use a 1.0-um-wide patterned Cu wire with an integrated nanomagnetic tip to
measure the statistical nuclear polarization of 19F in CaF2 by magnetic
resonance force microscopy (MRFM). With less than 350 uW of dissipated power,
we achieve rf magnetic fields over 4 mT at 115 MHz for a sample positioned
within 100 nm of the "microwire" rf source. A 200-nm diameter FeCo tip
integrated onto the wire produces field gradients greater than 10^5 T/m at the
same position. The large rf fields from the broadband microwire enable long
rotating-frame spin lifetimes of up to 15 s at 4 K.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 01:25:47 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 17:46:44 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Poggio",
"M.",
""
],
[
"Degen",
"C. L.",
""
],
[
"Rettner",
"C. T.",
""
],
[
"Mamin",
"H. J.",
""
],
[
"Rugar",
"D.",
""
]
] |
0705.0559 | Gilberto C. G\'omez | Gilberto C. G\'omez, Enrique V\'azquez-Semadeni, Mohsen Shadmehri and
Javier Ballesteros-Paredes | Formation and Collapse of Quiescent Cloud Cores Induced by Dynamic
Compressions | Accepted for publication in ApJ. Associated mpeg files can be found
in http://www.astrosmo.unam.mx/~g.gomez/publica.html | null | 10.1086/521620 | null | astro-ph | null | (Abridged) We present numerical hydrodynamical simulations of the formation,
evolution and gravitational collapse of isothermal molecular cloud cores. A
compressive wave is set up in a constant sub-Jeans density distribution of
radius r = 1 pc. As the wave travels through the simulation grid, a
shock-bounded spherical shell is formed. The inner shock of this shell reaches
and bounces off the center, leaving behind a central core with an initially
almost uniform density distribution, surrounded by an envelope consisting of
the material in the shock-bounded shell, with a power-law density profile that
at late times approaches a logarithmic slope of -2 even in non-collapsing
cases. The resulting density structure resembles a quiescent core of radius <
0.1 pc, with a Bonnor-Ebert-like (BE-like) profile, although it has significant
dynamical differences: it is initially non-self-gravitating and confined by the
ram pressure of the infalling material, and consequently, growing continuously
in mass and size. With the appropriate parameters, the core mass eventually
reaches an effective Jeans mass, at which time the core begins to collapse.
Thus, there is necessarily a time delay between the appearance of the core and
the onset of its collapse, but this is not due to the dissipation of its
internal turbulence as it is often believed. These results suggest that
pre-stellar cores may approximate Bonnor-Ebert structures which are however of
variable mass and may or may not experience gravitational collapse, in
qualitative agreement with the large observed frequency of cores with BE-like
profiles.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 01:27:05 GMT"
},
{
"version": "v2",
"created": "Mon, 13 Aug 2007 17:36:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gómez",
"Gilberto C.",
""
],
[
"Vázquez-Semadeni",
"Enrique",
""
],
[
"Shadmehri",
"Mohsen",
""
],
[
"Ballesteros-Paredes",
"Javier",
""
]
] |
0705.0560 | Harry Kojima | Y. Aoki, J.C. Graves and H. Kojima | Oscillation Frequency Dependence of Non-Classical Rotation Inertia of
Solid $^4$He | 4 pages, 4 figures | null | 10.1103/PhysRevLett.99.015301 | null | cond-mat.other cond-mat.stat-mech | null | The non-classical rotational inertia fraction of the identical cylindrical
solid $^4$He below 300 mK is studied at 496 and 1173 Hz by a double resonance
torsional oscillator. Below 35 mK, the fraction is the same at sufficiently low
rim velocities. Above 35 mK, the fraction is greater for the higher than the
lower mode. The dissipation peak of the lower mode occurs at a temperature
$\sim$ 4 mK lower than that of the higher mode. The drive dependence of the two
modes shows that the reduction of the fraction is characterized by critical
velocity, \textit{not} amplitude nor acceleration.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 13:04:08 GMT"
},
{
"version": "v2",
"created": "Mon, 7 May 2007 15:39:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Aoki",
"Y.",
""
],
[
"Graves",
"J. C.",
""
],
[
"Kojima",
"H.",
""
]
] |
0705.0561 | Jingchao Chen | Jing-Chao Chen | Iterative Rounding for the Closest String Problem | This paper has been published in abstract Booklet of CiE09 | null | null | null | cs.DS cs.CC | http://creativecommons.org/licenses/by-nc-sa/3.0/ | The closest string problem is an NP-hard problem, whose task is to find a
string that minimizes maximum Hamming distance to a given set of strings. This
can be reduced to an integer program (IP). However, to date, there exists no
known polynomial-time algorithm for IP. In 2004, Meneses et al. introduced a
branch-and-bound (B & B) method for solving the IP problem. Their algorithm is
not always efficient and has the exponential time complexity. In the paper, we
attempt to solve efficiently the IP problem by a greedy iterative rounding
technique. The proposed algorithm is polynomial time and much faster than the
existing B & B IP for the CSP. If the number of strings is limited to 3, the
algorithm is provably at most 1 away from the optimum. The empirical results
show that in many cases we can find an exact solution. Even though we fail to
find an exact solution, the solution found is very close to exact solution.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 03:01:42 GMT"
},
{
"version": "v2",
"created": "Wed, 11 May 2011 00:18:55 GMT"
}
] | 2011-05-12T00:00:00 | [
[
"Chen",
"Jing-Chao",
""
]
] |
0705.0562 | Juan-Pablo Ortega | Rui Loja Fernandes, Juan-Pablo Ortega, Tudor S. Ratiu | The momentum map in Poisson geometry | 34 pages; to appear in American Journal of Mathematics | null | null | null | math.SG math.DG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Every action on a Poisson manifold by Poisson diffeomorphisms lifts to a
Hamiltonian action on its symplectic groupoid which has a canonically defined
momentum map. We study various properties of this momentum map as well as its
use in reduction.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 18:55:34 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Sep 2008 12:17:18 GMT"
},
{
"version": "v3",
"created": "Mon, 2 Mar 2009 10:11:30 GMT"
}
] | 2009-03-02T00:00:00 | [
[
"Fernandes",
"Rui Loja",
""
],
[
"Ortega",
"Juan-Pablo",
""
],
[
"Ratiu",
"Tudor S.",
""
]
] |
0705.0563 | Naruhiko Aizawa | N. Aizawa and R. Chakrabarti | Fuzzy Torus via q-Parafermion | 12pages, no figure | J.Phys.A40:10021-10030,2007 | 10.1088/1751-8113/40/33/007 | null | hep-th | null | We note that the recently introduced fuzzy torus can be regarded as a
q-deformed parafermion. Based on this picture, classification of the Hermitian
representations of the fuzzy torus is carried out. The result involves
Fock-type representations and new finite dimensional representations for q
being a root of unity as well as already known finite dimensional ones.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 06:18:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aizawa",
"N.",
""
],
[
"Chakrabarti",
"R.",
""
]
] |
0705.0564 | Caleb Lo | Caleb K. Lo, Sriram Vishwanath and Robert W. Heath Jr | Rate Bounds for MIMO Relay Channels | 25 pages, 6 figures, submitted to Journal on Communications and
