title:
Spherically symmetric sector of self dual Ashtekar gravity coupled to
  matter: Anomaly-free algebra of constraints with holonomy corrections

abstract:
  Using self dual Ashtekar variables, we investigate (at the effective level)
the spherically symmetry reduced model of loop quantum gravity, both in vacuum
and when coupled to a scalar field. Within the real Ashtekar-Barbero
formulation, the system scalar field coupled to spherically symmetric gravity
is known to possess a non closed (quantum) algebra of constraints once the
holonomy corrections are introduced, which forbids the loop quantization of the
model. Moreover, the vacuum case, while not anomalous, introduces modifications
which are usually interpreted as an effective signature change of the metric in
the deep quantum region. We show in this paper that both those complications
disappear when working with self dual Ashtekar variables, both in the vacuum
case and in the case of gravity minimally coupled to a scalar field. In this
framework, the algebra of the holonomy corrected constraints is anomaly free
and reproduces the classical hypersurface deformation algebra without any
deformations. A possible path towards quantization of this model is briefly
discussed.


title: Full Rotational Control of Levitated Silicon Nanorods

abstract:
  We study a nanofabricated silicon rod levitated in an optical trap. By
manipulating the polarization of the light we gain full control over the
ro-translational dynamics of the rod. We are able to trap both its
centre-of-mass and align it along the linear polarization of the laser field.
The rod can be set into rotation at a tuned frequency by exploiting the
radiation pressure exerted by elliptically polarized light. The rotational
motion of the rod dynamically modifies the optical potential, which allows
tuning of the rotational frequency over hundreds of Kilohertz. This ability to
trap and control the motion and alignment of nanoparticles opens up the field
of rotational optomechanics, rotational ground state cooling and the study of
rotational thermodynamics in the underdamped regime.


title:
Spectrally engineered broadband photon source for two-photon quantum
  interferometry

abstract:
  We present a new approach to engineering broadband sources of entangled
photon pairs for quantum interferometry. The source is based on
quasi-phase-matched spontaneous parametric down conversion in a titanium
diffused periodically poled lithium niobate waveguide with a strongly-chirped
poling period. The proposed non-standard asymmetric poling mitigates phase
distortions associated with the process of chirping. Asymmetric poling
significantly broadens the entangled source bandwidth while preserving high
visibility quantum interferometric sensing.


title: On the Distribution of Witnesses in the Miller-Rabin Test

abstract:
  We show that the set of normalized Miller-Rabin witnesses becomes
equidistributed in the unit interval. This will be done by exhibiting
cancellation in certain exponential sums.


title:
Massively parallel dual-comb molecular detection with subharmonic
  optical parametric oscillators

abstract:
  Mid-infrared (mid-IR) spectroscopy offers unparalleled sensitivity for the
detection of trace gases, solids and liquids, which is based on the existence
of strong telltale vibrational bands in this part of the spectrum. It was shown
more than a decade ago that a dual-comb Fourier spectroscopy could provide
superior spectral coverage combined with high resolution and extremely fast
data acquisition. Capabilities of this method were limited because of
difficulty of producing twins of mutually coherent frequency combs in the mid-
IR. Here we report a phase-coherent and broadband dual-comb system that is
based on a pair of subharmonic (frequency-divide-by-two) optical parametric
oscillators, pumped in turn by two phase-locked thulium fiber lasers at
2-micron wavelength. We demonstrate simultaneous detection of multiple
molecular species in the whole band of 3.2-5.3 microns (frequency span 1200
cm^{-1}) augmented by the pump laser band of 1.85-2 microns (span 400 cm^{-1}),
with spectral resolution 0.01-0.07 cm^{-1} and acquisition speed of up to
160,000 resolution elements in few seconds.


title: A Euclidean bridge to the relativistic constituent quark model

abstract:
  ${\bf Background}$ Knowledge of nucleon structure is today ever more of a
precision science, with heightened theoretical and experimental activity
expected in coming years. At the same time, a persistent gap lingers between
theoretical approaches grounded in Euclidean methods (e.g., lattice QCD,
Dyson-Schwinger Equations [DSEs]) as opposed to traditional Minkowski field
theories (such as light-front constituent quark models). ${\bf Purpose}$
Seeking to bridge these complementary worldviews, we explore the potential of a
Euclidean constituent quark model (ECQM). This formalism enables us to study
the gluonic dressing of the quark-level axial-vector vertex, which we undertake
as a test of the framework. ${\bf Method}$ To access its indispensable elements
with a minimum of inessential detail, we develop our ECQM using the simplified
quark $+$ scalar diquark picture of the nucleon. We construct a hyperspherical
formalism involving polynomial expansions of diquark propagators to marry our
ECQM with the results of Bethe-Salpeter Equation (BSE) analyses, and constrain
model parameters by fitting electromagnetic form factor data. ${\bf Results}$
From this formalism, we define and compute a new quantity --- the Euclidean
density function (EDF) --- an object that characterizes the nucleon's various
charge distributions as functions of the quark's Euclidean momentum. Applying
this technology and incorporating information from BSE analyses, we find the
dressing effect on the proton's axial-singlet charge to be small in magnitude
and consistent with zero. ${\bf Conclusions}$ The scalar quark $+$ diquark ECQM
is a step toward a realistic quark model in Euclidean space, and urges
additional refinements. The small size we obtain for the impact of the dressed
vertex on the axial-singlet charge suggests that models without this effect are
on firm ground to neglect it.


title:
Inapplicability of exact constraints and a minimal two-parameter
  generalization to the DFT+$U$ based correction of self-interaction error

abstract:
  In approximate density functional theory (DFT), the self-interaction error is
an electron delocalization anomaly associated with underestimated insulating
gaps. It exhibits a predominantly quadratic energy-density curve that is
amenable to correction using efficient, constraint-resembling methods such as
DFT + Hubbard $U$ (DFT+$U$). Constrained DFT (cDFT) enforces conditions on DFT
exactly, by means of self-consistently optimized Lagrange multipliers, and
while its use to automate error corrections is a compelling possibility, we
show that it is limited by a fundamental incompatibility with constraints
beyond linear order. We circumvent this problem by utilizing separate linear
and quadratic correction terms, which may be interpreted either as distinct
constraints, each with its own Hubbard $U$ type Lagrange multiplier, or as the
components of a generalized DFT+$U$ functional. The latter approach prevails in
our tests on a model one-electron system, $H_2^+$, in that it readily recovers
the exact total-energy while symmetry-preserving pure constraints fail to do
so. The generalized DFT+$U$ functional moreover enables the simultaneous
correction of the total-energy and ionization potential or the correction of
either together with the enforcement of Koopmans condition. For the latter
case, we outline a practical, approximate scheme by which the required pair of
Hubbard parameters, denoted as U1 and U2, may be calculated from
first-principles.

categories: physics.chem-ph cond-mat.str-el physics.comp-ph quant-ph


title: Direct Frequency Comb Measurement of OD + CO -> DOCO Kinetics

abstract:
  The kinetics of the OH + CO reaction, fundamental to both atmospheric and
combustion chemistry, are complex due to the formation of the HOCO
intermediate. Despite extensive studies on this reaction, HOCO has not been
observed at thermal reaction conditions. Exploiting the sensitive, broadband,
and high-resolution capabilities of time-resolved cavity-enhanced direct
frequency comb spectroscopy, we observe OD + CO reaction kinetics with the
detection of stabilized trans-DOCO, the deuterated analogue of trans-HOCO, and
its yield. By simultaneously measuring the time-dependent concentrations of
both trans-DOCO and OD species, we observe unambiguous low-pressure
termolecular dependence on the reaction rate coefficients for both N2 and CO
bath gases. These results confirm the HOCO formation mechanism and quantify its
yield.


title: Stellar magnetic cycles in the solar-like stars Kepler-17 and Kepler-63

abstract:
  The stellar magnetic field plays a crucial role in the star internal
mechanisms, as in the interactions with its environment. The study of starspots
provides information about the stellar magnetic field, and can characterise the
cycle. Moreover, the analysis of solar-type stars is also useful to shed light
onto the origin of the solar magnetic field. The objective of this work is to
characterise the magnetic activity of stars. Here, we studied two solar-type
stars Kepler-17 and Kepler-63 using two methods to estimate the magnetic cycle
length. The first one characterises the spots (radius, intensity, and location)
by fitting the small variations in the light curve of a star caused by the
occultation of a spot during a planetary transit. This approach yields the
number of spots present in the stellar surface and the flux deficit subtracted
from the star by their presence during each transit. The second method
estimates the activity from the excess in the residuals of the transit
lightcurves. This excess is obtained by subtracting a spotless model transit
from the lightcurve, and then integrating all the residuals during the transit.
The presence of long term periodicity is estimated in both time series. With
the first method, we obtained $P_{\rm cycle}$ = 1.12 $\pm$ 0.16 yr (Kepler-17)
and $P_{\rm cycle}$ = 1.27 $\pm$ 0.16 yr (Kepler-63), and for the second
approach the values are 1.35 $\pm$ 0.27 yr and 1.27 $\pm$ 0.12 yr,
respectively. The results of both methods agree with each other and confirm
their robustness.


