title: The rise of SN2014J in the nearby galaxy M82

abstract:
  We report on the discovery of SN2014J in the nearby galaxy M82. Given its
proximity, it offers the best opportunity to date to study a thermonuclear
supernova over a wide range of the electromagnetic spectrum. The first set of
optical, near-IR and mid-IR observations of SN2014J, orchestrated by the
intermediate Palomar Transient Factory (iPTF), show that SN2014J is a
spectroscopically normal Type Ia supernova, albeit exhibiting high-velocity
features in its spectrum and heavily reddened by dust in the host galaxy. Our
earliest detections start just hours after the fitted time of explosion. We use
high-resolution optical spectroscopy to analyze the dense intervening material
and do not detect any evolution in the resolved absorption features during the
lightcurve rise. Similarly to other highly reddened Type Ia supernovae, a low
value of total-to-selective extinction, Rv < 2, provides the best match to our
observations. We also study pre-explosion optical and near-IR images from HST
with special emphasis on the sources nearest to the SN location.


title: RADIA: RNA and DNA Integrated Analysis for Somatic Mutation Detection

abstract:
  The detection of somatic single nucleotide variants is a crucial component to
the characterization of the cancer genome. Mutation calling algorithms thus far
have focused on comparing the normal and tumor genomes from the same
individual. In recent years, it has become routine for projects like The Cancer
Genome Atlas (TCGA) to also sequence the tumor RNA. Here we present RADIA (RNA
and DNA Integrated Analysis), a method that combines the patient-matched normal
and tumor DNA with the tumor RNA to detect somatic mutations. The inclusion of
the RNA increases the power to detect somatic mutations, especially at low DNA
allelic frequencies. By integrating the DNA and RNA, we are able to rescue back
calls that would be missed by traditional mutation calling algorithms that only
examine the DNA.
  RADIA was developed for the identification of somatic mutations using both
DNA and RNA from the same individual. We demonstrate high sensitivity (84%) and
very high specificity (98% and 99%) in real data from endometrial carcinoma and
lung adenocarcinoma from TCGA. Mutations with both high DNA and RNA read
support have the highest validation rate of over 99%. We also introduce a
simulation package that spikes in artificial mutations to real data, rather
than simulating sequencing data from a reference genome. We evaluate
sensitivity on the simulation data and demonstrate our ability to rescue back
calls at low DNA allelic frequencies by including the RNA. Finally, we
highlight mutations in important cancer genes that were rescued back due to the
incorporation of the RNA.
  Software available at https://github.com/aradenbaugh/radia/


title: Interval scheduling and colorful independent sets

abstract:
  Numerous applications in scheduling, such as resource allocation or steel
manufacturing, can be modeled using the NP-hard Independent Set problem (given
an undirected graph and an integer k, find a set of at least k pairwise
non-adjacent vertices). Here, one encounters special graph classes like 2-union
graphs (edge-wise unions of two interval graphs) and strip graphs (edge-wise
unions of an interval graph and a cluster graph), on which Independent Set
remains NP-hard but admits constant-ratio approximations in polynomial time. We
study the parameterized complexity of Independent Set on 2-union graphs and on
subclasses like strip graphs. Our investigations significantly benefit from a
new structural "compactness" parameter of interval graphs and novel problem
formulations using vertex-colored interval graphs. Our main contributions are:
  1. We show a complexity dichotomy: restricted to graph classes closed under
induced subgraphs and disjoint unions, Independent Set is polynomial-time
solvable if both input interval graphs are cluster graphs, and is NP-hard
otherwise.
  2. We chart the possibilities and limits of effective polynomial-time
preprocessing (also known as kernelization).
  3. We extend Halld\'orsson and Karlsson (2006)'s fixed-parameter algorithm
for Independent Set on strip graphs parameterized by the structural parameter
"maximum number of live jobs" to show that the problem (also known as Job
Interval Selection) is fixed-parameter tractable with respect to the parameter
k and generalize their algorithm from strip graphs to 2-union graphs.
Preliminary experiments with random data indicate that Job Interval Selection
with up to fifteen jobs and 5*10^5 intervals can be solved optimally in less
than five minutes.


title: Monodisperse cluster crystals: classical and quantum dynamics

abstract:
  We study the phases and dynamics of a gas of monodisperse particles
interacting via soft-core potentials in two spatial dimensions, which is of
interest for soft-matter colloidal systems and quantum atomic gases. Using
exact theoretical methods, we demonstrate that the equilibrium low-temperature
classical phase simultaneously breaks continuous translational symmetry and
dynamic space-time homogeneity, whose absence is usually associated with
out-of-equilibrium glassy phenomena. This results in an exotic self-assembled
cluster crystal with coexisting liquid-like long-time dynamical properties,
which corresponds to a classical analog of supersolid behavior. We demonstrate
that the effects of quantum fluctuations and bosonic statistics on
cluster-glassy crystals are separate and competing: zero-point motion tends to
destabilize crystalline order, which can be restored by bosonic statistics.


title:
First Dynamic Computation of Synchrotron Emission from the Cygnus A
  Radio Cavity; Evidence for Electron Pair Plasma in Cavity

abstract:
  Cosmic rays, thermal gas and magnetic fields in FRII radio cavities are
assumed to come entirely from winds flowing from just behind the jet shocks.
Combining analytic and computational methods, it is shown that the computed
radio-electron energy distribution and synchrotron emissivity spectra
everywhere in the Cygnus A radio cavity agrees with radio observations of the
Cygnus A lobes. The magnetic field energy density is small everywhere and
evolves passively in the post-shock wind. Most synchrotron emission arises in
recent post-shock material as it flows back along the radio cavity wall.
Because it experienced less adiabatic expansion, the magnetic field in this
young backflow is larger than elsewhere in the radio lobe, explaining the
observed radio synchrotron limb-brightening. The boundary backflow decelerates
due to small cavity pressure gradients, causing large-scale fields
perpendicular to the backflow (and synchrotron emission) to grow exponentially
unlike observations. However, if the field is random on subgrid (sub-kpc)
scales, the computed field reproduces both the magnitude and slowly decreasing
radio synchrotron emissivity observed along the backflow. The radio synchrotron
spectrum and image computed with a small-scale random field agree with VLA
observations. The total relativistic energy density in the post-jet shock
region required in computations to inflate the radio cavity matches the energy
density of relativistic electrons observed in the post-shock region of Cygnus
A. This indicates that the component in the jet and cavity that dominates the
dynamical evolution is a relativistic pair plasma.


title:
Advanced spectral analysis of ionospheric waves observed with sparse
  arrays

abstract:
  This paper presents a case study from a single, six-hour observing period to
illustrate the application of techniques developed for interferometric radio
telescopes to the spectral analysis of observations of ionospheric fluctuations
with sparse arrays. We have adapted the deconvolution methods used for making
high dynamic range images of cosmic sources with radio arrays to making
comparably high dynamic range maps of spectral power of wavelike ionospheric
phenomena. In the example presented here, we have used observations of the
total electron content (TEC) gradient derived from Very Large Array (VLA)
observations of synchrotron emission from two galaxy clusters at 330 MHz as
well as GPS-based TEC measurements from a sparse array of 33 receivers located
within New Mexico near the VLA. We show that these techniques provide a
significant improvement in signal to noise (S/N) of detected wavelike
structures by correcting for both measurement inaccuracies and wavefront
distortions. This is especially true for the GPS data when combining all
available satellite/receiver pairs, which probe a larger physical area and
likely have a wider variety of measurement errors than in the single-satellite
case. In this instance, we found the peak S/N of the detected waves was
improved by more than an order of magnitude. The data products generated by the
deconvolution procedure also allow for a reconstruction of the fluctuations as
a two-dimensional waveform/phase screen that can be used to correct for their
effects.


title:
AMS-02 data confronts acceleration of cosmic ray secondaries in nearby
  sources

abstract:
  We revisit the model proposed earlier to account for the observed increase in
the positron fraction in cosmic rays with increasing energy, in the light of
new data from the Alpha Magnetic Spectrometer (AMS-02) experiment. The model
accounts for the production and acceleration of secondary electrons and
positrons in nearby supernova remnants which results in an additional, harder
component that becomes dominant at high energies. By fitting this to AMS-02
data we can calculate the expected concomitant rise of the boron-to-carbon
ratio, as well as of the fraction of antiprotons. If these predictions are
confirmed by the forthcoming AMS-02 data it would conclusively rule out all
other proposed explanations, in particular dark matter annihilations or decays.


title: Network Traffic Anomaly Detection

abstract:
  This paper presents a tutorial for network anomaly detection, focusing on
non-signature-based approaches. Network traffic anomalies are unusual and
significant changes in the traffic of a network. Networks play an important
role in today's social and economic infrastructures. The security of the
network becomes crucial, and network traffic anomaly detection constitutes an
important part of network security. In this paper, we present three major
approaches to non-signature-based network detection: PCA-based, sketch-based,
and signal-analysis-based. In addition, we introduce a framework that subsumes
the three approaches and a scheme for network anomaly extraction. We believe
network anomaly detection will become more important in the future because of
the increasing importance of network security.


title:
Fully Constrained Majorana Neutrino Mass Matrices using
  $\Sigma(72\times3)$

abstract:
  In 2002, two neutrino mixing ansatze having trimaximally mixed middle
($\nu_2$) columns, namely tri-chi-maximal mixing ($\text{T}\chi\text{M}$) and
tri-phi-maximal mixing ($\text{T}\phi\text{M}$), were proposed. It was recently
shown that $\text{T}\chi\text{M}$ with $\chi=\pm \frac{\pi}{16}$ as well as
$\text{T}\phi\text{M}$ with $\phi = \pm \frac{\pi}{16}$ leads to the solution,
$\sin^2 \theta_{13} = \frac{2}{3} \sin^2 \frac{\pi}{16}$, consistent with the
latest measurements of the reactor mixing angle, $\theta_{13}$. To obtain
$\text{T}\chi\text{M}_{(\chi=\pm \frac{\pi}{16})}$ and
$\text{T}\phi\text{M}_{(\phi=\pm \frac{\pi}{16})}$, we utilised the type I
see-saw framework with fully constrained Majorana neutrino mass matrices. These
mass matrices also resulted in a relation among the neutrino masses,
$m_1:m_2:m_3=\frac{\left(2+\sqrt{2}\right)}{1+\sqrt{2(2+\sqrt{2})}}:1:\frac{\left(2+\sqrt{2}\right)}{-1+\sqrt{2(2+\sqrt{2})}}$.
In this paper we construct a flavour model based on the discrete group
$\Sigma(72\times3)$ and obtain the aforementioned results. A Majorana neutrino
mass matrix (a symmetric $3\times3$ matrix with 6 complex degrees of freedom)
is conveniently mapped into a flavon field transforming as the complex 6
dimensional representation of $\Sigma(72\times3)$. Specific vacuum alignments
of the flavons are used to arrive at the desired mass matrices.


