title: Binary Cepheids: Separations and Mass Ratios in $5\,M_\odot$ Binaries

abstract:
  Deriving the distribution of binary parameters for a particular class of
stars over the full range of orbital separations usually requires the
combination of results from many different observing techniques (radial
velocities, interferometry, astrometry, photometry, direct imaging), each with
selection biases. However, Cepheids---cool, evolved stars of $\sim$$5\,
M_\odot$---are a special case because ultraviolet spectra will immediately
reveal any companion star hotter than early type A, {\it regardless of the
orbital separation}. We have used {\it International Ultraviolet Explorer}
(\IUE) UV spectra of a complete sample of all 76 Cepheids brighter than V=8 to
create a list of {\it all 18} Cepheids with companions more massive than $2.0\,
M_\odot$. Orbital periods of many of these binaries are available from
radial-velocity studies, or can be estimated for longer-period systems from
detected velocity variability. In an imaging survey with the {\it Hubble Space
Telescope} Wide Field Camera 3, we resolved three of the companions (those of
$\eta$ Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods
out to the long-period end of the distribution. Combining these separations
with orbital data in the literature, we derive an unbiased distribution of
binary separations, orbital periods, and mass ratios. The distribution of
orbital periods shows that the $5\, M_\odot$ binaries have systematically
shorter periods than do $1\, M_\odot$ stars. Our data also suggest that the
distribution of mass ratios depends both on binary separation and system
multiplicity. The distribution of mass ratios as a function of orbital
separation, however, does not depend on whether a system is a binary or a
triple.


title: Self/anti-self charge conjugate states in the helicity basis

abstract:
  We construct self/anti-self charge conjugate (Majorana-like) states for the
(1/2,0)+(0,1/2) representation of the Lorentz group, and their analogs for
higher spins within the quantum field theory. The problem of the basis
rotations and that of the selection of phases in the Dirac-like and
Majorana-like field operators are considered. The discrete symmetries
properties (P, C, T) are studied. Particular attention has been paid to the
question of (anti)commutation of the Charge conjugation operator and the Parity
in the helicity basis. Dynamical equations have also been presented. In the
(1/2,0)+(0,1/2) representation they obey the Dirac-like equation with eight
components, which has been first introduced by Markov. Thus, the Fock space for
corresponding quantum fields is doubled (as shown by Ziino). The chirality and
the helicity for Dirac and Majorana states have been discussed. PACS: 11.30.Cp,
11.30.Er, 11.30.Ly Keywords: Lorentz Group, Neutral Particles, Helicity Basis


title:
Near-Extremal Black Hole Thermodynamics from AdS2/CFT1 Correspondence in
  The Low Energy Limit of 4D Heterotic String Theory

abstract:
  We compute the asymptotic symmetry group of the four dimensional
near-extremal Kerr-Sen black hole within an AdS2/CFT1 correspondence. We do
this by performing a Robinson-Wilczek two dimensional reduction and construct a
quantum theory of the remaining field content. The resulting energy momentum
tensor generates an asymptotic Virasoro algebra, to s-wave, with a calculable
central extension. This center in conjunction with the proper regularized
lowest Virasoro eigen-mode yields the near-extremal Kerr-Sen entropy via the
statistical Cardy formula. Finally we analyze quantum holomorphic fluxes of the
dual CFT giving rise to a finite Hawking temperature weighted by the central
charge of the near-extremal Kerr-Sen metric.


title:
Optimal Design and Analysis of the Exponentially Weighted Moving Average
  Chart for Exponential Data

abstract:
  We study optimal design of the Exponentially Weighted Moving Average (EWMA)
chart by a proper choice of the smoothing factor and the initial value
(headstart) of the decision statistic. The particular problem addressed is that
of quickest detection of an abrupt change in the parameter of a discrete-time
exponential model. Both pre- and post-change parameter values are assumed
known, but the change-point is not known. For this change-point detection
scenario, we examine the performance of the conventional one-sided EWMA chart
with respect to two optimality criteria: Pollak's minimax criterion associated
with the maximal conditional expected delay to detection and Shiryaev's
multi-cyclic setup associated with the stationary expected delay to detection.
Using the integral-equations approach, we derive the exact closed-form formulae
for all of the required performance measures. Based on these formulae we find
the optimal smoothing factor and headstart by solving the corresponding two
bivariate constraint optimization problems. Finally, the performance of the
optimized EWMA chart is compared against that of the Shiryaev--Roberts--$r$
procedure in the minimax setting, and against that of the original
Shiryaev--Roberts procedure in the multi-cyclic setting. The main conclusion is
that the EWMA chart, when fully optimized, turns out to be a very competitive
procedure, with performance nearly indistinguishable from that of the
known-to-be-best Shiryaev--Roberts--$r$ and Shiryaev--Roberts procedures.


title:
Man and Machine: Questions of Risk, Trust and Accountability in Today's
  AI Technology

abstract:
  Artificial Intelligence began as a field probing some of the most fundamental
questions of science - the nature of intelligence and the design of intelligent
artifacts. But it has grown into a discipline that is deeply entwined with
commerce and society. Today's AI technology, such as expert systems and
intelligent assistants, pose some difficult questions of risk, trust and
accountability. In this paper, we present these concerns, examining them in the
context of historical developments that have shaped the nature and direction of
AI research. We also suggest the exploration and further development of two
paradigms, human intelligence-machine cooperation, and a sociological view of
intelligence, which might help address some of these concerns.


title: Irreversible thermodynamics of creep in crystalline solids

abstract:
  We develop an irreversible thermodynamics framework for the description of
creep deformation in crystalline solids by mechanisms that involve vacancy
diffusion and lattice site generation and annihilation. The material undergoing
the creep deformation is treated as a non-hydrostatically stressed
multi-component solid medium with non-conserved lattice sites and
inhomogeneities handled by employing gradient thermodynamics. Phase fields
describe microstructure evolution which gives rise to redistribution of vacancy
sinks and sources in the material during the creep process. We derive a general
expression for the entropy production rate and use it to identify of the
relevant fluxes and driving forces and to formulate phenomenological relations
among them taking into account symmetry properties of the material. As a simple
application, we analyze a one-dimensional model of a bicrystal in which the
grain boundary acts as a sink and source of vacancies. The kinetic equations of
the model describe a creep deformation process accompanied by grain boundary
migration and relative rigid translations of the grains. They also demonstrate
the effect of grain boundary migration induced by a vacancy concentration
gradient across the boundary.


title:
An Architecture for Autonomously Controlling Robot with Embodiment in
  Real World

abstract:
  In the real world, robots with embodiment face various issues such as dynamic
continuous changes of the environment and input/output disturbances. The key to
solving these issues can be found in daily life; people `do actions associated
with sensing' and `dynamically change their plans when necessary'. We propose
the use of a new concept, enabling robots to do these two things, for
autonomously controlling mobile robots. We implemented our concept to make two
experiments under static/dynamic environments. The results of these experiments
show that our idea provides a way to adapt to dynamic changes of the
environment in the real world.


title:
Evolution of the mass, size, and star formation rate in high-redshift
  merging galaxies MIRAGE - A new sample of simulations with detailed stellar
  feedback

abstract:
  We aim at addressing the questions related to galaxy mass assembly through
major and minor wet merging processes in the redshift range 1<z<2. A consequent
fraction of Milky Way like galaxies are thought to have undergone an unstable
clumpy phase at this early stage. Using the adaptive mesh refinement code
RAMSES, with a recent physically-motivated implementation of stellar feedback,
we build the Merging and Isolated high-Redshift Adaptive mesh refinement
Galaxies (MIRAGE) sample. It is composed of 20 mergers and 3 isolated idealized
disks simulations with global physical properties in accordance with the 1<z<2
mass complete sample MASSIV. The numerical hydrodynamical resolution reaches 7
parsecs in the smallest Eulerian cells. Our simulations include: star
formation, metal line cooling, metallicity advection, and a recent
implementation of stellar feedback which encompasses OB-type stars radiative
pressure, photo-ionization heating, and supernovae. The initial conditions are
set to match the z~2 observations, thanks to a new public code DICE. The
numerical resolution allows us to follow the formation and evolution of giant
clumps formed in-situ from Jeans instabilities triggered by high initial gas
fraction. The star formation history of isolated disks shows stochastic star
formation rate, which proceeds from the complex behavior of the giant clumps.
Our minor and major gas-rich merger simulations do not trigger starbursts,
suggesting a saturation of the star formation in a turbulent and clumpy
interstellar medium fed by substantial accretion from the circum-galactic
medium. Our simulations are close to the normal regime of the disk-like star
formation on a Schmidt-Kennicutt diagram. The mass-size relation and its rate
of evolution matches observations, suggesting that the inside-out growth
mechanisms of the stellar disk do not necessarily require to be achieved
through a cold accretion.


title: Testing models of new physics with UHE air shower observations

abstract:
  Several air shower observatories have established that the number of muons
produced in UHE air showers is significantly larger than that predicted by
models. We argue that the only solution to this muon deficit, compatible with
the observed Xmax distributions, is to reduce the transfer of energy from the
hadronic shower into the EM shower, by reducing the production or decay of
pi0s. We present four different models of new physics, each with a theoretical
rationale, which can accomplish this. One has a pure proton composition and
three have mixed composition. Two entail new particle physics and suppress pi0
production or decay above LHC energies. The other two are less radical but
nonetheless require significant modifications to existing hadron production
models -- in one the changes are only above LHC energies and in the other the
changes extend to much lower energies. We show that the models have
distinctively different predictions for the correlation between the number of
muons at ground and Xmax in hybrid events, so that with future hybrid data it
should be possible to discriminate between models of new physics and
disentangle the particle physics from composition.


title: Extendable self-avoiding walks

abstract:
  The connective constant mu of a graph is the exponential growth rate of the
number of n-step self-avoiding walks starting at a given vertex. A
self-avoiding walk is said to be forward (respectively, backward) extendable if
it may be extended forwards (respectively, backwards) to a singly infinite
self-avoiding walk. It is called doubly extendable if it may be extended in
both directions simultaneously to a doubly infinite self-avoiding walk. We
prove that the connective constants for forward, backward, and doubly
extendable self-avoiding walks, denoted respectively by mu^F, mu^B, mu^FB,
exist and satisfy mu = mu^F = mu^B = mu^FB for every infinite, locally finite,
strongly connected, quasi-transitive directed graph. The proofs rely on a 1967
result of Furstenberg on dimension, and involve two different arguments
depending on whether or not the graph is unimodular.


