title:
The transition of equation of state of effective dark energy in the DGP
  model with bulk contents

abstract:
  We investigate the effect of the bulk contents in the DGP braneworld on the
evolution of the universe. We find that although the pure DGP model cannot
accommodate the transition of the effective equation of state of dark energy,
once the bulk matter T^5_5 is considered, the modified model can realize the
w_{eff} crossing -1. However this transition of the equation of state cannot be
realized by just considering bulk-brane energy exchange or the GB effect while
the bulk matter contribution is not included. T^5_5 plays the major role in the
modified DGP model to have the w crossing -1 behavior. We show that our model
can describe the super-acceleration of our universe with the equation of state
of the effective dark energy and the Hubble parameter in agreement with
observations.


title:
A Simple Model for Pulse Profiles from Precessing Pulsars, with Special
  Application to Relativistic Binary PSR B1913+16

abstract:
  We study the observable pulse profiles that can be generated from precessing
pulsars. A novel coordinate system is defined to aid visualization of the
observing geometry. Using this system we explore the different families of
profiles that can be generated by simple, circularly symmetric beam shapes. An
attempt is then made to fit our model to the observations of relativistic
binary PSR B1913+16. It is found that while qualitatively similar pulse
profiles can be produced, this minimal model is insufficient for an accurate
match to the observational data. Consequently, we confirm that the emission
beam of PSR B1913+16 must deviate from circular symmetry, as first reported by
Weisberg and Taylor. However, the approximate fits obtained suggest that it may
be sufficient to consider only minimal deviations from a circular beam in order
to explain the data. We also comment on the applicability of our analysis
technique to other precessing pulsars, both binary and isolated.


title: Tunneling mechanism of light transmission through metallic films

abstract:
  A mechanism of light transmission through metallic films is proposed,
assisted by tunnelling between resonating buried dielectric inclusions. This is
illustrated by arrays of Si spheres embedded in Ag. Strong transmission peaks
are observed near the Mie resonances of the spheres. The interaction among
various planes of spheres and interference effects between these resonances and
the surface plasmons of Ag lead to mixing and splitting of the resonances.
Transmission is proved to be limited only by absorption. For small spheres, the
effective dielectric constant can be tuned to values close to unity and a
method is proposed to turn the resulting materials invisible.


title: Fixed-axis polarization states: covariance and comparisons

abstract:
  Addressing the recent criticisms of Kvinikhidze and Miller, we prove that the
spectator wave functions and currents based on ``fixed-axis'' polarization
states (previously introduced by us) are Lorentz covariant, and find an
explicit connection between them and conventional direction-dependent
polarization states. The discussion shows explicitly how it is possible to
construct pure $S$-wave models of the nucleon.


title:
Formal derivation of an exact series expansion for the Principal Field
  Emission Elliptic Function v

abstract:
  An exact series expansion is now known for the Principal Field Emission
Elliptic Function v, in terms of a complementary elliptic variable l' equal to
y*y, where y is the Nordheim parameter. This expansion was originally found by
using the algebraic manipulation package MAPLE. This paper presents a formal
mathematical derivation. It has been discovered that v(l') is a particular
solution of the ordinary differential equation (ODE) l'(1-l')d^2v/dl'^2=nv,
when the index n = 3/16. This ODE appears to be new in mathematical physics and
elliptic-function theory. The paper first uses an 1876 result from Cayley to
establish the boundary condition that dv/dl' satisfies as l' tends to zero. It
then uses the method of Frobenius to obtain two linearly independent series
solutions for the ODE, and hence derives the series expansion for v(l'). It is
shown that terms in ln{l'} are required in a mathematically correct solution,
but fractional powers of l' are not. The form of the ODE also implies that it
is mathematically impossible for simple Taylor expansion methods to generate
good approximation formulae valid over the whole range 0 =< l' =< 1; this
conclusion may also apply to barriers of other shapes. It is hoped that this
derivation might serve as a paradigm for the treatment of other tunnelling
barrier models for cold field electron emission, if in any particular case an
ODE can be found for which the tunnelling-exponent correction function is a
particular solution.


title: Spin Pumping of Current in Non-Uniform Conducting Magnets

abstract:
  Using irreversible thermodynamics we show that current-induced spin transfer
torque within a magnetic domain implies spin pumping of current within that
domain. This has experimental implications for samples both with conducting
leads and that are electrically isolated. These results are obtained by
deriving the dynamical equations for two models of non-uniform conducting
magnets: (1) a generic conducting magnet, with net conduction electron density
n and net magnetization $\vec{M}$; and (2) a two-band magnet, with up and down
spins each providing conduction and magnetism. For both models, in regions
where the equilibrium magnetization is non-uniform, voltage gradients can drive
adiabatic and non-adiabatic bulk spin torques. Onsager relations then ensure
that magnetic torques likewise drive adiabatic and non-adiabatic currents --
what we call bulk spin pumping. For a given amount of adiabatic and
non-adiabatic spin torque, the two models yield similar but distinct results
for the bulk spin pumping, thus distinguishing the two models. As in the recent
spin-Berry phase study by Barnes and Maekawa, we find that within a domain wall
the ratio of the effective emf to the magnetic field is approximately given by
$P(2\mu_{B}/e)$, where P is the spin polarization. The adiabatic spin torque
and spin pumping terms are shown to be dissipative in nature.


title: Fine-tune your smile: Correction to Hagan et al

abstract:
  In this small note we use results derived in Berestycki et al. to correct the
celebrated formulae of Hagan et al. We derive explicitly the correct zero order
term in the expansion of the implied volatility in time to maturity. The new
term is consistent as $\beta\to 1$. Furthermore, numerical simulations show
that it reduces or eliminates known pathologies of the earlier formula.


title: Plasmon tunability in metallodielectric metamaterials

abstract:
  The dielectric properties of metamaterials consisting of periodically
arranged metallic nanoparticles of spherical shape are calculated by rigorously
solving Maxwell's equations. Effective dielectric functions are obtained by
comparing the reflectivity of planar surfaces limiting these materials with
Fresnel's formulas for equivalent homogeneous media, showing mixing and
splitting of individual-particle modes due to inter-particle interaction.
Detailed results for simple cubic and fcc crystals of aluminum spheres in
vacuum, silver spheres in vacuum, and silver spheres in a silicon matrix are
presented. The filling fraction of the metal f is shown to determine the
position of the plasmon modes of these metamaterials. Significant deviations
are observed with respect to Maxwell-Garnett effective medium theory for large
f, and multiple plasmons are predicted to exist in contrast to Maxwell-Garnett
theory.


title:
Particle Acceleration and Magnetic Dissipation in Relativistic Current
  Sheet of Pair Plasmas

abstract:
  We study linear and nonlinear development of relativistic and
ultrarelativistic current sheets of pair plasmas with antiparallel magnetic
fields. Two types of two-dimensional problems are investigated by
particle-in-cell simulations. First, we present the development of relativistic
magnetic reconnection, whose outflow speed is an order of the light speed c. It
is demonstrated that particles are strongly accelerated in and around the
reconnection region, and that most of magnetic energy is converted into
"nonthermal" part of plasma kinetic energy. Second, we present another
two-dimensional problem of a current sheet in a cross-field plane. In this
case, the relativistic drift kink instability (RDKI) occurs. Particle
acceleration also takes place, but the RDKI fast dissipates the magnetic energy
into plasma heat. We discuss the mechanism of particle acceleration and the
theory of the RDKI in detail. It is important that properties of these two
processes are similar in the relativistic regime of T > mc^2, as long as we
consider the kinetics. Comparison of the two processes indicates that magnetic
dissipation by the RDKI is more favorable process in the relativistic current
sheet. Therefore the striped pulsar wind scenario should be reconsidered by the
RDKI.


title: Fundamental Strings, Holography, and Nonlinear Superconformal Algebras

abstract:
  We discuss aspects of holography in the AdS_3 \times S^p near string geometry
of a collection of straight fundamental heterotic strings. We use anomalies and
symmetries to determine general features of the dual CFT. The symmetries
suggest the appearance of nonlinear superconformal algebras, and we show how
these arise in the framework of holographic renormalization methods. The
nonlinear algebras imply intricate formulas for the central charge, and we show
that in the bulk these correspond to an infinite series of quantum gravity
corrections. We also makes some comments on the worldsheet sigma-model for
strings on AdS_3\times S^2, which is the holographic dual geometry of parallel
heterotic strings in five dimensions.


title:
On the finiteness of the noncommutative supersymmetric
  Maxwell-Chern-Simons theory

abstract:
  Within the superfield approach, we prove the absence of UV/IR mixing in the
three-dimensional noncommutative supersymmetric Maxwell-Chern-Simons theory at
any loop order and demonstrate its finiteness in one, three and higher loop
orders.


title:
How Magnetic Field Enters Heat Current: Application to Fluctuation
  Nernst Effect

abstract:
  A problem of the definition of the heat transported in thermomagnetic
phenomena has been well realized in the late sixties, but not solved up to
date. Ignoring this problem, numerous recent theories grossly overestimate the
thermomagnetic coefficients in strongly interacting systems. Here we develop a
gauge-invariant microscopic approach, which shows that the heat transfer should
include the energy of the interaction between electrons and a magnetic field.
We also demonstrate that the surface currents induced by the magnetic field
transfer the charge in the Nernst effect, but do not transfer the heat in the
Ettingshausen effect. Only with these two modifications of the theory, the
physically measurable thermomagnetic coefficients satisfy the Onsager relation.
We critically revised the Gaussian fluctuation model above the superconducting
transition and show that the gauge invariance uniquely relates thermomagnetic
phenomena in the Fermi liquid with the particle-hole asymmetry.


title: Cluster Formation in Contracting Molecular Clouds

abstract:
  We explore, through a simplified, semi-analytic model, the formation of dense
clusters containing massive stars. The parent cloud spawning the cluster is
represented as an isothermal sphere. This sphere is in near force balance
between self-gravity and turbulent pressure. Self-gravity, mediated by
turbulent dissipation, drives slow contraction of the cloud, eventually leading
to a sharp central spike in density and the onset of dynamical instability. We
suggest that, in a real cloud, this transition marks the late and rapid
production of massive stars.
  We also offer an empirical prescription, akin to the Schmidt law, for
low-mass star formation in our contracting cloud. Applying this prescription to
the Orion Nebula Cluster, we are able to reproduce the accelerating star
formation previously inferred from the distribution of member stars in the HR
diagram. The cloud turns about 10 percent of its mass into low-mass stars
before becoming dynamically unstable. Over a cloud free-fall time, this figure
drops to 1 percent, consistent with the overall star formation efficiency of
molecular clouds in the Galaxy.