title: Robust Satisfiability of Systems of Equations

abstract:
  We study the problem of \emph{robust satisfiability} of systems of nonlinear
equations, namely, whether for a given continuous function
$f:\,K\to\mathbb{R}^n$ on a~finite simplicial complex $K$ and $\alpha>0$, it
holds that each function $g:\,K\to\mathbb{R}^n$ such that $\|g-f\|_\infty \leq
\alpha$, has a root in $K$. Via a reduction to the extension problem of maps
into a sphere, we particularly show that this problem is decidable in
polynomial time for every fixed $n$, assuming $\dim K \le 2n-3$. This is a
substantial extension of previous computational applications of
\emph{topological degree} and related concepts in numerical and interval
analysis. Via a reverse reduction we prove that the problem is undecidable when
$\dim K\ge 2n-2$, where the threshold comes from the \emph{stable range} in
homotopy theory. For the lucidity of our exposition, we focus on the setting
when $f$ is piecewise linear. Such functions can approximate general continuous
functions, and thus we get approximation schemes and undecidability of the
robust satisfiability in other possible settings.


title:
The Informed Sampler: A Discriminative Approach to Bayesian Inference in
  Generative Computer Vision Models

abstract:
  Computer vision is hard because of a large variability in lighting, shape,
and texture; in addition the image signal is non-additive due to occlusion.
Generative models promised to account for this variability by accurately
modelling the image formation process as a function of latent variables with
prior beliefs. Bayesian posterior inference could then, in principle, explain
the observation. While intuitively appealing, generative models for computer
vision have largely failed to deliver on that promise due to the difficulty of
posterior inference. As a result the community has favoured efficient
discriminative approaches. We still believe in the usefulness of generative
models in computer vision, but argue that we need to leverage existing
discriminative or even heuristic computer vision methods. We implement this
idea in a principled way with an "informed sampler" and in careful experiments
demonstrate it on challenging generative models which contain renderer programs
as their components. We concentrate on the problem of inverting an existing
graphics rendering engine, an approach that can be understood as "Inverse
Graphics". The informed sampler, using simple discriminative proposals based on
existing computer vision technology, achieves significant improvements of
inference.


title: Decomposition of random graphs into complete bipartite graphs

abstract:
  We consider the problem of partitioning the edge set of a graph $G$ into the
minimum number $\tau(G)$ of edge-disjoint complete bipartite subgraphs. We show
that for a random graph $G$ in $G(n,p)$, for $p$ is a constant no greater than
$1/2$, almost surely $\tau(G)$ is between $n- c(\ln_{1/p} n)^{3+\epsilon}$ and
$n - 2\ln_{1/(1-p)} n$ for any positive constants $c$ and $\epsilon$.


title: Voting for Committees in Agreeable Societies

abstract:
  We examine the following voting situation. A committee of $k$ people is to be
formed from a pool of n candidates. The voters selecting the committee will
submit a list of $j$ candidates that they would prefer to be on the committee.
We assume that $j \leq k < n$. For a chosen committee, a given voter is said to
be satisfied by that committee if her submitted list of $j$ candidates is a
subset of that committee. We examine how popular is the most popular committee.
In particular, we show there is always a committee that satisfies a certain
fraction of the voters and examine what characteristics of the voter data will
increase that fraction.


title: Fair Division and Redistricting

abstract:
  Recently, Landau, Reid and Yershov provided a novel solution to the problem
of redistricting. Instead of trying to ensure fairness by restricting the shape
of the possible maps or by assigning the power to draw the map to nonbiased
entities, the solution ensures fairness by balancing competing interests
against each other. This kind of solution is an example of what are known as
"fair division" solutions--- such solutions involve the preferences of all
parties and are accompanied by rigorous guarantees of a specified well-defined
notion of fairness. In this expository article, we give an introduction to the
ideas of fair division in the context of this redistricting solution. Through
examples and discussion we clarify how fair division methods can play an
important role in a realistic redistricting solution by introducing an
interactive step that incorporates a certain kind of fairness that can be used
in concert with, and not a substitute for, other necessary or desired criteria
for a good redistricting solution.


title:
A comparison of Euclidean metrics and their application in statistical
  inferences in the spike train space

abstract:
  Statistical analysis and inferences on spike trains are one of the central
topics in neural coding. It is of great interest to understand the underlying
distribution and geometric structure of given spike train data. However, a
fundamental obstacle is that the space of all spike trains is not an Euclidean
space, and non-Euclidean metrics have been commonly used in the literature to
characterize the variability and pattern in neural observations. Over the past
few years, two Euclidean-like metrics were independently developed to measure
distance in the spike train space. An important benefit of these metrics is
that the spike train space will be suitable for embedding in Euclidean spaces
due to their Euclidean properties. In this paper, we systematically compare
these two metrics on theory, properties, and applications. Because of its
Euclidean properties, one of these metrics has been further used in defining
summary statistics (i.e. mean and variance) and conducting statistical
inferences in the spike train space. Here we provide equivalent definitions
using the other metric and show that consistent statistical inferences can be
conducted. We then apply both inference frameworks in a neural coding problem
for a recording in geniculate ganglion stimulated by different tastes. It is
found that both frameworks achieve desirable results and provide useful new
tools in statistical inferences in neural spike train space.


title: Shadowing correction to the gluon distribution behavior at small x

abstract:
  We determined the saturation exponent of the gluon distribution using the
solution of the QCD nonlinear Dokshitzer-Gribov-Lipatov-Altarelli-parisi
(NLDGLAP) evolution equation at small $x$. The very small $x$ behavior of the
gluon distribution is obtained by solving the Gribov, Levin, Ryskin, Mueller
and Qiu (GLR-MQ) evolution equation with the nonlinear shadowing term
incorporated. The form of initial condition for the equation is determined. We
find, with decreasing $x$, the emergence of a singular behavior and the
eventual taming (at $R=5\hspace{0.1cm}GeV^{-1}$) and the essential taming (at
$R=2\hspace{0.1cm}GeV^{-1}$) of this singular behavior by shadowing term. The
nonlinear gluon density functions are calculated and compared with the results
for the integrated gluon density from the Balitsky- Kovchegov(BK) equation for
the different values of $Q^{2}$. It is shown, that the results for the gluon
density function are comparable with the results obtained from BK equation
solution. Also we show that for each $x$, the $Q^{2}$ dependence of the data is
well described by gluon shadowing corrections to GLR-MQ equation. The resulting
analytic expression allow us to predict the logarithmic derivative
$\frac{{\partial}F^{s}_{2}(x,Q^{2})}{{\partial}lnQ^{2}}$ and to compare the
results with H1 data and a QCD analysis fit.


title: On Statistics of the Riemann Zeros Differences

abstract:
  Numerical study of the distribution of the Riemann zeros differences
following the work [1] shows the significance of the function for which the
prime sum expression is proposed. Computational results related to this
definition explored with various prime cut-offs.


title: Bulge Growth and Quenching since z = 2.5 in CANDELS/3D-HST

abstract:
  Exploiting the deep high-resolution imaging of all 5 CANDELS fields, and
accurate redshift information provided by 3D-HST, we investigate the relation
between structure and stellar populations for a mass-selected sample of 6764
galaxies above 10^10 Msun, spanning the redshift range 0.5 < z < 2.5. For the
first time, we fit 2-dimensional models comprising a single Sersic fit and
two-component (i.e., bulge + disk) decompositions not only to the H-band light
distributions, but also to the stellar mass maps reconstructed from resolved
stellar population modeling. We confirm that the increased bulge prominence
among quiescent galaxies, as reported previously based on rest-optical
observations, remains in place when considering the distributions of stellar
mass. Moreover, we observe an increase of the typical Sersic index and
bulge-to-total ratio (with median B/T reaching 40-50%) among star-forming
galaxies above 10^11 Msun. Given that quenching for these most massive systems
is likely to be imminent, our findings suggest that significant bulge growth
precedes a departure from the star-forming main sequence. We demonstrate that
the bulge mass (and ideally knowledge of the bulge and total mass) is a more
reliable predictor of the star-forming versus quiescent state of a galaxy than
the total stellar mass. The same trends are predicted by the state-of-the-art
semi-analytic model by Somerville et al. In the latter, bulges and black holes
grow hand in hand through merging and/or disk instabilities, and AGN-feedback
shuts off star formation. Further observations will be required to pin down
star formation quenching mechanisms, but our results imply they must be
internal to the galaxies and closely associated with bulge growth.


title:
The Big Problems in Star Formation: the Star Formation Rate, Stellar
  Clustering, and the Initial Mass Function

abstract:
  Star formation lies at the center of a web of processes that drive cosmic
evolution: generation of radiant energy, synthesis of elements, formation of
planets, and development of life. Decades of observations have yielded a
variety of empirical rules about how it operates, but at present we have no
comprehensive, quantitative theory. In this review I discuss the current state
of the field of star formation, focusing on three central questions: what
controls the rate at which gas in a galaxy converts to stars? What determines
how those stars are clustered, and what fraction of the stellar population ends
up in gravitationally-bound structures? What determines the stellar initial
mass function, and does it vary with star-forming environment? I use these
three question as a lens to introduce the basics of star formation, beginning
with a review of the observational phenomenology and the basic physical
processes. I then review the status of current theories that attempt to solve
each of the three problems, pointing out links between them and opportunities
for theoretical and numerical work that crosses the scale between them. I
conclude with a discussion of prospects for theoretical progress in the coming
years.


title:
ICM cooling, AGN feedback and BCG properties of galaxy groups-Five
  properties where groups differ from clusters

abstract:
  Using Chandra data for a sample of 26 galaxy groups, we constrained the
central cooling times (CCTs) of the ICM and classified the groups as strong
cool-core (SCC), weak cool-core (WCC) and non-cool-core (NCC) based on their
CCTs. The total radio luminosity of the brightest cluster galaxy (BCG) was
obtained using radio catalog data and literature, which was compared to the CCT
to understand the link between gas cooling and radio output. We determined
K-band luminosities of the BCG with 2MASS data, and used it to constrain the
masses of the SMBH, which were then compared to the radio output. We also
tested for correlations between the BCG luminosity and the overall X-ray
luminosity and mass of the group.
  The observed cool-core/non-cool-core fractions for groups are comparable to
those of clusters. However, notable differences are seen. For clusters, all
SCCs have a central temperature drop, but for groups, this is not the case as
some SCCs have centrally rising temperature profiles. While for the cluster
sample, all SCC clusters have a central radio source as opposed to only 45% of
the NCCs, for the group sample, all NCC groups have a central radio source as
opposed to 77% of the SCC groups. For clusters, there are indications of an
anticorrelation trend between radio luminosity and CCT which is absent for the
groups. Indications of a trend of radio luminosity with black hole mass
observed in SCC clusters is absent for groups. The strong correlation observed
between the BCG luminosity and the cluster X-ray luminosity/cluster mass
weakens significantly for groups.
  We conclude that there are important differences between clusters and groups
within the ICM cooling/AGN feedback paradigm.


