title: Mass, Charge and Motion in Covariant Gravity Theories

abstract:
  Previous work established a universal form for the equation of motion of
small bodies in theories of a metric and other tensor fields that have
second-order field equations following from a covariant Lagrangian in four
spacetime dimensions. Differences in the motion of the "same" body in two
different theories are entirely accounted for by differences in the body's
effective mass and charges in those different theories. Previously the process
of computing the mass and charges for a particular body was left implicit, to
be determined in each particular theory as the need arises. I now obtain
explicit expressions for the mass and charges of a body as surface integrals of
the fields it generates, where the integrand is constructed from the symplectic
current for the theory. This allows the entire prescription for computing the
motion of a small body to be written down in a few lines, in a manner universal
across bodies and theories. For simplicity I restrict to scalar and vector
fields (in addition to the metric), but there is no obstacle to treating
higher-rank tensor fields. I explicitly apply the prescription to work out
specific equations for various body types in Einstein gravity, generalized
Brans-Dicke theory (in both Jordan and Einstein frames), Einstein-Maxwell
theory and the Will-Nordvedt vector-tensor theory. In the scalar-tensor case,
this clarifies the origin and meaning of the "sensitivities" defined by Eardley
and others, and provides explicit formulae for their evaluation.


title: Computable Compressed Matrices

abstract:
  The biggest cost of computing with large matrices in any modern computer is
related to memory latency and bandwidth. The average latency of modern RAM
reads is 150 times greater than a clock step of the processor. Throughput is a
little better but still 25 times slower than the CPU can consume. The
application of bitstring compression allows for larger matrices to be moved
entirely to the cache memory of the computer, which has much better latency and
bandwidth (average latency of L1 cache is 3 to 4 clock steps). This allows for
massive performance gains as well as the ability to simulate much larger models
efficiently. In this work, we propose a methodology to compress matrices in
such a way that they retain their mathematical properties. Considerable
compression of the data is also achieved in the process Thus allowing for the
computation of much larger linear problems within the same memory constraints
when compared with the traditional representation of matrices.


title:
An entangling quantum-logic gate operated with an ultrabright single
  photon-source

abstract:
  We demonstrate unambiguous entangling operation of a photonic quantum-logic
gate driven by an ultrabright solid-state single-photon source.
Indistinguishable single photons emitted by a single semiconductor quantum dot
in a micropillar optical cavity are used as target and control qubits. For a
source brightness of 0.56 collected photons-per-pulse, the measured truth table
has an overlap with the ideal case of 68.4%, increasing to 73.0% for a source
brightness of 0.17 photons- per-pulse. The gate is entangling: at a source
brightness of 0.48, the Bell-state fidelity is above the entangling threshold
of 50%, and reaches 71.0% for a source brightness of 0.15.


title: Duality phases and halved maximal D=4 supergravity

abstract:
  The duality angles deformation developed by de Roo and Wagemans within the
context of N=4 gauged supergravity is used in order to study certain classes of
gaugings of N=8 supergravity, namely, those that are consistent when halving
the maximal D=4 theory. After reviewing the truncation process from N=8 to N=4
supergravity in terms of the embedding tensor formalism, the de Roo-Wagemans
phases method is implemented for solving the resulting constraints on the
gauging parameters by means of the Schon-Weidner ansatz. In contrast with the
twenty semisimple N=4 gaugings admitting more than a single SL(2) angle
deforming their decompositions reported in the literature, it is proven that
only three of them can be embedded back into the N=8 theory. The scalar
potential derived for only two of these gauge groups exhibits an extremum in
the origin of the scalar manifold. These extrema are not stable under
fluctuations of all the scalar fields.


title:
Quantum error correction and detection: quantitative analysis of a
  coherent-state amplitude damping code

abstract:
  We re-examine a non-Gaussian quantum error correction code designed to
protect optical coherent-state qubits against errors due to an amplitude
damping channel. We improve on a previous result [Phys. Rev. A 81, 062344
(2010)] by providing a tighter upper bound on the performance attained when
considering realistic assumptions which constrain the operation of the gates
employed in the scheme. The quantitative characterization is performed through
measures of fidelity and concurrence, the latter obtained by employing the code
as an entanglement distillation protocol. We find that, when running the code
in fully-deterministic error correction mode, direct transmission can only be
beaten for certain combinations of channel and input state parameters, whereas
in error detection mode, the usage of higher repetition encodings remains
beneficial throughout.


title: Superluminality in the Bi- and Multi- Galileon

abstract:
  We re-explore the Bi- and Multi-Galileon models with trivial asymptotic
conditions at infinity and show that propagation of superluminal fluctuations
is a common and unavoidable feature of these theories, unlike previously
claimed in the literature. We show that all Multi-Galileon theories containing
a Cubic Galileon term exhibit superluminalities at large distances from a point
source, and that even if the Cubic Galileon is not present one can always find
sensible matter distributions in which there are superluminal modes at large
distances. In the Bi-Galileon case we explicitly show that there are always
superluminal modes around a point source even if the Cubic Galileon is not
present. Finally, we briefly comment on the possibility of avoiding
superluminalities by modifying the asymptotic conditions at infinity.


title: Observations of the Crab Pulsar with VERITAS

abstract:
  The Fermi space telescope has detected over 100 pulsars. These discoveries
have ushered in a new era of pulsar astrophysics at gamma-ray energies.
Gamma-ray pulsars, regardless of whether they are young, old, radio-quiet etc,
all exhibit a seemingly unifying characteristic: a spectral energy distribution
which takes the form of a power law with an exponential cut-off occurring
between ~1 and ~10 GeV. The single known exception to this is the Crab pulsar,
which was recently discovered to emit pulsed gamma rays at energies exceeding a
few hundred GeV. Here we present an update on observations of the Crab pulsar
above 100 GeV with VERITAS. We show some new results from a joint
gamma-ray/radio observational campaign to search for a correlation between
giant radio pulses and pulsed VHE emission from the Crab pulsar. We also
present some preliminary results on Lorentz invariance violation tests
performed using Fermi and VERITAS observations of the Crab pulsar.


title: AutoSynch: An Automatic-Signal Monitor Based on Predicate Tagging

abstract:
  Most programming languages use monitors with explicit signals for
synchronization in shared-memory programs. Requiring program- mers to signal
threads explicitly results in many concurrency bugs due to missed
notifications, or notifications on wrong condition variables. In this paper, we
describe an implementation of an au- tomatic signaling monitor in Java called
AutoSynch that eliminates such concurrency bugs by removing the burden of
signaling from the programmer. We show that the belief that automatic signaling
monitors are prohibitively expensive is wrong. For most problems, programs
based on AutoSynch are almost as fast as those based on explicit signaling. For
some, AutoSynch is even faster than explicit signaling because it never uses
signalAll, whereas the programmers end up using signalAll with the explicit
signal mechanism. AutoSynch achieves efficiency in synchronization based on
three novel ideas. We introduce an operation called globalization that enables
the predicate evaluation in every thread, thereby reducing context switches
during the execution of the program. Secondly, AutoSynch avoids signalAll by
using a property called relay invari- ance that guarantees that whenever
possible there is always at least one thread whose condition is true which has
been signaled. Finally, AutoSynch uses a technique called predicate tagging to
efficiently determine a thread that should be signaled. To evaluate the effi-
ciency of AutoSynch, we have implemented many different well- known
synchronization problems such as the producers/consumers problem, the
readers/writers problems, and the dining philosophers problem. The results show
that AutoSynch is almost as efficient as the explicit-signal monitor and even
more efficient for some cases.


title:
Competition between extinction and enhancement in surface enhanced Raman
  spectroscopy

abstract:
  Conjugated metallic nanoparticles are a promising means to achieve
ultrasensitive and multiplexed sensing in intact three-dimensional samples,
especially for biological applications, via surface enhanced Raman scattering
(SERS). We show that enhancement and extinction are linked and compete in a
collection of metallic nanoparticles. Counterintuitively, the Raman signal
vanishes when nanoparticles are excited at their plasmon resonance, while
increasing nanoparticle concentrations at off-resonance excitation sometimes
leads to decreased signal. We develop an effective medium theory that explains
both phenomena. Optimal choices of excitation wavelength, individual particle
enhancement factor and concentrations are indicated.


title: Baryonic violation of R-parity from anomalous $U(1)_H$

abstract:
  Supersymmetric scenarios with R-parity conservation are becoming very
constrained due to the lack of missing energy signals, thus motivating those
scenarios with R-parity violation. In view of this, we consider a
supersymmetric model with R-parity violation and extended by an anomalous
horizontal $U(1)_H$ symmetry, where a self-consistent framework with
baryon-number violation is achieved along with a proper supression for lepton
number violating dimension-5 operators in order to keep a proton decay safe.
With the introduction of right-handed neutrinos both Dirac and Majorana masses
can be accommodated within this model. The implications for collider physics
are discussed.


title:
Assessing quantum error correction: fidelity and entanglement measures
  with application to photonic codes

abstract:
  By interpreting the well-known, qualitative criteria for the existence of
quantum error correction (QEC) codes by Knill and Laflamme from a quantitative
perspective, we propose a figure of merit for assessing a QEC scheme based on
the average fidelity between codewords. This enables us to quantify the
performance of a protocol as a whole, including errors beyond the correctable
set. Various examples are calculated for photonic qubit codes dealing with the
experimentally relevant case of photon loss, demonstrating the advantages of
the new measure. In the context of continuous-variable QEC, our
codeword-overlap measure can be used to reproduce, in a different way with no
need for calculating entanglement measures, a previous result concerning the
impossibility of improving transmission of Gaussian states through Gaussian
channels via Gaussian operations alone.