Networks in December 2007, revised in April 2008 | null | null | null | cs.IT math.IT | null | This paper considers the multi-input multi-output (MIMO) relay channel where
multiple antennas are employed by each terminal. Compared to single-input
single-output (SISO) relay channels, MIMO relay channels introduce additional
degrees of freedom, making the design and analysis of optimal cooperative
strategies more complex. In this paper, a partial cooperation strategy that
combines transmit-side message splitting and block-Markov encoding is
presented. Lower bounds on capacity that improve on a previously proposed
non-cooperative lower bound are derived for Gaussian MIMO relay channels.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 06:43:42 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Dec 2007 17:39:33 GMT"
},
{
"version": "v3",
"created": "Thu, 10 Apr 2008 15:52:35 GMT"
},
{
"version": "v4",
"created": "Fri, 2 May 2008 21:33:42 GMT"
}
] | 2008-05-03T00:00:00 | [
[
"Lo",
"Caleb K.",
""
],
[
"Vishwanath",
"Sriram",
""
],
[
"Heath",
"Robert W.",
"Jr"
]
] |
0705.0565 | Sachiko Takeuchi | Sachiko Takeuchi and Kiyotaka Shimizu | Lambda(1405) as a Resonance in the Baryon-Meson Scattering Coupled to
the q^3 State in a Quark Model | 16 pages and 7 figures | Phys.Rev.C76:035204,2007 | 10.1103/PhysRevC.76.035204 | null | hep-ph | null | In order to describe Lambda(1405) as a resonance in the baryon-meson
scattering, we have investigated q^3-q qbar scattering system with the
flavor-singlet q^3 (0s)^2(0p) state (the Lambda^1 pole). The scattering is
treated by the quark cluster model (QCM). The Lambda^1 pole is treated as a
bound state embedded in the continuum. We found that the peak appears below the
N Kbar threshold in the spin one half, isospin 0 channel even if the mass of
the Lambda^1 pole is above the threshold. This peak disappears when the
coupling to the Lambda^1 pole is switched off. To use the observed hadron mass
in the kinetic part of QCM is also found to be important to reproduce a peak
just below the N Kbar threshold.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:04:38 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Takeuchi",
"Sachiko",
""
],
[
"Shimizu",
"Kiyotaka",
""
]
] |
0705.0566 | Thibaut Devillers | Thibaut Devillers (DRFMC/SP2M), Matthieu Jamet (DRFMC/SP2M), Andr\'e
Barski (DRFMC/SP2M), Valier Poydenot (DRFMC/SP2M), Pascale Bayle-Guillemaud
(DRFMC/SP2M), Edith Bellet-Amalric (DRFMC/SP2M), Salia Cherifi (NEEL), Jo\"el
Cibert (NEEL) | Structure and magnetism of self-organized Ge(1-x)Mn(x) nano-columns | 10 pages 2 colonnes revTex formatted | Physical Review B 76 (2007) 205306 | 10.1103/PhysRevB.76.205306 | null | cond-mat.mtrl-sci | null | We report on the structural and magnetic properties of thin Ge(1-x)Mn(x)films
grown by molecular beam epitaxy (MBE) on Ge(001) substrates at temperatures
(Tg) ranging from 80deg C to 200deg C, with average Mn contents between 1 % and
11 %. Their crystalline structure, morphology and composition have been
investigated by transmission electron microscopy (TEM), electron energy loss
spectroscopy and x-ray diffraction. In the whole range of growth temperatures
and Mn concentrations, we observed the formation of manganese rich
nanostructures embedded in a nearly pure germanium matrix. Growth temperature
mostly determines the structural properties of Mn-rich nanostructures. For low
growth temperatures (below 120deg C), we evidenced a two-dimensional spinodal
decomposition resulting in the formation of vertical one-dimensional
nanostructures (nanocolumns). Moreover we show in this paper the influence of
growth parameters (Tg and Mn content) on this decomposition i.e. on nanocolumns
size and density. For temperatures higher than 180deg C, we observed the
formation of Ge3Mn5 clusters. For intermediate growth temperatures nanocolumns
and nanoclusters coexist. Combining high resolution TEM and superconducting
quantum interference device magnetometry, we could evidence at least four
different magnetic phases in Ge(1-x)Mn(x) films: (i) paramagnetic diluted Mn
atoms in the germanium matrix, (ii) superparamagnetic and ferromagnetic low-Tc
nanocolumns (120 K < Tc < 170 K), (iii) high-Tc nanocolumns (Tc> 400 K) and
(iv) Ge3Mn5 clusters.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:14:12 GMT"
}
] | 2008-09-05T00:00:00 | [
[
"Devillers",
"Thibaut",
"",
"DRFMC/SP2M"
],
[
"Jamet",
"Matthieu",
"",
"DRFMC/SP2M"
],
[
"Barski",
"André",
"",
"DRFMC/SP2M"
],
[
"Poydenot",
"Valier",
"",
"DRFMC/SP2M"
],
[
"Bayle-Guillemaud",
"Pascale",
"",
"DRFMC/SP2M"
],
[
"Bellet-Amalric",
"Edith",
"",
"DRFMC/SP2M"
],
[
"Cherifi",
"Salia",
"",
"NEEL"
],
[
"Cibert",
"Joël",
"",
"NEEL"
]
] |
0705.0567 | Claude Billionnet | Claude Billionnet (CPHT) | Influence of the extent of the eigenstates of a system on the resonances
formed through its coupling to a field | null | null | null | null | physics.flu-dyn hep-th math-ph math.MP quant-ph | null | We examine resonances for two systems consisting of a particle coupled to a
massless boson's field. The field is the free field in the whole space. In the
first system, the particle is confined inside a ball. We show that besides the
usual energy levels of the particle, which have become complex through the
coupling to the field, other resonances are to be taken into account if the
ball's radius is comparable to the particle's Compton wavelength. In the second
system, the particle is in a finite-depth square-well potential. We study the
way the resonances' width depends on the extent of the uncoupled particle's
wave functions. In both cases, we limit ourselves to considering two levels of
the particle only.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:15:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Billionnet",
"Claude",
"",
"CPHT"
]
] |
0705.0568 | Rodolphe Thiebaut | Rodolphe Thi\'ebaut, H\'el\`ene Jacqmin-Gadda, Genevi\`eve Ch\^ene,
Catherine Leport, Daniel Commenges | Bivariate linear mixed models using SAS proc MIXED | null | Comput Methods Programs Biomed 69, 3 (11/2002) 249-56 | null | null | stat.AP stat.ME | null | Bivariate linear mixed models are useful when analyzing longitudinal data of
two associated markers. In this paper, we present a bivariate linear mixed
model including random effects or first-order auto-regressive process and
independent measurement error for both markers. Codes and tricks to fit these
models using SAS Proc MIXED are provided. Limitations of this program are
discussed and an example in the field of HIV infection is shown. Despite some
limitations, SAS Proc MIXED is a useful tool that may be easily extendable to
multivariate response in longitudinal studies.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:21:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Thiébaut",
"Rodolphe",
""
],
[
"Jacqmin-Gadda",
"Hélène",
""
],
[
"Chêne",
"Geneviève",
""
],
[
"Leport",
"Catherine",
""
],
[
"Commenges",
"Daniel",
""
]
] |
0705.0569 | Rodolphe Thiebaut | Rodolphe Thi\'ebaut, H\'el\`ene Jacqmin-Gadda | Mixed models for longitudinal left-censored repeated measures | null | Comput Methods Programs Biomed 74, 3 (06/2004) 255-60 | 10.1016/j.cmpb.2003.08.004 | null | stat.AP | null | Longitudinal studies could be complicated by left-censored repeated measures.