title:
A Unified Treatment of the QCD Evolution of All (Un-)Polarized TMD
  Functions: Collins Function as a Study Case

abstract:
  By considering semi-inclusive deep-inelastic scattering and the
(complementary) $q_T$-spectrum for Drell-Yan lepton pair production we derive
the QCD evolution for all the leading-twist transverse momentum dependent
distribution and fragmentation functions. We argue that all of those functions
evolve with $Q^2$ following a \emph{single} evolution kernel. This kernel is
independent of the underlying kinematics and it is also spin-independent. Those
features hold, in impact parameter space, to all values of $b_T$. The evolution
kernel presented has all of its large logarithms resummed up next-to-next-to
leading logarithmic accuracy, which is the highest possible accuracy given
existing perturbative calculations. As a study case we apply this kernel to
investigate the evolution of Collins function, one of the ingredients that have
attracted recently much attention within the phenomenological studies of spin
asymmetries. Our analysis can be readily implemented to revisit previously
obtained fits that involve data at different scales for other spin-dependent
functions. Such improved fits are important to get better predictions --with
the correct evolution kernel-- for certain upcoming experiments aiming to
measure Sivers function, Collins function, transversity and other
spin-dependent functions as well.


title:
Power asymmetry in WMAP and Planck temperature sky maps as measured by a
  local variance estimator

abstract:
  We revisit the question of hemispherical power asymmetry in the WMAP and
Planck temperature sky maps by measuring the local variance over the sky and on
disks of various sizes. For the 2013 Planck sky map we find that none of the
1000 available isotropic Planck "Full Focal Plane" simulations have a larger
variance asymmetry than that estimated from the data, suggesting the presence
of an anisotropic signature formally significant at least at the $3.3\sigma$
level. For the WMAP 9-year data we find that 5 out of 1000 simulations have a
larger asymmetry. The preferred direction for the asymmetry from the Planck
data is $(l,b)=(212^\circ,-13^\circ)$, in good agreement with previous reports
of the same hemispherical power asymmetry.


title:
Quantum Spectral Curve at Work: From Small Spin to Strong Coupling in
  N=4 SYM

abstract:
  We apply the recently proposed quantum spectral curve technique to the study
of twist operators in planar N=4 SYM theory. We focus on the small spin
expansion of anomalous dimensions in the sl(2) sector and compute its first two
orders exactly for any value of the 't Hooft coupling. At leading order in the
spin S we reproduced Basso's slope function. The next term of order S^2
structurally resembles the Beisert-Eden-Staudacher dressing phase and takes
into account wrapping contributions. This expansion contains rich information
about the spectrum of local operators at strong coupling. In particular, we
found a new coefficient in the strong coupling expansion of the Konishi
operator dimension and confirmed several previously known terms. We also
obtained several new orders of the strong coupling expansion of the BFKL
pomeron intercept. As a by-product we formulated a prescription for the correct
analytical continuation in S which opens a way for deriving the BFKL regime of
twist two anomalous dimensions from AdS/CFT integrability.


title: Disordered horizons: Holography of randomly disordered fixed points

abstract:
  We deform conformal field theories with classical gravity duals by marginally
relevant random disorder. We show that the disorder generates a flow to IR
fixed points with a finite amount of disorder. The randomly disordered fixed
points are characterized by a dynamical critical exponent $z>1$ that we obtain
both analytically (via resummed perturbation theory) and numerically (via a
full simulation of the disorder). The IR dynamical critical exponent increases
with the magnitude of disorder, probably tending to $z \to \infty$ in the limit
of infinite disorder.


title: Detecting quadrupole interactions in ultracold Fermi gases

abstract:
  We propose to detect quadrupole interactions of neutral ultra-cold atoms via
their induced mean-field shift. We consider a Mott insulator state of
spin-polarized atoms in a two-dimensional optical square lattice. The
quadrupole moments of the atoms are aligned by an external magnetic field. As
the alignment angle is varied, the mean-field shift shows a characteristic
angular dependence, which constitutes the defining signature of the quadrupole
interaction. For the $^{3}P_{2}$ states of Yb and Sr atoms, we find a frequency
shift of the order of tens of Hertz, which can be realistically detected in
experiment with current technology. We compare our results to the mean-field
shift of a spin-polarized quasi-2D Fermi gas in continuum.


title: Convection, granulation and period jitter in classical Cepheids

abstract:
  Analyses of recent observations of the sole classical Cepheid in the Kepler
field, V1154 Cygni, found random changes of about 30 minutes in the pulsation
period. These period changes challenge standard theories of pulsation and
evolution because the period change is non-secular, and explaining this period
jitter is necessary for understanding stellar evolution and the role of
Cepheids as precise standard candles. We suggest that convection and convective
hot spots can explain the observed period jitter. Convective hot spots alter
the timing of flux maximum and minimum in the Cepheid light curve, hence change
the measured pulsation period. We present a model of random hot spots that
generate a localized flux excess that perturbs the Cepheid light curve and
consequently the pulsation period which is consistent with the observed jitter.
This result demonstrates how important understanding convection is for modeling
Cepheid stellar structure and evolution, how convection determines the red edge
of the instability strip, and just how sensitive Cepheid light curves are to
atmospheric physics.


title: Quantum quenches and competing orders

abstract:
  We study the nonequilibrium dynamics of an electronic model of competition
between an unconventional charge density wave (a bond density wave) and
$d$-wave superconductivity. In a time-dependent Hartree-Fock+BCS approximation,
the dynamics reduces to the equations of motion of operators realizing the
generators of SU(4) at each pair of momenta, ( $\boldsymbol{k}$, -
$\boldsymbol{k}$ ), in the Brillouin zone. We also study the nonequilibrium
dynamics of a quantum generalization of a O(6) nonlinear $\sigma$ model of
competing orders in the underdoped cuprates [Hayward et al., Science
$\boldsymbol{343}$, 1336 (2014)]. We obtain results, in the large $N$ limit of
a O($N$) model, on the time dependence of correlation functions following a
pulse disturbance. We compare our numerical studies with recent picosecond
optical experiments. We find that, generically, the oscillatory responses in
our models share various qualitative features with the experiments.


title:
Hyperfine splitting in positronium to ${\cal O}(\alpha^7m_e)$:
  one-photon annihilation contribution

abstract:
  We present the complete result for the ${\cal O}(\alpha^7m_e)$ one-photon
annihilation contribution to the hyperfine splitting of the ground state energy
levels in positronium. Numerically it increases the prediction of quantum
electrodynamics by $217\pm 1$ kHz.


title: Benchmarking nuclear models for Gamow-Teller response

abstract:
  A comparative study of the nuclear Gamow-Teller response (GTR) within
conceptually different state-of-the-art approaches is presented. Three nuclear
microscopic models are considered: (i) the recently developed charge-exchange
relativistic time blocking approximation (RTBA) based on the covariant density
functional theory, (ii) the shell model (SM) with an extended "jj77" model
space and (iii) the non-relativistic quasiparticle random-phase approximation
(QRPA) with a Brueckner G-matrix effective interaction. We study the physics
cases where two or all three of these models can be applied. The Gamow-Teller
response functions are calculated for 208-Pb, 132-Sn and 78-Ni within both RTBA
and QRPA. The strengths obtained for 208-Pb are compared to data that enables a
firm model benchmarking. For the nucleus 132-Sn, also SM calculations are
performed within the model space truncated at the level of a particle-hole (ph)
coupled to vibration configurations. This allows a consistent comparison to the
RTBA where ph+phonon coupling is responsible for the spreading width and
considerable quenching of the GTR. Differences between the models and
perspectives of their future developments are discussed.


title: Energy carries Information

abstract:
  We show that for every qubit of quantum information, there is a well-defined
notion of "the amount of energy that carries it", because it is a conserved
quantity. This generalizes to larger systems and any conserved quantites: the
eigenvalue spectrum of conserved charges has to be preserved while transferring
quantum information. It is possible to "apparently" violate these conservations
by losing a small fraction of information, but that must invoke a specific
process which requires a large scale coherence. We discuss its implication
regarding the black hole information paradox.


title: Wrapping probabilities for Potts spin clusters on a torus

abstract:
  In this work we obtain wrapping probabilities for Ising spin clusters on a
torus. We use the analogy with the tricritical point of a Potts model with
dilution. The formula obtained are tested against numerical simulation. We also
provide closed form for the wrapping probabilities of cross clusters on
untwisted tori.


title: Neutrinos from charm production in the atmosphere

abstract:
  Atmospheric neutrinos are produced in interactions of cosmic rays with
Earth's atmosphere. At very high energy, the contribution from semi-leptonic
decays of charmed hadrons, known as the prompt neutrino flux, dominates over
the conventional flux from pion and kaon decays. This is due to the very short
lifetime of the charmed hadrons, which therefore do not lose energy before they
decay. The calculation of this process is difficult because the Bjorken-x at
which the parton distribution functions are evaluated is very small. This is a
region where QCD is not well understood, and large logarithms must be resummed.
Available parton distribution functions are not known at such small x and
extrapolations must be made. Theoretically, the fast rise of the structure
functions for small x ultimately leads to parton saturation. This contribution
describes the "ERS" calculation of the prompt neutrino flux, which includes
parton saturation effects in the QCD production cross section of charm quarks.
The ERS flux calculation is used by e.g. the IceCube collaboration as a
standard benchmark background. We are now updating this calculation to take
into account the recent LHC data on the charm cross section, as well as recent
theoretical developments in QCD. Some of the issues involved in this
calculation are described.


title: Laser-induced magnetization curve

abstract:
  We propose an all optical ultrafast method to highly magnetize general
quantum magnets using a circularly polarized terahertz laser. The key idea is
to utilize a circularly polarized laser and its chirping. Through this method,
one can obtain magnetization curves of a broad class of quantum magnets as a
function of time even without any static magnetic field. We numerically
demonstrate the laser-induced magnetization process in realistic quantum spin
models and find a condition for the realization. The onset of magnetization can
be described by a many-body version of Landau-Zener mechanism. In a particular
model, we show that a plateau state with topological properties can be realized
dynamically.


