title:
Measurement of the charged pion mass using a low-density target of light
  atoms

abstract:
  We present a new evaluation of the negatively charged pion mass based on the
simultaneous spec-troscopy of pionic nitrogen and muonic oxygen transitions
using a gaseous target composed by a N 2 /O 2 mixture at 1.4 bar. We present
the experimental setup and the methods for deriving the pion mass value from
the spatial separation from the 5g -- 4 f $\pi$N transition line and the 5g --
4 f $\mu$O transition line used as reference. Moreover, we discuss the
importance to use dilute targets in order to minimize the influence of
additional spectral lines from the presence of remaining electrons during the
radiative emission. The occurrence of possible satellite lines is investigated
via hypothesis testing methods using the Bayes factor.


title: Computations of Keller maps over fields with $\tfrac16$

abstract:
  We classify Keller maps $x + H$ in dimension $n$ over fields with $\tfrac16$,
for which $H$ is homogeneous, and
  (1) deg $H = 3$ and rk $JH \le 2$;
  (2) deg $H = 3$ and $n \le 4$;
  (3) deg $H = 4$ and $n \le 3$;
  (4) deg $H = 4 = n$ and $H_1, H_2, H_3, H_4$ are linearly dependent over $K$.
  In our proof of these classifications, we formulate (and prove) several
results which are more general than needed for these classifications. One of
these results is the classification of all homogeneous polynomial maps $H$ as
in (1) over fields with $\tfrac16$.


title:
Influence of phonons on solid-state cavity-QED investigated using
  nonequilibrium Green's functions

abstract:
  The influence of electron--phonon interactions on the dynamics of a quantum
dot coupled to a photonic cavity mode is investigated using a nonequilibrium
Green's function approach. Within a polaron frame, the self-consistent-Born
approximation is used to treat the phonon-assisted scattering processes between
the quantum dot polaron and the cavity. Two-time correlators of the quantum
dot-cavity system are calculated by solving the Kadanoff-Baym equations, giving
access to photon spectra and photon indistinguishability. The non-Markovian
nature of the interaction with the phonon bath is shown to be very accurately
described by our method in various regime of cavity-quantum electrodynamics
(cavity-QED). The indistinguishability of the emitted photons emitted at zero
temperature are found to be in very good agreement with a previously reported
exact diagonalization approach [Phys.~Rev.~B~87,~081308~(2013)]. Besides, our
method enables the calculations of photon indistinguishability at finite
temperatures and for strong electron-phonon interactions. More generally, our
method opens new avenues in the study of open quantum system dynamics coupled
to non-Markovian environments.


title:
M\'etodos Matem\'aticos Aplicados \`a Mec\^anica dos Fluidos
  (Mathematical Methods Applied to Fluid Mechanics)

abstract:
  These notes are based on some lectures that the author gave at the University
of Campinas - UNICAMP. The notes are in Portuguese, and deal with some methods
of mathematics applied to Fluid Mechanics.


title:
Making Public Safety Data Accessible in the Westside Atlanta Data
  Dashboard

abstract:
  Individual neighborhoods within large cities can benefit from independent
analysis of public data in the context of ongoing efforts to improve the
community. Yet existing tools for public data analysis and visualization are
often mismatched to community needs, for reasons including geographic
granularity that does not correspond to community boundaries, siloed data sets,
inaccurate assumptions about data literacy, and limited user input in design
and implementation phases. In Atlanta this need is being addressed through a
Data Dashboard developed under the auspices of the Westside Communities
Alliance (WCA), a partnership between Georgia Tech and community stakeholders.
In this paper we present an interactive analytic and visualization tool for
public safety data within the WCA Data Dashboard. We describe a human-centered
approach to understand the needs of users and to build accessible mapping tools
for visualization and analysis. The tools include a variety of overlays that
allow users to spatially correlate features of the built environment, such as
vacant properties with criminal activity as well as crime prevention efforts.
We are in the final stages of developing the first version of the tool, with
plans for a public release in fall of 2016.


title: Possible Internal Structures and Compositions of Proxima Centauri b

abstract:
  We explore the possible Proxima Centauri b's interiors assuming the planet
belongs to the class of dense solid planets (rocky with possible addition of
water) and derive the corresponding radii. To do so, we use an internal
structure model that computes the radius of the planet along with the locations
of the different layers of materials, assuming that its mass and bulk
composition are known. Lacking detailed elementary abundances of the host star
to constrain the planet's composition, we base our model on solar system
values. We restrained the simulations to the case of solid planets without
massive atmospheres. With these assumptions, the possible radius of Proxima
Centauri b spans the 0.94--1.40 $R_\oplus$ range. The minimum value is obtained
considering a 1.10 $M_\oplus$ Mercury-like planet with a 65% core mass
fraction, whereas the highest radius is reached for 1.46 $M_\oplus$ with 50%
water in mass, constituting an ocean planet. Although this range of radii still
allows very different planet compositions, it helps characterizing many aspects
of Proxima Centauri b, such as the formation conditions of the system or the
current amount of water on the planet. This work can also help ruling out
future measurements of the planet's radius that would be physically
incompatible with a solid planetary body.


title:
Harnessing the Potential of the American Community Survey: Delving into
  Methods of Data Delivery

abstract:
  The American Community Survey (ACS) is the bedrock underpinning any analysis
of the US population, urban areas included. The Census Bureau delivers the ACS
data in multiple formats, yet in each the raw data is difficult to export in
bulk and difficult to sift through. We argue that Enigma's approach to the data
delivery, such as our raw data and metadata presentation, reflects the survey's
logical structure. It can be explored, interlinked, and searched; making it
easier to retrieve the appropriate data applicable to a question at hand. We
make the use of data more liquid via curated tables and API access; even
metadata and notes from technical documentation are programmatically
accessible. Additionally, we are working towards opening our scalable and
reproducible ingestion process of ACS estimations. This paper details all of
the ways the Census Bureau currently makes the data available, the barriers
each of these raise to applying this data in analysis and how our approach
overcomes them. Finally, this paper will address other recent innovations in
making Census datasets more usable, the use cases suited to each and how they
fit into the wider application of data science.


title:
Influence of the ferroelectric quantum critical point on SrTiO$_3$
  interfaces

abstract:
  We study a model SrTiO$_3$ interface in which conduction $t_{2g}$ electrons
couple to the ferroelectric (FE) phonon mode. We treat the FE mode within a
self-consistent phonon theory that captures its quantum critical behavior, and
show that proximity to the quantum critical point leads to universal tails in
the electron density of the form $n(z) \sim (\lambda+z)^{-2}$, where $\lambda
\sim T^{2-d/\mathfrak{z}}$, with $d=3$ the dimensionality and $\mathfrak{z}=1$
the dynamical critical exponent. Implications for the metal-insulator
transition at low electron density are discussed.


title: Algebraic and algorithmic aspects of radical parametrizations

abstract:
  In this article algebraic constructions are introduced in order to study the
variety defined by a radical parametrization (a tuple of functions involving
complex numbers, $n$ variables, the four field operations and radical
extractions). We provide algorithms to implicitize radical parametrizations and
to check whether a radical parametrization can be reparametrized into a
rational parametrization.


title:
Detecting Cognitive Appraisals from Facial Expressions for Interest
  Recognition

abstract:
  Interest makes one hold her attention on the object of interest. Automatic
recognition of interest has numerous applications in human-computer
interaction. In this paper, we study the facial expressions associated with
interest and its underlying and closely related components, namely, curiosity,
coping potential, novelty and complexity. To this end, we conducted an
experiment in which participants watched images and micro-videos while a
front-facing camera recorded their expressions. After watching each item they
self-reported their level of interest, curiosity, coping potential and
perceived novelty and complexity. Using an automated method, we tracked facial
action units (AU) and studied the relationship between the presence of facial
movements with interest and its related components. We then tracked the facial
landmarks, e.g., corners of lips, and extracted features from each response. We
trained random forests regression models to detect the level of interest,
curiosity, and appraisals. We found a large difference between the way people
report and react to interesting visual content. The expressions in response to
images and micro-videos were not always pronounced depending on the
participants. This makes the direct detection of interest from facial
expressions a challenging problem. With this work, for the first time, we
demonstrate the feasibility of detecting cognitive appraisals from facial
expressions which will open the door for appraisal-driven emotion recognition
methods.


title:
Three-dimensional higher-spin Dirac and Weyl dispersions in the strongly
  isotropic $K_4$ crystal

abstract:
  We analyze the electronic structure in the three-dimensional (3D) crystal
formed by the $sp^2$ hybridized orbitals ($K_4$ crystal), by the tight-binding
approach based on the first-principles calculation. We discover that the bulk
Dirac-cone dispersions are realized in the $K_4$ crystal. In contrast to the
graphene, the energy dispersions of the Dirac cones are isotropic in 3D and the
pseudospin $S=1$ Dirac cones emerge at the $\Gamma$ and $H$ points of the bcc
Brillouin zone, where three bands become degenerate and merge at a single point
belonging to the $T_2$ irreducible representation. In addition, the usual
$S=1/2$ Dirac cones emerge at the $P$ point. By focusing the hoppings between
the nearest-neighbor sites, we show an analytic form of the tight-binding
Hamiltonian with a $4\times 4 $ matrix, and we give an explicit derivation of
the $S=1$ and $S=1/2$ Dirac-cone dispersions. We also analyze the effect of the
spin-orbit coupling to examine how the degeneracies at Dirac points are lifted.
At the $S=1$ Dirac points, the spin-orbit coupling lifts the energy level with
sixfold degeneracy into two energy levels with two-dimensional $\bar E_2$ and
four-dimensional $\bar F$ representations. Remarkably, all the dispersions near
the $\bar F$ point show the linear dependence in the momentum with different
velocities. We derive the effective Hamiltonian near the $\bar F$ point and
find that the band contact point is described by the $S=3/2$ Weyl point.