title:
Comparing Speech and Keyboard Text Entry for Short Messages in Two
  Languages on Touchscreen Phones

abstract:
  With the ubiquity of mobile touchscreen devices like smartphones, two widely
used text entry methods have emerged: small touch-based keyboards and speech
recognition. Although speech recognition has been available on desktop
computers for years, it has continued to improve at a rapid pace, and it is
currently unknown how today's modern speech recognizers compare to
state-of-the-art mobile touch keyboards, which also have improved considerably
since their inception. To discover both methods' "upper-bound performance," we
evaluated them in English and Mandarin Chinese on an Apple iPhone 6 Plus in a
laboratory setting. Our experiment was carried out using Baidu's Deep Speech 2,
a deep learning-based speech recognition system, and the built-in Qwerty
(English) or Pinyin (Mandarin) Apple iOS keyboards. We found that with speech
recognition, the English input rate was 2.93 times faster (153 vs. 52 WPM), and
the Mandarin Chinese input rate was 2.87 times faster (123 vs. 43 WPM) than the
keyboard for short message transcription under laboratory conditions for both
methods. Furthermore, although speech made fewer errors during entry (5.30% vs.
11.22% corrected error rate), it left slightly more errors in the final
transcribed text (1.30% vs. 0.79% uncorrected error rate). Our results show
that comparatively, under ideal conditions for both methods, upper-bound speech
recognition performance has greatly improved compared to prior systems, and
might see greater uptake in the future, although further study is required to
quantify performance in non-laboratory settings for both methods.


title: Nonreciprocal Nongyrotropic Magnetless Metasurface

abstract:
  We introduce a nonreciprocal nongyrotropic magnetless metasurface. In
contrast to previous nonreciprocal structures, this metasurface does not
require a biasing magnet, and is therefore lightweight and amenable to
integrated circuit fabrication. Moreover, it does not induce Faraday rotation,
and hence does not alter the polarization of waves, which is a desirable
feature in many nonreciprocal devices. The metasurface is designed according to
a Surface-Circuit-Surface (SCS) architecture and leverages the inherent
unidirectionality of transistors for breaking time reversal symmetry.
Interesting features include transmission gain as well as broad operating
bandwidth and angular sector operation. It is finally shown that the
metasurface is bianisotropic in nature, with nonreciprocity due to the
electric-magnetic coupling parameters, and structurally equivalent to a moving
uniaxial metasurface.


title:
From clocks to cloners: Catalytic transformations under covariant
  operations and recoverability

abstract:
  There are various physical scenarios in which one can only implement
operations with a certain symmetry. Under such restriction, a system in a
symmetry-breaking state can be used as a catalyst, e.g. to prepare another
system in a desired symmetry-breaking state. This sort of (approximate)
catalytic state transformations are relevant in the context of (i) state
preparation using a bounded-size quantum clock or reference frame, where the
clock or reference frame acts as a catalyst, (ii) quantum thermodynamics, where
again a clock can be used as a catalyst to prepare states which contain
coherence with respect to the system Hamiltonian, and (iii) cloning of unknown
quantum states, where the given copies of state can be interpreted as a
catalyst for preparing the new copies. Using a recent result of Fawzi and
Renner on approximate recoverability, we show that the achievable accuracy in
this kind of catalytic transformations can be determined by a single function,
namely the relative entropy of asymmetry, which is equal to the difference
between the entropy of state and its symmetrized version: if the desired state
transition does not require a large increase of this quantity, then it can be
implemented with high fidelity using only symmetric operations. Our lower bound
on the achievable fidelity is tight in the case of cloners, and can be achieved
using the Petz recovery map, which interestingly turns out to be the optimal
cloning map found by Werner.


title:
Two-Photon Absorption Spectroscopy using Intense Phase-Chirped Entangled
  Beams

abstract:
  We numerically analyze the use of intense entangled twin beams for
ultra-sensitive spectroscopic measurements in chemical and biological systems.
The examined scheme makes use of intense frequency-modulated (chirped)
entangled beams to successfully extract information about the intermediate
material states that contribute to the two-photon excitation of an absorbing
medium. Robustness of the presented method is examined with respect to the
applied intervals of the frequency chirp.


title: SIS Epidemic Spreading with Correlated Heterogeneous Infection Rates

abstract:
  The epidemic spreading has been widely studied when each node may get
infected by an infected neighbor with the same rate. However, the infection
rate between a pair of nodes is usually heterogeneous and even correlated with
their nodal degrees in the contact network. We aim to understand how such
correlated heterogeneous infection rates influence the spreading on different
network topologies. Motivated by real-world datasets, we propose a correlated
heterogeneous Susceptible-Infected-Susceptible model which assumes that the
infection rate $\beta_{ij}(=\beta_{ji})$ between node $i$ and $j$ is correlated
with the degree of the two end nodes: $\beta_{ij}=c(d_id_j)^\alpha$, where
$\alpha$ indicates the strength of the correlation and $c$ is selected so that
the average infection rate is $1$. In order to understand the effect of such
correlation on epidemic spreading, we consider as well the corresponding
uncorrected but still heterogeneous infection rate scenario as a reference,
where the original correlated infection rates in our CSIS model are shuffled
and reallocated to the links of the same network topology. We compare these two
scenarios in the average fraction of infected nodes in the metastable state on
Erd{\"o}s-R{\'e}nyi (ER) and scale-free (SF) networks with a similar average
degree. Through the continuous-time simulations, we find that, when the
recovery rate is small, the negative correlation is more likely to help the
epidemic spread and the positive correlation prohibit the spreading; as the
recovery rate increases to be larger than a critical value, the positive but
not negative correlation tends to help the spreading. Our findings are further
analytically proved in a wheel network (one central node connects with each of
the nodes in a ring) and validated on real-world networks with correlated
heterogeneous interaction frequencies.


title: Fundamental Limits of Budget-Fidelity Trade-off in Label Crowdsourcing

abstract:
  Digital crowdsourcing (CS) is a modern approach to perform certain large
projects using small contributions of a large crowd. In CS, a taskmaster
typically breaks down the project into small batches of tasks and assigns them
to so-called workers with imperfect skill levels. The crowdsourcer then
collects and analyzes the results for inference and serving the purpose of the
project. In this work, the CS problem, as a human-in-the-loop computation
problem, is modeled and analyzed in an information theoretic rate-distortion
framework. The purpose is to identify the ultimate fidelity that one can
achieve by any form of query from the crowd and any decoding (inference)
algorithm with a given budget. The results are established by a joint source
channel (de)coding scheme, which represent the query scheme and inference, over
parallel noisy channels, which model workers with imperfect skill levels. We
also present and analyze a query scheme dubbed $k$-ary incidence coding and
study optimized query pricing in this setting.


title:
Scheduling Resource-Bounded Monitoring Devices for Event Detection and
  Isolation in Networks

abstract:
  In networked systems, monitoring devices such as sensors are typically
deployed to monitor various target locations. Targets are the points in the
physical space at which events of some interest, such as random faults or
attacks, can occur. Most often, these devices have limited energy supplies, and
they can operate for a limited duration. As a result, energy-efficient
monitoring of various target locations through a set of monitoring devices with
limited energy supplies is a crucial problem in networked systems. In this
paper, we study optimal scheduling of monitoring devices to maximize network
coverage for detecting and isolating events on targets for a given network
lifetime. The monitoring devices considered could remain active only for a
fraction of the overall network lifetime. We formulate the problem of
scheduling of monitoring devices as a graph labeling problem, which unlike
other existing solutions, allows us to directly utilize the underlying network
structure to explore the trade-off between coverage and network lifetime. In
this direction, first we propose a greedy heuristic to solve the graph labeling
problem, and then provide a game-theoretic solution to achieve near optimal
graph labeling. Moreover, the proposed setup can be used to simultaneously
solve the scheduling and placement of monitoring devices, which yields improved
performance as compared to separately solving the placement and scheduling
problems. Finally, we illustrate our results on various networks, including
real-world water distribution networks.


title:
Bayesian Projection of Life Expectancy Accounting for the HIV/AIDS
  Epidemic

abstract:
  While probabilistic projection methods for projecting life expectancy exist,
few account for covariates related to life expectancy. Generalized HIV/AIDS
epidemics have a large, immediate negative impact on the life expectancy in a
country, but this impact can be mitigated by widespread use of antiretroviral
therapy (ART). Thus projection methods for countries with generalized HIV/AIDS
epidemics could be improved by accounting for HIV prevalence, the future course
of the epidemic and coverage of ART. We propose a method for making
probabilistic projections of life expectancy to 2100 for all countries in the
world accounting for HIV prevalence, the future course of the epidemic and its
uncertainty, and adult ART coverage. We extend the current Bayesian
probabilistic life expectancy projection methods of Raftery et al. (2013) to
account for HIV prevalence and adult ART coverage. We evaluate our method using
out-of-sample validation. We find that the proposed method performs better than
the method that does not account for HIV prevalence or ART coverage for
projections of life expectancy in countries with a generalized epidemic, while
projections for countries without an epidemic remain essentially unchanged.


