title:
Generalized linear sampling method for elastic-wave sensing of
  heterogeneous fractures

abstract:
  A theoretical foundation is developed for active seismic reconstruction of
fractures endowed with spatially-varying interfacial condition
(e.g.~partially-closed fractures, hydraulic fractures). The proposed indicator
functional carries a superior localization property with no significant
sensitivity to the fracture's contact condition, measurement errors, and
illumination frequency. This is accomplished through the paradigm of the
$F_\sharp$-factorization technique and the recently developed Generalized
Linear Sampling Method (GLSM) applied to elastodynamics. The direct scattering
problem is formulated in the frequency domain where the fracture surface is
illuminated by a set of incident plane waves, while monitoring the induced
scattered field in the form of (elastic) far-field patterns. The analysis of
the well-posedness of the forward problem leads to an admissibility condition
on the fracture's (linearized) contact parameters. This in turn contributes
toward establishing the applicability of the $F_\sharp$-factorization method,
and consequently aids the formulation of a convex GLSM cost functional whose
minimizer can be computed without iterations. Such minimizer is then used to
construct a robust fracture indicator function, whose performance is
illustrated through a set of numerical experiments. For completeness, the
results of the GLSM reconstruction are compared to those obtained by the
classical linear sampling method (LSM).


title: Heavy Higgs Bosons at Low $\tan \beta$: from the LHC to 100 TeV

abstract:
  We present strategies to search for heavy neutral Higgs bosons decaying to
top quark pairs, as often occurs at low $\tan \beta$ in type II two Higgs
doublet models such as the Higgs sector of the MSSM. The resonant production
channel is unsatisfactory due to interference with the SM background. We
instead propose to utilize same-sign dilepton signatures arising from the
production of heavy Higgs bosons in association with one or two top quarks and
subsequent decay to a top pair. We find that for heavier neutral Higgs bosons
the production in association with one top quark provides greater sensitivity
than production in association with two top quarks. We obtain current limits at
the LHC using Run I data at 8 TeV and forecast the sensitivity of a dedicated
analysis during Run II at 14 TeV. Then we perform a detailed BDT study for the
14 TeV LHC and a future 100 TeV collider.


title: C60 as a probe for astrophysical environments

abstract:
  The C60 molecule has been recently detected in a wide range of astrophysical
environments through its four active intramolecular vibrational modes (T1u)
near 18.9, 17.4, 8.5, and 7.0 microns. The strengths of the mid-infrared
emission bands have been used to infer astrophysical conditions in the
fullerene-rich regions. Widely varying values of the relative intrinsic
strengths (RIS) of these four bands are reported in laboratory and theoretical
papers, which impedes the derivation of the excitation mechanism of C60 in the
astrophysical sources. The spectroscopic analysis of the C60 samples produced
with our method delivers highly reproducible RIS values of 100, 25 +- 1, 26 +-
1, and 40 +- 4. A comparison of the inferred C60 emission band strengths with
the astrophysical data shows that the observed strengths cannot be explained in
terms of fluorescent or thermal emission alone. The large range in the observed
17.4/18.9 emission ratios indicates that either the emission bands contain
significant contributions from emitters other than C60, or that the population
distribution among the C60 vibrational modes is affected by physical processes
other than thermal or UV excitation, such as chemo-luminescence from nascent
C60 or possibly, Poincare fluorescence resulting from an inverse internal
energy conversion. We have carefully analyzed the effect of the weakly-active
fundamental modes and second order modes in the mid-infrared spectrum of C60
and propose that neutral C60 is the carrier of the unidentified emission band
at 6.49 microns which has been observed in fullerene-rich environments.


title:
An adaptive finite element PML method for the elastic wave scattering
  problem in periodic structures

abstract:
  An adaptive finite element method is presented for the elastic scattering of
a time-harmonic plane wave by a periodic surface. First, the unbounded physical
domain is truncated into a bounded computational domain by introducing the
perfectly matched layer (PML) technique. The well-posedness and exponential
convergence of the solution are established for the truncated PML problem by
developing an equivalent transparent boundary condition. Second, an a
posteriori error estimate is deduced for the discrete problem and is used to
determine the finite elements for refinements and to determine the PML
parameters. Numerical experiments are included to demonstrate the competitive
behavior of the proposed adaptive method.


title:
Temperature-dependent collective effects for silicene, germanene and
  monolayer black phosphorus

abstract:
  We have calculated numerically electron exchange, correlation energies and
dynamical polarization function for newly discovered silicene, germanene and
black phosphorus (BP), consisting of puckered layers of elemental phosphorus
atoms, broadening the range of two-dimensional (2D) materials at various
temperatures. As a matter of fact, monolayer BP, produced by mechanical and
liquid exfoliation techniques, has been predicted to be an insulator with a
large energy splitting 1.6 eV for the quasiparticle band structure. We compare
the dependence of these energies on the chemical potential, field-induced gap
and the temperature and concluded that in many cases they behave qualitatively
similarly, i.e., increasing with the doping, decreasing significantly at
elevated temperatures, and displaying different dependence on the asymmetry gap
at various temperatures. Furthermore, we used the dynamical polarizability to
investigate the new "split" plasmon branches in the puckered lattices and
predict a unique splitting, different from that in gapped graphene, for various
energy gaps. Our results are crucial for stimulating electronic, transport and
collective studies of these novel materials, as well as for enhancing
silicene-based fabrication and technologies for photovoltaics and transistor
devices.


title: On the Energy-Based Variational Model for Vector Magnetic Hysteresis

abstract:
  We consider the quasi-static magnetic hysteresis model based on a
dry-friction like representation of magnetization. The model has a consistent
energy interpretation, is intrinsically vectorial, and ensures a direct
calculation of the stored and dissipated energies at any moment in time, and
hence not only on the completion of a closed hysteresis loop. We discuss the
variational formulation of this model and derive an efficient numerical scheme,
avoiding the usually employed approximation which can be inaccurate in the
vectorial case. The parameters of this model for a nonoriented steel are
identified using a set of first order reversal curves. Finally, the model is
incorporated as a local constitutive relation into a 2D finite element
simulation accounting for both the magnetic hysteresis and the eddy current.


title: Visual Model Validation via Inline Replication

abstract:
  Data visualizations typically show retrospective views of an existing dataset
with little or no focus on repeatability. However, consumers of these tools
often use insights gleaned from retrospective visualizations as the basis for
decisions about future events. In this way, visualizations often serve as
visual predictive models despite the fact that they are typically designed to
present historical views of the data. This "visual predictive model" approach,
however, can lead to invalid inferences. In this paper, we describe an approach
to visual model validation called Inline Replication (IR) which, similar to the
cross-validation technique used widely in machine learning, provides a
nonparametric and broadly applicable technique for visual model assessment and
repeatability. This paper describes the overall IR process and outlines how it
can be integrated into both traditional and emerging "big data" visualization
pipelines. Examples are provided showing IR integrated within common
visualization techniques (such as bar charts and linear regression lines) as
well as a more fully-featured visualization system designed for complex
exploratory analysis tasks.


title: Status of a minimal composite Higgs theory

abstract:
  We analyze three sets of gauge ensembles in our extended physics program of a
particularly important BSM gauge theory with a fermion doublet in the two-index
symmetric (sextet) representation of the SU(3) BSM color gauge group. Our
investigations include chiral symmetry breaking $\rm{(\chi SB)}$ in the
p-regime and $\epsilon$-regime, the mass of the composite ${\rm 0^{++}}$
scalar, resonance spectroscopy, new physics from gauge anomaly constraints, and
the role of stable sextet BSM baryons with Electroweak interactions in dark
matter searches. Important new goals include studies of the ${\rm 0^{++}}$
scalar entangled with Goldstone dynamics in the p-regime and the
$\epsilon$-regime, the resonance spectrum with particular attention to emerging
LHC signals, like recent hints for diphoton excess at 750 GeV or diboson
anomalies in the 2 TeV range. All results reported here are preliminary before
journal publication including some post-conference material for the discussion.


title:
Estimating the Entanglement Negativity from low-order moments of the
  partially transposed density matrix

abstract:
  We show how to find families of infima and suprema for the entanglement
negativity using only a few, low-order moments of the partially transposed
density matrix $\rho^{T_2}.$ These moments can be measured using the multi-copy
quantum circuits previously given by the author, which define a set of
multi-copy expectation values and thus can be used with the replica trick. As
such, these bounds are suitable for use with Quantum Monte Carlo methods, and
the lower order versions of the estimates may be experimentally accessible for
some systems. Using more moments for higher-order versions of these methods
will produce tighter estimates, unless and until statistical noise causes the
measurement of the highest order moment to fail. Should this happen, the data
from lower order moments can still be used for lower-order estimates.


title: The maximum product of sizes of cross-intersecting families

abstract:
  We say that a set $A$ $t$-intersects a set $B$ if $A$ and $B$ have at least
$t$ common elements. Two families $\mathcal{A}$ and $\mathcal{B}$ of sets are
said to be cross-$t$-intersecting if each set in $\mathcal{A}$ $t$-intersects
each set in $\mathcal{B}$. A subfamily $\mathcal{S}$ of a family $\mathcal{F}$
is called a $t$-star of $\mathcal{F}$ if the sets in $\mathcal{S}$ have $t$
common elements. Let $l(\mathcal{F},t)$ denote the size of a largest $t$-star
of $\mathcal{F}$. We call $\mathcal{F}$ a $(\leq r)$-family if each set in
$\mathcal{F}$ has at most $r$ elements. We determine a function $c :
\mathbb{N}^3 \rightarrow \mathbb{N}$ such that the following holds. If
$\mathcal{A}$ is a subfamily of a $(\leq r)$-family $\mathcal{F}$ with
$l(\mathcal{F},t) \geq c(r,s,t)l(\mathcal{F},t+1)$, $\mathcal{B}$ is a
subfamily of a $(\leq s)$-family $\mathcal{G}$ with $l(\mathcal{G},t) \geq
c(r,s,t)l(\mathcal{G},t+1)$, and $\mathcal{A}$ and $\mathcal{B}$ are
cross-$t$-intersecting, then $|\mathcal{A}||\mathcal{B}| \leq
l(\mathcal{F},t)l(\mathcal{G},t)$. Some known results follow from this, and we
identify several natural classes of families for which the bound is attained.


title:
Fairly Random: The Impact of Winning the Toss on the Probability of
  Winning

abstract:
  In a competitive sport, every little thing matters. Yet, many sports leave
some large levers out of the reach of the teams, and in the hands of fate. In
cricket, world's second most popular sport by some measures, one such
lever---the toss---has been subject to much recent attention. Using a large
novel dataset of 44,224 cricket matches, we estimate the impact of winning the
toss on the probability of winning. The data suggest that winning the toss
increases the chance of winning by a small ($\sim$ 2.8\%) but significant
margin. The advantage varies heftily and systematically, by how closely matched
the competing teams are, and by playing conditions---tautologically, winning
the toss in conditions where the toss grants a greater advantage, for e.g., in
day and night matches, has a larger impact on the probability of winning.