title:
Langevin Dynamics of the vortex matter two-stage melting transition in
  Bi_2Sr_2CaCu_2O$_{8+\delta}$ in the presence of straight and of tilted
  columnar defects

abstract:
  In this paper we use London Langevin molecular dynamics simulations to
investigate the vortex matter melting transition in the highly anisotropic
high-temperature superconductor material Bi_2Sr_2CaCu_2O$_{8+\delta}$ in the
presence of low concentration of columnar defects (CDs). We reproduce with
further details our previous results obtained by using Multilevel Monte Carlo
simulations that showed that the melting of the nanocrystalline vortex matter
occurs in two stages: a first stage melting into nanoliquid vortex matter and a
second stage delocalization transition into a homogeneous liquid. Furthermore,
we report on new dynamical measurements in the presence of a current that
identifies clearly the irreversibility line and the second stage delocalization
transition. In addition to CDs aligned along the c-axis we also simulate the
case of tilted CDs which are aligned at an angle with respect to the applied
magnetic field. Results for CDs tilted by $45^{\circ}$ with respect to c-axis
show that the locations of the melting and delocalization transitions are not
affected by the tilt when the ratio of flux lines to CDs remains constant. On
the other hand we argue that some dynamical properties and in particular the
position of the irreversibility line should be affected.


title:
Electromagnetic forces and torques in nanoparticles irradiated by a
  plane wave

abstract:
  Optical tweezers and optical lattices are making it possible to control small
particles by means of electromagnetic forces and torques. In this context, a
method is presented in this work to calculate electromagnetic forces and
torques for arbitrarily-shaped objects in the presence of other objects
illuminated by a plane wave. The method is based upon an expansion of the
electromagnetic field in terms of multipoles around each object, which are in
turn used to derive forces and torques analytically. The calculation of
multipole coefficients are obtained numerically by means of the boundary
element method. Results are presented for both spherical and non-spherical
objects.


title:
On-Chip Matching Networks for Radio-Frequency
  Single-Electron-Transistors

abstract:
  In this letter, we describe operation of a radio-frequency superconducting
single electron transistor (RF-SSET) with an on-chip superconducting LC
matching network consisting of a spiral inductor L and its capacitance to
ground. The superconducting network has a lower parasitic capacitance and gives
a better matching for the RF-SSET than does a commercial chip inductor.
Moreover, the superconducting network has negligibly low dissipation, leading
to sensitive response to changes in the RF-SSET impedance. The charge
sensitivity 2.4*10^-6 e/(Hz)^1/2 in the sub-gap region and energy sensitivity
of 1.9 hbar indicate that the RF-SSET is operating in the vicinity of the shot
noise limit.


title: An Isotropic Metric

abstract:
  An isotropic metric for a black hole and a better vacuum condition \nabla^2
V_G =0 are presented which yield distinct terms for the energy densities of
ordinary matter and gravitational fields in the Einstein tensor (G^44 =-g^2
(2\nabla^2 V_G +(\nabla V_G)^2)) This model resolves an inconsistency between
electromagnetism and gravity in the calculation of field energy. Resolution of
this inconsistency suggests a slight modification of the Einstein equation to
gG^\mu\nu = 8\pi G T^\mu\nu.


title: An SU(5)$\otimes$Z_{13} Grand Unification Model

abstract:
  We propose an SU(5) grand unified model with an invisible axion and the
unification of the three coupling constants which is in agreement with the
values, at $M_Z$, of $\alpha$, $\alpha_s$, and $\sin^2\theta_W$. A discrete,
anomalous, $Z_{13}$ symmetry implies that the Peccei-Quinn symmetry is an
automatic symmetry of the classical Lagrangian protecting, at the same time,
the invisible axion against possible semi-classical gravity effects. Although
the unification scale is of the order of the Peccei-Quinn scale the proton is
stabilized by the fact that in this model the standard model fields form the
SU(5) multiplets completed by new exotic fields and, also, because it is
protected by the $Z_{13}$ symmetry.


title: Search for a pentaquark decaying to Cascade- pi-

abstract:
  We present a search for a pentaquark decaying strongly to $\Xi^-\pi^-$ in
$\gamma N$ collisions at a center-of-mass energy up to 25 GeV/c^2. Finding no
evidence for such a state in the mass range of 1480 MeV/c^2 to 2400 MeV/c^2, we
set limits on the yield and on the cross section times branching ratio relative
to $\Xi^*(1530)^0$.


title: Resonance scattering in the X-ray emission line profiles of Zeta Puppis

abstract:
  We present XMM-Newton Reflection Grating Spectrometer observations of pairs
of X-ray emission line profiles from the O star Zeta Pup that originate from
the same He-like ion. The two profiles in each pair have different shapes and
cannot both be consistently fit by models assuming the same wind parameters. We
show that the differences in profile shape can be accounted for in a model
including the effects of resonance scattering, which affects the resonance line
in the pair but not the intercombination line. This implies that resonance
scattering is also important in single resonance lines, where its effect is
difficult to distinguish from a low effective continuum optical depth in the
wind. Thus, resonance scattering may help reconcile X-ray line profile shapes
with literature mass-loss rates.


title: Spin-exchange relaxation free magnetometry with Cs vapor

abstract:
  We describe a Cs atomic magnetometer operating in the spin-exchange
relaxation-free (SERF) regime. With a vapor cell temperature of
$103^\circ\rm{C}$ we achieve intrinsic magnetic resonance widths $\Delta B=17
{\rm \mu G}$ corresponding to an electron spin-relaxation rate of $300 {\rm
s^{-1}}$ when the spin-exchange rate is $\Gamma_{SE}=14000 {\rm s^{-1}}$. We
also observe an interesting narrowing effect due to diffusion. Signal-to-noise
measurements yield a sensitivity of about $400\thinspace{\rm pG/\sqrt{Hz}}$.
Based on photon shot noise, we project a sensitivity of $40 {\rm
pG/\sqrt{Hz}}$. A theoretical optimization of the magnetometer indicates
sensitivities on the order of $2 {\rm pG/\sqrt{Hz}}$ should be achievable in a
$1 {\rm cm^3}$ volume. Because Cs has a higher saturated vapor pressure than
other alkali metals, SERF magnetometers using Cs atoms are particularly
attractive in applications requiring lower temperatures.


title: Noise-induced energy excitation by a general environment

abstract:
  We analyze the effects that general environments, namely ohmic and non-ohmic,
at zero and high temperature induce over a quantum Brownian particle. We state
that the evolution of the system can be summarized in terms of two main
environmental induced physical phenomena: decoherence and energy activation. In
this article we show that the latter is a post-decoherence phenomenon. As the
energy is an observable, the excitation process is a direct indication of the
system-environment entanglement particularly useful at zero temperature.


title: Evolution of Gravitational Perturbations in Non-Commutative Inflation

abstract:
  We consider the non-commutative inflation model of [3] in which it is the
unconventional dispersion relation for regular radiation which drives the
accelerated expansion of space. In this model, we study the evolution of linear
cosmological perturbations through the transition between the phase of
accelerated expansion and the regular radiation-dominated phase of Standard
Cosmology, the transition which is analogous to the reheating period in scalar
field-driven models of inflation. If matter consists of only a single
non-commutative radiation fluid, then the curvature perturbations are constant
on super-Hubble scales. On the other hand, if we include additional matter
fields which oscillate during the transition period, e.g. scalar moduli fields,
then there can be parametric amplification of the amplitude of the curvature
perturbations. We demonstrate this explicitly by numerically solving the full
system of perturbation equations in the case where matter consists of both the
non-commutative radiation field and a light scalar field which undergoes
oscillations. Our model is an example where the parametric resonance of the
curvature fluctuations is driven by the oscillations not of the inflaton field,
but of the entropy mode


title: Prime numbers with Beatty sequences

abstract:
  A study of certain Hamiltonian systems has lead Y. Long to conjecture the
existence of infinitely many primes of the form $p=2[\alpha n]+1$, where
$1<\alpha<2$ is a fixed irrational number. An argument of P. Ribenboim coupled
with classical results about the distribution of fractional parts of irrational
multiples of primes in an arithmetic progression immediately imply that this
conjecture holds in a much more precise asymptotic form. Motivated by this
observation, we give an asymptotic formula for the number of primes $p=q[\alpha
n+\beta]+a$ with $n\le N$, where $\alpha,\beta$ are real numbers such that
$\alpha$ is positive and irrational of finite type (which is true for almost
all $\alpha$) and $a,q$ are integers with $0\le a<q\le N^\kappa$ and
$\gcd(a,q)=1$, where $\kappa>0$ depends only on $\alpha$. We also prove a
similar result for primes $p=[\alpha n+\beta]$ such that $p\equiv a\pmod q$.


title: Rotating Black Holes on Codimension-2 Branes

abstract:
  It has recently been demonstrated that certain types of non-tensional
stress-energy can live on tensional codimension-2 branes, including
gravitational shockwaves and small Schwarzschild black holes. In this note we
generalize the earlier Schwarzschild results, and construct the exact
gravitational fields of small rotating black holes on a codimension-2 brane. We
focus on the phenomenologically interesting case of a three-brane embedded in a
spacetime with two compactified extra dimensions. For a nonzero tension on the
brane, we verify that these solutions also show the ``lightning rod'' effect
found in the Schwarzschild solutions, the net effect of which is to rescale the
fundamental Planck mass. This allows for larger black hole parameters, such as
the event horizon, angular momentum, and lifetime than would be naively
expected for a tensionless brane. It is also found that a black hole with
angular momentum pointing purely along the brane directions has a smaller
horizon angular velocity than the corresponding tensionless case, while a hole
with bulk components of angular momentum has a larger angular velocity.


title: On the injectivity of the X-ray transform for Anosov thermostats

abstract:
  We consider Anosov thermostats on a closed surface and the X-ray transform on
functions which are up to degree two in the velocities. We show that the
subspace where the X-ray transform fails to be s-injective is finite
dimensional. Furthermore, if the surface is negatively curved and the
thermostat is pure Gaussian (i.e. no magnetic field is present), then the X-ray
transform is s-injective.


title:
Normal State Nernst Effect in Electron-doped Pr2-xCexCuO4:
  Superconducting Fluctuations and Two-band Transport

abstract:
  We report a systematic study of normal state Nernst effect in the
electron-doped cuprates Pr$_{2-x}$Ce$_x$CuO$_{4-\delta}$ over a wide range of
doping (0.05$\leq x \leq$0.21) and temperature. At low temperatures, we
observed a notable vortex Nernst signal above T$_c$ in the underdoped films,
but no such normal state vortex Nernst signal is found in the overdoped region.
The superconducting fluctuations in the underdoped region are most likely
incoherent phase fluctuations as found in hole-doped cuprates. At high
temperatures, a large normal state Nernst signal is found at dopings from
slightly underdoped to highly overdoped. Combined with normal state
thermoelectric power, Hall effect and magnetoresistance measurements, the large
Nernst effect is compatible with two-band model. For the highly overdoped
films, the large Nernst effect is anomalous and not explainable with a simple
hole-like Fermi surface seen in photoemission experiments.