title: The Formation of Pluto's Low Mass Satellites

abstract:
  Motivated by the New Horizons mission, we consider how Pluto's small
satellites -- currently Styx, Nix, Kerberos, and Hydra -- grow in debris from
the giant impact that forms the Pluto-Charon binary. After the impact, Pluto
and Charon accrete some of the debris and eject the rest from the binary orbit.
During the ejection, high velocity collisions among debris particles produce a
collisional cascade, leading to the ejection of some debris from the system and
enabling the remaining debris particles to find stable orbits around the
binary. Our numerical simulations of coagulation and migration show that
collisional evolution within a ring or a disk of debris leads to a few small
satellites orbiting Pluto-Charon. These simulations are the first to
demonstrate migration-induced mergers within a particle disk. The final
satellite masses correlate with the initial disk mass. More massive disks tend
to produce fewer satellites. For the current properties of the satellites, our
results strongly favor initial debris masses of 3-10 x 10^{19} g and current
satellite albedos of roughly 0.4-1. We also predict an ensemble of smaller
satellites with radii less than roughly 1-3 km, and very small particles, with
radii of roughly 1-100 cm and optical depth smaller than 10^-10. These objects
should have semimajor axes outside the current orbit of Hydra.


title:
Systems, environments, and soliton rate equations: A non-Kolmogorovian
  framework for population dynamics

abstract:
  Soliton rate equations are based on non-Kolmogorovian models of probability
and naturally include autocatalytic processes. The formalism is not widely
known but has great unexplored potential for applications to systems
interacting with environments. Beginning with links of contextuality to
non-Kolmogorovity we introduce the general formalism of soliton rate equations
and work out explicit examples of subsystems interacting with environments. Of
particular interest is the case of a soliton autocatalytic rate equation
coupled to a linear conservative environment, a formal way of expressing
seasonal changes. Depending on strength of the system-environment coupling we
observe phenomena analogous to hibernation or even complete blocking of decay
of a population.


title:
Matters of Gravity, The Newsletter of the Topical Group on Gravitation
  of the American Physical Society, Volume 41, Winter 2013

abstract:
  GGR News:
  we hear that...
  100 years ago
  GGR program at the APS meeting in Denver, CO


title: Inverse Signal Classification for Financial Instruments

abstract:
  The paper presents new machine learning methods: signal composition, which
classifies time-series regardless of length, type, and quantity; and
self-labeling, a supervised-learning enhancement. The paper describes further
the implementation of the methods on a financial search engine system using a
collection of 7,881 financial instruments traded during 2011 to identify
inverse behavior among the time-series.


title: Social Recommendations within the Multimedia Sharing Systems

abstract:
  The social recommender system that supports the creation of new relations
between users in the multimedia sharing system is presented in the paper. To
generate suggestions the new concept of the multirelational social network was
introduced. It covers both direct as well as object-based relationships that
reflect social and semantic links between users. The main goal of the new
method is to create the personalized suggestions that are continuously adapted
to users' needs depending on the personal weights assigned to each layer from
the social network. The conducted experiments confirmed the usefulness of the
proposed model.


title:
The Meaning and Consequences of Star Formation Criteria in Galaxy Models
  with Resolved Stellar Feedback

abstract:
  We consider the effects of different star formation criteria on galactic
scales, in high-resolution simulations with explicitly resolved GMCs and
stellar feedback. We compare: (1) a self-gravity criterion (based on the local
virial parameter and the assumption that self-gravitating gas collapses to high
density in a free-fall time), (2) a fixed density threshold, (3) a
molecular-gas law, (4) a temperature threshold, (5) a Jeans-instability
requirement, (6) a criteria that cooling times be shorter than dynamical times,
and (7) a convergent-flow criterion. We consider these both MW-like and
high-density (starburst) galaxies. With feedback present, all models produce
identical integrated star formation rates (SFRs), in agreement with the
Kennicutt relation. Without feedback all produce orders-of-magnitude excessive
SFRs. This is totally dependent on feedback and independent of the SF law.
However, the spatial and density distribution of SF depend strongly on the SF
criteria. Because cooling rates are generally fast and gas is turbulent,
criteria (4)-(7) are 'weak' and spread SF uniformly over the disk (above
densities n~0.01-0.1 cm^-3). A molecular criterion (3) localizes to higher
densities, but still a wide range; for Z Z_solar, it is similar to a density
threshold at n~1 cm^-3 (well below mean densities in the MW center or
starbursts). Fixed density thresholds (2) can always select the highest
densities, but must be adjusted for simulation resolution and galaxy
properties; the same threshold that works in a MW-like simulation will select
nearly all gas in a starburst. Binding criteria (1) tend to adaptively select
the largest over-densities, independent of galaxy model or resolution, and
automatically predict clustered SF. We argue that this SF model is most
physically-motivated and presents significant numerical advantages in
large-dynamic range simulations.


title: GRB Flares: UV/Optical Flaring (Paper I)

abstract:
  We present a new algorithm for the detection of flares in gamma-ray burst
(GRB) light curves and use this algorithm to detect flares in the UV/optical.
The algorithm makes use of the Bayesian Information Criterion (BIC) to analyze
the residuals of the fitted light curve, removing all major features, and to
determine the statistically best fit to the data by iteratively adding
additional `breaks' to the light curve. These additional breaks represent the
individual components of the detected flares: T_start, T_stop, and T_peak. We
present the detection of 119 unique flaring periods detected by applying this
algorithm to light curves taken from the Second Swift Ultraviolet/Optical
Telescope (UVOT) GRB Afterglow Catalog. We analyzed 201 UVOT GRB light curves
and found episodes of flaring in 68 of the light curves. For those light curves
with flares, we find an average number of ~2 flares per GRB. Flaring is
generally restricted to the first 1000 seconds of the afterglow, but can be
observed and detected beyond 10^5 seconds. More than 80% of the flares detected
are short in duration with Delta t/t of < 0.5. Flares were observed with flux
ratios relative to the underlying light curve of between 0.04 to 55.42. Many of
the strongest flares were also seen at greater than 1000 seconds after the
burst.


title:
Combining clustering and abundances of galaxy clusters to test cosmology
  and primordial non-Gaussianity

abstract:
  We present the clustering of galaxy clusters as a useful addition to the
common set of cosmological observables. The clustering of clusters probes the
large-scale structure of the Universe, extending galaxy clustering analysis to
the high-peak, high-bias regime. Clustering of galaxy clusters complements the
traditional cluster number counts and observable-mass relation analyses,
significantly improving their constraining power by breaking existing
calibration degeneracies. We use the maxBCG galaxy clusters catalogue to
constrain cosmological parameters and cross-calibrate the mass-observable
relation, using cluster abundances in richness bins and weak-lensing mass
estimates. We then add the redshift-space power spectrum of the sample,
including an effective modelling of the weakly non-linear contribution and
allowing for an arbitrary photometric redshift smoothing. The inclusion of the
power spectrum data allows for an improved self-calibration of the scaling
relation. We find that the inclusion of the power spectrum typically brings a
$\sim 50$ per cent improvement in the errors on the fluctuation amplitude
$\sigma_8$ and the matter density $\Omega_{\mathrm{m}}$. Finally, we apply this
method to constrain models of the early universe through the amount of
primordial non-Gaussianity of the local type, using both the variation in the
halo mass function and the variation in the cluster bias. We find a constraint
on the amount of skewness $f_{\mathrm{NL}} = 12 \pm 157 $ ($1\sigma$) from the
cluster data alone.


title:
Quantum Monte Carlo study of nonequilibrium transport through a quantum
  dot coupled to normal and superconducting leads

abstract:
  We investigate the nonequilibrium phenomena through the quantum dot coupled
to the normal and superconducting leads using a weak-coupling continuous-time
Monte Carlo method. Calculating the time evolution of particle number, double
occupancy, and pairing correlation at the quantum dot, we discuss how the
system approaches the steady state. We also deduce the steady current through
the quantum dot beyond the linear response region. It is clarified that the
interaction decreases the current in the Kondo-singlet dominant region. On the
other hand, when the quantum dot is tightly coupled to the superconducting
lead, the current is increased by the introduction of the Coulomb interaction,
which originates from the competition between the Kondo and proximity effects.
Transient currents induced by the interaction quench are also addressed.


title:
Higgs diphoton rate and mass enhancement with vector-like leptons and
  the scale of supersymmetry

abstract:
  Analysis of contributions from vector-like leptonic supermultiplets to the
Higgs diphoton decay rate and to the Higgs boson mass is given. Corrections
arising from the exchange of the new leptons and their super-partners, as well
as their mirrors are computed analytically and numerically. We also study the
correlation between the enhanced Higgs diphoton rate and the Higgs mass
corrections. Specifically, we find two branches in the numerical analysis: on
the lower branch the diphoton rate enhancement is flat while on the upper
branch it has a strong correlation with the Higgs mass enhancement. It is seen
that a factor of 1.4-1.8 enhancement of the Higgs diphoton rate on the upper
branch can be achieved, and a 4-10 GeV positive correction to the Higgs mass
can also be obtained simultaneously. The effect of this extra contribution to
the Higgs mass is to release the constraint on weak scale supersymmetry,
allowing its scale to be lower than in the theory without extra contributions.
The vector-like supermultiplets also have collider implications which can be
tested at the LHC and at the ILC.


title: Galaxy Interactions in Compact Groups I : The Galactic Winds of HCG16

abstract:
  Using the WiFeS integral field spectrograph, we have undertaken a series of
observations of star-forming galaxies in Compact Groups. In this first paper
dedicated to the project, we present the analysis of the spiral galaxy NGC838,
a member of the Hickson Compact Group 16, and of its galactic wind. Our
observations reveal that the wind forms an asymmetric, bipolar, rotating
structure, powered by a nuclear starburst. Emission line ratio diagnostics
indicate that photoionization is the dominant excitation mechanism at the base
of the wind. Mixing from slow shocks (up to 20%) increases further out along
the outflow axis. The asymmetry of the wind is most likely caused by one of the
two lobes of the wind bubble bursting out of its HI envelope, as indicated by
line ratios and radial velocity maps. The characteristics of this galactic wind
suggest that it is caught early (a few Myr) in the wind evolution sequence. The
wind is also quite different to the galactic wind in the partner galaxy NGC839
which contains a symmetric, shock-excited wind. Assuming that both galaxies
have similar interaction histories, the two different winds must be a
consequence of the intrinsic properties of NGC838 and NGC839 and their
starbursts.