title: Faster Eigenvector Computation via Shift-and-Invert Preconditioning

abstract:
  We give faster algorithms and improved sample complexities for estimating the
top eigenvector of a matrix $\Sigma$ -- i.e. computing a unit vector $x$ such
that $x^T \Sigma x \ge (1-\epsilon)\lambda_1(\Sigma)$:
  Offline Eigenvector Estimation: Given an explicit $A \in \mathbb{R}^{n \times
d}$ with $\Sigma = A^TA$, we show how to compute an $\epsilon$ approximate top
eigenvector in time $\tilde O([nnz(A) + \frac{d*sr(A)}{gap^2} ]* \log
1/\epsilon )$ and $\tilde O([\frac{nnz(A)^{3/4} (d*sr(A))^{1/4}}{\sqrt{gap}} ]
* \log 1/\epsilon )$. Here $nnz(A)$ is the number of nonzeros in $A$, $sr(A)$
is the stable rank, $gap$ is the relative eigengap. By separating the $gap$
dependence from the $nnz(A)$ term, our first runtime improves upon the
classical power and Lanczos methods. It also improves prior work using fast
subspace embeddings [AC09, CW13] and stochastic optimization [Sha15c], giving
significantly better dependencies on $sr(A)$ and $\epsilon$. Our second running
time improves these further when $nnz(A) \le \frac{d*sr(A)}{gap^2}$.
  Online Eigenvector Estimation: Given a distribution $D$ with covariance
matrix $\Sigma$ and a vector $x_0$ which is an $O(gap)$ approximate top
eigenvector for $\Sigma$, we show how to refine to an $\epsilon$ approximation
using $ O(\frac{var(D)}{gap*\epsilon})$ samples from $D$. Here $var(D)$ is a
natural notion of variance. Combining our algorithm with previous work to
initialize $x_0$, we obtain improved sample complexity and runtime results
under a variety of assumptions on $D$.
  We achieve our results using a general framework that we believe is of
independent interest. We give a robust analysis of the classic method of
shift-and-invert preconditioning to reduce eigenvector computation to
approximately solving a sequence of linear systems. We then apply fast
stochastic variance reduced gradient (SVRG) based system solvers to achieve our
claims.


title:
Space Charge Limited Current with Self-heating in
  Pr$_{0.7}$Ca$_{0.3}$MnO$_3$ based RRAM

abstract:
  Space Charge Limited Current (SCLC) based conduction has been identified for
PCMO-based RRAM devices based on the observation that $I \propto V^{\alpha}$
where $\alpha \approx 2$. A critical feature of the IV characteristics is a
sharp rise in current ($\alpha \gg 2$) which has been widely attributed to
trap-filled limit (TFL) followed by an apparent trap-free SCLC conduction. In
this paper, we show by TCAD analysis that trap-filled limit (TFL) is
insufficient to explain the sharp current rise ($\alpha \gg 2$). As an
alternative, we propose a shallow trap SCLC model with selfheating effect based
thermal runaway to explain the sharp current rise followed by a series
resistance dominated regime. Experimental results over a range of
25{\deg}C-125{\deg}C demonstrate all 4 regimes (i) Ohmic ($\alpha = 1$), (ii)
shallow trap SCLC ($\alpha \approx 2$), (iii) current shoot up ($\alpha \gg 2$)
and (iv) series resistance ($\alpha = 1$). Further, TCAD simulations with
thermal modeling are able to match the experimental IV characteristics in all
the regimes. Thus, a current conduction mechanism in PCMO-based RRAM supported
by detailed TCAD model is presented. Such a model is essential for further
quantitative understanding and design for PCMO-based RRAM.


title: Atomic defect states in monolayers of MoS$_2$ and WS$_2$

abstract:
  The influence of atomic vacancy defects at different concentrations on
electronic properties of MoS$_2$ and WS$_2$ monolayers is studied by means of
Slater-Koster tight-binding model with non-orthogonal $sp^3d^5$ orbitals and
including the spin-orbit coupling. The presence of vacancy defects induces
localized states in the bandgap of pristine MoS$_2$ and WS$_2$, which have
potential to modify the electronic structure of the systems, depending on the
type and concentration of the defects. It is shown that although the
contribution of metal (Mo or W) $d$ orbitals is dominant in the formation of
midgap states, the sulphur $p$ and $d$ orbitals have also considerable
contribution in the localized states, when metal defects are introduced. Our
results suggest that Mo and W defects can turn the monolayers into p-type
semiconductors, while the sulphur defects make the system a n-type
semiconductor, in agreement with ab initio results and experimental
observations.


title:
A spectre is haunting the cosmos: Quantum stability of massive gravity
  with ghosts

abstract:
  Many theories of modified gravity with higher order derivatives are usually
ignored because of serious problems that appear due to an additional ghost
degree of freedom. Most dangerously, it causes an immediate decay of the
vacuum. However, breaking Lorentz invariance can cure such abominable behavior.
By analyzing a model that describes a massive graviton together with a
remaining Boulware-Deser ghost mode we show that even ghostly theories of
modified gravity can yield models that are viable at both classical and quantum
levels and, therefore, they should not generally be ruled out. Furthermore, we
identify the most dangerous quantum scattering process that has the main impact
on the decay time and find differences to simple theories that only describe an
ordinary scalar field and a ghost. Additionally, constraints on the parameters
of the theory including some upper bounds on the Lorentz-breaking cutoff scale
are presented. In particular, for a simple theory of massive gravity we find
that a breaking of Lorentz invariance is allowed to happen even at scales above
the Planck mass. Finally, we discuss the relevance to other theories of
modified gravity.


title:
Polynomial reduction and evaluation of tree- and loop-level CHY
  amplitudes

abstract:
  We develop a polynomial reduction procedure that transforms any gauge fixed
CHY amplitude integrand for $n$ scattering particles into a $\sigma$-moduli
multivariate polynomial of what we call the $\textit{standard form}$. We show
that a standard form polynomial must have a specific $\textit{ladder type}$
monomial structure, which has finite size at any $n$, with highest multivariate
degree given by $(n-3)(n-4)/2$. This set of monomials spans a complete basis
for polynomials with rational coefficients in kinematic data on the support of
scattering equations. Subsequently, at tree and one-loop level, we employ the
global residue theorem to derive a prescription that evaluates any CHY
amplitude by means of collecting simple residues at infinity only. The
prescription is then applied explicitly to some tree and one-loop amplitude
examples.


title: Estimating Large Correlation Matrices for International Migration

abstract:
  The United Nations is the major organization producing and regularly updating
probabilistic population projections for all countries. International migration
is a critical component of such projections, and between-country correlations
are important for forecasts of regional aggregates. However, there are 200
countries and only 12 data points, each one corresponding to a five-year time
period. Thus a $200 \times 200$ correlation matrix must be estimated on the
basis of 12 data points. Using Pearson correlations produces many spurious
correlations. We propose a maximum a posteriori estimator for the correlation
matrix with an interpretable informative prior distribution. The prior serves
to regularize the correlation matrix, shrinking a priori untrustworthy elements
towards zero. Our estimated correlation structure improves projections of net
migration for regional aggregates, producing narrower projections of migration
for Africa as a whole and wider projections for Europe. A simulation study
confirms that our estimator outperforms both the Pearson correlation matrix and
a simple shrinkage estimator when estimating a sparse correlation matrix.


title: SU(2) higher-order effective quark interactions from polarization

abstract:
  Higher order quark effective interactions are found for SU(2) flavor by
departing from a non local quark-quark interaction. By integrating out a
component of the quark field, the determinant is expanded in chirally symmetric
and symmetry breaking effective interactions up to the fifh order in the quark
bilinears. The resulting coupling constants are resolved in the leading order
of the longwavelength limit and exact numerical ratios between several of these
coupling constants are obtained in the large quark mass limit. In this level,
chiral invariant interactions only show up in even powers of the quark
bilinears, i.e. ${\cal O}(\bar{\psi} \psi)^{2 n}$ ($n=1,2,3,..$), whereas
(explicit) chiral symmetry breaking terms emerge as ${\cal O}(\bar{\psi}
\psi)^{n}$ being always proportional to some power of the Lagrangian quark
mass.


title: CMB-lensing beyond the Born approximation

abstract:
  We investigate the weak lensing corrections to the cosmic microwave
background temperature anisotropies considering effects beyond the Born
approximation. To this aim, we use the small deflection angle approximation, to
connect the lensed and unlensed power spectra, via expressions for the
deflection angles up to third order in the gravitational potential. While the
small deflection angle approximation has the drawback to be reliable only for
multipoles $\ell\lesssim 2500$, it allows us to consistently take into account
the non-Gaussian nature of cosmological perturbation theory beyond the linear
level. The contribution to the lensed temperature power spectrum coming from
the non-Gaussian nature of the deflection angle at higher order is a new effect
which has not been taken into account in the literature so far. It turns out to
be the leading contribution among the post-Born lensing corrections. On the
other hand, the effect is smaller than corrections coming from non-linearities
in the matter power spectrum, and its imprint on CMB lensing is too small to be
seen in present experiments.


title: Mimetic Explicit Time Discretiztions

abstract:
  This paper is part of a program to combine a staggered time and staggered
spatial discretization of continuum mechanics problems so that any property of
the continuum that is proved using vector calculus can be proven in an
analogous way for the discretized system. We require that the discretizations
be second order accurate and have a conserved quantity that approximates the
energy for the system and guarantees stability for a reasonable constraint on
the time step. We also require that the discretization is time explicit so as
to avoid the solution of large system of possibly nonlinear algebraic
equations. The well known Yee grid discretization of Maxwell's equations is the
same as our discretization and is an early example of using a staggered space
and time grid .
  To motivate our discussion we begin by studying the staggered time or
leapfrog discretization of the harmonic oscillator and use this to introduce
the modification of the energy that is conserved. Next we use systems of linear
equations to motivate the definition of the modified energy for more complex
systems of ordinary differential equations and then apply our ideas to the
scalar wave equation in one spatial dimension. We finish by discretizing the
three dimensional scalar wave and Maxwell's equations. Because the spatial
discretization is mimetic, we obtain that the divergence of the electric and
magnetic fields are constant when there are no sources. Using the mimetic
properties the proof of this trivial and is essentially the same as in the
continuum.