title:
Abundance Derivations for the Secondary Stars in Cataclysmic Variables
  from Near-Infrared Spectroscopy

abstract:
  We derive metallicities for 41 cataclysmic variables (CVs) from near-infrared
spectroscopy. We use synthetic spectra that cover the 0.8 $\mu$m $\leq \lambda
\leq$ 2.5 $\mu$m bandpass to ascertain the value of [Fe/H] for CVs with K-type
donors, while also deriving abundances for other elements. Using calibrations
for determining [Fe/H] from the $K$-band spectra of M-dwarfs, we derive more
precise values for T$_{\rm eff}$ for the secondaries in the shortest period
CVs, and examine whether they have carbon deficits. In general, the donor stars
in CVs have sub-solar metallicities. We confirm carbon deficits for a large
number of systems. CVs with orbital periods $>$ 5 hr are most likely to have
unusual abundances. We identify four CVs with CO emission. We use
phase-resolved spectra to ascertain the mass and radius of the donor in U Gem.
The secondary star in U Gem appears to have a lower {\it apparent} gravity than
a main sequence star of its spectral type. Applying this result to other CVs,
we find that the later-than-expected spectral types observed for many CV donors
is mostly an affect of inclination. All of the magnetic CVs, except the low
accretion rate polar MQ Dra, have donors with subsolar metallicities. We find
that two systems with unusual spectra, EI Psc and QZ Ser, that have large
excesses of sodium, and extreme deficits of carbon. Synthetic spectra that have
a reduced abundance of hydrogen are best able to explain the spectra of these
two objects.


title:
Adaptive dictionary based approach for background noise and speaker
  classification and subsequent source separation

abstract:
  A judicious combination of dictionary learning methods, block sparsity and
source recovery algorithm are used in a hierarchical manner to identify the
noises and the speakers from a noisy conversation between two people.
Conversations are simulated using speech from two speakers, each with a
different background noise, with varied SNR values, down to -10 dB. Ten each of
randomly chosen male and female speakers from the TIMIT database and all the
noise sources from the NOISEX database are used for the simulations. For
speaker identification, the relative value of weights recovered is used to
select an appropriately small subset of the test data, assumed to contain
speech. This novel choice of using varied amounts of test data results in an
improvement in the speaker recognition rate of around 15% at SNR of 0 dB.
Speech and noise are separated using dictionaries of the estimated speaker and
noise, and an improvement of signal to distortion ratios of up to 10% is
achieved at SNR of 0 dB. K-medoid and cosine similarity based dictionary
learning methods lead to better recognition of the background noise and the
speaker. Experiments are also conducted on cases, where either the background
noise or the speaker is outside the set of trained dictionaries. In such cases,
adaptive dictionary learning leads to performance comparable to the other case
of complete dictionaries.


title:
Searching for New Heavy Neutral Gauge Bosons using Vector Boson Fusion
  Processes at the LHC

abstract:
  New massive resonances are predicted in many extensions to the Standard Model
(SM) of particle physics and constitutes one of the most promising searches for
new physics at the LHC. We present a feasibility study to search for new heavy
neutral gauge bosons using vector boson fusion (VBF) processes, which become
especially important as the LHC probes higher collision energies. In
particular, we consider the possibility that the discovery of a $Z'$ boson may
have eluded searches at the LHC. The coupling of the $Z'$ boson to the SM
quarks can be small, and thus the $Z'$ would not be discoverable by the
searches conducted thus far. In the context of a simplified phenomenological
approach, we consider the $Z'\to\tau\tau$ and $Z'\to\mu\mu$ decay modes to show
that the requirement of a dilepton pair combined with two high $p_{T}$ forward
jets with large separation in pseudorapidity and with large dijet mass is
effective in reducing SM backgrounds. The expected exclusion bounds (at 95\%
confidence level) are $m(Z') < 1.8$ TeV and $m(Z') < 2.5$ TeV in the $\tau\tau
j_{f}j_{f}$ and $\mu\mu j_{f}j_{f}$ channels, respectively, assuming 1000
fb$^{-1}$ of 13 TeV data from the LHC. The use of the VBF topology to search
for massive neutral gauge bosons provides a discovery reach with expected
significances greater than 5$\sigma$ (3$\sigma$) for $Z'$ masses up to 1.4
(1.6) TeV and 2.0 (2.2) TeV in the $\tau\tau j_{f}j_{f}$ and $\mu\mu
j_{f}j_{f}$ channels.


title:
Achromatic light patterning and improved image reconstruction for
  parallelized RESOLFT nanoscopy

abstract:
  Fluorescence microscopy is rapidly turning into nanoscopy. Among the various
nanoscopy methods, the STED/RESOLFT super-resolution family has recently been
expanded to image even large fields of view within a few seconds. This advance
relies on using light patterns featuring substantial arrays of intensity minima
for discerning features by switching their fluorophores between on and off
states of fluorescence. Here we show that splitting the light with a grating
and recombining it in the focal plane of the objective lens renders arrays of
minima with wavelength-independent periodicity. This colour-independent
creation of periodic patterns facilitates coaligned on- and off-switching and
readout with combinations chosen from a range of wavelengths. Applying up to
three such periodic patterns on the switchable fluorescent proteins Dreiklang
and rsCherryRev1.4, we demonstrate highly parallelized, multicolour RESOLFT
nanoscopy in living cells at 60-80 nm resolution for 100 times 100 square
micrometers fields of view. We discuss the impact of novel image reconstruction
algorithms featuring background elimination by spatial bandpass filtering, as
well as strategies that incorporate complete image formation models.


title: Internet Scale Research Studies using SDL-RX

abstract:
  Medical research is one area where collecting data is usually hard and
expensive. With the launch of ResearchKit, Apple and Sage Bionetworks made
large-scale personal data collection increasingly popular via simple text-based
survey apps running on mobile phones. But such surveys can be a barrier in
terms of usability and richness of the data being collected. In this paper, we
present SDL-R X , a powerful software library designed for ResearchKit that
enables study-specific, personalized, and rich visual surveys, for both iOS and
Android platforms.


title:
Nonlinear modification of the laser noise power spectrum induced by a
  frequency-shifted optical feedback

abstract:
  In this article, we study the non-linear coupling between the stationary
(i.e. the beating modulation signal) and transient (i.e. the laser quantum
noise) dynamics of a laser subjected to frequency shifted optical feedback. We
show how the noise power spectrum and more specifically the relaxation
oscillation frequency of the laser are modified under different optical
feedback condition. Specifically we study the influence of (i) the amount of
light returning to the laser cavity and (ii) the initial detuning between the
frequency shift and intrinsic relaxation frequency. The present work shows how
the relaxation frequency is related to the strength of the beating signal and
the shape of the noise power spectrum gives an image of the Transfer Modulation
Function (i.e. of the amplification gain) of the nonlinear-laser dynamics.The
theoretical predictions, confirmed by numerical resolutions, are in good
agreements with the experimental data.


title:
Transition moments between excited electronic states from the Hermitian
  formulation of the coupled cluster quadratic response function

abstract:
  We introduce a new method for the computation of the transition moments
between the excited electronic states based on the expectation value formalism
of the coupled cluster theory [B. Jeziorski and R. Moszynski, Int. J. Quant.
Chem. 48, 161 (1993)]. The working expressions of the new method solely employ
the coupled cluster amplitudes. In the approximation adopted in the present
paper the cluster expansion is limited to single, double, and linear triple
excitations. The computed dipole transition probabilities for the
singlet-singlet and triplet-triplet transitions in alkali earth atoms agree
well with the available theoretical and experimental data. In contrast to the
existing coupled cluster response theory, the matrix elements obtained by using
our approach satisfy the Hermitian symmetry even if the excitations in the
cluster operator are truncated. As a part of the numerical evidence for the new
method, we report calculations of the transition moments between the excited
triplet states which have not yet been reported in the literature within the
coupled cluster theory. Slater-type basis sets constructed according to the
correlation-consistency principle are used in our calculations.


title: Shidlovsky's multiplicity estimate and Irrationality of zeta values

abstract:
  In this paper we follow the approach of Bertrand-Beukers (and of later work
of Bertrand), based on differential Galois theory, to prove a very general
version of Shidlovsky's lemma that applies to Pad{\'e} approximation problems
at several points, both at functional and numerical levels (i.e., before and
after evaluating at a specific point). This allows us to obtain a new proof of
the Ball-Rivoal theorem on irrationality of infinitely many values of Riemann
zeta function at odd integers, inspired by the proof of the Siegel-Shidlovsky
theorem on values of E-functions: Shidlovsky's lemma is used to replace
Nesterenko's linear independence criterion with Siegel's, so that no lower
bound is needed on the linear forms in zeta values. The same strategy provides
a new proof, and a refinement, of Nishimoto's theorem on values of L-functions
of Dirichlet characters.


title: On the radial derivative of the delta distribution

abstract:
  Possibilities for defining the radial derivative of the delta distribution
$\delta(\underline{x})$ in the setting of spherical coordinates are explored.
This leads to the introduction of a new class of continuous linear functionals
similar to but different from the standard distributions. The radial derivative
of $\delta(\underline{x})$ then belongs to that new class of so-called
signumdistributions. It is shown that these signumdistributions obey
easy-to-handle calculus rules which are in accordance with those for the
standard distributions in $\mathbb{R}^m$.


title:
Dynamic nuclear polarization and relaxation of H and D atoms in solid
  mixtures of hydrogen isotopes

abstract:
  We report on a study of Dynamic Nuclear Polarization and electron and nuclear
spin relaxation of atomic hydrogen and deuterium in solid molecular matrices of
H$_{2}$, D$_{2}$, and HD mixtures. The electron and nuclear spin relaxation
times ($T_{1e}$ and $T_{1N}$) were measured within the temperature range
0.15-2.5$\,$K in a magnetic field of 4.6 T, conditions which ensure a high
polarization of electron spins. We found that $T_{1e}$ is nearly temperature
independent in this temperature range, while $T_{1N}$ decreased by 2 orders of
magnitude. Such strong temperature dependence is typical for the nuclear Orbach
mechanism of relaxation via the electron spins. We found that the nuclear spins
of H atoms in solid D$_{2}$ and D$_{2}:$HD can be efficiently polarized by the
Overhauser effect. Pumping the forbidden transitions of H atoms also leads to
DNP, with the efficiency strongly dependent on the concentration of D atoms.
This behaviour indicates the Cross effect mechanism of the DNP and nuclear
relaxation, which turns out to be well resolved in the conditions of our
experiments. Efficient DNP of H atoms was also observed when pumping the middle
D line located in center of the ESR spectrum. This phenomenon can be explained
in terms of clusters or pairs of H atoms with strong exchange interaction.
These clusters have partially allowed transitions in the center of the ESR
spectrum and DNP may be created via the resolved Cross effect.