For example, in Human Immunodeficiency Virus infection, there is a detection
limit of the assay used to quantify the plasma viral load. Simple imputation of
the limit of the detection or of half of this limit for left-censored measures
biases estimations and their standard errors. In this paper, we review two
likelihood-based methods proposed to handle left-censoring of the outcome in
linear mixed model. We show how to fit these models using SAS Proc NLMIXED and
we compare this tool with other programs. Indications and limitations of the
programs are discussed and an example in the field of HIV infection is shown.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:24:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Thiébaut",
"Rodolphe",
""
],
[
"Jacqmin-Gadda",
"Hélène",
""
]
] |
0705.0570 | Ivan Nourdin | Ivan Nourdin | Asymptotic behavior of weighted quadratic and cubic variations of
fractional Brownian motion | Published in at http://dx.doi.org/10.1214/07-AOP385 the Annals of
Probability (http://www.imstat.org/aop/) by the Institute of Mathematical
Statistics (http://www.imstat.org) | Annals of Probability 2008, Vol. 36, No. 6, 2159-2175 | 10.1214/07-AOP385 | IMS-AOP-AOP385 | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The present article is devoted to a fine study of the convergence of
renormalized weighted quadratic and cubic variations of a fractional Brownian
motion $B$ with Hurst index $H$. In the quadratic (resp. cubic) case, when
$H<1/4$ (resp. $H<1/6$), we show by means of Malliavin calculus that the
convergence holds in $L^2$ toward an explicit limit which only depends on $B$.
This result is somewhat surprising when compared with the celebrated Breuer and
Major theorem.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 07:28:47 GMT"
},
{
"version": "v2",
"created": "Sat, 5 May 2007 10:28:59 GMT"
},
{
"version": "v3",
"created": "Sat, 21 Jul 2007 17:16:16 GMT"
},
{
"version": "v4",
"created": "Mon, 19 Jan 2009 15:54:05 GMT"
}
] | 2009-01-19T00:00:00 | [
[
"Nourdin",
"Ivan",
""
]
] |
0705.0571 | Alexander Andreev | A.F.Andreev | Supersolidity of glasses | 5 pages, no figures | null | null | null | cond-mat.soft cond-mat.dis-nn cond-mat.stat-mech | null | Supersolidity of glasses is explained as a property of an unusual state of
condensed matter. This state is essentially different from both normal and
superfluid solid states. The mechanism of the phenomenon is the transfer of
mass by tunneling two level systems.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 08:04:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Andreev",
"A. F.",
""
]
] |
0705.0572 | Andr\'e Walker-Loud | Kostas Orginos, Andre Walker-Loud | Mixed Meson Masses with Domain-Wall Valence and Staggered Sea Fermions | 28 pages, 3 figures, 5 tables | Phys.Rev.D77:094505,2008 | 10.1103/PhysRevD.77.094505 | JLAB-THY-07-638, UMD-40762-385 | hep-lat | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Mixed action lattice calculations allow for an additive lattice spacing
dependent mass renormalization of mesons composed of one sea and one valence
quark, regardless of the type of fermion discretization methods used in the
valence and sea sectors. The value of the mass renormalization depends upon the
lattice actions used. This mixed meson mass shift is an important lattice
artifact to determine for mixed action calculations; because it modifies the
pion mass, it plays a central role in the low energy dynamics of all hadronic
correlation functions. We determine the leading order, $\mathcal{O}(a^2)$, and
next to leading order, $\mathcal{O}(a^2 m_\pi^2)$, additive mass shift of
\textit{valence-sea} mesons for a mixed lattice action with domain-wall valence
fermions and rooted staggered sea fermions, relevant to the majority of current
large scale mixed action lattice efforts. We find that on the asqtad improved
coarse MILC lattices, this additive mass shift is well parameterized in lattice
units by $\Delta(am)^2 = 0.034(2) -0.06(2) (a m_\pi)^2$, which in physical
units, using $a=0.125$ fm, corresponds to $\Delta(m)^2 = (291\pm 8
\textrm{MeV})^2 -0.06(2) m_\pi^2$. In terms of the mixed action effective field
theory parameters, the corresponding mass shift is given by $a^2
\Delta_\mathrm{Mix} = (316 \pm 4 \textrm{MeV})^2$ at leading order plus
next-to-leading order corrections including the necessary chiral logarithms for
this mixed action calculation, determined in this work. Within the precision of
our calculation, one can not distinguish between the full next-to-leading order
effective field theory analysis of this additive mixed meson mass shift and the
parameterization given above.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 19:46:45 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jun 2008 19:17:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Orginos",
"Kostas",
""
],
[
"Walker-Loud",
"Andre",
""
]
] |
0705.0573 | Adam Doliwa | A. Doliwa, M. Nieszporski, and P. M. Santini | Integrable lattices and their sublattices II. From the B-quadrilateral
lattice to the self-adjoint schemes on the triangular and the honeycomb
lattices | 15 pages, 6 figures; references added, some typos corrected | J. Math. Phys. 48 (2007) 113506 | 10.1063/1.2803504 | null | nlin.SI | null | An integrable self-adjoint 7-point scheme on the triangular lattice and an
integrable self-adjoint scheme on the honeycomb lattice are studied using the
sublattice approach. The star-triangle relation between these systems is
introduced, and the Darboux transformations for both linear problems from the
Moutard transformation of the B-(Moutard) quadrilateral lattice are obtained. A
geometric interpretation of the Laplace transformations of the self-adjoint
7-point scheme is given and the corresponding novel integrable discrete 3D
system is constructed.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:22:09 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 07:47:10 GMT"
}
] | 2010-04-19T00:00:00 | [
[
"Doliwa",
"A.",
""
],
[
"Nieszporski",
"M.",
""
],
[
"Santini",
"P. M.",
""
]
] |
0705.0574 | Manuela Magliocchetti | M. Magliocchetti and M. Bruggen | The interplay between radio galaxies and cluster environment | 17 pages, 14 figures, to appear in MNRAS | Mon.Not.Roy.Astron.Soc.379:260-274,2007 | 10.1111/j.1365-2966.2007.11939.x | null | astro-ph | null | By combining the REFLEX and NORAS cluster datasets with the NVSS radio