title:
Chiral twist drives raft formation and organization in membranes
  composed of rod-like particles

abstract:
  Lipid rafts are hypothesized to facilitate protein interaction, tension
regulation, and trafficking in biological membranes, but the mechanisms
responsible for their formation and maintenance are not clear. Insights into
many other condensed matter phenomena have come from colloidal systems, whose
micron-scale particles mimic basic properties of atoms and molecules but permit
dynamic visualization with single-particle resolution. Recently, experiments
showed that bidisperse mixtures of filamentous viruses can self-assemble into
colloidal monolayers with thermodynamically stable rafts exhibiting chiral
structure and repulsive interactions. We quantitatively explain these
observations by modeling the membrane particles as chiral liquid crystals.
Chiral twist promotes the formation of finite-sized rafts and mediates a
repulsion that distributes them evenly throughout the membrane. Although this
system is composed of filamentous viruses whose aggregation is entropically
driven by dextran depletants instead of phospholipids and cholesterol with
prominent electrostatic interactions, colloidal and biological membranes share
many of the same physical symmetries. Chiral twist can contribute to the
behavior of both systems and may account for certain stereospecific effects
observed in molecular membranes.


title: Instantons in a Lagrangian model of turbulence

abstract:
  The role of instantons is investigated in the Lagrangian model for the
velocity gradient evolution known as the Recent Fluid Deformation
approximation. After recasting the model into the path-integral formalism, the
probability distribution function is computed along with the most probable path
in the weak noise limit through the saddle-point approximation. Evaluation of
the instanton solution is implemented numerically by means of the iteratively
Chernykh-Stepanov method. In the case of the longitudinal velocity gradient
statistics, due to symmetry reasons, the number of degrees of freedom can be
reduced to one, allowing the pdf to be evaluated analytically as well, thereby
enabling a prediction of the scaling of the moments as a function of Reynolds
number. It is also shown that the instanton solution lies on the Vieillefosse
line concerning the RQ-plane. We illustrate how instantons can be unveiled in
the stochastic dynamics performing a conditional statistics.


title: Angular decomposition of tensor products of a vector

abstract:
  The tensor product of $L$ copies of a single vector, such as $p_{i_1} ...
p_{i_L}$, can be analyzed in terms of angular momentum. When $p_{i_1} ...
p_{i_L}$ is decomposed into a sum of components $( p_{i_1} ... p_{i_L}
)^L_\ell$, each characterized by angular momentum $\ell$, the components are in
general complicated functions of the $p_i$ vectors, especially so for large
$\ell$. We obtain a compact expression for $( p_{i_1} ... p_{i_L} )^L_\ell$
explicitly in terms of the $p_i$ valid for all $L$ and $\ell$. We use this
decomposition to perform three-dimensional Fourier transforms of functions like
$p^n \hat p_{i_1} ... \hat p_{i_L}$ that are useful in describing particle
interactions.


title:
An isoperimetric inequality for the second non-zero eigenvalue of the
  Laplacian on the projective plane

abstract:
  We prove an isoperimetric inequality for the second non-zero eigenvalue of
the Laplace-Beltrami operator on the real projective plane. For a metric of the
unit area this eigenvalue is not greater than 20\pi. This value is attained in
the limit by a sequence of metrics of area one on the projective plane. The
limiting metric is singular and could be realized as a union of the projective
plane and the sphere touching at a point, with standard metrics and the ratio
of the areas 3:2. It is also proven that the multiplicity of the second
non-zero eigenvalue on the projective plane is at most 6.


title: Influence of external potentials on heterogeneous diffusion processes

abstract:
  In this paper we consider heterogeneous diffusion processes with the
power-law dependence of the diffusion coefficient on the position and
investigate the influence of external forces on the resulting anomalous
diffusion. The heterogeneous diffusion processes can yield subdiffusion as well
as superdiffusion, depending on the behavior of the diffusion coefficient. We
assume that not only the diffusion coefficient but also the external force has
a power-law dependence on the position. We obtain analytic expressions for the
transition probability in two cases: when the power-law exponent in the
external force is equal to 2eta-1, where 2eta is the power-law exponent in the
dependence of the diffusion coefficient on the position, and when the external
force has a linear dependence on the position. We found that the power-law
exponent in the dependence of the mean square displacement on time does not
depend on the external force, this force changes only the anomalous diffusion
coefficient. In addition, the external force having the power-law exponent
different from 2eta-1 limits the time interval where the anomalous diffusion
occurs. We expect that the results obtained in this paper may be relevant for a
more complete understanding of anomalous diffusion processes.


title: Playing Anonymous Games using Simple Strategies

abstract:
  We investigate the complexity of computing approximate Nash equilibria in
anonymous games. Our main algorithmic result is the following: For any
$n$-player anonymous game with a bounded number of strategies and any constant
$\delta>0$, an $O(1/n^{1-\delta})$-approximate Nash equilibrium can be computed
in polynomial time. Complementing this positive result, we show that if there
exists any constant $\delta>0$ such that an $O(1/n^{1+\delta})$-approximate
equilibrium can be computed in polynomial time, then there is a fully
polynomial-time approximation scheme for this problem.
  We also present a faster algorithm that, for any $n$-player $k$-strategy
anonymous game, runs in time $\tilde O((n+k) k n^k)$ and computes an $\tilde
O(n^{-1/3} k^{11/3})$-approximate equilibrium. This algorithm follows from the
existence of simple approximate equilibria of anonymous games, where each
player plays one strategy with probability $1-\delta$, for some small $\delta$,
and plays uniformly at random with probability $\delta$.
  Our approach exploits the connection between Nash equilibria in anonymous
games and Poisson multinomial distributions (PMDs). Specifically, we prove a
new probabilistic lemma establishing the following: Two PMDs, with large
variance in each direction, whose first few moments are approximately matching
are close in total variation distance. Our structural result strengthens
previous work by providing a smooth tradeoff between the variance bound and the
number of matching moments.


title: YouSkyde: Information Hiding for Skype Video Traffic

abstract:
  In this paper a new information hiding method for Skype videoconference calls
- YouSkyde - is introduced. A Skype traffic analysis revealed that introducing
intentional losses into the Skype video traffic stream to provide the means for
clandestine communication is the most favourable solution. A YouSkyde
proof-of-concept implementation was carried out and its experimental evaluation
is presented. The results obtained prove that the proposed method is feasible
and offer a steganographic bandwidth as high as 0.93 kbps, while introducing
negligible distortions into transmission quality and providing high
undetectability.


title:
Fast Trajectory Simplification Algorithm for Natural User Interfaces in
  Robot Programming by Demonstration

abstract:
  Trajectory simplification is a problem encountered in areas like Robot
programming by demonstration, CAD/CAM, computer vision, and in GPS-based
applications like traffic analysis. This problem entails reduction of the
points in a given trajectory while keeping the relevant points which preserve
important information. The benefits include storage reduction, computational
expense, while making data more manageable. Common techniques formulate a
minimization problem to be solved, where the solution is found iteratively
under some error metric, which causes the algorithms to work in super-linear
time. We present an algorithm called FastSTray, which selects the relevant
points in the trajectory in linear time by following an open loop heuristic
approach. While most current trajectory simplification algorithms are tailored
for GPS trajectories, our approach focuses on smooth trajectories for robot
programming by demonstration recorded using motion capture systems.Two
variations of the algorithm are presented: 1. aims to preserve shape and
temporal information; 2. preserves only shape information. Using the points in
the simplified trajectory we use cubic splines to interpolate between these
points and recreate the original trajectory. The presented algorithm was tested
on trajectories recorded from a hand-tracking system. It was able to eliminate
about 90% of the points in the original trajectories while maintaining errors
between 0.78-2cm which corresponds to 1%-2.4% relative error with respect to
the bounding box of the trajectories.


title: Medium Induced Transverse Momentum Broadening in Hard Processes

abstract:
  Using deep inelastic scattering on a large nucleus as an example, we consider
the transverse momentum broadening of partons in hard processes in the presence
of medium. We find that one can factorize the vacuum radiation contribution and
medium related $P_T$ broadening effects into the Sudakov factor and medium
dependent distributions, respectively. Our derivations can be generalized to
other hard processes, such as dijet productions, which can be used as a probe
to measure the medium $P_T$ broadening effects in heavy ion collisions when
Sudakov effects are not overwhelming.


title: The Majorana Demonstrator search for neutrinoless double beta decay

abstract:
  The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an
ultra-low background, modular, HPGe detector array with a mass of 44.8-kg (29.7
kg enriched >88% in Ge-76) to search for neutrinoless double beta decay in
Ge-76. The next generation of tonnescale Ge-based neutrinoless double beta
decay searches will probe the neutrino mass scale in the inverted-hierarchy
region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward
to achieve a background rate at or below 1 count/tonne/year in the 4 keV region
of interest around the Q-value of 2039 keV. The MAJORANA DEMONSTRATOR follows a
modular implementation to be easily scalable to the next generation experiment.
First data taken with the DEMONSTRATOR are introduced here.