title: High-Redshift Star Formation in a Time-Dependent Lyman-Werner Background

abstract:
  The first generation of stars produces a background of Lyman-Werner (LW)
radiation which can photo-dissociate molecular hydrogen, increasing the mass of
dark matter halos required to host star formation. Previous studies have
determined the critical mass required for efficient molecular cooling with a
constant LW background. However, the true background is expected to increase
rapidly at early times. Neglecting this evolution could underestimate star
formation in small halos that may have started to cool in the past when the LW
intensity was much lower. Background evolution is a large source of uncertainty
in pre-reionization predictions of the cosmological 21cm signal, which can be
observed with future radio telescopes. To address this, we perform
zero-dimentional one-zone calculations that follow the density, chemical
abundances, and temperature of gas in the central regions of dark matter halos,
including hierarchical growth and an evolving LW background. We begin by
studying the physics of halos subjected to a background that increases
exponentially with redshift. We find that when the intensity increases more
slowly than $J_{\rm LW}(z) \propto 10^{-z/5}$, cooling in the past is a
relatively small effect. We then self-consistently compute the cosmological LW
background over $z=15-50$ and find that cooling in the past due to an evolving
background has a modest impact. Finally, we compare these results to
three-dimensional hydrodynamical cosmological simulations with varying LW
histories. While only a small number of halos were simulated, the results are
consistent with our one-zone calculations.


title: Weak splittings of quotients of Drinfeld and Heisenberg doubles

abstract:
  We investigate the fine structure of the simplectic foliations of Poisson
homogeneous spaces. Two general results are proved for weak splittings of
surjective Poisson submersions from Heisenberg and Drinfeld doubles. The
implications of these results are that the torus orbits of symplectic leaves of
the quotients can be explicitly realized as Poisson-Dirac submanifolds of the
torus orbits of the doubles. The results have a wide range of applications to
many families of real and complex Poisson structures on flag varieties. Their
torus orbits of leaves recover important families of varieties such as the open
Richardson varieties.


title: Perfect Packings in Quasirandom Hypergraphs

abstract:
  Let k >= 2 and F be a linear k-uniform hypergraph with v vertices. We prove
that if n is sufficiently large and v|n, then every quasirandom k-uniform
hypergraph on n vertices with constant edge density and minimum degree
$\Omega(n^{k-1})$ admits a perfect F-packing. The case k = 2 follows
immediately from the blowup lemma of Koml\'os, S\'ark\"ozy, and Szemer\'edi. We
also prove positive results for some nonlinear F but at the same time give
counterexamples for rather simple F that are close to being linear. Finally, we
address the case when the density tends to zero, and prove (in analogy with the
graph case) that sparse quasirandom 3-uniform hypergraphs admit a perfect
matching as long as their second largest eigenvalue is sufficiently smaller
than the largest eigenvalue.


title:
Dependence of synchronisation frequency of Kuramoto oscillators on
  symmetry of natural frequency distribution

abstract:
  Kuramoto oscillators have been proposed earlier as a model for interacting
systems that exhibit synchronisation. In this article we study the difference
between networks with symmetric and asymmetric distribution of natural
frequencies. We first indicate that the synchronisation frequency of the
oscillators is independent of the natural frequency distribution for a
completely connected network. Further we analyse the case of oscillators in a
directed ring-network where asymmetry in the natural frequency distribution is
seen to shift the synchronisation frequency of the network. We also present an
estimate of the shift in the frequencies for slightly asymmetric distributions.


title: A Secure Communication in Mobile Agent System

abstract:
  A mobile agent is a software code with mobility which can be move from a
computer into another computers through network. The mobile agent paradigm
provides many benefits in developments of distributed application at the same
time introduce new requirements for security issues with these systems. In this
article we present a solution for protection agent from other agents attacks
with loging patterns of malicious agent and useing this log for communication.
We implemented our resolution by JADE.


title:
Residually finite algorithmically finite groups, their subgroups and
  direct products

abstract:
  We construct an infinite finitely generated recursively presented residually
finite algorithmically finite group $G$ answering thereby a question of
Myasnikov and Osin. Moreover, $G$ is "very infinite" and "very algorithmically
finite" in the sense that $G$ contains an infinite abelian normal subgroup
while all finite Cartesian powers of $G$ are algorithmically finite (i.e., for
any positive integer $n$, there is no algorithm which writes out an infinite
sequence of pairwise different elements of $G^n$). We also state several
related problems.


title:
The MassiveBlack-II Simulation: The Evolution of Halos and Galaxies to
  z~0

abstract:
  (Abridged for arXiv)We investigate the properties of halos, galaxies and
blackholes to z=0 in the high resolution hydrodynamical simulation
MassiveBlack-II (MBII) which evolves a LCDM cosmology in a comoving volume
Vbox=100(Mpc/h)^3. MBII is the highest resolution simulation of this size which
includes a self-consistent model for star formation, black hole accretion and
associated feedback. We provide a simulation browser web application which
enables interactive search and tagging of halos, subhalos and their properties
and publicly release our galaxy catalogs. Our analysis of the halo mass
function (MF) in MBII reveals that baryons have strong effects, with changes in
the halo abundance of 20-35% below the knee of the MF (Mhalo < 10^13.2 Msun/h
at z=0) when compared to fits based on dark matter only simulations. We provide
a fitting function for the halo MF out to redshift z=11 and discuss how the
onset of non-universality in the MF limits the accuracy of our fit. We study
the halo occupation distribution and clustering of galaxies, in particular the
evolution and scale dependence of stochasticity and bias finding reasonable
agreement with observational data. The shape of the cosmic spectral energy
distribution predicted by MBII is consistent with observations, but lower in
amplitude. The Galaxy Stellar Mass Function (GSMF) function is broadly
consistent with observations at z>=2. At z<2, the population of passive low
mass (for M*<10^9 Msun) galaxies in MBII makes the GSMF too steep compared to
observations whereas at the high mass end (M*>10^11 Msun) galaxies hosting
bright AGNs make significant contributions to the GSMF. The quasar bolometric
luminosity function is also largely consistent with observations. We note
however that more efficient AGN feedback (beyond simple thermal coupling used
here) is likely necessary for the largest, rarest objects/clusters at low
redshifts.


title:
A Mid-Infrared Search for Substellar Companions of Nearby Planet-Host
  Stars

abstract:
  Determining the presence of widely separated substellar-mass companion is
crucial to understand the dynamics of inner planets in extrasolar planetary
systems (e.g. to explain their high mean eccentricity as inner planets are
perturbed by the Kozai mechanism). We report the results of our
$\textit{Spitzer}$/Infrared Array Camera (IRAC) imaging search for widely
separated (10 to 25$^{\prime\prime}$) substellar-mass companions for 14
planet-host stars within 15 pc of the Sun. Using deep 3.6 and 4.5 $\mu$m
observations in subarray mode, we found one object in the field of 47 UMa with
[3.6]$-$[4.5] color similar to a T5 dwarf, which is, however, unlikely to share
common proper motion with 47 UMa. We also found three objects with
brown-dwarf-like [3.6]$-$[4.5] color limits in the fields of GJ 86, HD 160691,
and GJ 581, as well as another in the field of HD 69830 for which we have
excluded common proper motion. We provide model-based upper mass limits for
unseen objects around all stars in our sample, with typical sensitivity to 10
M$_{J}$ objects from a projected separation of 50 to 300 au from the parent
star. We also discuss our data analysis methods for point-spread-function
subtraction, image co-alignment, and artifact subtraction of IRAC subarray
images.


title: Abelian Duality for Generalised Maxwell Theories

abstract:
  We describe a construction of generalized Maxwell theories -- higher
analogues of abelian gauge theories -- in the factorization algebra formalism
of Costello and Gwilliam, allowing for analysis of the structure of local
observables. We describe the phenomenon of abelian duality for local
observables in these theories as a form of Fourier duality, relating
observables in theories with dual abelian gauge groups and inverted coupling
constants in a way compatible with the local structure. We give a description
of expectation values in this theory and prove that duality preserves
expectation values. Duality is shown to, for instance, interchange higher
analogues of Wilson and 't Hooft operators.


title: Cosmological SUSY Breaking and the Pyramid Schemes

abstract:
  I review the ideas of holographic space-time (HST), Cosmological SUSY
breaking (CSB), and the Pyramid Schemes, which are the only known models of
Tera-scale physics consistent with CSB, current particle data, and gauge
coupling unification. There is considerable uncertainty in the estimate of the
masses of supersymmetric partners of the standard model particles, but the
model predicts that the gluino is probably out of reach of the LHC, squarks may
be in reach, and the NLSP is a right handed slepton, which should be discovered
soon.


title:
Factorial P- and Q-Schur functions represent equivariant quantum
  Schubert classes

abstract:
  We find presentations by generators and relations for the equivariant quantum
cohomology rings of the maximal isotropic Grassmannians of types B,C and D, and
we find polynomial representatives for the Schubert classes in these rings.
These representatives are given in terms of the same Pfaffian formulas which
appear in the theory of factorial $P$- and $Q$-Schur functions. After
specializing to equivariant cohomology, we interpret the resulting
presentations and Pfaffian formulas in terms of Chern classes of tautological
bundles.


title: CaIrO3: a Spin-Orbit Mott Insulator Beyond the jeff = 1/2 Ground State

abstract:
  In CaIrO3 electronic correlation, spin-orbit coupling, and tetragonal crystal
field splitting are predicted to be of comparable strength. However, the nature
of its ground state is still object of debate, with contradictory experimental
and theoretical results. We probe the ground state of CaIrO3 and assess the
effective tetragonal crystal field splitting and spin-orbit coupling at play in
this system by means of resonant inelastic x-ray scattering. We conclude that
insulating CaIrO3 is not a jeff = 1/2 iridate and discuss the consequences of
our finding to the interpretation of previous experiments. In particular, we
clarify how the Mott insulating state in iridates can be readily extended
beyond the jeff = 1/2 ground state.