catalogue, we obtain a sample of 145, z<0.3, X-ray selected clusters brighter
than 3 10^(-12) erg/s/cm^2 that show a central radio emission above 3 mJy. For
virial masses M_vir<~10^(14.5) M_sun, 11 clusters out of 12 (corresponding to
92% of the systems) are inhabited by a central radio source. This fraction
decreases with higher masses as M_vir^(-0.4) and suggests that the majority of
X-ray selected clusters host in their centre a radio source brighter than about
10^(20) W/Hz/sr. A division of the sample into clusters harbouring either
point-like or an extended radio-loud AGN reveals that the steepening of the
L_X-T relation for low-temperature clusters is strongly associated with the
presence of central radio objects with extended jets and/or lobe structures. In
the latter case, L_X\propto T^(4) while for point-like sources one recovers an
approximately self-similar relation L_X\propto T^(2.3). Monte Carlo simulations
show that the steepening of the L_X-T relation is not caused by clusters being
under-luminous in the X-ray band, but rather by overheating, most likely caused
by the interplay between the extended radio structures and the intracluster
medium. In the case of low-mass systems, we also find a tight correlation
between radio luminosity and cluster temperature. The effects of the central
radio source on the thermal state of a cluster become less important with
increasing cluster mass. (Abridged) The luminosity distribution of the cluster
radio population differs from that of all radio sources, as there is a deficit
of low-luminosity (L_R<~10^(22) W/Hz/sr) objects, while the number of
high-luminosity ones is boosted. The net effect on the radio luminosity
function is of a flattening at all luminosities L_R<~ 10^(24) W/Hz/sr.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:07:58 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Magliocchetti",
"M.",
""
],
[
"Bruggen",
"M.",
""
]
] |
0705.0575 | Antonio Siber | Antonio Siber | Continuum and all-atom description of the energetics of graphene
nanocones | Sent to publication | Nanotechnology 18, 375705 (2007) | 10.1088/0957-4484/18/37/375705 | null | cond-mat.mtrl-sci | null | Energies of graphene nanocones with 1 to 5 pentagonal disclinations are
studied on an atomically detailed level. The numerical results are interpreted
in terms of three different contributions to the cone energy: the core
disclination energy, the bending energy of the cone surface, and the ''line
tension'' energy of the cone edge that is related to different coordination of
carbon atoms situated at the edge. This continuum description allows for a
construction of analytic expressions for the cone energetics and indicates
different regimes of cone sizes in which cones with a particular number of
disclinations are preferred energywise. An important result of the study is
that the energetics of various types of cones profoundly depends upon whether
the dangling carbon bonds at the cone basis are saturated by hydrogen atoms or
not. This may be of use for explaining the differences in the yields of various
cone types in different production processes.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:15:32 GMT"
}
] | 2007-08-23T00:00:00 | [
[
"Siber",
"Antonio",
""
]
] |
0705.0576 | Christoph Haefeli | Christoph Haefeli, Mikhail A. Ivanov, Martin Schmid, Gerhard Ecker | On the mesonic Lagrangian of order p^6 in chiral SU(2) | Revtex, 2 pages | null | null | null | hep-ph | null | We show that the number of operators in the presently known mesonic chiral
Lagrangian of order p^6 in the two-flavour sector can be reduced by at least
one from 57 to 56 by providing an explicit relation among the operators. We
briefly discuss the relevance of this new relation.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:28:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Haefeli",
"Christoph",
""
],
[
"Ivanov",
"Mikhail A.",
""
],
[
"Schmid",
"Martin",
""
],
[
"Ecker",
"Gerhard",
""
]
] |
0705.0577 | Rustem Khasanov | R. Khasanov, A. Shengelaya, A. Bussmann-Holder, J. Karpinski, H.
Keller, and K.A. M\"uller | s-wave symmetry along the c-axis and s+d in-plane superconductivity in
bulk YBa_2Cu_4O_8 | 5 pages, 2 figures | Journal of Superconductivity and Novel Magnetism 21, 1557 (2008) | null | null | cond-mat.supr-con | null | To clarify the order parameter symmetry of cuprates, the magnetic penetration
depth $\lambda$ was measured along the crystallographic directions $a$, $b$,
and $c$ in single crystals of YBa$_2$Cu$_4$O$_8$ via muon spin rotation. This
method is direct, bulk sensitive, and unambiguous. The temperature dependences
of $\lambda_a^{-2}$ and $\lambda_b^{-2}$ exhibit an inflection point at low
temperatures as is typical for two-gap superconductivity (TGS) with $s+d-$wave
character in the planes. Perpendicular to the planes a pure s-wave gap is
observed thereby highlighting the important role of c-axis effects. We conclude
that these are generic and universal features in the bulk of cuprates.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:28:59 GMT"
}
] | 2008-10-08T00:00:00 | [
[
"Khasanov",
"R.",
""
],
[
"Shengelaya",
"A.",
""
],
[
"Bussmann-Holder",
"A.",
""
],
[
"Karpinski",
"J.",
""
],
[
"Keller",
"H.",
""
],
[
"Müller",
"K. A.",
""
]
] |
0705.0578 | Istvan Nandori | I. Nandori, K. Vad, S. Meszaros, U. D. Jentschura, S. Nagy, K. Sailer | Applicability of layered sine-Gordon models to layered superconductors:
II. The case of magnetic coupling | 7 pages, 1 figure, published in J. Phys.: Condens. Matter | J. Phys.: Condens. Matter 19 (2007) 496211 | 10.1088/0953-8984/19/49/496211 | null | cond-mat.supr-con cond-mat.str-el | null | In this paper, we propose a quantum field theoretical renormalization group
approach to the vortex dynamics of magnetically coupled layered
superconductors, to supplement our earlier investigations on the
Josephson-coupled case. We construct a two-dimensional multi-layer sine-Gordon
type model which we map onto a gas of topological excitations. With a special
choice of the mass matrix for our field theoretical model, vortex dominated
properties of magnetically coupled layered superconductors can be described.