title: An Overview of Sustainable Green 5G Networks

abstract:
  The stringent requirements of a 1,000 times increase in data traffic and one
millisecond round trip latency have made limiting the potentially tremendous
ensuing energy consumption one of the most challenging problems for the design
of the upcoming fifth-generation (5G) networks. To enable sustainable 5G
networks, new technologies have been proposed to improve the system energy
efficiency and alternative energy sources are introduced to reduce our
dependence on traditional fossil fuels. In particular, various 5G techniques
target the reduction of the energy consumption without sacrificing the
quality-of-service. Meanwhile, energy harvesting technologies, which enable
communication transceivers to harvest energy from various renewable resources
and ambient radio frequency signals for communi- cation, have drawn significant
interest from both academia and industry. In this article, we provide an
overview of the latest research on both green 5G techniques and energy
harvesting for communication. In addition, some technical challenges and
potential research topics for realizing sustainable green 5G networks are also
identified.


title:
Gravity field and solar component of the precession rate and nutation
  coefficients of Comet 67P Churyumov-Gerasimenko

abstract:
  The aim of this study is first to determine the gravity field of the comet
67P Churyumov-Gerasimenko and second to derive the solar component of the
precession rate and nutation coefficients of the spin axis of the comet
nucleus, i.e. without the direct, usually larger, effect of outgassing. The
gravity field, and related moments of inertia, are obtained from two polyhedra,
that are provided by the OSIRIS and NAV-CAM experiments on Rosetta, and are
based on the assumption of uniform density for the comet nucleus. We also
calculate the forced precession rate as well as the nutation coefficients on
the basis of Kinoshita's theory of rotation of the rigid Earth and adapted it
to be able to indirectly include the effect of outgassing on the rotational
parameters. The 2nd degree denormalized Stokes coefficients of comet 67P C-G
turn out to be (bracketed numbers refer to second shape model) C20 = -6.74
[-7.93] * 10^-2, C22 = 2.60 [2.71] * 10^-2 consistent with normalized principal
moments of inertia A/MR^2 = 0.13 [0.11], B/MR^2 = 0.23 [0.22], with polar
moment c = C/MR^2 = 0.25, depending on the choice of the polyhedron model. The
obliquity between the rotation axis and the mean orbit normal is 52 degree, and
the precession rate only due to solar torques becomes 20-30 "/y. Oscillations
in longitude caused by the gravitational pull of the Sun turn out to be of the
order of 1', oscillations in obliquity can be estimated to be of the order of
0.5'.


title:
Measurement-induced chaos and quantum state discrimination in an
  iterated Tavis-Cummings scheme

abstract:
  A cavity quantum electrodynamical scenario is proposed for implementing a
Schr\"odinger microscope capable of amplifying differences between non
orthogonal atomic quantum states. The scheme involves an ensemble of
identically prepared two-level atoms interacting pairwise with a single mode of
the radiation field as described by the Tavis-Cummings model. By repeated
measurements of the cavity field and of one atom within each pair a
measurement-induced nonlinear quantum transformation of the relevant atomic
states can be realized. The intricate dynamical properties of this nonlinear
quantum transformation, which exhibits measurement-induced chaos, allows
approximate orthogonalization of atomic states by purification after a few
iterations of the protocol, and thus the application of the scheme for quantum
state discrimination.


title: Weak eigenstate thermalization with large deviation bound

abstract:
  We investigate the eigenstate thermalization hypothesis (ETH) for a
translationally invariant quantum spin system on the $d$-dimensional cubic
lattice under the periodic boundary conditions. It is known that the ETH holds
in this model for typical energy eigenstates in the sense that the standard
deviation of the expectation values of a local observable in the energy
eigenstates within the microcanonical energy shell vanishes in the
thermodynamic limit, which is called the weak ETH. Here, it is remarked that
the diagonal elements of a local observable in the energy representation shows
the large deviation behavior. This result implies that the fraction of atypical
eigenstates which do not represent thermal equilibrium is exponentially small.


title: Density and spacings for the energy levels of quadratic Fermi operators

abstract:
  The work presents a proof of convergence of the density of energy levels to a
Gaussian distribution for a wide class of quadratic forms of Fermi operators.
This general result applies also to quadratic operators with disorder, e.g.,
containing random coefficients. The spacing distribution of the unfolded
spectrum is investigated numerically. For generic systems the level spacings
behave as the spacings in a Poisson process. Level clustering persists in
presence of disorder.


title: Bandgap measurement of high refractive index materials by off-axis EELS

abstract:
  In the present work, Cs aberration corrected and monochromated scanning
transmission electron microscopy electron energy loss spectroscopy STEM-EELS
has been used to explore experimental set-ups that allows bandgaps of high
refractive index materials to be determined. Semi-convergence and -collection
angles in the micro-radian range were combined with off-axis or dark field EELS
to avoid relativistic losses and guided light modes in the low loss range to
contribute to the acquired EEL spectra. Off-axis EELS further suppressed the
zero loss peak and the tail of the zero loss peak. The bandgap of several
GaAs-based materials were successfully determined by direct inspection and
without any background subtraction of the EEL spectra. The presented set-up
does not require that the acceleration voltage is set to below the Cerenkov
limit and can be applied over the entire acceleration voltage range of modern
TEMs and for a wide range of specimen thicknesses.


title: Thermodynamics and emergent universe

abstract:
  We show that in the isentropic scenario the first order thermodynamical
particle creation model gives an emergent universe solution even when the
chemical potential is non-zero. However there exists no emergent universe
scenario in the second order non-equilibrium theory for the particle creation
model. We then point out a correspondence between the particle creation model
with barotropic equation of state and the equation of state giving rise to an
emergent universe without particle creation in spatially flat FRW cosmology.


title:
Moduli spaces of framed symplectic and orthogonal bundles on P2 and the
  K-theoretic Nekrasov partition functions

abstract:
  Let $K$ be the compact Lie group $USp(N/2)$ or $SO(N, R)$. Let $M^K_n$ be the
moduli space of framed K-instantons over $S^4$ with the instanton number $n$.
By Donaldson (1984), $M^K_n$ is endowed with a natural scheme structure. It is
a Zariski open subset of a GIT quotient of $\mu^{-1}(0)$, where $\mu$ is a
holomorphic moment map such that $\mu^{-1}(0)$ consists of the ADHM data. The
purpose of the paper is to study the geometric properties of $\mu^{-1}(0)$ and
its GIT quotient, such as complete intersection, irreducibility, reducedness
and normality. If $K=USp(N/2)$ then $\mu$ is flat and $\mu^{-1}(0)$ is an
irreducible normal variety for any $n$ and even $N$. If $K = SO(N, R)$ the
similar results are proven for low $n$ and $N$. As an application one can
obtain a mathematical interpretation of the K-theoretic Nekrasov partition
function of Nekrasov and Shadchin (2004).


title:
General Relativity and Cosmology: Unsolved Questions and Future
  Directions

abstract:
  For the last 100 years, General Relativity (GR) has taken over the
gravitational theory mantle held by Newtonian Gravity for the previous 200
years. This article reviews the status of GR in terms of its self-consistency,
completeness, and the evidence provided by observations, which have allowed GR
to remain the champion of gravitational theories against several other classes
of competing theories. We pay particular attention to the role of GR and
gravity in cosmology, one of the areas in which one gravity dominates and new
phenomena and effects challenge the orthodoxy. We also review other areas where
there are likely conflicts pointing to the need to replace or revise GR to
represent correctly observations and consistent theoretical framework.
Observations have long been key both to the theoretical liveliness and
viability of GR. We conclude with a discussion of the likely developments over
the next 100 years.


title:
First-principles Study of Rashba Effect in Ultra-thin Bismuth Surface
  Alloys

abstract:
  We performed density functional calculations for ultra-thin bismuth surface
alloys: surface alloys of bismuth and face-centered cubic metals
Bi/$M$(111)-$(\sqrt{3}\times\sqrt{3})R30\deg$ ($M$=Cu, Ag, Au, Ni, Co, and Fe).
Our calculated Rashba parameters for the Bi/Ag are consistent with the previous
experimental and theoretical results. We predicted a trend in the Rashba
coefficients $\alpha_R$ of bands around the Fermi energy for noble metals as
follows: Bi/Ag > Bi/Cu > Bi/Au. As for the transition metals, there is a trend
in $\alpha_R$: Bi/Ni > Bi/Co > Bi/Fe. Our finding may lead to design efficient
spin-charge conversion materials.


title: Five Basic Concepts of Axiomatic Rewriting Theory

abstract:
  In this invited talk, I will review five basic concepts of Axiomatic
Rewriting Theory, an axiomatic and diagrammatic theory of rewriting started 25
years ago in a LICS paper with Georges Gonthier and Jean-Jacques L\'evy, and
developed along the subsequent years into a full-fledged 2-dimensional theory
of causality and residuation in rewriting. I will give a contemporary view on
the theory, informed by my later work on categorical semantics and
higher-dimensional algebra, and also indicate a number of current research
directions in the field.


title: Gravitational luminosity of a hot plasma in R^2 gravity

abstract:
  The R^{2}-gravity contribution to energy loss of a hot plasma due to the
gravitational bremsstrahlung is calculated in the linearized theory on the
basis of classical Coulomb scattering of plasma constituents in small-angle
scattering approximation. The explicit dependence of the gravitational
luminosity on the plasma temperature is derived and its relevance to the
Einstein gravity is demonstrated. The result when applied to the Sun as a hot
plasma, shows very good agreement with available data.


title:
Real-time Predictive Analytics for Improving Public Transportation
  Systems' Resilience

abstract:
  Public transit systems are a critical component of major metropolitan areas.
However, in the face of increasing demand, most of these systems are operating
close to capacity. Under normal operating conditions, station crowding and
boarding denial are becoming a major concern for transit agencies. As such, any
disruption in service will have even more severe consequences, affecting huge
number of passengers. Considering the aging infrastructure of many large
cities, such as New York and London, these disruptions are to be expected,
amplifying the need for better demand management and strategies to deal with
congested transit facilities. Opportunistic sensors such as smart cards (AFC),
automatic vehicle location systems (AVL), GPS, etc. provide a wealth of
information about system's performance and passengers' trip making patterns. We
develop a hybrid data/model-driven decision support system, using real-time
predictive models, to help transit operators manage and respond proactively to
disruptions and mitigate consequences in a timely fashion. These models include
station arrival and origin-destination predictions in real-time to help transit
agencies, and predictive information systems for assisting passengers' trip
making decisions.