title: Tensionless Strings and Galilean Conformal Algebra

abstract:
  We find an intriguing link between the symmetries of the tensionless limit of
closed string theory and the 2-dimensional Galilean Conformal Algebra (2d GCA).
2d GCA has been discussed in the context of the non-relativistic limit of
AdS/CFT and more recently in flat-space holography as the proposed symmetry
algebra of the field theory dual to 3d Minkowski spacetimes. It is best
understood as a contraction of two copies of the Virasoro algebra. In this
note, we link this to the tensionless limit of bosonic closed string theory. We
show how it emerges naturally as a contraction of the residual gauge symmetries
of the tensile string in the conformal gauge. We also discuss a possible "dual"
interpretation in terms of a point-particle like limit.


title:
Recovering Redshift Distributions with Cross-Correlations: Pushing The
  Boundaries

abstract:
  Determining accurate redshift distributions for very large samples of objects
has become increasingly important in cosmology. We investigate the impact of
extending cross-correlation based redshift distribution recovery methods to
include small scale clustering information. The major concern in such work is
the ability to disentangle the amplitude of the underlying redshift
distribution from the influence of evolving galaxy bias. Using multiple
simulations covering a variety of galaxy bias evolution scenarios, we
demonstrate reliable redshift recoveries using linear clustering assumptions
well into the non-linear regime for redshift distributions of narrow redshift
width. Including information from intermediate physical scales balances the
increased information available from clustering and the residual bias incurred
from relaxing of linear constraints. We discuss how breaking a broad sample
into tomographic bins can improve estimates of the redshift distribution, and
present a simple bias removal technique using clustering information from the
spectroscopic sample alone.


title: Thermal Processes Governing Hot-Jupiter Radii

abstract:
  There have been many proposed explanations for the larger-than-expected radii
of some transiting hot Jupiters, including either stellar or orbital energy
deposition deep in the atmosphere or deep in the interior. In this paper, we
explore the important influences on hot-Jupiter radius evolution of (i)
additional heat sources in the high atmosphere, the deep atmosphere, and deep
in the convective interior; (ii) consistent cooling of the deep interior
through the planetary dayside, nightside, and poles; (iii) the degree of heat
redistribution to the nightside; and (iv) the presence of an upper atmosphere
absorber inferred to produce anomalously hot upper atmospheres and inversions
in some close-in giant planets. In particular, we compare the radius expansion
effects of atmospheric and deep-interior heating at the same power levels and
derive the power required to achieve a given radius increase when night-side
cooling is incorporated. We find that models that include consistent day/night
cooling are more similar to isotropically irradiated models when there is more
heat redistributed from the dayside to the nightside. In addition, we consider
the efficacy of ohmic heating in the atmosphere and/or convective interior in
inflating hot Jupiters. Among our conclusions are that (i) the most highly
irradiated planets cannot stably have uB > (10 km/s Gauss) over a large
fraction of their daysides, where u is the zonal wind speed and B is the
dipolar magnetic field strength in the atmosphere, and (ii) that ohmic heating
cannot in and of itself lead to a runaway in planet radius.


title:
Efficient method of finding scaling exponents from finite-size
  Monte-Carlo simulations

abstract:
  Monte-Carlo simulations are routinely used for estimating the scaling
exponents of complex systems. However, due to finite-size effects, determining
the exponent values is often difficult and not reliable. Here we present a
novel technique of dealing with the problem of finite-size scaling. This new
method allows not only to decrease the uncertainties of the scaling exponents,
but makes it also possible to determine the exponents of the asymptotic
corrections to the scaling laws. The efficiency of the technique is
demonstrated by finding the scaling exponent of uncorrelated percolation
cluster hulls.


title:
Astrophysical Tests of Modified Gravity: the Morphology and Kinematics
  of Dwarf Galaxies

abstract:
  This paper is the third in a series on tests of gravity using observations of
stars and nearby dwarf galaxies. We carry out four distinct tests using
published data on the kinematics and morphology of dwarf galaxies, motivated by
the theoretical work of Hui et al. (2009) and Jain and Vanderplas (2011). In a
wide class of gravity theories a scalar field couples to matter and provides an
attractive fifth force. Due to their different self-gravity, stars and gas may
respond differently to the scalar force leading to several observable
deviations from standard gravity. HI gas, red giant stars and main sequence
stars can be displaced relative to each other, and the stellar disk can display
warps or asymmetric rotation curves aligned with external potential gradients.
To distinguish the effects of modified gravity from standard astrophysical
phenomena, we use a control sample of galaxies that are expected to be screened
from the fifth force. In all cases we find no significant deviation from the
null hypothesis of general relativity. The limits obtained from dwarf galaxies
are not yet competitive with the limits from cepheids obtained in our first
paper, but can be improved to probe regions of parameter space that are
inaccessible using other tests. We discuss how our methodology can be applied
to new radio and optical observations of nearby galaxies.


title:
Performance of Spatially-Coupled LDPC Codes and Threshold Saturation
  over BICM Channels

abstract:
  We study the performance of binary spatially-coupled low-density parity-check
codes (SC-LDPC) when used with bit-interleaved coded-modulation (BICM) schemes.
This paper considers the cases when transmission takes place over additive
white Gaussian noise (AWGN)channels and Rayleigh fast-fading channels. The
technique of upper bounding the maximum-a-posteriori (MAP) decoding performance
of LDPC codes using an area theorem is extended for BICM schemes. The upper
bound is computed for both the optimal MAP demapper and the suboptimal
max-log-MAP (MLM) demapper. It is observed that this bound approaches the noise
threshold of BICM channels for regular LDPC codes with large degrees. The rest
of the paper extends these techniques to SC-LDPC codes and the phenomenon of
threshold saturation is demonstrated numerically. Based on numerical evidence,
we conjecture that the belief-propagation (BP) decoding threshold of SC-LDPC
codes approaches the MAP decoding threshold of the underlying LDPC ensemble on
BICM channels. Numerical results also show that SC-LDPC codes approach the BICM
capacity over different channels and modulation schemes.


title: Single-qubit gates in two steps with rotation axes in a single plane

abstract:
  Any single-qubit unitary operation or quantum gate can be considered a
rotation. Typical experimental implementations of single-qubit gates involve
two or three fixed rotation axes, and up to three rotation steps. Here we show
that, if the rotation axes can be tuned arbitrarily in a fixed plane, then two
rotation steps are sufficient for implementing a single-qubit gate, and one
rotation step is sufficient for implementing a state transformation. The
results are relevant for "exchange-only" logical qubits encoded in three-spin
blocks, which are important for universal quantum computation in decoherence
free subsystems and subspaces.


title:
A Sufficient Condition for Partial Ensemble Controllability of Bilinear
  Schr\"odinger Equations with Bounded Coupling Terms

abstract:
  This note presents a sufficient condition for partial approximate ensemble
controllability of a set of bilinear conservative quantum systems in an
infinite dimensional Hilbert space. The proof relies on classical geometric and
averaging control techniques applied on finite dimensional approximation of the
infinite dimensional system. The results are illustrated with the planar
rotation of a linear molecule.


title: Limit of spin squeezing in trapped Bose-Einstein condensates

abstract:
  The evolution of an interacting two-component Bose-Einstein condensate from
an initial phase state leads to a spin squeezed state that may be used in
atomic clocks to increase the signal-to-noise ratio, opening the way to quantum
metrology. The efficiency of spin squeezing is limited by the finite
temperature of the gas, as was shown theoretically in a spatially homogeneous
system. Here we determine the limit of spin squeezing in the realistic trapped
case, with classical field simulations, and with a completely analytical
treatment that includes the quantum case.


title:
PeV neutrinos from intergalactic interactions of cosmic rays emitted by
  active galactic nuclei

abstract:
  The observed very high energy spectra of distant blazars are well described
by secondary gamma rays produced in line-of-sight interactions of cosmic rays
with background photons. In the absence of the cosmic-ray contribution, one
would not expect to observe very hard spectra from distant sources, but the
cosmic ray interactions generate very high energy gamma rays relatively close
to the observer, and they are not attenuated significantly. The same
interactions of cosmic rays are expected to produce a flux of neutrinos with
energies peaked around 1 PeV. We show that the diffuse isotropic neutrino
background from many distant sources can be consistent with the neutrino events
recently detected by the IceCube experiment. We also find that the flux from
any individual nearby source is insufficient to account for these events. The
narrow spectrum around 1 PeV implies that some active galactic nuclei can
accelerate protons to EeV energies.


title:
Classifying convex compact ancient solutions to the affine curve
  shortening flow

abstract:
  In this paper we classify convex compact ancient solutions to the affine
curve shortening flow: namely, any convex compact ancient solution to the
affine curve shortening flow must be a shrinking ellipse. The method combines a
rescaling argument inspired by \cite{Wang}, affine invariance of the equation
and monotonicity of the affine isoperimetric ratio. We will give two proofs.
The essential ideas are related, but the first one uses level set represenation
of the evolution. The second proof employs Schauder's estimates, and it also
provides a new simple proof for the corresponding classification result to the
higher dimensional affine normal flow.


title:
Corrections to the paper "The boundedness of certain sublinear operator
  in the weighted variable Lebesgue spaces"

abstract:
  In this paper author was proved the boundedness of the multidimensional Hardy
type operator in weighted Lebesgue spaces with a variable exponent. As an
application we prove the boundedness of certain sublinear operators on the
weighted variable Lebesgue space. Note that the proof of multidimensional Hardy
type operator in weighted Lebesgue spaces with a variable exponent don't
contained any mistakes. But at the proving of the boundedness of certain
sublinear operators on the weighted variable Lebesgue space Georgian colleagues
discovered a small but significant error in this paper. This result is assigned
as Theorem 5 in noted paper. In other words, sufficient conditions for general
weights ensuring the validity of the two-weight strong type inequalities for
some sublinear operator was found. In this theorem the inequality (9) isn't
true. In this note we give the details of the correct argument. We presume that
the reader is familiar with the contents and notation of our original paper. At
the heart of our correction is the following Theorem which replaces Theorem 5.


title: The Gaia mission

abstract:
  Gaia is a very ambitious mission of the European Space Agency. At the heart
of Gaia lie the measurements of the positions, distances, space motions,
brightnesses and astrophysical parameters of stars, which represent fundamental
pillars of modern astronomical knowledge. We provide a brief description of the
Gaia mission with an emphasis on binary stars. In particular, we summarize
results of simulations, which estimate the number of binary stars to be
processed to several tens of millions. We also report on the catalogue release
scenarios. In the current proposal, the first results for binary stars will be
available in 2017 (for a launch in 2013).