The well known interaction potentials of fractional flux vortices are
consistently obtained from our field-theoretical analysis, and the physical
parameters (vortex fugacity and temperature parameter) are also identified. We
analyse the phase structure of the multi-layer sine--Gordon model by a
differential renormalization group method for the magnetically coupled case
from first principles. The dependence of the transition temperature on the
number of layers is found to be in agreement with known results based on other
methods.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:29:25 GMT"
},
{
"version": "v2",
"created": "Thu, 24 May 2007 17:15:31 GMT"
},
{
"version": "v3",
"created": "Thu, 22 Nov 2007 08:53:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nandori",
"I.",
""
],
[
"Vad",
"K.",
""
],
[
"Meszaros",
"S.",
""
],
[
"Jentschura",
"U. D.",
""
],
[
"Nagy",
"S.",
""
],
[
"Sailer",
"K.",
""
]
] |
0705.0579 | Fuminobu Takahashi | Fuminobu Takahashi | Gravitino Dark Matter from Inflaton Decay | 16 pages, 3 figures. v2: references and figures added | Phys.Lett.B660:100-106,2008 | 10.1016/j.physletb.2007.12.048 | DESY 07-060 | hep-ph astro-ph hep-th | null | We discuss a scenario that gravitinos produced non-thermally by an inflaton
decay constitute dark matter in the present universe. We find that this
scenario is realized for wide ranges of the inflaton mass and the vacuum
expectation value. What is intriguing about this scenario is that the gravitino
dark matter can have a relatively large free streaming length at
matter-radiation equality, which can be probed by future observation on
QSO-galaxy strong lens system.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 18:51:54 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 15:04:38 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Takahashi",
"Fuminobu",
""
]
] |
0705.0580 | Parongama Sen | Kamalika Basu Hajra and Parongama Sen | Effect of a static phase transition on searching dynamics | 7 pages, 8 figures | null | null | null | cond-mat.stat-mech cond-mat.soft | null | We consider a one dimensional Euclidean network which is grown using a
preferential attachment. Here the $j$th incoming node gets attached to the
$i$th existing node with the probability $\Pi_i \propto k_i {{l}}_{ij}^\alpha$,
where ${l}_{ij}$ is the Euclidean distance between them and $k_i$ the degree of
the $i$th node. This network is known to have a static phase transition point
at $\alpha_c \simeq 0.5$. On this network, we employ three different searching
strategies based on degrees or distances or both, where the possibility of
termination of search chains is allowed. A detailed analysis shows that these
strategies are significantly affected by the presence of the static critical
point. The distributions of the search path lengths and the success rates are
also estimated and compared for the different strategies. These distributions
appear to be marginally affected by the static phase transition.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:09:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hajra",
"Kamalika Basu",
""
],
[
"Sen",
"Parongama",
""
]
] |
0705.0581 | Yoshiro Kakehashi | Yoshiro Kakehashi and Peter Fulde | Nonlocal Excitation Spectra in 2D Doped Hubbard Model | 12 pages, 23 figures | null | 10.1143/JPSJ.76.074702 | null | cond-mat.str-el | null | Single-particle excitation spectra of the two-dimensional Hubbard model on
the square lattice near half filling and at zero temperature are investigated
on the basis of the self-consistent projection operator method. The method
guarantees a high accuracy of the spectra with high energy and high momentum
resolutions. It takes into account long-range intersite correlations as well as
the strong on-site correlations. Effects of nonlocal excitations are clarified
by comparing the results with those of the single-site approximation. The
calculated spectra verify the quantum Monte-Carlo results for finite
temperatures. The spectra at the Fermi level yield a hole-like Fermi surface in
the underdoped region and an electron-like Fermi surface in the overdoped
region. From a numerical analysis of the momentum dependent effective mass and
self-energy, it is concluded that a marginal Fermi-liquid like state persists
even at finite doping concentrations in the strongly correlated region because
a van Hove singularity is pinned to the Fermi surface. It is also found that a
kink structure appears in the quasiparticle energy band in the same region. The
kink is shown to be caused by a mixing between the quasiparticle band and an
excitation band with strong short-range antiferromagnetic correlations. These
results suggest an explanation for some of the unusual properties of the normal
state in high-$T_{\rm c}$ cuprates.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:48:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kakehashi",
"Yoshiro",
""
],
[
"Fulde",
"Peter",
""
]
] |
0705.0582 | Jes\'us Casado Pascual | Jes\'us Casado-Pascual (1), David Cubero (1), Jos\'e Pablo Baltan\'as
(2) ((1) F\'isica Te\'orica, Universidad de Sevilla, Spain, (2) Departamento
de F\'isica Aplicada II, Universidad de Sevilla, Spain) | Stochastic resonance with weak monochromatic driving: gains above unity
induced by high-frequency signals | 5 pages, 2 figures | Europhysics Letters {\bf 77}, 50004 (2007) | 10.1209/0295-5075/77/50004 | null | cond-mat.stat-mech | null | We study the effects of a high-frequency (HF) signal on the response of a
noisy bistable system to a low-frequency subthreshold sinusoidal signal. We
show that, by conveniently choosing the ratio of the amplitude of the HF signal
to its frequency, stochastic resonance gains greater than unity can be measured
at the low-frequency value. Thus, the addition of the HF signal can entail an
improvement in the detection of weak monochromatic signals. The results are
explained in terms of an effective model and illustrated by means of numerical
simulations.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:52:38 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Casado-Pascual",
"Jesús",
""
],
[
"Cubero",
"David",
""
],
[
"Baltanás",
"José Pablo",
""
]
] |
0705.0583 | Alexander Melnikov Dr. | Alexander V. Melnikov (1), Ivan I. Shevchenko (1) ((1) Pulkovo
Observatory of the Russian Academy of Sciences) | On reverberation and cross-correlation estimates of the size of the
broad-line region in active galactic nuclei | 26 pages, including 11 figures | null | 10.1111/j.1365-2966.2008.13609.x | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It is known that the dependence of the emission-line luminosity of a typical
cloud in the active galactic nuclei broad-line regions (BLRs) upon the incident
flux of ionizing continuum can be nonlinear. We study how this nonlinearity can
be taken into account in estimating the size of the BLR by means of the
"reverberation" methods. We show that the BLR size estimates obtained by
cross-correlation of emission-line and continuum light curves can be much (up
to an order of magnitude) less than the values obtained by reverberation
modelling. This is demonstrated by means of numerical cross-correlation and
reverberation experiments with model continuum flares and emission-line
transfer functions and by means of practical reverberation modelling of the
observed optical spectral variability of NGC 4151. The time behaviour of NGC
4151 in the H_alpha and H_beta lines is modelled on the basis of the
observational data by Kaspi et al. (1996, ApJ, 470, 336) and the theoretical
BLR model by Shevchenko (1984, Sov. Astron. Lett., 10, 377; 1985, Sov. Astron.