title: Star formation in galaxies: the role of spiral arms

abstract:
  Studying star formation in spiral arms tells us not only about the evolution
of star formation, and molecular clouds, but can also tell us about the nature
of spiral structure in galaxies. I will address both these topics using the
results of recent simulations and observations. Galactic scale simulations are
beginning to examine in detail the evolution of GMCs as they form in spiral
arms, and then disperse by stellar feedback or shear. The overall timescale for
this process appears comparable to the crossing time of the GMCs, a few Myrs
for $10^5$ M$_{\odot}$ clouds, 20 Myr or so for more massive GMCs. Both
simulations and observations show that the massive clouds are found in the
spiral arms, likely as a result of cloud-cloud collisions. Simulations
including stars should also tell us about the stellar age distribution in GMCs,
and across spiral arms. More generally, recent work on spiral galaxies suggests
that the dynamics of gas flows in spiral arms are different in longlived and
transient spiral arms, resulting in different age patterns in the stars. Such
results could be used to help establish the main driver of spiral structure in
the Milky Way (Toomre instabilities, the bar, or nearby companion galaxies) in
conjunction with future surveys.


title: Line defects and (framed) BPS quivers

abstract:
  The BPS spectrum of certain N=2 supersymmetric field theories can be
determined algebraically by studying the representation theory of BPS quivers.
We introduce methods based on BPS quivers to study line defects. The presence
of a line defect opens up a new BPS sector: framed BPS states can be bound to
the defect. The defect can be geometrically described in terms of laminations
on a curve. To a lamination we associate certain elements of the Leavitt path
algebra of the BPS quiver and use them to compute the framed BPS spectrum. We
also provide an alternative characterization of line defects by introducing
framed BPS quivers. Using the theory of (quantum) cluster algebras, we derive
an algorithm to compute the framed BPS spectra of new defects from known ones.
Line defects are generated from a framed BPS quiver by applying certain
sequences of mutation operations. Framed BPS quivers also behave nicely under a
set of "cut and join" rules, which can be used to study how N=2 systems with
defects couple to produce more complicated ones. We illustrate our formalism
with several examples.


title:
Projected Performance of an Upgraded CMS Detector at the LHC and HL-LHC:
  Contribution to the Snowmass Process

abstract:
  The physics reach of the CMS detector achievable with 300(0) inverse
femtobarns of proton-proton collisions recorded at sqrt(s)=14 TeV is presented.
Ultimate precision on measurements of Higgs boson properties, top quark
physics, and electroweak processes are discussed, as well as the discovery
potential for new particles beyond the standard model. In addition, the
potential for future heavy ion physics is presented. This document has been
submitted as a white paper to the Snowmass process, an exercise initiated by
the American Physical Society's Division of Particles and Fields to assess the
long-term physics aspirations of the US high energy physics community.


title:
The long lives of giant clumps and the birth of outflows in gas-rich
  galaxies at high redshift

abstract:
  Star-forming disk galaxies at high redshift are often subject to violent disk
instability, characterized by giant clumps whose fate is yet to be understood.
The main question is whether the clumps disrupt within their dynamical
timescale (<50Myr), like molecular clouds in today's galaxies, or whether they
survive stellar feedback for more than a disk orbital time (~300Myr) in which
case they can migrate inward and help building the central bulge. We present
3.5-7pc resolution AMR simulations of high-redshift disks including
photo-ionization, radiation pressure, and supernovae feedback (Renaud et al.
2013, and Perret et al., this astro-ph issue). Our modeling of radiation
pressure determines the mass loading and initial velocity of winds from basic
physical principles. We find that the giant clumps produce steady outflow rates
comparable to and sometimes somewhat larger than their star formation rate,
with velocities largely sufficient to escape galaxy. The clumps also lose mass,
especially old stars, by tidal stripping, and the stellar populations contained
in the clumps hence remain relatively young (<=200Myr), as observed. The clumps
survive gaseous outflows and stellar loss, because they are wandering in
gas-rich turbulent disks from which they can re-accrete gas at high rates
compensating for outflows and tidal stripping, overall keeping realistic and
self-regulated gaseous and stellar masses. Our simulations produce gaseous
outflows with velocities, densities and mass loading consistent with
observations, and at the same time suggest that the giant clumps survive for
hundreds of Myr and complete their migration to the center of high-redshift
galaxies, without rapid dispersion and reformation of clumps.


title: The mixing time of the fifteen puzzle

abstract:
  We show that there are universal positive constants c and C such that the
mixing time T_{mix} for the fifteen puzzle in an n by n torus satisfies cn^4
log n < T_{mix} < Cn^4 log^2 n.


title: Reconstruction of Network Coded Sources From Incomplete Datasets

abstract:
  In this paper, we investigate the problem of recovering source information
from an incomplete set of network coded data. We first study the theoretical
performance of such systems under maximum a posteriori (MAP) decoding and
derive the upper bound on the probability of decoding error as a function of
the system parameters. We also establish the sufficient conditions on the
number of network coded symbols required to achieve decoding error probability
below a certain level. We then propose a low complexity iterative decoding
algorithm based on message passing for decoding the network coded data of a
particular class of statistically dependent sources that present pairwise
linear correlation. The algorithm operates on a graph that captures the network
coding constraints, while the knowledge about the source correlation is
directly incorporated in the messages exchanged over the graph. We test the
proposed method on both synthetic data and correlated image sequences and
demonstrate that the prior knowledge about the source correlation can be
effectively exploited at the decoder in order to provide a good reconstruction
of the transmitted data in cases where the network coded data available at the
decoder is not sufficient for exact decoding.


title:
Dynamical Fragmentation of the T Pyxidis Nova Shell During Recurrent
  Eruptions

abstract:
  Hubble Space Telescope} images of the ejecta surrounding the nova T Pyxidis
resolve the emission into more than two thousand bright knots. We simulate the
dynamical evolution of the ejecta from T Pyxidis during its multiple eruptions
over the last 150 years using the adaptive mesh refinement capability of the
gas dynamics code Ramses. We demonstrate that the observed knots are the result
of Richtmeyer-Meshkov gas dynamical instabilities (the equivalent of
Rayleigh-Taylor instabilities in an accelerated medium). These instabilities
are caused by the overrunning of the ejecta from the classical nova of 1866 by
fast moving ejecta from the subsequent six recurrent nova outbursts. The model
correctly predicts the observed expansion and dimming of the T Pyx ejecta as
well as the knotty morphology. The model also predicts that deeper, high
resolution imagery will show filamentary structure connecting the knots. We
show reprocessed Hubble Space Telescope imagery that shows the first hints of
such structure.


title:
Parameters of the Menzerath-Altmann law: Statistical mechanical
  interpretation as applied to a linguistic organization

abstract:
  The distribution behavior dictated by the Menzerath-Altmann (MA) law is
frequently encountered in linguistic and natural organizations at various
structural levels. The mathematical form of this empirical law comprises three
fitting parameters whose values tend to be elusive, especially in
inter-organizational studies. To allow interpretation of these parameters and
better understand such distribution behavior, we present a statistical
mechanical approach based on an analogy between the classical particles of a
statistical mechanical organization and the number of distinct words in a
textual organization. With this derivation, we achieve a transformed
(generalized) form of the MA model, termed the statistical mechanical
Menzerath-Altmann (SMMA) model. This novel transformed model consists of four
parameters, one of which is a structure-dependent input parameter, and three of
which are free-fitting parameters. Using distinct word data sets from two text
corpora, we verified that the SMMA model describes the same distribution as the
MA model. We propose that the additional structure-dependent parameter of the
SMMA model converts the three fitting parameters into structure-independent
parameters. Moreover, the parameters of the SMMA model are associated with a
corresponding physical interpretation that can lead to characterization of an
organization' s thermodynamic properties. We also propose that many
organizations presenting MA law behavior, whether linguistic or not, can be
examined by the SMMA distribution model through the properly defined structural
degeneracy parameter and the energy associated states.


title: Influence of Culture on e-Government Acceptance in Saudi Arabia

abstract:
  The main purpose of this research is to determine the influence of culture on
e-government (electronic government) acceptance in the Kingdom of Saudi Arabia
(KSA). Citizens' transactional interactions (electronic transactions or
e-transactions) with the government via the Internet are examined. Multiple
models and theories in extant literature were referred to in identifying the
research context requirements that enabled the analysis of e-transaction
acceptance. A new research model that fits the research context was developed
to predict and explain how acceptance is affected. A sample of 671 Saudi
citizens was recruited using an online survey. Structural equation modelling
was used to assess the impact on intention to use e-transactions. Preference
for using e-transactions as a communication method, perceptions of the
compatibility of e-transactions with values and citizens' needs,
communicability of the results of using e-transactions, trust in the Internet
as a medium of communication with the government, and conservation values are
positive significant determinants of e-transaction acceptance. Conversely, the
influence of trust in government agencies and motivation towards gaining
prestige and possessing dominance over people and resources was negative. The
findings of this study include design and implementation strategies that can
serve as guidance for the Saudi government, as well as for the developers and
implementers of e-transactions in the KSA.


title: Temporal influence over the Last.fm social network

abstract:
  Several recent results show the influence of social contacts to spread
certain properties over the network, but others question the methodology of
these experiments by proposing that the measured effects may be due to
homophily or a shared environment. In this paper we justify the existence of
the social influence by considering the temporal behavior of Last.fm users. In
order to clearly distinguish between friends sharing the same interest,
especially since Last.fm recommends friends based on similarity of taste, we
separated the timeless effect of similar taste from the temporal impulses of
immediately listening to the same artist after a friend. We measured strong
increase of listening to a completely new artist in a few hours period after a
friend compared to non-friends representing a simple trend or external
influence. In our experiment to eliminate network independent elements of
taste, we improved collaborative filtering and trend based methods by blending
with simple time aware recommendations based on the influence of friends. Our
experiments are carried over the two-year "scrobble" history of 70,000 Last.fm
users.