title:
Multiple Lac-mediated loops revealed by Bayesian statistics and tethered
  particle motion

abstract:
  The bacterial transcription factor LacI loops DNA by binding to two separate
locations on the DNA simultaneously. Despite being one of the best-studied
model systems for transcriptional regulation, the number and conformations of
loop structures accessible to LacI remain unclear, though the importance of
multiple co-existing loops has been implicated in interactions between LacI and
other cellular regulators of gene expression. To probe this issue, we have
developed a new analysis method for tethered particle motion, a versatile and
commonly-used in vitro single-molecule technique. Our method, vbTPM, performs
variational Bayesian inference in hidden Markov models. It learns the number of
distinct states (i.e., DNA-protein conformations) directly from tethered
particle motion data with better resolution than existing methods, while easily
correcting for common experimental artifacts. Studying short (roughly 100 bp)
LacI-mediated loops, we provide evidence for three distinct loop structures,
more than previously reported in single-molecule studies. Moreover, our results
confirm that changes in LacI conformation and DNA binding topology both
contribute to the repertoire of LacI-mediated loops formed in vitro, and
provide qualitatively new input for models of looping and transcriptional
regulation. We expect vbTPM to be broadly useful for probing complex
protein-nucleic acid interactions.


title:
A polarity-induced defect mechanism for conductivity and magnetism at
  polar-nonpolar oxide interfaces

abstract:
  The discovery of conducting two-dimensional electron gas (2DEG) and magnetism
at the interface between insulating nonmagnetic oxides, as exemplified by the
polar LaAlO3 and nonpolar SrTiO3 has raised prospects for attaining interfacial
functionalities absent in the component materials. Yet, the microscopic origin
of such emergent phenomena remains unclear, posing obstacles to design of
improved functionalities. Using first principles defect calculations, we reveal
a unifying polarity-induced defect mechanism for both conductivity and
magnetism at polar-nonpolar interfaces of nonmagnetic insulating oxides. We
demonstrate that the polar-discontinuity across the interface triggers
thermodynamically the spontaneous formation of certain defects that in turn
cancel the polar field induced by the polar discontinuity. It turns out that
the 2DEG originates from those spontaneously formed surface donor defects
(oxygen vacancy), but the density of 2DEG is controlled by the interfacial
anti-site acceptor defects (Al-on-Ti). The interface magnetism is found to
originate from the un-ionized deep Ti-on-Al anti-site donor defects within the
LaAlO3 side near the interface. Our results suggest practical design guidelines
for inducing and controlling both 2DEG and magnetism at polar-nonpolar oxide
interfaces.


title: Division Algebra Cyclicity in Prime Degree over a p-Adic Curve

abstract:
  We reprove two results of Saltman, Theorem 5.1 and Corollary 5.2 of [Sa07]:
If F is the function field of a smooth p-adic curve and D is an F-division
algebra of prime degree l\neq p, then D is Z/l-cyclic, and that if D is an
F-division algebra of prime period l\neq p then D has index l if and only if
its ramification locus on a suitable 2-dimensional model forF has no "hot
points".


title: Automata theory in nominal sets

abstract:
  We study languages over infinite alphabets equipped with some structure that
can be tested by recognizing automata. We develop a framework for studying such
alphabets and the ensuing automata theory, where the key role is played by an
automorphism group of the alphabet. In the process, we generalize nominal sets
due to Gabbay and Pitts.


title: Interference Channels with Half-Duplex Source Cooperation

abstract:
  The performance gain by allowing half-duplex source cooperation is studied
for Gaussian interference channels. The source cooperation is {\em in-band},
meaning that each source can listen to the other source's transmission, but
there is no independent (or orthogonal) channel between the sources. The
half-duplex constraint supposes that at each time instant the sources can
either transmit or listen, but not do both.
  Our main result is a characterization of the sum capacity when the
cooperation is bidirectional and the channel gains are symmetric. With
unidirectional cooperation, we essentially have a cognitive radio channel. By
requiring the primary to achieve a rate close to its link capacity, the best
possible rate for the secondary is characterized within a constant. Novel inner
and outer bounds are derived as part of these characterizations.


title:
General relativistic modelling of the negative reverberation X-ray time
  delays in AGN

abstract:
  We present the first systematic physical modelling of the time-lag spectra
between the soft (0.3-1 keV) and the hard (1.5-4 keV) X-ray energy bands, as a
function of Fourier frequency, in a sample of 12 active galactic nuclei which
have been observed by XMM-Newton. We concentrate particularly on the negative
X-ray time-lags (typically seen above $10^{-4}$ Hz) i.e. soft band variations
lag the hard band variations, and we assume that they are produced by
reprocessing and reflection by the accretion disc within a lamp-post X-ray
source geometry. We also assume that the response of the accretion disc, in the
soft X-ray bands, is adequately described by the response in the neutral iron
line (Fe k$\alpha$) at 6.4 keV for which we use fully general relativistic
ray-tracing simulations to determine its time evolution. These response
functions, and thus the corresponding time-lag spectra, yield much more
realistic results than the commonly-used, but erroneous, top-hat models.
Additionally we parametrize the positive part of the time-lag spectra
(typically seen below $10^{-4}$ Hz) by a power-law. We find that the
best-fitting BH masses, M, agree quite well with those derived by other
methods, thus providing us with a new tool for BH mass determination. We find
no evidence for any correlation between M and the BH spin parameter, $\alpha$,
the viewing angle, $\theta$, or the height of the X-ray source above the disc,
$h$. Also on average, the X-ray source lies only around 3.7 gravitational radii
above the accretion disc and the viewing angles are distributed uniformly
between 20 and 60 degrees. Finally, there is a tentative indication that the
distribution of spin parameters may be bimodal above and below 0.62.

categories: astro-ph.HE astro-ph.CO astro-ph.GA gr-qc


title:
On the norms of $p$-stabilized elliptic newforms (with an appendix by
  Keith Conrad)

abstract:
  Let $f \in S_{\kappa}(\Gamma_0(N))$ be a Hecke eigenform at $p$ with
eigenvalue $\lambda_f(p)$ for a prime $p$ not dividing $N$. Let $\alpha_p$ and
$\beta_p$ be complex numbers satisfying $\alpha_p + \beta_p = \lambda_f(p)$ and
$\alpha_p \beta_p = p^{\kappa-1}$. We calculate the norm of
$f_{p}^{\alpha_p}(z) = f(z) - \beta_{p} f(pz)$ as well as the norm of $U_p f$,
both classically and adelically. We use these results along with some
convergence properties of the Euler product defining the symmetric square
L-function of $f$ to give a `local' factorization of the Petersson norm of $f$.


title:
Cooperative effects of Jahn-Teller distortion, magnetism and Hund's
  coupling in the insulating phase of BaCrO$_3$

abstract:
  We employ a combination of density functional theory and dynamical mean-field
theory to investigate the electronic structure of the recently synthesized
insulator BaCrO$_3$. Our calculations show that Hund's coupling is responsible
for strong correlation effects, which are however not sufficient to turn the
system insulating. A finite Jahn-Teller distortion lifting the orbital
degeneracy is necessary to stabilize an insulating state with orbital ordering
and consequent magnetic ordering.


title:
Polycyclic aromatic hydrocarbon ionization as a tracer of gas flows
  through protoplanetary disk gaps

abstract:
  Planet-forming disks of gas and dust around young stars contain polycyclic
aromatic hydrocarbons (PAHs). We aim to characterize how the charge state of
PAHs can be used as a probe of flows of gas through protoplanetary gaps. In
this context, our goal is to understand the PAH spectra of four transitional
disks. In addition, we want to explain the observed correlation between PAH
ionization (traced by the 6.2/11.3 feature ratio) and the disk mass (traced by
the 1.3 mm luminosity). We implement a model to calculate the charge state of
PAHs in the radiative transfer code MCMax. The emission spectra and ionization
balance are calculated. A benchmark modeling grid is presented that shows how
PAH ionization and luminosity behave as a function of star and disk properties.
The PAH ionization is most sensitive to ultraviolet (UV) radiation and the
electron density. In optically thick disks, where the UV field is low and the
electron density is high, PAHs are predominantly neutral. Ionized PAHs trace
low-density optically thin disk regions where the UV field is high and the
electron density is low. Such regions are characteristic of gas flows through
the gaps of transitional disks. We demonstrate that fitting the PAH spectra of
four transitional disks requires a contribution of ionized PAHs in gas flows
through the gap. The PAH spectra of transitional disks can be understood as
superpositions of neutral and ionized PAHs. For HD97048, neutral PAHs in the
optically thick disk dominate the spectrum. In the cases of HD169142, HD135344B
and Oph IRS 48, small amounts of ionized PAHs located in the gas flows through
the gap are strong contributors to the total PAH luminosity. The observed trend
between the disk mass and PAH ionization may imply that lower-mass disks have
larger gaps. Ionized PAHs in gas flows through these gaps contribute strongly
to their spectra.


title: The shape of dark matter subhalos in the Aquarius simulations

abstract:
  We analyze the Aquarius simulations to characterize the shape of dark matter
halos with peak circular velocity in the range 8<Vmax<200 km/s, and perform a
convergence study using the various Aquarius resolution levels. For the
converged objects, we determine the principal axis (a<b<c) of the normalized
inertia tensor as a function of radius. We find that the triaxiality of field
halos is an increasing function of halo mass, so that the smallest halos in our
sample are ~40-50% rounder than Milky Way-like objects at the radius where the
circular velocity peaks, rmax. We find that the distribution of subhalo axis
ratios is consistent with that of field halos of comparable Vmax. Inner and
outer contours within each object are well aligned, with the major axis
preferentially pointing in the radial direction for subhalos closest to the
center of their host halo. We also analyze the dynamical structure of subhalos
likely to host luminous satellites comparable to the classical dwarf
spheroidals in the Local Group. These halos have axis ratios that increase with
radius, and which are mildly triaxial with <b/a>~0.75 and <c/a>~0.60 at r~1
kpc. Their velocity ellipsoid become strongly tangentially biased in the
outskirts as a consequence of tidal stripping.