Lett., 11, 35). The values of the BLR parameters are estimated that allow to
judge on the size and physical characteristics of the BLR. The small size of
the BLR, as determined by the cross-correlation method from the data of Kaspi
et al. (1996, ApJ, 470, 336), is shown to be an artifact of this method. So,
the hypothesis that the BLR size varies in time is not necessitated by the
observational data.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 09:58:37 GMT"
},
{
"version": "v2",
"created": "Fri, 25 Jul 2008 09:58:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Melnikov",
"Alexander V.",
""
],
[
"Shevchenko",
"Ivan I.",
""
]
] |
0705.0584 | Giovanni Panti | Giovanni Panti | Multidimensional continued fractions and a Minkowski function | 17 pages, 3 figures. Revised version according to the referee's
suggestions. Proof of Lemma 2.3 more detailed, other minor modifications. To
appear in Monatshefte fur Mathematik | null | null | null | math.NT math.DS | null | The Minkowski Question Mark function can be characterized as the unique
homeomorphism of the real unit interval that conjugates the Farey map with the
tent map. We construct an n-dimensional analogue of the Minkowski function as
the only homeomorphism of an n-simplex that conjugates the piecewise-fractional
map associated to the Monkemeyer continued fraction algorithm with an
appropriate tent map.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:22:58 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Oct 2007 15:28:56 GMT"
}
] | 2007-10-02T00:00:00 | [
[
"Panti",
"Giovanni",
""
]
] |
0705.0585 | Jose Antonio Galvez | Jose M. Espinar, Jose A. Galvez, Harold Rosenberg | Complete surfaces with positive extrinsic curvature in product spaces | 28 pages | null | null | null | math.DG | null | We prove that every complete connected immersed surface with positive
extrinsic curvature $K$ in $H^2\times R$ must be properly embedded,
homeomorphic to a sphere or a plane and, in the latter case, study the behavior
of the end. Then, we focus our attention on surfaces with positive constant
extrinsic curvature ($K-$surfaces). We establish that the only complete
$K-$surfaces in $S^2\times R$ and $H^2\times R$ are rotational spheres. Here
are the key steps to achieve this. First height estimates for compact
$K-$surfaces in a general ambient space $M^2\times R$ with boundary in a slice
are obtained. Then distance estimates for compact $K-$surfaces (and
H-$surfaces) in $H^2\times R$ with boundary on a vertical plane are obtained.
Finally we construct a quadratic form with isolated zeroes of negative index.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:25:19 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 10:37:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Espinar",
"Jose M.",
""
],
[
"Galvez",
"Jose A.",
""
],
[
"Rosenberg",
"Harold",
""
]
] |
0705.0586 | Subir Ghosh | Subir Ghosh (Indian Statistical Institute) | Reply to Comment by J.A.Garcia, arXiv:0705.0143 (to appear in PRD) | null | null | null | null | hep-th | null | We observe that there is no clash between the works \cite{gar} and \cite{g1}.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:25:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ghosh",
"Subir",
"",
"Indian Statistical Institute"
]
] |
0705.0587 | Warren Dicks | Llu\'is Bacardit and Warren Dicks | Actions of the braid group, and new algebraic proofs of results of
Dehornoy and Larue | 51`pages, 13 figures | Groups Complexity Cryptology 1 (2009) 77-129. | 10.1515/GCC.2009.77 | null | math.GR | null | This article surveys many standard results about the braid group with
emphasis on simplifying the usual algebraic proofs.
We use van der Waerden's trick to illuminate the Artin-Magnus proof of the
classic presentation of the algebraic mapping-class group of a punctured disc.
We give a simple, new proof of the Dehornoy-Larue braid-group trichotomy,
and, hence, recover the Dehornoy right-ordering of the braid group.
We then turn to the Birman-Hilden theorem concerning braid-group actions on
free products of cyclic groups, and the consequences derived by Perron-Vannier,
and the connections with the Wada representations. We recall the very simple
Crisp-Paris proof of the Birman-Hilden theorem that uses the Larue-Shpilrain
technique. Studying ends of free groups permits a deeper understanding of the
braid group; this gives us a generalization of the Birman-Hilden theorem.
Studying Jordan curves in the punctured disc permits a still deeper
understanding of the braid group; this gave Larue, in his PhD thesis,
correspondingly deeper results, and, in an appendix, we recall the essence of
Larue's thesis, giving simpler combinatorial proofs.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:28:07 GMT"
}
] | 2016-08-14T00:00:00 | [
[
"Bacardit",
"Lluís",
""
],
[
"Dicks",
"Warren",
""
]
] |
0705.0588 | Edgar Graaf de | Edgar H. de Graaf, Joost N. Kok, Walter A. Kosters | Clustering Co-occurrence of Maximal Frequent Patterns in Streams | null | null | null | null | cs.AI cs.DS | null | One way of getting a better view of data is using frequent patterns. In this
paper frequent patterns are subsets that occur a minimal number of times in a
stream of itemsets. However, the discovery of frequent patterns in streams has
always been problematic. Because streams are potentially endless it is in
principle impossible to say if a pattern is often occurring or not. Furthermore
the number of patterns can be huge and a good overview of the structure of the
stream is lost quickly. The proposed approach will use clustering to facilitate
the analysis of the structure of the stream.
A clustering on the co-occurrence of patterns will give the user an improved
view on the structure of the stream. Some patterns might occur so much together
that they should form a combined pattern. In this way the patterns in the
clustering will be the largest frequent patterns: maximal frequent patterns.