title: Two-body physics in the Su-Schrieffer-Heeger model

abstract:
  We consider two interacting bosons in a dimerized Su-Schrieffer-Heeger (SSH)
lattice. We identify a rich variety of two-body states. In particular, for open
boundary conditions and moderate interactions, edge bound states (EBS) are
present even for the dimerization that does not sustain single-particle edge
states. Moreover, for large values of the interactions, we find a breaking of
the standard bulk-boundary correspondence. Based on the mapping of two
interacting particles in one dimension onto a single particle in two
dimensions, we propose an experimentally realistic coupled optical fibers setup
as quantum simulator of the two-body SSH model. This setup is able to highlight
the localization properties of the states as well as the presence of a resonant
scattering mechanism provided by a bound state that crosses the scattering
continuum, revealing the closed-channel population in real time and real space.


title: Bisectors determining unique pairs of points in the bidisk

abstract:
  Bisectors are equidistant hypersurfaces between two points and are basic
objects in a metric geometry. They play an important part in understanding the
action of subgroups of isometries on a metric space. In many metric geometries
(spherical, Euclidean, hyperbolic, complex hyperbolic, to name a few) bisectors
do not uniquely determine a pair of points, in the following sense\,:
completely different sets of points share a common bisector. The above examples
of this non-uniqueness are all rank $1$ symmetric spaces.
  However, as we show in this paper, bisectors in the usual $L^2$ metric are
such for a unique pair of points in the rank $2$ geometry $\mathbb{H}^2
\times\mathbb{H}^2$.


title: Modified Relay Selection and Circuit Selection for Faster Tor

abstract:
  Users of the Tor anonymity system suffer from lessthan- ideal performance, in
part because circuit building and selection processes are not tuned for speed.
In this paper, we examine both the process of selecting among pre-built
circuits and the process of selecting the path of relays for use in building
new circuits to improve performance while maintaining anonymity. First, we show
that having three pre-built circuits available allows the Tor client to
identify fast circuits and improves median time to first byte (TTFB) by 15%
over congestion-aware routing, the current state-of-the-art method. Second, we
propose a new path selection algorithm that includes broad geographic location
information together with bandwidth to reduce delays. In Shadow simulations, we
find 20% faster median TTFB and 11% faster median total download times over
congestion-aware routing for accessing webpage-sized objects. Our security
evaluations show that this approach leads to better or equal security against a
generic relay-level adversary compared to Tor, but increased vulnerability to
targeted attacks. We explore this trade-off and find settings of our system
that offer good performance, modestly better security against a generic
adversary, and only slightly more vulnerability to a targeted adversary.


title:
A pathological construction for real functions with large collections of
  level sets

abstract:
  Consider all the level sets of a real function. We can group these level sets
according to their Hausdorff dimensions. We show that the Hausdorff dimension
of the collection of all level sets of a given Hausdorff dimension can be
arbitrarily close to 1, even if the function is differentiable to some level.
By definition of Hausdorff dimension it is clear, for any real function $f(x)$
and any $\alpha \in [0,1]$, that $\dim_{H} \left\{ {0.03in} y \ : \ \dim_{H}
(f^{-1}(y)) \geq \alpha {0.03in} \right\} \leq 1$. What is surprising, and what
we show, is that this is actually a sharp bound. That is, $$\sup \left\{
{0.03in} \dim_{H} \left\{ {0.03in} y \ : \ \dim_{H} (f^{-1}(y)) = 1 {0.03in}
\right\} \ : \ f \in C^{k} {0.03in} \right\} = 1,$$ for any $k \in
\mathbb{Z}_{\geq 0}$.


title: Prospects for Characterizing the Atmosphere of Proxima Centauri b

abstract:
  The newly detected Earth-mass planet in the habitable zone of Proxima
Centauri could potentially host life - if it has an atmosphere that supports
surface liquid water. We show that thermal phase curve observations with the
James Webb Space Telescope (JWST) from 5-12 microns can be used to test the
existence of such an atmosphere. We predict the thermal variation for a bare
rock versus a planet with 35% heat redistribution to the nightside and show
that a JWST phase curve measurement can distinguish between these cases at
$4\sigma$ confidence, assuming photon-limited precision. We also consider the
case of an Earth-like atmosphere, and find that the ozone 9.8 micron band could
be detected with longer integration times (a few months). We conclude that JWST
observations have the potential to put the first constraints on the possibility
of life around the nearest star to the Solar System.


title: Strain-induced spin resonance shifts in silicon devices

abstract:
  In spin-based quantum information processing devices, the presence of control
and detection circuitry can change the local environment of a spin by
introducing strain and electric fields, altering its resonant frequencies.
These resonance shifts can be large compared to intrinsic spin line-widths and
it is therefore important to study, understand and model such effects in order
to better predict device performance. Here we investigate a sample of bismuth
donor spins implanted in a silicon chip, on top of which a superconducting
aluminium micro-resonator has been fabricated. The on-chip resonator provides
two functions: first, it produces local strain in the silicon due to the larger
thermal contraction of the aluminium, and second, it enables sensitive electron
spin resonance spectroscopy of donors close to the surface that experience this
strain. Through finite-element strain simulations we are able to reconstruct
key features of our experiments, including the electron spin resonance spectra.
Our results are consistent with a recently discovered mechanism for producing
shifts of the hyperfine interaction for donors in silicon, which is linear with
the hydrostatic component of an applied strain.


title:
Lower bounds for the smallest singular value of structured random
  matrices

abstract:
  We obtain lower tail estimates for the smallest singular value of random
matrices with independent but non-identically distributed entries.
Specifically, we consider $n\times n$ matrices with complex entries of the form
\[ M = A\circ X + B = (a_{ij}\xi_{ij} + b_{ij}) \] where $X=(\xi_{ij})$ has iid
centered entries of unit variance and $A$ and $B$ are fixed matrices. In our
main result we obtain polynomial bounds on the smallest singular value of $M$
for the case that $A$ has bounded (possibly zero) entries, and $B= Z\sqrt{n}$
where $Z$ is a diagonal matrix with entries bounded away from zero. As a
byproduct of our methods we can also handle general perturbations $B$ under
additional hypotheses on $A$, which translate to connectivity hypotheses on an
associated graph. In particular, we extend a result of Rudelson and Zeitouni
for Gaussian matrices to allow for general entry distributions satisfying some
moment hypotheses. Our proofs make use of tools which (to our knowledge) were
previously unexploited in random matrix theory, in particular Szemer\'edi's
Regularity Lemma, and a version of the Restricted Invertibility Theorem due to
Spielman and Srivastava.


title: Algorithms for Colourful Simplicial Depth and Medians in the Plane

abstract:
  The colourful simplicial depth of a point x in the plane relative to a
configuration of n points in k colour classes is exactly the number of closed
simplices (triangles) with vertices from 3 different colour classes that
contain x in their convex hull. We consider the problems of efficiently
computing the colourful simplicial depth of a point x, and of finding a point,
called a median, that maximizes colourful simplicial depth.
  For computing the colourful simplicial depth of x, our algorithm runs in time
O(n log(n) + k n) in general, and O(kn) if the points are sorted around x. For
finding the colourful median, we get a time of O(n^4). For comparison, the
running times of the best known algorithm for the monochrome version of these
problems are O(n log(n)) in general, improving to O(n) if the points are sorted
around x for monochrome depth, and O(n^4) for finding a monochrome median.


title: Regularity for a fractional p-Laplace equation

abstract:
  In this note we consider regularity theory for a fractional $p$-Laplace
operator which arises in the complex interpolation of the Sobolev spaces, the
$H^{s,p}$-Laplacian. We obtain the natural analogue to the classical
$p$-Laplacian situation, namely $C^{s+\alpha}_{loc}$-regularity for the
homogeneous equation.


title: Extensions of local fields and elementary symmetric polynomials

abstract:
  Let $K$ be a local field whose residue field has characteristic $p$ and let
$L/K$ be a finite separable totally ramified extension of degree $n=up^{\nu}$.
Let $\sigma_1,\dots,\sigma_n$ denote the $K$-embeddings of $L$ into a separable
closure $K^{sep}$ of $K$. For $1\le h\le n$ let $e_h(X_1,\dots,X_n)$ denote the
$h$th elementary symmetric polynomial in $n$ variables, and for $\alpha\in L$
set $E_h(\alpha) =e_h(\sigma_1(\alpha),\dots,\sigma_n(\alpha))$. Set
$j=\min\{v_p(h),\nu\}$. We show that for $r\in\mathbb{Z}$ we have
$E_h(\mathcal{M}_L^r)\subset \mathcal{M}_K^{\lceil(i_j+hr)/n\rceil}$, where
$i_j$ is the $j$th index of inseparability of $L/K$. In certain cases we also
show that $E_h(\mathcal{M}_L^r)$ is not contained in any higher power of
$\mathcal{M}_K$.