title: Signal Velocity in Oscillator Networks

abstract:
  We investigate a system of coupled oscillators on the circle, which arises
from a simple model for behavior of large numbers of autonomous vehicles. The
model considers asymmetric, linear, decentralized dynamics, where the
acceleration of each vehicle depends on the relative positions and velocities
between itself and a set of local neighbors. We first derive necessary and
sufficient conditions for asymptotic stability, then derive expressions for the
phase velocity of propagation of disturbances in velocity through this system.
We show that the high frequencies exhibit damping, which implies existence of
well-defined signal velocities $c_+>0$ and $c_-<0$ such that low frequency
disturbances travel through the flock as $f(x-c_+t)$ in the direction of
increasing agent numbers and $f(x-c_-t)$ in the other.


title: Flavor of Gluino Decay in High-Scale Supersymmetry

abstract:
  The discovery of the Higgs boson with a mass of about 125 GeV intimates us a
possibility of a high-scale supersymmetry (SUSY) breaking model, where a
sfermion mass scale is much higher than the electroweak scale. Although a
general SUSY standard model can contribute to the low-energy flavor and/or
CP-violating processes, the high-scale SUSY breaking model provides smaller
signatures and therefore are less constrained, even in the presence of large
flavor/CP violations of sfermions. However, a manner of gluino decay directly
reflects the squark flavor structure and provides us a clue for the sfermion
flavor structure. In this paper, we study the gluino decay in detail and
discuss the interplay with the gluino decay and low-energy flavor and CP
observation.


title: A Bayesian Approach to Deriving Ages of Individual Field White Dwarfs

abstract:
  We apply a self-consistent and robust Bayesian statistical approach to
determining the ages, distances, and ZAMS masses of 28 field DA white dwarfs
with ages of approximately 4 to 8 Gyrs. Our technique requires only quality
optical and near-IR photometry to derive ages with < 15% uncertainties,
generally with little sensitivity to our choice of modern initial-final mass
relation. We find that age, distance, and ZAMS mass are correlated in a manner
that is too complex to be captured by traditional error propagation techniques.
We further find that the posterior distributions of age are often asymmetric,
indicating that the standard approach to deriving WD ages can yield misleading
results.


title: Twin Peak Higgs

abstract:
  A broad class of models in which electroweak symmetry breaking originates
from dynamics in a singlet dark sector, and is transferred to the Standard
Model via the Higgs portal, predicts in general strongly suppressed Higgs boson
mixing with a singlet scalar. In this work we point out that at present this
class of models allows for the second phenomenologically acceptable solution
with almost maximal mixing between the Higgs and the scalar singlet. This
scenario predicts an almost degenerate twin peak Higgs signal which is
presently indistinguishable from a single peak, due to the limited LHC mass
resolution. Because of that, the LHC experiments measure inclusive Higgs rates
that all must exactly agree with Standard Model predictions due to sum rules.
We show that if the dark sector and Standard Model communicate only via the
singlet messenger scalar that mixes with the Higgs, the spin independent direct
detection cross section of dark matter is suppressed by the scalar mass
degeneracy, explaining its non-observation so far.


title: A Simple Phenomenological Model for Grain Clustering in Turbulence

abstract:
  We propose a simple model for density fluctuations of aerodynamic grains,
embedded in a turbulent, gravitating gas disk. The model combines a calculation
for the behavior of a group of grains encountering a single turbulent eddy,
with a hierarchical approximation of the eddy statistics. This makes analytic
predictions for a range of quantities including: distributions of grain
densities, power spectra and correlation functions of fluctuations, and maximum
grain densities reached. We predict how these scale as a function of grain drag
time t_stop, spatial scale, grain-to-gas mass ratio, strength of turbulence
(alpha), and detailed disk properties. We test these against numerical
simulations with various turbulence-driving mechanisms. The simulations agree
well with the predictions, spanning t_stop*Omega ~ 1e-4 - 10, alpha ~ 1e-10 -
1e-2, and grain-to-gas mass ratio ~0-3. Results from 'turbulent concentration'
simulations and laboratory experiments are also predicted as a special case.
Vortices on a wide range of scales disperse and concentrate grains
hierarchically. For small grains this is most efficient in eddies with turnover
time comparable to the stopping time, but fluctuations are also damped by local
gas-grain drift. For large grains, shear and gravity lead to a much broader
range of eddy scales driving fluctuations, with most power on the largest
scales. The grain density distribution has a log-Poisson shape, with
fluctuations for large grains up to factors >1000. We provide simple analytic
expressions for the predictions, and discuss implications for planetesimal
formation, grain growth, and the structure of turbulence.

categories: astro-ph.EP astro-ph.GA physics.ao-ph physics.flu-dyn


title:
The Massive Star Population in M101. I. The Identification and Spatial
  Distribution of the Visually Luminous Stars

abstract:
  An increasing number of non-terminal giant eruptions are being observed by
modern supernova and transient surveys. But very little is known about the
origin of these giant eruptions and their progenitors, many of which are
presumably very massive, evolved stars. Motivated by the small number of
progenitors positively associated with these giant eruptions, we have begun a
survey of the evolved massive star populations in nearby galaxies. The nearby,
nearly face on, giant spiral M101 is an excellent laboratory for studying a
large population of very massive stars. In this paper, we present BVI
photometry obtained from archival HST/ACS WFC images of M101. We have produced
a catalog of luminous stars with photometric errors <10% for V < 24.5 and 50%
completeness down to V ~ 26.5 even in regions of high stellar crowding. Using
color and luminosity criteria we have identified candidate luminous OB type
stars and blue supergiants, yellow supergiants, and red supergiants for future
observation. We examine their spatial distributions across the face of M101 and
find that the ratio of blue to red supergiants decreases by two orders of
magnitude over the radial extent of M101 corresponding to 0.5 dex in
metallicity. We discuss the resolved stellar content in the giant star forming
complexes NGC 5458, 5453, 5461, 5451, 5462, and 5449 and discuss their
color-magnitude diagrams in conjunction with the spatial distribution of the
stars to determine their spatio-temporal formation histories.


title: Sensitivity of potential future $pp$ colliders to quark compositeness

abstract:
  A study is presented of the sensitivity of potential future $pp$ colliders to
quark compositeness. The analysis uses normalized dijet angular distributions
compared to expectations from leading-order contact interaction models.


title:
$F(R)$ nonlinear massive theories of gravity and their cosmological
  implications

abstract:
  We propose a nonlinear massive gravitational theory which includes $F(R)$
modifications. This construction inherits the benefits of the de
Rham-Gabadadze-Tolley model and is free of the Boulware-Deser ghost due to the
existence of a Hamiltonian constraint accompanied by a nontrivial secondary
one. The scalar perturbations in a cosmological background can be stabilized at
the linear level for a wide class of the $F(R)$ models. The linear scalar mode
arisen from the $F(R)$ sector can absorb the nonlinear longitudinal graviton,
and hence, our scenario demonstrates the possibility of a gravitational
Goldstone theorem. Finally, due to the combined contribution of the $F(R)$ and
graviton-mass sectors, the proposed theory allows for a large class of
cosmological evolutions, such as the simultaneous and unified description of
inflation and late-time acceleration.


title: Root Systems In Finite Symplectic Vector Spaces

abstract:
  We study subsets in possibly degenerate symplectic vector spaces over finite
fields, which are stable under a given Coxeter/Weyl reflection group. These
symplectic root systems provide crucial combinatorical data to classify
finite-dimensional Nichols algebras for nilpotent groups G over the complex
numbers [Len13a], where the symplectic form is given by the group's commutator
map. For example, the degree of degeneracy of the symplectic root system
determines the size of the center of G.
  In this article we classify symplectic root systems over the finite field
F_2, where symplectic just means isotropic. We prove that every Dynkin diagram
admits, up to symplectic isomorphisms, a unique minimal symplectic root system
over F_2 and thus requires a specific degree of degeneracy of the symplectic
vector space. Any non-minimal symplectic root system turns out to be a quotient
of a minimal one by a universal property. As examples and for further
applications we explicitly construct all symplectic root systems for Cartan
matrices resp. Dynkin diagrams of type ADE.


title: Bremsstrahlung gamma rays from light Dark Matter

abstract:
  We discuss the often-neglected role of bremsstrahlung processes on the
interstellar gas in computing indirect signatures of Dark Matter (DM)
annihilation in the Galaxy, particularly for light DM candidates in the
phenomenologically interesting O(10) GeV mass range. Especially from directions
close to the Galactic Plane, the expected gamma-ray spectrum is altered via two
effects: directly, by the photons emitted in the bremsstrahlung process on the
interstellar gas by energetic electrons which are among the DM annihilation
byproducts; indirectly, by the modification of the same electron spectrum, due
to the additional energy loss process in the diffusion-loss equation (e.g. the
resulting inverse Compton emission is altered). We quantify the importance of
the bremsstrahlung emission in the GeV energy range, showing that it is the
dominant component of the gamma-ray spectrum for some cases. We also find that,
in regions in which bremsstrahlung dominates energy losses, the related
gamma-ray emission is only moderately sensitive to possible large variations in
the gas density. Still, we stress that, for computing precise spectra in the
(sub-)GeV range, it is important to obtain a reliable description of the inner
Galaxy gas distribution as well as to compute self-consistently the gamma
emission and the solution to the diffusion-loss equation. For example, these
are crucial issues to quantify and interpret meaningfully gamma-ray map
`residuals' in terms of (light) DM annihilations.


title:
A Near-Infrared Spectroscopic Study of Young Field Ultracool Dwarfs:
  Additional Analysis

abstract:
  We present additional analysis of the classification system presented in
Allers & Liu (2013). We refer the reader to Allers & Liu (2013) for a detailed
discussion of our near-IR spectral type and gravity classification system.
Here, we address questions and comments from participants of the Brown Dwarfs
Come of Age meeting. In particular, we examine the effects of binarity and
metallicity on our classification system. We also present our classification of
Pleiades brown dwarfs using published spectra. Lastly, we determine SpTs and
calculate gravity-sensitive indices for the BT-Settl atmospheric models and
compare them to observations.


title: Fast Polar Decoders: Algorithm and Implementation

abstract:
  Polar codes provably achieve the symmetric capacity of a memoryless channel
while having an explicit construction. This work aims to increase the
throughput of polar decoder hardware by an order of magnitude relative to the
state of the art successive-cancellation decoder. We present an algorithm,
architecture, and FPGA implementation of a gigabit-per-second polar decoder.