title:
Near-Infrared Spectroscopy of SN2009ip's 2012 Brightening Reveals a
  Dusty Pre-Supernova Environment

abstract:
  We present low-resolution near-IR 0.8-2.5 um spectra of SN2009ip, taken
immediately before, during, and just after its rapid brightening in late
Sep/Oct 2012. The first epoch shows the same general spectral characteristics
as the later epochs (smooth continuum, narrow H and HeI emission lines), but
the IR continuum shape is substantially redder than the later epochs. The epoch
1 continuum can be approximated by reddening the peak-luminosity (epoch 3)
spectrum by E(B-V)=1.0 mag, but the blue color seen in visual-wavelength
spectra at the same time indicates that strong wavelength-dependent extinction
by circumstellar dust is not the correct explanation. Instead, we favor the
hypothesis that the redder color before the brightening arises from excess
emission from hot $\sim$2000 K circumstellar dust. The minimum radius (120 AU)
deduced from the dust temperature and observed luminosity of the transient,
combined with the observed expansion speed in the precursor outbursts of SN
2009ip, is consistent with an ejection at least 1.1 yr earlier. The mass of hot
dust indicated by the IR excess is 4x10$^{-7}$ Msun, although this is only a
lower limit since the near-IR data do not constrain the mass of cooler dust.
Thus, the observed pre-SN outbursts of this object were able to efficiently
form dust into which the SN ejecta and radiation now propagate. This is
consistent with the notion that the same pre-SN eruptions that generally give
rise to SNe IIn also give rise to the dust needed for their commonly observed
IR echoes. We also discuss some aspects of the IR line profiles, including HeI
10830.


title: An exact real-space renormalization method and applications

abstract:
  We present a numerical method based on real-space renormalization that
outputs the exact ground space of "frustration-free" Hamiltonians. The
complexity of our method is polynomial in the degeneracy of the ground spaces
of the Hamiltonians involved in the renormalization steps. We apply the method
to obtain the full ground spaces of two spin systems. The first system is a
spin-1/2 Heisenberg model with four-spin cyclic-exchange interactions defined
on a square lattice. In this case, we study finite lattices of up to 160 spins
and find a triplet ground state that differs from the singlet ground states
obtained in C.D. Batista and S. Trugman, Phys. Rev. Lett. 93, 217202 (2004). We
characterize such a triplet state as consisting of a triplon that propagates in
a background of fluctuating singlet dimers. The second system is a family of
spin-1/2 Heisenberg chains with uniaxial exchange anisotropy and next-nearest
neighbor interactions. In this case, the method finds a ground-space degeneracy
that scales quadratically with the system size and outputs the full ground
space efficiently. Our method can substantially outperform methods based on
exact diagonalization and is more efficient than other renormalization methods
when the ground-space degeneracy is large.


title:
Some Notes on the Use of the Windowed Fourier Transform for Spectral
  Analysis of Discretely Sampled Data

abstract:
  The properties of the Gabor and Morlet transforms are examined with respect
to the Fourier analysis of discretely sampled data. Forward and inverse
transform pairs based on a fixed window with uniform sampling of the frequency
axis can satisfy numerically the energy and reconstruction theorems; however,
transform pairs based on a variable window or nonuniform frequency sampling in
general do not. Instead of selecting the shape of the window as some function
of the central frequency, we propose constructing a single window with unit
energy from an arbitrary set of windows which is applied over the entire
frequency axis. By virtue of using a fixed window with uniform frequency
sampling, such a transform satisfies the energy and reconstruction theorems.
The shape of the window can be tailored to meet the requirements of the
investigator in terms of time/frequency resolution. The algorithm extends
naturally to the case of nonuniform signal sampling without modification beyond
identification of the Nyquist interval.


title:
Star-planet interactions and selection effects from planet detection
  methods

abstract:
  Planets may have effects on their host stars by tidal or magnetic
interaction. Such star-planet interactions are thought to enhance the activity
level of the host star. However, stellar activity also affects the sensitivity
of planet detection methods. Samples of planet-hosting stars which are
investigated for such star-planet interactions are therefore subject to strong
selection effects which need to be taken into account.


title: Stability of switched linear differential systems

abstract:
  We study the stability of switched systems where the dynamic modes are
described by systems of higher-order linear differential equations not
necessarily sharing the same state space. Concatenability of trajectories at
the switching instants is specified by gluing conditions, i.e. algebraic
conditions on the trajectories and their derivatives at the switching instant.
We provide sufficient conditions for stability based on LMIs for systems with
general gluing conditions. We also analyse the role of positive-realness in
providing sufficient polynomial-algebraic conditions for stability of two-modes
switched systems with special gluing conditions.


title: One-Class Support Measure Machines for Group Anomaly Detection

abstract:
  We propose one-class support measure machines (OCSMMs) for group anomaly
detection which aims at recognizing anomalous aggregate behaviors of data
points. The OCSMMs generalize well-known one-class support vector machines
(OCSVMs) to a space of probability measures. By formulating the problem as
quantile estimation on distributions, we can establish an interesting
connection to the OCSVMs and variable kernel density estimators (VKDEs) over
the input space on which the distributions are defined, bridging the gap
between large-margin methods and kernel density estimators. In particular, we
show that various types of VKDEs can be considered as solutions to a class of
regularization problems studied in this paper. Experiments on Sloan Digital Sky
Survey dataset and High Energy Particle Physics dataset demonstrate the
benefits of the proposed framework in real-world applications.


title:
A potential sterile neutrino search utilizing spectral distortion in a
  two-reactor/one-detector configuration

abstract:
  There is an observed deficit of about 6\% in the expected rate of
anti-neutrino interactions when averaging over many different reactor
experiments. While the significance of the deficit is low (98.6 \% CL), there
is speculation that a non-interacting "sterile" neutrino could be the cause. In
this paper we explore the possibility of a two-reactor/one-detector experiment
at intermediate distances (100-500 meters) to look for a sterile neutrino in
the mass range implied by this deficit. A method for probing $\Delta m^2$ phase
space is developed using interference patterns between two oscillated spectra
at different baselines. This method is used to investigate the potential
sensitivity of the Double Chooz experiment, which has a single Near Detector at
distances of 351 m and 465 m from two reactors of identical design. We conclude
that Double Chooz could investigate sterile neutrino in the $\Delta m^{2}$
range of 0.002 to 0.5 eV$^2$ over 5 years of near detector running.


title: A magnetic cycle of tau Bootis? The coronal and chromospheric view

abstract:
  Tau Bootis is a late F-type main sequence star orbited by a Hot Jupiter.
During the last years spectropolarimetric observations led to the hypothesis
that this star may host a global magnetic field that switches its polarity once
per year, indicating a very short activity cycle of only one year duration. In
our ongoing observational campaign, we have collected several X-ray
observations with XMM-Newton and optical spectra with TRES/FLWO in Arizona to
characterize tau Boo's corona and chromosphere over the course of the supposed
one-year cycle. Contrary to the spectropolarimetric reconstructions, our
observations do not show indications for a short activity cycle.


title: Polynomial Assignments

abstract:
  The concept of assignments was introduced in [GGK99] as a method for
extracting geometric information about group actions on manifolds from
combinatorial data encoded in the infinitesimal orbit-type stratification. In
this paper we will answer in the affirmative a question posed in [GGK99] by
showing that the equivariant cohomology ring of $M$ is to a large extent
determined by this data.


title: Splashing onset in dense suspension droplets

abstract:
  We investigate the impact of droplets of dense suspensions onto a solid
substrate. We show that a global hydrodynamic balance is unable to predict the
splash onset and propose to replace it by an energy balance at the level of the
particles in the suspension. We experimentally verify that the resulting,
particle-based Weber number gives a reliable, particle size and density
dependent splash onset criterion. We further show that the same argument also
explains why in bimodal systems smaller particles are more likely to escape
than larger ones.


title: Asymmetric coevolutionary voter dynamics

abstract:
  We consider a modification of the adaptive contact process which, interpreted
in the context of opinion dynamics, breaks the symmetry of the coevolutionary
voter model by assigning to each node type a different strategy to promote
consensus: orthodox opinion holders spread their opinion via social pressure
and rewire their connections following a segregationist strategy; heterodox
opinion holders adopt a proselytic strategy, converting their neighbors through
personal interactions, and relax to the orthodox opinion according to its
representation in the population. We give a full description of the phase
diagram of this asymmetric model, using the standard pair approximation
equations and assessing their performance by comparison with stochastic
simulations. We find that although global consensus is favored with regard to
the symmetric case, the asymmetric model also features an active phase. We
study the stochastic properties of the corresponding metastable state in
finite-size networks, discussing the applicability of the analytic
approximations developed for the coevolutionary voter model. We find that, in
contrast to the symmetric case, the final consensus state is predetermined by
the system's parameters and independent of initial conditions for sufficiently
large system sizes. We also find that rewiring always favors consensus, both by
significantly reducing convergence times and by changing their scaling with
system size.


title:
Structural Origins of Conductance Fluctuations in Gold-Thiolate
  Molecular Transport Junctions

abstract:
  We report detailed atomistic simulations combined with high-fidelity
conductance calculations to probe the structural origins of conductance
fluctuations in thermally evolving Au-benzene-1,4-dithiolate-Au junctions. We
compare the behavior of structurally ideal junctions (electrodes with flat
surfaces) to structurally realistic, experimentally representative junctions
resulting from break junction simulations. The enhanced mobility of metal atoms
in structurally realistic junctions results in significant changes to the
magnitude and origin of the conductance fluctuations. Fluctuations are larger
by a factor of 2-3 in realistic junctions compared to ideal junctions.
Moreover, in junctions with highly deformed electrodes, the conductance
fluctuations arise primarily from changes in the Au geometry, in contrast to
results for junctions with non-deformed electrodes, where the conductance
fluctuations are dominated by changes in the molecule geometry. These results
provide important guidance to experimentalists developing strategies to control
molecular conductance for device applications, and also to theoreticians
invoking simplified structural models of junctions to predict their behavior.