title: The intrinsic line width of the Fe Ka line of AGN

abstract:
  X-ray fluorescent lines are unique features of the reflection spectrum of the
cold torus when irradiated by the central AGN. Their intrinsic line widths can
be used to probe the line-emitting region. The line widths of the Fe \Ka line
measured from the first order Chandra High Energy Grating (HEG) spectra are
$3-5$ times larger than those measured with the Si \Ka line for Circinus, Mrk
3, and NGC 1068. Because the observed Si \Ka and Fe \Ka lines are not
necessarily coming from the same physical region, it is uncertain whether the
line widths of the Fe \Ka line are over-estimated or not. We measured the
intrinsic line widths of the Fe \Ka line of several nearby bright AGN using the
second and third order Chandra HEG spectra, whose spectral resolutions are
better than the first order data. We found the measured widths are all smaller
than those from the first order data. The results clearly show that the widths
of the Fe \Ka line measured from the first order HEG data are over-estimated.
It indicates that the Fe \Ka lines of the studied sources are originating from
regions around the cold dusty torus.


title:
Connectivity-Aware Traffic Phase Scheduling for Heterogeneously
  Connected Vehicles

abstract:
  We consider a transportation system of heterogeneously connected vehicles,
where not all vehicles are able to communicate. Heterogeneous connectivity in
transportation systems is coupled to practical constraints such that (i) not
all vehicles may be equipped with devices having communication interfaces, (ii)
some vehicles may not prefer to communicate due to privacy and security
reasons, and (iii) communication links are not perfect and packet losses and
delay occur in practice. In this context, it is crucial to develop control
algorithms by taking into account the heterogeneity. In this paper, we
particularly focus on making traffic phase scheduling decisions. We develop a
connectivity-aware traffic phase scheduling algorithm for heterogeneously
connected vehicles that increases the intersection efficiency (in terms of the
average number of vehicles that are allowed to pass the intersection) by taking
into account the heterogeneity. The simulation results show that our algorithm
significantly improves the efficiency of intersections as compared to the
baselines.


title: On the Nash modification of a germ of complex analytic singularity

abstract:
  For a germ $(X,0) \subset (\mathbb{C}^n,0)$ of reduced, equidimensional
complex analytic singularity its Nash modification can be constructed as an
analytic subvariety $ Z \subset \mathbb{C}^n \times G(k,n)$. We give a
characterization of the subvarieties of $\mathbb{C}^n \times G(k,n)$ that are
the Nash modification of its image under the projection to $\mathbb{C}^n$. This
result generalizes the characterization of conormal varieties as Legendrian
subvarieties of $\mathbb{C}^n \times \check{\mathbb{P}}^{n-1}$ with its
canonical contact structure. As a by-product we define the $d$-conormal space
of $(X,0)$ for any $d \in \{k, \ldots, n-1\}$ which is a generalization of both
the Nash modification and the conormal variety of $(X,0)$.


title:
Production of large $^{41}$K Bose-Einstein condensates using D1 gray
  molasses

abstract:
  We use D1 gray molasses to achieve Bose-Einstein condensation of a large
number of $^{41}$K atoms in an optical dipole trap. By combining a new
configuration of compressed-MOT with D1 gray molasses, we obtain a cold sample
of $2.4\times10^9$ atoms with a temperature as low as 42 $\mu$K. After
magnetically transferring the atoms into the final glass cell, we perform a
two-stage evaporative cooling. A condensate with up to $1.2\times10^6$ atoms in
the lowest Zeeman state $|F=1,m_F=1\rangle$ is achieved in the optical dipole
trap. Furthermore, we observe two narrow Feshbach resonances in the lowest
hyperfine channel, which are in good agreement with theoretical predictions.


title: Site occupation of indium and jump frequencies of cadmium in FeGa3

abstract:
  Perturbed angular correlation (PAC) measurements using the In-111 probe were
carried out on FeGa3 as part of a broader investigation of indium site
occupation and cadmium diffusion in intermetallic compounds. One PAC signal was
observed with hyperfine parameters w1 = 513.8(1) Mrad/s and eta = 0.939(2) at
room temperature. By comparison with quadrupole frequencies observed in PAC
measurements on isostructural RuIn3, it was determined that indium occupies
only the 8j site in the FeGa3 structure, denoted Ga(2) below because two out of
the three Ga sites have this point symmetry. PAC spectra at elevated
temperature exhibited damping characteristic of electric field gradients (EFGs)
that fluctuate as Cd probes jump among Ga(2) sites within the lifetime of the
excited PAC level. A stochastic model for the EFG fluctuations based on four
conceivable, single-step jump-pathways connecting one Ga(2) site to neighboring
Ga(2) sites was developed and used to fit PAC spectra. The four pathways lead
to two observable EFG reorientation rates, and these reorientation rates were
found to be strongly dependent on EFG orientation. Calculations using density
functional theory were used to reduce the number of unknowns in the model with
respect to EFG orientation. This made it possible to determine with reasonable
precision the total jump rate of Cd among Ga(2) sites that correspond to a
change in mirror plane orientation of site-symmetry. This total jump rate was
found to be thermally activated with an activation enthalpy of 1.8(1) eV.


title: Mode selection in compressible active flow networks

abstract:
  Coherent, large scale dynamics in many nonequilibrium physical, biological,
or information transport networks are driven by small-scale local energy input.
Here, we introduce and explore an analytically tractable nonlinear model for
compressible active flow networks. In contrast to thermally-driven systems, we
find that active friction selects discrete states with a limited number of
oscillation modes activated at distinct fixed amplitudes. Using perturbation
theory, we systematically predict the stationary states of noisy networks and
find good agreement with a Bayesian state estimation based on a hidden Markov
model applied to simulated time series data. Our results suggest that the
macroscopic response of active network structures, from actomyosin force
networks to cytoplasmic flows, can be dominated by a significantly reduced
number of modes, in contrast to energy equipartition in thermal equilibrium.
The model is also well-suited to study topological sound modes and spectral
band gaps in active matter.


title:
Optimal Bidding in Repeated Wireless Spectrum Auctions with Budget
  Constraints

abstract:
  Small operators who take part in secondary wireless spectrum markets
typically have strict budget limits. In this paper, we study the bidding
problem of a budget constrained operator in repeated secondary spectrum
auctions. In existing truthful auctions, truthful bidding is the optimal
strategy of a bidder. However, budget limits impact bidding behaviors and make
bidding decisions complicated, since bidders may behave differently to avoid
running out of money. We formulate the problem as a dynamic auction game
between operators, where knowledge of other operators is limited due to the
distributed nature of wireless networks/markets. We first present a Markov
Decision Process (MDP) formulation of the problem and characterize the optimal
bidding strategy of an operator, provided that opponents' bids are i.i.d. Next,
we generalize the formulation to a Markov game that, in conjunction with
model-free reinforcement learning approaches, enables an operator to make
inferences about its opponents based on local observations. Finally, we present
a fully distributed learning-based bidding algorithm which relies only on local
information. Our numerical results show that our proposed learning-based
bidding results in a better utility than truthful bidding.


title:
Cloud Radio Access Networks: Uplink Channel Estimation and Downlink
  Precoding

abstract:
  The gains afforded by cloud radio access network (C-RAN) in terms of savings
in capital and operating expenses, flexibility, interference management and
network densification rely on the presence of high-capacity low-latency
fronthaul connectivity between remote radio heads (RRHs) and baseband unit
(BBU). In light of the non-uniform and limited availability of fiber optics
cables, the bandwidth constraints on the fronthaul network call, on the one
hand, for the development of advanced baseband compression strategies and, on
the other hand, for a closer investigation of the optimal functional split
between RRHs and BBU. In this chapter, after a brief introduction to signal
processing challenges in C-RAN, this optimal function split is studied at the
physical (PHY) layer as it pertains to two key baseband signal processing
steps, namely channel estimation in the uplink and channel encoding/ linear
precoding in the downlink. Joint optimization of baseband fronthaul compression
and of baseband signal processing is tackled under different PHY functional
splits, whereby uplink channel estimation and downlink channel encoding/ linear
precoding are carried out either at the RRHs or at the BBU. The analysis, based
on information-theoretical arguments, and numerical results yields insight into
the configurations of network architecture and fronthaul capacities in which
different functional splits are advantageous. The treatment also emphasizes the
versatility of deterministic and stochastic successive convex approximation
strategies for the optimization of C-RANs.


title: Light Scalars and the Cosmos: Nambu-Goldstone and Otherwise

abstract:
  This talk focuses on the role of light scalars in cosmology, both Nambu
Goldstone bosons and pseudo moduli. The former include QCD axions, which might
constitute the dark matter, and more general axions, which, under certain
conditions, might play the role of inflatons, implementing {\it natural
inflation}. The latter are the actors in (generalized) hybrid inflation. They
rather naturally yield large field inflation, even mimicking chaotic inflation
for suitable ranges of parameters.