title:
Orientation Dependence of the Critical Magnetic Field for Multiferroic
  BiFeO$_3$

abstract:
  Multiferroic BiFeO3 undergoes a transition from a distorted spiral phase to a
G-type antiferromagnet above a critical field H_c that depends on the
orientation m of the field. We show that H_c(m) has a maximum when oriented
along a cubic diagonal parallel to the electric polarization P and a minimum in
the equatorial plane normal to P when two magnetic domains with the highest
critical fields are degenerate. The measured critical field along a cubic axis
is about 19 T but H_c is predicted to vary by as much as 2.5 T above and below
this value. The orientational dependence of H_c(m) is more complex than
indicated by earlier work, which did not consider the competition between
magnetic domains.


title: Four-Color Stimulated Optical Forces for Atomic and Molecular Slowing

abstract:
  Stimulated optical forces offer a simple and efficient method for providing
optical forces far in excess of the saturated radiative force. The bichromatic
force, using a counterpropagating pair of two-color beams, has so far been the
most effective of these stimulated forces for deflecting and slowing atomic
beams. We have numerically studied the evolution of a two-level system under
several different bichromatic and polychromatic light fields, while retaining
the overall geometry of the bichromatic force. New insights are gained by
studying the time-dependent trajectory of the Bloch vector, including a better
understanding of the remarkable robustness of bi- and polychromatic forces with
imbalanced beam intensities. We show that a four-color polychromatic force
exhibits great promise. By adding new frequency components at the third
harmonic of the original bichromatic detuning, the force is increased by nearly
50% and its velocity range is extended by a factor of three, while the required
laser power is increased by only 33%. The excited-state fraction, crucial to
possible application to molecules, is reduced from 41% to 24%. We also discuss
some important differences between polychromatic forces and pulse trains from a
high-repetition-rate laser.


title:
The generalized scaling relations for X-ray galaxy clusters: the most
  powerful mass proxy

abstract:
  The application to observational data of the generalized scaling relations
(gSR) presented in Ettori et al. (2012) is here discussed. We extend further
the formalism of the gSR in the self-similar model for X-ray galaxy clusters,
showing that for a generic relation M_tot ~ L^a M_g^b T^c, where L, M_g and T
are the gas luminosity, mass and temperature, respectively, the values of the
slopes lay in the plane 4*a+3*b+2*c=3. Using published dataset, we show that
some projections of the gSR are the most efficient relations, holding among
observed physical X-ray quantities, to recover the cluster mass. This
conclusion is based on the evidence that they provide the lowest chi^2, the
lowest total scatter and the lowest intrinsic scatter among the studied scaling
laws on both galaxy group and cluster mass scales. By the application of the
gSR, the intrinsic scatter is reduced in all the cases down to a relative error
on M_tot below 16 per cent. The best-fit relations are: M_tot ~ M_g^a
T^{1.5-1.5a}, with a~0.4, and M_tot ~ L^a T^{1.5-2a}, with a~0.15. As a by
product of this study, we provide the estimates of the gravitating mass at
Delta=500 for 120 objects (50 from the Mahdavi et al. 2013 sample, 16 from
Maughan 2012; 31 from Pratt et al. 2009; 23 from Sun et al. 2009), 114 of which
are unique entries. The typical relative error in the mass provided from the
gSR only (i.e. not propagating any uncertainty associated with the observed
quantities) ranges between 3-5 per cent on cluster scale and is about 10 per
cent for galaxy groups. With respect to the hydrostatic values used to
calibrate the gSR, the masses are recovered with deviations in the order of 10
per cent due to the different mix of relaxed/disturbed objects present in the
considered samples. In the extreme case of a gSR calibrated with relaxed
systems, the hydrostatic mass in disturbed objects is over-estimated by about
20 per cent.


title:
Gradient estimates of harmonic functions and transition densities for
  Levy processes

abstract:
  We prove gradient estimates for harmonic functions with respect to a
$d$-dimensional unimodal pure-jump Levy process under some mild assumptions on
the density of its Levy measure. These assumptions allow for a construction of
an unimodal Levy process in $\R^{d+2}$ with the same characteristic exponent as
the original process. The relationship between the two processes provides a
fruitful source of gradient estimates of transition densities. We also
construct another process called a difference process which is very useful in
the analysis of differential properties of harmonic functions.


title:
MacWilliams Extension Theorems and the Local-Global Property for Codes
  over Rings

abstract:
  The MacWilliams extension theorem is investigated for various weight
functions over finite Frobenius rings. The problem is reformulated in terms of
a local-global property for subgroups of the general linear group. Among other
things, it is shown that the extension theorem holds true for poset weights if
and only if the underlying poset is hierarchical. Specifically, the
Rosenbloom-Tsfasman weight for vector codes satisfies the extension theorem,
whereas the Niederreiter-Rosenbloom-Tsfasman weight for matrix codes does not.
A short character-theoretic proof of the well-known MacWilliams extension
theorem for the homogeneous weight is provided. Moreover it is shown that the
extension theorem carries over to direct products of weights, but not to
symmetrized products.


title:
Instrumentation for laser physics and spectroscopy using 32-bit
  microcontrollers with an Android tablet interface

abstract:
  Several high-performance lab instruments suitable for manual assembly have
been developed using low-pin-count 32-bit microcontrollers that communicate
with an Android tablet via a USB interface. A single Android tablet app
accommodates multiple interface needs by uploading parameter lists and
graphical data from the microcontrollers, which are themselves programmed with
easily-modified C code. The hardware design of the instruments emphasizes low
chip counts and is highly modular, relying on small "daughter boards" for
special functions such as USB power management, waveform generation, and
phase-sensitive signal detection. In one example, a daughter board provides a
complete waveform generator and direct digital synthesizer that fits on a 1.5"
X 0.8" circuit card.


title: A Systematic Search for Trojan Planets in the Kepler data

abstract:
  Trojans are circumstellar bodies that reside in characteristic 1:1 orbital
resonances with planets. While all the trojans in our Solar System are small (<
~100 km), stable planet-size trojans may exist in extrasolar planetary systems,
and the Kepler telescope constitutes a formidable tool to search for them. Here
we report on a systematic search for extrasolar trojan companions to 2244 known
Kepler Objects of Interest (KOIs), with epicyclic orbital characteristics
similar to those of the Jovian trojan families. No convincing trojan candidates
are found, despite a typical sensitivity down to Earth-size objects. This fact
can however not be used to stringently exclude the existence of trojans in this
size range, since stable trojans need not necessarily share the same orbital
plane as the planet, and thus may not transit. Following this reasoning, we
note that if Earth-sized trojans exist at all, they are almost certainly both
present and in principle detectable in the full set of Kepler data, although a
very substantial computational effort would be required to detect them. On the
same token, we also note that some of the existing KOIs could in principle be
trojans themselves, with a primary planet orbiting outside of the transiting
plane. A few examples are given for which this is a readily testable scenario.


title: Ferro-orbital ordering transition in iron telluride Fe$_{1+y}$Te

abstract:
  Fe$_{1+y}$Te with $y \lesssim 0.05$ exhibits a first-order phase transition
on cooling to a state with a lowered structural symmetry, bicollinear
antiferromagnetic order, and metallic conductivity, $d\rho/dT > 0$. Here, we
study samples with $y = 0.09(1)$, where the frustration effects of the
interstitial Fe decouple different orders, leading to a sequence of
transitions. While the lattice distortion is closely followed by
\emph{incommensurate} magnetic order, the development of \emph{bicollinear}
order and metallic electronic coherence is uniquely associated with a separate
hysteretic first-order transition, at a markedly lower temperature, to a phase
with dramatically enhanced bond-order wave (BOW) order. The BOW state suggests
ferro-orbital ordering, where electronic delocalization in ferromagnetic zigzag
chains decreases local spin and results in metallic transport.


title: Resolution of Kantor and Babcock-Bergman Emission Theory Anomalies

abstract:
  Kantor's 1962 interferometer result supporting the emission theory of light
was tested by Babcock and Bergman in 1964 but with rotating glass plates placed
in a vacuum. The results falsified the theory that light passing out of the
glass continued at greater than c in the lab frame, but the anomalies were not
resolved. We review these anomalies as well as related and poorly understood
effects including kinetic reverse refraction and non-linear optics. We also
consider advances in science and astrophysics and find and describe a
theoretical resolution. We find that Kantor's finding may also be apparent
without violating the postulates of Special Relativity or invoking an absolute
'ether' frame. Relationships between Maxwell's near field transition zone,
photo-ionization, non-linear optics and the surface electro/magneto-optic Kerr
effects emerge, building an ontological construction which we describe and
quantify. Proper time is found to be required for proper speed. A relativistic
theoretical model is built from a diffractive mechanism, as used by the US
Naval Observatory for accuracy in the AA2010 aberration declination model, but
now with a consistent relativistic theory to support the model. We show how the
inconsistency between Michelson's 1924 experiment supporting ether and his
famous null result may arise from systemic asymmetry of crossing counts. The
quantum mechanisms of Raman scattering, optical axis rotation, and CMB frames
last scattered are shown to directly derive the Special Relativity postulates.


title: On the Scalability of Reliable Data Transfer in High Speed Networks

abstract:
  This paper considers reliable data transfer in a high-speed network (HSN) in
which the per-connection capacity is very large. We focus on sliding window
protocols employing selective repeat for reliable data transfer and study two
reliability mechanisms based on ARQ and FEC. The question we ask is which
mechanism is more suitable for an HSN in which the scalability of reliable data
transfer in terms of receiver's buffer requirement and achievable delay and
throughput is a concern. To efficiently utilize the large bandwidth available
to a connection in an HSN, sliding window protocols require a large
transmission window. In this regime of large transmission windows, we show that
while both mechanisms achieve the same asymptotic throughput in the presence of
packet losses, their delay and buffer requirements are different. Specifically,
an FEC-based mechanism has delay and receiver's buffer requirement that are
asymptotically smaller than that of an ARQ-based selective repeat mechanism by
a factor of log W, where W is the window size of the selective repeat
mechanism. This result is then used to investigate the implications of each
reliability mechanism on protocol design in an HSN in terms of throughput,
delay, buffer requirement, and control overhead.