title:
Expanded Iron UTA spectra -- probing the thermal stability limits in AGN
  clouds

abstract:
  The Fe unresolved transition array (UTAs) produce prominent features in the
15-17?A wavelength range in the spectra of Active Galactic Nuclei (AGN). Here
we present new calculations of the energies and oscillator strengths of inner-
shell lines from Fe XIV, Fe XV, and Fe XVI. These are crucial ions since they
are dominant at inflection points in the gas thermal stability curve, and UTA
excitation followed by autoionization is an important ionization mechanism for
these species. We incorporate these, and data reported in previous papers, into
the plasma simulation code Cloudy. This updated physics is subsequently
employed to reconsider the thermally stable phases in absorbing media in Active
Galactic Nuclei. We show how the absorption profile of the Fe XIV UTA depends
on density, due to the changing populations of levels within the ground
configuration.


title: Constraints on physics of neutron stars from X-ray observations

abstract:
  I summarize some constraints on the physics of neutron stars arising from
X-ray observations of the surfaces of neutron stars, focusing on using models
of low-magnetic-field neutron star atmospheres to interpret their X-ray
spectra. I discuss observations of spectral lines, pulsation profiles, X-ray
bursts, radius measurements of transiently accreting neutron stars in
quiescence, crust and core cooling measurements of transiently accreting
neutron stars, and cooling of young neutron stars. These observations have
constrained the neutron star mass and radius (and thus the internal
composition, and dense matter equation of state), the superfluidity and
neutrino emissivity properties of the core, and the composition and superfluid
state of the crust.


title: Estimating $\hat{q}$ in Quenched Lattice SU(2) Gauge Theory

abstract:
  The propagation of a virtual quark in a thermal medium is considered. The
non-perturbative jet transport coefficient $\hat{q}$ is estimated in quark less
SU(2) lattice gauge theory. The light like correlator which defines $\hat{q}$,
defined in the regime where the jet has small virtuality compared to its
energy, is analytically related to a series of local operators in the deep
Euclidean region, where the jet's virtuality is of the same order as its
energy. It is demonstrated that in this region, for temperatures in the range
of T=400-600 MeV, and for jet energies above 20 GeV, the leading term in the
series is dominant over the next-to-leading term and thus yields an estimate of
the value of $\hat{q}$. In these proceedings we discuss the details of the
numerical calculation.


title:
Honeycomb lattice of graphite probed by scanning tunneling microscopy
  with a carbon nanotube tip

abstract:
  A carbon nanotube (CNT) tip was fabricated at the apex of an etched tungsten
wire by chemical vapor deposition and used for scanning tunneling microscopy.
The honeycomb lattice of graphite in the STM images was resolved with a CNT tip
at T=79 K. The superior spatial resolution originating from the p orbitals of a
CNT is responsible for the image of the honeycomb lattice of graphite in the
STM images. The CNT tips are useful to image samples whose lattice constants
are small and to get orbital information in samples with orbital ordering due
to their superior spatial resolution with the sharp p orbitals.


title:
The Stellar Masses of Disk Galaxies and the Calibration of Color-Mass to
  Light Ratio Relations

abstract:
  We present new Spitzer 3.6 micron observations of a sample of disk galaxies
spanning over 10 magnitudes in luminosity and ranging in gas fraction from ~10%
to over 90%. We use these data to test population synthesis prescriptions for
computing stellar mass. Many commonly employed models fail to provide
self-consistent stellar masses in the sense that the stellar mass estimated
from the optical luminosity typically exceeds that estimated from the
near-infrared (NIR) luminosity. This problem is present in models both with and
without TP-AGB stars, but is more severe in the former. Self-consistency can be
achieved if NIR mass-to-light ratios are approximately constant with a mean
value near 0.5 Msun/Lsun at 3.6 microns. We use the Baryonic Tully-Fisher
relation calibrated by gas rich galaxies to provide an independent estimate of
the color-mass to light ratio relation. This approach also suggests that the
typical 3.6 micron mass-to-light ratio is 0.5 (0.65 in the K band) for
rotationally supported galaxies. These values are consistent with a Kroupa IMF.


title: Betelgeuse and the red supergiants

abstract:
  Betelgeuse is one of the most magnificent stars in the sky, and one of the
nearest red supergiants. Astronomers gathered in Paris in the Autumn of 2012 to
decide what we know about its structure, behaviour, and past and future
evolution, and how to place this in the general context of the class of red
supergiants. Here I reflect on the discussions and propose a synthesis of the
presented evidence. I believe that, in those four days, we have achieved to
solve a few riddles.


title: Strong mixing measures for linear operators and frequent hypercyclicity

abstract:
  We construct strongly mixing invariant measures with full support for
operators on F-spaces which satisfy the Frequent Hypercyclicity Criterion. For
unilateral backward shifts on sequence spaces, a slight modification shows that
one can even obtain exact invariant measures.


title: Clubs-based Particle Swarm Optimization

abstract:
  This paper introduces a new dynamic neighborhood network for particle swarm
optimization. In the proposed Clubs-based Particle Swarm Optimization (C-PSO)
algorithm, each particle initially joins a default number of what we call
'clubs'. Each particle is affected by its own experience and the experience of
the best performing member of the clubs it is a member of. Clubs membership is
dynamic, where the worst performing particles socialize more by joining more
clubs to learn from other particles and the best performing particles are made
to socialize less by leaving clubs to reduce their strong influence on other
members. Particles return gradually to default membership level when they stop
showing extreme performance. Inertia weights of swarm members are made random
within a predefined range. This proposed dynamic neighborhood algorithm is
compared with other two algorithms having static neighborhood topologies on a
set of classic benchmark problems. The results showed superior performance for
C-PSO regarding escaping local optima and convergence speed.


title:
Multi-Dimensional Double Detonation of Sub-Chandrasekhar Mass White
  Dwarfs

abstract:
  Using 2D and 3D simulation, we study the "robustness" of the double
detonation scenario for Type Ia supernovae, in which a detonation in the helium
shell of a carbon-oxygen white dwarf induces a secondary detonation in the
underlying core. We find that a helium detonation cannot easily descend into
the core unless it commences (artificially) well above the hottest layer
calculated for the helium shell in current presupernova models. Compressional
waves induced by the sliding helium detonation, however, robustly generate hot
spots which trigger a detonation in the core. Our simulations show that this is
true even for non-axisymmetric initial conditions. If the helium is ignited at
multiple points, the internal waves can pass through one another or be
reflected, but this added complexity does not defeat the generation of the hot
spot. The ignition of very low-mass helium shells depends on whether a
thermonuclear runaway can simultaneously commence in a sufficiently large
region.


title: Some integer formula-encodings and related algorithms

abstract:
  We investigate the special class of formulas made up of arbitrary but finite
com- binations of addition, multiplication, and exponentiation gates. The
inputs to these formulas are restricted to the integral unit 1. In connection
with such formulas, we describe two essen- tially distinct families of
canonical formula-encodings for integers, respectively deduced from the decimal
encoding and the fundamental theorem of arithmetic. Our main contribution is
the de- tailed description of two algorithms which efficiently determine the
canonical formula-encodings associated with relatively large sets of
consecutive integers.


title: Robust Sensitivity Analysis for Stochastic Systems

abstract:
  We study a worst-case approach to measure the sensitivity to model
misspecification in the performance analysis of stochastic systems. The
situation of interest is when only minimal parametric information is available
on the form of the true model. Under this setting, we post optimization
programs that compute the worst-case performance measures, subject to
constraints on the amount of model misspecification measured by
Kullback-Leibler (KL) divergence. Our main contribution is the development of
infinitesimal approximations for these programs, resulting in asymptotic
expansions of their optimal values in terms of the divergence. The coefficients
of these expansions can be computed via simulation, and are mathematically
derived from the representation of the worst-case models as changes of measure
that satisfy a well-defined class of functional fixed point equations.


title: Strong mixing measures for $C_0$-semigroups

abstract:
  Our purpose is to obtain a very effective and general method to prove that
certain $C_0$-semigroups admit invariant strongly mixing measures. More
precisely, we show that the Frequent Hypercyclicity Criterion for
$C_0$-semigroups ensures the existence of invariant mixing measures with full
support. We will several examples, that range from birth-and-death models to
the Black-Scholes equation, which illustrate these results.


title: Efficient long division via Montgomery multiply

abstract:
  We present a novel right-to-left long division algorithm based on the
Montgomery modular multiply, consisting of separate highly efficient loops with
simply carry structure for computing first the remainder (x mod q) and then the
quotient floor(x/q). These loops are ideally suited for the case where x
occupies many more machine words than the divide modulus q, and are strictly
linear time in the "bitsize ratio" lg(x)/lg(q). For the paradigmatic
performance test of multiword dividend and single 64-bit-word divisor,
exploitation of the inherent data-parallelism of the algorithm effectively
mitigates the long latency of hardware integer MUL operations, as a result of
which we are able to achieve respective costs for remainder-only and full-DIV
(remainder and quotient) of 6 and 12.5 cycles per dividend word on the Intel
Core 2 implementation of the x86_64 architecture, in single-threaded execution
mode. We further describe a simple "bit-doubling modular inversion" scheme,
which allows the entire iterative computation of the mod-inverse required by
the Montgomery multiply at arbitrarily large precision to be performed with
cost less than that of a single Newtonian iteration performed at the full
precision of the final result. We also show how the Montgomery-multiply-based
powering can be efficiently used in Mersenne and Fermat-number trial
factorization via direct computation of a modular inverse power of 2, without
any need for explicit radix-mod scalings.


title: Well-Mixed Dark Matter and the Higgs

abstract:
  The breaking of electroweak symmetry through renormalization group flow in
models that have MSSM spectra is found to produce "well-mixed" neutralino dark
matter with a relic density consistent with the WMAP data and elastic
scattering cross section with nuclei consistent with current limits from direct
dark matter searches. These models predict a Higgs boson mass in the range
(125-126) GeV. Well-mixed neutralino dark matter is predominantly bino-like,
but has significant Higgsino and wino content, each with fractions of
comparable size. With a ~1 TeV gluino mass and sizable neutralino-nucleon
scattering cross sections, natural models will be fully tested by both the LHC
and future dark matter direct detection experiments.