title:
1/Nc Expansion in QCD: Double-Line Counting Rules and the Undeservingly
  Discarded U(1) Ghost

abstract:
  The 1/Nc expansion is one of the very few methods we have for generating a
systematic expansion of QCD at the energy scale relevant to hadron structure.
The present formulation of this theory relies on the double-line notation for
calculating the leading order of a diagram in the 1/Nc expansion, where the
local SU(Nc) gauge symmetry is substituted by a U(Nc) symmetry and the
associated U(1) ghost field is ignored. In the current work we demonstrate the
insufficiency of this formulation for describing certain non-planar diagrams.
We derive a more complete set of Feynman rules that include the U(1) ghost
field and provide a useful tool for calculating both color factors and 1/Nc
orders of all color-singlet diagrams.


title:
Evidence for a Population of High-Redshift Submillimeter Galaxies from
  Interferometric Imaging

abstract:
  We have used the Submillimeter Array to image a flux limited sample of seven
submillimeter galaxies, selected by the AzTEC camera on the JCMT at 1.1 mm, in
the COSMOS field at 890um with 2" resolution. All of the sources - two
radio-bright and five radio-dim - are detected as single point-sources at high
significance (> 6\sigma), with positions accurate to 0.2" that enable
counterpart identification at other wavelengths observed with similarly high
angular resolution. All seven have IRAC counterparts, but only two have secure
counterparts in deep HST/ACS imaging. As compared to the two radio-bright
sources in the sample, and those in previous studies, the five radio-dim
sources in the sample (1) have systematically higher submillimeter-to-radio
flux ratios, (2) have lower IRAC 3.6-8.0um fluxes, and (3) are not detected at
24um. These properties, combined with size constraints at 890um (\theta <
1.2"), suggest that the radio-dim submillimeter galaxies represent a population
of very dusty starbursts, with physical scales similar to local ultraluminous
infrared galaxies, and an average redshift higher than radio-bright sources.


title: Codeword Stabilized Quantum Codes

abstract:
  We present a unifying approach to quantum error correcting code design that
encompasses additive (stabilizer) codes, as well as all known examples of
nonadditive codes with good parameters. We use this framework to generate new
codes with superior parameters to any previously known. In particular, we find
((10,18,3)) and ((10,20,3)) codes. We also show how to construct encoding
circuits for all codes within our framework.


title:
The Detectability of Neon Fluorescence and Measurement of the Solar
  Photospheric Neon Abundance

abstract:
  Monte Carlo calculations of the Ne K$\alpha$ line fluoresced by coronal
x-rays and emitted near the temperature minimum region of the solar atmosphere
have been employed to investigate the use of this feature to measure directly
the solar photospheric Ne abundance. Though very weak, comparison with spectral
line databases indicates that at plasma temperatures typical of the quiet Sun
and cool active regions ($\leq 2\times 10^6$ K) the line is isolated and
unblended. A canonical solar chemical composition yields an equivalent width of
$\sim 6$ m\AA (0.3 eV) when observed at heliocentric angles $\sim 0$. For a 1
arcmin field of view, photon fluxes at Earth are of order 0.2 ph s$^{-1}$ for
the quiet Sun, rendering the Ne K$\alpha$ fluorescent line a quite feasible
means for determining the solar photospheric Ne content.


title:
Quaternionic Kahler Manifolds, Constrained Instantons and the Magic
  Square: I

abstract:
  The classification of homogeneous quaternionic manifolds has been done by
Alekseevskii, Wolf et al using transitive solvable group of isometries. These
manifolds are not generically symmetric, but there is a subset of quaternionic
manifolds that are symmetric and Einstein. A further subset of these manifolds
are the magic square manifolds. We show that all the symmetric quaternionic
manifolds including the magic square can be succinctly classified by
constrained instantons. These instantons are mostly semilocal, and their
constructions for the magic square can be done from the corresponding
Seiberg-Witten curves for certain N = 2 gauge theories that are in general not
asymptotically free. Using these, we give possible constructions, such as the
classical moduli space metrics, of constrained instantons with exceptional
global symmetries. We also discuss the possibility of realising the Kahler
manifolds in the magic square using other solitonic configurations in the
theory, and point out an interesting new sequence of these manifolds in the
magic square.


title: Neutron star magnetospheres: the binary pulsar, Crab and magnetars

abstract:
  A number of disparate observational and theoretical pieces of evidence
indicate that, contrary to the conventional wisdom, neutron stars' closed field
lines are populated by dense, hot plasma and may be responsible for producing
some radio and high energy emission. This conclusion is based on eclipse
modeling of the binary pulsar system PSR J0737-3039A/B (Lyutikov & Thompson
2005), a quantitative theory of Crab giant pulses (Lyutikov 2007) and a number
of theoretical works related to production of non-thermal spectra in magnetars
through resonant scattering. In magnetars, dense pair plasma is produced by
twisting magnetic field lines and associated electric fields required to lift
the particles from the surface. In long period pulsars, hot particles on closed
field lines can be efficiently trapped by magnetic mirroring, so that
relatively low supply rate, e.g. due to a drift from open field lines, may
result in high density. In short period pulsars, magnetic mirroring does not
work; large densities may still be expected at the magnetic equator near the
Y-point.


title: Entanglement Distribution in Pure-State Quantum Networks

abstract:
  We investigate entanglement distribution in pure-state quantum networks. We
consider the case when non-maximally entangled two-qubit pure states are shared
by neighboring nodes of the network. For a given pair of nodes, we investigate
how to generate the maximal entanglement between them by performing local
measurements, assisted by classical communication, on the other nodes. We find
optimal measurement protocols for both small and large 1D networks. Quite
surprisingly, we prove that Bell measurements are not always the optimal ones
to perform in such networks. We generalize then the results to simple small 2D
networks, finding again counter-intuitive optimal measurement strategies.
Finally, we consider large networks with hierarchical lattice geometries and 2D
networks. We prove that perfect entanglement can be established on large
distances with probability one in a finite number of steps, provided the
initial entanglement shared by neighboring nodes is large enough. We discuss
also various protocols of entanglement distribution in 2D networks employing
classical and quantum percolation strategies.


title: The Radio Evolution of SN 2001gd

abstract:
  We present the results of observations of the radio emission from Supernova
2001gd in NGC 5033 from 2002 February 8 through 2006 September 25. The data
were obtained using the Very Large Array at wavelengths of 1.3 cm (22.4 GHz), 2
cm (14.9 GHz), 3.6 cm (8.4 GHz), 6 cm (4.9 GHz), and 20 cm (1.5 GHz), with one
upper limit at 90 cm (0.3 GHz). In addition, one detection has been provided by
the Giant Metrewave Radio Telescope at 21 cm (1.4 GHz). SN 2001gd was
discovered in the optical well past maximum light, so that it was not possible
to obtain many of the early radio "turn-on" measurements which are important
for estimating the local circumstellar medium (CSM) properties. Only at 20 cm
were turn-on data available. However, our analysis and fitting of the radio
light curves, and the assumption that the Type IIb SN 2001gd resembles the much
better studied Type IIb SN 1993J, enables us to describe the radio evolution as
being very regular through day ~550 and consistent with a nonthermal-emitting
model with a thermal absorbing CSM. The presence of synchrotron-self absorption
(SSA) at early times is implied by the data, but determination of the exact
relationship between the SSA component from the emitting region and the
free-free absorption component from the CSM is not possible as there are
insufficient early measurements to distinguish between models. After day ~550,
the radio emission exhibits a dramatically steeper decline rate which, assuming
similarity to SN 1993J, can be described as an exponential decrease with an
e-folding time of 500 days. We interpret this abrupt change in the radio flux
density decline rate as implying a transition of the shock front into a more
tenuous region of circumstellar material. A similar change in radio evolution
has been seen earlier in other SNe such as SN 1988Z, SN 1980K, and SN 1993J.


title: Unusual oxygen isotope effects in cuprates -- importance of doping

abstract:
  A recent angle resolved photoelectron spectroscopy (ARPES) study by Douglas
et al. \cite {dessau-comment} on oxygen isotope exchanged
Bi_2Sr_2CaCu_2O$_{8+\delta}$ superconductors reported an absence of isotope
effect at optimal doping, questioning the previous work by us \cite
{gweon-nature}. Here, we report a new result that sheds light on this puzzling
discrepancy as well as the nature of the electron lattice interaction in the
cuprates: the anomalous isotope effect at optimal doping \cite {gweon-nature},
re-confirmed here, vanishes on a mere 2 % overdoping of holes. This result
implies a rapid change of the nature of the electron-lattice interaction near
optimal doping. We also find that the data by Douglas et al. \cite
{dessau-comment} are actually characteristic of significantly over-doped
samples, not of optimally doped samples as they claimed.


title: MTGEN : Mass scale measurements in pair-production at colliders

abstract:
  We introduce a new kinematic event variable MTGEN which can provide
information relating to the mass scales of particles pair-produced at hadronic
and leptonic colliders. The variable is of particular use in events with a
large number of particles in the final state when some of those particles are
massive and not detected, such as may arise in R-parity-conserving
supersymmetry.


title:
Study of Cabibbo Suppressed Decays of the Ds Charmed-Strange Meson
  involving a KS

abstract:
  We study the decay of Ds meson into final states involving a Ks and report
the discovery of Cabibbo suppressed decay modes Ds -> Kspi-pi+pi+ (179 +/- 36
events) and Ds -> Kspi+ (113 +/-26 events). The branching ratios for the new
modes are Gamma(Ds -> Kspi-pi+pi+)/Gamma(Ds -> KsK-pi+pi+) = 0.18 +/- 0.04 +/-
0.05 and Gamma(Ds -> Kspi+)/Gamma(Ds -> KsK+) = 0.104 +/- 0.024 +/- 0.013.


title: Discovery of a New Dusty B[e] Star in the Small Magellanic Cloud

abstract:
  We present new optical spectroscopic and archival Spitzer IRAC photometric
observations of a B-type star in the SMC cluster NGC 346, NGC 346:KWBBe 200. We
detect numerous Fe II, [O I], and [Fe II] lines, as well as strong P-Cygni
profile H I emission lines in its optical spectrum. The star's near-IR color
and optical to IR SED clearly indicate the presence of an infrared excess,
consistent with the presence of gas and warm, T ~800 K, circumstellar dust.
Based on a crude estimate of the star's luminosity and the observed
spectroscopic line profile morphologies, we find that the star is likely to be
a B-type supergiant. We suggest that NGC 346:KWBBe 200 is a newly discovered
B[e] supergiant star, and represents the fifth such object to be identified in
the SMC.


