title:
Generalising the Ginsparg-Wilson relation: Lattice Supersymmetry from
  Blocking Transformations

abstract:
  The Ginsparg-Wilson relation is extended to interacting field theories with
general linear symmetries. Our relation encodes the remnant of the original
symmetry in terms of the blocked fields and guides the construction of
invariant lattice actions. We apply this approach in the case of lattice
supersymmetry. An additional constraint has to be satisfied because of the
appearance of a derivative operator in the symmetry transformations. The
solution of this constraint leads to non-local SLAC-type derivatives. We
investigate the corresponding kinetic operators on the lattice within an exact
solution of supersymmetric quantum mechanics. These solutions - analogues of
the overlap operator for supersymmetry - can be made local through a specific
choice of the blocking kernel. We show that the corresponding relation allows
for local lattice symmetry operators as well as local lattice actions. We argue
that for interacting theories the lattice action is polynomial in the fields
only under special circumstances, which is exemplified within an exact
solution.


title: Hot Spacetimes for Cold Atoms

abstract:
  Building on our earlier work and that of Son, we construct string theory
duals of non-relativistic critical phenomena at finite temperature and density.
Concretely, we find black hole solutions of type IIB supergravity whose
asymptotic geometries realize the Schroedinger group as isometries. We then
identify the non-relativistic conformal field theories to which they are dual.
We analyze the thermodynamics of these black holes, which turn out to describe
the system at finite temperature and finite density. The strong-coupling result
for the shear viscosity of the dual non-relativistic field theory saturates the
KSS bound.


title:
SDSS J142625.71+575218.3: The First Pulsating White Dwarf with a Large
  Detectable Magnetic Field

abstract:
  We report the discovery of a strong magnetic field in the unique pulsating
carbon-atmosphere white dwarf SDSS J142625.71+575218.3. From spectra gathered
at the MMT and Keck telescopes, we infer a surface field of B_s ~1.2 MG, based
on obvious Zeeman components seen in several carbon lines. We also detect the
presence of a Zeeman-splitted He I 4471 line, which is an indicator of the
presence of a non-negligible amount of helium in the atmosphere of this Hot DQ
star. This is important for understanding its pulsations, as nonadabatic theory
reveals that some helium must be present in the envelope mixture for pulsation
modes to be excited in the range of effective temperature where the target star
is found. Out of nearly 200 pulsating white dwarfs known today, this is the
first example of a star with a large detectable magnetic field. We suggest that
SDSS J142625.71+575218.3 is the white dwarf equivalent of a roAp star.


title: CMB power spectrum estimation using wavelets

abstract:
  Observations of the Cosmic Microwave Background (CMB) provide increasingly
accurate information about the structure of the Universe at the recombination
epoch. Most of this information is encoded in the angular power spectrum of the
CMB. The aim of this work is to propose a versatile and powerful method for
spectral estimation on the sphere which can easily deal with non-stationarity,
foregrounds and multiple experiments with various specifications. In this
paper, we use needlets (wavelets) on the sphere to construct natural and
efficient spectral estimators for partially observed and beamed CMB with non
stationary noise. In the case of a single experiment, we compare this method
with Pseudo-$C_\ell$ methods. The performance of the needlet spectral
estimators (NSE) compares very favorably to the best Pseudo--$C_\ell$
estimators, over the whole multipole range. On simulations with a simple model
(CMB + uncorrelated noise with known variance per pixel + mask), they perform
uniformly better. Their distinctive ability to aggregate many different
experiments, to control the propagation of errors and to produce a single
wide-band error bars is highlighted. The needlet spectral estimator is a
powerful, tunable tool which is very well suited to angular power spectrum
estimation of spherical data such as incomplete and noisy CMB maps.


title: From Grains to Planetesimals: Les Houches Lecture

abstract:
  This pedagogical review covers an unsolved problem in the theory of
protoplanetary disks: the growth of dust grains into planetesimals, solids at
least a kilometer in size. I summarize timescale constraints imposed on
planetesimal formation by circumstellar disk observations, analysis of
meteorites, and aerodynamic radial migration. The infall of ~meter-sized solids
in a hundred years is the most stringent constraint. I review proposed
mechanisms for planetesimal formation. Collisional coagulation models are
informed by laboratory studies of microgravity collisions. The gravitational
collapse (or Safronov-Goldreich-Ward) hypothesis involves detailed study of the
interaction between solid particles and turbulent gas. I cover the basics of
aerodynamic drag in protoplanetary disks, including radial drift and vertical
sedimentation. I describe various mechanisms for particle concentration in gas
disks -- including turbulent pressure maxima, drag instabilities and long-lived
anticylonic vortices. I derive a general result for the minimum size for a
vortex to trap particles in a sub-Keplerian disk. Recent numerical simulations
demonstrate that particle clumping in turbulent protoplanetary disks can
trigger gravitational collapse. I discuss several outstanding issues in the
field.


title:
Morphologies of High Redshift, Dust Obscured Galaxies from Keck Laser
  Guide Star Adaptive Optics

abstract:
  Spitzer MIPS images in the Bootes field of the NOAO Deep Wide-Field Survey
have revealed a class of extremely dust obscured galaxy (DOG) at z~2. The DOGs
are defined by very red optical to mid-IR (observed-frame) colors, R - [24 um]
> 14 mag, i.e. f_v (24 um) / f_v (R) > 1000. They are Ultra-Luminous Infrared
Galaxies with L_8-1000 um > 10^12 -10^14 L_sun, but typically have very faint
optical (rest-frame UV) fluxes. We imaged three DOGs with the Keck Laser Guide
Star Adaptive Optics (LGSAO) system, obtaining ~0.06'' resolution in the
K'-band. One system was dominated by a point source, while the other two were
clearly resolved. Of the resolved sources, one can be modeled as a exponential
disk system. The other is consistent with a de Vaucouleurs profile typical of
elliptical galaxies. The non-parametric measures of their concentration and
asymmetry, show the DOGs to be both compact and smooth. The AO images rule out
double nuclei with separations of greater than 0.1'' (< 1 kpc at z=2), making
it unlikely that ongoing major mergers (mass ratios of 1/3 and greater) are
triggering the high IR luminosities. By contrast, high resolution images of z~2
SCUBA sources tend to show multiple components and a higher degree of
asymmetry. We compare near-IR morphologies of the DOGs with a set of z=1
luminous infrared galaxies (LIRGs; L_IR ~ 10^11 L_sun) imaged with Keck LGSAO
by the Center for Adaptive Optics Treasury Survey. The DOGs in our sample have
significantly smaller effective radii, ~1/4 the size of the z=1 LIRGs, and tend
towards higher concentrations. The small sizes and high concentrations may help
explain the globally obscured rest-frame blue-to-UV emission of the DOGs.


title: Simulations of XUV Disks with a Star Formation Density Threshold

abstract:
  The outer regions of disk galaxies show a drop-off in optical and Halpha
emission, suggesting a star formation threshold radius, assumed to owe to a
critical surface density below which star formation does not take place. Signs
of filamentary star formation beyond this threshold radius have been observed
in individual galaxies in the Halpha and recent GALEX surveys have discovered
that 30% of disk galaxies show UV emission out to 2-3 times the optical radius
of the galaxy. We run smooth particle hydrodynamics simulations of disk
galaxies with constant density extended gas disks to test whether
over-densities owing to spiral structure in the outer disk can reproduce the
observed star formation. We indeed find that spiral density waves from the
inner disk propagate into the outer gas disk and raise local gas regions above
the star formation density threshold, yielding features similar to those
observed. Because the amount of star formation is low, we expect to see little
optical emission in outer disks, as observed. Our results indicate that XUV
disks can be simulated simply by adding an extended gas disk with a surface
density near the threshold density to an isolated galaxy and evolving it with
fiducial star formation parameters.


title: The Schwinger mechanism revisited

abstract:
  The vacuum persistence probability, $P_{vac}(t)$, for a system of charged
fermions in a fixed, external, and spatially homogeneous electric field, was
derived long ago by Schwinger; $w = -log[P_{vac}(t)]/ (V t)$ has often been
identified as the rate at which fermion-antifermion pairs are produced per unit
volume due to the electric field. In this paper, we separately compute exact
expressions for both $w$ and for the rate of fermion-antifermion pair
production per unit volume, $\Gamma$, and show that they differ. While $w$ is
given by the standard Schwinger mechanism result $w$, an infinite series, the
pair production rate, $\Gamma$, is just the first term of that series. Our
calculation is done for a system with periodic boundary conditions in the
$A_0=0$ gauge but the result should hold for any consistent set of boundary
conditions. We discuss, the physical reason why the rates $w$ and $\Gamma$
differ.


title:
Enhancement of Entanglement Percolation in Quantum Networks via Lattice
  Transformations

abstract:
  We study strategies for establishing long-distance entanglement in quantum
networks. Specifically, we consider networks consisting of regular lattices of
nodes, in which the nearest neighbors share a pure, but non-maximally entangled
pair of qubits. We look for strategies that use local operations and classical
communication. We compare the classical entanglement percolation protocol, in
which every network connection is converted with a certain probability to a
singlet, with protocols in which classical entanglement percolation is preceded
by measurements designed to transform the lattice structure in a way that
enhances entanglement percolation. We analyze five examples of such comparisons
between protocols and point out certain rules and regularities in their
performance as a function of degree of entanglement and choice of operations.


title:
The origin of hydrogen line emission for five Herbig Ae/Be stars
  spatially resolved by VLTI/AMBER spectro-interferometry

abstract:
  To trace the accretion and outflow processes around YSOs, diagnostic spectral
lines such as the BrG 2.166 micron line are widely used, although due to a lack
of spatial resolution, the origin of the line emission is still unclear.
Employing the AU-scale spatial resolution which can be achieved with infrared
long-baseline interferometry, we aim to distinguish between theoretical models
which associate the BrG line emission with mass infall or mass outflow
processes. Using the VLTI/AMBER instrument, we spatially and spectrally
(R=1500) resolved the inner environment of five Herbig Ae/Be stars (HD163296,
HD104237, HD98922, MWC297, V921Sco) in the BrG emission line as well as in the
adjacent continuum. All objects (except MWC297) show an increase of visibility
within the BrG emission line, indicating that the BrG-emitting region in these
objects is more compact than the dust sublimation radius. For HD98922, our
quantitative analysis reveals that the line-emitting region is compact enough
to be consistent with the magnetospheric accretion scenario. For HD163296,
HD104237, MWC297, and V921Sco we identify a stellar wind or a disk wind as the
most likely line-emitting mechanism. We search for general trends and find that
the size of the BrG-emitting region does not seem to depend on the basic
stellar parameters, but correlates with the H-alpha line profile shape. We find
evidence for at least two distinct BrG line-formation mechanisms. Stars with a
P-Cygni H-alpha line profile and a high mass-accretion rate seem to show
particularly compact BrG-emitting regions (R_BrG/R_cont<0.2), while stars with
a double-peaked or single-peaked H-alpha-line profile show a significantly more
extended BrG-emitting region (0.6<R_BrG/R_cont<1.4), possibly tracing a stellar
wind or a disk wind.