title: Branes as solutions of gauge theories in gravitational field

abstract:
  The idea of the Gauss map is unified with the concept of branes as
hypersurfaces embedded into $D$-dimensional Minkowski space. The map introduces
new generalized coordinates of branes alternative to their world vectors
$\mathbf{x}$ and identified with the gauge and other massless fields. In these
coordinates the Dirac $p$-branes realize extremals of the Euler-Lagrange
equations of motion of a $(p+1)$-dimensional $SO(D-p-1)$ gauge-invariant action
in a gravitational background


title:
Monte-Carlo simulations of the dissipative random transverse-field Ising
  chain

abstract:
  We study the influence of Ohmic dissipation on the random transverse-field
Ising chain by means of large-scale Monte-Carlo simulations. To this end, we
first map the Hamiltonian onto a classical Ising model with long-range
$1/\tau^2$ interaction in the time-like direction. We then apply the highly
efficient cluster algorithm proposed by Luijten and Bl\"ote for system with
long-range interactions. Our simulations show that Ohmic dissipation destroys
the infinite-randomness quantum critical point of the dissipationless system.
Instead, the quantum phase transition between the paramagnetic and
ferromagnetic phases is smeared. We compare our results to recent predictions
of a strong-disorder renormalization group approach, and we discuss
generalizations to higher dimensions as well as experiments.


title:
Odd and even Kondo effects from emergent localisation in quantum point
  contacts

abstract:
  A quantum point contact (QPC) is a very basic nano-electronic device: a short
and narrow transport channel between two electron reservoirs. In clean channels
electron transport is ballistic and the conductance $G$ is then quantised as a
function of channel width with plateaus at integer multiples of $2e^2/h$ ($e$
is the electron charge and $h$ Planck's constant). This can be understood in a
picture where the electron states are propagating waves, without need to
account for electron-electron interactions. Quantised conductance could thus be
the signature of ultimate control over nanoscale electron transport. However,
even studies with the cleanest QPCs generically show significant anomalies on
the quantised conductance traces and there is consensus that these result from
electron many-body effects. Despite extensive experimental and theoretical
studies understanding of these anomalies is an open problem. We report evidence
that the many-body effects have their origin in one or more spontaneously
localised states that emerge from Friedel oscillations in the QPC channel.
Kondo physics will then also contribute to the formation of the many-body state
with Kondo signatures that reflect the parity of the number of localised
states. Evidence comes from experiments with length-tunable QPCs that show a
periodic modulation of the many-body physics with Kondo signatures of
alternating parity. Our results are of importance for assessing the role of
QPCs in more complex hybrid devices and proposals for spintronic and quantum
information applications. In addition, our results show that tunable QPCs offer
a rich platform for investigating many-body effects in nanoscale systems, with
the ability to probe such physics at the level of a single site.


title: The Necessity of Nowhere Equivalence

abstract:
  We prove some regularity properties (convexity, closedness, compactness and
preservation of upper hemicontinuity) for distribution and regular conditional
distribution of correspondences under the nowhere equivalence condition. We
show the necessity of such a condition for any of these properties to hold. As
an application, we demonstrate that the nowhere equivalence condition is
satisfied on the underlying agent space if and only if pure-strategy Nash
equilibria exist in general large games with any fixed uncountable compact
action space.


title: Quantum Corrections in Massive Gravity

abstract:
  We compute the one-loop quantum corrections to the potential of ghost-free
massive gravity. We show how the mass of external matter fields contribute to
the running of the cosmological constant, but do not change the ghost-free
structure of the massive gravity potential at one-loop. When considering
gravitons running in the loops, we show how the structure of the potential gets
destabilized at the quantum level, but in a way which would never involve a
ghost with a mass smaller than the Planck scale. This is done by explicitly
computing the one-loop effective action and supplementing it with the
Vainshtein mechanism. We conclude that to one-loop order the special mass
structure of ghost-free massive gravity is technically natural.


title:
Decentralized Multi-Robot Encirclement of a 3D Target with Guaranteed
  Collision Avoidance

abstract:
  We present a control framework for achieving encirclement of a target moving
in 3D using a multi-robot system. Three variations of a basic control strategy
are proposed for different versions of the encirclement problem, and their
effectiveness is formally established. An extension ensuring maintenance of a
safe inter-robot distance is also discussed. The proposed framework is fully
decentralized and only requires local communication among robots; in
particular, each robot locally estimates all the relevant global quantities. We
validate the proposed strategy through simulations on kinematic point robots
and quadrotor UAVs, as well as experiments on differential-drive wheeled mobile
robots.


title: The Resource Theory of Stabilizer Computation

abstract:
  Recent results on the non-universality of fault-tolerant gate sets underline
the critical role of resource states, such as magic states, to power scalable,
universal quantum computation. Here we develop a resource theory, analogous to
the theory of entanglement, for resources for stabilizer codes. We introduce
two quantitative measures - monotones - for the amount of non-stabilizer
resource. As an application we give absolute bounds on the efficiency of magic
state distillation. One of these monotones is the sum of the negative entries
of the discrete Wigner representation of a quantum state, thereby resolving a
long-standing open question of whether the degree of negativity in a
quasi-probability representation is an operationally meaningful indicator of
quantum behaviour.


title: Structure and Dynamics of Coauthorship, Citation, and Impact within CSCW

abstract:
  CSCW has stabilized as an interdisciplinary venue for computer, information,
cognitive, and social scientists but has also undergone significant changes in
its format in recent years. This paper uses methods from social network
analysis and bibliometrics to re-examine the structures of CSCW a decade after
its last systematic analysis. Using data from the ACM Digital Library, we
analyze changes in structures of coauthorship and citation between 1986 and
2013. Statistical models reveal significant but distinct patterns between
papers and authors in how brokerage and closure in these networks affects
impact as measured by citations and downloads. Specifically, impact is unduly
influenced by structural position, such that ideas introduced by those in the
core of the CSCW community (e.g., elite researchers) are advantaged over those
introduced by peripheral participants (e.g., newcomers). This finding is
examined in the context of recent changes to the CSCW conference that may have
the effect of upsetting the preference for contributions from the core.


title: Memory Effects in the Electron Glass

abstract:
  We investigate theoretically the slow non-exponential relaxation dynamics of
the electron glass out of equilibrium, where a sudden change in carrier density
reveals interesting memory effects. The self-consistent model of the dynamics
of the occupation numbers in the system successfully recovers the general
behavior found in experiments. Our numerical analysis is consistent with both
the expected logarithmic relaxation and our understanding of how increasing
disorder or interaction slows down the relaxation process, thus yielding a
consistent picture of the electron glass. We also present a novel finite size
"domino" effect where the connection to the leads affects the relaxation
process of the electron glass in mesoscopic systems. This effect speeds up the
relaxation process, and even reverses the expected effect of interaction;
stronger interaction then leading to a faster relaxation.


title:
A SCUBA-2 850 micron survey of protoplanetary discs in the sigma Orionis
  cluster

abstract:
  We present the results from a large 850 micron survey of the sigma Orionis
cluster using the SCUBA-2 camera on the James Clerk Maxwell Telescope. The
0.5-degree diameter circular region we surveyed contains 297 young stellar
objects with an age estimated at about 3Myr. We detect 9 of these objects, 8 of
which have infrared excesses from an inner disc. We also serendipitously detect
3 non-stellar sources at > 5sigma that are likely background submillimetre
galaxies. The 9 detected stars have inferred disc masses ranging from 5 to
about 17MJup, assuming similar dust properties as Taurus discs and an ISM
gas-to-dust ratio of 100. There is a net positive signal toward the positions
of the individually undetected infrared excess sources indicating a mean disc
mass of 0.5 MJup . Stacking the emission toward those stars without infrared
excesses constrains their mean disc mass to less than 0.3MJup, or an equivalent
Earth mass in dust. The submillimetre luminosity distribution is significantly
different from that in the younger Taurus region, indicating disc mass
evolution as star forming regions age and the infrared excess fraction
decreases. Submillimeter Array observations reveal CO emission toward 4 sources
demonstrating that some, but probably not much, molecular gas remains in these
relatively evolved discs. These observations provide new constraints on the
dust and gas mass of protoplanetary discs during the giant planet building
phase and provide a reference level for future studies of disc evolution.


title: Three-Dimensional Anderson Localization in Variable Scale Disorder

abstract:
  We report on the impact of variable-scale disorder on 3D Anderson
localization of a non-interacting ultracold atomic gas. A spin-polarized gas of
fermionic atoms is localized by allowing it to expand in an optical speckle
potential. Using a sudden quench of the localized density distribution, we
verify that the density profile is representative of the underlying
single-particle localized states. The geometric mean of the disordering
potential correlation lengths is varied by a factor of four via adjusting the
aperture of the speckle focusing lens. We observe that the root-mean-square
size of the localized gas increases approximately linearly with the speckle
correlation length, in qualitative agreement with the scaling predicted by weak
scattering theory.


title: Phase retrieval from very few measurements

abstract:
  In many applications, signals are measured according to a linear process, but
the phases of these measurements are often unreliable or not available. To
reconstruct the signal, one must perform a process known as phase retrieval.
This paper focuses on completely determining signals with as few intensity
measurements as possible, and on efficient phase retrieval algorithms from such
measurements. For the case of complex M-dimensional signals, we construct a
measurement ensemble of size 4M-4 which yields injective intensity
measurements; this is conjectured to be the smallest such ensemble. For the
case of real signals, we devise a theory of "almost" injective intensity
measurements, and we characterize such ensembles. Later, we show that phase
retrieval from M+1 almost injective intensity measurements is NP-hard,
indicating that computationally efficient phase retrieval must come at the
price of measurement redundancy.


title:
Exploring Pedagogical Content Knowledge of Physics Instructors and
  Teaching Assistants Using the Force Concept Inventory

abstract:
  The Force Concept Inventory (FCI) has been widely used to assess student
understanding of introductory mechanics concepts by a variety of educators and
physics education researchers. One reason for this extensive use is that many
of the items on the FCI have strong distractor choices that correspond to
students' alternate conceptions in mechanics. Instruction is unlikely to be
effective if instructors do not know the common alternate conceptions of
introductory physics students and explicitly take into account students'
initial knowledge state in their instructional design. Here, we discuss
research involving the FCI to evaluate the pedagogical content knowledge of
both instructors and teaching assistants (TAs) of varying teaching experience.
For each item on the FCI, the instructors and TAs were asked to identify the
most common incorrect answer choice of introductory physics students. We also
discussed the responses individually with a few instructors. Then, we used the
FCI pre-test and post-test data from a large population (~900) of introductory
physics students to assess the pedagogical content knowledge of physics
instructors and TAs. We find that while both physics instructors and TAs, on
average, performed better than random guessing at identifying introductory
students' difficulties with FCI content, they did not identify many common
difficulties that introductory physics students have, even after traditional
instruction. Moreover, the ability to correctly identify students' difficulties
was not correlated with the teaching experience of the physics instructors.