Our approach to decide if patterns occur often together will be based on a
method of clustering when only the distance between pairs is known. The number
of maximal frequent patterns is much smaller and combined with clustering
methods these patterns provide a good view on the structure of the stream.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:36:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"de Graaf",
"Edgar H.",
""
],
[
"Kok",
"Joost N.",
""
],
[
"Kosters",
"Walter A.",
""
]
] |
0705.0589 | Paolo Piccione | Miguel Angel Javaloyes, Levi Lopes de Lima, Paolo Piccione | Iteration of closed geodesics in stationary Lorentzian manifolds | LaTeX2e, amsart, 22 pages. Acknowledgements of financial support
added | null | null | null | math.DG | null | Following the lines of a celebrated result by R. Bott (Comm. Pure Appl. Math.
9, 1956) we study the Morse index of the iterated of a closed geodesic in
stationary Lorentzian manifolds, or, more generally, of a closed Lorentzian
geodesic that admits a timelike periodic Jacobi field. Given one such closed
geodesic $\gamma$, we prove the existence of a locally constant integer valued
map $\Lambda_\gamma$ on the unit circle with the property that the Morse index
of the iterated $\gamma^N$ is equal, up to a correction term
$\epsilon_\gamma\in\{0,1\}$, to the sum of the values of $\Lambda_\gamma$ at
the $N$-th roots of unity. The discontinuities of $\Lambda_\gamma$ occur at a
finite number of points of the unit circle, that are special eigenvalues of the
linearized Poincar\'e map of $\gamma$. We discuss some applications of the
theory.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:33:44 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Jun 2007 22:42:33 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Javaloyes",
"Miguel Angel",
""
],
[
"de Lima",
"Levi Lopes",
""
],
[
"Piccione",
"Paolo",
""
]
] |
0705.0590 | Jun Zhang Dr. | Jun Zhang, Jun Ma, and Haimin Wang | Comparison of Magnetic Flux Distribution between a Coronal Hole and a
Quiet Region | null | Astrophys.J.649:464-469,2006 | 10.1086/506471 | null | astro-ph | null | Employing Big Bear Solar Observatory (BBSO) deep magnetograms and H${\alpha}$
images in a quiet region and a coronal hole, observed on September 14 and 16,
2004, respectively, we have explored the magnetic flux emergence, disappearance
and distribution in the two regions. The following results are obtained: (1)
The evolution of magnetic flux in the quiet region is much faster than that in
the coronal hole, as the flux appeared in the form of ephemeral regions in the
quiet region is 4.3 times as large as that in the coronal hole, and the flux
disappeared in the form of flux cancellation, 2.9 times as fast as in the
coronal hole. (2) More magnetic elements with opposite polarities in the quiet
region are connected by arch filaments, estimating from magnetograms and
H${\alpha}$ images. (3) We measured the magnetic flux of about 1000 magnetic
elements in each observing region. The flux distribution of network and
intranetwork (IN) elements is similar in both polarities in the quiet region.
For network fields in the coronal hole, the number of negative elements is much
more than that of positive elements. However for the IN fields, the number of
positive elements is much more than that of negative elements. (4) In the
coronal hole, the fraction of negative flux change obviously with different
threshold flux density. 73% of the magnetic fields with flux density larger
than 2 Gauss is negative polarity, and 95% of the magnetic fields is negative,
if we only measure the fields with their flux density larger than 20 Gauss. Our
results display that in a coronal hole, stronger fields is occupied by one
predominant polarity; however the majority of weaker fields, occupied by the
other polarity.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 12:34:01 GMT"
}
] | 2010-11-11T00:00:00 | [
[
"Zhang",
"Jun",
""
],
[
"Ma",
"Jun",
""
],
[
"Wang",
"Haimin",
""
]
] |
0705.0591 | Franc Forstneric | Franc Forstneric | The Oka principle for sections of stratified fiber bundles | Dedicated to Joseph J. Kohn on the occasion of his 75th birthday; to
appear in a special issue of Pure and Applied Math. Quarterly | Pure Appl. Math. Q., 6 (2010), no. 3, Special Issue: In honor of
Joseph J. Kohn. Part 1, 843-874 | null | null | math.CV | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A complex manifold Y satisfies the Convex Approximation Property (CAP) if
every holomorphic map from a neighborhood of a compact convex set K in a
complex Euclidean space C^n to Y can be approximated, uniformly on K, by entire
maps from C^n to Y. If X is a reduced Stein space and Z is a stratified
holomorphic fiber bundle over X all of whose fibers satisfy CAP, then sections
of Z over X enjoy the Oka property with (jet) interpolation and approximation.
Previously this has been proved by the author in the case when X is a Stein
manifold without singularities (Ann. Math., 163 (2006), 689-707,
math.CV/0402278; Ann. Inst. Fourier, 55 (2005), 733-751, math.CV/0411048). We
also give existence results for holomorphic sections under certain connectivity
hypothesis on the fibers. In the final part of the paper we obtain the Oka
property for sections of submersions with stratified sprays over Stein spaces.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:36:18 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 09:04:33 GMT"
},
{
"version": "v3",
"created": "Mon, 5 Nov 2007 20:01:39 GMT"
},
{
"version": "v4",
"created": "Mon, 21 Jul 2008 20:11:38 GMT"
},
{
"version": "v5",
"created": "Sun, 22 Mar 2009 19:41:23 GMT"
}
] | 2011-09-02T00:00:00 | [
[
"Forstneric",
"Franc",
""
]
] |
0705.0592 | Dipankar Bhattacharya | Dipankar Bhattacharya and Vikram Soni | A Natural Explanation for Magnetars | 5 pages, 1 figure | null | null | null | astro-ph | null | We explore the possibility that a magnetar may owe its strong magnetic field
to a magnetized core which, as indicated by certain equations of state, may
form due to phase transitions at high density mediated by strong interaction
within a sufficiently massive neutron star. We argue that the field derived
from such a core could explain several inferred evolutionary behaviors of
magnetars.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:39:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bhattacharya",
"Dipankar",
""
],
[
"Soni",
"Vikram",
""
]
] |
0705.0593 | Edgar Graaf de | Edgar H. de Graaf, Joost N. Kok, Walter A. Kosters | Clustering with Lattices in the Analysis of Graph Patterns | null | null | null | null | cs.AI cs.DS | null | Mining frequent subgraphs is an area of research where we have a given set of
graphs (each graph can be seen as a transaction), and we search for (connected)
subgraphs contained in many of these graphs. In this work we will discuss
techniques used in our framework Lattice2SAR for mining and analysing frequent
subgraph data and their corresponding lattice information. Lattice information
is provided by the graph mining algorithm gSpan; it contains all
supergraph-subgraph relations of the frequent subgraph patterns -- and their
supports.