title: On cutoff effects in lattice QCD from short to long distances

abstract:
  We discuss kinematical enhancements of cutoff effects at short and
intermediate distances. Starting from a pedagogical example with periodic
boundary conditions, we switch to the case of the Schroedinger Functional,
where the theoretical analysis is checked by precise numerical data with Nf=2
dynamical O(a)-improved Wilson quarks. Finally we present an improved
determination of the renormalization of the axial current in that theory.


title:
Sensitivity to anomalous quartic gauge couplings in photon-photon
  interactions at the LHC

abstract:
  The exclusive two-photon production at the LHC of pairs of W and Z bosons
provides a novel and unique test-ground for the electroweak gauge boson sector.
In particular it offers, thanks to high gamma-gamma center-of-mass energies,
large and direct sensitivity to the anomalous quartic gauge couplings otherwise
very difficult to investigate at the LHC. An initial analysis has been
performed assuming leptonic decays and generic acceptance cuts. Simulation of a
simple counting experiment has shown for the integrated luminosity of 10 fb-1
at least four thousand times larger sensitivity to the genuine quartic
couplings, a_0^W, a_0^Z, a_C^W and a_C^Z, than those obtained at LEP. The
impact of the unitarity constraints on the estimated limits has been studied
using the dipole form-factors. Finally, differential distributions of the decay
leptons have been provided to illustrate the potential for further improvements
of the sensitivities.


title:
Numerical experiments on dynamo action in sheared and rotating
  turbulence

abstract:
  Numerical simulations of forced turbulence in elongated shearing boxes are
carried out to demonstrate that a nonhelical turbulence in conjunction with a
linear shear can give rise to a mean-field dynamo. Exponential growth of
magnetic field at scales larger than the outer (forcing) scale of the
turbulence is found. Over a range of values of the shearing rate S spanning
approximately two orders of magnitude, the growth rate of the magnetic field is
proportional to the imposed shear, gamma ~ S, while the characteristic spatial
scale of the field is l_b ~ S^(-1/2). The effect is quite general: earlier
results for the nonrotating case by Yousef et al. 2008 (PRL 100, 184501) are
extended to shearing boxes with Keplerian rotation; it is also shown that the
shear dynamo mechanism operates both below and above the threshold for the
fluctuation dynamo. The apparently generic nature of the shear dynamo effect
makes it an attractive object of study for the purpose of understanding the
generation of magnetic fields in astrophysical systems.


title:
Infinite Randomness Phases and Entanglement Entropy of the Disordered
  Golden Chain

abstract:
  Topological insulators supporting non-abelian anyonic excitations are at the
center of attention as candidates for topological quantum computation. In this
paper, we analyze the ground-state properties of disordered non-abelian anyonic
chains. The resemblance of fusion rules of non-abelian anyons and real space
decimation strongly suggests that disordered chains of such anyons generically
exhibit infinite-randomness phases. Concentrating on the disordered golden
chain model with nearest-neighbor coupling, we show that Fibonacci anyons with
the fusion rule $\tau\otimes\tau={\bf 1}\oplus \tau$ exhibit two
infinite-randomness phases: a random-singlet phase when all bonds prefer the
trivial fusion channel, and a mixed phase which occurs whenever a finite
density of bonds prefers the $\tau$ fusion channel. Real space RG analysis
shows that the random-singlet fixed point is unstable to the mixed fixed point.
By analyzing the entanglement entropy of the mixed phase, we find its effective
central charge, and find that it increases along the RG flow from the random
singlet point, thus ruling out a c-theorem for the effective central charge.


title:
A cosmologically motivated description of the dark matter halo profile
  for the Low Surface Brightness Galaxy, Malin 1

abstract:
  In this paper we derive a possible mass profile for the low surface
brightness galaxy, Malin 1, based upon previously published space-based and
ground-based photometric properties and kinematics. We use properties of the
bulge, normal disk, outer extended disk and \ion{H}{1} mass as inputs into mass
profile models. We find that the dark matter halo model of Malin 1 is best
described by a halo profile that has undergone adiabatic contraction,
inconsistent with the findings for most disk galaxies to date, yet consistent
with rotation curve studies of M31. More importantly, we find that Malin 1 is
baryon dominated in its central regions out to a radius of $\sim10$ kpc (in the
bulge region). Low-surface brightness galaxies are often referred to as being
dark matter dominated at all radii. If this is the case, then Malin 1 would
seem to have characteristics similar to those of normal barred disk galaxies,
as suggested by other recent work. We also find that Malin 1 also falls on the
rotation curve shear versus spiral arm pitch angle relation for normal
galaxies, although more LSB galaxies need to be studied to determine if this is
typical.


title: A Precision Measurement of the Muon Decay Parameters $\rho$ and $\delta$

abstract:
  The TWIST collaboration has performed new measurements of two of the
parameters that describe muon decay: $\rho$, which governs the shape of the
overall momentum spectrum, and $\delta$, which governs the momentum dependence
of the parity-violating decay asymmetry. This analysis gives the results
$\rho=0.75014\pm 0.00017(\text{stat})\pm 0.00044(\text{syst})\pm
0.00011(\eta)$, where the last uncertainty arises from the correlation between
$\rho$ and the decay parameter $\eta$, and $\delta = 0.75067\pm
0.00030(\text{stat})\pm 0.00067(\text{syst})$. These are consistent with the
value of 3/4 given for both parameters in the Standard Model of particle
physics, and are a factor of two more precise than the measurements previously
published by TWIST. A new global analysis of all available muon decay data
incorporating these results is presented. Improved lower and upper limits on
the decay parameter $P_\mu^\pi\xi$ of $0.99524 < P_\mu^\pi\xi \leq \xi <
1.00091$ at 90% confidence are determined, where $P_\mu^\pi$ is the
polarization of the muon when it is created during pion decay, and $\xi$
governs the muon decay asymmetry. These results set new model-independent
constraints on the possible weak interactions of right-handed particles.
Specific implications for left-right symmetric models are discussed.


title: Z' boson detection in the Minimal Quiver Standard Model

abstract:
  We undertake a phenomenological study of the extra neutral Z' boson in the
Minimal Quiver Standard Model and discuss limits on the model's parameters from
previous precision electroweak experiments, as well as detection prospects at
the Large Hadron Collider at CERN. We find that masses lower than around 700
GeV are excluded by the $Z$-pole data from the CERN-LEP collider, and below 620
GeV by experimental data from di-electron events at the Fermilab-Tevatron
collider. We also find that at a mass of 1 TeV the LHC cross section would show
a small peak in the di-lepton and top pair channel.


title:
Specificity of Phase Transition of Quasi-Spin System in Two-Quantum
  Exchange with Thermostat

abstract:
  The quantum phase transition of the system of N radiators in case of
two-photon exchange interaction with cavity electromagnetic field is
considered. It is shown that for this system the atom-field exchange integral
increases with the increase of temperature. This effect generates peculiarities
in phase transition picture. The process of nonlinear exchange between the
quasi-spins leads to the increase of critical temperature as compared to
traditional second order phase transition of quasi-spin system.


title:
Gauge symmetry breaking and topological quantization for the Pauli
  Hamiltonian

abstract:
  We discuss the Pauli Hamiltonian within a ${SU(2)}$ gauge theory
interpretation, where the gauge symmetry is broken. This interpretation carries
directly over to the structural inversion asymmetric spin-orbit interactions in
semiconductors and offers new insight into the problem of spin currents in the
condensed matter environment. The central results is that symmetry breaking
leads to zero spin conductivity in contrast to predictions of Gauge symmetric
treatments. Computing the translation operator commutation relations comprising
the simplest possible structural inversion asymmetry due to an external
electric field, we derive a new condition for orbit quantization. The relation
between the topological nature of this effect is consistent with our
non-Abelian gauge symmetry breaking scenario.


title:
The Magellanic Cloud Calibration of the Galactic Planetary Nebula
  Distance Scale

abstract:
  Galactic planetary nebula (PN) distances are derived, except in a small
number of cases, through the calibration of statistical properties of PNe. Such
calibrations are limited by the accuracy of individual PN distances which are
obtained with several non-homogeneous methods, each carrying its own set of
liabilities. In this paper we use the physical properties of the PNe in the
Magellanic Clouds, and their accurately known distances, to recalibrate the
Shklovsky/Daub distance technique. Our new calibration is very similar (within
1 percent) of the commonly used distance scale by Cahn et al. (1992), although
there are important differences. We find that neither distance scale works well
for PNe with classic ("butterfly") bipolar morphology, and while the radiation
bounded PN sequences in both the Galactic and the Magellanic Cloud calibration
have similar slopes, the transition from optically thick to optically thin
appears to occur at higher surface brightness and smaller size than that
adopted by Cahn et al. The dispersion in the determination of the scale factor
suggests that PN distances derived by this method are uncertain by at least 30
percent, and that this dispersion cannot be reduced significantly by using
better calibrators. We present a catalog of Galactic PN distances using our
re-calibration which can be used for future applications, and compare the best
individual Galactic PN distances to our new and several other distance scales,
both in the literature and newly recalibrated by us, finding that our scale is
the most reliable to date.


title:
X-ray observations of the galaxy cluster PKS 0745-191: To the virial
  radius, and beyond

abstract:
  We measure X-ray emission from the outskirts of the cluster of galaxies PKS
0745-191 with Suzaku, determining radial profiles of density, temperature,
entropy, gas fraction, and mass. These measurements extend beyond the virial
radius for the first time, providing new information about cluster assembly and
the diffuse intracluster medium out to ~1.5 r_200, (r_200 ~ 1.7 Mpc ~ 15'). The
temperature is found to decrease by roughly 70 per cent from 0.3-1 r_200. We
also see a flattening of the entropy profile near the virial radius and
consider the implications this has for the assumption of hydrostatic
equilibrium when deriving mass estimates. We place these observations in the
context of simulations and analytical models to develop a better understanding
of non-gravitational physics in the outskirts of the cluster.