title:
Perturbation theory for anisotropic dielectric interfaces, and
  application to sub-pixel smoothing of discretized numerical methods

abstract:
  We derive a correct first-order perturbation theory in electromagnetism for
cases where an interface between two anisotropic dielectric materials is
slightly shifted. Most previous perturbative methods give incorrect results for
this case, even to lowest order, because of the complicated discontinuous
boundary conditions on the electric field at such an interface. Our final
expression is simply a surface integral, over the material interface, of the
continuous field components from the unperturbed structure. The derivation is
based on a "localized" coordinate-transformation technique, which avoids both
the problem of field discontinuities and the challenge of constructing an
explicit coordinate transformation by taking a limit in which a coordinate
perturbation is infinitesimally localized around the boundary. Not only is our
result potentially useful in evaluating boundary perturbations, e.g. from
fabrication imperfections, in highly anisotropic media such as many
metamaterials, but it also has a direct application in numerical
electromagnetism. In particular, we show how it leads to a sub-pixel smoothing
scheme to ameliorate staircasing effects in discretized simulations of
anisotropic media, in such a way as to greatly reduce the numerical errors
compared to other proposed smoothing schemes.


title: Generalized Kaehler Potentials from Supergravity

abstract:
  We consider supersymmetric N=2 solutions with non-vanishing NS three-form.
Building on worldsheet results, we reduce the problem to a single generalized
Monge-Ampere equation on the generalized Kaehler potential K recently
interpreted geometrically by Lindstrom, Rocek, Von Unge and Zabzine. One input
in the procedure is a holomorphic function w that can be thought of as the
effective superpotential for a D3 brane probe. The procedure is hence likely to
be useful for finding gravity duals to field theories with non-vanishing
abelian superpotential, such as Leigh-Strassler theories. We indeed show that a
purely NS precursor of the Lunin-Maldacena dual to the beta-deformed N=4
super-Yang-Mills falls in our class.


title: Double Beta Decay, Majorana Neutrinos, and Neutrino Mass

abstract:
  The theoretical and experimental issues relevant to neutrinoless double-beta
decay are reviewed. The impact that a direct observation of this exotic process
would have on elementary particle physics, nuclear physics, astrophysics and
cosmology is profound. Now that neutrinos are known to have mass and
experiments are becoming more sensitive, even the non-observation of
neutrinoless double-beta decay will be useful. If the process is actually
observed, we will immediately learn much about the neutrino. The status and
discovery potential of proposed experiments are reviewed in this context, with
significant emphasis on proposals favored by recent panel reviews. The
importance of and challenges in the calculation of nuclear matrix elements that
govern the decay are considered in detail. The increasing sensitivity of
experiments and improvements in nuclear theory make the future exciting for
this field at the interface of nuclear and particle physics.


title:
On deciding stability of multiclass queueing networks under buffer
  priority scheduling policies

abstract:
  One of the basic properties of a queueing network is stability. Roughly
speaking, it is the property that the total number of jobs in the network
remains bounded as a function of time. One of the key questions related to the
stability issue is how to determine the exact conditions under which a given
queueing network operating under a given scheduling policy remains stable.
While there was much initial progress in addressing this question, most of the
results obtained were partial at best and so the complete characterization of
stable queueing networks is still lacking. In this paper, we resolve this open
problem, albeit in a somewhat unexpected way. We show that characterizing
stable queueing networks is an algorithmically undecidable problem for the case
of nonpreemptive static buffer priority scheduling policies and deterministic
interarrival and service times. Thus, no constructive characterization of
stable queueing networks operating under this class of policies is possible.
The result is established for queueing networks with finite and infinite buffer
sizes and possibly zero service times, although we conjecture that it also
holds in the case of models with only infinite buffers and nonzero service
times. Our approach extends an earlier related work [Math. Oper. Res. 27 (2002)
272--293] and uses the so-called counter machine device as a reduction tool.


title: Neutrino flavor ratios as diagnostic of solar WIMP annihilation

abstract:
  We consider the neutrino (and antineutrino) flavors arriving at Earth for
neutrinos produced in the annihilation of weakly interacting massive particles
(WIMPs) in the Sun's core. Solar-matter effects on the flavor propagation of
the resulting $\agt$ GeV neutrinos are studied analytically within a
density-matrix formalism. Matter effects, including mass-state level-crossings,
influence the flavor fluxes considerably. The exposition herein is somewhat
pedagogical, in that it starts with adiabatic evolution of single flavors from
the Sun's center, with $\theta_{13}$ set to zero, and progresses to fully
realistic processing of the flavor ratios expected in WIMP decay, from the
Sun's core to the Earth. In the fully realistic calculation, non-adiabatic
level-crossing is included, as are possible nonzero values for $\theta_{13}$
and the CP-violating phase $\delta$. Due to resonance enhancement in matter,
nonzero values of $\theta_{13}$ even smaller than a degree can noticeably
affect flavor propagation. Both normal and inverted neutrino-mass hierarchies
are considered. Our main conclusion is that measuring flavor ratios (in
addition to energy spectra) of $\agt$ GeV solar neutrinos can provide
discrinination between WIMP models. In particular, we demonstrate the flavor
differences at Earth for neutrinos from the two main classes of WIMP final
states, namely $W^+ W^-$ and 95% $b \bar{b}$ + 5% $\tau^+\tau^-$. Conversely,
if WIMP properties were to be learned from production in future accelerators,
then the flavor ratios of $\agt$ GeV solar neutrinos might be useful for
inferring $\theta_{13}$ and the mass hierarchy.


title:
Kaehler-Ricci Flow, Morse Theory, and Vacuum Structure Deformation of
  N=1 Supersymmetry in Four Dimensions

abstract:
  We address some aspects of four dimensional chiral N=1 supersymmetric
theories on which the scalar manifold is described by K\"ahler geometry and can
further be viewed as K\"ahler-Ricci soliton generating a one-parameter family
of K\"ahler geometries. All couplings and solutions, namely the BPS domain
walls and their supersymmetric Lorentz invariant vacua turn out to be evolved
with respect to the flow parameter related to the soliton. Two models are
discussed, namely N=1 theory on K\"ahler-Einstein manifold and U(n) symmetric
K\"ahler-Ricci soliton with positive definite metric. In the first case we find
that the evolution of the soliton causes topological change and
correspondingly, modifies the Morse index of the nondegenerate vacua realized
in the parity transformation of the Hessian matrix of the scalar potential
after hitting singularity, which is natural in the global theory and for
nondegenerate Minkowskian vacua of the local theory. However, such situation is
not trivial in anti de Sitter (AdS) vacua. In an explicit model, we find that
this geometric (K\"ahler-Ricci) flow can also change the index of the vacuum
before and after singularity. Finally in the second case, since around the
origin the metric is diffeomorphic to $ {\mathrm{\lC P}}^{n -1}$, we have to
consider it in the asymptotic region. Our analysis shows that no index
modification of vacua is present in both global and local theories.


title: A Formulation of the Channel Capacity of Multiple-Access Channel

abstract:
  The necessary and sufficient condition of the channel capacity is rigorously
formulated for the N-user discrete memoryless multiple-access channel (MAC).
The essence of the formulation is to invoke an {\em elementary} MAC where sizes
of input alphabets are not greater than the size of output alphabet. The main
objective is to demonstrate that the channel capacity of an MAC is achieved by
an elementary MAC included in the original MAC. The proof is quite
straightforward by the very definition of the elementary MAC. Moreover it is
proved that the Kuhn-Tucker conditions of the elementary MAC are strictly
sufficient and obviously necessary for the channel capacity. The latter proof
requires some steps such that for the elementary MAC every solution of the
Kuhn-Tucker conditions reveals itself as local maximum on the domain of all
possible input probability distributions and then it achieves the channel
capacity. As a result, in respect of the channel capacity, the MAC in general
can be regarded as an aggregate of a finite number of elementary MAC's.


title:
Crossing the phantom divide in brane cosmology with curvature
  corrections and brane-bulk energy transfer

abstract:
  We consider the Randall-Sundrum brane-world model with bulk-brane energy
transfer where the Einstein-Hilbert action is modified by curvature correction
terms: a four-dimensional scalar curvature from induced gravity on the brane,
and a five-dimensional Gauss-Bonnet curvature term. It is remarkable that these
curvature terms will not change the dynamics of the brane universe at low
energy. Parameterizing the energy transfer and taking the dark radiation term
into account, we find that the phantom divide of the equation of state of
effective dark energy could be crossed, without the need of any new dark energy
components. Fitting the two most reliable and robust SNIa datasets, the 182
Gold dataset and the Supernova Legacy Survey (SNLS), our model indeed has a
small tendency of phantom divide crossing for the Gold dataset, but not for the
SNLS dataset. Furthermore, combining the recent detection of the SDSS baryon
acoustic oscillations peak (BAO) with lower matter density parameter prior, we
find that the SNLS dataset also mildly favors phantom divide crossing.


title: Ammonia Imaging of the Disks in the NGC 1333 IRAS 4A Protobinary System

abstract:
  The NGC 1333 IRAS 4A protobinary was observed in the ammonia (2, 2) and (3,
3) lines and in the 1.3 cm continuum with a high resolution (about 1.0 arcsec).
The ammonia maps show two compact sources, one for each protostar, and they are
probably protostellar accretion disks. The disk associated with IRAS 4A2 is
seen nearly edge-on and shows an indication of rotation. The A2 disk is
brighter in the ammonia lines but dimmer in the dust continuum than its sibling
disk, with the ammonia-to-dust flux ratios different by about an order of
magnitude. This difference suggests that the twin disks have surprisingly
dissimilar characters, one gas-rich and the other dusty. The A2 disk may be
unusually active or hot, as indicated by its association with water vapor
masers. The existence of two very dissimilar disks in a binary system suggests
that the formation process of multiple systems has a controlling agent lacking
in the isolated star formation process and that stars belonging to a multiple
system do not necessarily evolve in phase with each other.