title:
$M$-estimates for isotropic convex bodies and their $L_q$-centroid
  bodies

abstract:
  Let $K$ be a centrally-symmetric convex body in $\mathbb{R}^n$ and let
$\|\cdot\|$ be its induced norm on ${\mathbb R}^n$. We show that if $K
\supseteq r B_2^n$ then: \[ \sqrt{n} M(K) \leqslant C \sum_{k=1}^{n}
\frac{1}{\sqrt{k}} \min\left(\frac{1}{r} , \frac{n}{k} \log\Big(e +
\frac{n}{k}\Big) \frac{1}{v_{k}^{-}(K)}\right) . \] where $M(K)=\int_{S^{n-1}}
\|x\|\, d\sigma(x)$ is the mean-norm, $C>0$ is a universal constant, and
$v^{-}_k(K)$ denotes the minimal volume-radius of a $k$-dimensional orthogonal
projection of $K$. We apply this result to the study of the mean-norm of an
isotropic convex body $K$ in ${\mathbb R}^n$ and its $L_q$-centroid bodies. In
particular, we show that if $K$ has isotropic constant $L_K$ then: \[
  M(K) \leqslant \frac{C\log^{2/5}(e+ n)}{\sqrt[10]{n}L_K} . \]


title:
Magnetic field-induced spontaneous polarization reversal in multiferroic
  Mn$_{0.85}$Co$_{0.15}$WO$_4$

abstract:
  The magnetic and ferroelectric properties of the multiferroic system
Mn$_{1-x}$Co$_x$WO$_4$ (x=0.135, 0.15, and 0.17) are studied in magnetic fields
$H_c$ oriented along the monoclinic $c$-axis. Mn$_{0.85}$Co$_{0.15}$WO$_4$,
which is right at the phase boundary between two helical spin structures,
exhibits a spontaneous sign change of the ferroelectric polarization when
cooled in fields $H_c>$ 25 kOe. The origin of the ferroelectric polarization is
studied and two magnetic exchange interactions contributing to the polarization
are identified. In Mn$_{0.85}$Co$_{0.15}$WO$_4$ domains of the characteristic
helical spin structures, known for x$<$0.15 and x$>$0.15, coexist and form
domain boundaries. The contributions of the different domains to the global
polarization are determined. The polarization reversal in
Mn$_{0.85}$Co$_{0.15}$WO$_4$ can be explained by a combination of various
contributions to the polarization and a strong correlation between magnetic
domains of different helical spin orders resulting in a smooth transition
across the domain walls which preserves the chirality of the spin spiral.


title: Stochastic Quantum Gravity, Gravitational Collapse and Grey Holes

abstract:
  Quantum gravity is treated as a stochastic quantization of the spacetime
metric of general relativity. It is found that owing to the stochastic
fluctuating behavior of the geometry, the singularity in gravitational collapse
of a star has a zero probability density of occurring. Moreover, as a star
collapses the probability density of a distant observer seeing an infinite red
shift at the Schwarzschild radius of the star is zero. Therefore, there is a
vanishing probability density of a black hole event horizon forming during
gravitational collapse. A grey apparent event horizon forms during the collapse
that allows information to escape.


title: Anomalous discontinuity at the percolation critical point of active gels

abstract:
  We develop a percolation model motivated by recent experimental studies of
gels with active network remodeling by molecular motors. This remodeling was
found to lead to a critical state reminiscent of random percolation (RP), but
with a cluster distribution inconsistent with RP. Our model not only can
account for these experiments, but also exhibits an unusual type of mixed phase
transition: We find that the transition is characterized by signatures of
criticality, but with a discontinuity in the order parameter.


title:
Phase Diagram and Thermodynamic and Dynamic Anomalies in a Pure
  Repulsive Model

abstract:
  Using Monte Carlo simulations a lattice gas model with only repulsive
interactions was checked for the presence of anomalies. We show that this
system exhibits the density (temperature of maximum density - TMD) and
diffusion anomalies as present in liquid water. These anomalous behavior exist
in the region of the chemical potential vs temperature phase diagram where two
structured phases are present. A fragile-to-strong dynamic transition is also
observed in the vicinity of the TMD line.


title:
Construction of approximate entropy measure valued solutions for
  hyperbolic systems of conservation laws

abstract:
  Entropy solutions have been widely accepted as the suitable solution
framework for systems of conservation laws in several space dimensions.
However, recent results in \cite{CDL1,CDL2} have demonstrated that entropy
solutions may not be unique. In this paper, we present numerical evidence that
demonstrates that state of the art numerical schemes \emph{may not} necessarily
converge to an entropy solution of systems of conservation laws as the mesh is
refined. Combining these two facts, we argue that entropy solutions may not be
suitable as a solution framework for systems of conservation laws, particularly
in several space dimensions.
  Furthermore, we propose a more general notion, that of \emph{entropy measure
valued solutions}, as an appropriate solution paradigm for systems of
conservation laws. To this end, we present a detailed numerical procedure,
which constructs stable approximations to entropy measure valued solutions and
provide sufficient conditions that guarantee that these approximations converge
to an entropy measure valued solution as the mesh is refined, thus providing a
viable numerical framework for systems of conservation laws in several space
dimensions. A large number of numerical experiments that illustrate the
proposed schemes are presented and are utilized to examine several interesting
properties of the computed entropy measure valued solutions.


title: The $500.00 AAPL close: Manipulation or hedging? A quantitative analysis

abstract:
  Why do a market's prices move up or down? Claims about causes are made
without actual information, and accepted or dismissed based upon poor or
non-existent evidence. Here we investigate the price movements that ended with
Apple stock closing at \$500.00 on January 18, 2013. There is a ready
explanation for this price movement: market manipulation by those who sold
stock options, who stood to directly benefit from this closing price. Indeed,
one web commentator predicted this otherwise unlikely event publicly. This
explanation was subsequently dismissed by press articles that claim that stock
prices end near such round numbers based upon legitimate hedging activity. But
how can we know? We show that the accepted model that points to hedging as the
driving cause of prices is not quantitatively consistent with the price
movement on that day. The price moved upward too quickly over a period in which
the hedgers' position would require selling rather than buying. Under these
conditions hedgers would have driven the price away from the strike price
rather than toward it. We also show that a long published theory of the role of
hedging is incomplete mathematically, and that the correct theory results in
much weaker price movements. This evidence substantially weakens the case of
those who claim hedging as cause of anomalous market price movements. The
explanation that market manipulation is responsible for the final close cannot
be dismissed based upon unsubstantiated, even invalid, hedging claims. Such
proffered explanations shield potential illegal activity from further inquiry
even though the claims behind those explanations have not been demonstrated.


title:
A Policy Switching Approach to Consolidating Load Shedding and Islanding
  Protection Schemes

abstract:
  In recent years there have been many improvements in the reliability of
critical infrastructure systems. Despite these improvements, the power systems
industry has seen relatively small advances in this regard. For instance, power
quality deficiencies, a high number of localized contingencies, and large
cascading outages are still too widespread. Though progress has been made in
improving generation, transmission, and distribution infrastructure, remedial
action schemes (RAS) remain non-standardized and are often not uniformly
implemented across different utilities, ISOs, and RTOs. Traditionally, load
shedding and islanding have been successful protection measures in restraining
propagation of contingencies and large cascading outages. This paper proposes a
novel, algorithmic approach to selecting RAS policies to optimize the operation
of the power network during and after a contingency. Specifically, we use
policy-switching to consolidate traditional load shedding and islanding
schemes. In order to model and simulate the functionality of the proposed power
systems protection algorithm, we conduct Monte-Carlo, time-domain simulations
using Siemens PSS/E. The algorithm is tested via experiments on the IEEE-39
topology to demonstrate that the proposed approach achieves optimal power
system performance during emergency situations, given a specific set of RAS
policies.


title: Emergence of self-similarity in football dynamics

abstract:
  The multiplayer dynamics of a football game is analyzed to unveil
self-similarities in the time evolution of player and ball positioning.
Temporal fluctuations in both the team-turf boundary and the ball location are
uncovered to follow the rules of fractional Brownian motion with a Hurst
exponent of H=0.7. The persistence time below which self-similarity holds is
found to be several tens of seconds, implying a characteristic time scale that
governs far-from-equilibrium motion on a playing field.


title: Theory Summary

abstract:
  In this review, I show a personal overview of theoretical results shown in
the International Conference on the Initial Stages in High-Energy Nuclear
Collision, in Illa da Toxa, Galicia, Spain, Sept.~8-14, 2013.


title: Discovering Latent Network Structure in Point Process Data

abstract:
  Networks play a central role in modern data analysis, enabling us to reason
about systems by studying the relationships between their parts. Most often in
network analysis, the edges are given. However, in many systems it is difficult
or impossible to measure the network directly. Examples of latent networks
include economic interactions linking financial instruments and patterns of
reciprocity in gang violence. In these cases, we are limited to noisy
observations of events associated with each node. To enable analysis of these
implicit networks, we develop a probabilistic model that combines
mutually-exciting point processes with random graph models. We show how the
Poisson superposition principle enables an elegant auxiliary variable
formulation and a fully-Bayesian, parallel inference algorithm. We evaluate
this new model empirically on several datasets.


title: Learning Ordered Representations with Nested Dropout

abstract:
  In this paper, we study ordered representations of data in which different
dimensions have different degrees of importance. To learn these representations
we introduce nested dropout, a procedure for stochastically removing coherent
nested sets of hidden units in a neural network. We first present a sequence of
theoretical results in the simple case of a semi-linear autoencoder. We
rigorously show that the application of nested dropout enforces identifiability
of the units, which leads to an exact equivalence with PCA. We then extend the
algorithm to deep models and demonstrate the relevance of ordered
representations to a number of applications. Specifically, we use the ordered
property of the learned codes to construct hash-based data structures that
permit very fast retrieval, achieving retrieval in time logarithmic in the
database size and independent of the dimensionality of the representation. This
allows codes that are hundreds of times longer than currently feasible for
retrieval. We therefore avoid the diminished quality associated with short
codes, while still performing retrieval that is competitive in speed with
existing methods. We also show that ordered representations are a promising way
to learn adaptive compression for efficient online data reconstruction.


title: Bounds on Locally Recoverable Codes with Multiple Recovering Sets

abstract:
  A locally recoverable code (LRC code) is a code over a finite alphabet such
that every symbol in the encoding is a function of a small number of other
symbols that form a recovering set. Bounds on the rate and distance of such
codes have been extensively studied in the literature. In this paper we derive
upper bounds on the rate and distance of codes in which every symbol has $t\geq
1$ disjoint recovering sets.


title: Perturbing eigenvalues of non-negative matrices

abstract:
  Let $A$ be an irreducible (entrywise) nonnegative $n\times n$ matrix with
eigenvalues $$\rho, b+ic,b-ic, \lambda_4,\cdots,\lambda_n,$$ where $\rho$ is
the Perron eigenvalue. It is shown that for any $t \in [0, \infty)$ there is a
nonnegative matrix with eigenvalues $$\rho+ \tilde t,\lambda_2+t,\lambda_3+t,
\lambda_4 \cdots,\lambda_n,$$ whenever $\tilde t \ge \gamma_n t$ with
$\gamma_3=1, \gamma_4 = 2, \gamma_5=\sqrt 5$ and $\gamma_n = 2.25$ for $n \ge
6$. The result improves that of Guo et al. Our proof depends on an auxiliary
result in geometry asserting that the area of an $n$-sided convex polygon is
bounded by $\gamma_n$ times the maximum area of the triangle lying inside the
polygon.