title:
Micropropulsion and microrheology in complex fluids via symmetry
  breaking

abstract:
  Many biological fluids have polymeric microstructures and display
non-Newtonian rheology. We take advantage of such nonlinear fluid behavior and
combine it with geometrical symmetry-breaking to design a novel small-scale
propeller able to move only in complex fluids. Its propulsion characteristics
are explored numerically in an Oldroyd-B fluid for finite Deborah numbers while
the small Deborah number limit is investigated analytically using a
second-order fluid model. We then derive expressions relating the propulsion
speed to the rheological properties of the complex fluid, allowing thus to
infer the normal stress coefficients in the fluid from the locomotion of the
propeller. Our simple mechanism can therefore be used either as a non-Newtonian
micro-propeller or as a micro-rheometer.


title: Structure of 8B from elastic and inelastic 7Be+p scattering

abstract:
  Motivation: Detailed experimental knowledge of the level structure of light
weakly bound nuclei is necessary to guide the development of new theoretical
approaches that combine nuclear structure with reaction dynamics.
  Purpose: The resonant structure of 8B is studied in this work.
  Method: Excitation functions for elastic and inelastic 7Be+p scattering were
measured using a 7Be rare isotope beam. Excitation energies ranging between 1.6
and 3.4 MeV were investigated. An R-matrix analysis of the excitation functions
was performed.
  Results: New low-lying resonances at 1.9, 2.5, and 3.3 MeV in 8B are reported
with spin-parity assignment 0+, 2+, and 1+, respectively. Comparison to the
Time Dependent Continuum Shell (TDCSM) model and ab initio no-core shell
model/resonating-group method (NCSM/RGM) calculations is performed. This work
is a more detailed analysis of the data first published as a Rapid
Communication. [J.P. Mitchell, et al, Phys. Rev. C 82, 011601(R) (2010)]
  Conclusions: Identification of the 0+, 2+, 1+ states that were predicted by
some models at relatively low energy but never observed experimentally is an
important step toward understanding the structure of 8B. Their identification
was aided by having both elastic and inelastic scattering data. Direct
comparison of the cross sections and phase shifts predicted by the TDCSM and ab
initio No Core Shell Model coupled with the resonating group method is of
particular interest and provides a good test for these theoretical approaches.


title: Top-flavored dark matter and the forward-backward asymmetry

abstract:
  We propose a simple model where dark matter (DM) carries top flavor and
couples to the Standard Model through the top quark within a framework of
minimal flavor violation (MFV). Top-flavored DM can explain the anomalous top
forward-backward asymmetry observed at the Tevatron, while remaining consistent
with other top observables at colliders. By virtue of its large coupling to
top, DM acquires a sizable loop coupling to the Z boson, and the relic density
is set by annihilation through the Z. We also discuss contraints from current
direct detection searches, emphasizing the role of spin-dependent searches to
probe this scenario.


title:
Production of a rubidium Bose-Einstein condensate in a hybrid trap with
  light induced atom desorption

abstract:
  We report on the production of a rubidium Bose-Einstein condensate in a
simplified vacuum apparatus. Magneto-optical traps with large numbers and
ultra-high vacuum for moderately long conservative trap lifetimes of 16 seconds
are sequentially obtained with light induced rapid atomic vapor pressure
modulation. Subsequent evaporative cooling is carried out in two stages in a
hybrid magnetic quadrupole plus optical dipole trap. High evaporation
efficiencies are observed in both stages and $^{87}$Rb BECs with more than
10$^5$ atoms can be reliably produced with total evaporation time of only 9.5
seconds.


title: Observation of Feshbach resonances between ultracold Na and Rb atoms

abstract:
  We have successfully prepared an optically trapped ultracold mixture of
$^{23}$Na and $^{87}$Rb atoms and studied their interspecies Feshbach
resonances. Using two different spin combinations, several s-wave and p-wave
resonances are identified by observing a high inelastic loss and a temperature
rising for both species near resonant magnetic field values. The two s-wave
resonances observed below 500 G between atoms in the lowest energy level are
possible candidates for Feshbach molecule association. Our results are well
characterized by a coupled-channel model and are used refining the ground state
interaction potentials between $^{23}$Na and $^{87}$Rb. This work opens up the
prospect for preparing ultracold ensembles of ground-state bosonic NaRb
molecules which are chemically stable and can provide strong dipolar
interactions.


title:
Energy Positivity, Non-Renormalization, and Holomorphy in
  Lorentz-Violating Supersymmetric Theories

abstract:
  This paper shows that the positive-energy and non-renormalization theorems of
traditional supersymmetry survive the addition of Lorentz violating
interactions. The Lorentz-violating coupling constants in theories using the
construction of Berger and Kostelecky must obey certain constraints in order to
preserve the positive energy theorem. Seiberg's holomorphic arguments are used
to prove that the superpotential remains non-renormalized (perturbatively) in
the presence of Lorentz-violating interactions of the Berger-Kostelecky type.
We briefly comment on Lorentz-violating theories of the type constructed by
Nibbelink and Pospelov to note that holomorphy arguments offer elegant proofs
of many non-renormalization results, some known by other arguments, some new.


title:
Nature of the Roberge-Weiss transition end points in two-flavor lattice
  QCD with Wilson quarks

abstract:
  We make simulations with 2 flavor Wilson fermions to investigate the nature
of the end points of Roberge-Weiss (RW) first order phase transition lines. The
simulations are carried out at 9 values of the hopping parameter $\kappa$
ranging from 0.155 to 0.198 on different lattice spatial volume. The Binder
cumulants, susceptibilities and reweighted distributions of the imaginary part
of Polyakov loop are employed to determine the nature of the end points of RW
transition lines. The simulations show that the RW end points are of first
order at the values of $\kappa$ in our simulations.


title: Excursion Set Theory for Correlated Random Walks

abstract:
  We present a new method to compute the first crossing distribution in
excursion set theory for the case of correlated random walks. We use a
combination of the path integral formalism of Maggiore & Riotto, and the
integral equation solution of Zhang & Hui, and Benson et al. to find a
numerically robust and convenient algorithm to derive the first crossing
distribution in terms of a perturbative expansion around the limit of an
uncorrelated random walk. We apply this methodology to the specific case of a
Gaussian random density field filtered with a Gaussian smoothing function. By
comparing our solutions to results from Monte Carlo calculations of the first
crossing distribution we demonstrate that our method accurate for power spectra
$P(k)\propto k^n$ for $n=1$, becoming less accurate for smaller values of $n$.
It is therefore complementary to the method of Musso & Sheth, which will
therefore be more useful for standard $\Lambda$CDM power spectra. Our approach
is quite general, and can be adapted to other smoothing functions, and also to
non-Gaussian density fields.


title:
The NGC 5253 star cluster system. I. Standard modelling and
  infrared-excess sources

abstract:
  Using high-resolution Hubble Space Telescope data, we reexamine the
fundamental properties (ages, masses and extinction values) of the rich star
cluster population in the dwarf starburst galaxy NGC 5253. The gain in
resolution compared to previous studies is of order a factor of two in both
spatial dimensions, while our accessible wavelength range transcends previous
studies by incorporation of both near-ultraviolet and near-infrared (IR)
passbands. We apply spectral synthesis treatments based on two different simple
stellar population model suites to our set of medium-, broad-band and H-alpha
images to gain an improved physical understanding of the IR-excess flux found
for a subset of young clusters (30 of 149). With the caveat that our models are
based on fully sampled stellar mass functions, the NGC 5253 cluster population
is dominated by a significant number of relatively low-mass (M_cl <= a few 10^4
Msun) objects with ages ranging from a few x 10^6 to a few x 10^7 yr, which is
in excellent agreement with the starburst age of the host galaxy. The IR-excess
clusters are almost all found in this young age range and have masses of up to
a few x 10^4 Msun. The IR excess in the relatively low-mass NGC 5253 clusters
is most likely caused by a combination of stochastic sampling effects and
colour variations due to the presence of either luminous red or
pre-main-sequence stars. We also find a small number of intermediate-age (~ 1
Gyr-old), ~10^5 Msun clusters, as well as up to a dozen massive, ~10 Gyr-old
globular clusters. Their presence supports the notion that NGC 5253 is a very
active galaxy that has undergone multiple episodes of star cluster formation.


title: Learning Hash Functions Using Column Generation

abstract:
  Fast nearest neighbor searching is becoming an increasingly important tool in
solving many large-scale problems. Recently a number of approaches to learning
data-dependent hash functions have been developed. In this work, we propose a
column generation based method for learning data-dependent hash functions on
the basis of proximity comparison information. Given a set of triplets that
encode the pairwise proximity comparison information, our method learns hash
functions that preserve the relative comparison relationships in the data as
well as possible within the large-margin learning framework. The learning
procedure is implemented using column generation and hence is named CGHash. At
each iteration of the column generation procedure, the best hash function is
selected. Unlike most other hashing methods, our method generalizes to new data
points naturally; and has a training objective which is convex, thus ensuring
that the global optimum can be identified. Experiments demonstrate that the
proposed method learns compact binary codes and that its retrieval performance
compares favorably with state-of-the-art methods when tested on a few benchmark
datasets.


title: Bicategorical fibration structures and stacks

abstract:
  The familiar construction of categories of fractions, due to Gabriel and
Zisman, allows one to invert a class W of arrows in a category in a universal
way. Similarly, bicategories of fractions allow one to invert a collection of
arrows in a bicategory. In this case the arrows are inverted in the sense that
they are made into equivalences. As with categories of fractions, bicategories
of fractions suffer from the defect that they need not be locally small even
when the bicategory in which W lives is locally small. Similarly, in the case
where W is a class of arrows in a 2-category, the bicategory of fractions will
not in general be a 2-category.
  In this paper we introduce two notions ---systems of fibrant objects and
fibration systems--- which will allow us to associate to a bicategory B a
homotopy bicategory Ho(B) in such a way that Ho(B) is the universal way to
invert weak equivalences in B. This construction resolves both of the
difficulties with bicategories of fractions mentioned above. We also describe a
fibration system on the 2-category of prestacks on a site and prove that the
resulting homotopy bicategory is the 2-category of stacks. Further examples
considered include algebraic, differentiable and topological stacks.