title: Bit-permuted coded modulation for polar codes

abstract:
  We consider the problem of using polar codes with higher order modulation
over AWGN channels. Unlike prior work, we focus on using modulation independent
polar codes. That is, the polar codes are not re-designed based on the
modulation used. Instead, we propose bit-permuted coded modulation (BPCM): a
technique for using the multilevel coding (MLC) approach for an arbitrary polar
code. The BPCM technique exploits a natural connection between MLC and polar
codes. It involves applying bit permutations prior to mapping the polar code to
a higher order modulation. The bit permutations are designed, via density
evolution, to match the rates provided by various bit levels of the higher
order modulation to that of the polar code.
  We demonstrate performance of the BPCM technique using link simulations and
density evolution for the AWGN channel. We compare the BPCM technique with the
bit-interleaved coded modulation (BICM) technique. When using polar codes
designed for BPSK modulation, we show gains for BPCM over BICM with random
interleaver of up to 0.2 dB, 0.7 dB and 1.4 dB for 4-ASK, 8-ASK, and 16-ASK
respectively.


title: Universally and existentially definable subsets of global fields

abstract:
  We show that rings of $S$-integers of a global function field $K$ of odd
characteristic are first-order universally definable in $K$. This extends work
of Koenigsmann and Park who showed the same for $\mathbb{Z}$ in $\mathbb{Q}$
and the ring of integers in a number field, respectively.
  We also give another proof of a theorem of Poonen and show that the set of
non-squares in a global field of characteristic $\neq 2$ is diophantine.
Finally, we show that the set of pairs $(x,y)$ in $(K^{\times})^2$ such that
$x$ is not a norm in $K(\sqrt{y})$ is diophantine over $K$ for any global field
$K$ of characteristic $\neq 2$.


title: Brownian motion of a circle swimmer in a harmonic trap

abstract:
  We study the dynamics of a Brownian circle swimmer with a time-dependent
self-propulsion velocity in an external temporally varying harmonic potential.
For several situations, the noise-free swimming paths, the noise-averaged mean
trajectories, and the mean square displacements are calculated analytically or
by computer simulation. Based on our results, we discuss optimal swimming
strategies in order to explore a maximum spatial range around the trap center.
In particular, we find a resonance situation for the maximum escape distance as
a function of the various frequencies in the system. Moreover, the influence of
the Brownian noise is analyzed by comparing noise-free trajectories at zero
temperature with the corresponding noise-averaged trajectories at finite
temperature. The latter reveal various complex self-similar spiral or
rosette-like patterns. Our predictions can be tested in experiments on
artificial and biological microswimmers under dynamical external confinement.


title:
Identification of Piecewise Affine State-Space Models via Expectation
  Maximization

abstract:
  This paper deals with the identification of piecewise affine state-space
models. These models are obtained by partitioning the state or input domain
into a finite number of regions and by considering affine submodels in each
region. The proposed framework uses the Expectation Maximization (EM) algorithm
to identify the parameters of the model. In most of the current literature, a
discrete random variable with a discrete transition density is introduced to
describe the transition between each submodel, leading to a further
approximation of the dynamical system by a jump Markov model. On the contrary,
we use the cumulative distribution function (CDF) to compute the probability of
each submodel given the measurement at that time step. Then, given the submodel
at each time step the latent state is estimated using the Kalman smoother.
Subsequently, the parameters are estimated by maximizing a surrogate function
for the likelihood. The performance of the proposed method is illustrated using
the simulated model of the JAS 39 Gripen aircraft.


title:
Simultaneous control of the Dzyaloshinskii-Moriya interaction and
  magnetic anisotropy in nanomagnetic trilayers

abstract:
  Magneto-optical Kerr effect (MOKE) microscopy measurements of magnetic bubble
domains demonstrate that Ar+ irradiation around 100 eV can tune the
Dzyaloshinskii-Moriya interaction (DMI) in Pt/Co/Pt trilayers. Varying the
irradiation energy and dose changes the DMI sign and magnitude separately from
the magnetic anisotropy, allowing tuning of the DMI while holding the coercive
field constant. This simultaneous control emphasizes the different physical
origins of these effects. To accurately measure the DMI, we propose and apply a
physical model for a poorly understood peak in domain wall velocity at zero
in-plane field. The ability to tune the DMI with the spatial resolution of the
Ar+ irradiation enables new fundamental investigations and technological
applications of chiral nanomagnetics.


title:
Strain hardening-softening oscillations induced by nanoindentation in
  bulk solids

abstract:
  Nanoindentation is a widely used method for sensitive exploration of the
mechanical properties of micromechanical systems. We derived an empirical
analysis technique to extract stress-strain field gradient and divergence
representations from nanoindentation measurements. With this approach local
gradients and heterogeneities can be discovered to obtain more detail about the
sample's microstructure, thus enhancing the analytic capacity of the
nanoindentation technique. We analysed nanoindentation tests of bulk solid
substrates, namely bearing and tooling steel, and fused silica. Oscillations of
the stress-strain field gradient and divergence induced in the subsurface layer
by the nanoindentation experiment were revealed. The oscillations were
especially prominent in single measurements at low indentation depths (< 100
nm), whereas they were concealed in the averaged datasets. The amplitude of
stress-strain field divergence oscillations decayed as a sublinear power-law
when the indenter approached deeper atomic layers, with an exponent -0.9 for
the steel and -0.8 for the fused silica. The oscillations were interpreted as
alternating strain hardening-softening cycles induced in the subsurface layers
under the indenter load. A selective assessment of elastic and plastic
stress-strain field components indicated an elastic-plastic deformation process
where the normal strain is transformed into the shear strain leading to a
plastic deformation.


title:
R\'esolution des syst\`emes polynomiaux: un solveur bas\'e sur les
  matrices de Bezout

abstract:
  We propose a method to compute the numerical solutions of a polynomial system
in complete intersection. This algorithm makes use of Bezout matrices and need
only linear algebra computations. All the calculations can be done in floating
point arithmetic. A complete implementation of the algorithm is provided.


title: Isogeny graphs of ordinary abelian varieties

abstract:
  Fix a prime number $\ell$. Graphs of isogenies of degree a power of $\ell$
are well-understood for elliptic curves, but not for higher-dimensional abelian
varieties. We study the case of absolutely simple ordinary abelian varieties
over a finite field. We analyse graphs of so-called $\mathfrak l$-isogenies,
resolving that they are (almost) volcanoes in any dimension. Specializing to
the case of principally polarizable abelian surfaces, we then exploit this
structure to describe graphs of a particular class of isogenies known as
$(\ell, \ell)$-isogenies: those whose kernels are maximal isotropic subgroups
of the $\ell$-torsion for the Weil pairing. We use these two results to write
an algorithm giving a path of computable isogenies from an arbitrary absolutely
simple ordinary abelian surface towards one with maximal endomorphism ring,
which has immediate consequences for the CM-method in genus 2, for computing
explicit isogenies, and for the random self-reducibility of the discrete
logarithm problem in genus 2 cryptography.


title: Plasmon-assisted high-harmonic generation in graphene

abstract:
  High-harmonic generation (HHG) in condensed-matter systems is both a source
of fundamental insight into quantum electron motion and a promising candidate
to realize compact ultraviolet and ultrafast light sources. Here we argue that
the large light intensity required for this phenomenon to occur can be reached
by exploiting localized plasmons in conducting nanostructures. In particular,
we demonstrate that doped graphene nanostructures combine a strong plasmonic
near-field enhancement and a pronounced intrinsic nonlinearity that result in
efficient broadband HHG within a single material platform. We extract this
conclusion from time-domain simulations using two complementary nonperturbative
approaches based on atomistic one-electron density-matrix and massless
Dirac-fermion Bloch-equation pictures. High harmonics are predicted to be
emitted with unprecedentedly large intensity by tuning the incident light to
the localized plasmons of ribbons and finite islands. In contrast to atomic
systems, we observe no cutoff in harmonic order. Our results support the strong
potential of nanostructured graphene as a robust, electrically tunable platform
for HHG.


title: Entropy of Causal Horizons

abstract:
  We analyze spacetimes with horizons and study the thermodynamic aspects of
causal horizons, suggesting that the resemblance between gravitational and
thermodynamic systems has a deeper quantum mechanical origin. We find that the
observer dependence of such horizons is a direct consequence of associating a
temperature and entropy to a spacetime. The geometrical picture of a horizon
acting as a one-way membrane for information flow can be accepted as a natural
interpretation of assigning a quantum field theory to a spacetime with
boundary, ultimately leading to a close connection with thermodynamics.


title: The multi-stripe travelling salesman problem

abstract:
  In the classical Travelling Salesman Problem (TSP), the objective function
sums the costs for travelling from one city to the next city along the tour. In
the q-stripe TSP with q larger than 1, the objective function sums the costs
for travelling from one city to each of the next q cities along the tour. The
resulting q-stripe TSP generalizes the TSP and forms a special case of the
quadratic assignment problem. We analyze the computational complexity of the
q-stripe TSP for various classes of specially structured distance matrices. We
derive NP-hardness results as well as polyomially solvable cases. One of our
main results generalizes a well-known theorem of Kalmanson from the classical
TSP to the q-stripe TSP.


title:
Actions affines isom\'etriques propres des groupes hyperboliques sur des
  quotients d'espaces $\ell^p$

abstract:
  We prove that any hyperbolic group admits a proper affine isometric action on
a quotient space of a $\ell^p$ Banach space, for all $p>1$ sufficiently close
to 1.


title:
Cosmological self-tuning and local solutions in generalized Horndeski
  theories

abstract:
  We study both the cosmological self-tuning and the local predictions (inside
the Solar system) of the most general shift-symmetric beyond Horndeski theory.
We first show that the cosmological self-tuning is generic in this class of
theories: By adjusting a mass parameter entering the action, a large bare
cosmological constant can be effectively reduced to a small observed one.
Requiring then that the metric should be close enough to the Schwarzschild
solution in the Solar system, to pass the experimental tests of general
relativity, and taking into account the renormalization of Newton's constant,
we select a subclass of models which presents all desired properties: It is
able to screen a big vacuum energy density, while predicting an exact
Schwarzschild-de Sitter solution around a static and spherically symmetric
source. As a by-product of our study, we identify a general subclass of beyond
Horndeski theory for which regular self-tuning black hole solutions exist, in
presence of a time-dependent scalar field. We discuss possible future
development of the present work.


title: Optimal spectral transportation with application to music transcription

abstract:
  Many spectral unmixing methods rely on the non-negative decomposition of
spectral data onto a dictionary of spectral templates. In particular,
state-of-the-art music transcription systems decompose the spectrogram of the
input signal onto a dictionary of representative note spectra. The typical
measures of fit used to quantify the adequacy of the decomposition compare the
data and template entries frequency-wise. As such, small displacements of
energy from a frequency bin to another as well as variations of timber can
disproportionally harm the fit. We address these issues by means of optimal
transportation and propose a new measure of fit that treats the frequency
distributions of energy holistically as opposed to frequency-wise. Building on
the harmonic nature of sound, the new measure is invariant to shifts of energy
to harmonically-related frequencies, as well as to small and local
displacements of energy. Equipped with this new measure of fit, the dictionary
of note templates can be considerably simplified to a set of Dirac vectors
located at the target fundamental frequencies (musical pitch values). This in
turns gives ground to a very fast and simple decomposition algorithm that
achieves state-of-the-art performance on real musical data.