title:
Smartphone Fingerprinting Via Motion Sensors: Analyzing Feasibility at
  Large-Scale and Studying Real Usage Patterns

abstract:
  Advertisers are increasingly turning to fingerprinting techniques to track
users across the web. As web browsing activity shifts to mobile platforms,
traditional browser fingerprinting techniques become less effective; however,
device fingerprinting using built-in sensors offers a new avenue for attack. We
study the feasibility of using motion sensors to perform device fingerprinting
at scale, and explore countermeasures that can be used to protect privacy.
  We perform a large-scale user study to demonstrate that motion sensor
fingerprinting is effective with even 500 users. We also develop a model to
estimate prediction accuracy for larger user populations; our model provides a
conservative estimate of at least 12% classification accuracy with 100000
users. We then investigate the use of motion sensors on the web and find,
distressingly, that many sites send motion sensor data to servers for storage
and analysis, paving the way to potential fingerprinting. Finally, we consider
the problem of developing fingerprinting countermeasures; we evaluate a
previously proposed obfuscation technique and a newly developed quantization
technique via a user study. We find that both techniques are able to
drastically reduce fingerprinting accuracy without significantly impacting the
utility of the sensors in web applications.


title: Stacking With Auxiliary Features

abstract:
  Ensembling methods are well known for improving prediction accuracy. However,
they are limited in the sense that they cannot discriminate among component
models effectively. In this paper, we propose stacking with auxiliary features
that learns to fuse relevant information from multiple systems to improve
performance. Auxiliary features enable the stacker to rely on systems that not
just agree on an output but also the provenance of the output. We demonstrate
our approach on three very different and difficult problems -- the Cold Start
Slot Filling, the Tri-lingual Entity Discovery and Linking and the ImageNet
object detection tasks. We obtain new state-of-the-art results on the first two
tasks and substantial improvements on the detection task, thus verifying the
power and generality of our approach.


title:
On the recurrence and Lyapunov time scales of the motion near the chaos
  border

abstract:
  Conditions for the emergence of a statistical relationship between $T_r$, the
chaotic transport (recurrence) time, and $T_L$, the local Lyapunov time (the
inverse of the numerically measured largest Lyapunov characteristic exponent),
are considered for the motion inside the chaotic layer around the separatrix of
a nonlinear resonance. When numerical values of the Lyapunov exponents are
measured on a time interval not greater than $T_r$, the relationship is shown
to resemble the quadratic one. This tentatively explains numerical results
presented in the literature.


title: Remixing as a Pathway to Computational Thinking

abstract:
  Theorists and advocates of "remixing" have suggested that appropriation can
act as a pathway for learning. We test this theory quantitatively using data
from more than 2.4 million multimedia programming projects shared by more than
1 million users in the Scratch online community. First, we show that users who
remix more often have larger repertoires of programming commands even after
controlling for the numbers of projects and amount of code shared. Second, we
show that exposure to computational thinking concepts through remixing is
associated with increased likelihood of using those concepts. Our results
support theories that young people learn through remixing, and have important
implications for designers of social computing systems.


title: Local law and Tracy-Widom limit for sparse random matrices

abstract:
  We consider spectral properties and the edge universality of sparse random
matrices, the class of random matrices that includes the adjacency matrices of
the Erdos-Renyi graph model $G(N,p)$. We prove a local law for the eigenvalue
density up to the spectral edges. Under a suitable condition on the sparsity,
we also prove that the rescaled extremal eigenvalues exhibit GOE Tracy-Widom
fluctuations if a deterministic shift of the spectral edge due to the sparsity
is included. For the adjacency matrix of the Erdos-Renyi graph this establishes
the Tracy-Widom fluctuations of the second largest eigenvalue for $p\gg
N^{-2/3}$ with a deterministic shift of order $(Np)^{-1}$.


title:
Improved calculation of the gravitational wave spectrum from kinks on
  infinite cosmic strings

abstract:
  Gravitational wave observations provide unique opportunities to search for
cosmic strings. One of the strongest sources of gravitational waves is
discontinuities of cosmic strings, called kinks, which are generated at points
of intersection. Kinks on infinite strings are known to generate a
gravitational wave background over a wide range of frequencies. In this paper,
we calculate the spectrum of the gravitational wave background by numerically
solving the evolution equation for the distribution function of the kink
sharpness. We find that the number of kinks for small sharpness is larger than
the analytical estimate used in a previous work, which makes a difference in
the spectral shape. Our numerical approach also helps to avoid the use of
analytic approximations, and enables us to make a more precise prediction on
the spectral amplitude for future gravitational wave experiments.


title: Observation of the 2$^+$ isomer in $^{52}$Co

abstract:
  We report the first observation of the 2$^+$ isomer in $^{52}$Co, produced in
the $\beta$ decay of the 0$^+$, $^{52}$Ni ground state. We have observed three
$\gamma$-rays at 849, 1910, and 5185 keV characterizing the $\beta$
de-excitation of the isomer. We have measured a half-life of 102(6) ms for the
isomeric state. The Fermi and Gamow-Teller transition strengths for the $\beta$
decay of $^{52m}$Co to $^{52}$Fe have been determined. We also add new
information on the $\beta$ decay of the 6$^+$, $^{52}$Co ground state, for
which we have measured a half-life of 112(3) ms.


title:
Optical-SZE Scaling Relations for DES Optically Selected Clusters within
  the SPT-SZ Survey

abstract:
  We study the Sunyaev-Zel'dovich effect (SZE) signature in South Pole
Telescope (SPT) data for an ensemble of 719 optically identified galaxy
clusters selected from 124.6 deg$^2$ of the Dark Energy Survey (DES) science
verification data, detecting a stacked SZE signal down to richness
$\lambda\sim20$. The SZE signature is measured using matched-filtered maps of
the 2500 deg$^2$ SPT-SZ survey at the positions of the DES clusters, and the
degeneracy between SZE observable and matched-filter size is broken by adopting
as priors SZE and optical mass-observable relations that are either calibrated
using SPT selected clusters or through the Arnaud et al. (2010, A10) X-ray
analysis. We measure the SPT signal to noise $\zeta$-$\lambda$, relation and
two integrated Compton-$y$ $Y_\textrm{500}$-$\lambda$ relations for the
DES-selected clusters and compare these to model expectations accounting for
the SZE-optical center offset distribution. For clusters with $\lambda > 80$,
the two SPT calibrated scaling relations are consistent with the measurements,
while for the A10-calibrated relation the measured SZE signal is smaller by a
factor of $0.61 \pm 0.12$ compared to the prediction. For clusters at $20 <
\lambda < 80$, the measured SZE signal is smaller by a factor of
$\sim$0.20-0.80 (between 2.3 and 10~$\sigma$ significance) compared to the
prediction, with the SPT calibrated scaling relations and larger $\lambda$
clusters showing generally better agreement. We quantify the required
corrections to achieve consistency, showing that there is a richness dependent
bias that can be explained by some combination of contamination of the
observables and biases in the estimated masses. We discuss possible physical
effects, as contamination from line-of-sight projections or from point sources,
larger offsets in the SZE-optical centering or larger scatter in the
$\lambda$-mass relation at lower richnesses.


title: Enhancing the Performance and Robustness of the FEAST Eigensolver

abstract:
  The FEAST algorithm is a subspace iteration method that uses a spectral
projector as a rational filter in order to efficiently solve interior
eigenvalue problems in parallel. Although the solutions from the FEAST
algorithm converge rapidly in many cases, convergence can be slow in situations
where the eigenvalues of a matrix are densely populated near the edges of the
search interval of interest, which can be detrimental to parallel load
balancing. This work introduces two methods that allow one to improve the
convergence robustness of the FEAST algorithm in these situations without
having to increase the amount of computation. Selected numerical examples are
presented and discussed


title: Multi-step production of a diphoton resonance

abstract:
  Among the questions that would be raised by the observation of a new
resonance at the LHC, particularly pressing are those concerning the production
mechanism: What is the initial state? Is the resonance produced independently
or in association with other particles? Here we present two weakly-coupled
renormalizable models for production of a diphoton resonance that differ in
both their initial and final states. In one model, a scalar particle produced
through gluon fusion decays into a diphoton particle and a light, long-lived
pseudoscalar. In another model, a $Z'$ boson produced from the annihilation of
a strange-antistrange quark pair undergoes a cascade decay that leads to a
diphoton particle and two sterile neutrinos. Various kinematic distributions
may differentiate these models from the canonical model where a diphoton
particle is directly produced in gluon fusion.


title: Radio AGN in the local universe: unification, triggering and evolution

abstract:
  Associated with one of the most important forms of active galactic nucleus
(AGN) feedback, and showing a strong preference for giant elliptical host
galaxies, radio AGN (L_1.4GHz > 10^24 W Hz^-1) are a key sub-class of the
overall AGN population. Here I review our current state of understanding of the
population of radio AGN at low and intermediate redshifts (z < 0.7),
concentrating on their AGN and host galaxy properties, and covering three
interlocking themes: the classification of radio AGN and its interpretation;
the triggering and fuelling of the jet and AGN activity; and the evolution of
the host galaxies. I show that much of the observed diversity in the AGN
properties of radio AGN can be explained in terms of a combination of
orientation/anisotropy, mass accretion rate, and variability effects. The
detailed morphologies of the host galaxies are consistent with the triggering
of strong-line radio galaxies (SLRG) in galaxy mergers. However, the star
formation properties and cool ISM contents suggest that the triggering mergers
are relatively minor in terms of their gas masses in most cases, and would not
lead to major growth of the supermassive black holes and stellar bulges;
therefore, apart from a minority (<20%) that show evidence for higher star
formation rates and more massive cool ISM reservoirs, the SLRG represent
late-time re-triggering of activity in mature giant elliptical galaxies. In
contrast, the host and environmental properties of weak-line radio galaxies
(WLRG) with Fanaroff-Riley class I (FRI) radio morphologies are consistent with
more gradual fuelling of the activity via gas accretion at low rates onto the
supermassive black holes.


title: Global constraints on heavy neutrino mixing

abstract:
  We derive general constraints on the mixing of heavy Seesaw neutrinos with
the SM fields from a global fit to present flavour and electroweak precision
data. We explore and compare both a completely general scenario, where the
heavy neutrinos are integrated out without any further assumption, and the more
constrained case were only 3 additional heavy states are considered. The latter
assumption implies non-trivial correlations in order to reproduce the correct
neutrino masses and mixings as observed by oscillation data and thus some
qualitative differences can be found with the more general scenario. The
relevant processes analyzed in the global fit include searches for Lepton
Flavour Violating (LFV) decays, probes of the universality of weak
interactions, CKM unitarity bounds and electroweak precision data. In
particular, a comparative and detailed study of the present and future
sensitivity of the different LFV experiments is performed. We find a mild
$1-2\sigma$ preference for non-zero heavy neutrino mixing of order 0.03-0.04 in
the electron and tau sectors. At the $2\sigma$ level we derive bounds on all
mixings ranging from 0.1 to 0.01 with the notable exception of the $e-\mu$
sector with a more stringent bound of 0.005 from the $\mu \to e \gamma$
process.