title: Graphic-theoretic distributed inference in social networks

abstract:
  We consider distributed inference in social networks where a phenomenon of
interest evolves over a given social interaction graph, referred to as the
\emph{social digraph}. For inference, we assume that a network of agents
monitors certain nodes in the social digraph and no agent may be able to
perform inference within its neighborhood; the agents must rely on inter-agent
communication. The key contributions of this paper include: (i) a novel
construction of the distributed estimator and distributed observability from
the first principles; (ii) a graph-theoretic agent classification that
establishes the importance and role of each agent towards inference; (iii)
characterizing the necessary conditions, based on the classification in (ii),
on the agent network to achieve distributed observability. Our results are
based on structured systems theory and are applicable to any parameter choice
of the underlying system matrix as long as the social digraph remains fixed. In
other words, any social phenomena that evolves (linearly) over a
structure-invariant social digraph may be considered--we refer to such systems
as Liner Structure-Invariant (LSI). The aforementioned contributions,
(i)--(iii), thus, only require the knowledge of the social digraph (topology)
and are independent of the social phenomena. We show the applicability of the
results to several real-wold social networks, i.e. social influence among
monks, networks of political blogs and books, and a co-authorship graph.


title: Massive Star Formation

abstract:
  The enormous radiative and mechanical luminosities of massive stars impact a
vast range of scales and processes, from the reionization of the universe, to
the evolution of galaxies, to the regulation of the interstellar medium, to the
formation of star clusters, and even to the formation of planets around stars
in such clusters. Two main classes of massive star formation theory are under
active study, Core Accretion and Competitive Accretion. In Core Accretion, the
initial conditions are self-gravitating, centrally concentrated cores that
condense with a range of masses from the surrounding, fragmenting clump
environment. They then undergo relatively ordered collapse via a central disk
to form a single star or a small-N multiple. In this case, the pre-stellar core
mass function has a similar form to the stellar initial mass function. In
Competitive Accretion, the material that forms a massive star is drawn more
chaotically from a wider region of the clump without passing through a phase of
being in a massive, coherent core. In this case, massive star formation must
proceed hand in hand with star cluster formation. If stellar densities become
very high near the cluster center, then collisions between stars may also help
to form the most massive stars. We review recent theoretical and observational
progress towards understanding massive star formation, considering physical and
chemical processes, comparisons with low and intermediate-mass stars, and
connections to star cluster formation.


title: Diffusion coefficients in leaflets of bilayer membranes

abstract:
  We study diffusion coefficients of liquid domains by explicitly taking into
account the two-layered structure called leaflets of the bilayer membrane. In
general, the velocity fields associated with each leaflet are different and the
layers sliding past each other cause frictional coupling. We obtain analytical
results of diffusion coefficients for a circular liquid domain in a leaflet,
and quantitatively study their dependence on the inter-leaflet friction. We
also show that the diffusion coefficients diverge in the absence of coupling
between the bilayer and solvents, even when the inter-leaflet friction is taken
into account. In order to corroborate our theory, the effect of the
inter-leaflet friction on the correlated diffusion is examined.


title:
E- Exams System for Nigerian Universities with Emphasis on Security and
  Result Integrity

abstract:
  The recent employment and eventual widespread acceptance of electronic test
in examining students and various classes in Nigeria has created a significant
impact in the trends of educational history in the country. In this paper, we
examined the impacts, associated challenges and security lapses of the existing
electronic-examination system with the aim of ameliorating and developing a new
acceptable e-Exam system that takes care of the existing systems challenges and
security lapses. Six Universities that are already conducting e- Examination
were selected across the country for this research work. Twenty students that
participated in the e-exams and five members of staff were selected for
interview and questionnaire. Based on the analysis of the interviews and study
of the existing electronic examination system, some anomalies were discovered
and a new e-exams system was developed to eradicate these anomalies. The new
system uses data encryption in order to protect the questions sent to the
e-Examination center through the internet or intranet and a biometric
fingerprint authentication to screen the stakeholders.


title: Initial performance of the CUORE-0 experiment

abstract:
  CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide
bolometers to search for neutrinoless double-beta decay of ^{130}Te. We present
the first data analysis with 7.1 kg y of total TeO_2 exposure focusing on
background measurements and energy resolution. The background rates in the
neutrinoless double-beta decay region of interest (2.47 to 2.57 MeV) and in the
{\alpha} background-dominated region (2.70 to 3.90 MeV) have been measured to
be 0.071 \pm 0.011 and 0.019 \pm 0.002 counts/keV/kg/y, respectively. The
latter result represents a factor of 6 improvement from a predecessor
experiment, Cuoricino. The results verify our understanding of the background
sources in CUORE-0, which is the basis of extrapolations to the full CUORE
detector. The obtained energy resolution (full width at half maximum) in the
region of interest is 5.7 keV. Based on the measured background rate and energy
resolution in the region of interest, CUORE-0 half-life sensitivity is expected
to surpass the observed lower bound of Cuoricino with one year of live time.


title:
Measurement of inclusive W and Z boson production cross sections in pp
  collisions at sqrt(s) = 8 TeV

abstract:
  A measurement of total and fiducial inclusive W and Z boson production cross
sections in pp collisions at sqrt(s) = 8 TeV is presented. Electron and muon
final states are analyzed in a data sample collected with the CMS detector
corresponding to an integrated luminosity of 18.2 +/- 0.5 inverse picobarns.
The measured total inclusive cross sections times branching fractions are
sigma(pp to W X) B(W to l nu) = 12.21 +/- 0.03 (stat.) +/- 0.24 (syst.) +/-
0.32 (lum.) nb and sigma(pp to Z X) B(Z to l+ l-) = 1.15 +/- 0.01 (stat.) +/-
0.02 (syst.) +/- 0.03 (lum.) nb for the dilepton mass in the range of 60 to 120
GeV. The measured values agree with next-to-next-to-leading-order QCD cross
section calculations. Ratios of cross sections are reported with a precision of
2%. This is the first measurement of inclusive W and Z boson production in
proton-proton collisions at sqrt(s) = 8 TeV.


title:
Characteristic variety of the Gauss-Manin differential equations of a
  generic parallelly translated arrangement

abstract:
  We consider a weighted family of $n$ generic parallelly translated
hyperplanes in $\C^k$ and describe the characteristic variety of the
Gauss-Manin differential equations for associated hypergeometric integrals. The
characteristic variety is given as the zero set of Laurent polynomials, whose
coefficients are determined by weights and the Plucker coordinates of the
associated point in the Grassmannian Gr(k,n). The Laurent polynomials are in
involution.


title: An Information Identity for State-dependent Channels with Feedback

abstract:
  In this technical note, we investigate information quantities of
state-dependent communication channels with corrupted information fed back from
the receiver. We derive an information identity which can be interpreted as a
law of conservation of information flows.


title: Diabolical points in multi-scatterer optomechanical systems

abstract:
  Diabolical points, which originate from parameter-dependent accidental
degeneracies of a system's energy levels, have played a fundamental role in the
discovery of the Berry phase as well as in photonics (conical refraction), in
chemical dynamics, and more recently in novel materials such as graphene, whose
electronic band structure possess Dirac points. Here we discuss diabolical
points in an optomechanical system formed by multiple scatterers in an optical
cavity with periodic boundary conditions. Such configuration is close to
experimental setups using micro-toroidal rings with indentations or near-field
scatterers. We find that the optomechanical coupling is no longer an analytic
function near the diabolical point and demonstrate the topological phase
arising through the mechanical motion. Similar to a Fabry-Perot resonator, the
optomechanical coupling can grow with the number of scatterers. We also
introduce a minimal quantum model of a diabolical point, which establishes a
connection to the motion of an arbitrary-spin particle in a 2D parabolic
quantum dot with spin-orbit coupling.


title:
Anomalous dynamics of the extremely compressed magnetosphere during 21
  January 2005 magnetic storm

abstract:
  Dynamics of the dayside magnetosphere and proton radiation belt was analyzed
during unusual magnetic storm on 21 January 2005. We have found that during the
storm from 1712 to 2400 UT, the subsolar magnetopause was continuously located
inside geosynchronous orbit due to strong compression. The compression was
found to be extremely strong from 1846 to 2035 UT when the dense plasma of fast
erupting filament produced the solar wind dynamic pressure Pd peaked up to >100
nPa and, in the first time, the upstream solar wind was observed at
geosynchronous orbit during almost 2 hours. Under the extreme compression, the
outer magnetosphere at L > 5 was pushed inward and the outer radiation belt
particles with energies of several tens of keV moved earthward, became
adiabatically accelerated and accumulated in the inner magnetosphere at L < 4
that produced the intensified ring current with an exceptionally long lifetime.
The observations were compared with predictions of various empirical and first
principles models. All the models failed to predict the magnetospheric dynamics
under the extreme compression when the minimal magnetopause distance was
estimated to be ~3 Re. The inconsistencies between the model predictions and
observations might result from distortions of plasma measurements by extreme
heliospheric conditions consisting in very fast solar wind streams (~1000 km/s)
and intense fluxes of solar energetic particles. We speculated that anomalous
dynamics of the magnetosphere could be well described by the models if the He
abundance in the solar wind was assumed to be >20%, which is well appropriate
for erupting filaments and which is in agreement with the upper 27% threshold
for the He/H ratio obtained from Cluster measurements.


title: A Framework for Evaluation of Composite Memento Temporal Coherence

abstract:
  Most archived HTML pages embed other web resources, such as images and
stylesheets. Playback of the archived web pages typically provides only the
capture date (or Memento-Datetime) of the root resource and not the
Memento-Datetime of the embedded resources. In the course of our research, we
have discovered that the Memento-Datetime of embedded resources can be up to
several years in the future or past, relative to the Memento-Datetime of the
embedding root resource. We introduce a framework for assessing temporal
coherence between a root resource and its embedded resource depending on
Memento-Datetime, Last-Modified datetime, and entity body.


title: Input Warping for Bayesian Optimization of Non-stationary Functions

abstract:
  Bayesian optimization has proven to be a highly effective methodology for the
global optimization of unknown, expensive and multimodal functions. The ability
to accurately model distributions over functions is critical to the
effectiveness of Bayesian optimization. Although Gaussian processes provide a
flexible prior over functions which can be queried efficiently, there are
various classes of functions that remain difficult to model. One of the most
frequently occurring of these is the class of non-stationary functions. The
optimization of the hyperparameters of machine learning algorithms is a problem
domain in which parameters are often manually transformed a priori, for example
by optimizing in "log-space," to mitigate the effects of spatially-varying
length scale. We develop a methodology for automatically learning a wide family
of bijective transformations or warpings of the input space using the Beta
cumulative distribution function. We further extend the warping framework to
multi-task Bayesian optimization so that multiple tasks can be warped into a
jointly stationary space. On a set of challenging benchmark optimization tasks,
we observe that the inclusion of warping greatly improves on the
state-of-the-art, producing better results faster and more reliably.