title: Generalization of the Apollonius Circles

abstract:
  The three Apollonius circles of a triangle, each passing through a triangle
vertex, the corresponding vertex of the cevian triangle of the incenter and the
corresponding vertex of the circumcevian triangle of the symmedian point, are
coaxal. Similarly defined three circles remain coaxal, when the circumcevian
triangle is defined with respect to any point on the triangle circumconic
through the incenter and symmedian point. Inversion in the incircle of the
reference triangle carries these three coaxal circles into coaxal circles, each
passing through a vertex of the inverted triangle and centered on the opposite
sideline, at the intersection of the orthotransversal with respect to a point
on the Euler line of the inverted triangle. A similar circumconic exists in a
more general configuration, when the cevian triangle is defined with respect to
an arbitrary point, passing through this arbitrary point and isogonal conjugate
of its complement.


title:
On Energy Distribution of Two Space-times with Planar and Cylindrical
  Symmetries

abstract:
  Considering encouraging Virbhadra's results about energy distribution of
non-static spherically symmetric metrics in Kerr-Schild class, it would be
interesting to study some space-times with other symmetries. Using different
energy-momentum complexes, i.e. M{\o}ller, Einstein, and Tolman, in static
plane-symmetric and cylindrically symmetric solutions of Einstein-Maxwell
equations in 3+1 dimensions, energy (due to matter and fields including
gravity) distribution is studied. Energy expressions are obtained finite and
well-defined. calculations show interesting coincidences between the results
obtained by Einstein and Tolamn prescriptions. Our results support the
Cooperstock hypothesis about localized energy.


title:
Boole's formula as a consequence of Lagrange's Interpolating Polynomial
  theorem

abstract:
  We present a slightly more general version of Boole's additive formula for
factorials as a simple consequence of Lagrange's Interpolating Polynomial
theorem.


title:
Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3
  Solar Mass Main Sequence Stars

abstract:
  We describe calculations for the formation of icy planets and debris disks at
30-150 AU around 1-3 solar mass stars. Debris disk formation coincides with the
formation of planetary systems. As protoplanets grow, they stir leftover
planetesimals to large velocities. A cascade of collisions then grinds the
leftovers to dust, forming an observable debris disk. Stellar lifetimes and the
collisional cascade limit the growth of protoplanets. The maximum radius of icy
planets, roughly 1750 km, is remarkably independent of initial disk mass,
stellar mass, and stellar age. These objects contain no more than 3% to 4% of
the initial mass in solid material. Collisional cascades produce debris disks
with maximum luminosity of roughly 0.002 times the stellar luminosity. The peak
24 micron excess varies from roughly 1% of the stellar photospheric flux for 1
solar mass stars to roughly 50 times the stellar photospheric flux for 3 solar
mass stars. The peak 70-850 micron excesses are roughly 30-100 times the
stellar photospheric flux. For all stars, the 24-160 micron excesses rise at
stellar ages of 5-20 Myr, peak at 10-50 Myr, and then decline. The decline is
roughly a power law, with f propto t^{-n} and n = 0.6-1.0. This predicted
evolution agrees with published observations of A-type and solar-type stars.
The observed far-IR color evolution of A-type stars also matches model
predictions.


title: Cohomology of normic systems and fake Z_p extensions

abstract:
  We set up a general framework to study Tate cohomology groups of Galois
modules along $\mathbb{Z}_p$-extensions of number fields. Under suitable
assumptions on the Galois modules, we establish the existence of a five-term
exact sequence in a certain quotient category whose objects are simultaneously
direct and inverse systems, subject to some compatibility. The exact sequence
allows one, in particular, to control the behaviour of the Tate cohomology
groups of the units along $\mathbb{Z}_p$-extensions. As an application, we
study the growth of class numbers along what we call "fake
$\mathbb{Z}_p$-extensions of dihedral type". This study relies on a previous
work, where we established a class number formula for dihedral extensions in
terms of the cohomology groups of the units.


title:
Coherent structures in Dissipative Particle Dynamics simulations of the
  transition to turbulence in compressible shear flows

abstract:
  We present simulations of coherent structures in compressible flows near the
transition to turbulence using the Dissipative Particle Dynamics (DPD) method.
The structures we find are remarkably consistent with experimental observations
and DNS simulations of incompressible flows, despite a difference in Mach
number of several orders of magnitude. The bifurcation from the laminar flow is
bistable and shifts to higher Reynolds numbers when the fluid becomes more
compressible. This work underlines the robustness of coherent structures in the
transition to turbulence and illustrates the ability of particle-based methods
to reproduce complex non-linear instabilities.


title:
Polariton Lasing in a Multilevel Quantum Dot Strongly Coupled To a
  Single Photon Mode

abstract:
  We present an approximate analytic expression for the photoluminescence
spectral function of a model polariton system, which describes a quantum dot,
with a finite number of fermionic levels, strongly interacting with the lowest
photon mode of a pillar microcavity. Energy eigenvalues and wavefunctions of
the electron-hole-photon system are obtained by numerically diagonalizing the
Hamiltonian. Pumping and photon losses through the cavity mirrors are described
with a master equation, which is solved in order to determine the stationary
density matrix. The photon first-order correlation function, from which the
spectral function is found, is computed with the help of the Quantum Regression
Theorem. The spectral function qualitatively describes the polariton lasing
regime in the model, corresponding to pumping rates two orders of magnitude
lower than those needed for ordinary (photon) lasing. The second-order
coherence functions for the photon and the electron-hole subsystems are
computed as functions of the pumping rate.


title: Spectral Analysis of Gluonic Pole Matrix Elements

abstract:
  We use a spectator framework to investigate the spectral properties of
quark-quark-gluon correlators and use this to study gluonic pole matrix
elements. Such matrix elements appear in principle both for distribution
functions such as the Sivers function and fragmentation functions such as the
Collins function. We find that the contribution of the gluonic pole matrix
element in fragmentation functions vanishes. This outcome is important in the
study of universality for fragmentation functions.


title: Algorithms for Secretary Problems on Graphs and Hypergraphs

abstract:
  We examine several online matching problems, with applications to Internet
advertising reservation systems. Consider an edge-weighted bipartite graph G,
with partite sets L, R. We develop an 8-competitive algorithm for the following
secretary problem: Initially given R, and the size of L, the algorithm receives
the vertices of L sequentially, in a random order. When a vertex l \in L is
seen, all edges incident to l are revealed, together with their weights. The
algorithm must immediately either match l to an available vertex of R, or
decide that l will remain unmatched.
  Dimitrov and Plaxton show a 16-competitive algorithm for the transversal
matroid secretary problem, which is the special case with weights on vertices,
not edges. (Equivalently, one may assume that for each l \in L, the weights on
all edges incident to l are identical.) We use a similar algorithm, but
simplify and improve the analysis to obtain a better competitive ratio for the
more general problem. Perhaps of more interest is the fact that our analysis is
easily extended to obtain competitive algorithms for similar problems, such as
to find disjoint sets of edges in hypergraphs where edges arrive online. We
also introduce secretary problems with adversarially chosen groups. Finally, we
give a 2e-competitive algorithm for the secretary problem on graphic matroids,
where, with edges appearing online, the goal is to find a maximum-weight
acyclic subgraph of a given graph.


title:
Dispersing bimagnons and doping induced bimagnon-charge modes in
  superconducting cuprates

abstract:
  In the early days of high temperature superconductivity it was already
recognized that magnetic properties of these materials are intimately related
to the superconducting ones . When doped, the long-range ordered
antiferromagnetic background of pristine copper-oxide insulators melts away and
makes room for a spin liquid and superconductivity. By resonant inelastic x-ray
scattering (RIXS) in the soft regime we probe the hitherto inaccessible
dynamical multiple-spin correlations of the magnetic background in a series of
parent compounds and in high Tc materials [NCCO (Nd2-xCexCuO4) and LSCO
(La2-xSrxCuO4)]. High resolution measurements allows the clear observation of
dispersing bimagnon excitations. In the undoped compounds the theory, fits the
data on these coherent spin excitations without free parameters. In nearly
optimally doped LSCO we observe the appearance of a new collective excitation
at an energy of 250 +/- 60 meV having the signature of a coupled
bimagnon-charge mode. It has a strongly reduced dispersion and lies in a so far
unexplored region of momentum and energy space in the mid-infrared.


title: The coarse classification of countable abelian groups

abstract:
  We prove that two countable locally finite-by-abelian groups G,H endowed with
proper left-invariant metrics are coarsely equivalent if and only if their
asymptotic dimensions coincide and the groups are either both
finitely-generated or both are infinitely generated. On the other hand, we show
that each countable group G that coarsely embeds into a countable abelian group
is locally nilpotent-by-finite. Moreover, the group G is locally
abelian-by-finite if and only if G is undistorted in the sense that G can be
written as the union of countably many finitely generated subgroups G_n such
that each G_n is undistorted in G_{n+1} (which means that the identity
inclusion from G_n to G_{n+1} is a quasi-isometric embedding with respect to
word metrics).


title: Test elements, retracts and automorphic orbits

abstract:
  Let $A_2$ be a free associative or polynomial algebra of rank two over a
field $K$ of characteristic zero. Based on the degree estimate of Makar-Limanov
and J.-T.Yu, we prove: 1) An element $p \in A_2$ is a test element if $p$ does
not belong to any proper retract of $A_2$; 2) Every endomorphism preserving the
automorphic orbit of a nonconstant element of $A_2$ is an automorphism.


title:
Cyclotron Modeling Phase-Resolved Infrared Spectroscopy of Polars III:
  AM Herculis and ST Leo Minoris

abstract:
  We present phase-resolved low resolution infrared spectra of AM Her and ST
LMi, two low-field polars that we observed with SPEX on the IRTF. Optical/NIR
lightcurves are also published to help constrain the viewing geometry and
brightness of the objects at the time they were observed. Currently, only
limited IR spectra have been published for these objects, and none with the
phase-coverage presented here. In both cases, the resulting spectra are
dominated by emission from the secondary star in the NIR. However, the emission
regions are also self-eclipsed, allowing us to isolate the cyclotron emission
through subtraction of the dim-phase spectrum. We use a ``Constant Lambda''
prescription to model the changing cyclotron features seen in the resulting
data. For AM Her, we find a best fit model of: B = 13.6 MG, kT = 4.0 keV, and
logLambda = 5.0. The cyclotron derived accretion geometry is consistent with an
orbital inclination of 50 degrees and a magnetic co-latitude of 85 degrees. For
ST LMi, B = 12.1 MG, kT = 3.3 keV, and logLambda = 5.7 with an orbital
inclination of 55 degrees and a magnetic co-latitude of 128 degrees.