title:
Molecular Dissociation in Presence of a Catalyst II: The bond breaking
  role of the transition from virtual to localized states

abstract:
  We address a molecular dissociation mechanism that is known to occur when a H
2 molecule approaches a catalyst with its molecular axis parallel to the
surface. It is found that molecular dissociation is a form of quantum dynamical
phase transition associated to an ana- lytic discontinuity of quite unusual
nature: the molecule is destabilized by the transition from non-physical
virtual states into actual local- ized states. Current description complements
our recent results for a molecule approaching the catalyst with its molecular
axis perpendicu- lar to the surface. Also, such a description can be seen as a
further successful implementation of a non-Hermitian Hamiltonian in a well
defined model.


title:
Reaction Rates and Kinetic Isotope Effects of H$_2$ + OH $\rightarrow$
  H$_2$O + H

abstract:
  We calculated reaction rate constants including atom tunneling of the
reaction of dihydrogen with the hydroxy radical down to a temperature of 50 K.
Instanton theory and canonical variational theory with microcanonical optimized
multidimensional tunneling (CVT/$\mu$OMT) were applied using a fitted potential
energy surface [J. Chem. Phys. 138, 154301 (2013)]. All possible
protium/deuterium isotopologues were considered. Atom tunneling increases at
about 250 K (200 K for deuterium transfer). Even at 50 K the rate constants of
all isotopologues remain in the interval $ 4 \cdot 10^{-20}$ to $4 \cdot
10^{-17}$ cm$^3$ s$^{-1}$ , demonstrating that even deuterated versions of the
title reaction are possibly relevant to astrochemical processes in molecular
clouds. The transferred hydrogen atom dominates the kinetic isotope effect at
all temperatures.


title:
Superconducting Magnet with a Minimal Steel Yoke for the Future Circular
  Collider Detector

abstract:
  The conceptual design study of a Future Circular hadron-hadron Collider
(FCC-hh) with a center-of-mass energy of the order of 100 TeV, assumed to be
constructed in a new tunnel of 80-100 km circumference, includes the
determination of the basic requirements for its detectors. A superconducting
solenoid magnet of 12-m-diameter inner bore with the central magnetic flux
density of 6 T, in combination with two superconducting dipole magnets and two
conventional toroid magnets is proposed for an FCC-hh experimental setup. The
coil of 23.468 m length has seven 3.35-m-long modules included into one
cryostat. The steel yoke with a mass of 22.6 kt consists of two barrel layers
of 0.5 m radial thickness and a 0.7-m-thick nose disk and four 0.6-m-thick
end-cap disks each side. The outer diameter of the yoke is 17.7 m. The full
length of the magnetic system is 62.6 m. The air gaps between the end-cap disks
provide for the installation of the muon chambers up to an absolute
pseudorapidity about 2.7. The superconducting dipole magnets provide
measurement of charged particle momenta in the absolute pseudorapidity region
greater than 3. The conventional forward muon spectrometer allows muon
identification in the absolute pseudorapidity region from 2.7 to 5. The magnet
is modeled with the program TOSCA from Cobham CTS Limited. The total current in
the superconducting solenoid coil is 123 MA-turns; the stored energy is 41.8
GJ. The axial force acting on each end-cap is 450 MN. The stray field is 13.7
mT at a radius of 50 m from the coil axis, and 5.2 mT at a radius of 100 m.
Many other parameters are presented and discussed.


title:
Flux Loop Measurements of the Magnetic Flux Density in the CMS Magnet
  Yoke

abstract:
  The Compact Muon Solenoid (CMS) is a general purpose detector, designed to
run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its
distinctive features include a 4 T superconducting solenoid with 6-m-diameter
by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of
construction steel. The return yoke consists of five dodecagonal three-layered
barrel wheels and four end-cap disks at each end comprised of steel blocks up
to 620 mm thick, which serve as the absorber plates of the muon detection
system. To measure the field in and around the steel, a system of 22 flux loops
and 82 3-D Hall sensors is installed on the return yoke blocks. A TOSCA 3-D
model of the CMS magnet is developed to describe the magnetic field everywhere
outside the tracking volume measured with the field-mapping machine. The first
attempt is made to measure the magnetic flux density in the steel blocks of the
CMS magnet yoke using the standard magnet discharge with the current ramp down
speed of 1.5 A/s.


title: Extremely high Q-factor toroidal metamaterials

abstract:
  We demonstrate that, owing to the unique topology of the toroidal dipolar
mode, its electric/magnetic field can be spatially confined within
subwavelength, externally accessible regions of the metamolecules, which makes
the toroidal planar metamaterials a viable platform for high Q-factor
resonators due to interfering toroidal and other dipolar modes in
metamolecules.


title: Probing axions with the neutrino signal from the next galactic supernova

abstract:
  We study the impact of axion emission in simulations of massive star
explosions, as an additional source of energy loss complementary to the
standard neutrino emission. The inclusion of this channel shortens the cooling
time of the nascent protoneutron star and hence the duration of the neutrino
signal. We treat the axion-matter coupling strength as a free parameter to
study its impact on the protoneutron star evolution as well as on the neutrino
signal. We furthermore analyze the observability of the enhanced cooling in
current and next-generation underground neutrino detectors, showing that values
of the axion mass $m_a \gtrsim 8 \times 10^{-3}$ eV can be probed. Therefore a
galactic supernova neutrino observation would provide a valuable possibility to
probe axion masses in a range within reach of the planned helioscope
experiment, the International Axion Observatory (IAXO).


title:
Multi-PeV Signals from a New Astrophysical Neutrino Flux Beyond the
  Glashow Resonance

abstract:
  The IceCube neutrino discovery was punctuated by three showers with $E_\nu$ ~
1-2 PeV. Interest is intense in possible fluxes at higher energies, though a
marked deficit of $E_\nu$ ~ 6 PeV Glashow resonance events implies a spectrum
that is soft and/or cutoff below ~few PeV. However, IceCube recently reported a
through-going track event depositing 2.6 $\pm$ 0.3 PeV. A muon depositing so
much energy can imply $E_{\nu_\mu} \gtrsim$ 10 PeV. We show that extending the
soft $E_\nu^{-2.6}$ spectral fit from TeV-PeV data is unlikely to yield such an
event. Alternatively, a tau can deposit this much energy, though requiring
$E_{\nu_\tau}$ ~10x higher. We find that either scenario hints at a new flux,
with the hierarchy of $\nu_\mu$ and $\nu_\tau$ energies suggesting a window
into astrophysical neutrinos at $E_\nu$ ~ 100 PeV if a tau. We address
implications, including for ultrahigh-energy cosmic-ray and neutrino origins.

categories: astro-ph.HE astro-ph.CO astro-ph.GA hep-ex hep-ph


title:
The production and escape of Lyman-Continuum radiation from star-forming
  galaxies at z~2 and their redshift evolution

abstract:
  We study the production rate of ionizing photons of a sample of 588 H$\alpha$
emitters (HAEs) and 160 Lyman-$\alpha$ emitters (LAEs) at $z=2.2$ in the COSMOS
field in order to assess the implied emissivity from galaxies, based on their
UV luminosity. By exploring the rest-frame Lyman Continuum (LyC) with
GALEX/$NUV$ data, we find f$_{\rm esc} < 2.8\, (6.4)$% through median (mean)
stacking. By combining the H$\alpha$ luminosity density with IGM emissivity
measurements from absorption studies, we find a globally averaged
$\langle$f$_{\rm esc}\rangle$ of $5.9^{+14.5}_{-4.2}$ % at $z=2.2$ if we assume
HAEs are the only source of ionizing photons. We find similarly low values of
the global $\langle$f$_{\rm esc}\rangle$ at $z\approx3-5$, also ruling out a
high $\langle$f$_{\rm esc}\rangle$ at $z<5$. These low escape fractions allow
us to measure $\xi_{ion}$, the number of produced ionizing photons per unit UV
luminosity, and investigate how this depends on galaxy properties. We find a
typical $\xi_{ion} \approx 10^{24.77\pm0.04}$ Hz erg$^{-1}$ for HAEs and
$\xi_{ion} \approx 10^{25.14\pm0.09}$ Hz erg$^{-1}$ for LAEs. LAEs and low mass
HAEs at $z=2.2$ show similar values of $\xi_{ion}$ as typically assumed in the
reionization era, while the typical HAE is three times less ionizing. Due to an
increasing $\xi_{ion}$ with increasing EW(H$\alpha$), $\xi_{ion}$ likely
increases with redshift. This evolution alone is fully in line with the
observed evolution of $\xi_{ion}$ between $z\approx2-5$, indicating a typical
value of $\xi_{ion} \approx 10^{25.4}$ Hz erg$^{-1}$ in the reionization era.


title: When and where did GW150914 form?

abstract:
  The recent LIGO detection of gravitational waves (GW150914), likely
originating from the merger of two $\sim 30 M_\odot$ black holes suggests
progenitor stars of low metallicity ($[Z/Z_\odot] \lesssim 0.3$), constraining
when and where the progenitor of GW150914 may have formed. We combine estimates
of galaxy properties (metallicity, star formation rate and merger rate) across
cosmic time to predict the low redshift black hole - black hole merger rate as
a function of present day host galaxy mass, $M_\mathrm{gal}$, and the formation
redshift of the progenitor system $z_\mathrm{form}$ for different progenitor
metallicities $Z_\mathrm{c}$. At $Z_\mathrm{c}=0.1 Z_\odot$, the signal is
dominated by binaries in massive galaxies with $z_\mathrm{form}\simeq 2$, with
a small contribution from binaries formed around $z_\mathrm{form}\simeq 0.5$ in
dwarf galaxies. For $Z_\mathrm{c}=0.01Z_\odot$, fast mergers are possible and
very recent star formation in dwarfs likely dominates. Additional gravitational
wave detections from merging massive black holes will provide constraints on
the mass-metallicity relation and massive star formation at high redshifts.