title: A hybrid approach for the implementation of the Heston model

abstract:
  We propose a hybrid tree-finite difference method in order to approximate the
Heston model. We prove the convergence by embedding the procedure in a
bivariate Markov chain and we study the convergence of European and American
option prices. We finally provide numerical experiments that give accurate
option prices in the Heston model, showing the reliability and the efficiency
of the algorithm.


title:
Exploring Pedagogical Content Knowledge of Teaching Assistants Using the
  Test of Understanding Graphs in Kinematics

abstract:
  The Test of Understanding Graphs in Kinematics (TUG-K) is a multiple choice
test developed by Beichner in 1994 to assess students' understanding of
kinematics graphs. Many of the items on the TUG-K have strong distractor
choices which correspond to students' common difficulties with kinematics
graphs. Instruction is unlikely to be effective if instructors do not know the
common difficulties of introductory physics students and explicitly take them
into account in their instructional design. We evaluate the pedagogical content
knowledge of first year physics graduate students enrolled in a teaching
assistant (TA) training course related to topics covered in the TUG-K. In
particular, for each item on the TUG-K, the graduate students were asked to
identify which incorrect answer choice they thought would be most commonly
selected by introductory physics students if they did not know the correct
answer after instruction in relevant concepts. We used the graduate student
data and the data from Beichner's original paper for introductory physics
students to assess the relevant pedagogical content knowledge (PCK) of the
graduate students. We find that, although the graduate students, on average,
performed better than random guessing at identifying introductory student
difficulties on the TUG-K, they did not identify many common difficulties that
introductory students have with graphs in kinematics even after traditional
instruction. In addition, we find that the ability of graduate students to
identify the difficulties of introductory students is context dependent.


title:
Propagation-invariant beams with quantum pendulum spectra: from Bessel
  beams to Gaussian beam-beams

abstract:
  We describe a new class of propagation-invariant light beams with Fourier
transform given by an eigenfunction of the quantum mechanical pendulum. These
beams, whose spectra (restricted to a circle) are doubly-periodic Mathieu
functions in azimuth, depend on a field strength parameter. When the parameter
is zero, pendulum beams are Bessel beams, and as the parameter approaches
infinity, they resemble transversely propagating one-dimensional Gaussian
wavepackets (Gaussian beam-beams). Pendulum beams are the eigenfunctions of an
operator which interpolates between the squared angular momentum operator and
the linear momentum operator. The analysis reveals connections with Mathieu
beams, and insight into the paraxial approximation.


title: An Antenna for Directional Detection of WISPy Dark Matter

abstract:
  It is an intriguing possibility that the cold dark matter of the Universe may
consist of very light and very weakly interacting particles such as axion(-like
particles) and hidden photons. This opens up (but also requires) new techniques
for direct detection. One possibility is to use reflecting surfaces to
facilitate the conversion of dark matter into photons, which can be
concentrated in a detector with a suitable geometry. In this note we show that
this technique also allows for directional detection and inference of the full
vectorial velocity spectrum of the dark matter particles. We also note that the
non-vanishing velocity of dark matter particles is relevant for the conception
of (non-directional) discovery experiments and outline relevant features.


title: Assembly of filamentary void galaxy configurations

abstract:
  We study the formation and evolution of filamentary configurations of dark
matter haloes in voids. Our investigation uses the high-resolution LambdaCDM
simulation CosmoGrid to look for void systems resembling the VGS_31 elongated
system of three interacting galaxies that was recently discovered by the Void
Galaxy Survey (VGS) inside a large void in the SDSS galaxy redshift survey. HI
data revealed these galaxies to be embedded in a common elongated envelope,
possibly embedded in intravoid filament. In the CosmoGrid simulation we look
for systems similar to VGS_31 in mass, size and environment. We find a total of
eight such systems. For these systems, we study the distribution of neighbour
haloes, the assembly and evolution of the main haloes and the dynamical
evolution of the haloes, as well as the evolution of the large-scale structure
in which the systems are embedded. The spatial distribution of the haloes
follows that of the dark matter environment. We find that VGS_31-like systems
have a large variation in formation time, having formed between 10 Gyr ago and
the present epoch. However, the environments in which the systems are embedded
evolved resemble each other substantially. Each of the VGS_31-like systems is
embedded in an intra-void wall, that no later than z = 0.5 became the only
prominent feature in its environment. While part of the void walls retain a
rather featureless character, we find that around half of them are marked by a
pronounced and rapidly evolving substructure. Five haloes find themselves in a
tenuous filament of a few Mpc/h long inside the intra-void wall. Finally, we
compare the results to observed data from VGS_31. Our study implies that the
VGS_31 galaxies formed in the same (proto)filament, and did not meet just
recently. The diversity amongst the simulated halo systems indicates that
VGS_31 may not be typical for groups of galaxies in voids.


title:
Green function surface-integral method for nonlocal response of
  plasmonic nanowires in arbitrary dielectric environments

abstract:
  We develop a nonlocal-response generalization to the Green-function
surface-integral method (GSIM), also known as the boundary-element method
(BEM). This numerically light method can accurately describe the linear
hydrodynamic nonlocal response of arbitrarily shaped plasmonic nanowires in
arbitrary dielectric backgrounds. All previous general-purpose methods for
nonlocal response are bulk methods. We also expand the possible geometries to
which the usual local-response GSIM can be applied, by showing how to
regularize singularities that occur in the surface integrals when the
nanoparticles touch a dielectric substrate. The same regularization works for
nonlocal response. Furthermore, an effective theory is developed to explain the
numerically observed nonlocal effects. The nonlocal frequency blueshift of a
cylindrical nanowire in an inhomogeneous background generally increases as the
nanowire radius and the longitudinal wavenumber become smaller, or when the
effective background permittivity or the mode inhomogeneity increase. The
inhomogeneity can be expressed in terms of an effective angular momentum of the
surface-plasmon mode. We compare local and nonlocal response of free-standing
nanowires, and of nanowires close to and on top of planar dielectric
substrates. Especially for the latter geometry, considerable differences in
extinction cross sections are found for local as compared to nonlocal response,
similar to what is found for plasmonic dimer structures.


title:
Linear magnetoconductivity in multiband spin-density-wave metals with
  nonideal nesting

abstract:
  In several parent iron-pnictide compounds the resistivity has an extended
range of linear magnetic field dependence. We argue that there is a simple and
natural explanation of this behavior. Spin density wave transition leads to
Fermi-surface reconstruction corresponding to strong modification of the
electronic spectrum near the nesting points. It is difficult for quasiparticles
to pass through these points during their orbital motion in magnetic field,
because they must turn sharply. As the area of the Fermi surface affected by
the nesting points increases proportionally to magnetic field, this mechanism
leads to the linear magnetoresistance. The crossover between the quadratic and
linear regimes takes place at the field scale set by the SDW gap and scattering
rate.


title:
Impact of Propagation Environment on Energy-Efficient Relay Placement:
  Model and Performance Analysis

abstract:
  The performance of a relay-based cellular network is greatly affected by the
relay location within a cell. Existing results for optimal relay placement do
not reflect how the radio propagation environment and choice of the coding
scheme can impact system performance. In this paper, we analyze the impact on
relaying performance of node distances, relay height and line-of-sight
conditions for both uplink and downlink transmissions, using several relay
coding schemes. Our first objective is to propose a geometrical model for
energy-efficient relay placement that requires only a small number of
characteristic distances. Our second objective is to estimate the maximum cell
coverage of a relay-aided cell given power constraints, and conversely, the
averaged energy consumption given a cell radius. We show that the practical
full decode-forward scheme performs close to the energy-optimized partial
decode-forward scheme when the relay is ideally located. However, away from
this optimum relay location, performance rapidly degrades and more advanced
coding scheme, such as partial decode-forward, is needed to maintain good
performance and allow more freedom in the relay placement. Finally, we define a
trade-off between cell coverage and energy efficiency, and show that there
exists a relay location for which increasing the cell coverage has a minimal
impact on the average energy consumed per unit area.


title:
Large SU(3) breaking effects and CP violation in $B^+ $ decays into
  three charged SU(3) octet pseudoscalar mesons

abstract:
  TThe LHCb collaboration has recently reported evidence for non-zero CP
asymmetries in $B^+$ decays into $\pi^+ K^+ K^-,\; \pi^+\pi^+\pi^-,\; K^+ K^+
K^- $ and $K^+\pi^+\pi^-$. The branching ratios for these decays have also been
measured with different values ranging from $5\times 10^{-6}$ to $51\times
10^{-6}$. If flavor $SU(3)$ symmetry is a good symmetry for $B$ decays, in the
case that the dominant amplitude is momentum independent it is expected that
branching ratios $Br$ and CP violating rate differences $\Delta_{CP} = \Gamma -
\overline{\Gamma}$ satisfy, $Br(\pi^+\pi^+\pi^-) = 2Br(\pi^+ K^+ K^-)$,
$Br(K^+K^+K^-) = 2 Br(K^+\pi^+\pi^-)$, and $\Delta_{CP}(\pi^+\pi^+\pi^-) =
2\Delta_{CP}(\pi^+ K^+K^-) = - \Delta_{CP}(K^+K^+K^-) =
-2\Delta_{CP}(K^+\pi^+\pi^-)$. The experimental data do not exhibit the
expected pattern for the branching ratios. The rate differences for $B^+\to
\pi^+\pi^+\pi^-$ and $B^+\to K^+ K^+ K^-$ satisfy the relation between $\Delta
S =0$ and $\Delta S=1$ well, but the other two do not, with the CP asymmetries
having different signs than expected. In this work we study how to including
momentum dependent and also $SU(3)$ breaking effects on these decays to explain
experimental data. We find that only including lowest order derivative terms,
in the $SU(3)$ limit, the decay patterns cannot be explained. Large $SU(3)$
breaking effects are needed to explain the data.