title: Controlling entanglement by direct quantum feedback

abstract:
  We discuss the generation of entanglement between electronic states of two
atoms in a cavity using direct quantum feedback schemes. We compare the effects
of different control Hamiltonians and detection processes in the performance of
entanglement production and show that the quantum-jump-based feedback proposed
by us in Phys. Rev. A {\bf 76} 010301(R) (2007) can protect highly entangled
states against decoherence. We provide analytical results that explain the
robustness of jump feedback, and also analyse the perspectives of experimental
implementation by scrutinising the effects of imperfections and approximations
in our model.


title:
On spatial volume averaging in Lema\^{\i}tre--Tolman--Bondi dust models.
  Part I: back reaction, spacial curvature and binding energy

abstract:
  We provide a comprehensive analytic study (rigorous and qualitative) of the
conditions for the existence of a a positive kinematic back reaction term
$\QQ>0$, in the context of Buchert's scalar averaging formalism applied to
spherically symmetric Lema\^itre-Tolman-Bondi (LTB) dust solutions in which
averaging domains are given as spherical comoving regions containing a symmetry
center. We introduce proper volume and quasi-local average functionals and
functions in order to examine the conditions for $\QQ\geq 0$, and in the
process we also explore the relation between back reaction, spatial curvature
and binding energy for a wide variety of LTB configurations. The back reaction
term is positive for all "hyperbolic" regular domains with negative spatial
curvature, either in the full radial range or in the radial asymptotic range.
This result is also valid if these domains contain an inner "elliptic" region
with positive curvature undergoing local collapse. For some cases in which
positive spatial curvature decreases asymptotically, the conditions for a
positive back reaction can still be met but seem to be more restrictive. Since
$\QQ>0$ is a necessary condition for a positive "effective" acceleration that
would mimic the effect of dark energy (in the context of Buchert's formalism),
we examine this issue in LTB models in a follow up paper (part II).


title: Static and dynamical properties of elliptic quantum corrals

abstract:
  Due to their focalizing properties, elliptic quantum corrals present very
interesting physical behaviors. In this work, we analyze static and dynamical
properties of these systems. Results are presented for realistic values of the
parameters, which might be useful for comparison with experiments. We study
noninteracting corrals and their response to several kinds of external
perturbations, observing that, for realistic values of the Fermi level, the
dynamics involves only a few number of excited states, making the system quite
robust with respect to possible sources of decoherence. We also study the
system in the presence of two S=1/2 impurities located at its foci, which
interact with the electrons of the ellipse via a superexchange interaction J.
This system is diagonalized numerically and properties such as the spin gap and
spin-spin static and dynamical correlations are studied. We find that, for
small J, both spins are locked in a singlet or triplet state, for even or odd
filling, respectively, and its spin dynamics consists mainly of a single peak
above the spin gap. In this limit, we can define an effective Heisenberg
Hamiltonian to describe the low-energy properties. For larger J, more states
are involved and the localized spins decorrelate in a manner similar to the
Ruderman-Kittel-Kasuya-Yosida-Kondo transition for the two-impurity problem.


title:
Exciton effects in optical absorption spectra of boron-nitride (BN)
  nanotubes

abstract:
  Exciton effects are studied in single-wall boron-nitride nanotubes. The
Coulomb interaction dependence of the band gap, the optical gap, and the
binding energy of excitons are discussed. The optical gap of the (5,0) nanotube
is about 6eV at the onsite interaction U=2t with the hopping integral t=1.1eV.
The binding energy of the exciton is 0.50eV for these parameters. This energy
agrees well with that of other theoretical investigations. We find that the
energy gap and the binding energy are almost independent of the geometries of
nanotubes. This novel property is in contrast with that of the carbon nanotubes
which show metallic and semiconducting properties depending on the chiralities.


title: A characterization of quiver algebras based on double derivations

abstract:
  Let k a characteristic zero field. We give a characterization for the finite
quiver k-algebras, based on double derivations. More precisely, we prove that
if an associative and unitary k-algebra have a family of double derivations
satisfying suitable conditions, then it is (canonically isomorphic to) a quiver
algebra. This is the non-commutative version of a result of D. Wright.


title: Canonical Hamiltonians for waves in inhomogeneous media

abstract:
  We obtain a canonical form of a quadratic Hamiltonian for linear waves in a
weakly inhomogeneous medium. This is achieved by using the WKB representation
of wave packets. The canonical form of the Hamiltonian is obtained via the
series of canonical Bogolyubov-type and near-identical transformations. Various
examples of the application illustrating the main features of our approach are
presented. The knowledge of the Hamiltonian structure for linear wave systems
provides a basis for developing a theory of weakly nonlinear random waves in
inhomogeneous media generalizing the theory of homogeneous wave turbulence.


title: Self-forces from generalized Killing fields

abstract:
  A non-perturbative formalism is developed that simplifies the understanding
of self-forces and self-torques acting on extended scalar charges in curved
spacetimes. Laws of motion are locally derived using momenta generated by a set
of generalized Killing fields. Self-interactions that may be interpreted as
arising from the details of a body's internal structure are shown to have very
simple geometric and physical interpretations. Certain modifications to the
usual definition for a center-of-mass are identified that significantly
simplify the motions of charges with strong self-fields. A derivation is also
provided for a generalized form of the Detweiler-Whiting axiom that pointlike
charges should react only to the so-called regular component of their
self-field. Standard results are shown to be recovered for sufficiently small
charge distributions.


title:
Non-Gaussianity test for discriminating gravitational wave backgrounds
  around 0.1-1Hz

abstract:
  We propose a non-Gaussianity test for gravitational wave backgrounds by
combining data streams of multiple detectors. This simple method allows us to
check whether a detected background is "smooth" enough to be consistent with an
inflation-type background, or is contaminated by individually undetectable weak
burst signals. The proposed test would be quite useful for the Big Bang
Observer or DECIGO whose primary target is a background from inflation at
0.1-1Hz where gravitational wave bursts from supernovae of population III stars
might become a troublesome foreground.


title: The Grothendieck-Katz Conjecture for certain locally symmetric varieties

abstract:
  Using Margulis's results on lattices in semisimple Lie groups, we prove the
Grothendieck-Katz $p$-Curvature Conjecture for certain locally symmetric
varieties, including the moduli space of abelian varieties ${\cal A}_g$ when $g
> 1.$


title:
CSI: A Paradigm for Behavior-oriented Delivery Services in Mobile Human
  Networks

abstract:
  We propose behavior-oriented services as a new paradigm of communication in
mobile human networks. Our study is motivated by the tight user-network
coupling in future mobile societies. In such a paradigm, messages are sent to
inferred behavioral profiles, instead of explicit IDs. Our paper provides a
systematic framework in providing such services. First, user behavioral
profiles are constructed based on traces collected from two large wireless
networks, and their spatio-temporal stability is analyzed. The implicit
relationship discovered between mobile users could be utilized to provide a
service for message delivery and discovery in various network environments. As
an example application, we provide a detailed design of such a service in
challenged opportunistic network architecture, named CSI. We provide a fully
distributed solution using behavioral profile space gradients and small world
structures.
  Our analysis shows that user behavioral profiles are surprisingly stable,
i.e., the similarity of the behavioral profile of a user to its future
behavioral profile is above 0.8 for two days and 0.75 for one week, and remains
above 0.6 for five weeks. The correlation coefficient of the similarity metrics
between a user pair at different time instants is above 0.7 for four days, 0.62
for a week, and remains above 0.5 for two weeks. Leveraging such a stability in
user behaviors, the CSI service achieves delivery rate very close to the
delay-optimal strategy (above 94%), with minimal overhead (less than 84% of the
optimal). We believe that this new paradigm will act as an enabler of multiple
new services in mobile societies, and is potentially applicable in
server-based, heterogeneous or infrastructure-less wireless environments.


title:
Generalized transverse momentum dependent parton distributions of the
  nucleon

abstract:
  We present first results from our analysis of the most general quark-quark
correlator of the nucleon, which can be parameterized in terms of so-called
generalized transverse momentum dependent parton distributions. These results
include the first complete parameterization of the nucleon GPDs and TMDs to all
twists as well as new results on possible nontrivial relations between them.


title:
Constraining the quasar population with the broad-line width
  distribution

abstract:
  We measure the width of the MgII $\lambda2799$ line in quasar spectra from
the SDSS, 2QZ and 2SLAQ surveys and, by invoking an unnormalised virial mass
estimator, relate the scatter in line width to the scatter in mass in the
underlying black hole population. We find conclusive evidence for a trend such
that there is less scatter in line width, and hence black hole mass, in more
luminous objects.
  However, the most luminous objects in our sample show such a low degree of
scatter in line width that, when combined with measures for the intrinsic
scatter in the radius-luminosity relation for the broad-line region in active
galaxies, an inconsistency arises in the virial technique for estimating black
hole masses. This analysis implies that, at least for the most luminous
quasars, either there is little-to-no intrinsic scatter in the
radius-luminosity relation or the MgII broad emission line region is not
totally dominated by virial velocities.
  Finally we exploit the measured scatter in line widths to constrain models
for the velocity field of the broad-line region. We show that the lack of
scatter in broad line-widths for luminous quasars is inconsistent with a pure
planar/disk-like geometry for the broad-line region... (abridged)


title:
General disagreement between the Geometrical Description of Dynamical
  In-stability -using non affine parameterizations- and traditional Tangent
  Dynamics

abstract:
  In this paper, the general disagreement of the geometrical lyapunov exponent
with lyapunov exponent from tangent dynamics is addressed. It is shown in a
quite general way that the vector field of geodesic spread $\xi^k_G$ is not
equivalent to the tangent dynamics vector $\xi^k_T$ if the parameterization is
not affine and that results regarding dynamical stability obtained in the
geometrical framework can differ qualitatively from those in the tangent
dynamics. It is also proved in a general way that in the case of Jacobi metric
-frequently used non affine parameterization-, $\xi^k_G$ satisfies differential
equations which differ from the equations of the tangent dynamics in terms that
produce parametric resonance, therefore, positive exponents for systems in
stable regimes.


title: Disorder Effects in the Quantum Hall Effect of Graphene p-n Junctions

abstract:
  The quantum Hall effect in graphene p-n junctions is studied numerically with
emphasis on the effect of disorder at the interface of two adjacent regions.
Conductance plateaus are found to be attached to the intensity of the disorder,
and are accompanied by universal conductance fluctuations in the bipolar
regime, which is in good agreement with theoretical predictions of the random
matrix theory on quantum chaotic cavities. The calculated Fano factors can be
used in an experimental identification of the underlying transport character.