title:
Transition from Solitons to Solitary Waves in the Fermi-Pasta-Ulam
  Lattice

abstract:
  In this paper, we study the smooth transition from solitons to solitary waves
in localization, relation between energy and velocity, propagation and
scattering property in the Fermi-Pasta-Ulam lattice analytically and
numerically. A soliton is a very stable solitary wave that retains its
permanent structure after interacting with other solitary waves. A soliton
exists when the energy is small, and it becomes a solitary wave when the energy
increases to the threshold. The transition could help to understand the
distinctly different heat conduction behaviors of the Fermi-Pasta-Ulam lattice
at low and high temperature.


title: Fermi's Paradox Is a Daunting Problem---Under Whatever Label

abstract:
  Gray (2015) argued that the Fermi paradox (FP) is a misnomer, and it is not a
valid paradox. Gray also speculated that the argument was misattributed to
Fermi, whose lunchtime remarks did not pertain to the existence of
extraterrestrial intelligence, but to the feasibility of interstellar travel.
Instead, the paradox is ascribed to Hart and Tipler, and it is further
suggested that the paradox is not a real problem or research subject and should
not be used in debates about SETI projects. The arguments given are
unpersuasive, ahistorical, and, in at least one instance, clearly hinge on
literalistic and uncharitable reading of evidence. Instead, I argue the
following three points: (i) Contrary to Gray's assertion, the historical issue
of naming of ideas or concepts is completely divorced from their epistemic
status. (ii) FP is easily and smoothly generalized into the Great Silence
paradox, so it makes no sense either theoretically or empirically to separate
the two. (iii) In sharp contrast to the main implication of Gray's paper, FP
has become more aggravated lately due to advances in astrobiology.


title:
On groups elementarily equivalent to a group of triangular matrices
  $T_n(R)$

abstract:
  In this paper we investigate the structure of groups elementarily equivalent
to the group $T_n(R)$ of all invertible upper triangular $n\times n$ matrices,
where $n\geq 3$ and $R$ is a characteristic zero integral domain. In particular
we give both necessary and sufficient conditions for a group being elementarily
equivalent to $T_n(R)$ where $R$ is a characteristic zero algebraically closed
field, a real closed field, a number field, or the ring of integers of a number
field.


title: Beyond p values: practical methods for analyzing uncertainty in research

abstract:
  This article explains, and discusses the merits of, three approaches for
analyzing the certainty with which statistical results can be extrapolated
beyond the data gathered. Sometimes it may be possible to use more than one of
these approaches. (1) If there is an exact null hypothesis which is credible
and interesting (usually not the case), researchers should cite a p value
(significance level), although jargon is best avoided. (2) If the research
result is a numerical value, researchers should cite a confidence interval. (3)
If there are one or more hypotheses of interest, it may be possible to adapt
the methods used for confidence intervals to derive an "estimated probability"
for each. Under certain circumstances these could be interpreted as Bayesian
posterior probabilities. These estimated probabilities can easily be worked out
from the p values and confidence intervals produced by packages such as SPSS.
Estimating probabilities for hypotheses means researchers can give a direct
answer to the question "How certain can we be that this hypothesis is right?".


title: Distinguishability and many-particle interference

abstract:
  Quantum interference of two independent particles in pure quantum states is
fully described by the particles' distinguishability: the closer the particles
are to being identical, the higher the degree of quantum interference. When
more than two particles are involved, the situation becomes more complex and
interference capability extends beyond pairwise distinguishability, taking on a
surprisingly rich character. Here, we study many-particle interference using
three photons. We show that the distinguishability between pairs of photons is
not sufficient to fully describe the photons' behaviour in a scattering
process, but that a collective phase, the triad phase, plays a role. We are
able to explore the full parameter space of three-photon interference by
generating heralded single photons and interfering them in a fibre tritter.
Using multiple degrees of freedom - temporal delays and polarisation - we
isolate three-photon interference from two-photon interference. Our experiment
disproves the view that pairwise two-photon distinguishability uniquely
determines the degree of non-classical many-particle interference.


title: Progress on the three-particle quantization condition

abstract:
  We report progress on extending the relativistic model-independent
quantization condition for three particles, derived previously by two of us, to
a broader class of theories, as well as progress on checking the formalism. In
particular, we discuss the extension to include the possibility of 2->3 and
3->2 transitions and the calculation of the finite-volume energy shift of an
Efimov-like three-particle bound state. The latter agrees with the results
obtained previously using non-relativistic quantum mechanics.


title:
Liouville-type theorems on the complete gradient shrinking Ricci
  solitons

abstract:
  We prove that there does not exist non-constant positive $f$-harmonic
function on the complete gradient shrinking Ricci solitons. We also prove the
$L^{p}(p\geq 1 \ {\rm or}\ 0<p\leq 1)$ Liouville theorems on the complete
gradient shrinking Ricci solitons.


title: Proceedings of the Data For Good Exchange 2016

abstract:
  These are the proceedings of the Data For Good Exchange 2016, which was held
in New York, NY, on September 26th 2016.


title:
Equation system describing the radiation intensity and the air motion
  with the water phase transition

abstract:
  In this paper we consider the equation system describing the motion of the
air and the variation of the radiation intensity and the quantity of water
droplets in the air, including also the process of water phase transition.
Under a suitable condition we prove the existence and uniqueness of the local
solution. By eliminating the approximation by regularization of vapor density
and by including the equation of radiation, this result improves previous ones.


title: Hochschild homology and cohomology of down-up algebras

abstract:
  We present a detailed computation of the cyclic and the Hochschild homology
and cohomology of generic and 3-Calabi-Yau homogeneous down-up algebras. This
family was defined by Benkart and Roby in their study of differential posets.
Our calculations are completely explicit, by making use of the Koszul bimodule
resolution and arguments similar to those used by the second and third authors
for Yang-Mills algebras.


title:
On elementary equivalence of rings with a finitely generated additive
  group

abstract:
  In this paper we provide a complete algebraic characterization of elementary
equivalence of rings with a finitely generated additive group in the language
of pure rings. The rings considered are arbitrary otherwise.


title:
Orbital and Superorbital Monitoring of the Be/X-ray binary A0538-66:
  constraints on the system parameters

abstract:
  We combine the decade long photometry of the Be/X-ray binary system A0538-66
provided by the MACHO and OGLE IV projects with high resolution SALT
spectroscopy to provide detailed constraints on the orbital parameters and
system properties. The ~420d superorbital modulation is present throughout, but
has reduced in amplitude in recent years. The well-defined 16.6409d orbital
outbursts, which were a strong function of superorbital phase in the MACHO data
(not occurring at all at superorbital maximum), are present throughout the OGLE
IV coverage. However, their amplitude reduces during superorbital maximum. We
have refined the orbital period and ephemeris of the optical outburst based on
~25 yrs light curves to HJD = 2455674.48 +/- 0.03 + n*16.6409 +/- 0.0003d. Our
SALT spectra reveal a B1 III star with vsini of 285 km/s from which we have
derived an orbital radial velocity curve which confirms the high eccentricity
of e = 0.72 +/- 0.14. Furthermore, the mass function indicates that, unless the
neutron star far exceeds the canonical 1.44 Msun, the donor must be
significantly undermassive for its spectral type. We discuss the implications
of the geometry and our derived orbital solution on the observed behaviour of
the system.


title: Lieb-Thirring Inequalities for Complex Finite Gap Jacobi Matrices

abstract:
  We establish Lieb-Thirring power bounds on discrete eigenvalues of Jacobi
operators for Schatten class complex perturbations of periodic and more
generally finite gap Jacobi matrices.


title: Subleading power corrections in radiative leptonic $B$ decay

abstract:
  I discuss the two-particle subleading power corrections in radiative leptonic
$B \to \gamma \ell \nu$ decay at next-to-leading order in $\alpha_s$ with the
dispersion approach. Employing the method of regions, factorization of the $B
\to \gamma^{\ast}$ form factors is demonstrated explicitly, at one loop, for a
space-like hard-collinear photon. The two-particle soft (end-point)
contribution is shown to be suppressed by one power of $\Lambda/m_b$, in the
heavy quark limit, compared with the leading power contribution computed from
QCD factorization. I further report the recent calculation on the
three-particle subleading power contribution to the on-shell $B \to \gamma$
form factors at tree level and demonstrate that the "soft" and the "hard"
three-particle corrections are of the same power, in contrast to the
two-particle counterparts, as already speculated from the rapidity divergence
in the corresponding factorization formulae. Phenomenological implications of
the subleading power contributions to the $B \to \gamma \ell \nu$ amplitude are
also addressed in detail, focusing on the determination of the inverse moment
of the leading-twist $B$-meson distribution amplitude.


title: Phototaxis of synthetic microswimmers in optical landscapes

abstract:
  Many microorganisms, with phytoplankton and zooplankton as prominent
examples, display phototactic behaviour, that is, the ability to perform
directed motion within a light gradient. Here we experimentally demonstrate
that sensing of light gradients can also be achieved in a system of synthetic
photo-activated microparticles being exposed to an inhomogeneous laser field.
We observe a strong orientational response of the particles because of
diffusiophoretic torques, which in combination with an intensity-dependent
particle motility eventually leads to phototaxis. Since the aligning torques
saturate at high gradients, a strongly rectified particle motion is found even
in periodic asymmetric intensity landscapes. Our results are in excellent
agreement with numerical simulations of a minimal model and should similarly
apply to other particle propulsion mechanisms. Because light fields can be
easily adjusted in space and time, this also allows to extend our approach to
dynamical environments.


title: Lectures on Higher Structures in M-Theory

abstract:
  These are notes for four lectures on higher structures in M-theory as
presented at workshops at the Erwin Schroedinger Institute and Tohoku
University. The first lecture gives an overview of systems of multiple
M5-branes and introduces the relevant mathematical structures underlying a
local description of higher gauge theory. In the second lecture, we develop the
corresponding global picture. A construction of non-abelian superconformal
gauge theories in six dimensions using twistor spaces is discussed in the third
lecture. The last lecture deals with the problem of higher quantization and its
relation to loop space. An appendix summarizes the relation between 3-Lie
algebras and Lie 2-algebras.