title: Matrix Completion via Max-Norm Constrained Optimization

abstract:
  Matrix completion has been well studied under the uniform sampling model and
the trace-norm regularized methods perform well both theoretically and
numerically in such a setting. However, the uniform sampling model is
unrealistic for a range of applications and the standard trace-norm relaxation
can behave very poorly when the underlying sampling scheme is non-uniform.
  In this paper we propose and analyze a max-norm constrained empirical risk
minimization method for noisy matrix completion under a general sampling model.
The optimal rate of convergence is established under the Frobenius norm loss in
the context of approximately low-rank matrix reconstruction. It is shown that
the max-norm constrained method is minimax rate-optimal and yields a unified
and robust approximate recovery guarantee, with respect to the sampling
distributions. The computational effectiveness of this method is also
discussed, based on first-order algorithms for solving convex optimizations
involving max-norm regularization.


title: Tetraquark Mesons in Large $N$ Quantum Chromodynamics

abstract:
  It is argued that exotic mesons consisting of two quarks and two antiquarks
are not ruled out in quantum chromodynamics with a large number $N$ of colors,
as generally thought. They can come in two varieties: short-lived tetraquarks
with decay rates proportional to $N$, which would be unobservable if $N$ were
sufficiently large, and long-lived tetraquarks with decay rates proportional to
1/N. The $f_0(500)$ and $f_0(980)$ may be examples of these two varieties of
exotic mesons.


title:
Entropic effects in the self-assembly of open lattices from patchy
  particles

abstract:
  Open lattices are characterized by low volume-fraction arrangements of
building blocks, low coordination number, and open spaces between building
blocks. The self-assembly of these lattices faces the challenge of mechanical
instability due to their open structures. We theoretically investigate the
stabilizing effects of entropy in the self-assembly of open lattices from
patchy particles. A preliminary account of these findings and their comparison
to experiment was presented recently [X. Mao, Q. Chen, S. Granick, \textit{Nat.
Mater.}, \textbf{12}, 217 (2013)]. We found that rotational entropy of patchy
particles can provide mechanical stability to open lattices, whereas
vibrational entropy of patchy particles can lower the free energy of open
lattices and thus enables the selection of open lattices verses close-packed
lattices which have the same potential energy. These effects open the door to
significant simplifications of possible future designs of patchy-particles for
open-lattice self-assembly.


title:
Network-based stochastic competitive learning approach to disambiguation
  in collaborative networks

abstract:
  Many patterns have been uncovered in complex systems through the application
of concepts and methodologies of complex networks. Unfortunately, the validity
and accuracy of the unveiled patterns are strongly dependent on the amount of
unavoidable noise pervading the data, such as the presence of homonymous
individuals in social networks. In the current paper, we investigate the
problem of name disambiguation in collaborative networks, a task that plays a
fundamental role on a myriad of scientific contexts. In special, we use an
unsupervised technique which relies on a particle competition mechanism in a
networked environment to detect the clusters. It has been shown that, in this
kind of environment, the learning process can be improved because the network
representation of data can capture topological features of the input data set.
Specifically, in the proposed disambiguating model, a set of particles is
randomly spawned into the nodes constituting the network. As time progresses,
the particles employ a movement strategy composed of a probabilistic convex
mixture of random and preferential walking policies. In the former, the walking
rule exclusively depends on the topology of the network and is responsible for
the exploratory behavior of the particles. In the latter, the walking rule
depends both on the topology and the domination levels that the particles
impose on the neighboring nodes. This type of behavior compels the particles to
perform a defensive strategy, because it will force them to revisit nodes that
are already dominated by them, rather than exploring rival territories.
Computer simulations conducted on the networks extracted from the arXiv
repository of preprint papers and also from other databases reveal the
effectiveness of the model, which turned out to be more accurate than
traditional clustering methods.


title:
Calibrating 100 Years of Polar Faculae Measurements: Implications for
  the Evolution of the Heliospheric Magnetic Field

abstract:
  Although the Sun's polar magnetic fields are thought to provide important
clues for understanding the 11-year sunspot cycle, including the observed
variations of its amplitude and period, the current database of high-quality
polar-field measurements spans relatively few sunspot cycles. In this paper we
address this deficiency by consolidating Mount Wilson Observatory polar faculae
data from four data reduction campaigns, validating it through a comparison
with facular data counted automatically from MDI intensitygrams, and
calibrating it against polar field measurements taken by the Wilcox Solar
Observatory and average polar field and total polar flux calculated using MDI
line-of-sight magnetograms. Our results show that the consolidated polar
facular measurements are in excellent agreement with both polar field and polar
flux estimates, making them an ideal proxy to study the evolution of the polar
magnetic field. Additionally, we combine this database with sunspot area
measurements to study the role of the polar magnetic flux in the evolution of
the heliospheric magnetic field (HMF). We find that there is a strong
correlation between HMF and polar flux at solar minimum and that, taken
together, polar flux and sunspot area are better at explaining the evolution of
the HMF during the last century than sunspot area alone.


title: Secure Distance Bounding Verification using Physical-Channel Properties

abstract:
  We consider the problem of distance bounding verification (DBV), where a
proving party claims a distance and a verifying party ensures that the prover
is within the claimed distance. Current approaches to "secure" distance
estimation use signal's time of flight, which requires the verifier to have an
accurate clock. We study secure DBV using physical channel properties as an
alternative to time measurement. We consider a signal propagation environment
that attenuates signal as a function of distance, and then corrupts it by an
additive noise.
  We consider three attacking scenarios against DBV, namely distance fraud
(DFA), mafia fraud (MFA) and terrorist fraud (TFA) attacks. We show it is
possible to construct efficient DBV protocols with DFA and MFA security, even
against an unbounded adversary; on the other hand, it is impossible to design
TFA-secure protocols without time measurement, even with a
computationally-bounded adversary. We however provide a TFA-secure construction
under the condition that the adversary's communication capability is limited to
the bounded retrieval model (BRM). We use numerical analysis to examine the
communication complexity of the introduced DBV protocols. We discuss our
results and give directions for future research.


title:
Probing the statistical properties of unknown texts: application to the
  Voynich Manuscript

abstract:
  While the use of statistical physics methods to analyze large corpora has
been useful to unveil many patterns in texts, no comprehensive investigation
has been performed investigating the properties of statistical measurements
across different languages and texts. In this study we propose a framework that
aims at determining if a text is compatible with a natural language and which
languages are closest to it, without any knowledge of the meaning of the words.
The approach is based on three types of statistical measurements, i.e. obtained
from first-order statistics of word properties in a text, from the topology of
complex networks representing text, and from intermittency concepts where text
is treated as a time series. Comparative experiments were performed with the
New Testament in 15 different languages and with distinct books in English and
Portuguese in order to quantify the dependency of the different measurements on
the language and on the story being told in the book. The metrics found to be
informative in distinguishing real texts from their shuffled versions include
assortativity, degree and selectivity of words. As an illustration, we analyze
an undeciphered medieval manuscript known as the Voynich Manuscript. We show
that it is mostly compatible with natural languages and incompatible with
random texts. We also obtain candidates for key-words of the Voynich Manuscript
which could be helpful in the effort of deciphering it. Because we were able to
identify statistical measurements that are more dependent on the syntax than on
the semantics, the framework may also serve for text analysis in
language-dependent applications.


title: Localized atomic basis set in the projector augmented wave method

abstract:
  We present an implementation of localized atomic orbital basis sets in the
projector augmented wave (PAW) formalism within the density functional theory
(DFT). The implementation in the real-space GPAW code provides a complementary
basis set to the accurate but computationally more demanding grid
representation. The possibility to switch seamlessly between the two
representations implies that simulations employing the local basis can be fine
tuned at the end of the calculation by switching to the grid, thereby combining
the strength of the two representations for optimal performance. The
implementation is tested by calculating atomization energies and equilibrium
bulk properties of a variety of molecules and solids, comparing to the grid
results. Finally, it is demonstrated how a grid-quality structure optimization
can be performed with significantly reduced computational effort by switching
between the grid and basis representations.


title:
The unusual minimum of sunspot cycle 23 a consequence of Sun's
  meridional plasma flow variations

abstract:
  Direct observations over the past four centuries show that the number of
sunspots observed on the Sun's surface vary periodically, going through
successive maxima and minima. Following sunspot cycle 23, the Sun went into a
prolonged minimum characterized by a very weak polar magnetic field and an
unusually large number of days without sunspots. Sunspots are strongly
magnetized regions and are generated by a dynamo mechanism which recreates the
solar polar field mediated via plasma flows. Here we report results from
kinematic dynamo simulations which demonstrate that a fast meridional flow in
the early half of a cycle, followed by a slower flow in the latter half,
reproduces both the characteristics of the minimum of sunspot cycle 23 - a
large number of spotless days and a relatively weak polar field. Our model
predicts that, in general, very deep minima are associated with weak polar
fields. Sunspots govern the solar radiative energy and radio flux, and in
conjunction with the polar field, modulate the solar wind, heliospheric open
flux and consequently cosmic ray flux at Earth; our results therefore provide a
causal link between solar internal dynamics and the atypical values of these
heliospheric forcing parameters during the recently concluded solar minimum.


title:
Structure-semantics interplay in complex networks and its effects on the
  predictability of similarity in texts

abstract:
  There are different ways to define similarity for grouping similar texts into
clusters, as the concept of similarity may depend on the purpose of the task.
For instance, in topic extraction similar texts mean those within the same
semantic field, whereas in author recognition stylistic features should be
considered. In this study, we introduce ways to classify texts employing
concepts of complex networks, which may be able to capture syntactic, semantic
and even pragmatic features. The interplay between the various metrics of the
complex networks is analyzed with three applications, namely identification of
machine translation (MT) systems, evaluation of quality of machine translated
texts and authorship recognition. We shall show that topological features of
the networks representing texts can enhance the ability to identify MT systems
in particular cases. For evaluating the quality of MT texts, on the other hand,
high correlation was obtained with methods capable of capturing the semantics.
This was expected because the golden standards used are themselves based on
word co-occurrence. Notwithstanding, the Katz similarity, which involves
semantic and structure in the comparison of texts, achieved the highest
correlation with the NIST measurement, indicating that in some cases the
combination of both approaches can improve the ability to quantify quality in
MT. In authorship recognition, again the topological features were relevant in
some contexts, though for the books and authors analyzed good results were
obtained with semantic features as well. Because hybrid approaches encompassing
semantic and topological features have not been extensively used, we believe
that the methodology proposed here may be useful to enhance text classification
considerably, as it combines well-established strategies.