title:
Path Gain Algebraic Formulation for the Scalar Linear Network Coding
  Problem

abstract:
  In the algebraic view, the solution to a network coding problem is seen as a
variety specified by a system of polynomial equations typically derived by
using edge-to-edge gains as variables. The output from each sink is equated to
its demand to obtain polynomial equations. In this work, we propose a method to
derive the polynomial equations using source-to-sink path gains as the
variables. In the path gain formulation, we show that linear and quadratic
equations suffice; therefore, network coding becomes equivalent to a system of
polynomial equations of maximum degree 2. We present algorithms for generating
the equations in the path gains and for converting path gain solutions to
edge-to-edge gain solutions. Because of the low degree, simplification is
readily possible for the system of equations obtained using path gains. Using
small-sized network coding problems, we show that the path gain approach
results in simpler equations and determines solvability of the problem in
certain cases. On a larger network (with 87 nodes and 161 edges), we show how
the path gain approach continues to provide deterministic solutions to some
network coding problems.


title: Relationship between granularity of antiferromagnet and exchange bias

abstract:
  We studied exchange bias in magnetic multilayers incorporating
antiferromagent CoO doped with up to 35 atomic percent of Pt. The exchange bias
increased with doping in epitaxial films, but did not significantly change in
polycrystalline films at the lowest measured temperature of 5 K, and decreased
at higher temperatures. We explain our results by the increased granularity of
the doped antiferromagnetic films, resulting in simultaneous enhancement of the
uncompensated spin density and reduction of the magnetic stability of
antiferromagnetic grains.


title:
Session Initiation Protocol (SIP) Server Overload Control: Design and
  Evaluation

abstract:
  A Session Initiation Protocol (SIP) server may be overloaded by
emergency-induced call volume, ``American Idol'' style flash crowd effects or
denial of service attacks. The SIP server overload problem is interesting
especially because the costs of serving or rejecting a SIP session can be
similar. For this reason, the built-in SIP overload control mechanism based on
generating rejection messages cannot prevent the server from entering
congestion collapse under heavy load. The SIP overload problem calls for a
pushback control solution in which the potentially overloaded receiving server
may notify its upstream sending servers to have them send only the amount of
load within the receiving server's processing capacity. The pushback framework
can be achieved by either a rate-based feedback or a window-based feedback. The
centerpiece of the feedback mechanism is the algorithm used to generate load
regulation information. We propose three new window-based feedback algorithms
and evaluate them together with two existing rate-based feedback algorithms. We
compare the different algorithms in terms of the number of tuning parameters
and performance under both steady and variable load. Furthermore, we identify
two categories of fairness requirements for SIP overload control, namely,
user-centric and provider-centric fairness. With the introduction of a new
double-feed SIP overload control architecture, we show how the algorithms can
meet those fairness criteria.


title:
Formation of a giant HI bridge between M31 and M33 from their tidal
  interaction

abstract:
  Recent observations have discovered a giant HI bridge that appears to connect
between the outer halo regions of M31 and M33. We propose that this HI bridge
can be formed as a result of the past interaction between M31 and M33 based on
test particle simulations with different orbits of M31 and M33 for the last ~ 9
Gyr. We show that strong tidal interaction between M31 and M33 about 4-8 Gyr
ago can strip HI gas from M33 to form HI streams around M31 which can be
observed as a HI bridge if they are projected onto the sky. We show that the
number fraction of models reproducing well the observed HI distribution of the
bridge is only ~0.01% (i.e., ~10 among ~10^5 models) and thus suggest that the
observed structure and kinematics of the HI bridge can give some constraints on
the past orbits of M31 and M33. We suggest that the observed outer HI warp in
M33 could be fossil evidence for the past M31-M33 interaction. We also suggest
that some of high velocity clouds (HVCs) recently found in M31 could be HI gas
originating from M33. We briefly discuss other possible scenarios for the
formation of the HI bridge.


title: Measurement and Evaluation of ENUM Server Performance

abstract:
  ENUM is a DNS-based protocol standard for mapping E.164 telephone numbers to
Internet Uniform Resource Identifiers (URIs). It places unique requirements on
the existing DNS infrastructure, such as data scalability, query throughput,
response time, and database update rates. This paper measures and evaluates the
performance of existing name server implementation as ENUM servers. We compared
PowerDNS (PDNS), BIND and Navitas. Results show that BIND is not suitable for
ENUM due to its poor scaling property. Both PDNS and Navitas can serve ENUM.
However, Navitas turns out to be highly optimized and clearly outperforms PDNS
in all aspects we have tested. We also instrumented the PDNS server to identify
its performance bottleneck and investigated ways to improve it.


title: Semiclassical spin liquid state of easy axis Kagome antiferromagnets

abstract:
  Motivated by recent experiments on Nd-langasite, we consider the effect of
strong easy axis single-ion anisotropy $D$ on $S > 3/2$ spins interacting with
antiferromagnetic exchange $J$ on the Kagome lattice. When $T \ll DS^2$, the
collinear low energy states selected by the anisotropy map on to configurations
of the classical Kagome lattice Ising antiferromagnet. However, the low
temperature limit is quite different from the cooperative Ising paramagnet that
obtains classically for $T \ll JS^2$. We find that sub-leading ${\mathcal
O}(J^3S/D^2)$ multi-spin interactions arising from the transverse quantum
dynamics result in a crossover from an intermediate temperature classical
cooperative Ising paramagnet to a semiclassical spin liquid with distinct
short-ranged correlations for $T \ll J^3S/D^2$.


title:
A microscopic description of light induced defects in amorphous silicon
  solar cells

abstract:
  Using a combination of quantum and classical computational approaches, we
model the electronic structure in amorphous silicon in order gain understanding
of the microscopic atomic configurations responsible for light induced
degradation of solar cells. We demonstrate that regions of strained silicon
bonds could be as important as dangling bonds for creating traps for charge
carriers. Further, our results show that defects are preferentially formed when
a region in the amorphous silicon contains a hole and a light-induced
excitation. These results agree with the puzzling dependencies on temperature,
time, and pressure observed experimentally.


title: Timed Parity Games: Complexity and Robustness

abstract:
  We consider two-player games played in real time on game structures with
clocks and parity objectives. The games are concurrent in that at each turn,
both players independently propose a time delay and an action, and the action
with the shorter delay is chosen. To prevent a player from winning by blocking
time, we restrict each player to strategies that ensure that the player cannot
be responsible for causing a zeno run. First, we present an efficient reduction
of these games to turn-based (i.e., nonconcurrent) finite-state (i.e., untimed)
parity games. The states of the resulting game are pairs of clock regions of
the original game. Our reduction improves the best known complexity for solving
timed parity games. Moreover, the rich class of algorithms for classical parity
games can now be applied to timed parity games.
  Second, we consider two restricted classes of strategies for the player that
represents the controller in a real-time synthesis problem, namely,
limit-robust and bounded-robust strategies. Using a limit-robust strategy, the
controller cannot choose an exact real-valued time delay but must allow for
some nonzero jitter in each of its actions. If there is a given lower bound on
the jitter, then the strategy is bounded-robust. We show that exact strategies
are more powerful than limit-robust strategies, which are more powerful than
bounded-robust strategies for any bound. For both kinds of robust strategies,
we present efficient reductions to standard timed automaton games. These
reductions provide algorithms for the synthesis of robust real-time
controllers.


title:
Interaction-induced first order correlation between spatially-separated
  1D dipolar fermions

abstract:
  We calculate the ground-state properties of fermionic dipolar atoms or
molecules in a one-dimensional double-tube potential by using the Luttinger
liquid theory and the density matrix renormalization-group calculation. When
the external field is applied near a magic angle with respect to the
double-tube plane, the long-ranged dipolar interaction can generate a
spontaneous correlation between fermions in different tubes, even when the bare
intertube tunneling rate is negligibly small. Such interaction-induced
correlation strongly enhances the contrast of the interference fringes and
therefore can be easily observed in the standard time-of-flight experiment.


title: AdS/QCD and Type 0 String Theory

abstract:
  We study gauge/string duality with flavor degrees of freedom in type 0B
string theory. We construct a model by placing the N_f probe D9_-/anti-D9_-
brane pairs in the background of the N_c electric D3-branes. This model has
some features in common with QCD, as in AdS/QCD model. By analyzing the
effective action, we obtain the linear confinement behavior for the masses of
the highly excited spin-1 mesons.


title:
Possibility of Unconventional Pairing Due to Coulomb Interaction in
  Fe-Based Pnictide Superconductors: Perturbative Analysis of Multi-Band
  Hubbard Models

abstract:
  Possibility of unconventional pairing due to Coulomb interaction in
iron-pnictide superconductors is studied by applying a perturbative approach to
realistic 2- and 5-band Hubbard models. The linearized Eliashberg equation is
solved by expanding the effective pairing interaction perturbatively up to
third order in the on-site Coulomb integrals. The numerical results for the
5-band model suggest that the eigenvalues of the Eliashberg equation are
sufficiently large to explain the actual high Tc for realistic values of
Coulomb interaction and the most probable pairing state is spin-singlet s-wave
without any nodes just on the Fermi surfaces, although the superconducting
order parameter changes its sign between the small Fermi pockets. On the other
hand the 2-band model is quite insufficient to explain the actual high Tc.


title:
A VoIP Privacy Mechanism and its Application in VoIP Peering for Voice
  Service Provider Topology and Identity Hiding

abstract:
  Voice Service Providers (VSPs) participating in VoIP peering frequently want
to withhold their identity and related privacy-sensitive information from other
parties during the VoIP communication. A number of existing documents on VoIP
privacy exist, but most of them focus on end user privacy. By summarizing and
extending existing work, we present a unified privacy mechanism for both VoIP
users and service providers. We also show a case study on how VSPs can use this
mechanism for identity and topology hiding in VoIP peering.


title:
The Chow group of zero-cycles on certain Ch{\^a}telet surfaces over
  local fields

abstract:
  We compute the Chow group of zero-cycles on certain Ch{\^a}telet surfaces
over local fields.


title:
Form Factors of $B_{u,d,s}$ Decays into P-Wave Axial-Vector Mesons in
  the Light-Cone Sum Rule Approach

abstract:
  We calculate the vector and axial-vector form factors of $B_{u,d,s}$ decays
into P-wave axial-vector mesons in the light-cone sum rule approach. For the
sum rule results, we have included corrections of order $m_A/m_b$, where $m_A$
is the mass of the axial-vector meson $A$. The results are relevant to the
light-cone distribution amplitudes of the axial-vector mesons. It is important
to note that, owing to the $G$-parity, the chiral-even two-parton light-cone
distribution amplitudes of the $^3P_1$ ($^1P_1$) mesons are symmetric
(antisymmetric) under the exchange of quark and anti-quark momentum fractions
in the SU(3) limit. For chiral-odd light-cone distribution amplitudes, it is
the other way around. The predictions for decay rates of $B_{u,d,s} \to A e
\nu_e$ are also presented.