title:
A Spatio-Temporal Modeling Approach for Weather Radar Reflectivity Data
  and Its Applications in Tropical Southeast Asia

abstract:
  Weather radar echoes, correlated in both space and time, are the most
important input data for short-term precipitation forecast. Motivated by real
datasets, this paper is concerned with the spatio-temporal modeling of
two-dimensional radar reflectivity fields from a sequence of radar images.
Under a Lagrangian integration scheme, we model the radar reflectivity data by
a spatio-temporal conditional autoregressive process which is driven by two
hidden sub-processes. The first sub-process is the dynamic velocity field which
determines the motion of the weather system, while the second sub-process
governs the growth or decay of the strength of radar reflectivity. The proposed
method is demonstrated, and compared with existing methods, using the real
radar data collected from the tropical southeast Asia. Note that, since the
tropical storms are known to be highly chaotic and extremely difficult to be
predicted, we only focus on the modeling of reflectivity data within a
short-period of time and consider the short-term prediction problem based on
the proposed model. This is often referred to as the nowcasting issue in the
meteorology society.


title:
Repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li
  atoms

abstract:
  We employ radio-frequency spectroscopy to investigate a polarized
spin-mixture of ultracold ${}^6$Li atoms close to a broad Feshbach scattering
resonance. Focusing on the regime of strong repulsive interactions, we observe
well-defined coherent quasiparticles even for unitarity-limited interactions.
We characterize the many-body system by extracting the key properties of
repulsive Fermi polarons: the energy $E_+$, the effective mass $m^*$, the
residue $Z$ and the decay rate $\Gamma$. Above a critical interaction, $E_+$ is
found to exceed the Fermi energy of the bath while $m^*$ diverges and even
turns negative, thereby indicating that the repulsive Fermi liquid state
becomes energetically and thermodynamically unstable.


title: Extension of the MURaM radiative MHD code for coronal simulations

abstract:
  We present a new version of the MURaM radiative MHD code that allows for
simulations spanning from the upper convection zone into the solar corona. We
implemented the relevant coronal physics in terms of optically thin radiative
loss, field aligned heat conduction and an equilibrium ionization equation of
state. We artificially limit the coronal Alfv{\'e}n and heat conduction speeds
to computationally manageable values using an approximation to
semi-relativistic MHD with an artificially reduced speed of light (Boris
correction). We present example solutions ranging from quiet to active Sun in
order to verify the validity of our approach. We quantify the role of numerical
diffusivity for the effective coronal heating. We find that the (numerical)
magnetic Prandtl number determines the ratio of resistive to viscous heating
and that owing to the very large magnetic Prandtl number of the solar corona,
heating is expected to happen predominantly through viscous dissipation. We
find that reasonable solutions can be obtained with values of the reduced speed
of light just marginally larger than the maximum sound speed. Overall this
leads to a fully explicit code that can compute the time evolution of the solar
corona in response to photospheric driving using numerical time steps not much
smaller than $0.1$ seconds. Numerical simulations of the coronal response to
flux emergence covering a time span of a few days are well within reach using
this approach.


title: Averaging of highly-oscillatory transport equations

abstract:
  In this paper, we develop a new strategy aimed at obtaining high-order
asymptotic models for transport equations with highly-oscillatory solutions.
The technique relies upon recent developments averaging theory for ordinary
differential equations, in particular normal form expansions in the vanishing
parameter. Noteworthy, the result we state here also allows for the complete
recovery of the exact solution from the asymptotic model. This is done by
solving a companion transport equation that stems naturally from the change of
variables underlying high-order averaging. Eventually, we apply our technique
to the Vlasov equation with external electric and magnetic fields. Both
constant and non-constant magnetic fields are envisaged, and asymptotic models
already documented in the literature and re-derived using our methodology. In
addition, it is shown how to obtain new high-order asymptotic models.


title: Broken current anomalous dimensions, conformal manifolds and RG flows

abstract:
  We consider deformations of a conformal field theory that explicitly break
some global symmetries of the theory. If the deformed theory is still a
conformal field theory, one can exploit the constraints put by conformal
symmetry to compute broken currents anomalous dimensions. We consider several
instances of this scenario, using field theory techniques and also holographic
ones, where necessary. Field theoretical methods suffice to discuss examples of
symmetry-breaking deformations of the $O(N )$ model in $d=4-\epsilon$
dimensions. Holography is instrumental, instead, for computing current
anomalous dimensions in $\beta$-deformed superconformal field theories, and in
a class of supersymmetric RG flows at large $N$.


title: On special Rees matrix semigroups over semigroups

abstract:
  In this paper we focus on Rees $I\times \Lambda$ matrix semigroups without
zero over a semigroup $S$ with $\Lambda\times I$ sandwich matrix $P$, where $I$
is a singleton, $\Lambda$ is the factor semigroup of $S$ modulo the kernel
$\theta_S$ of the right regular representation of $S$, and $P$ is a choice
function on the collection of all $\theta _S$-classes of $S$. We describe the
kernel of the right regular representation of this type of Rees matrix
semigroups, and prove embedding theorems on them. Motivated by one of embedding
theorems, we show how right commutative right cancellative semigroups can be
constructed. We define the concept of a right regular sequence of semigroups,
and show that every congruence on an arbitrary semigroup defines such a
sequence.


title:
Stepping Stabilization Using a Combination of DCM Tracking and Step
  Adjustment

abstract:
  In this paper, a method for stabilizing biped robots stepping by a
combination of Divergent Component of Motion (DCM) tracking and step adjustment
is proposed. In this method, the DCM trajectory is generated, consistent with
the predefined footprints. Furthermore, a swing foot trajectory modification
strategy is proposed to adapt the landing point, using DCM measurement. In
order to apply the generated trajectories to the full robot, a Hierarchical
Inverse Dynamics (HID) is employed. The HID enables us to use different
combinations of the DCM tracking and step adjustment for stabilizing different
biped robots. Simulation experiments on two scenarios for two different
simulated robots, one with active ankles and the other with passive ankles, are
carried out. Simulation results demonstrate the effectiveness of the proposed
method for robots with both active and passive ankles.


title: On the Worst-case Communication Overhead for Distributed Data Shuffling

abstract:
  Distributed learning platforms for processing large scale data-sets are
becoming increasingly prevalent. In typical distributed implementations, a
centralized master node breaks the data-set into smaller batches for parallel
processing across distributed workers to achieve speed-up and efficiency.
Several computational tasks are of sequential nature, and involve multiple
passes over the data. At each iteration over the data, it is common practice to
randomly re-shuffle the data at the master node, assigning different batches
for each worker to process. This random re-shuffling operation comes at the
cost of extra communication overhead, since at each shuffle, new data points
need to be delivered to the distributed workers.
  In this paper, we focus on characterizing the information theoretically
optimal communication overhead for the distributed data shuffling problem. We
propose a novel coded data delivery scheme for the case of no excess storage,
where every worker can only store the assigned data batches under processing.
Our scheme exploits a new type of coding opportunity and is applicable to any
arbitrary shuffle, and for any number of workers. We also present an
information theoretic lower bound on the minimum communication overhead for
data shuffling, and show that the proposed scheme matches this lower bound for
the worst-case communication overhead.


title: Complexity of Triangular Representations of Algebraic Sets

abstract:
  Triangular decomposition is one of the standard ways to represent the radical
of a polynomial ideal. A general algorithm for computing such a decomposition
was proposed by A. Szanto. In this paper, we give the first complete bounds for
the degrees of the polynomials and the number of components in the output of
the algorithm, providing explicit formulas for these bounds.


title: Gravitational Wave Memory: A New Approach to Study Modified Gravity

abstract:
  It is well known that two types of gravitational wave memory exist in general
relativity (GR): the linear memory and the non-linear, or Christodoulou memory.
These effects, especially the latter, depend on the specific form of Einstein
equation. It can then be speculated that in modified theories of gravity, the
memory can differ from the GR prediction, and provides novel phenomena to study
these theories. We support this speculation by considering scalar-tensor
theories, for which we find two new types of memory: the T memory and the S
memory, which contribute to the tensor and scalar components of gravitational
wave, respectively. In particular, the former is caused by the burst of energy
carried away by scalar radiation, while the latter is intimately related to the
no scalar hair property of black holes in scalar-tensor gravity. We estimate
the size of these two types of memory in gravitational collapses, and formulate
a detection strategy for the S memory, which can be singled out from tensor
gravitational waves. We show that (i) the S memory exists even in spherical
symmetry, and is observable under current model constraints, and (ii) while the
T memory is usually much weaker than the S memory, it can become comparable in
the case of spontaneous scalarization.


title: Explorations of Dusty Debris Disk Geometry

abstract:
  As the sample of white dwarfs with signatures of planetary systems has grown,
statistical studies have begun to suggest our picture of compact debris disk
formation from disrupted planetary bodies is incomplete. Here we present the
results of an effort to extend the preferred dust disk model introduced by
\citet{jur03} to include elliptical geometries. We apply this model the
observed distribution of fractional infrared luminosities, and explore the
difference in preferred parameter spaces for a circular and highly elliptical
model on a well-studied dusty white dwarf.


title:
Sprout: A functional caching approach to minimize service latency in
  erasure-coded storage

abstract:
  Modern distributed storage systems often use erasure codes to protect against
disk and node failures to increase reliability, while trying to meet the
latency requirements of the applications and clients. Storage systems may have
caches at the proxy or client ends in order to reduce the latency. In this
paper, we consider a novel caching framework with erasure code called
functional caching. Functional Caching involves using erasure-coded chunks in
the cache such that the code formed by the chunks in storage nodes and cache
combined are maximal-distance-separable (MDS) erasure codes. Based on the
arrival rates of different files, placement of file chunks on the servers, and
service time distribution of storage servers, an optimal functional caching
placement and the access probabilities of the file request from different disks
are considered. The proposed algorithm gives significant latency improvement in
both simulations and a prototyped solution in an open-source, cloud storage
deployment.