Lattice2SAR is in particular used in the analysis of frequent graph patterns
where the graphs are molecules and the frequent subgraphs are fragments. In the
analysis of fragments one is interested in the molecules where patterns occur.
This data can be very extensive and in this paper we focus on a technique of
making it better available by using the lattice information in our clustering.
Now we can reduce the number of times the highly compressed occurrence data
needs to be accessed by the user. The user does not have to browse all the
occurrence data in search of patterns occurring in the same molecules. Instead
one can directly see which frequent subgraphs are of interest.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 10:52:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"de Graaf",
"Edgar H.",
""
],
[
"Kok",
"Joost N.",
""
],
[
"Kosters",
"Walter A.",
""
]
] |
0705.0594 | V. N. Zavaritsky | V.N. Zavaritsky | Reply to comment on "Essence of intrinsic tunnelling: Distinguishing
intrinsic features from artefacts | accepted for publication in PRB on 16 February 2007 | null | 10.1103/PhysRevB.75.146502 | null | cond-mat.supr-con | null | The recent PRB, henceforth referred as Ref.[1], experimentally resolves the
intrinsic shape of the c-axis current-voltage characteristics (IVC) of HTSC and
demonstrates that at sufficiently high heat loads the heating-induced IVC
nonlinearities exceed the intrinsic ones so radically that the latter might be
safely ignored.
The author of the comment fails to take account of the experimental findings
by Ref.[1] and seeks to cast doubt on all its conclusions through reference to
a brush-like IVC, which is claimed to be free of heating. I will show that this
claim lacks substantiation; indeed it can be stated with certainty that the IVC
is not free from heating. I will further show that the data selected for this
comment make it possible to explore for the first time the effect of
temperature on a range of loads where the genuine response is not hidden by
heating and to demonstrate for the first time that $R(T)$ of the same sample is
responsible for a rich variety of IVC behaviours taken above and below $T_c$ at
bath temperatures spanned over 180K. Thus these data in fact provide strong
novel evidence in favour of the major conclusions by Ref.[1], in particular the
extrinsic cause of the key findings by intrinsic tunnelling spectroscopy.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 11:03:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zavaritsky",
"V. N.",
""
]
] |
0705.0595 | Andrew Meulenberg Jr. | K. P. Sinha and A. Meulenberg | Lochon Catalyzed D-D Fusion in Deuterated Palladium in the Solid State | 3 pages: see also arXiv:cond-mat/0603213 (Current Science, Vol. 91,
No. 7, pp. 907-912, 10/10/06) Accepted for publication: National Academy of
Science (India) Letters | National Academy of Science (India) Letters, Vol.30, No. 7&8, 2007 | null | null | physics.gen-ph | null | Lochons (local charged bosons or local electron pairs) can form on D+ to give
D- (bosonic ions) in Palladium Deuteride in the solid state. Such entities will
occur at special sites or in linear channel owing to strong electron-phonon
interaction or due to potential inversion on metallic electrodes. These lochons
can catalyze D- - D+ fusion as a consequence of internal conversion leading to
the formation of He-4 plus production of energy (Q=23.8 MeV) which is carried
by the alpha particle and the ejected electron-pair. The reaction rate for this
fusion process is calculated.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 11:02:23 GMT"
}
] | 2011-06-15T00:00:00 | [
[
"Sinha",
"K. P.",
""
],
[
"Meulenberg",
"A.",
""
]
] |
0705.0596 | Gunter Sch\"utz | A. Brzank and G.M. Sch\"utz | Phase transition in the two-component symmetric exclusion process with
open boundaries | 26 pages, 6 figures | null | null | null | cond-mat.stat-mech | null | We consider single-file diffusion in an open system with two species $A,B$ of
particles. At the boundaries we assume different reservoir densities which
drive the system into a non-equilibrium steady state. As a model we use an
one-dimensional two-component simple symmetric exclusion process with two
different hopping rates $D_A,D_B$ and open boundaries. For investigating the
dynamics in the hydrodynamic limit we derive a system of coupled non-linear
diffusion equations for the coarse-grained particle densities. The relaxation
of the initial density profile is analyzed by numerical integration. Exact
analytical expressions are obtained for the self-diffusion coefficients, which
turns out to be length-dependent, and for the stationary solution. In the
steady state we find a discontinuous boundary-induced phase transition as the
total exterior density gradient between the system boundaries is varied. At one
boundary a boundary layer develops inside which the current flows against the
local density gradient. Generically the width of the boundary layer and the
bulk density profiles do not depend on the two hopping rates. At the phase
transition line, however, the individual density profiles depend strongly on
the ratio $D_A/D_B$. Dynamic Monte Carlo simulation confirm our theoretical
predictions.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 11:35:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brzank",
"A.",
""
],
[
"Schütz",
"G. M.",
""
]
] |
0705.0597 | Emilio Elizalde | Jaume Haro and Emilio Elizalde | Physically Sound Hamiltonian Formulation of the Dynamical Casimir Effect | 14 pages, no figures | Phys.Rev.D76:065001,2007 | 10.1103/PhysRevD.76.065001 | null | hep-th | null | Recently [J. Haro and E. Elizalde, Phys. Rev. Lett. {\bf 97}, 130401 (2006)],
a Hamiltonian formulation has been introduced in order to address some
longstanding severe problems associated with the physical description of the
dynamical Casimir effect at all times while the mirrors are moving. Here we
present the complete calculation providing precise details, in particular, of
the regularization procedure, which is decisive for the correct derivation of
physically meaningful quantities. A basic difference when comparing with the
results previously obtained by other authors is the fact that the motion force
derived in our approach contains a reactive term --proportional to the mirrors'
acceleration. This is of the essence in order to obtain particles with a
positive energy all the time during the oscillation of the mirrors --while
always satisfying the energy conservation law. A careful analysis of the
interrelations among the different results previously obtained in the
literature is then carried out. For simplicity, the specific case of a neutral
scalar field in one dimension, with one or two partially transmitting mirrors
(a fundamental proviso for the regularization issue) is considered in more
detail, but our general method is shown to be generalizable, without essential
problems (Sect. 2 of this paper), to fields of any kind in two and higher
dimensions.
| [
{
"version": "v1",
"created": "Fri, 4 May 2007 11:46:29 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Haro",
"Jaume",
""
],
[
"Elizalde",
"Emilio",
""
]
] |
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