title:
Domain Wall and Periodic Solutions of Coupled phi6 and Coupled phi6-phi4
  Models

abstract:
  We obtain several higher order periodic solutions of a Coupled phi6 model in
terms of Lame polynomials of order one and two. These solutions are unusual in
the sense that while they are the solutions of the coupled problem, they are
not the solutions of the uncoupled problem. We also obtain exact solutions of
coupled phi6-phi4 models, both when the phi4 potential corresponds to a first
order (asymmetric double well) or a second order (symmetric double well)
transition.


title:
A Counterexample Guided Abstraction-Refinement Framework for Markov
  Decision Processes

abstract:
  The main challenge in using abstractions effectively, is to construct a
suitable abstraction for the system being verified. One approach that tries to
address this problem is that of {\it counterexample guided
abstraction-refinement (CEGAR)}, wherein one starts with a coarse abstraction
of the system, and progressively refines it, based on invalid counterexamples
seen in prior model checking runs, until either an abstraction proves the
correctness of the system or a valid counterexample is generated. While CEGAR
has been successfully used in verifying non-probabilistic systems
automatically, CEGAR has not been applied in the context of probabilistic
systems. The main issues that need to be tackled in order to extend the
approach to probabilistic systems is a suitable notion of ``counterexample'',
algorithms to generate counterexamples, check their validity, and then
automatically refine an abstraction based on an invalid counterexample. In this
paper, we address these issues, and present a CEGAR framework for Markov
Decision Processes.


title: Absolute norms of p-primary units

abstract:
  We prove a local analogue of a theorem of J. Martinet about the absolute norm
of the relative discriminant ideal of an extension of number fields. The result
can be seen as a statement about 2-primary units. We also prove a similar
statement about the absolute norms of p-primary units, for all primes p.


title:
Studies on phase transition and phase coexistence - traversing T and H
  using liquid helium

abstract:
  Liquid helium is crucial to conveniently vary magnetic field (H) and
temperature (T) giving access to a large region of (H, T) space; in stark
contrast with the effort currently required to explore a comparable region of
(P, T) space. The centenary of the liquefaction of helium is an appropriate
occasion to talk on the utilization of our facilities for studies across first
order phase transitions. We observed some interesting effects in variety of
systems traversing (H, T) space across the magnetic first order phase
transitions. We focus here on a few recent intriguing discoveries in the
half-doped manganites related to the coexistence of equilibrium phase, with a
glass-like phase having both structural and magnetic long-range order.


title:
Excitation energy dependence of electron-phonon interaction in ZnO
  nanoparticles

abstract:
  Raman spectroscopic investigations are carried out on ZnO nanoparticles for
various photon energies. Intensities of E1-LO and E2 modes exhibit large
changes as the excitation energy varied from 2.41 to 3.815 eV, signifying
substantially large contribution of Frohlich interaction to the Raman
polarizability as compared to deformation potential close to the resonance.
Relative strength of these two mechanisms is estimated for the first time in
nanoparticles and compared with those in the bulk.


title:
Magnetic vortices for a Ginzburg-Landau type energy with discontinuous
  constraint. II

abstract:
  We study vortex nucleation for minimizers of a Ginzburg-Landau energy with
discontinuous constraint. For applied magnetic fields comparable with the first
critical field of vortex nucleation, we determine the limiting vorticities.


title: Spacetime Encodings I- A Spacetime Reconstruction Problem

abstract:
  This paper explores features of an idealized mathematical machine (algorithm)
that would be capable of reconstructing the gravitational nature (the
multipolar structure or spacetime metric) of a compact object, by observing
gravitational radiation emitted by a small object that orbits and spirals into
it. An outline is given of the mathematical developments that must be carried
out in order to construct such a machine.


title: Spacetime Encodings II - Pictures of Integrability

abstract:
  I visually explore the features of geodesic orbits in arbitrary stationary
axisymmetric vacuum (SAV) spacetimes that are constructed from a complex Ernst
potential. Some of the geometric features of integrable and chaotic orbits are
highlighted. The geodesic problem for these SAV spacetimes is rewritten as a
two degree of freedom problem and the connection between current ideas in
dynamical systems and the study of two manifolds sought. The relationship
between the Hamilton-Jacobi equations, canonical transformations, constants of
motion and Killing tensors are commented on. Wherever possible I illustrate the
concepts by means of examples from general relativity. This investigation is
designed to build the readers' intuition about how integrability arises, and to
summarize some of the known facts about two degree of freedom systems. Evidence
is given, in the form of orbit-crossing structure, that geodesics in SAV
spacetimes might admit, a fourth constant of motion that is quartic in momentum
(by contrast with Kerr spacetime, where Carter's fourth constant is quadratic).


title:
Self-consistent simulations of star cluster formation from gas clouds
  under the influence of galaxy-scale tidal fields

abstract:
  We present the first results of a project aimed at following the formation
and long-term dynamical evolution of star clusters within the potential of a
host galaxy. Here we focus on a model evolved within a simplified potential
representing the Large Magellanic Cloud. This demonstrates for the first time
the self-consistent formation of a bound star cluster from a giant molecular
cloud. The model cluster reproduces the density profiles and structural
characteristics of observed star clusters.


title: On the moments of the Riemann zeta-function in short intervals

abstract:
  Assuming the Riemann Hypothesis it is proved that, for fixed $k>0$ and $H =
T^\theta$ with fixed $0<\theta \le 1$, $$ \int_T^{T+H}|\zeta(1/2+it)|^{2k} dt
\ll H(\log T)^{k^2(1+O(1/\log_3T))}, $$ where $\log_jT = \log(\log_{j-1}T)$.
The proof is based on the recent method of K. Soundararajan for counting the
occurrence of large values of $\log|\zeta(1/2+it)|$, who proved that $$
\int_0^{T}|\zeta(1/2+it)|^{2k} dt \ll_\epsilon T(\log T)^{k^2+\epsilon}. $$


title:
Random drift versus selection in academic vocabulary: an evolutionary
  analysis of published keywords

abstract:
  The evolution of vocabulary in academic publishing is characterized via
keyword frequencies recorded the ISI Web of Science citations database. In four
distinct case-studies, evolutionary analysis of keyword frequency change
through time is compared to a model of random copying used as the null
hypothesis, such that selection may be identified against it. The case studies
from the physical sciences indicate greater selection in keyword choice than in
the social sciences. Similar evolutionary analyses can be applied to a wide
range of phenomena; wherever the popularity of multiple items through time has
been recorded, as with web searches, or sales of popular music and books, for
example.


title: Multiple D2-Brane Action from M2-Branes

abstract:
  We study the detail derivation of the multiple D2-brane effective action from
multiple M2-branes in the Bagger-Lambert-Gustavsson (BLG) theory and the
Aharony-Bergman-Jafferis-Maldacena (ABJM) theory by employing the novel Higgs
mechanism. We show explicitly that the high-order F^3 and F^4 terms are
commutator terms, and conjecture that all the high-order terms are commutator
terms. Because the commutator terms can be treated as the covariant derivative
terms, these high-order terms do not contribute to the multiple D2-brane
effective action. Inspired by the derivation of a single D2-brane from a
M2-brane, we consider the curved M2-branes and introduce an auxiliary field.
Integrating out the auxiliary field, we indeed obtain the correct high-order
F^4 terms in the D2-brane effective action from the BLG theory and the ABJM
theory with SU(2)\times SU(2) gauge symmetry, but we can not obtain the correct
high-order F^4 terms from the ABJM theory with U(N)\times U(N) and SU(N)\times
SU(N) gauge symmetries for N > 2. We also briefly comment on the (gauged) BF
membrane theory.


title:
From rings to bulges: evidence for rapid secular galaxy evolution at z~2
  from integral field spectroscopy in the SINS survey

abstract:
  We present Ha integral field spectroscopy of well resolved, UV/optically
selected z~2 star-forming galaxies as part of the SINS survey with SINFONI on
the ESO VLT. Our laser guide star adaptive optics and good seeing data show the
presence of turbulent rotating star forming rings/disks, plus central
bulge/inner disk components, whose mass fractions relative to total dynamical
mass appears to scale with [NII]/Ha flux ratio and star formation age. We
propose that the buildup of the central disks and bulges of massive galaxies at
z~2 can be driven by the early secular evolution of gas-rich proto-disks. High
redshift disks exhibit large random motions. This turbulence may in part be
stirred up by the release of gravitational energy in the rapid cold accretion
flows along the filaments of the cosmic web. As a result dynamical friction and
viscous processes proceed on a time scale of <1 Gyr, at least an order of
magnitude faster than in z~0 disk galaxies. Early secular evolution thus drives
gas and stars into the central regions and can build up exponential disks and
massive bulges, even without major mergers. Secular evolution along with
increased efficiency of star formation at high surface densities may also help
to account for the short time scales of the stellar buildup observed in massive
galaxies at z~2.


title:
EIS/Hinode observations of Doppler flow seen through the 40 arcsec wide
  slit

abstract:
  The Extreme ultraviolet Imaging Spectrometer (EIS) on board Hinode is the
first solar telescope to obtain wide slit spectral images that can be used for
detecting Doppler flows in transition region and coronal lines on the Sun and
to relate them to their surrounding small scale dynamics. We select EIS lines
covering the temperature range 6x10^4 K to 2x10^6 K that give spectrally pure
images of the Sun with the 40 arcsec slit. In these images Doppler shifts are
seen as horizontal brightenings. Inside the image it is difficult to
distinguish shifts from horizontal structures but emission beyond the image
edge can be unambiguously identified as a line shift in several lines separated
from others on their blue or red side by more than the width of the
spectrometer slit (40 pixels). In the blue wing of He II, we find a large
number of events with properties (size and lifetime) similar to the
well-studied explosive events seen in the ultraviolet spectral range.
Comparison with X-Ray Telescope (XRT) images shows many Doppler shift events at
the footpoints of small X-ray loops. The most spectacular event observed showed
a strong blue shift in transition region and lower corona lines from a small
X-ray spot that lasted less than 7 min. The emission appears to be near a cool
coronal loop connecting an X-ray bright point to an adjacent region of quiet
Sun. The width of the emission implies a line-of-sight velocity of 220 km/s. In
addition, we show an example of an Fe XV shift with a velocity about 120 km/s,
coming from what looks like a narrow loop leg connecting a small X-ray
brightening to a larger region of X-ray emission.