title:
Methodus inveniendi lineas curvas maximi minimive proprietate gaudentes,
  sive solutio problematis isoperimetrici lattissimo sensu accepti

abstract:
  This translation has been withdrawn due to certain imperfections and
mistakes, which are corrected in the version uploaded at The Euler Archive (see
E65 at http://www.eulerarchive.org/)


title:
Relaxation towards negative temperatures in bosonic systems: Generalized
  Gibbs ensembles and beyond integrability

abstract:
  Motivated by the recent experimental observation of negative absolute
temperature states in systems of ultracold atomic gases in optical lattices
[Braun et al., Science 339, 52 (2013)], we investigate theoretically the
formation of these states. More specifically, we consider the relaxation after
a sudden inversion of the external parabolic confining potential in the
one-dimensional inhomogeneous Bose-Hubbard model. First, we focus on the
integrable hard-core boson limit which allows us to treat large systems and
arbitrarily long times, providing convincing numerical evidence for relaxation
to a generalized Gibbs ensemble at negative temperature T<0, a notion we define
in this context. Second, going beyond one dimension, we demonstrate that the
emergence of negative temperature states can be understood in a dual way in
terms of positive temperatures, which relies on a dynamic symmetry of the
Hubbard model. We complement the study by exact diagonalization simulations at
finite values of the on-site interaction.


title:
Loop quantum cosmology of k=1 FLRW: Effects of inverse volume
  corrections

abstract:
  We consider the k=1 Friedman-Lemaitre-Robertson-Walker (FLRW) model within
loop quantum cosmology (LQC), from the perspective of the two available
quantization prescriptions. We focus our attention on the existence of the so
called `inverse corrections' in the quantization process. We derive the
corresponding quantum constraint operators, and study in detail the issue of
the self-adjointness of the quantum Hamiltonian constraint for two different
quantizations based on open holonomies. Furthermore, we analize in detail the
resulting effective theories, paying special attention to issues such as the
boundedness of different scalar observables such as energy density and
expansion. We show that the inclusion of the inverse corrections solves one of
the main undesirable features of the previous formalism, namely the
unboundedness of the energy density and expansion near the bounce on the full
(effective) phase space. We briefly comment on possible consequences of this
new feature.


title: Corrections of Order $\alpha \alpha_s$ to W Boson Decays

abstract:
  We present the calculation of the mixed two-loop QCD/electroweak corrections
to hadronic W boson decays within the Standard Model. The optical theorem is
applied to the W boson two-point function. The multi-scale integrals are
computed with the help of asymptotic expansions, which factorize the three-loop
diagrams into one- and two-loop vacuum and propagator-type integrals.


title:
Topological crystalline Kondo insulators and universal topological
  surface states of SmB$_6$

abstract:
  We prove theoretically that certain strongly correlated Kondo insulators are
topological crystalline insulators with nontrivial topology protected by
crystal symmetries. In particular, we find that SmB$_6$ is such a material. In
addition to a nontrivial Z$_2$ topological index protected by time reversal
symmetry, SmB$_6$ also has nontrival mirror Chern numbers protected by mirror
symmetries. On the $(100)$ surface of SmB$_6$, the nontrivial mirror Chern
numbers do not generate additional surface states beyond those predicted by the
Z$_2$ topological index. However, on the $(110)$ surface, two more surface
Dirac points are predicted. Remarkably, we find that for SmB$_6$ both the Z$_2$
topological index and the mirror Chern numbers are independent of microscopic
details, which enables us to obtain surface state properties that are
universal.


title:
MixedGrad: An O(1/T) Convergence Rate Algorithm for Stochastic Smooth
  Optimization

abstract:
  It is well known that the optimal convergence rate for stochastic
optimization of smooth functions is $O(1/\sqrt{T})$, which is same as
stochastic optimization of Lipschitz continuous convex functions. This is in
contrast to optimizing smooth functions using full gradients, which yields a
convergence rate of $O(1/T^2)$. In this work, we consider a new setup for
optimizing smooth functions, termed as {\bf Mixed Optimization}, which allows
to access both a stochastic oracle and a full gradient oracle. Our goal is to
significantly improve the convergence rate of stochastic optimization of smooth
functions by having an additional small number of accesses to the full gradient
oracle. We show that, with an $O(\ln T)$ calls to the full gradient oracle and
an $O(T)$ calls to the stochastic oracle, the proposed mixed optimization
algorithm is able to achieve an optimization error of $O(1/T)$.


title: Macroscopic Violation of Duality Generated on a Laser Beam

abstract:
  It is shown theoretically and experimentally that passage of a laser beam
through particular conventional Ronchi gratings prepares the beam in an altered
state that violates quantum duality. The violation is characterized by a
readily measured net transfer of energy between the prepared beam and an
unmodified beam from a similar, independent laser. Notably, the experiment is
conducted with the beams at macroscopic power levels where measurability of the
duality-violating transfer is vastly improved over that of the discrete photon
regime. These results are consistent with other recently reported experiments
that have challenged the validity of the duality-related principle of
complementarity.


title: Probing surface electric field noise with a single ion

abstract:
  We report room-temperature electric field noise measurements combined with
in-situ surface characterization and cleaning of a microfabricated ion trap. We
used a single-ion electric field noise sensor in combination with surface
cleaning and analysis tools, to investigate the relationship between electric
field noise from metal surfaces in vacuum and the composition of the surface.
These experiments were performed in a novel setup that integrates ion trapping
capabilities with surface analysis tools. We find that surface cleaning of an
aluminum-copper surface significantly reduces the level of electric field
noise, but the surface does not need to be atomically clean to show noise
levels comparable to those of the best cryogenic traps. The post-cleaning noise
levels are low enough to allow fault-tolerant trapped-ion quantum information
processing on a microfabricated surface trap.


title: The vehicle relocation problem for the one-way electric vehicle sharing

abstract:
  Traditional car-sharing services are based on the two-way scheme, where the
user picks up and returns the vehicle at the same parking station. Some
services permits also one-way trips, which allows the user to return the
vehicle in another station. The one-way scheme is quite more attractive for the
users, but may pose a problem for the distribution of the vehicles, due to a
possible unbalancing between the user demand and the availability of vehicles
or free slots at the stations. Such a problem is more complicated in the case
of electrical car sharing, where the travel range depends on the level of
charge of the vehicles. The paper presents a new approach for the Electric
Vehicle Relocation Problem, where cars are moved by personnel of the service
operator to keep the system balanced. Such a problem generates a challenging
pickup and delivery problem with new features that to the best of our knowledge
never have been considered in the literature. We yield a Mixed Integer Linear
Programming formulation and some valid inequalities to speed up its solution
through a state-of-the art solver (CPLEX). We test our approach on verisimilar
instances built on the Milan road network.


title: SiGe quantum dots for fast hole spin Rabi oscillations

abstract:
  We report on hole g-factor measurements in three terminal SiGe self-assembled
quantum dot devices with a top gate electrode positioned very close to the
nanostructure. Measurements of both the perpendicular as well as the parallel
g-factor reveal significant changes for a small modulation of the top gate
voltage. From the observed modulations we estimate that, for realistic
experimental conditions, hole spins can be electrically manipulated with Rabi
frequencies in the order of 100MHz. This work emphasises the potential of
hole-based nano-devices for efficient spin manipulation by means of the
g-tensor modulation technique.


title: Mixed Gauginos Sending Mixed Messages to the LHC

abstract:
  Supersymmetric models with a Dirac gluino have been shown to be considerably
less constrained from LHC searches than models with a Majorana gluino. In this
paper, we generalize this discussion to models with a "Mixed Gluino", that
acquires both Dirac and Majorana masses, as well as models in which electroweak
gauginos contribute to squark production. Our primary interest is the degree of
suppression of the cross section for first generation squarks compared with a
gluino with a pure Majorana mass. We find that not all Majorana masses are
alike -- a Majorana mass for the gluino can suppress the squark production
cross section, whereas a Majorana mass for the adjoint fermion partner leads to
an increased cross section, compared with a pure Dirac gluino. In the presence
of electroweak gauginos, squark production can increase by at most a factor of
a few above the pure Dirac gluino case when the electroweak gauginos have
purely Majorana masses near to the squark masses. This unusual set of gaugino
masses is interesting since the usual Higgs quartic coupling would not be
suppressed. When the electroweak gaugino masses are much lighter than the
squarks, there is a negligible change to the squark production cross section.
We explain both of these cases in detail by considering the various
subprocesses for squark production at the LHC. Continued searches for squark
production with cross sections much smaller than expected in the MSSM are
absolutely warranted, and we suggest new simplified models to fully
characterize the collider constraints.


title: Self-Learning for Player Localization in Sports Video

abstract:
  This paper introduces a novel self-learning framework that automates the
label acquisition process for improving models for detecting players in
broadcast footage of sports games. Unlike most previous self-learning
approaches for improving appearance-based object detectors from videos, we
allow an unknown, unconstrained number of target objects in a more generalized
video sequence with non-static camera views. Our self-learning approach uses a
latent SVM learning algorithm and deformable part models to represent the shape
and colour information of players, constraining their motions, and learns the
colour of the playing field by a gentle Adaboost algorithm. We combine those
image cues and discover additional labels automatically from unlabelled data.
In our experiments, our approach exploits both labelled and unlabelled data in
sparsely labelled videos of sports games, providing a mean performance
improvement of over 20% in the average precision for detecting sports players
and improved tracking, when videos contain very few labelled images.


title:
An Explanation for the Different X-ray to Optical Column Densities in
  the Environments of Gamma Ray Bursts: A Progenitor Embedded in a Dense Medium

abstract:
  We study the > 10 ratios in the X-ray to optical column densities inferred
from afterglow spectra of Gamma Ray Bursts due to gas surrounding their
progenitors. We present time-evolving photoionization calculations for these
afterglows and explore different conditions for their environment. We find that
homogenous models of the environment (constant density) predict X-ray columns
similar to those found in the optical spectra, with the bulk of the opacity
being produced by neutral material at large distances from the burst. This
result is independent of gas density or metallicity. Only models assuming a
progenitor immersed in a dense (10^(2-4) cm-3) cloud of gas (with radius ~10
pc), with a strong, declining gradient of density for the surrounding
interstellar medium are able to account for the large X-ray to optical column
density ratios. However, to avoid an unphysical correlation between the size of
this cloud, and the size of the ionization front produced by the GRB, the
models also require that the circumburst medium is already ionized prior to the
burst. The inferred cloud masses are <10^6 M_solar, even if low metallicities
in the medium are assumed (Z~0.1 Z_solar). These cloud properties are
consistent with those found in giant molecular clouds and our results support a
scenario in which the progenitors reside within intense star formation regions
of galaxies. Finally, we show that modeling over large samples of GRB
afterglows may offer strong constraints on the range of properties in these
clouds, and the host galaxy ISM.