title:
The Properties and Evolution of a K-band Selected Sample of Massive
  Galaxies at z~0.4 - 2 in the Palomar/DEEP2 Survey

abstract:
  We present the results of a study on the properties and evolution of massive
(M_* > 10^11 M_0) galaxies at z~0.4 - 2 utilising Keck spectroscopy,
near-Infrared Palomar imaging, and Hubble, Chandra, and Spitzer data covering
fields targeted by the DEEP2 galaxy spectroscopic survey. Our sample is K band
selected based on wide-area NIR imaging from the Palomar Observatory Wide-Field
Infrared Survey, which covers 1.53 deg^2 to K_s,vega~20.5. Our major findings
include: (i) statistically the mass and number densities of M_* > 10^11 M_0
galaxies show little evolution between z = 0 - 1, and from z ~ 0 - 2 for M_* >
10^11.5 M_0 galaxies. (ii) Using Hubble ACS imaging, we find that M_* > 10^11
selected galaxies show a nearly constant elliptical fraction of ~70-90% at all
redshifts. The remaining objects are peculiars possibly undergoing mergers at z
> 0.8, while spirals dominate the remainder at lower redshifts. (iii) We find
that only a fraction (~60%) of massive galaxies with M_* > 10^11 M_0 are on the
red-sequence at z~1.4, while nearly 100% evolve onto it by z~0.4. (iv) By
utilising Spitzer MIPS imaging and [OII] line fluxes we argue that M_* >
10^11.5 galaxies have a steeply declining star formation rate density ~(1+z)^6.
By examining the contribution of star formation to the evolution of the mass
function, as well as the merger history through the CAS parameters, we
determine that M_* >10^11 M_0 galaxies undergo on average 0.9^+0.7_-0.5 major
mergers at 0.4 < z < 1.4. (v) A high (5%) fraction of all M_* > 10^11 M_0
galaxies are X-ray emitters. Roughly half of these are morphologically
distorted ellipticals or peculiars. We compare our results with the Millennium
simulation, finding that the number and mass densities of M_* > 10^11.5 M_0
galaxies are under predicted by a factor of > 100.


title:
Single-Molecule Device Prototypes for Protein-Based Nanoelectronics:
  Negative Differential Resistance and Current Rectification in Oligopeptides

abstract:
  We investigate electrical conduction through individual oligopeptide
molecules thiol-bonded between gold nanocontacts using ab initio and
semi-empirical techniques. Our theory explains for the first time these
molecules' experimentally observed current-voltage characteristics, including
both the magnitude and rectification of the current, and uses no adjustable
parameters. We identify the mechanism of the observed current rectification,
and predict that it will result in negative differential resistance at moderate
biases. Our findings open the way to the realization of protein-based
nanoelectronic devices.


title:
Exotic Superconducting Properties in the Electron-Hole Compensated Heavy
  Fermion `Semimetal' URu2Si2

abstract:
  We show that the charge and thermal transport measurements on ultraclean
crystals of URu2Si2 reveal a number of unprecedented superconducting
properties. The uniqueness is best highlighted by the peculiar field dependence
of thermal conductivity including the first order transition at Hc2 with a
reduction of entropy flow. This is a consequence of multi-band
superconductivity with compensated electronic structure in the hidden order
state of this system. We provide strong evidence for a new type of
unconventional superconductivity with two distinct gaps having different nodal
topology.


title:
Form factors and correlation functions of an interacting spinless
  fermion model

abstract:
  Introducing the fermionic R-operator and solutions of the inverse scattering
problem for local fermion operators, we derive a multiple integral
representation for zero-temperature correlation functions of a one-dimensional
interacting spinless fermion model. Correlation functions particularly
considered are the one-particle Green's function and the density-density
correlation function both for any interaction strength and for arbitrary
particle densities. In particular for the free fermion model, our formulae
reproduce the known exact results. Form factors of local fermion operators are
also calculated for a finite system.

categories: cond-mat.stat-mech math-ph math.MP nlin.SI


title:
Aharonov-Bohm Oscillations in Photoluminescence from Charged Exciton in
  Quantum Tubes

abstract:
  The oscillation of photoluminescence peak energies is observed in InAs
quantum tubes depending on the magnetic flux through the tube. The oscillation
is shown to be due to the Aharonov-Bohm effect of a charged exciton in a
quantum tube. No quadratic shift in photoluminescence peak energies is
observed, which is a characteristic feature of a thin quantum tube with a
single channel surrounding the magnetic flux through the tube.


title:
HCN to HCO^+ Millimeter Line Diagnostics of AGN Molecular Torus I :
  Radiative Transfer Modeling

abstract:
  We explore millimeter line diagnostics of an obscuring molecular torus
modeled by a hydrodynamic simulation with three-dimensional nonLTE radiative
transfer calculations. Based on the results of high-resolution hydrodynamic
simulation of the molecular torus around an AGN, we calculate intensities of
HCN and HCO^{+} rotational lines as two representative high density tracers.
The three-dimensional radiative transfer calculations shed light on a
complicated excitation state in the inhomogeneous torus, even though a
spatially uniform chemical structure is assumed. Our results suggest that HCN
must be much more abundant than HCO^{+} in order to obtain a high ratio
($R_{HCN/HCO+}\sim 2$) observed in some of the nearby galaxies. There is a
remarkable dispersion in the relation between integrated intensity and column
density, indicative of possible shortcomings of HCN(1-0) and HCO^{+}(1-0) lines
as high density tracers. The internal structures of the inhomogeneous molecular
torus down to subparsec scale in external galaxies will be revealed by the
forthcoming Atacama Large Millimeter/submillimeter Array (ALMA). The
three-dimensional radiative transfer calculations of molecular lines with
high-resolution hydrodynamic simulation prove to be a powerful tool to provide
a physical basis for molecular line diagnostics of the central regions of
external galaxies.


title: Probe of dark galaxies via disturbed/ lopsided isolated galaxies

abstract:
  Searching for lopsided/interacting objects among ~1500 isolated galaxies
yields only eight strongly disturbed galaxies which may be explained as a
result of their interaction with massive dark objects. We present results of
spectral and photometric observations of these galaxies performed with the 6-m
telescope that lead to significant restriction on cosmic abundance of dark
galaxies.


title: Special K\"ahler-Ricci potentials and Ricci solitons

abstract:
  On a manifold of dimension at least six, let $(g,\tau)$ be a pair consisting
of a K\"ahler metric g which is locally K\"ahler irreducible, and a nonconstant
smooth function $\tau$. Off the zero set of $\tau$, if the metric
$\hat{g}=g/\tau^2$ is a gradient Ricci soliton which has soliton function
$1/\tau$, we show that $\hat{g}$ is K\"ahler with respect to another complex
structure, and locally of a type first described by Koiso. Moreover, $\tau$ is
a special K\"ahler-Ricci potential, a notion defined in earlier works of
Derdzinski and Maschler. The result extends to dimension four with additional
assumptions. We also discuss a Ricci-Hessian equation, which is a
generalization of the soliton equation, and observe that the set of pairs
$(g,\tau)$ satisfying a Ricci-Hessian equation is invariant, in a suitable
sense, under the map $(g,\tau)\to (\hat{g},1/\tau)$.


title: Singular and tangent slit solutions to the Loewner equation

abstract:
  We consider the Loewner differential equation generating univalent maps of
the unit disk (or of the upper half-plane) onto itself minus a single slit. We
prove that the circular slits, tangent to the real axis are generated by
H\"older continuous driving terms with exponent 1/3 in the Loewner equation.
Singular solutions are described, and the critical value of the norm of driving
terms generating quasisymmetric slits in the disk is obtained.


title:
An Interval Analysis Based Study for the Design and the Comparison of
  3-DOF Parallel Kinematic Machines

abstract:
  This paper addresses an interval analysis based study that is applied to the
design and the comparison of 3-DOF parallel kinematic machines. Two design
criteria are used, (i) a regular workspace shape and, (ii) a kinetostatic
performance index that needs to be as homogeneous as possible throughout the
workspace. The interval analysis based method takes these two criteria into
account: on the basis of prescribed kinetostatic performances, the workspace is
analysed to find out the largest regular dextrous workspace enclosed in the
Cartesian workspace. An algorithm describing this method is introduced. Two
3-DOF translational parallel mechanisms designed for machining applications are
compared using this method. The first machine features three fixed linear
joints which are mounted orthogonally and the second one features three linear
joints which are mounted in parallel. In both cases, the mobile platform moves
in the Cartesian x-y-z space with fixed orientation.


title: Pulsars: Progress, Problems and Prospects

abstract:
  I survey recent successes in the application of relativistic MHD and
force-free electrodynamics to the modeling of the pulsars' rotational energy
loss mechanism as well as to the structure and emission characteristics of
Pulsar Wind Nebulae. I suggest that unsteady reconnection in the current sheet
separating the closed from the open zones of the magnetosphere is responsible
for the torque fluctuations observed in some pulsars, as well as for departures
of the braking index from the canonical value of 3. I emphasize the
significance of the boundary layer between the closed and open zones as the
active site in the outer magnetopshere. I elaborate on the conflict between the
models currently in use to interpret the gamma ray and X-ray pulses from these
systems with the electric current flows found in the spin down models. Because
the polar cap ``gap'' is the essential component in the supply of plasma to
pulsar magnetospheres and to pulsar wind nebulae, I emphasize the importance of
high sensitivity gamma ray observations of pulsars with core components of
radio emission and high magnetospheric voltage, since these observations will
look directly into the polar plasma production region. I also discuss the shock
conversion of flow energy into the spectra of the synchrotron emitting
particles in the Nebulae. I comment on the prospects for future developments
and improvements in all these areas.


title: Deconvolution by simulation

abstract:
  Given samples (x_1,...,x_m) and (z_1,...,z_n) which we believe are
independent realizations of random variables X and Z respectively, where we
further believe that Z=X+Y with Y independent of X, the problem is to estimate
the distribution of Y. We present a new method for doing this, involving
simulation. Experiments suggest that the method provides useful estimates.


title: Trace Anomaly Inflation in Brane Induced Gravity

abstract:
  In the present letter we find that Starobinsky's inflationary solution is
also valid in the Dvali-Gabadadze-Porrati (DGP) model where a 3-brane is
embedded in 5-dimensional Minkowski bulk. We show that such a solution is
typically not supported by the Self-Accelerated branch of the model, giving
therefore a natural selection of the conventional branch of solutions. In the
absence of brane induced Einstein-Hilbert term the SA branch is always selected
out. We then study the linearized modes around all such de Sitter brane
solutions finding perturbative stability for a range of parameters of the brane
QFT.