title: Highly polarized components of integrated pulse profiles

abstract:
  Highly polarized components of pulse profiles are investigated by analyzing
observational data and simulating the emission processes. The highly polarized
components appear at the leading or trailing part of a pulse profile, which
preferably have a flat spectrum and a flat polarization angle curve compared
with the low polarized components. By considering the emission processes and
propagation effects, we simulate the distributions of wave modes and fractional
linear polarization within the entire pulsar emission beam. We show that the
highly polarized components can appear at the leading, central, and/or trailing
parts of pulse profiles in the models, depending on pulsar geometry. The
depolarization is caused by orthogonal modes or scattering. When a sight line
cuts across pulsar emission beam with a small impact angle, the detected highly
polarized component will be of the O mode, and have a flat polarization angle
curve and/or a flat spectrum as observed. Otherwise, the highly polarized
component will be of the X mode and have a steep polarization angle curve.


title:
Ultrafast Relaxation Dynamics of Photoexcited Dirac Fermion in The Three
  Dimensional Dirac Semimetal Cadmium Arsenide

abstract:
  Three dimensional (3D) Dirac semimetals which can be seen as 3D analogues of
graphene have attracted enormous interests in research recently. In order to
apply these ultrahigh-mobility materials in future electronic/optoelectronic
devices, it is crucial to understand the relaxation dynamics of photoexcited
carriers and their coupling with lattice. In this work, we report ultrafast
transient reflection measurements of the photoexcited carrier dynamics in
cadmium arsenide (Cd3As2), which is one of the most stable Dirac semimetals
that have been confirmed experimentally. By using low energy probe photon of
0.3 eV, we probed the dynamics of the photoexcited carriers that are
Dirac-Fermi-like approaching the Dirac point. We systematically studied the
transient reflection on bulk and nanoplate samples that have different doping
intensities by tuning the probe wavelength, pump power and lattice temperature,
and find that the dynamical evolution of carrier distributions can be retrieved
qualitatively by using a two-temperature model. This result is very similar to
that of graphene, but the carrier cooling through the optical phonon couplings
is slower and lasts over larger electron temperature range because the optical
phonon energies in Cd3As2 are much lower than those in graphene.


title:
Design and Implementation of a TDD-Based 128-Antenna Massive MIMO
  Prototyping System

abstract:
  Spurred by the dramatic mobile IP growth and the emerging Internet of Things
(IoT) and cloud-based applications, wireless networking is witnessing a
paradigm shift. By fully exploiting the spatial degrees of freedom, the massive
multipleinput- multiple-output (MIMO) technology promises significant gains in
both data rates and link reliability. This paper presents a time-division
duplex (TDD)-based 128-antenna massive MIMO prototyping system designed to
operate on a 20 MHz bandwidth. Up to twelve single-antenna users can be served
by the designed system at the same time. System model is provided and
link-level simulation corresponding to our practical TDDbased massive MIMO
prototyping system is conducted to validate our design and performance of the
algorithms. Based on the system hardware design demonstrated in this paper,
both uplink real-time video and downlink data transmissions are realized, and
the experiment results show that 268.8 Mbps rate was achieved for eight
single-antenna users using QPSK modulation. The maximum spectral efficiency of
the designed system will be 80.64 bit/s/Hz by twelve single-antenna users with
256-QAM modulation.


title: Phase Transition in Conditional Curie-Weiss Model

abstract:
  This paper proposes a conditional Curie-Weiss model as a model for opinion
formation in a society polarized along two opinions, say opinions 1 and 2. The
model comes with interaction strength $\beta>0$ and bais $h$. Here the
population in question is divided into three main groups, namely: Group one
consisting of individuals who have decided on opinion 1. Let the proportion of
this group be given by $s$. Group two consisting of individauls who have chosen
opinion 2. Let $r$ be their proportion.
  Group three consisting of individuals who are yet to decide and they will
decide based on their environmental conditions. Let $1-s-r$ be the proportion
of this group. We show that the specific magnetization of the associated
conditional Curie-Weiss model has a first order phase transition (discontinuous
jump in specific magnetization) at $\beta^*=\left(1-s-r\right)^{-1}$. It is
also shown that not all the discontinuous jumps in magnetization will result in
phase change. We point out how an extention of this model could serve as a
random field Curie-Weiss model where the random field distribution has
nonvanishing mean.


title: Average activity of excitatory and inhibitory neural populations

abstract:
  We develop an extension of the Ott-Antonsen method that allows obtaining the
mean activity (spiking rate) of a population of excitable units. By means of
the Ott-Antonsen method, equations for the dynamics of the order parameters of
coupled excitatory and inhibitory populations of excitable units are obtained,
and their mean activities are computed. Two different excitable systems are
studied: Adler units and theta neurons. The resulting bifurcation diagrams are
compared to those obtained from studying the phenomenological Wilson-Cowan
model in some regions of the parameter space. Compatible behaviors, as well as
higher dimensional chaotic solutions, are observed. We study numerical
simulations to further validate the equations.


title: Scalable Compression of Deep Neural Networks

abstract:
  Deep neural networks generally involve some layers with mil- lions of
parameters, making them difficult to be deployed and updated on devices with
limited resources such as mobile phones and other smart embedded systems. In
this paper, we propose a scalable representation of the network parameters, so
that different applications can select the most suitable bit rate of the
network based on their own storage constraints. Moreover, when a device needs
to upgrade to a high-rate network, the existing low-rate network can be reused,
and only some incremental data are needed to be downloaded. We first
hierarchically quantize the weights of a pre-trained deep neural network to
enforce weight sharing. Next, we adaptively select the bits assigned to each
layer given the total bit budget. After that, we retrain the network to
fine-tune the quantized centroids. Experimental results show that our method
can achieve scalable compression with graceful degradation in the performance.


title:
Extending the exact sequence of nonabelian $H^1$, using nonabelian $H^2$
  with coefficients in crossed modules

abstract:
  In this note, following Dedecker and Debremaeker, we extend the cohomology
exact sequence for nonabelian $H^1$, using nonabelian $H^2$ with coefficients
in crossed modules.


title:
Johnson-Schechtman and Khinchine inequalities in noncommutative
  probability theory

abstract:
  We prove disjointification inequalities due to Johnson and Schechtman for
noncommutative random variables independent in the sense of Junge and Xu. In
the same setting, we also prove noncommutative Khinchine inequalities. These
inequalities are proved both for symmetric operator spaces and for modulars.


title:
$\Phi$-moment inequalities for independent and freely independent random
  variables

abstract:
  This paper is devoted to the study of $\Phi$-moments of sums of
independent/freely independent random variables. More precisely, let
$(f_k)_{k=1}^n$ be a sequence of positive (symmetrically distributed)
independent random variables and let $\Phi$ be an Orlicz function with
$\Delta_2$-condition. We provide an equivalent expression for the quantity
$\mathbb{E}(\Phi(\sum_{k=1}^n f_k))$ in term of the sum of disjoint copies of
the sequence $(f_k)_{k=1}^n.$ We also prove an analogous result in the setting
of free probability. Furthermore, we provide an equivalent characterization of
$\tau(\Phi(\sup^+_{1\leq k\leq n}x_k))$ for positive freely independent random
variables and also present some new results on free Johnson-Schechtman
inequalities in the quasi-Banach symmetric operator space.


title:
Donaldson-Thomas invariants of local elliptic surfaces via the
  topological vertex

abstract:
  We compute the Donaldson-Thomas invariants of a local elliptic surface with
section. We introduce a new computational technique which is a mixture of
motivic and toric methods. This allows us to write the partition function for
the invariants in terms of the topological vertex. Utilizing identities for the
topological vertex proved in arXiv:1603.05271, we derive product formulas for
the partition functions. The connected version of the partition function is
written in terms of Jacobi forms. In the special case where the elliptic
surface is a K3 surface, we get a derivation of the Katz-Klemm-Vafa formula for
primitive curve classes which is independent of the computation of
Kawai-Yoshioka.


title: Average of uncertainty-product for bounded observables

abstract:
  The goal of this paper is to calculate exactly the average of
uncertainty-product of two bounded observables and to establish its typicality
over the whole set of finite dimensional quantum pure states. Here we use the
uniform ensembles of pure and isospectral states as well as the states
distributed uniformly according to the measure induced by the Hilbert-Schmidt
norm. Firstly, we investigate the average uncertainty of an observable over
isospectral density matrices. By letting the isospectral density matrices be of
rank-one, we get the average uncertainty of an observable restricted to pure
quantum states. These results can help us check how large the gap is between
the uncertainty-product and any obtained lower bounds about the
uncertainty-product. Although our method in the present paper cannot give a
tighter lower bound of uncertainty-product for bounded observables, it can help
us drop any one that is not tighter than the known one substantially.


title:
Tracing technological development trajectories: A genetic knowledge
  persistence-based main path approach

abstract:
  The aim of this paper is to propose a new method to identify main paths in a
technological domain using patent citations. Previous approaches for using main
path analysis have greatly improved our understanding of actual technological
trajectories but nonetheless have some limitations. They have high potential to
miss some dominant patents from the identified main paths; nonetheless, the
high network complexity of their main paths makes qualitative tracing of
trajectories problematic. The proposed method searches backward and forward
paths from the high-persistence patents which are identified based on a
standard genetic knowledge persistence algorithm. We tested the new method by
applying it to the desalination and the solar photovoltaic domains and compared
the results to output from the same domains using a prior method. The empirical
results show that the proposed method overcomes the aforementioned drawbacks
defining main paths that are almost 10x less complex while containing more of
the relevant important knowledge than the main path networks defined by the
existing method.