title:
Precise strong lensing mass profile of the CLASH galaxy cluster MACS
  2129

abstract:
  We present a detailed strong lensing (SL) mass reconstruction of the core of
the galaxy cluster MACSJ 2129.4-0741 ($\rm z_{cl}=0.589$) obtained by combining
high-resolution HST photometry from the CLASH survey with new spectroscopic
observations from the CLASH-VLT survey. A background bright red passive galaxy
at $\rm z_{sp}=1.36$, sextuply lensed in the cluster core, has four radial
lensed images located over the three central cluster members. Further 19
background lensed galaxies are spectroscopically confirmed by our VLT survey,
including 3 additional multiple systems. A total of 31 multiple images are used
in the lensing analysis. This allows us to trace with high precision the total
mass profile of the cluster in its very inner region ($\rm R<100$ kpc). Our
final lensing mass model reproduces the multiple images systems identified in
the cluster core with high accuracy of $0.4"$. This translates to an high
precision mass reconstruction of MACS 2129, which is constrained at level of
2%. The cluster has Einstein parameter $\Theta_E=(29\pm4)"$, and a projected
total mass of $\rm M_{tot}(<\Theta_E)=(1.35\pm0.03)\times 10^{14}M_{\odot}$
within such radius. Together with the cluster mass profile, we provide here
also the complete spectroscopic dataset for the cluster members and lensed
images measured with VLT/VIMOS within the CLASH-VLT survey.


title:
Examining Tatooine: Atmospheric Models of Neptune-Like Circumbinary
  Planets

abstract:
  Circumbinary planets experience a time varying irradiation pattern as they
orbit their two host stars. In this work, we present the first detailed study
of the atmospheric effects of this irradiation pattern on known and
hypothetical gaseous circumbinary planets. Using both a one-dimensional Energy
Balance Model and a three-dimensional General Circulation Model, we look at the
temperature differences between circumbinary planets and their equivalent
single-star cases in order to determine the nature of the atmospheres of these
planets. We find that for circumbinary planets on stable orbits around their
host stars, temperature differences are on average no more than 1.0% in the
most extreme cases. Based on detailed modeling with the General Circulation
Model, we find that these temperature differences are not large enough to
excite circulation differences between the two cases. We conclude that gaseous
circumbinary planets can be treated as their equivalent single-star case in
future atmospheric modeling efforts.


title: Ideal MHD(-Einstein) Solutions Obeying The Force-Free Condition

abstract:
  We find two families of analytic solutions to the ideal magnetohydrodynamics
(iMHD) equations, in a class of 4-dimensional (4D) curved spacetimes. The
plasma current is null, and as a result, the stress-energy tensor of the plasma
itself can be chosen to take a cosmological-constant-like form. Despite the
presence of a plasma, the force-free condition - where the electromagnetic
current is orthogonal to the Maxwell tensor - continues to be maintained.
Moreover, a special case of one of these two families leads us to a fully
self-consistent solution to the Einstein-iMHD equations: we obtain the
Vaidya-(anti-)de Sitter metric sourced by the plasma and a null electromagnetic
stress tensor. We also provide a Mathematica code that researchers may use to
readily verify analytic solutions to these iMHD equations in any curved 4D
geometry.


title:
Entanglement entropy of composite Fermi liquid states on the lattice: In
  support of the Widom formula

abstract:
  Quantum phases characterized by surfaces of gapless excitations are known to
violate the otherwise ubiquitous boundary law of entanglement entropy in the
form of a multiplicative log correction: $S\sim L^{d-1} \log L$. Using
variational Monte Carlo, we calculate the second R\'enyi entropy for a model
wavefunction of the $\nu=1/2$ composite Fermi liquid (CFL) state defined on the
two-dimensional triangular lattice. By carefully studying the scaling of the
total R\'enyi entropy and, crucially, its contributions from the modulus and
sign of the wavefunction on various finite-size geometries, we argue that the
prefactor of the leading $L \log L$ term is equivalent to that in the analogous
free fermion wavefunction. In contrast to the recent results of Shao et al.
[PRL 114, 206402 (2015)], we thus conclude that the "Widom formula" holds even
in this non-Fermi liquid CFL state. More generally, our results further
elucidate---and place on a more quantitative footing---the relationship between
nontrivial wavefunction sign structure and $S\sim L \log L$ entanglement
scaling in such highly entangled gapless phases.


title: Dark Matter Overview: Collider, Direct and Indirect Detection Searches

abstract:
  The complementarity of direct, indirect and collider searches for dark matter
has improved our understanding concerning the properties of the dark matter
particle. I will review the basic concepts that these methods rely upon and
highlight what are the most important information they provide when it comes
down to interpret the results in terms of Weakly Interacting Massive Particles
(WIMPs). Later, I go over some of the latest results emphasizing the
implications to dark matter theory in a broad sense and point out recent
developments and prospects in the field.


title:
The Star-formation History and Accretion-Disk Fraction Among the K-Type
  Members of the Scorpius-Centaurus OB Association

abstract:
  We present results of a spectroscopic survey for new K- and M-type members of
Scorpius-Centaurus (Sco-Cen), the nearest OB Association (~100-200 pc). Using
an X-ray, proper motion and color-magnitude selected sample, we obtained
spectra for 361 stars, for which we report spectral classifications and Li and
Halpha equivalent widths. We identified 156 new members of Sco-Cen, and
recovered 51 previously published members. We have combined these with
previously known members to form a sample of 493 solar-mass (~0.7-1.3 Msun)
members of Sco-Cen. We investigated the star-formation history of this sample,
and re-assessed the ages of the massive main-sequence turn-off and the G-type
members in all three subgroups. We performed a census for circumstellar disks
in our sample using WISE infrared data and find a protoplanetary disk fraction
for K-type stars of 4.4$^{+1.6}_{-0.9}$% for Upper Centaurus-Lupus and Lower
Centaurus-Crux at ~16 Myr and 9.0$^{+4.0}_{-2.2}$% for Upper Scorpius at ~10
Myr. These data are consistent with a protoplanetary disk e-folding timescale
of ~4-5 Myr for ~1 Msun stars, twice that previously quoted (Mamajek 2009), but
consistent with the Bell et al. revised age scale of young clusters. Finally,
we construct an age map of Scorpius-Centaurus which clearly reveals
substructure consisting of concentrations of younger and older stars. We find
evidence for strong age gradients within all three subgroups. None of the
subgroups are consistent with being simple, coeval populations which formed in
single bursts, but likely represents a multitude of smaller star formation
episodes of hundreds to tens of stars each.


title:
A simple characterization of homogeneous Young measures and weak $L^1$
  convergence of their densities

abstract:
  We formulate a simple characterization of homogeneous Young measures
associated with measurable functions. It is based on the notion of the
quasi-Young measure introduced in the previous article published in this
Journal. First, homogeneous Young measures associated with the measurable
functions are recognized as the constant mappings defined on the domain of the
underlying function with values in the space of probability measures on the
range of these functions. Then the characterization of homogeneous Young
measures via image measures is formulated. Finally, we investigate the
connections between weak convergence of the homogeneous Young measures
understood as elements of the Banach space of scalar valued measures and the
weak* L1 sequential convergence of their densities. A scalar case of the smooth
functions and their Young measures being Lebesgue-Stieltjes measures is also
analyzed.


title: Finding all monomials in a polynomial ideal

abstract:
  Given a $d \times n$ integer matrix $A$, the main result is an elementary,
simple-to-state algorithm that finds the largest $A$-graded ideal contained in
any ideal $I$ in a polynomial ring $\Bbbk[x_1,\ldots,x_n]$. The special case
where $A$ is an identity matrix yields that $(t.I) \cap \Bbbk[x_1,\ldots,x_n]$
is the largest monomial ideal in $I$, where the generators of $t.I$ are those
of $I$ but with each variable $x_i$ replaced by $t_i x_i$ for an invertible
variable $t_i$.


title: Bridging the Capacity Gap Between Interactive and One-Way Communication

abstract:
  We study the communication rate of coding schemes for interactive
communication that transform any two-party interactive protocol into a protocol
that is robust to noise.
  Recently, Haeupler (FOCS '14) showed that if an $\epsilon > 0$ fraction of
transmissions are corrupted, adversarially or randomly, then it is possible to
achieve a communication rate of $1 - \widetilde{O}(\sqrt{\epsilon})$.
Furthermore, Haeupler conjectured that this rate is optimal for general input
protocols. This stands in contrast to the classical setting of one-way
communication in which error-correcting codes are known to achieve an optimal
communication rate of $1 - \Theta(H(\epsilon)) = 1 -
\widetilde{\Theta}(\epsilon)$.
  In this work, we show that the quadratically smaller rate loss of the one-way
setting can also be achieved in interactive coding schemes for a very natural
class of input protocols. We introduce the notion of average message length, or
the average number of bits a party sends before receiving a reply, as a natural
parameter for measuring the level of interactivity in a protocol. Moreover, we
show that any protocol with average message length $\ell =
\Omega(\mathrm{poly}(1/\epsilon))$ can be simulated by a protocol with optimal
communication rate $1 - \Theta(H(\epsilon))$ over an oblivious adversarial
channel with error fraction $\epsilon$. Furthermore, under the additional
assumption of access to public shared randomness, the optimal communication
rate is achieved ratelessly, i.e., the communication rate adapts automatically
to the actual error rate $\epsilon$ without having to specify it in advance.
  This shows that the capacity gap between one-way and interactive
communication can be bridged even for very small (constant in $\epsilon$)
average message lengths, which are likely to be found in many applications.


title: Effect of size on necking of dynamically loaded notched bars

abstract:
  The influence of material inertia on neck development in a notched round bar
is analyzed numerically. Dynamic axisymmetric calculations are carried out for
isotropically hardening elastic-viscoplastic solids so that both material
strain rate sensitivity and material inertia are accounted for. The focus is on
the effect of bar size on whether the notch triggers necking or necking
initiates away from the notch. The governing equations are presented in
non-dimensional form and two key non-dimensional groups that involve both
material and loading parameters are identified. For both non-dimensional
groups, with all parameters fixed except for bar size, it is found that for
sufficiently small bars, the notch triggers necking, whereas for sufficiently
large bars necking ultimately occurs away from the notch. With material
properties fixed, for one non-dimensional group the transition to necking away
from the notch corresponds to increasing imposed velocity whereas for the other
non- dimensional group this transition takes place for decreasing imposed
strain rate. Both these transitions correspond to increasing bar size. The
results indicate that this transition is governed by material inertia but the
bar size at which it occurs depends on the material properties, particularly
strain hardening and strain rate hardening.


title: Full metastable asymptotic of the Fisher information

abstract:
  We establish an expansion by Gamma-convergence of the Fisher information
relative to the reference measure exp(-beta V), where V is a generic multiwell
potential and beta goes to infinity. The expansion reveals a hierarchy of
multiple scales reflecting the metastable behavior of the underlying overdamped
Langevin dynamics: distinct scales emerge and become relevant depending on
whether one considers probability measures concentrated on local minima of V,
probability measures concentrated on critical points of V, or generic
probability measures on R^d. We thus fully describe the asymptotic behavior of
minima of the Fisher information over regular sets of probabilities. The
analysis mostly relies on spectral properties of diffusion operators and the
related semiclassical Witten Laplacian and covers also the case of a compact
smooth manifold as underlying space.