title:
Spatial distribution and galactic model parameters of cataclysmic
  variables

abstract:
  The spatial distribution, galactic model parameters and luminosity function
of cataclysmic variables (CVs) in the solar neighbourhood have been determined
from a carefully established sample of 459 CVs. The sample contains all of the
CVs with distances computed from the Period-Luminosity-Colours (PLCs) relation
of CVs which has been recently derived and calibrated with {\em 2MASS}
photometric data. It has been found that an exponential function fits best to
the observational z-distributions of all of the CVs in the sample, non-magnetic
CVs and dwarf novae, while the sech^{2} function is more appropriate for
nova-like stars and polars. The vertical scaleheight of CVs is 158$\pm$14 pc
for the {\em 2MASS} J-band limiting apparent magnitude of 15.8. On the other
hand, the vertical scaleheights are 128$\pm$20 and 160$\pm$5 pc for dwarf novae
and nova-like stars, respectively. The local space density of CVs is found to
be $\sim3\times10^{-5}$ pc^{-3} which is in agreement with the lower limit of
the theoretical predictions. The luminosity function of CVs shows an increasing
trend toward higher space densities at low luminosities, implying that the
number of short-period systems should be high. The discrepancies between the
theoretical and observational population studies of CVs will almost disappear
if for the z-dependence of the space density the sech^{2} density function is
used.


title: Shape restricted regression with random Bernstein polynomials

abstract:
  Shape restricted regressions, including isotonic regression and concave
regression as special cases, are studied using priors on Bernstein polynomials
and Markov chain Monte Carlo methods. These priors have large supports, select
only smooth functions, can easily incorporate geometric information into the
prior, and can be generated without computational difficulty. Algorithms
generating priors and posteriors are proposed, and simulation studies are
conducted to illustrate the performance of this approach. Comparisons with the
density-regression method of Dette et al. (2006) are included.


title: A Catalog of New M33 Star Clusters Based on the HST/WFPC2 Images

abstract:
  We present the result of a survey for star clusters in M33 using the
HST/WFPC2 archive images. We have found 104 star clusters, including 32 new
ones, in the images of 24 fields that were not included in the previous
studies. Combining these with previous data in the literature, we increase the
number of M33 star clusters found in the HST images to 242. We have derived BVI
integrated photometry of these star clusters from the CCD images taken with
CFH12k mosaic camera at CFHT. Integrated color-magnitude diagrams of the M33
star clusters are found to be similar in general to those of star clusters in
the Large Magellanic Cloud, except that M33 has a much lower fraction of blue
star clusters. We find 29 red star clusters with 0.5 <= (B-V)_0 <= 1.1 and 0.7
<=(V-I)_0 <= 1.2, which are old globular cluster candidates. We divide the
cluster sample into three groups according to their (B-V)_0 color: blue star
clusters with (B-V)_0 <= 0.3, intermediate color star clusters with 0.3 <
(B-V)_0 <0.5, and red star clusters with (B-V)_0 >= 0.5. Most of the new
clusters in M33 are located along the sequence that is consistent with the
theoretical evolutionary path for Z=0.004, Y=0.24 in the (B-V)_0--(V-I)_0
diagram, while a few of them are in the redder side in the (V-I)_0 color. The
red clusters are found relatively more in the outer region of M33 than the blue
and intermediate color clusters, and that many of the blue stars are located in
the HII regions. The luminosity function for the blue star clusters shows a
peak at Mv ~ -7.3 mag, while that for the intermediate color star cluster shows
a peak at the fainter magnitude Mv ~ -6.3 mag. The luminosity function for the
red star clusters shows also a peak at Mv ~ -6.8 mag, although the number of
the clusters is small.


title:
Suppression of Tunneling of Superconducting Vortices Caused by a Remote
  Gate: Example of an Extended Object Tunneling

abstract:
  We discuss a recent experiment in which the resistance of a superconducting
film has been measured in magnetic field. A strong decrease of the
superconducting film resistance has been observed when a metallic gate is
placed above the film. We study how the magnetic coupling between vortices in a
thin superconducting film and electrons in a remote unbiased gate suppresses
the tunneling rate of the vortices. We examine two general approaches to
analyze tunneling in the presence of slow low-energy degrees of freedom: the
functional-integral and scattering formalisms. In the first one, the response
of the electrons inside the metallic gate to a change in the vortex position is
described by the "tunneling with dissipation". We consider the Eddy current
induced in the gate by the magnetic flux of the vortex as a result of
tunneling. In the second approach, the response is given in terms of scattering
of the electrons by the magnetic flux of the vortex in a way similar to the
Aharonov-Bohm scattering. A sudden change in the vortex position leads to the
Orthogonality Catastrophe that opposes the vortex tunneling. We show that the
magnetic coupling between the vortices and the electrons inside the gate can
lead to a dramatic suppression of the vortex tunneling, restoring the
superconducting property in accord with the experiment.


title: Dpes massless QCD have vacuum energy?

abstract:
  It is widely thought that this question has a positive answer, but we argue
that the support for this belief from both experiment and theory is weak or
nonexistent. We then list some of the ramifications of a negative answer.


title:
Non- and semi-parametric analysis of failure time data with missing
  failure indicators

abstract:
  A class of estimating functions is introduced for the regression parameter of
the Cox proportional hazards model to allow unknown failure statuses on some
study subjects. The consistency and asymptotic normality of the resulting
estimators are established under mild conditions. An adaptive estimator which
achieves the minimum variance-covariance bound of the class is constructed.
Numerical studies demonstrate that the asymptotic approximations are adequate
for practical use and that the efficiency gain of the adaptive estimator over
the complete-case analysis can be quite substantial. Similar methods are also
developed for the nonparametric estimation of the survival function of a
homogeneous population and for the estimation of the cumulative baseline hazard
function under the Cox model.


title:
Two non-commutative parameters and regular cosmological phase transition
  in the semi-classical dilaton cosmology

abstract:
  We study cosmological phase transitions from modified equations of motion by
introducing two non-commutative parameters in the Poisson brackets, which
describes the initial- and future-singularity-free phase transition in the
soluble semi-classical dilaton gravity with a non-vanishing cosmological
constant. Accelerated expansion and decelerated expansion corresponding to the
FRW phase appear alternatively, and then it ends up with the second accelerated
expansion. The final stage of the universe approaches the flat spacetime
independent of the initial state of the curvature scalar as long as the product
of the two non-commutative parameters is less than one. Finally, we show that
the initial-singularity-free condition is related to the second accelerated
expansion of the universe.


title:
Coherent Electron Scattering Captured by an Attosecond Quantum
  Stroboscope

abstract:
  The basic properties of atoms, molecules and solids are governed by electron
dynamics which take place on extremely short time scales. To measure and
control these dynamics therefore requires ultrafast sources of radiation
combined with efficient detection techniques. The generation of extreme
ultraviolet (XUV) attosecond (1 as = 10-18 s) pulses has, for the first time,
made direct measurements of electron dynamics possible. Nevertheless, while
various applications of attosecond pulses have been demonstrated
experimentally, no one has yet captured or controlled the full three
dimensional motion of an electron on an attosecond time scale. Here we
demonstrate an attosecond quantum stroboscope capable of guiding and imaging
electron motion on a sub-femtosecond (1 fs = 10-15 s) time scale. It is based
on a sequence of identical attosecond pulses which are synchronized with a
guiding laser field. The pulse to pulse separation in the train is tailored to
exactly match an optical cycle of the laser field and the electron momentum
distributions are detected with a velocity map imaging spectrometer (VMIS).
This technique has enabled us to guide ionized electrons back to their parent
ion and image the scattering event. We envision that coherent electron
scattering from atoms, molecules and surfaces captured by the attosecond
quantum stroboscope will complement more traditional scattering techniques
since it provides high temporal as well as spatial resolution.


title:
Nonparametric estimation of a distribution function under biased
  sampling and censoring

abstract:
  This paper derives the nonparametric maximum likelihood estimator (NPMLE) of
a distribution function from observations which are subject to both bias and
censoring. The NPMLE is obtained by a simple EM algorithm which is an extension
of the algorithm suggested by Vardi (Biometrika, 1989) for size biased data.
Application of the algorithm to many models is discussed and a simulation study
compares the estimator's performance to that of the product-limit estimator
(PLE). An example demonstrates the utility of the NPMLE to data where the PLE
is inappropriate.


title:
Controlled-NOT for multiparticle qubits and topological quantum
  computation based on parity measurements

abstract:
  We discuss a measurement-based implementation of a controlled-NOT (CNOT)
quantum gate. Such a gate has recently been discussed for free electron qubits.
Here we extend this scheme for qubits encoded in product states of two (or
more) spins-1/2 or in equivalent systems. The key to such an extension is to
find a feasible qubit-parity meter. We present a general scheme for reducing
this qubit-parity meter to a local spin-parity measurement performed on two
spins, one from each qubit. Two possible realizations of a multiparticle CNOT
gate are further discussed: electron spins in double quantum dots in the
singlet-triplet encoding, and nu=5/2 Ising non-Abelian anyons using topological
quantum computation braiding operations and nontopological charge measurements.


title: Onset of ferromagnetism in low-doped GaMnAs

abstract:
  We develop a quantitatively predictive theory for impurity-band
ferromagnetism in the low-doping regime of GaMnAs and compare with experimental
measurements of a series of samples whose compositions span the transition from
paramagnetic insulating to ferromagnetic conducting behavior. The theoretical
Curie temperatures depend sensitively on the local fluctuations in the Mn-hole
binding energy, which originates from disorder in the Mn distribution as well
as the presence of As antisite defects. The experimentally-determined hopping
energy at the Curie temperature is roughly constant over a series of samples
whose conductivities vary more than 10^4 and whose hole concentrations vary
more than 10^2. Thus in this regime the hopping energy is an excellent
predictor of the Curie temperature for a sample, in agreement with the theory.


title: Estimating a Polya frequency function_2

abstract:
  We consider the non-parametric maximum likelihood estimation in the class of
Polya frequency functions of order two, viz. the densities with a concave
logarithm. This is a subclass of unimodal densities and fairly rich in general.
The NPMLE is shown to be the solution to a convex programming problem in the
Euclidean space and an algorithm is devised similar to the iterative convex
minorant algorithm by Jongbleod (1999). The estimator achieves Hellinger
consistency when the true density is a PFF_2 itself.


title: A super Frobenius formula for the characters of Iwahori-Hecke algebras

abstract:
  We establish a super Frobenius formula for the characters of Iwahori-Hecke
algebras. We show that the Hall-Littlewood sypersymmetric function, up to
constant, generates the values of the irreducible characters of Iwahori-Hecke
algebras at the elements corresponding to cycle permutations. Our formula in
this article includes both the ordinary quantum case and the classical super
case.