title: Quantum gravity equation in large N Yang-Mills quantum mechanics

abstract:
  We propose a new interpretation of the BFSS large N matrix quantum mechanics
analogous to a novel interpretation of the IKKT matrix model where infinitely
large N matrices act as differential operators in a curved space. In this
picture, the Schr\"odinger equation in the BFSS model is regarded as the
Wheeler-DeWitt equation which determines the wave function of universe. An
explicit solution of wave function is studied in a simple two-dimensional
minisuperspace model.


title:
An essential relation between Einstein metrics, volume entropy, and
  exotic smooth structures

abstract:
  We show that the minimal volume entropy of closed manifolds remains
unaffected when nonessential manifolds are added in a connected sum. We combine
this result with the stable cohomotopy invariant of Bauer-Furuta in order to
present an infinite family of four-manifolds with the following properties:
  1) They have positive minimal volume entropy.
  2) They satisfy a strict version of the Gromov-Hitchin-Thorpe inequality,
with a minimal volume entropy term.
  3) They nevertheless admit infinitely many distinct smooth structures for
which no compatible Einstein metric exists.


title: A 4th generation scenario

abstract:
  A fourth generation could provide, within SUSY, a solution to baryogenesis at
the EW scale. It is allowed by precision measurements. Available data from
Tevatron already restrict the allowed domain of parameters for the new quarks
and the Higgs boson. There are some indications from b->s transitions which
could be interpreted within an extension of the CKM matrix to 4x4, in
particular CPV in the Bs time-dependence for the J/Psi-Phi mode observed at
Tevatron. If confirmed with more data the 4MSSM interpretation predicts a very
interesting scenario for LHC and a TeV LC.


title: Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

abstract:
  The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and
$pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$
400 MeV) using the short version of the COSY-TOF spectrometer. The central
calorimeter provided particle identification, energy determination and neutron
detection in addition to time-of-flight and angle measurements from other
detector parts. Thus all pion production channels were recorded with 1-4
overconstraints. Main emphasis is put on the presentation and discussion of the
$np\pi^+$ channel, since the results on the other channels have already been
published previously. The total and differential cross sections obtained are
compared to theoretical calculations. In contrast to the $pp\pi^0$ channel we
find in the $np\pi^+$ channel a strong influence of the $\Delta$ excitation
already at this energy close to threshold. In particular we find a $(3
cos^2\Theta + 1)$ dependence in the pion angular distribution, typical for a
pure s-channel $\Delta$ excitation and identical to that observed in the
$d\pi^+$ channel. Since the latter is understood by a s-channel resonance in
the $^1D_2$ $pn$ partial wave, we discuss an analogous scenario for the
$pn\pi^+$ channel.


title: On generic properties of finitely presented monoids and semigroups

abstract:
  We study the generic properties of finitely presented monoids and semigroups.
We show that for positive integers a > 1, k and m, the generic a-generator
k-relation monoid and semigroup presentation (defined in any of several
definite statistical senses) satisfy the small overlap condition C(m). It
follows that the generic monoid is torsion-free and J-trivial and, by a recent
result of the author, admits a linear time solution to its word problem and a
regular language of unique normal forms for its elements. Moreover, the uniform
word problem for finitely presented monoids is generically solvable in time
linear in the word lengths and quadratic in the presentation size. We also
prove some technical results about generic sets which may be of independent
interest.


title: A cocycle on the group of symplectic diffeomorphisms

abstract:
  We define a cocycle on the group of symplectic diffeomorphisms of a
symplectic manifold and investigate its properties. The main applications are
concerned with symplectic actions of discrete groups. For example, we give an
alternative proof of the Polterovich theorem about the distortion of cyclic
subgroups in finitely generated groups of Hamiltonian diffeomorphisms.


title: Transformation from the nonautonomous to standard NLS equations

abstract:
  In this paper we show a systematical method to obtain exact solutions of the
nonautonomous nonlinear Schr\"odinger (NLS) equation. An integrable condition
is first obtained by the Painlev\`e analysis, which is shown to be consistent
with that obtained by the Lax pair method. Under this condition, we present a
general transformation, which can directly convert all allowed exact solutions
of the standard NLS equation into the corresponding exact solutions of the
nonautonomous NLS equation. The method is quite powerful since the standard NLS
equation has been well studied in the past decades and its exact solutions are
vast in the literature. The result provides an effective way to control the
soliton dynamics. Finally, the fundamental bright and dark solitons are taken
as examples to demonstrate its explicit applications.


title:
Quantum phonon transport of molecular junctions amide-linked with carbon
  nanotubes: a first-principle study

abstract:
  Quantum phonon transport through benzene and alkane chains amide-linked with
single wall carbon nanotubes (SWCNTs) is studied within the level of density
functional theory. The force constant matrices are obtained from standard
quantum chemistry software. The phonon transmission and thermal conductance are
from the nonequilibrium Green's function and the mode-matching method. We find
that the ballistic thermal conductance is not sensitive to the compression or
stretching of the molecular junction. The terminating groups of the SWCNTs at
the cutting edges only influence the thermal conductance quantitatively. The
conductance of the benzene and alkane chains shows large difference. Analysis
of the transmission spectrum shows that (i) the low temperature thermal
conductance is mainly contributed by the SWCNT transverse acoustic modes, (ii)
the degenerate phonon modes show different transmission probability due to the
presence of molecular junction, (iii) the SWCNT twisting mode can hardly be
transmitted by the alkane chain. As a result, the ballistic thermal conductance
of alkane chains is larger than that of benzene chains below 38 K, while it is
smaller at higher temperature.


title:
Comparative study of macroscopic quantum tunneling in Bi_2Sr_2CaCu_2O_y
  intrinsic Josephson junctions with different device structures

abstract:
  We investigated macroscopic quantum tunneling (MQT) of
Bi$_2$Sr$_2$CaCu$_2$O$_y$ intrinsic Josephson junctions (IJJs) with two device
structures. One is a nanometer-thick small mesa structure with only two or
three IJJs and the other is a stack of a few hundreds of IJJs on a narrow
bridge structure. Experimental results of switching current distribution for
the first switching events from zero-voltage state showed a good agreement with
the conventional theory for a single Josephson junction, indicating that a
crossover temperature from thermal activation to MQT regime for the former
device structure was as high as that for the latter device structure. Together
with the observation of multiphoton transitions between quantized energy levels
in MQT regime, these results strongly suggest that the observed MQT behavior is
intrinsic to a single IJJ in high-$T_c$ cuprates, independent of device
structures. The switching current distribution for the second switching events
from the first resistive state, which were carefully distinguished from the
first switchings, was also compared between two device structures. In spite of
the difference in the heat transfer environment, the second switching events
for both devices were found to show a similar temperature-independent behavior
up to a much higher temperature than the crossover temperature for the first
switching. We argue that it cannot be explained in terms of the self-heating
owing to dissipative currents after the first switching. As possible
candidates, the MQT process for the second switching and the effective increase
of electronic temperature due to quasiparticle injection are discussed.


title:
Topological susceptibility in SU(2) Yang-Mills theory in the Hamiltonian
  approach in Coulomb gauge

abstract:
  The topological susceptibility is calculated within the Hamiltonian approach
to Yang-Mills theory in Coulomb gauge, using the vacuum wave functional
previously determined by a variational solution of the Yang-Mills Schroedinger
equation. The numerical result agrees qualitatively with the predictions of
lattice simulations.


title:
The influence of chemical composition on the properties of Cepheid
  stars. II-The iron content

abstract:
  The Cepheid period-luminosity (PL) relation is unquestionably one of the most
powerful tools at our disposal for determining the extragalactic distance
scale. While significant progress has been made in the past few years towards
its understanding and characterization both on the observational and
theoretical sides, the debate on the influence that chemical composition may
have on the PL relation is still unsettled. With the aim to assess the
influence of the stellar iron content on the PL relation in the V and K bands,
we have related the V-band and the K-band residuals from the standard PL
relations of Freedman et al. (2001) and Persson et al. (2004), respectively, to
[Fe/H]. We used direct measurements of the iron abundances of 68 Galactic and
Magellanic Cepheids from FEROS and UVES high-resolution and high
signal-to-noise spectra. We find a mean iron abundance ([Fe/H]) about solar
(sigma = 0.10) for our Galactic sample (32 stars), -0.33 dex (sigma = 0.13) for
the Large Magellanic Cloud (LMC) sample (22 stars) and -0.75 dex (sigma = 0.08)
for the Small Magellanic Cloud (SMC) sample (14 stars). Our abundance
measurements of the Magellanic Cepheids double the number of stars studied up
to now at high resolution. The metallicity affects the V-band Cepheid PL
relation and metal-rich Cepheids appear to be systematically fainter than
metal-poor ones. These findings depend neither on the adopted distance scale
for Galactic Cepheids nor on the adopted LMC distance modulus. Current data do
not allow us to reach a firm conclusion concerning the metallicity dependence
of the K-band PL relation. The new Galactic distances indicate a small effect,
whereas the old ones support a marginal effect.


title: Numerical study of ground state energy fluctuations in spin glasses

abstract:
  Using a stochastic algorithm introduced in a previous paper, we study the
finite size volume corrections and the fluctuations of the ground state energy
in the Sherrington-Kirkpatrick and the Edwards-Anderson models at zero
temperature. The algorithm is based on a suitable annealing procedure coupled
with a balanced greedy-reluctant strategy that drives the systems towards the
deepest minimum of the energy function.


title: Superconductivity of non- stoichiometric intermetallic compound NbB2

abstract:
  We report the synthesis, magnetic susceptibility and crystal structure
analysis for NbB2+x (x = 0.0 to 1.0) samples. The study facilitates in finding
a correlation among the lattice parameters, chemical composition and the
superconducting transition temperature Tc. Rietveld analysis is done on the X-
ray diffraction patterns of all synthesized samples to determine the lattice
parameters. The a parameter decreases slightly and has a random variation with
increasing x, while c parameter increases from 3.26 for pure NbB2 to 3.32 for
x=0.4 i.e. NbB2.4. With higher Boron content (x>0.4) the c parameter decreases
slightly. The stretching of lattice in c direction induces superconductivity in
the non- stoichiometric niobium boride. Pure NbB2 is non-superconductor while
the other NbB2+x (x>0.0) samples show diamagnetic signal in the temperature
range 8.9-11K. Magnetization measurements (M-H) at a fixed temperature of 5K
are also carried out in both increasing and decreasing directions of field. The
estimated lower and upper critical fields (Hc1 & Hc2) as viewed from M-H plots
are around 590 and 2000Oe respectively for NbB2.6 samples. In our case,
superconductivity is achieved in NbB2 by varying the Nb/B ratios, rather than
changing the processing conditions as reported by others.