title: Greedy Column Subset Selection: New Bounds and Distributed Algorithms

abstract:
  The problem of column subset selection has recently attracted a large body of
research, with feature selection serving as one obvious and important
application. Among the techniques that have been applied to solve this problem,
the greedy algorithm has been shown to be quite effective in practice. However,
theoretical guarantees on its performance have not been explored thoroughly,
especially in a distributed setting. In this paper, we study the greedy
algorithm for the column subset selection problem from a theoretical and
empirical perspective and show its effectiveness in a distributed setting. In
particular, we provide an improved approximation guarantee for the greedy
algorithm which we show is tight up to a constant factor, and present the first
distributed implementation with provable approximation factors. We use the idea
of randomized composable core-sets, developed recently in the context of
submodular maximization. Finally, we validate the effectiveness of this
distributed algorithm via an empirical study.


title:
Leibniz algebras constructed by representations of General Diamond Lie
  algebras

abstract:
  In this paper we construct a minimal faithful representation of the
$(2m+2)$-dimensional complex general Diamond Lie algebra,
$\mathfrak{D}_m(\mathbb{C})$, which is isomorphic to a subalgebra of the
special linear Lie algebra $\mathfrak{sl}(m+2,\mathbb{C})$. We also construct a
faithful representation of the general Diamond Lie algebra $\mathfrak{D}_m$
which is isomorphic to a subalgebra of the special symplectic Lie algebra
$\mathfrak{sp}(2m+2,\mathbb{R})$. Furthermore, we describe Leibniz algebras
with corresponding $(2m+2)$-dimensional general Diamond Lie algebra
$\mathfrak{D}_m$ and ideal generated by the squares of elements giving rise to
a faithful representation of $\mathfrak{D}_m$.


title: Data-driven software security: Models and methods

abstract:
  For computer software, our security models, policies, mechanisms, and means
of assurance were primarily conceived and developed before the end of the
1970's. However, since that time, software has changed radically: it is
thousands of times larger, comprises countless libraries, layers, and services,
and is used for more purposes, in far more complex ways. It is worthwhile to
revisit our core computer security concepts. For example, it is unclear whether
the Principle of Least Privilege can help dictate security policy, when
software is too complex for either its developers or its users to explain its
intended behavior.
  This paper outlines a data-driven model for software security that takes an
empirical, data-driven approach to modern software, and determines its exact,
concrete behavior via comprehensive, online monitoring. Specifically, this
paper briefly describes methods for efficient, detailed software monitoring, as
well as methods for learning detailed software statistics while providing
differential privacy for its users, and, finally, how machine learning methods
can help discover users' expectations for intended software behavior, and
thereby help set security policy. Those methods can be adopted in practice,
even at very large scales, and demonstrate that data-driven software security
models can provide real-world benefits.


title:
Asymptotic Analysis of Objectives based on Fisher Information in Active
  Learning

abstract:
  Obtaining labels can be costly and time-consuming. Active learning allows a
learning algorithm to intelligently query samples to be labeled for efficient
learning. Fisher information ratio (FIR) has been used as an objective for
selecting queries in active learning. However, little is known about the theory
behind the use of FIR for active learning. There is a gap between the
underlying theory and the motivation of its usage in practice. In this paper,
we attempt to fill this gap and provide a rigorous framework for analyzing
existing FIR-based active learning methods. In particular, we show that FIR can
be asymptotically viewed as an upper bound of the expected variance of the
log-likelihood ratio. Additionally, our analysis suggests a unifying framework
that not only enables us to make theoretical comparisons among the existing
querying methods based on FIR, but also allows us to give insight into the
development of new active learning approaches based on this objective.


title:
Estimation of Interpretable eQTL Effect Sizes Using a Log of Linear
  Model

abstract:
  The study of expression Quantitative Trait Loci (eQTL) is an important
problem in genomics and biomedicine. While detection (testing) of eQTL
associations has been widely studied, less work has been devoted to the
estimation of eQTL effect size. To reduce false positives, detection methods
frequently rely on linear modeling of rank-based normalized or log-transformed
gene expression data. Unfortunately, these approaches do not correspond to the
simplest model of eQTL action, and thus yield estimates of eQTL association
that can be uninterpretable and inaccurate. In this paper we propose a new,
log-of-linear model for eQTL action, termed ACME, that captures allelic
contributions to cis-acting eQTLs in an additive fashion, yielding effect size
estimates that correspond to a biologically coherent model of cis-eQTLs. We
describe a non-linear least-squares algorithm to fit the model by maximum
likelihood, and obtain corresponding $p$-values. We perform careful
investigation of the model using a combination of simulated data and data from
the Genotype Tissue Expression (GTEx) project. Our results reveal little
evidence for dominance effects, a parsimonious result that accords with a
simple biological model for allele-specific expression and supports use of the
ACME model. We show that Type-I error is well-controlled under our approach in
a realistic setting, so that rank-based normalizations are unnecessary.
Furthermore, we show that such normalizations can be detrimental to power and
estimation accuracy under the proposed model. We then provide summaries of ACME
effect sizes for whole-genome cis-eQTLs in the GTEx data.


title:
Dispersion for the wave equation inside strictly convex domains II: the
  general case

abstract:
  We consider the wave equation on a strictly convex domain of dimension at
least two with smooth non empty boundary and with Dirichlet boundary
conditions. We construct a sharp local in time parametrix and then proceed to
obtain dispersion estimates: our fixed time decay rate for the Green function
exhibits a $t^{1/4}$ loss with respect to the boundary less case. Moreover, we
precisely describe where and when these losses occur and relate them to
swallowtail type singularities in the wave front set, proving that the
resulting decay is optimal. Moreover, we derive better than expected Strichartz
estimates, balancing lossy long time estimates at a given incidence with short
time ones with no loss: in three dimensions, it heuristically means that, on
average the decay loss is only $t^{1/6}$.


title: Classical and quantum resonances for hyperbolic surfaces

abstract:
  For compact and for convex co-compact oriented hyperbolic surfaces, we prove
an explicit correspondence between classical Ruelle resonant states and quantum
resonant states, except at negative integers where the correspondence involves
holomorphic sections of line bundles.


title: IGR J18293-1213 is an eclipsing Cataclysmic Variable

abstract:
  Studying the population of faint hard X-ray sources along the plane of the
Galaxy is challenging because of high-extinction and crowding, which make the
identification of individual sources more difficult. IGR J18293-1213 is part of
the population of persistent sources which have been discovered by the INTEGRAL
satellite. We report on NuSTAR and Swift/XRT observations of this source,
performed on 2015 September 11. We detected three eclipsing intervals in the
NuSTAR light curve, allowing us to constrain the duration of these eclipses,
$\Delta t = 30.8^{+6.3}_{-0.0}$ min, and the orbital period of the system, $T =
6.92\pm0.01$ hr. Even though we only report an upper limit on the amplitude of
a putative spin modulation, the orbital period and the hard thermal
Bremsstrahlung spectrum of IGR J18293-1213 provide strong evidence that this
source is a magnetic Cataclysmic Variable (CV). Our NuSTAR and Swift/XRT joint
spectral analysis places strong constraints on the white dwarf mass $M_{\rm wd}
= 0.78^{+0.10}_{-0.09}$ M$_\odot$. Assuming that the mass to radius ratio of
the companion star $M_* / R_* = 1$ (solar units) and using $T$, $\Delta t$ and
$M_{\rm wd}$, we derived the mass of the companion star $M_* = 0.82\pm0.01$
M$_\odot$, the orbital separation of the binary system $a=2.14\pm0.04$
R$_\odot$, and its orbital inclination compared to the line of sight
$i=(72.2^{+2.4}_{-0.0})\pm1.0^\circ$.


title: Density estimation using Real NVP

abstract:
  Unsupervised learning of probabilistic models is a central yet challenging
problem in machine learning. Specifically, designing models with tractable
learning, sampling, inference and evaluation is crucial in solving this task.
We extend the space of such models using real-valued non-volume preserving
(real NVP) transformations, a set of powerful invertible and learnable
transformations, resulting in an unsupervised learning algorithm with exact
log-likelihood computation, exact sampling, exact inference of latent
variables, and an interpretable latent space. We demonstrate its ability to
model natural images on four datasets through sampling, log-likelihood
evaluation and latent variable manipulations.


title: Martingale Property in Terms of Semimartingale Problems

abstract:
  Starting from the seventies mathematicians face the question whether a
non-negative local martingale is a true or a strict local martingale. In this
article we answer this question from a semimartingale perspective. We connect
the martingale property to existence, uniqueness and topological properties of
semimartingale problems. This not only leads to valuable characterizations of
the martingale property, but also reveals new existence and uniqueness results
for semimartingale problems. As a case study we derive explicit conditions for
the martingale property of stochastic exponentials driven by
infinite-dimensional Brownian motion.


title: Fingerprintability of WebRTC

abstract:
  We examine WebRTC's suitability as a means of Internet censorship
circumvention. WebRTC is a framework and suite of protocols for peer-to-peer
communication between web browsers. We analyze the implementation differences
in instantiations of WebRTC that make it possible to "fingerprint"
implementations--potentially distinguishing circumvention-related uses from
ordinary ones. This question is relevant to Snowflake, an upcoming
circumvention system that uses WebRTC to turn web browsers into temporary
peer-to-peer proxies. We conduct a manual analysis of WebRTC-using applications
in order to map the space of distinguishing implementation features. We run a
fingerprinting script on a day's worth of network traffic in order to quantify
WebRTC's prevalence and diversity. Throughout, we find pitfalls that indicate
that resisting fingerprinting in WebRTC is likely to be non-trivial.


title: On the Capacity Region of ALOHA Protocol for the Internet of Things

abstract:
  Accommodating the needs of a large number of diverse users in the Internet of
Things (IoT), notably managing how the users access the common channel, has
posed unique challenges to the network designers. In this paper, we study a
heterogeneous IoT network consisting of multiple classes of users who may have
different service requirements. For this network, we consider the application
of irregular repetition slotted ALOHA (IRSA) that is shown to offer large
throughput for single-class networks. Then, we focus on finding the network
performance boundaries by studying the set of feasible throughput values for
each class, called the capacity region. To this end, we first introduce the
concept of dual network of a multi-class network meaning a homogeneous network
with the same number of users. We then prove that finding the capacity region
of the assumed multi-class network boils down to finding the maximum achievable
throughput of its dual network. Using this finding, we then discuss how any
given point of the capacity region can be achieved. Further, a delay
performance study is conducted to evaluate the average and maximum packet
transmission delay experienced by the users of each class.