title:
Observation of the first gravitational microlensing event in a sparse
  stellar field : the Tago event

abstract:
  We report the observation of the first gravitational microlensing event in a
sparse stellar field, involving the brightest (V=11.4 mag) andclosest (~ 1 kpc)
source star to date. This event was discovered by an amateurastronomer, A.
Tago, on 2006 October 31 as a transient brightening, by ~4.5 mag during a ~15
day period, of a normal A-type star (GSC 3656-1328) in the Cassiopeia
constellation. Analysis of both spectroscopic observations and the light curve
indicates that this event was caused by gravitational microlensing rather than
an intrinsically variable star. Discovery of this single event over a 30 year
period is roughly consistent with the expected microlensing rate for the whole
sky down to V = 12 mag stars. However, the probability for finding events with
such a high magnification (~ 50) is much smaller, by a factor ~1/50, which
implies that the true event rate may be higher than expected. This discovery
indicates the potential of all sky variability surveys, employing frequent
sampling by telescopes with small apertures and wide fields of view, for
finding such rare transient events, and using the observations to explore
galactic disk structure and search for exo-planets.


title:
Interacting RNA polymerase motors on DNA track: effects of traffic
  congestion and intrinsic noise on RNA synthesis

abstract:
  RNA polymerase (RNAP) is an enzyme that synthesizes a messenger RNA (mRNA)
strand which is complementary to a single-stranded DNA template. From the
perspective of physicists, an RNAP is a molecular motor that utilizes chemical
energy input to move along the track formed by a DNA. In many circumstances,
which are described in this paper, a large number of RNAPs move simultaneously
along the same track; we refer to such collective movements of the RNAPs as
RNAP traffic. Here we develop a theoretical model for RNAP traffic by
incorporating the steric interactions between RNAPs as well as the
mechano-chemical cycle of individual RNAPs during the elongation of the mRNA.
By a combination of analytical and numerical techniques, we calculate the rates
of mRNA synthesis and the average density profile of the RNAPs on the DNA
track. We also introduce, and compute, two new measures of fluctuations in the
synthesis of RNA. Analyzing these fluctuations, we show how the level of {\it
intrinsic noise} in mRNA synthesis depends on the concentrations of the RNAPs
as well as on those of some of the reactants and the products of the enzymatic
reactions catalyzed by RNAP. We suggest appropriate experimental systems and
techniques for testing our theoretical predictions.


title: Capability of multi-detector analyses on supernova neutrinos

abstract: This paper has been withdrawn by the author, due to errors in the figures.


title:
A comparison of the accuracy of saddlepoint conditional cumulative
  distribution function approximations

abstract:
  Consider a model parameterized by a scalar parameter of interest and a
nuisance parameter vector. Inference about the parameter of interest may be
based on the signed root of the likelihood ratio statistic R. The standard
normal approximation to the conditional distribution of R typically has error
of order O(n^{-1/2}), where n is the sample size. There are several
modifications for R, which reduce the order of error in the approximations. In
this paper, we mainly investigate Barndorff-Nielsen's modified directed
likelihood ratio statistic, Severini's empirical adjustment, and DiCiccio and
Martin's two modifications, involving the Bayesian approach and the conditional
likelihood ratio statistic. For each modification, two formats were employed to
approximate the conditional cumulative distribution function; these are
Barndorff-Nielson formats and the Lugannani and Rice formats. All
approximations were applied to inference on the ratio of means for two
independent exponential random variables. We constructed one and two-sided
hypotheses tests and used the actual sizes of the tests as the measurements of
accuracy to compare those approximations.


title: Multivariate medians and measure-symmetrization

abstract:
  We discuss two research areas dealing respectively with (1) a class of
multivariate medians and (2) a symmetrization algorithm for probability
measures.


title: Statistical thinking: From Tukey to Vardi and beyond

abstract:
  Data miners (minors?) and neural networkers tend to eschew modelling, misled
perhaps by misinterpretation of strongly expressed views of John Tukey. I
discuss Vardi's views of these issues as well as other aspects of Vardi's work
in emision tomography and in sampling bias.


title: Deviation from $\Lambda$CDM: Pressure Parametrization

abstract:
  Most parametrizations for dark energy involve the equation of state $w$ of
the dark energy. In this work, we choose the pressure of the dark energy to
parametrize. As $p = constant$ essentially gives a cosmological constant, we
use the Taylor expansion around this behavior $p = -p_{0} + (1-a)p_{1} + ....$
to study the small deviations from the cosmological constant. In our model, the
departure from the cosmological constant behavior has been modeled by the
presence of extra K-essence fields while keeping the cosmological constant term
untouched. The model is similar to assisted inflation scenario in a sense that
for any higher order deviation in terms of Taylor series expansion, one needs
multiple K-essence fields. We have also tested our model with the recent
observational data coming from Supernova type Ia measurements, the baryon
oscillations peak (BAO) and the gas mass fraction of the galaxy clusters
inferred from X-ray observations and obtain constraints for our model
parameters.


title:
Errors Theory using Dirichlet Forms, Linear Partial Differential
  Equations and Wavelets

abstract:
  We present an application of error theory using Dirichlet Forms in linear
partial differential equations (LPDE). We study the transmission of an
uncertainty on the terminal condition to the solution of the LPDE thanks to the
decomposition of the solution on a wavelets basis. We analyze the basic
properties and a particular class of LPDE where the wavelets bases show their
powerful, the combination of error theory and wavelets basis justifies some
hypotheses, helpful to simplify the computation.


title:
Model calculation of orientational effect of deformed aerogel on the
  order parameter of superfluid 3He

abstract:
  Theory of Rainer and Vuorio of small objects in superfluid ^3He is applied
for calculation of the average orientational effect of a deformed aerogel on
the order parameter of 3He. The minimum deformation which stabilizes the
ordered state is evaluated both for specular and diffusive scattering of
quasiparticles by the threads of aerogel.


title: N=4 superconformal Calogero models

abstract:
  We continue the research initiated in hep-th/0607215 and apply our method of
conformal automorphisms to generate various N=4 superconformal quantum
many-body systems on the real line from a set of decoupled particles extended
by fermionic degrees of freedom. The su(1,1|2) invariant models are governed by
two scalar potentials obeying a system of nonlinear partial differential
equations which generalizes the Witten-Dijkgraaf-Verlinde-Verlinde equations.
As an application, the N=4 superconformal extension of the three-particle
(A-type) Calogero model generates a unique G_2-type Hamiltonian featuring
three-body interactions. We fully analyze the N=4 superconformal three- and
four-particle models based on the root systems of A_1 + G_2 and F_4,
respectively. Beyond Wyllard's solutions we find a list of new models, whose
translational non-invariance of the center-of-mass motion fails to decouple and
extends even to the relative particle motion.


title: Early evolution of transversally thermalized partons

abstract:
  The idea that the parton system created in relativistic heavy-ion collisions
(i) emerges in a state with transverse momenta close to thermodynamic
equilibrium and (ii) its evolution at early times is dominated by the
2-dimensional (transverse) hydrodynamics of the ideal fluid is investigated. It
is argued that this mechanism may help to solve the problem of early
equilibration.


title: Green-Schwarz superstring from type IIB matrix model

abstract:
  We construct Green-Schwarz (GS) light-cone closed superstring theory from
type IIB matrix model. A GS light-cone string action is derived from two
dimensional N=8 U(n) noncommutative Yang-Mills (NCYM) by identifying
noncommutative scale with string scale. Supersymmetry transformation for the
light-cone gauge action is also derived from supersymmetry transformation for
IIB matrix model. By identifying the physical states and interaction vertices,
string theory is perturbatively reproduced.


title: Nearly MDS expander codes with reduced alphabet size

abstract:
  Recently, Roth and Skachek proposed two methods for constructing nearly
maximum-distance separable (MDS) expander codes. We show that through the
simple modification of using mixed-alphabet codes derived from MDS codes as
constituent codes in their code designs, one can obtain nearly MDS codes of
significantly smaller alphabet size, albeit at the expense of a (very slight)
reduction in code rate.


title: Statistical inverse problems in active network tomography

abstract:
  The analysis of computer and communication networks gives rise to some
interesting inverse problems. This paper is concerned with active network
tomography where the goal is to recover information about quality-of-service
(QoS) parameters at the link level from aggregate data measured on end-to-end
network paths. The estimation and monitoring of QoS parameters, such as loss
rates and delays, are of considerable interest to network engineers and
Internet service providers. The paper provides a review of the inverse problems
and recent research on inference for loss rates and delay distributions. Some
new results on parametric inference for delay distributions are also developed.
In addition, a real application on Internet telephony is discussed.


title:
Constraints on the range lambda of Yukawa-like modifications to the
  Newtonian inverse-square law of gravitation from Solar System planetary
  motions

abstract:
  In this paper we use the latest corrections to the Newton-Einstein secular
perihelion rates of some planets of the Solar System, phenomenologically
estimated with the EPM2004 ephemerides by the Russian astronomer E.V. Pitjeva,
to put severe constraints on the range parameter lambda characterizing the
Yukawa-like modifications of the Newtonian inverse-square law of gravitation.
It turns out that the range cannot exceed about one tenth of an Astronomical
Unit. We assumed neither equivalence principle violating effects nor spatial
variations of $\alpha$ and $\lambda$. This finding may have important
consequences on all the modified theories of gravity involving Yukawa-type
terms with range parameters much larger than the Solar System size. However,
caution is advised since we, currently have at our disposal only the periehlion
extra-rates estimated by Pitjeva: if and when other groups will estimate their
own corrections to the secular motion of perihelia, more robust and firm tests
may be conducted.


title:
Quantifying Resonant Structure in NGC 6946 from Two-dimensional
  Kinematics

abstract:
  We study the two-dimensional kinematics of the H-alpha-emitting gas in the
nearby barred Scd galaxy, NGC 6946, in order to determine the pattern speed of
the primary m=2 perturbation mode. The pattern speed is a crucial parameter for
constraining the internal dynamics, estimating the impact velocities of the
gravitational perturbation at the resonance radii, and to set up an
evolutionary scenario for NGC 6946. Our data allows us to derive the best
fitting kinematic position angle and the geometry of the underlying gaseous
disk, which we use to derive the pattern speed using the Tremaine-Weinberg
method. We find a main pattern speed Omega_p=22 km/s/kpc, but our data clearly
reveal the presence of an additional pattern speed Omega_p=47 km/s/kpc in a
zone within 1.25 kpc of the nucleus. Using the epicyclic approximation, we
deduce the location of the resonance radii and confirm that inside the outer
Inner Lindblad Resonance radius of the main oval, a primary bar has formed
rotating at more than twice the outer pattern speed. We further confirm that a
nuclear bar has formed inside the Inner Lindblad Resonance radius of the
primary bar, coinciding with the inner Inner Lindblad Resonance radius of the
large-scale m=2 mode oval.