title: Behavioral Traps and the Equilibrium Problem on Hadamard Manifolds

abstract:
  In this paper we present a sufficient condition for the existence of a
solution for an equilibrium problem on an Hadamard manifold and under suitable
assumptions on the sectional curvature, we propose a framework for the
convergence analysis of a proximal point algorithm to solve this equilibrium
problem in finite time. Finally we offer an application to personal equilibrum
problems as behavioral traps problems, using a recent "variational rationality"
approach of human behavior.


title: Chromospheric evaporation in sympathetic coronal bright points

abstract:
  {Chromospheric evaporation is a key process in solar flares that has
extensively been investigated using the spectroscopic observations. However,
direct soft X-ray (SXR) imaging of the process is rare, especially in remote
brightenings associated with the primary flares that have recently attracted
dramatic attention.} {We intend to find the evidence for chromospheric
evaporation and figure out the cause of the process in sympathetic coronal
bright points (CBPs), i.e., remote brightenings induced by the primary CBP.}
{We utilise the high-cadence and high-resolution SXR observations of CBPs from
the X-ray Telescope (XRT) aboard the Hinode spacecraft on 2009 August 23.} {We
discover thermal conduction front propagating from the primary CBP, i.e., BP1,
to one of the sympathetic CBPs, i.e., BP2 that is 60$\arcsec$ away from BP1.
The apparent velocity of the thermal conduction is $\sim$138 km s$^{-1}$.
Afterwards, hot plasma flowed upwards into the loop connecting BP1 and BP2 at a
speed of $\sim$76 km s$^{-1}$, a clear signature of chromospheric evaporation.
Similar upflow was also observed in the loop connecting BP1 and the other
sympathetic CBP, i.e., BP3 that is 80$\arcsec$ away from BP1, though less
significant than BP2. The apparent velocity of the upflow is $\sim$47 km
s$^{-1}$. The thermal conduction front propagating from BP1 to BP3 was not well
identified except for the jet-like motion also originating from BP1.} {We
propose that the gentle chromospheric evaporation in the sympathetic CBPs were
caused by thermal conduction originating from the primary CBP.}


title: Students learning center strategy based on e-learning and blogs

abstract:
  Education is the main infrastructure for promoting a nation and increasing
their competitiveness in globalization era that involves the use of information
technology (IT). This paper has goal to expand the alternative for learning
strategy based on IT for final year students that will conduct a research for
their final report. The final year students are expected have the ability to
learn independently to manage the needness of their learning supply. In this
paper, the author will discuss how to use the e-learning media and blogs to
manage the independently learning environment or self-learning. E-learning
offers the flexibilities in term of time and place in supporting the learning
activities as well as a media for faculty/lecturer to disseminate learning
materials. While the blog has been a free medium for the publication of variety
contents, including academic contents. In this paper, author suggests some the
institutions regulations, lecturers roles, and students participations are
involve in set the learning environment based on e-learning and blog. These
activities able to support students in learning independently or self-learning.


title:
Wavelet-based genetic association analysis of functional phenotypes
  arising from high-throughput sequencing assays

abstract:
  Understanding how genetic variants influence cellular-level processes is an
important step towards understanding how they influence important
organismal-level traits, or "phenotypes", including human disease
susceptibility. To this end scientists are undertaking large-scale genetic
association studies that aim to identify genetic variants associated with
molecular and cellular phenotypes, such as gene expression, transcription
factor binding, or chromatin accessibility. These studies use high-throughput
sequencing assays (e.g. RNA-seq, ChIP-seq, DNase-seq) to obtain high-resolution
data on how the traits vary along the genome in each sample. However, typical
association analyses fail to exploit these high-resolution measurements,
instead aggregating the data at coarser resolutions, such as genes, or windows
of fixed length. Here we develop and apply statistical methods that better
exploit the high-resolution data. The key idea is to treat the sequence data as
measuring an underlying "function" that varies along the genome, and then,
building on wavelet-based methods for functional data analysis, test for
association between genetic variants and the underlying function. Applying
these methods to identify genetic variants associated with chromatin
accessibility (dsQTLs) we find that they identify substantially more
associations than a simpler window-based analysis, and in total we identify 772
novel dsQTLs not identified by the original analysis.


title:
Deformation quantization with separation of variables of an endomorphism
  bundle

abstract:
  Given a holomorphic Hermitian vector bundle and a star-product with
separation of variables on a pseudo-Kaehler manifold, we construct a star
product on the sections of the endomorphism bundle of the dual bundle which
also has the appropriately generalized property of separation of variables. For
this star product we prove a generalization of Gammelgaard's graph-theoretic
formula.


title:
Finite size scaling study of $N_{\text{f}}=4$ finite density QCD on the
  lattice

abstract:
  We explore the phase space spanned by the temperature and the chemical
potential for 4-flavor lattice QCD using the Wilson-clover quark action. In
order to determine the order of the phase transition, we apply finite size
scaling analyses to gluonic and quark observables including plaquette, Polyakov
loop and quark number density, and examine their susceptibility, skewness,
kurtosis and Challa-Landau-Binder cumulant. Simulations were carried out on
lattices of a temporal size fixed at $N_{\text{t}}=4$ and spatial sizes chosen
from $6^3$ up to $10^3$. Configurations were generated using the phase
reweighting approach, while the value of the phase of the quark determinant
were carefully monitored. The $\mu$-parameter reweighting technique is employed
to precisely locate the point of the phase transition. Among various
approximation schemes for calculating the ratio of quark determinants needed
for $\mu$-reweighting, we found the Taylor expansion of the logarithm of the
quark determinant to be the most reliable. Our finite-size analyses show that
the transition is first order at $(\beta, \kappa, \mu/T)=(1.58, 0.1385,
0.584\pm 0.008)$ where $(m_\pi/m_\rho, T/m_\rho)=(0.822, 0.154)$. It weakens
considerably at $(\beta, \kappa, \mu/T)=(1.60, 0.1371, 0.821\pm 0.008)$ where
$(m_\pi/m_\rho, T/m_\rho)=(0.839, 0.150)$, and a crossover rather than a first
order phase transition cannot be ruled out.


title: Hopf Insulators and Their Topologically Protected Surface States

abstract:
  Three-dimensional (3D) topological insulators in general need to be protected
by certain kinds of symmetries other than the presumed $U(1)$ charge
conservation. A peculiar exception is the Hopf insulators which are 3D
topological insulators characterized by an integer Hopf index. To demonstrate
the existence and physical relevance of the Hopf insulators, we construct a
class of tight-binding model Hamiltonians which realize all kinds of Hopf
insulators with arbitrary integer Hopf index. These Hopf insulator phases have
topologically protected surface states and we numerically demonstrate the
robustness of these topologically protected states under general random
perturbations without any symmetry other than the $U(1)$ charge conservation
that is implicit in all kinds of topological insulators.


title:
A polarization maintaining scheme for 1.5 {\mu}m polarization entangled
  photon pair generation in optical fibers

abstract:
  In this paper, the generation of polarization entangled photon pairs at 1.5
{\mu}m is experimentally demonstrated utilizing a polarization maintaining
all-fiber loop, consisting of a piece of commercial polarization maintaining
fiber and a polarization beam splitter/combiner with polarization maintaining
fiber pigtails. A quantum state tomography measurement is performed to analyze
the entanglement characteristic of the generated quantum state. In the
experiment, a polarization entangled Bell state is generated with a
entanglement fidelity of 0.97+/-0.03 and a purity of 0.94+/-0.03 demonstrating
that the proposed scheme can realize polarization entangled photon pair
generation with polarization maintaining property which is desired in
applications of quantum communication and quantum information.


title: Clustering Chinese Regional Cultures with Online-gaming Data

abstract:
  To identify cluster of societies is not easy in subject to the availability
of data. In this study, from the prospective of computational social science,
we propose a novel method to cluster Chinese regional cultures. Using millions
of geotagged online-gaming data of Chinese internet users playing online card
and board games with regional features, 336 Chinese cities are grouped into
several main clusters. The geographic boundaries of clusters coincide with the
boundaries of provincial regions. The north regions in China have more
geographical proximity, when regional variations in south regions are more
evident.

categories: cs.CY cs.SI physics.data-an physics.soc-ph


title: CRPS M-estimation for max-stable models

abstract:
  Max-stable random fields provide canonical models for the dependence of
multivariate extremes. Inference with such models has been challenging due to
the lack of tractable likelihoods. In contrast, the finite dimensional
cumulative distribution functions (CDFs) are often readily available and
natural to work with. Motivated by this fact, in this work we develop an
M-estimation framework for max-stable models based on the continuous ranked
probability score (CRPS) of multivariate CDFs. We start by establishing
conditions for the consistency and asymptotic normality of the CRPS-based
estimators in a general context. We then implement them in the max-stable
setting and provide readily computable expressions for their asymptotic
covariance matrices. The resulting point and asymptotic confidence interval
estimates are illustrated over popular simulated models. They enjoy accurate
coverages and offer an alternative to composite likelihood based methods.


title: NOVA: QoE-driven Optimization of DASH-based Video Delivery in Networks

abstract:
  We consider the problem of optimizing video delivery for a network supporting
video clients streaming stored video. Specifically, we consider the problem of
jointly optimizing network resource allocation and video quality adaptation.
Our objective is to fairly maximize video clients' Quality of Experience (QoE)
realizing tradeoffs among the mean quality, temporal variability in quality,
and fairness, incorporating user preferences on rebuffering and cost of video
delivery. We present a simple asymptotically optimal online algorithm, NOVA, to
solve the problem. NOVA is asynchronous, and using minimal communication,
distributes the tasks of resource allocation to network controller, and quality
adaptation to respective video clients. Video quality adaptation in NOVA is
also optimal for standalone video clients, and is well suited for use with DASH
framework. Further, we extend NOVA for use with more general QoE models,
networks shared with other traffic loads and networks using fixed/legacy
resource allocation.