title:
Nonperturbative renormalization of the Delta-S=1 weak Hamiltonian
  including the G_1 operator

abstract:
  Under renormalization, physical operators can mix with operators which vanish
by the equations of motion. Such operators cannot contribute to matrix elements
between physical states, but they contribute to operator mixing in
renormalization schemes which are defined at an off-shell momentum point, such
as the popular regularization-invariant schemes. For the first time, we
renormalize the lattice $\Delta S=1$ effective weak Hamiltonian taking into
account the most important such operator, $G_1 \propto \overline s \gamma_\nu
(1-\gamma_5) D_\mu G_{\mu\nu} d$. This removes an important systematic error in
calculations of weak matrix elements on the lattice.


title: Censors' Delay in Blocking Circumvention Proxies

abstract:
  Censors of the Internet must continually discover and block new circumvention
proxy servers. We seek to understand this process; specifically, the length of
the delay between when a proxy first becomes discoverable and when it is
actually blocked. We measure this delay in the case of obfuscated Tor bridges,
by testing their reachability before and after their introduction into Tor
Browser. We test from sites in the U.S., China, and Iran, over a period of five
months. China's national firewall blocked new bridges after a varying delay of
between 2 and 36 days. Blocking occurred only after end-user software releases,
despite bridges being potentially discoverable earlier through other channels.
While the firewall eventually discovered the bridges of Tor Browser, those that
appeared only in Orbot, a version of Tor for mobile devices, remained
unblocked. Our findings highlight the fact that censors can behave in ways that
defy intuition, presenting difficulties for threat modeling but also
opportunities for evasion.


title: Protoplanetary disks in the hostile environment of Carina

abstract:
  We report the first direct imaging of protoplanetary disks in the
star-forming region of Carina, the most distant, massive cluster in which disks
have been imaged. Using the Atacama Large Millimeter/sub-millimeter Array
(ALMA), disks are observed around two young stellar objects (YSOs) that are
embedded inside evaporating gaseous globules and exhibit jet activity. The
disks have an average size of 120 AU and total masses of 30 and 50 M_Jup. Given
the measured masses, the minimum timescale required for planet formation (~1-2
Myr) and the average age of the Carina population (~1-4 Myr), it is plausible
that young planets are present or their formation is currently ongoing in these
disks. The non-detection of millimeter emission above the 4sigma threshold (~7
M_Jup) in the core of the massive cluster Trumpler~14, an area containing
previously identified proplyd candidates, suggest evidence for rapid
photo-evaporative disk destruction in the cluster's harsh radiation field. This
would prevent the formation of giant gas planets in disks located in the cores
of Carina's dense sub-clusters, whereas the majority of YSO disks in the wider
Carina region remain unaffected by external photo-evaporation.


title:
No Thermal Inversion and a Solar Water Abundance for the Hot Jupiter
  HD209458b from HST WFC3 Emission Spectroscopy

abstract:
  The nature of the vertical thermal structure of hot Jupiter atmospheres is
one of the key questions raised by the characterization of transiting
exoplanets over the last decade. There have been claims that many hot Jupiter's
exhibit vertical profiles with increasing temperature with decreasing pressure
in the infrared photosphere that leads to the reversal of molecular absorption
bands into emission features (an inversion). However, these claims have been
based on broadband photometry rather than the unambiguous identification of
emission features with spectroscopy, and the chemical species that could cause
the thermal inversions by absorbing stellar irradiation at high altitudes have
not been identified despite extensive theoretical and observational effort.
Here we present high precision HST WFC3 observations of the dayside emission
spectrum of the hot Jupiter HD209458b; the first exoplanet suggested to have a
thermal inversion. Our observations resolve a water band in absorption at 6.2
sigma confidence. When combined with Spitzer photometry the data are indicative
of a monotonically decreasing temperature with pressure over the range 1-0.001
bar at 7.7 sigma confidence. We test the robustness of our results by exploring
a variety of model assumptions including the temperature profile
parameterization, presence of a cloud, and choice of Spitzer data reduction. We
also introduce a new analysis method, "chemical retrieval-on-retrieval", to
determine the elemental abundances from the spectrally retrieved mixing ratios
with thermochemical self-consistency and find plausible abundances consistent
with solar metallicity (0.06 - 10 x solar) and carbon-to-oxygen ratios less
than unity. This work suggests that high-precision spectrophotometric results
are required to robustly infer thermal structures and compositions of
extra-solar planet atmospheres.


title: Universal Graphs at $\aleph_{\omega_1+1}$ and Set-theoretic Geology

abstract:
  This thesis consists of two parts: the construction of a jointly universal
family of graphs, and then an exploration of set-theoretic geology.
  Firstly we shall construct a model in which
$2^{\aleph_{\omega_1}}=2^{\aleph_{\omega_1+1}}=\aleph_{\omega_1+3}$ but there
is a jointly universal family of size $\aleph_{\omega_1+2}$ of graphs on
$\aleph_{\omega_1+1}$. We take a supercompact cardinal $\kappa$ and will use
Radin forcing with interleaved collapses to change $\kappa$ into
$\aleph_{\omega_1}$. Prior to the Radin forcing we perform a preparatory
iteration to add functions from $\kappa^+$ into Radin names for what will
become members of the jointly universal family on $\kappa^+$. The same
technique can be used with any uncountable cardinal in place of $\omega_1$.
  Secondly we explore various topics in set-theoretic geology. We begin by
showing that a class Easton support iteration of $\mathrm{Add}(\kappa,1)$ at
$\kappa$ regular results in a universe that is its own generic mantle. We then
consider set forcings $\mathbb{P}$, $\mathbb{Q}$, $\mathbb{R}$ and $\mathbb{S}$
with respective generics $G$, $H$, $I$ and $J$ such that $V[G][I]=V[H][J]$ and
show that $V[G]$ and $V[H]$ must have a shared ground via
$(|\mathbb{R}|+|\mathbb{S}|)^+$-cc forcing. This allows a similar analysis of
the related situation when $\mathbb{P}$ is replaced by a class iteration and
$V[H]$ by a generic ground of $V[G]$. We conclude with a simple
characterisation of the mantle of a class forcing extension, and an
investigation of the possibilities for a version of the intermediate model
theorem that applies to class forcing.


title: Stochastic Search with Poisson and Deterministic Resetting

abstract:
  We investigate a stochastic search process in one, two, and three dimensions
in which $N$ diffusing searchers that all start at $x_0$ seek a target at the
origin. Each of the searchers is also reset to its starting point, either with
rate $r$, or deterministically, with a reset time $T$. In one dimension and for
a small number of searchers, the search time and the search cost are minimized
at a non-zero optimal reset rate (or time), while for sufficiently large $N$,
resetting always hinders the search. In general, a single searcher leads to the
minimum search cost in one, two, and three dimensions. When the resetting is
deterministic, several unexpected feature arise for $N$ searchers, including
the search time being independent of $T$ for $1/T\to 0$ and the search cost
being independent of $N$ over a suitable range of $N$. Moreover, deterministic
resetting typically leads to a lower search cost than in stochastic resetting.


title:
Convergence and quasi-optimality of adaptive finite element methods for
  harmonic forms

abstract:
  Numerical computation of harmonic forms (typically called harmonic fields in
three space dimensions) arises in various areas, including computer graphics
and computational electromagnetics. The finite element exterior calculus
framework also relies extensively on accurate computation of harmonic forms. In
this work we study the convergence properties of adaptive finite element
methods (AFEM) for computing harmonic forms. We show that a properly defined
AFEM is contractive and achieves optimal convergence rate beginning from any
initial conforming mesh. This result is contrasted with related AFEM
convergence results for elliptic eigenvalue problems, where the initial mesh
must be sufficiently fine in order for AFEM to achieve any provable convergence
rate.


title: Quantum teleportation across a metropolitan fibre network

abstract:
  If a photon interacts with a member of an entangled photon pair via a
so-called Bell-state measurement (BSM), its state is teleported over
principally arbitrary distances onto the second member of the pair. Starting in
1997, this puzzling prediction of quantum mechanics has been demonstrated many
times; however, with one very recent exception, only the photon that received
the teleported state, if any, travelled far while the photons partaking in the
BSM were always measured closely to where they were created. Here, using the
Calgary fibre network, we report quantum teleportation from a
telecommunication-wavelength photon, interacting with another telecommunication
photon after both have travelled over several kilometres in bee-line, onto a
photon at 795~nm wavelength. This improves the distance over which
teleportation takes place from 818~m to 6.2~km. Our demonstration establishes
an important requirement for quantum repeater-based communications and
constitutes a milestone on the path to a global quantum Internet.


title: Dense Urban Channel Measurements for Utility Pole Fixed Wireless Links

abstract:
  This radio channel measurement campaign characterizes the propagation
conditions experienced in a dense urban environment over fixed backhaul links
between wireless devices that are mounted on utility or traffic light poles.
The measurements characterize the 2x1 multiple input single output channel in
the 2.45 GHz band for both spatially separated omni antennas and cross
polarized directional antennas. Results presented include both small and large
scale channel statistics, antenna correlation coefficient values and the
off-broadside rejection achieved with the directional antennas.


title: Virtual correlations in single qutrit

abstract:
  We construct the positive invertible map of the mixed states of a single
qutrit onto the states of two identical fermions. It is shown that using this
one-to-one correspondence between qutrit states and states of two identical
three-dimensional fermions (the unphysical odd dimension is picked for
simplicity) one may attribute hidden entanglement to a single mixed state of
qutrit.


title:
Believing in BERT: Using expressive communication to enhance trust and
  counteract operational error in physical Human-Robot Interaction

abstract:
  Strategies are necessary to mitigate the impact of unexpected behavior in
collaborative robotics, and research to develop solutions is lacking. Our aim
here was to explore the benefits of an affective interaction, as opposed to a
more efficient, less error prone but non-communicative one. The experiment took
the form of an omelet-making task, with a wide range of participants
interacting directly with BERT2, a humanoid robot assistant. Having significant
implications for design, results suggest that efficiency is not the most
important aspect of performance for users; a personable, expressive robot was
found to be preferable over a more efficient one, despite a considerable trade
off in time taken to perform the task. Our findings also suggest that a robot
exhibiting human-like characteristics may make users reluctant to 'hurt its
feelings'; they may even lie in order to avoid this.