title:
Cosmological implications of the transition from the false vacuum to the
  true vacuum state

abstract:
  We study the cosmology with the running dark energy. The parametrization of
dark energy with the respect to the redshift is derived from the first
principles of quantum mechanics. Energy density of dark energy is obtained from
the quantum process of transition from the false vacuum state to the true
vacuum state. This is the class of the extended interacting $\Lambda$CDM
models. We consider the energy density of dark energy parametrization
$\rho_\text{de}(t)$, which follows from the Breit-Wigner energy distribution
function which is used to model the quantum unstable systems. The idea that
properties of the process of the quantum mechanical decay of unstable states
can help to understand the properties of the observed universe was formulated
by Krauss and Dent and this idea was used in our considerations. In the
cosmological model with the mentioned parametrization there is an energy
transfer between the dark matter and dark energy. In such a evolutional
scenario the universe is starting from the false vacuum state and going to the
true vacuum state of the present day universe. We find that the intermediate
regime during the passage from false to true vacuum states takes place. The
intensity of the analyzed process is measured by a parameter $\alpha$. For the
small value of $\alpha$ ($0<\alpha <0.4$) this intermediate (quantum) regime is
characterized by an oscillatory behavior of the density of dark energy while
the for $\alpha > 0.4$ the density of the dark energy simply jumps down. In
both cases (independent from the parameter $\alpha$) the today value of density
of dark energy is reached at the value of $0.7$. We estimate the cosmological
parameters for this model with visible and dark matter. This model becomes in
good agreement with the astronomical data and is practically indistinguishable
from $\Lambda$CDM model.


title: Time-period flow of a viscous liquid past a body

abstract:
  Time-periodic solutions to the Navier-Stokes equations that govern the flow
of a viscous liquid past a three-dimensional body moving with a time-periodic
velocity are investigated. The net motion of the body over a full time-period
is assumed to be non-zero. In this case the appropriate linearization of the
system is constituted by the time-periodic Oseen equations in a
three-dimensional exterior domain. A priori Lp estimates are established for
this linearization. Based on these estimates, existence of a solution to the
fully non-linear Navier-Stokes problem is obtained by the contraction mapping
principle.


title:
Meta-Analytics: Tools for Understanding the Statistical Properties of
  Sports Metrics

abstract:
  In sports, there is a constant effort to improve metrics which assess player
ability, but there has been almost no effort to quantify and compare existing
metrics. Any individual making a management, coaching, or gambling decision is
quickly overwhelmed with hundreds of statistics. We address this problem by
proposing a set of "meta-metrics" which can be used to identify the metrics
that provide the most unique, reliable, and useful information for
decision-makers. Specifically, we develop methods to evalute metrics based on
three criteria: 1) stability: does the metric measure the same thing over time
2) discrimination: does the metric differentiate between players and 3)
independence: does the metric provide new information? Our methods are easy to
implement and widely applicable so they should be of interest to the broader
sports community. We demonstrate our methods in analyses of both NBA and NHL
metrics. Our results indicate the most reliable metrics and highlight how they
should be used by sports analysts. The meta-metrics also provide useful
insights about how to best construct new metrics which provide independent and
reliable information about athletes.


title:
On entropy change measurements around first order phase transitions in
  caloric materials

abstract:
  In this work we discuss the measurement protocols for indirect determination
of the isothermal entropy change associated with first order phase transitions
in caloric materials. The magneto- structural phase transitions giving rise to
giant magnetocaloric effects in Cu-doped MnAs and FeRh are used as case studies
to exemplify how badly designed protocols may affect isothermal measure- ments
and lead to incorrect entropy change estimations. Isothermal measurement
protocols which allow correct assessment of the entropy change around first
order phase transitions in both direct and inverse cases are presented.


title:
How beaming of gravitational waves compares to the beaming of
  electromagnetic waves: impacts to gravitational wave detection

abstract:
  We focus on understanding the beaming of gravitational radiation from gamma
ray bursts (GRBs) by approximating GRBs as linearly accelerated point masses.
For accelerated point masses, it is known that gravitational radiation is
beamed isotropicly at high speeds, and beamed along the polar axis at low
speeds. Aside from this knowledge, there has been very little work done on
beaming of gravitational radiation from GRBs, and the impact beaming could have
on gravitational wave (GW) detection. We determine the following: (1) the
observation angle at which the most power is emitted as a function of speed,
(2) the maximum ratio of power radiated away as a function of speed, and (3)
the angular distribution of power ratios at relativistic and non-relativistic
speeds. Additionally the dependence of the beaming of GW radiation on speed is
essentially the opposite of the beaming of electromagnetic (EM) radiation from
GRBs. So we investigate why this is the case by calculating the angular EM
radiation distribution from a linear electric quadrupole, and compare this
distribution to the angular gravitational radiation distribution from a GRB.


title:
A fast, open source implementation of adaptive biasing potentials
  uncovers a ligand design strategy for the chromatin regulator BRD4

abstract:
  In this communication we introduce an efficient implementation of adaptive
biasing that greatly improves the speed of free energy computation in molecular
dynamics simulations. We investigated the use of accelerated simulations to
inform on compound design using a recently reported and clinically relevant
inhibitor of the chromatin regulator BRD4. Benchmarking on our local compute
cluster, our implementation achieves up to 2.5 times more force calls per day
than plumed2. Results of five 1{\mu}second-long simulations are presented,
which reveal a conformational switch in the BRD4 inhibitor between a binding
competent and incompetent state. Stabilization of the switch led to a -3
kcal/mol improvement of absolute binding free energy. These studies suggest an
unexplored ligand design principle and offer new actionable hypotheses for
medicinal chemistry efforts against this druggable epigenetic target class.


title: Integrable deformations of T-dual $\sigma$ models

abstract:
  We present a method to deform (generically non-abelian) T duals of
two-dimensional $\sigma$ models, which preserves classical integrability. The
deformed models are identified by a linear operator $\omega$ on the dualised
subalgebra, which satisfies the 2-cocycle condition. We prove that the
so-called homogeneous Yang-Baxter deformations are equivalent, via a field
redefinition, to our deformed models when $\omega$ is invertible. We explain
the details for deformations of T duals of Principal Chiral Models, and present
the corresponding generalisation to the case of supercoset models.


title: Extremal Density Matrices for Qudit States

abstract:
  An algebraic procedure to find extremal density matrices for any Hamiltonian
of a qudit system is established. The extremal density matrices for pure states
provide a complete description of the system, that is, the energy spectra of
the Hamiltonian and their corresponding projectors. For extremal density
matrices representing mixed states, one gets mean values of the energy in
between the maximum and minimum energies associated to the pure case. These
extremal densities give also the corresponding mixture of eigenstates that
yields the corresponding mean value of the energy. We enhance that the method
can be extended to any hermitian operator.


title: Optimal line packings from nonabelian groups

abstract:
  We use group schemes to construct optimal packings of lines through the
origin. In this setting, optimal line packings are naturally characterized
using representation theory, which in turn leads to a necessary integrality
condition for the existence of equiangular central group frames. We conclude
with an infinite family of optimal line packings using the group schemes
associated with certain Suzuki 2-groups, specifically, extensions of Heisenberg
groups. Notably, this is the first known infinite family of equiangular tight
frames generated by representations of nonabelian groups.


title: A Sharp Threshold for Spanning 2-Spheres in Random 2-Complexes

abstract:
  A Hamiltonian cycle in a graph is a spanning subgraph that is homeomorphic to
a circle. With this in mind, it is natural to define a Hamiltonian d-sphere in
a d-dimensional simplicial complex as a spanning subcomplex that is
homeomorphic to a d-dimensional sphere.
  We consider the Linial-Meshulam model for random simplicial complexes, and
prove that there is a sharp threshold at $p=\sqrt{\frac{e}{\gamma n}}$ for the
appearance of a Hamiltonian $2$-sphere in a random $2$-complex, where $\gamma =
4^4/3^3$.


title:
Realization of Gain with Electromagnetically Induced Transparency System
  with Non-degenerate Zeeman Sublevels in $^{87}$Rb

abstract:
  Previously, we had proposed an optically-pumped five-level Gain EIT (GEIT)
system, which has a transparency dip superimposed on a gain profile and
exhibits a negative dispersion suitable for the white-light-cavity
signal-recycling (WLC-SR) scheme of the interferometeric gravitational wave
detector [Phys. Rev. D. 92, 082002 (2015)]. Using this system as the negative
dispersion medium (NDM) in the WLC-SR, we get an enhancement in the quantum
noise (QN) limited sensitivity-bandwidth product by a factor of ~18. Here, we
show how to realize this GEIT system in a realistic platform, using
non-degenerate Zeeman sublevels in alkali atoms. Specifically we choose
$^{87}$Rb atoms, which produce the negative dispersion around 795nm. The
current LIGO operates at 1064nm but future LIGO may operate at a wavelength
that is consistent with this atomic system. We present a theoretical analysis
for the susceptibilities of the system. To account for the QN from the GEIT
system, it is necessary to use the master equation (ME) approach. However, due
to the number of energy levels involved, applying the full ME approach to this
system is very complex. We have also shown earlier, in the reference cited
above, that under GEIT condition, the net enhancement in the
sensitivity-bandwidth product, as predicted by the ME, is close to that
predicted by applying the Caves model for a phase-insensitive linear amplifier.
Therefore we here use the Caves model for the QN from the NDM and this
simplified numerical model shows that the enhancement of the
sensitivity-bandwidth product as high as 17 is possible.

categories: physics.ins-det gr-qc physics.atom-ph quant-ph


title: Depleted Depletion Drives Polymer Swelling in Poor Solvent Mixtures

abstract:
  Macromolecular solubility in solvent mixtures often exhibit striking and
paradoxical nature. For example, when two well miscible poor solvents for a
given polymer are mixed together, the same polymer may swell within
intermediate mixing ratios. We combine computer simulations and theoretical
arguments to unveil the first microscopic, generic origin of this
collapse-swelling-collapse scenario. We show that this phenomenon naturally
emerges at constant pressure in mixtures of purely repulsive components,
especially when a delicate balance of the entropically driven depletion
interactions is achieved.


title: Regular and almost universal hashing: an efficient implementation

abstract:
  Random hashing can provide guarantees regarding the performance of data
structures such as hash tables---even in an adversarial setting. Many existing
families of hash functions are universal: given two data objects, the
probability that they have the same hash value is low given that we pick hash
functions at random. However, universality fails to ensure that all hash
functions are well behaved. We further require regularity: when picking data
objects at random they should have a low probability of having the same hash
value, for any fixed hash function. We present the efficient implementation of
a family of non-cryptographic hash functions (PM+) offering good running times,
good memory usage as well as distinguishing theoretical guarantees: almost
universality and component-wise regularity. On a variety of platforms, our
implementations are comparable to the state of the art in performance. On
recent Intel processors, PM+ achieves a speed of 4.7 bytes per cycle for 32-bit
outputs and 3.3 bytes per cycle for 64-bit outputs. We review vectorization
through SIMD instructions (e.g., AVX2) and optimizations for superscalar
execution.