title:
A Review On Securing Distributed Systems Using Symmetric Key
  Cryptography

abstract:
  This review is aimed to evaluate the importance of Symmetric Key Cryptography
for Security in Distributed Systems. Businesses around the world as well as
research and other such areas rely heavily on distributed systems these days.
Hence, security is also a major concern due to the openness of the system. Out
of the various available security measures, we, in this paper, concentrate in
general on the symmetric key cryptographic technique. We review two widely used
and popular symmetric key cryptographic algorithms, viz. DES and AES. These two
algorithms are evaluated on the parameters such as key size, block size, number
of iterations, etc.


title:
Two-band effect on the vortex dynamics and critical current density in
  an anisotropic MgB$_2$ thin film

abstract:
  We report the influence of intrinsic superconducting parameters on the vortex
dynamics and the critical current densities of a MgB$_2$ thin film. The small
magnetic penetration depth of \lambda = 50 nm at T=4 K is related to a clean
\pi-band, and transport and magnetization data show an upper critical field
similar to those reported in clean single crystals. We find a high self-field
critical current density Jc, which is strongly reduced with applied magnetic
field, and attribute this to suppression of the superconductivity in the
\pi-band. The temperature dependence of the creep rate S(T) at low magnetic
field can be explained by a simple Anderson-Kim mechanism. The system shows
high pinning energies at low field that are strongly suppressed by high field,
which is consistent with a two-band contribution.


title: Transformations of Matrix Structures Work Again

abstract:
  In 1989 we proposed to employ Vandermonde and Hankel multipliers to transform
into each other the matrix structures of Toeplitz, Hankel, Vandermonde and
Cauchy types as a means of extending any successful algorithm for the inversion
of matrices having one of these structures to inverting the matrices with the
structures of the three other types. Surprising power of this approach has been
demonstrated in a number of works, which culminated in ingeneous numerically
stable algorithms that approximated the solution of a nonsingular Toeplitz
linear system in nearly linear (versus previuosly cubic) arithmetic time. We
first revisit this powerful method, covering it comprehensively, and then
specialize it to yield a similar acceleration of the known algorithms for
computations with matrices having structures of Vandermonde or Cauchy types. In
particular we arrive at numerically stable approximate multipoint polynomial
evaluation and interpolation in nearly linear arithmetic time.


title: Classification and Analysis of Mean Curvature Flow Self-Shrinkers

abstract:
  We investigate Mean Curvature Flow self-shrinking hypersurfaces with
polynomial growth. It is known that such self shrinkers are unstable. We focus
mostly on self-shrinkers of the form $\mathbb S^k\times\R^{n-k}\subset
\R^{n+1}$. We use a connection between the stability operator and the quantum
harmonic oscillator Hamiltonian to find all eigenvalues and eigenfunctions of
the stability operator on these self-shrinkers. We also show self-shrinkers of
this form have lower index than all other complete self-shrinking
hypersurfaces. In particular, they have finite index. This implies that the
ends of such self shrinkers must be stable. We look for the largest stable
regions of these self shrinkers.


title: Landau-Lifshitz theory of single susceptibility Maxwell equations

abstract:
  The conflicting arguments given in the discussion forum of Metamaterials 2011
on the possible forms of macroscopic Maxwell equations are lead to a
convergence by noting the relationship among the employed material variables
for each scheme. The three schemes by Chipouline et al. using (A) standard
$\Vec{P}$ and $\Vec{M}$ (Casimir form), (B) generalized electric polarization
$\Vec{P}_{LL}$ (Landau-Lifshitz form), (C) generalized magnetic polarization
$\Vec{M}_{A}$ (Anapole form) are compared with (D) the present author's scheme
using standard current density $\Vec{J}$. From the reversible relations among
the transverse components of these vectors, one can easily rewrite one scheme
into another. The scheme (D), the only one among the four providing the
first-principles expressions of susceptibility and also leading to a
non-phenomenological Casimir form in terms of the four generalized
susceptibilities between $\{\Vec{P},\Vec{M}\}$ and $\{\Vec{E},\Vec{B}\}$, is
concluded to be a more natural form than (B) and (C) as a single susceptibility
theory.


title: Audit Games

abstract:
  Effective enforcement of laws and policies requires expending resources to
prevent and detect offenders, as well as appropriate punishment schemes to
deter violators. In particular, enforcement of privacy laws and policies in
modern organizations that hold large volumes of personal information (e.g.,
hospitals, banks, and Web services providers) relies heavily on internal audit
mechanisms. We study economic considerations in the design of these mechanisms,
focusing in particular on effective resource allocation and appropriate
punishment schemes. We present an audit game model that is a natural
generalization of a standard security game model for resource allocation with
an additional punishment parameter. Computing the Stackelberg equilibrium for
this game is challenging because it involves solving an optimization problem
with non-convex quadratic constraints. We present an additive FPTAS that
efficiently computes a solution that is arbitrarily close to the optimal
solution.


title:
Signs of atmospheric inhomogeneities in cool stars from 1D-NLTE analysis
  of iron lines

abstract:
  For the well studied halo star HD 122563 and the four stars in the globular
cluster NGC 6397, we determine NLTE abundances of iron using classical
plane-parallel model atmospheres. Each star reveals a discrepancy in abundances
between the Fe I lines arising from the ground state and the other Fe I lines,
in qualitative agreement with the 3D-LTE line formation predictions, however,
the magnitude of the observed effect is a factor of 2 smaller compared with the
predicted one. When ignoring the Fe I low-excitation lines, the NLTE abundances
from the two ionization stages, Fe I and Fe II, are consistent in each
investigated star. For the subgiants in NGC 6397, this is only true when using
the cooler effective temperature scale of Alonso et al. (1999). We also present
full 3D-LTE line formation calculations for some selected iron lines in the
solar and metal-poor 4480/2/-3 models and NLTE calculations with the
corresponding spatial and temporal average <3D> models. The use of the <3D>
models is justified only for particular Fe I lines in particular physical
conditions. Our NLTE calculations reproduce well the centre-to-limb variation
of the solar Fe I 7780 A line, but they are unsuccessful for Fe I 6151 A. The
metal-poor <3D> model was found to be adequite for the strong Fe I 5166 A (Eexc
= 0) line, but inadequite in all other investigated cases.


title:
High Performance Molybdenum Disulfide Amorphous Silicon Heterojunction
  Photodetector

abstract:
  One important use of layered semiconductors such as molybdenum disulfide
(MoS2) could be in making novel heterojunction devices leading to
functionalities unachievable using conventional semiconductors. Here we
demonstrate an ultrafast metal-semiconductor-metal heterojunction
photodetector, made of MoS2 and amorphous silicon (a-Si), with rise and fall
times of about 0.3 ms. This is more than an order of magnitude improvement over
response times of conventional a-Si (~5 ms) and best reported MoS2 devices (~50
ms). The van-der-waals heterojunction presented here yields a high
photoresponsivity of 210 mA/W at green light-the wavelength used in commercial
imaging systems. This responsivity is 4X larger than that of the best MoS2
devices, and 2X larger than that of commercial a-Si devices. The 10X
improvement in speed with high photoresponsivity provides a potential solution
to a decades-long problem for thin film imagers and could find applications in
large area electronics such as biomedical imaging and x-ray fluoroscopy.


title:
An Elementary Approach to Weight Multiplicities in Bivariate Irreducible
  Representations of Sp(2r)

abstract:
  By bivariate irreducible representations of ${\rm Sp}(2r)$, we mean
irreducible representations with highest weights containing at most two nonzero
entries, using the usual identification of dominant weights for complex
symplectic Lie algebras and their corresponding Lie groups as $r$-tuples in
decreasing non-negative integers. This paper has two aims. The first aim is to
provide a formula for the weight mulitplicities of said representations, which
is easily computable. The second aim is to present these weight multiplicities
using elementary means. The formula for these weight multiplicities is derived
using basic multiliear algebra and combinatorial arguments through explicit
descriptions of weight vectors.


title:
The role of the non-Gaussianity plays in the enhancement of the fidelity
  in continuous variable quantum teleportation

abstract:
  We investigated the role of non-Gaussianity (nG) plays in the enhancement of
the fidelity in continuous-variable quantum teleportation of ideal Braunstein
and Kimble (BK) protocol for coherent states, theoretically. The
de-Gaussification procedure is realized through subtracting photons on the
two-mode squeezed vacuum state (TMSVs). We find that the high fidelity always
refers to a symmetrical arrangement of photon subtractions on the different
modes of the TMSVs. The non-Gaussian resources demonstrate commendable
superiorities compare with the Gaussian resources only for symmetrical
arrangements of photon subtractions, however, the asymmetrical arrangements do
not. When the total number of photon subtractions be a constant, we find that
the optimal nG procedure prefers the most asymmetrical arrangement of
subtractions. This characteristic is not consistent with the result that the
highest fidelity refers to a symmetrical case. Under the same squeezing
parameter, a higher nG might not always lead to a higher fidelity.


title: On a Seminal Paper by Karlin and McGregor

abstract:
  The use of spectral methods to study birth-and-death processes was pioneered
by S. Karlin and J. McGregor. Their expression for the transition probabilities
was made explicit by them in a few cases. Here we complete their analysis and
indicate a few applications of their very powerful method.


title: Inductive Sparse Subspace Clustering

abstract:
  Sparse Subspace Clustering (SSC) has achieved state-of-the-art clustering
quality by performing spectral clustering over a $\ell^{1}$-norm based
similarity graph. However, SSC is a transductive method which does not handle
with the data not used to construct the graph (out-of-sample data). For each
new datum, SSC requires solving $n$ optimization problems in O(n) variables for
performing the algorithm over the whole data set, where $n$ is the number of
data points. Therefore, it is inefficient to apply SSC in fast online
clustering and scalable graphing. In this letter, we propose an inductive
spectral clustering algorithm, called inductive Sparse Subspace Clustering
(iSSC), which makes SSC feasible to cluster out-of-sample data. iSSC adopts the
assumption that high-dimensional data actually lie on the low-dimensional
manifold such that out-of-sample data could be grouped in the embedding space
learned from in-sample data. Experimental results show that iSSC is promising
in clustering out-of-sample data.