title: The surface temperature of Europa

abstract:
  Previous estimates of the annual mean surface temperature of Jupiter's moon,
Europa, neglected the effect of the eccentricity of Jupiter's orbit around the
Sun, the effect of the emissivity and heat capacity of Europa's ice, the effect
of the eclipse of Europa (i.e., the relative time that Europa is within the
shadow of Jupiter), the effect of Jupiter's radiation, and the effect of
Europa's internal heating. Other studies concentrated on the diurnal cycle but
neglected some of the above factors. In addition, to our knowledge, the
seasonal cycle of the surface temperature of Europa was not estimated. Here we
systematically estimate the diurnal, seasonal and annual mean surface
temperature of Europa, when Europa's obliquity, emissivity, heat capacity, and
eclipse, as well as Jupiter's radiation, internal heating, and eccentricity,
are all taken into account. For a typical internal heating rate of 0.05 W
m$^{-2}$, the equator, pole, and the global and mean annual mean surface
temperatures are 96K, 46K, and 90K, respectively. We found that the temperature
at the high latitudes is significantly affected by the internal heating,
especially during the winter solstice, suggesting that measurements of high
latitude surface temperatures can be used to constrain the internal heating. We
also estimate the incoming solar radiation to Enceladus, the moon of Saturn.


title:
Applying Topological Persistence in Convolutional Neural Network for
  Music Audio Signals

abstract:
  Recent years have witnessed an increased interest in the application of
persistent homology, a topological tool for data analysis, to machine learning
problems. Persistent homology is known for its ability to numerically
characterize the shapes of spaces induced by features or functions. On the
other hand, deep neural networks have been shown effective in various tasks. To
our best knowledge, however, existing neural network models seldom exploit
shape information. In this paper, we investigate a way to use persistent
homology in the framework of deep neural networks. Specifically, we propose to
embed the so-called "persistence landscape," a rather new topological summary
for data, into a convolutional neural network (CNN) for dealing with audio
signals. Our evaluation on automatic music tagging, a multi-label
classification task, shows that the resulting persistent convolutional neural
network (PCNN) model can perform significantly better than state-of-the-art
models in prediction accuracy. We also discuss the intuition behind the design
of the proposed model, and offer insights into the features that it learns.


title:
Machine Learning for Atomic Forces in a Crystalline Solid:
  Transferability to Various Temperatures

abstract:
  Recently, machine learning has emerged as an alternative, powerful approach
for predicting quantum-mechanical properties of molecules and solids. Here,
using kernel ridge regression and atomic fingerprints representing local
environments of atoms, we trained a machine-learning model on a crystalline
silicon system in order to directly predict the atomic forces at a wide range
of temperatures. Our idea is to construct a machine-learning model using a
quantum-mechanical data set taken from canonical-ensemble simulations at a
higher temperature, or an upper bound of the temperature range. With our model,
the force prediction errors were about 2% or smaller with respect to the
corresponding force ranges, in the temperature region between 300 and 1650 K.
We also verified the applicability to a larger system, ensuring the
transferability with respect to system size.


title:
Raman spectroscopic features of the neutral vacancy in diamond from ab
  initio quantum-mechanical calculations

abstract:
  Quantum-mechanical ab initio calculations are performed to elucidate the
vibrational spectroscopic features of a common irradiation-induced defect in
diamond, i.e. the neutral vacancy. Raman spectra are computed analytically
through a Coupled-Perturbed-Hartree-Fock/Kohn-Sham approach as a function of
both different defect spin states and defect concentration. The experimental
Raman features of defective diamond located in the 400-1300 cm-1 spectral
range, i.e. below the first-order line of pristine diamond at 1332 cm-1 , are
well reproduced, thus corroborating the picture according to which, at low
damage densities, this spectral region is mostly affected by non-graphitic sp3
defects. No peaks above 1332 cm-1 are found, thus ruling out previous tentative
assignments of different spectral features (at 1450 and 1490 cm-1) to the
neutral vacancy. The perturbation introduced by the vacancy to the thermal
nuclear motion of carbon atoms in the defective lattice is discussed in terms
of atomic anisotropic displacement parameters (ADPs), computed from converged
lattice dynamics calculations.


title:
On weak-star convergence in product Hardy spaces on spaces of
  homogeneous type

abstract:
  A classical theorem of Jones and Journ\'e on weak-star convergence in the
Hardy space $H^1$ was generalised to the multiparameter setting by Pipher and
Treil. We prove the analogous result when the underlying space is a product
space of homogeneous type. The main tools we use for this setting are from
recent work in papers by Chen, Li and Ward and by Han, Li and Ward.


title: Cheillini integrability and quadratically damped oscillators

abstract:
  In this paper a new approach to study an equation of the Lienard type with a
strong quadratic damping is proposed based on Jacobi's last multiplier and
Cheillini's integrability condition. We obtain a closed form solution of the
transcendental characteristic equation of the Lienard type equation using the
Lambert W-function.


title:
Ultrahigh-energy neutrino follow-up of Gravitational Wave events
  GW150914 and GW151226 with the Pierre Auger Observatory

abstract:
  On September 14, 2015 the Advanced LIGO detectors observed their first
gravitational-wave (GW) transient GW150914. This was followed by a second GW
event observed on December 26, 2015. Both events were inferred to have arisen
from the merger of black holes in binary systems. Such a system may emit
neutrinos if there are magnetic fields and disk debris remaining from the
formation of the two black holes. With the surface detector array of the Pierre
Auger Observatory we can search for neutrinos with energy above 100 PeV from
point-like sources across the sky with equatorial declination from about -65
deg. to +60 deg., and in particular from a fraction of the 90% confidence-level
(CL) inferred positions in the sky of GW150914 and GW151226. A targeted search
for highly-inclined extensive air showers, produced either by interactions of
downward-going neutrinos of all flavors in the atmosphere or by the decays of
tau leptons originating from tau-neutrino interactions in the Earth's crust
(Earth-skimming neutrinos), yielded no candidates in the Auger data collected
within $\pm 500$ s around or 1 day after the coordinated universal time (UTC)
of GW150914 and GW151226, as well as in the same search periods relative to the
UTC time of the GW candidate event LVT151012. From the non-observation we
constrain the amount of energy radiated in ultrahigh-energy neutrinos from such
remarkable events.


title:
Solution of Second Order Supersymmetrical Intertwining Relations in
  Minkowski Plane

abstract:
  Supersymmetrical (SUSY) intertwining relations are generalized to the case of
quantum Hamiltonians in Minkowski space. For intertwining operators
(supercharges) of second order in derivatives the intertwined Hamiltonians
correspond to completely integrable systems with the symmetry operators of
fourth order in momenta. In terms of components, the itertwining relations
correspond to the system of nonlinear differential equations which are solvable
with the simplest - constant - ansatzes for the "metric" matrix in second order
part of the supercharges. The corresponding potentials are built explicitly
both for diagonalizable and nondiagonalizable form of "metric" matrices, and
their properties are discussed.


title: Quantum Ising Systems, Edge Modes, and Rabi Lattice

abstract:
  The thesis contains theoretical study of number of systems in low dimension,
which are related to quantum Ising model. The main results are emergence of
Majorana fermions in condensed matter system. We discuss an array of cavity-QED
system, describing atom-photon (spin-boson) interacting problem, namely Rabi
lattice model, and calculated its phase diagram. More importantly we showed
that in any dimension, the system has Ising dynamics in strong atom-photon
coupling limit. For 1D, a special relation between end-to-end spin-spin
correlation is presented, which is very much different form the bulk spin-spin
correlation. The entanglement between cavities is calculated and shown to have
maximum value at the phase transition point. Other problems we studied were the
frustrated quantum Ising model and its phase diagram as well as existence of
Majorana like edge modes in different phases of the model. The fermionic
version of the frustrated quantum Ising problem is also presented. On a
different but related note, we present some beautiful results on Falicov
Kimball (FK) model, a fermionic model similar to Hubbard model, on a square
lattice. Using a canonical representation for electrons (invented by Brijesh
Kumar), the FK model is mapped to classical Ising model (at infinite Hubbard
interaction limit) on 2D lattice. We performed classical Monte Carlo simulation
to study magnetization as a function of Hubbard interaction and also as a
function of temperature. The motivation was to study (quantum) charge
fluctuation (thus, quantum fluctuation of top of classical Ising
thermodynamics) due to finite Hubbard interaction term.
  We also devote a chapter for basic numerical techniques, such as Density
matrix Renormalization Group method, Exact diagonalization for spin system and
classical Monte Carlo simulation (for classical 2D Ising model), which we have
used in this thesis.