title: WIMPy Leptogenesis

abstract:
  We consider a class of leptogenesis models in which the lepton asymmetry
arises from dark matter annihilation processes which violate CP and lepton
number. Importantly, a necessary one-loop contribution to the annihilation
matrix element arises from absorptive final state interactions. We elucidate
the relationship between this one-loop contribution and the CP-violating phase.
As we show, the branching fraction for dark matter annihilation to leptons may
be small in these models, while still generating the necessary asymmetry.


title:
Many-particle Majorana bound states: derivation and signatures in
  superconducting double quantum dots

abstract:
  We consider two interacting quantum dots coupled by standard superconductors.
We derive an effective Hamiltonian, and show that over a wide parameter range a
degenerate ground state can be obtained. An exotique form of Majorana bound
states are supported at these degeneracies, and the system can be adiabatically
tuned to a limit in which it is equivalent to the one-dimensional wire model of
Kitaev. We give the form of a Majorana bound state in this system in the strong
interaction limit in the many-particle picture. We also study the Josephson
current in this system, and demonstrate that a double slit-like pattern emerges
in the presence of an extra magnetic field. This pattern is shown to disappear
with increasing interaction strength, which is able to be explained as the
current being carried by chargeless Majorana modes.


title:
Tuning Collision Warning Algorithms to Individual Drivers for Design of
  Active Safety Systems

abstract:
  Every year, many people are killed and injured in highway traffic accidents.
In order to reduce such casualties, collisions warning systems has been studied
extensively. These systems are built by taking the driver reaction times into
account. However, most of the existing literature focuses on characterizing how
driver reaction times vary across an entire population. Therefore, many of the
warnings that are given turn out to be false alarms. A false alarm occurs
whenever a warning is sent, but it is not needed. This would nagate any safety
benefit of the system, and could even reduce the overall safety if warnings
become a distraction. In this paper, we propose our solution to address the
described problem; First, we briefly describe our method for estimating the
distribution of brake response times for a particular driver using data from a
Vehicular Ad-Hoc Network (VANET) system. Then, we investigate how brake
response times of individual drivers can be used in collision warning
algorithms to reduce false alarm rates while still maintaining a high level of
safety. This will yield a system that is overall more reliable and trustworthy
for drivers, which could lead to wider adoption and applicability for V2V/V2I
communication systems. Moreover, we show how false alarm rate varies with
respect to probability of accident. Our simulation results show that by
individualizing collision warnings the number of false alarms can be reduced
more than $50\%$. Then, we conclude safety applications could potentially take
full advantage of being customized to an individual's characteristics.


title: Magnetic Helicity and Large Scale Magnetic Fields: A Primer

abstract:
  Magnetic fields of laboratory, planetary, stellar, and galactic plasmas
commonly exhibit significant order on large temporal or spatial scales compared
to the otherwise random motions within the hosting system. Such ordered fields
can be measured in the case of planets, stars, and galaxies, or inferred
indirectly by the action of their dynamical influence, such as jets. Whether
large scale fields are amplified in situ or a remnant from previous stages of
an object's history is often debated for objects without a definitive magnetic
activity cycle. Magnetic helicity, a measure of twist and linkage of magnetic
field lines, is a unifying tool for understanding large scale field evolution
for both mechanisms of origin. Its importance stems from its two basic
properties: (1) magnetic helicity is typically better conserved than magnetic
energy; and (2) the magnetic energy associated with a fixed amount of magnetic
helicity is minimized when the system relaxes this helical structure to the
largest scale available. Here I discuss how magnetic helicity has come to help
us understand the saturation of and sustenance of large scale dynamos, the need
for either local or global helicity fluxes to avoid dynamo quenching, and the
associated observational consequences. I also discuss how magnetic helicity
acts as a hindrance to turbulent diffusion of large scale fields, and thus a
helper for fossil remnant large scale field origin models in some contexts. I
briefly discuss the connection between large scale fields and accretion disk
theory as well. The goal here is to provide a conceptual primer to help the
reader efficiently penetrate the literature.

categories: astro-ph.SR astro-ph.GA astro-ph.HE physics.plasm-ph physics.space-ph


title: Fragility Distributions and their approximations

abstract:
  Given a sequence of $n$ identically distributed random variables with common
distribution $F$, the \emph{fragility distribution of order $m$}, represented
by $\FD$, is the limit conditional distribution of the number of exceedances
given there are at least $m$ exceedances, as the threshold tends to the right
end point of $F$. In this paper we are concerned with the existence of $\FD$
and its asymptotic behaviour when $n$ becomes large. For a stationary sequence
with its exceedance process converging to a compound Poisson process, we derive
an explicit formula for calculating $\lim_{n \to \infty} \FD$. We also
establish Stein's method for estimating the errors involved in fragility
distribution approximations.


title:
Theoretical study of insulating mechanism in multi-orbital Hubbard
  models with a large spin-orbit coupling: Slater versus Mott scenario in
  Sr$_2$IrO$_4$

abstract:
  To examine the insulating mechanism of 5$d$ transition metal oxide
Sr$_2$IrO$_4$, we study the ground state properties of a three-orbital Hubbard
model with a large relativistic spin-orbit coupling on a square lattice. Using
a variational Monte Carlo method, we find that the insulating state appearing
in the ground state phase diagram for one hole per site varies from a weakly
correlated to a strongly correlated antiferromagnetic (AF) state with
increasing Coulomb interactions. This crossover is characterized by the
different energy gain mechanisms of the AF insulating state, i.e., from an
interaction-energy driven Slater-type insulator to a band-energy driven
Mott-type insulator with increasing Coulomb interactions. Our calculations
reveal that Sr$_2$IrO$_4$ is a "moderately correlated" AF insulator located in
the intermediate coupling region between a Slater-type and a Mott-type
insulators.


title: An Optimization Method For Slice Interpolation Of Medical Images

abstract:
  Slice interpolation is a fast growing field in medical image processing.
Intensity-based interpolation and object-based interpolation are two major
groups of methods in the literature. In this paper, we describe an
object-oriented, optimization method based on a modified version of
curvature-based image registration, in which a displacement field is computed
for the missing slice between two known slices and used to interpolate the
intensities of the missing slice. The proposed approach is evaluated
quantitatively by using the Mean Squared Difference (MSD) as a metric. The
produced results also show visual improvement in preserving sharp edges in
images.


title: Integrability as a consequence of discrete holomorphicity: loop models

abstract:
  In this paper, we explore the relationship between integrability and the
discrete holomorphicity of a class of complex lattice observables in the
context of the Potts dense loop model and the O(n) dilute loop model. It is
shown that the conditions for integrability, namely, the inversion and
Yang-Baxter relations, can be derived from the condition of holomorphicity of
the observables. Furthermore, the Z-invariance of the models is shown to result
in the invariance of the observables on the boundary of a sublattice under
reshuffling of the rhombuses of its planar rhombic embedding.


title: A generalization of a completeness lemma in minimal surface theory

abstract:
  We settle a question posed by Umehara and Yamada, which generalizes a
completeness lemma useful in differential geometry.


title: NCON: A tensor network contractor for MATLAB

abstract:
  A fundamental process in the implementation of any numerical tensor network
algorithm is that of contracting a tensor network. In this process, a network
made up of multiple tensors connected by summed indices is reduced to a single
tensor or a number by evaluating the index sums. This article presents a MATLAB
function ncon(), or "Network CONtractor", which accepts as its input a tensor
network and a contraction sequence describing how this network may be reduced
to a single tensor or number. As its output it returns that single tensor or
number. The function ncon() may be obtained by downloading the source of this
preprint.


title:
The observable signature of late heating of the Universe during cosmic
  reionization

abstract:
  Models and simulations of the epoch of reionization predict that spectra of
the 21-cm transition of atomic hydrogen will show a clear fluctuation peak, at
a redshift and scale, respectively, that mark the central stage of reionization
and the characteristic size of ionized bubbles. This is based on the assumption
that the cosmic gas was heated by stellar remnants - particularly X-ray
binaries - to temperatures well above the cosmic microwave background at that
time (~ 30 K). Here we show instead that the hard spectra (that is, spectra
with more high-energy photons than low-energy photons) of X-ray binaries make
such heating ineffective, resulting in a delayed and spatially uniform heating
that modifies the 21-cm signature of reionization. Rather than looking for a
simple rise and fall of the large-scale fluctuations (peaking at several
millikelvin), we must expect a more complex signal also featuring a distinct
minimum (at less than a millikelvin) that marks the rise of the cosmic mean gas
temperature above the microwave background. Observing this signal, possibly
with radio telescopes in operation today, will demonstrate the presence of a
cosmic background of hard X-rays at that early time.


title:
Dirac Cone Metric and the Origin of the Spin Connections in Monolayer
  Graphene

abstract:
  We show that the modulation of the hopping amplitudes in the honeycomb
lattice of the monolayer graphene uniquely defines a metric which corresponds
to the shape of the Dirac cone. The spin connection of this effective metric
field can be obtained from the microscopic tight-binding Hamiltonian exactly,
completing the analogy between the sublattice pseudospin travelling in the
monolayer graphene with ripples and strain fields, and the real spin $1/2$
fermion travelling in a curved space. The effective metric as seen by the
sublattice pseudospin is different from the real space metric as defined by the
two-dimensional manifold of the graphene monolayer. All relevant terms of the
effective gauge field from the microscopic model is calculated exactly for a
unimodular effective metric.


title: D-brane on Poisson manifold and Generalized Geometry

abstract:
  The properties of the D-brane fluctuations are investigated using the two
types of deformation of the Dirac structure, based on the B-transformation and
the beta-transformation, respectively. The former gives the standard gauge
theory with 2-form field strength. The latter gives a non-standard gauge theory
on the Poisson manifold with bivector field strength and the vector field as a
gauge potential, where the gauge symmetry is a diffeomorphism generated by the
Hamiltonian vector field. The map between the two gauge theories is also
constructed with the help of Moser's Lemma and the Magnus expansion. We also
investigate the relation to the gauge theory on the noncommutative D-branes.


title:
Galton-Watson Process for a class of distributions from Bernoulli to
  Poisson

abstract:
  In this paper the Galton Watson branching process has been studied for a
class of offspring distributions which are in a way sandwiched between the
Bernoulli and Poisson.