title: Q2237+0305 source structure and dimensions from light curves simulation

abstract:
  Assuming a two-component quasar structure model consisting of a central
compact source and an extended outer feature, we produce microlensing
simulations for a population of star-like objects in the lens galaxy. Such a
model is a simplified version of that adopted to explain the brightness
variations observed in Q0957 (Schild & Vakulik 2003). The microlensing light
curves generated for a range of source parameters were compared to the light
curves obtained in the framework of the OGLE program. With a large number of
trials we built, in the domain of the source structure parameters, probability
distributions to find "good" realizations of light curves. The values of the
source parameters which provide the maximum of the joint probability
distribution calculated for all the image components, have been accepted as
estimates for the source structure parameters. The results favour the
two-component model of the quasar brightness structure over a single compact
central source model, and in general the simulations confirm the Schild-Vakulik
model that previously described successfully the microlensing and other
properties of Q0957. Adopting 3300 km/s for the transverse velocity of the
source, the effective size of the central source was determined to be about
2x10^15 cm, and Epsilon =2 was obtained for the ratio of the integral
luminosity of the outer feature to that of the central source.


title:
The Near-Infrared Broad Emission Line Region of Active Galactic Nuclei
  -- I. The Observations

abstract:
  We present high quality (high signal-to-noise ratio and moderate spectral
resolution) near-infrared (near-IR) spectroscopic observations of 23 well-known
broad-emission line active galactic nuclei (AGN). Additionally, we obtained
simultaneous (within two months) optical spectroscopy of similar quality. The
near-IR broad emission line spectrum of AGN is dominated by permitted
transitions of hydrogen, helium, oxygen, and calcium, and by the rich spectrum
of singly-ionized iron. In this paper we present the spectra, line
identifications and measurements, and address briefly some of the important
issues regarding the physics of AGN broad emission line regions. In particular,
we investigate the excitation mechanism of neutral oxygen and confront for the
first time theoretical predictions of the near-IR iron emission spectrum with
observations.


title: Densities for Ornstein-Uhlenbeck processes with jumps

abstract:
  We consider an Ornstein-Uhlenbeck process with values in R^n driven by a
L\'evy process (Z_t) taking values in R^d with d possibly smaller than n. The
L\'evy noise can have a degenerate or even vanishing Gaussian component.
  Under a controllability condition and an assumption on the L\'evy measure of
(Z_t), we prove that the law of the Ornstein-Uhlenbeck process at any time t>0
has a density on R^n. Moreover, when the L\'evy process is of $\alpha$-stable
type, $\alpha \in (0,2)$, we show that such density is a $C^{\infty}$-function.


title:
Using data network metrics, graphics, and topology to explore network
  characteristics

abstract:
  Yehuda Vardi introduced the term network tomography and was the first to
propose and study how statistical inverse methods could be adapted to attack
important network problems (Vardi, 1996). More recently, in one of his final
papers, Vardi proposed notions of metrics on networks to define and measure
distances between a network's links, its paths, and also between different
networks (Vardi, 2004). In this paper, we apply Vardi's general approach for
network metrics to a real data network by using data obtained from special data
network tools and testing procedures presented here. We illustrate how the
metrics help explicate interesting features of the traffic characteristics on
the network. We also adapt the metrics in order to condition on traffic passing
through a portion of the network, such as a router or pair of routers, and show
further how this approach helps to discover and explain interesting network
characteristics.


title:
Recycling of quantum information: Multiple observations of quantum
  systems

abstract:
  Given a finite number of copies of an unknown qubit state that have already
been measured optimally, can one still extract any information about the
original unknown state? We give a positive answer to this question and quantify
the information obtainable by a given observer as a function of the number of
copies in the ensemble, and of the number of independent observers that, one
after the other, have independently measured the same ensemble of qubits before
him. The optimality of the protocol is proven and extensions to other states
and encodings are also studied. According to the general lore, the state after
a measurement has no information about the state before the measurement. Our
results manifestly show that this statement has to be taken with a grain of
salt, specially in situations where the quantum states encode confidential
information.


title: Legendrian ribbons in overtwisted contact structures

abstract:
  We show that a null-homologous transverse knot K in the complement of an
overtwisted disk in a contact 3-manifold is the boundary of a Legendrian ribbon
if and only if it possesses a Seifert surface S such that the self-linking
number of K with respect to S satisfies $\sel(K,S)=-\chi(S)$. In particular,
every null-homologous topological knot type in an overtwisted contact manifold
can be represented by the boundary of a Legendrian ribbon. Finally, we show
that a contact structure is tight if and only if every Legendrian ribbon
minimizes genus in its relative homology class.


title: Wobbles and other kink-breather solutions of the Sine Gordon model

abstract:
  We study various solutions of the Sine Gordon model in (1+1) dimensions. We
use the Hirota method to construct some of them and then show that the wobble,
discussed in detail by K\"alberman, is one of such solutions. We concentrate
our attention on a kink and its bound states with one or two breathers. We
study their stability and some aspects of their scattering properties on
potential wells and on fixed boundary conditions.


title: Quantum criticality as a resource for quantum estimation

abstract:
  We address quantum critical systems as a resource in quantum estimation and
derive the ultimate quantum limits to the precision of any estimator of the
coupling parameters. In particular, if L denotes the size of a system and
\lambda is the relevant coupling parameters driving a quantum phase transition,
we show that a precision improvement of order 1/L may be achieved in the
estimation of \lambda at the critical point compared to the non-critical case.
We show that analogue results hold for temperature estimation in classical
phase transitions. Results are illustrated by means of a specific example
involving a fermion tight-binding model with pair creation (BCS model).


title: Fano resonances at light scattering by an obstacle

abstract:
  It is shown that elastic resonance scattering of light by a finite-size
obstacle with weak dissipation is analogous to quantum scattering by a
potential with quasi-discrete levels and exhibits Fano resonances. Localized
plasmons (polaritons), exited in the obstacle by the incident light, are
equivalent to the quasi-discrete levels, while the radiative decay of these
excitations plays exactly the same role as tunnelling from the quasi-discrete
levels for the quantum problem. Mie scattering of light by a spherical particle
and an exactly solvable discrete model with nonlocal coupling simulating wave
scattering in systems with reduced spatial dimensionality are discussed as
examples.

categories: cond-mat.other cond-mat.mes-hall cond-mat.soft physics.optics


title: Semiclassical Limits of Quantum Affine Spaces

abstract:
  Semiclassical limits of generic multiparameter quantized coordinate rings A =
O_q(k^n) of affine spaces are constructed and related to A, for k an
algebraically closed field of characteristic zero and q a multiplicatively
antisymmetric matrix whose entries generate a torsionfree subgroup of k*. A
semiclassical limit of A is a Poisson algebra structure on the corresponding
classical coordinate ring R = O(k^n), and results of Oh, Park, Shin and the
authors are used to construct homeomorphisms from the Poisson prime and Poisson
primitive spectra of R onto the prime and primitive spectra of A. The Poisson
primitive spectrum of R is then identified with the space of symplectic cores
in k^n in the sense of Brown and Gordon, and an example is presented (over the
complex numbers) for which the Poisson primitive spectrum of R is not
homeomorphic to the space of symplectic leaves in k^n. Finally, these results
are extended from quantum affine spaces to quantum affine toric varieties.


title:
Spin-orbital Kondo decoherence by environmental effects in capacitively
  coupled quantum dot devices

abstract:
  Strong correlation effects in a capacitively coupled double quantum-dot setup
were previously shown to provide the possibility of both entangling spin-charge
degrees of freedom and realizing efficient spin-filtering operations by static
gate-voltage manipulations. Motivated by the use of such a device for quantum
computing, we study the influence of electromagnetic noise on a general
spin-orbital Kondo model, and investigate the conditions for observing
coherent, unitary transport, crucial to warrant efficient spin manipulations.
We find a rich phase diagram, where low-energy properties sensitively depend on
the impedance of the external environment and geometric parameters of the
system. Relevant energy scales related to the Kondo temperature are also
computed in a renormalization-group treatment, allowing to assess the
robustness of the device against environmental effects.


title: Nuclear Star Clusters across the Hubble Sequence

abstract:
  Over the last decade, HST imaging studies have revealed that the centers of
most galaxies are occupied by compact, barely resolved sources. Based on their
structural properties, position in the fundamental plane, and spectra, these
sources clearly have a stellar origin. They are therefore called ``nuclear star
clusters'' (NCs) or ``stellar nuclei''. NCs are found in galaxies of all Hubble
types, suggesting that their formation is intricately linked to galaxy
evolution. In this contribution, I briefly review the results from recent
studies of NCs, touch on some ideas for their formation, and mention some open
issues related to the possible connection between NCs and supermassive black
holes.


title:
Threshold Resonant Structure of the 232Th Neutron-Induced Fission Cross
  Section

abstract:
  The structures observed in the sub-threshold neutron-induced fission of
^{232}Th were investigated employing a recent developed model. Theoretical
single-particle excitations of a phenomenological two-humped barrier are
determined by solving a system of coupled differential equations for the motion
along the optimal fission path. A rather good agreement with experimental data
was obtained using a small number of independent parameters. It is predicted
that the structure at 1.4 and 1.6 MeV is mainly dominated by spin 3/2 partial
cross-section with small admixture of spin 1/2, while the structure at 1.7 MeV
is given by a large partial cross section of spin 5/2.


title: Quantum turbulence in propagating superfluid vortex front

abstract:
  We present experimental, numerical and theoretical studies of a vortex front
propagating into a region of vortex-free flow of rotating superfluid 3He-B. We
show that the nature of the front changes from laminar through quasi-classical
turbulent to quantum turbulent with decreasing temperature. Our experiment
provides the first direct measurement of the dissipation rate in turbulent
vortex dynamics of 3He-B and demonstrates that the dissipation is temperature-
and mutual friction-independent in the T->0 limit, and is strongly suppressed
when the Kelvin-wave cascade on vortex lines is predicted to be involved in the
turbulent energy transfer to smaller length scales.


title: Pseudo-Riemannian Jacobi-Videv Manifolds

abstract:
  We exhibit several families of Jacobi-Videv pseudo-Riemannian manifolds which
are not Einstein. We also exhibit Jacobi-Videv algebraic curvature tensors
where the Ricci operator defines an almost complex structure.


title: Effects of the network structural properties on its controllability

abstract:
  In a recent paper, it has been suggested that the controllability of a
diffusively coupled complex network, subject to localized feedback loops at
some of its vertices, can be assessed by means of a Master Stability Function
approach, where the network controllability is defined in terms of the spectral
properties of an appropriate Laplacian matrix. Following that approach, a
comparison study is reported here among different network topologies in terms
of their controllability. The effects of heterogeneity in the degree
distribution, as well as of degree correlation and community structure, are
discussed.