title: Local differential calculus over Fedosov algebra

abstract:
  In this paper the local differential calculus over Fedosov algebra is
constructed using the trivialization isomorphism. The explicit formulas for
deformed derivations are given. The resulting calculus can be used as a
"building block" for a theory of Seiberg-Witten map with Fedosov type of
noncommutativity.


title:
Phenomenology of the Modified Newtonian Dynamics and the Concordance
  Cosmological Scenario

abstract:
  After reviewing the modified Newtonian dynamics (MOND) proposal, we advocate
that the associated phenomenology may actually not result from a modification
of Newtonian gravity, but from a mechanism of "gravitational polarization" of
some dipolar medium playing the role of dark matter. We then build a
relativistic model within standard general relativity to describe (at some
phenomenological level) the dipolar dark matter polarizable in a gravitational
field. The model naturally involves a cosmological constant, and is shown to
reduce to the concordance cosmological scenario (Lambda-CDM) at early
cosmological times. From the mechanism of gravitational polarization, we
recover the phenomenology of MOND in a typical galaxy at low redshift.
Furthermore, we show that the cosmological constant Lambda scales like a0^2,
where a0 is the constant MOND acceleration scale, in good agreement with
observations.


title:
Quantitative comparisons between finitary posterior distributions and
  Bayesian posterior distributions

abstract:
  The main object of Bayesian statistical inference is the determination of
posterior distributions. Sometimes these laws are given for quantities devoid
of empirical value. This serious drawback vanishes when one confines oneself to
considering a finite horizon framework. However, assuming infinite
exchangeability gives rise to fairly tractable {\it a posteriori} quantities,
which is very attractive in applications. Hence, with a view to a
reconciliation between these two aspects of the Bayesian way of reasoning, in
this paper we provide quantitative comparisons between posterior distributions
of finitary parameters and posterior distributions of allied parameters
appearing in usual statistical models.

categories: q-fin.ST math.PR math.ST stat.ME stat.TH


title:
Architecture of a massive parallel processing nano brain operating 100
  billion molecular neurons simultaneously

abstract:
  Molecular machines may resolve three distinct bottlenecks of scientific
advancement. Nanofactories (Phoenix, 2003) composed of MM may produce
atomically perfect products spending negligible amount of energy (Hess, 2004)
thus alleviating the energy crisis. Computers made by MM operating thousands of
bits at a time may match biological processors mimicking creativity and
intelligence (Hall, 2007), thus far considered as the prerogative of nature.
State-of-the-art brain surgeries are not yet fatal-less, MMs guided by a
nano-brain may execute perfect bloodless surgery (Freitas, 2005). Even though
all three bottlenecks converge to a single necessity of nano-brain, futurists
and molecular engineers have remained silent on this issue. Our recent
invention of 16 bit parallel processor is a first step in this direction
(Bandyopadhyay, 2008). However, the device operates inside ultra-high vacuum
chamber. For practical application, one needs to design a 3 D standalone
architecture. Here, we identify the minimum nano-brain functions for practical
applications and try to increase the size from 2 nm to 20 micro-m.


title: Physical Property Characterization of Bulk MgB2 Superconductor

abstract:
  We report synthesis, structure/micro-structure, resistivity under magnetic
field [R(T)H], Raman spectra, thermoelectric power S(T), thermal conductivity
K(T), and magnetization of ambient pressure argon annealed polycrystalline bulk
samples of MgB2, processed under identical conditions. The compound
crystallizes in hexagonal structure with space group P6/mmm. Transmission
electron microscopy (TEM) reveals electron micrographs showing various types of
defect features along with the presence of 3-4nm thick amorphous layers forming
the grain boundaries of otherwise crystalline MgB2. Raman spectra of the
compound at room temperature exhibited characteristic phonon peak at 600 cm-1.
Superconductivity is observed at 37.2K by magnetic susceptibility C(T),
resistivity R(T), thermoelectric power S(T), and thermal conductivity K(T)
measurements. The power law fitting of R(T) give rise to Debye temperature at
1400K which is found consistent with the theoretical fitting of S(T),
exhibiting ThetaD of 1410K and carrier density of 3.81x 1028/m3. Thermal
conductivity K(T) shows a jump at 38K, i.e., at Tc, which was missing in some
earlier reports. Critical current density (Jc) of up to 105 A/cm2 in 1-2T
(Tesla) fields at temperatures (T) of up to 10K is seen from magnetization
measurements. The irreversibility field, defined as the field related to
merging of M(H) loops is found to be 78, 68 and 42 kOe at 4, 10 and 20K
respectively. The superconducting performance parameters viz. irreversibility
field (Hirr) and critical current density Jc(H) of the studied MgB2 are
improved profoundly with addition of nano-SiC and nano-Diamond. The physical
property parameters measured for polycrystalline MgB2 are compared with earlier
reports and a consolidated insight of various physical properties is presented.


title:
Total forces in the diffusion Monte Carlo method with nonlocal
  pseudopotentials

abstract:
  We report exact expressions for atomic forces in the diffusion Monte Carlo
(DMC) method when using nonlocal pseudopotentials. We present approximate
schemes for estimating these expressions in both mixed and pure DMC
calculations, including the pseudopotential Pulay term which has not previously
been calculated and the Pulay nodal term which has not been calculated for real
systems in pure DMC simulations. Harmonic vibrational frequencies and
equilibrium bond lengths are derived from the DMC forces and compared with
those obtained from DMC potential energy curves. Results for four small
molecules show that the equilibrium bond lengths obtained from our best force
and energy calculations differ by less than 0.002 Angstrom.


title: Spatial homogenization in a stochastic network with mobility

abstract:
  A stochastic model for a mobile network is studied. Users enter the network,
and then perform independent Markovian routes between nodes where they receive
service according to the Processor-Sharing policy. Once their service
requirement is satisfied, they leave the system. The stability region is
identified via a fluid limit approach, and strongly relies on a "spatial
homogenization" property: at the fluid level, customers are instantaneously
distributed across the network according to the stationary distribution of
their Markovian dynamics and stay distributed as such as long as the network is
not empty. In the unstable regime, spatial homogenization almost surely holds
asymptotically as time goes to infinity (on the normal scale), telling how the
system fills up. One of the technical achievements of the paper is the
construction of a family of martingales associated to the multidimensional
process of interest, which makes it possible to get crucial estimates for
certain exit times.


title: How shall we use the proteomics toolbox for biomarker discovery?

abstract:
  Biomarker discovery for clinical purposes is one of the major areas in which
proteomics is used. However, despite considerable effort, the successes have
been relatively scarce. In this perspective paper, we try to highlight and
analyze the main causes for this limited success, and to suggest alternate
strategies, which will avoid them, without eluding the foreseeable weak points
of these strategies. Two major strategies are analyzed, namely, the switch from
body fluids to cell and tissues for the initial biomarker discovery step or, if
body fluids must be analyzed, the implementation of highly selective protein
selection strategies.


title: Antiproton collisions with molecular hydrogen

abstract:
  Theoretical antiproton and proton cross sections for ionization and
excitation of hydrogen molecules as well as energy spectra of the ionized
electrons were calculated in the impact-energy range from 8 to 4000 keV. The
cross sections were computed with the close-coupling formulation of the
semi-classical impact-parameter method. The target was described using a
one-active electron model centered on the target and assuming a fixed
internuclear distance during the collision process. The dependence of the
ionization cross sections on the internuclear distance is examined. The present
cross sections are compared with experimental and theoretical data from the
literature. For impact energies E > 90 keV the obtained results for ionization
by antiproton impact are comparable to the experimental data while they
disagree for energies E < 80 keV.


title:
Self-similarity parameter estimation and reproduction property for
  non-Gaussian Hermite processes

abstract:
  We consider the class of all the Hermite processes $(Z_{t}^{(q,H)})_{t\in
\lbrack 0,1]}$ of order $q\in \mathbf{N}^{\ast}$ and with Hurst parameter $%
H\in (\frac{1}{2},1)$. The process $Z^{(q,H)}$ is $H$-selfsimilar, it has
stationary increments and it exhibits long-range dependence identical to that
of fractional Brownian motion (fBm). For $q=1$, $Z^{(1,H)}$ is fBm, which is
Gaussian; for $q=2$, $Z^{(2,H)}$ is the Rosenblatt process, which lives in the
second Wiener chaos; for any $q>2$, $Z^{(q,H)}$ is a process in the $q$th
Wiener chaos. We study the variations of $Z^{(q,H)}$ for any $q$, by using
multiple Wiener -It\^{o} stochastic integrals and Malliavin calculus. We prove
a reproduction property for this class of processes in the sense that the terms
appearing in the chaotic decomposition of their variations give rise to other
Hermite processes of different orders and with different Hurst parameters. We
apply our results to construct a strongly consistent estimator for the
self-similarity parameter $H$ from discrete observations of $Z^{(q,H)}$; the
asymptotics of this estimator, after appropriate normalization, are proved to
be distributed like a Rosenblatt random variable (value at time $1$ of a
Rosenblatt process).with self-similarity parameter $1+2(H-1)/q$.


title: Influence of DNA on Ag(I)-C-Phycocyanin complexes

abstract:
  The effects of DNA on the fluorescence of silver phycocyanin complexes were
investigated. It was shown, that the fluorescence intensity of phycocyanin
decreases, when silver ions are added but the following DNA addition gives rise
to fluorescence buildup. Fluorescence spectroscopy provides insight of silver
phycocyanin interactions. Fluorescence measurements demostrate phycocyanin
quenching of silver emission intensities. SternVolmer quenching constant was
obtained from the linear quenching plot. Blue shifts in the fluorescence
spectra were observed during silver binding to phycocyanin.


title: Lorentz Violation and Ultrahigh-Energy Photons

abstract:
  The propagation of photons, electrons and positrons at ultra-high energies
above 10^{19} eV can be changed considerably if the dispersion relations of
these particles are modified by terms suppressed by powers of the Planck scale.
We recently pointed out that the current non-observation of photons in the
ultra-high energy cosmic ray flux at such energies can put strong constraints
on such modified dispersion relations. In the present work we generalize these
constraints to all three Lorentz invariance breaking parameters that can occur
in the dispersion relations for photons, electrons and positrons at first and
second order suppression with the Planck scale. We also show how the excluded
regions in these three-dimensional parameter ranges would be extended if
ultra-high energy photons were detected in the future.