title:
Quantifying resonant and near-resonant interactions in rotating
  turbulence

abstract:
  Nonlinear triadic interactions are at the heart of our understanding of
turbulence. In flows where waves are present modes must not only be in a triad
to interact, but their frequencies must also satisfy an extra condition: the
interactions that dominate the energy transfer are expected to be resonant. We
derive equations that allow direct measurement of the actual degree of
resonance of each triad in a turbulent flow. We then apply the method to the
case of rotating turbulence, where eddies coexist with inertial waves. We show
that for a range of wave numbers, resonant and near-resonant triads are
dominant, the latter allowing a transfer of net energy towards two-dimensional
modes that would be inaccessible otherwise. The results are in good agreement
with approximations often done in theories of rotating turbulence, and with the
mechanism of parametric instability proposed to explain the development of
anisotropy in such flows. We also observe that, at least for the moderate
Rossby numbers studied here, marginally near-resonant and non-resonant triads
play a non-negligible role in the coupling of modes.


title: Colored Eulerian Polynomials and the Colored Permutohedron

abstract:
  This paper introduces a colored generalization of the Eulerian polynomials,
denoted the $\alpha$-colored Eulerian polynomials. We first compute these
polynomials by taking the $h$-vector of the $\alpha$-colored permutohedron, a
colored analog of the permutohedron which we develop. We also arrive at the
$\alpha$-colored Eulerian polynomials combinatorially by defining a new notion
of descent for colored permutations.


title:
Commutative character sheaves and geometric types for supercuspidal
  representations

abstract:
  We show that some types for supercuspidal representations of tamely ramified
$p$-adic groups that appear in Jiu-Kang Yu's work are geometrizable. To do so,
we define a function-sheaf dictionary for one-dimensional characters of
arbitrary smooth group schemes over finite fields. In previous work we
considered the case of commutative smooth group schemes and found that the
standard definition of character sheaves produced a dictionary with a
nontrivial kernel. In this paper we give a modification of the category of
character sheaves that remedies this defect, and is also extensible to
non-commutative groups. We then use these commutative character sheaves to
geometrize the linear characters that appear in the types introduced by
Jiu-Kang Yu, assuming that the character vanishes on a certain derived
subgroup. To define geometric types, we combine commutative character sheaves
with Gurevich and Hadani's geometrization of the Weil representation and
Lusztig's character sheaves.


title:
Experimental rectification of entropy production by a Maxwell's Demon in
  a quantum system

abstract:
  Maxwell's demon explores the role of information in physical processes.
Employing information about microscopic degrees of freedom, this "intelligent
observer" is capable of compensating entropy production (or extracting work),
apparently challenging the second law of thermodynamics. In a modern
standpoint, it is regarded as a feedback control mechanism and the limits of
thermodynamics are recast incorporating information-to-energy conversion. We
derive a trade-off relation between information-theoretic quantities empowering
the design of an efficient Maxwell's demon in a quantum system. The demon is
experimentally implemented as a spin-1/2 quantum memory that acquires
information, and employs it to control the dynamics of another spin-1/2 system,
through a natural interaction. Noise and imperfections in this protocol are
investigated by the assessment of its effectiveness. This realization provides
experimental evidence that the irreversibility on a non-equilibrium dynamics
can be mitigated by assessing microscopic information and applying a
feed-forward strategy at the quantum scale.


title: Two-Dimensionally Confined Topological Edge States in Photonic Crystals

abstract:
  We present an all-dielectric photonic crystal structure that supports
two-dimensionally confined helical topological edge states. The topological
properties of the system are controlled by the crystal parameters. An interface
between two regions of differing band topologies gives rise to topological edge
states confined in a dielectric slab that propagate around sharp corners
without backscattering. Three dimensional finite-difference time-domain
calculations show these edges to be confined in the out-of-plane direction by
total internal reflection. Such nanoscale photonic crystal architectures could
enable strong interactions between photonic edge states and quantum emitters.


title: Symmetric Tensor Nuclear Norms

abstract:
  This paper studies nuclear norms of symmetric tensors. As recently shown by
Friedland and Lim, the nuclear norm of a symmetric tensor can be achieved at a
symmetric decomposition. We discuss how to compute symmetric tensor nuclear
norms, depending on the tensor order and the ground field. Lasserre relaxations
are proposed for the computation. The theoretical properties of the relaxations
are studied. For symmetric tensors, we can compute their nuclear norms, as well
as the nuclear decompositions. The proposed methods can be extended to
nonsymmetric tensors.


title:
Integrative Methods for Post-Selection Inference Under Convex
  Constraints

abstract:
  Inference after model selection has been an active research topic in the past
few years, with numerous works offering different approaches to addressing the
perils of the reuse of data. In particular, major progress has been made
recently on large and useful classes of problems by harnessing general theory
of hypothesis testing in exponential families, but these methods have their
limitations. Perhaps most immediate is the gap between theory and practice:
implementing the exact theoretical prescription in realistic situations---for
example, when new data arrives and inference needs to be adjusted
accordingly---may be a prohibitive task. In this paper we propose a Bayesian
framework for carrying out inference after model selection in the linear model.
Our framework is very flexible in the sense that it naturally accommodates
different models for the data, instead of requiring a case-by-case treatment.
At the core of our methods is a new approximation to the exact likelihood
conditional on selection, the latter being generally intractable. We prove
that, under appropriate conditions, our approximation is asymptotically
consistent with the exact truncated likelihood. The advantages of our methods
in practical data analysis are demonstrated in simulations and in application
to HIV drug-resistance data.


title: Clock statistics for 1d Schr\"odinger operators

abstract:
  We study the 1d Schr\"odinger operators with alloy type random supercritical
decaying potential and prove the clock convergence for the local statistics of
eigenvalues. We also consider, besides the standard i.i.d. case, more general
ones with exponentially decaying correlations.


title:
Dynamics of a two-level system under strong driving: quantum gate
  optimization based on floquet theory

abstract:
  We consider the dynamics of a two-level system (qubit) driven by strong and
short resonant pulses in the framework of Floquet theory. First we derive
analytical expressions for the quasienergies and Floquet states of the driven
system. If the pulse amplitude varies very slowly, the system adiabatically
follows the instantaneous Floquet states, which acquire dynamical phases that
depend on the evolution of the quasienergies over time. The difference between
the phases acquired by the two Floquet states corresponds to a qubit state
rotation, generalizing the notion of Rabi oscillations to the case of large
driving amplitudes. If the pulse amplitude changes very fast, the evolution is
non-adiabatic, with transitions taking place between the Floquet states. We
quantify and analyze the nonadiabatic transitions during the pulse by employing
adiabatic perturbation theory and exact numerical simulations. We find that,
for certain combinations of pulse rise and fall times and maximum driving
amplitude, a destructive interference effect leads to a remarkably strong
suppression of transitions between the Floquet states. This effect provides the
basis of a quantum control protocol, which we name Floquet Interference
Efficient Suppression of Transitions in the Adiabatic basis (FIESTA), that can
be used to design ultra-fast high-fidelity single-qubit quantum gates.


title:
Multidimensional Stochastic Process Model and its Applications to
  Analysis of Longitudinal Data with Genetic Information

abstract:
  Stochastic Process Model has many applications in analysis of longitudinal
biodemographic data. Such data contain various physiological variables
(sometimes known as covariates). It also can potentially contain genetic
information available for all or a part of participants. Taking advantage from
both genetic and non-genetic information can provide future insights into a
broad range of processes describing aging-related changes in the organism. In
this paper, we implemented a multi-dimensional Genetic Stochastic Process Model
(GenSPM) in newly developed software tool, R-package stpm, which allows
researchers performing such kind of analysis.


title: The Discovery of Raman Scattering in HII Regions

abstract:
  We report here on the discovery of faint extended wings of H\alpha\ observed
out to an apparent velocity of ~ 7600 km/s in the Orion Nebula (M42) and in
five HII regions in the Large and the Small Magellanic Clouds. We show that,
these wings are caused by Raman scattering of both the O I and Si II resonance
lines and stellar continuum UV photons with H I followed by radiative decay to
the H I n=2 level. The broad wings also seen in H\beta\ and in H\gamma\ result
from Raman scattering of the UV continuum in the H I n=4 and n=5 levels
respectively.The Raman scattering fluorescence is correlated with the intensity
of the narrow permitted lines of O I and Si II. In the case of Si II, this is
explained by radiative pumping of the same 1023.7\AA\ resonance line involved
in the Raman scattering by the Ly\beta\ radiation field. The subsequent
radiative cascade produces enhanced Si II 5978.9, 6347.1$ and 6371.4\AA\
permitted transitions. Finally we show that in O I, radiative pumping of the
1025.76\AA\ resonance line by the Lyman series radiation field is also the
cause of the enhancement in the permitted lines of this species lying near
H\alpha\ in wavelength, but here the process is a little more complex. We argue
that all these processes are active in the zone of the HII region near the
ionisation front


title:
Experimental Observation of the Quantum Anomalous Hall Effect in a
  Magnetic Topological Insulator

abstract:
  The quantized version of the anomalous Hall effect has been predicted to
occur in magnetic topological insulators, but the experimental realization has
been challenging. Here, we report the observation of the quantum anomalous Hall
(QAH) effect in thin films of Cr-doped (Bi,Sb)2Te3, a magnetic topological
insulator. At zero magnetic field, the gate-tuned anomalous Hall resistance
reaches the predicted quantized value of h/e^2,accompanied by a considerable
drop of the longitudinal resistance. Under a strong magnetic field, the
longitudinal resistance vanishes whereas the Hall resistance remains at the
quantized value. The realization of the QAH effect may lead to the development
of low-power-consumption electronics.


title: Mahler equations and rationality

abstract:
  We give another proof of a result of Adamczewski and Bell concerning Mahler
equations: A formal power series satisfying a $p-$ and a $q-$Mahler equation
over ${\mathbb C}(x)$ with multiplicatively independent positive integers $p$
and $q$ is a rational function. The proof presented here is self-contained and
is essentially a compilation of proofs contained in the recent preprint
"Consistent systems of linear differential and difference equations",
arXiv:1605.02616 [math.CA], by the same authors.


title: Weighted Residuals for Very Deep Networks

abstract:
  Deep residual networks have recently shown appealing performance on many
challenging computer vision tasks. However, the original residual structure
still has some defects making it difficult to converge on very deep networks.
In this paper, we introduce a weighted residual network to address the
incompatibility between \texttt{ReLU} and element-wise addition and the deep
network initialization problem. The weighted residual network is able to learn
to combine residuals from different layers effectively and efficiently. The
proposed models enjoy a consistent improvement over accuracy and convergence
with increasing depths from 100+ layers to 1000+ layers. Besides, the weighted
residual networks have little more computation and GPU memory burden than the
original residual networks. The networks are optimized by projected stochastic
gradient descent. Experiments on CIFAR-10 have shown that our algorithm has a
\emph{faster convergence speed} than the original residual networks and reaches
a \emph{high accuracy} at 95.3\% with a 1192-layer model.