title:
GPU Acceleration of Hermite Methods for the Simulation of Wave
  Propagation

abstract:
  The Hermite methods of Goodrich, Hagstrom, and Lorenz (2006) use Hermite
interpolation to construct high order numerical methods for hyperbolic initial
value problems. The structure of the method has several favorable features for
parallel computing. In this work, we propose algorithms that take advantage of
the many-core architecture of Graphics Processing Units. The algorithm exploits
the compact stencil of Hermite methods and uses data structures that allow for
efficient data load and stores. Additionally the highly localized evolution
operator of Hermite methods allows us to combine multi-stage time-stepping
methods within the new algorithms incurring minimal accesses of global memory.
Using a scalar linear wave equation, we study the algorithm by considering
Hermite interpolation and evolution as individual kernels and alternatively
combined them into a monolithic kernel. For both approaches we demonstrate
strategies to increase performance. Our numerical experiments show that
although a two kernel approach allows for better performance on the hardware, a
monolithic kernel can offer a comparable time to solution with less global
memory usage.


title:
Algebraic functions with Fermat property, eigenvalues of transfer
  operator and Riemann zeros, and other open problems

abstract:
  In this note we list a number of open problems in the fields of number
theory, combinatorics, and representation theory: algebraic functions with
Fermat property; power product expansion of the generating function for the
partition function; relation between the non-trivial Riemann zeros and
eigenvalues of the transfer operator; functional equation related to norm
forms; two problems from geometric combinatorics; a problem on the moments of
the Minkowski question mark function; a question in representation theory; a
problem on interpolating the moments of the Stern's diatomic sequence; an
arithmetic properties of the binary composition function.


title: Boundary interpolation by finite Blaschke products

abstract:
  Given $n$ distinct points $t_1,\ldots,t_n$ on the unit circle $\T$ and
equally many target values $\f_1,\ldots,\f_n\in\T$, we describe all Blaschke
products $f$ of degree at most $n-1$ such that $f(t_i)=\f_i$ for
$i=1,\ldots,n$. We also describe the cases where degree $n-1$ is the minimal
possible.


title: Staggered quantum walks with superconducting microwave resonators

abstract:
  The staggered quantum walk model on a graph is defined by an evolution
operator that is the product of local operators related to two or more
independent graph tessellations. A graph tessellation is a partition of the set
of nodes that respects the neighborhood relation. Flip-flop coined quantum
walks with the Hadamard or Grover coins can be expressed as staggered quantum
walks by converting the coin degree of freedom into extra nodes in the graph.
We propose an implementation of the staggered model with superconducting
microwave resonators, where the required local operations are provided by the
nearest neighbor interaction of the resonators coupled through superconducting
quantum interference devices. The tunability of the interactions makes this
system an excellent toolbox for this class of quantum walks. We focus on the
one-dimensional case and discuss its generalization to a more general class
known as triangle-free graphs.


title:
The Tricritical Point of the f-electron Antiferromagnet USb2 Driven by
  High Magnetic Fields

abstract:
  In pulsed magnetic fields up to 65T and at temperatures below the N\'eel
transition, our magnetization and magnetostriction measurements reveal a
field-induced metamagnetic-like transition that is suggestive of an
antiferromagnetic to polarized paramagnetic or ferrimagnetic ordering. Our data
also suggests a change in the nature of this metamagnetic-like transition from
second- to first-order-like near a tricritical point at T_{tc} ~145K and
H_{c}~52T. At high fields for H>H_{c} we found a decreased magnetic moment
roughly half of the moment reported in low field measurements. We propose that
\mathit{f-p} hybridization effects and magnetoelastic interactions drive the
decreased moment, lack of saturation at high fields, and the decreased phase
boundary.


title: Ultra-stable 2D/3D hybrid perovskite photovoltaic module

abstract:
  Hybrid perovskite solar cells, with their power conversion efficiency (PCE)
exceeding 22%, have been representing a revolutionary concept for future energy
power generation. Although listed among the Top 10 Emerging Technologies of
2016, device longevity is the actual bottleneck for their real uptake in the
market. Here we design an ultra-stable molecular junction of two/three
dimensional (2D/3D) perovskites. It consists of a 2D (HOOC(CH2)2NH3)2PbI4,
anchored at the oxide substrate, that templates the growth of a highly ordered
3D CH3NH3PbI3 perovskite stabilizing in the orthorhombic phase, even at room
temperature. The unique and exceptional 2D/3D structure yields 14.6% PCE in
solar cells with Spiro-OMeTAD and Au, and 12.9% PCE in hole-conductor free
architecture. Aiming at the up-scaling of this technology, we realize 10x10 cm2
large-area photovoltaic modules by a low-cost, fully printable,
industrial-scale process delivering 11.2% PCE. We demonstrate a record
stability in the PCE of 5,000 hours, setting the direction for the new
generation of carbon free energy.


title:
Solution of Cavity Resonance and Waveguide Scattering Problems Using the
  Eigenmode Projection Technique

abstract:
  An eigenmode projection technique (EPT) is developed and employed to solve
problems of electromagnetic resonance in closed cavities and scattering from
discontinuities in guided-wave structures. The EPT invokes the eigenmodes of a
canonical predefined cavity in the solution procedure and uses the expansion of
these eigenmodes to solve Maxwell's equations, in conjunction with a convenient
choice of port boundary conditions. For closed cavities, resonance frequencies
of arbitrary-shaped cavities are accurately determined with a robust and
efficient separation method of spurious modes. For waveguide scattering
problems, the EPT is combined with the generalized scattering matrix approach
to solve problems involving waveguide discontinuities with arbitrary dielectric
profiles. Convergence studies show stable solutions for a relatively small
number of expansion modes, and the proposed method shows great robustness over
conventional solvers in analyzing electromagnetic problems with inhomogeneous
materials.


title: How to Measure Squeeze Out

abstract:
  Squeeze out happen when the expanding central fireball flows around a large
surface flux tube in a central Au-Au collision at RHIC. We model such an effect
in a flux tube model. Two particle correlations with respect to the $v_2$ axis
formed by the soft fireball particles flowing around this large flux tube is a
way of measuring the effect.


title: Lepton-Flavored Electroweak Baryogenesis

abstract:
  We explore lepton-flavored electroweak baryogenesis, driven by CP-violation
in leptonic Yukawa sector, using the $\tau-\mu$ system in the two Higgs doublet
model as an example. This setup generically yields, together with the
flavor-changing decay $h\to \tau \mu$, a tree-level Jarlskog-invariant that can
drive dynamical generation of baryon asymmetry during a first-order electroweak
phase transition and results in CP-violating effect in the decay $h\to
\tau\tau$. We find that the observed baryon asymmetry can be generated in
parameter space compatible with current experimental results for the decays
$h\to \tau \mu$, $h\to \tau\tau$ and $\tau \rightarrow \mu \gamma$, as well as
the present bound on the electric dipole moment of the electron. The baryon
asymmetry generated is intrinsically correlated with the CP-violating decay
$h\to \tau\tau$ and the flavor-changing decay $h\to \tau\mu$, which thus may
serve as "smoking guns" to test lepton-flavored electroweak baryogenesis.


title: Latent fingerprint minutia extraction using fully convolutional network

abstract:
  Minutiae play a major role in fingerprint identification. Extracting reliable
minutiae is difficult for latent fingerprints which are usually of poor
quality. As the limitation of traditional handcrafted features, a fully
convolutional network (FCN) is utilized to learn features directly from data to
overcome complex background noises. Raw fingerprints are mapped to a
correspondingly-sized minutia-score map with a fixed stride. And thus a large
number of minutiae will be extracted through a given threshold. Then small
regions centering at these minutia points are entered into a convolutional
neural network (CNN) to reclassify these minutiae and calculate their
orientations. The CNN shares convolutional layers with the fully convolutional
network to speed up. 0.45 second is used on average to detect one fingerprint
on a GPU. On the NIST SD27 database, we achieve 53\% recall rate and 53\%
precise rate that outperform many other algorithms. Our trained model is also
visualized to show that we have successfully extracted features preserving
ridge information of a latent fingerprint.


title: Conformal transforms and Doob's h-processes on Heisenberg groups

abstract:
  We study the stochastic processes that are images of Brownian motions on
Heisenberg group H2n+1 under conformal maps. In particular, we obtain that
Cayley transform maps Brownian paths in H2n+1 to a time changed Brownian motion
on CR sphere S2n+1 conditioned to be at its south pole at a random time. We
also obtain that the inversion of Brownian motion on H2n+1 started from x\not=
0, is up to time change, a Brownian bridge on H2n+1 conditioned to be at the
origin.


title: Multi-level perspective on high-order harmonic generation in solids

abstract:
  We investigate high-order harmonic generation in a solid, modeled as a
multi-level system dressed by a strong infrared laser field. We show that the
cutoff energies and the relative strengths of the multiple plateaus that emerge
in the harmonic spectrum can be understood both qualitatively and
quantitatively by considering a combination of adiabatic and diabatic processes
driven by the strong field. Such a model was recently used to interpret the
multiple plateaus exhibited in harmonic spectra generated by solid argon and
krypton [Ndabashimiye {\it et al.}, Nature 534, 520 (2016)]. We also show that
when the multi-level system originates from the Bloch state at the $\Gamma$
point of the band structure, the laser-dressed states are equivalent to the
Houston states [Krieger {\it el al.} Phys. Rev. B 33, 5494 (1986)] and will
therefore map out the band structure away from the $\Gamma$ point as the laser
field increases. This leads to a semi-classical three-step picture in momentum
space that describes the high-order harmonic generation process in a solid.


title: Origin of the effective mobility in non-linear active micro-rheology

abstract:
  The distinction between the damping coefficient and the effective non-linear
mobility of driven particles in active micro-rheology of supercooled liquids is
explained in terms of individual and collective dynamics. The effective
mobility arises as a collective effect which gives insight into the energy
landscape of the system. On the other hand, the damping coefficient is a
constant that modulates the effect of external forces over the thermal energy
which particles have at their disposition to perform Brownian motion. For long
times, these thermal fluctuations become characterized in terms of an effective
temperature that is a consequence of the dynamic coupling between kinetic and
configurational degrees of freedom induced by the presence of the strong
external force. The interplay between collective mobility and effective
temperature allows to formulate a generalized Stokes-Einstein relation that may
be used to determine the collective diffusion coefficient. The explicit
relations we deduce reproduce simulation data remarkably well.