title: Measurement of Wave Electric Fields in Plasmas by Electro-Optic Probe

abstract:
  Electric field measurement in plasmas permits quantitative comparison between
the experiment and the simulation in this study. An electro-optic (EO) sensor
based on Pockels effect is demonstrated to measure wave electric fields in the
laboratory magnetosphere of the RT-1 device with high frequency heating
sources. This system gives the merits that electric field measurements can
detect electrostatic waves separated clearly from wave magnetic fields, and
that the sensor head is separated electrically from strong stray fields in
circumference. The electromagnetic waves are excited at the double loop antenna
for ion heating in electron cyclotron heated plasmas. In the air, the measured
wave electric fields are in good absolute agreement with those predicted by the
TASK/WF2 code. In inhomogeneous plasmas, the wave electric fields in the
peripheral region are enhanced compared with the simulated electric fields. The
potential oscillation of the antenna is one of the possible reason to explain
the experimental results qualitatively.


title: Decay estimates for wave equation with a potential on exterior domains

abstract:
  The purpose of the present paper is to establish the local energy decay
estimates and dispersive estimates for 3-dimensional wave equation with a
potential to the initial-boundary value problem on exterior domains. The
geometrical assumptions on domains are rather general, for example non-trapping
condition is not imposed in the local energy decay result. As a by-product,
Strichartz estimates is obtained too.


title: Restricted completion of sparse partial Latin squares

abstract:
  An $n \times n$ partial Latin square $P$ is called $\alpha$-dense if each row
and column has at most $\alpha n$ non-empty cells and each symbol occurs at
most $\alpha n$ times in $P$. An $n \times n$ array $A$ where each cell
contains a subset of $\{1,\dots, n\}$ is a $(\beta n, \beta n, \beta n)$-array
if each symbol occurs at most $\beta n$ times in each row and column and each
cell contains a set of size at most $\beta n$. Combining the notions of
completing partial Latin squares and avoiding arrays, we prove that there are
constants $\alpha, \beta > 0$ such that, for every positive integer $n$, if $P$
is an $\alpha$-dense $n \times n$ partial Latin square, $A$ is an $n \times n$
$(\beta n, \beta n, \beta n)$-array, and no cell of $P$ contains a symbol that
appears in the corresponding cell of $A$, then there is a completion of $P$
that avoids $A$; that is, there is a Latin square $L$ that agrees with $P$ on
every non-empty cell of $P$, and, for each $i,j$ satisfying $1 \leq i,j \leq
n$, the symbol in position $(i,j)$ in $L$ does not appear in the corresponding
cell of $A$.


title: Digital Waveguide Adiabatic Passage Part 1: Theory

abstract:
  Spatial adiabatic passage represents a new way to design integrated photonic
devices. In conventional adiabatic passage designs require smoothly varying
waveguide separations. Here we show modelling of adiabatic passage devices
where the waveguide separation is varied digitally. Despite digitisation, our
designs show robustness against variations in the input wavelength and
refractive index contrast of the waveguides relative to the cladding. This
approach to spatial adiabatic passage opens new design strategies and hence the
potential for new photonics devices.


title: Digital Waveguide Adiabatic Passage Part 2: Experiment

abstract:
  Using a femtosecond laser writing technique, we fabricate and characterise
three-waveguide digital adiabatic passage devices, with the central waveguide
digitised into five discrete waveguidelets. Strongly asymmetric behaviour was
observed, devices operated with high fidelity in the counter-intuitive scheme
while strongly suppressing transmission in the intuitive. The low differential
loss of the digital adiabatic passage designs potentially offers additional
functionality for adiabatic passage based devices. These devices operate with a
high contrast ($>\!90\%$) over a 60nm bandwidth, centered at $\sim 823$nm.


title: Drying dynamics of a charged colloidal dispersion in a confined drop

abstract:
  We performed a thorough investigation of the drying dynamics of a charged
colloidal dispersion drop in a confined geometry. We developed an original
methodology based on Raman micro-spectroscopy to measure spatially-resolved
colloids concentration profiles during the drying of the drop. These
measurements lead, for the first time, to estimates of the collective diffusion
coefficient of the dispersion over a wide range of concentration. The
collective diffusion coefficient is one order of magnitude higher than the
Stokes-Einstein estimate showing the importance of the electrostatic
interactions for the relaxation of concentration gradients. At the same time,
we also performed fluorescence imaging of tracers embedded within the
dispersion during the drying of the drop, which reveals two distinct regimes.
At early stages, concentration gradients along the drop lead to
buoyancy-induced flows. Strikingly, these flows do not influence the colloidal
concentration gradients that generate them, as the mass transport remains
dominated by diffusion. At longer time scales, the tracers trajectories reveal
the formation of a gel which dries quasi homogeneously. For such a gel, we show
using linear poro-elastic modeling, that the drying dynamics is still described
by the same transport equations as for the liquid dispersion. However, the
collective diffusion coefficient follows a modified generalized Stokes-Einstein
relation, as also demonstrated in the context of unidirectional consolidation
by Style et al. [Crust formation in drying colloidal suspensions, Style et al.,
Proc. R. Soc. A 467, 174 (2011)].


title:
SUSY Method for the Three-Dimensional Schr\"odinger Equation with
  Effective Mass

abstract:
  The three-dimensional Schr\"odinger equation with a position-dependent
(effective) mass is studied in the framework of Supersymmetrical (SUSY) Quantum
Mechanics. The general solution of SUSY intertwining relations with first order
supercharges is obtained without any preliminary constraints. Several forms of
coefficient functions of the supercharges are investigated and analytical
expressions for the mass function and partner potentials are found. As usual
for SUSY Quantum Mechanics with nonsingular superpotentials, the spectra of
intertwined Hamiltonians coincide up to zero modes of supercharges, and the
corresponding wave functions are connected by intertwining relations. All
models are partially integrable by construction: each of them has at least one
second order symmetry operator.


title:
AstroSat CZT Imager observations of GRB 151006A: timing, spectroscopy,
  and polarisation study

abstract:
  AstroSat is a multi-wavelength satellite launched on 2015 September 28. The
CZT Imager of AstroSat on its very first day of operation detected a long
duration gamma-ray burst (GRB) namely GRB 151006A. Using the off-axis imaging
and spectral response of the instrument, we demonstrate that CZT Imager can
localise this GRB correct to about a few degrees and it can provide, in
conjunction with Swift, spectral parameters similar to that obtained from
Fermi/GBM. Hence CZT Imager would be a useful addition to the currently
operating GRB instruments (Swift and Fermi). Specifically, we argue that the
CZT Imager will be most useful for the short hard GRBs by providing
localisation for those detected by Fermi and spectral information for those
detected only by Swift. We also provide preliminary results on a new exciting
capability of this instrument: CZT Imager is able to identify Compton scattered
events thereby providing polarisation information for bright GRBs. GRB 151006A,
in spite of being relatively faint, shows hints of a polarisation signal at
100-300 keV (though at a low significance level). We point out that CZT Imager
should provide significant time resolved polarisation measurements for GRBs
that have fluence 3 times higher than that of GRB 151006A. We estimate that the
number of such bright GRBs detectable by CZT Imager is 5 - 6 per year. CZT
Imager can also act as a good hard X-ray monitoring device for possible
electromagnetic counterparts of Gravitational Wave events.


title:
Zigzag antiferromagnetic ground state with anisotropic correlation
  lengths in the quasi-2D honeycomb lattice compound Na2Co2TeO6

abstract:
  The crystal structure, magnetic ground state, and the temperature dependent
microscopic spin-spin correlations of the frustrated honeycomb lattice
antiferromagnet Na2Co2TeO6 have been investigated by powder neutron
diffraction. A three dimensional (3D) long-range antiferromagnetic ordering has
been found below TN ~ 24.8 K. The magnetic ground state, determined to be
zigzag antiferromagnet [k = (1/2 0 0)], occurs due to the competing exchange
interactions up to third nearest neighbors within the honeycomb lattice. The
exceptional existence of a limited magnetic correlation length along the c axis
(perpendicular to the honeycomb layers in the ab planes) has been found within
the 3D long-range ordered state, even at 1.8 K, well below TN. The observed
limited correlation along the c axis is explained by the disorder distribution
of the Na ions within the intermediate layers. The reduced ordered moments
mCo(1) = 2.77(3) muB/Co2+ and mCo(2) = 2.45(2) muB/Co2+ at 1.8 K reflect the
persistence of spin fluctuations in the ordered state. Above TN, the presence
of short-range magnetic correlations, manifested by broad diffuse magnetic
peaks, has been found. Reverse Monte Carlo analysis of the experimental diffuse
magnetic scattering data reveals that the spin correlations are mainly confined
within the 2D honeycomb layers (ab plane) with a correlation length of ~ 12
{\AA} at 25 K. The nature of spin arrangements is found to be similar in both
the short-range and long-range ordered magnetic states. This implies that the
short-range correlation grows with decreasing temperature and leads to the
zigzag AFM ordering at T < TN. The present study provides a comprehensive
picture of the magnetic correlations over the temperature range above and below
TN and their relation to the crystal structure. The role of intermediate soft
Na-layers on the magnetic coupling between honeycomb planes is discussed.


title: Toll number of the Cartesian and the lexicographic product of graphs

abstract:
  Toll convexity is a variation of the so-called interval convexity. A tolled
walk $T$ between $u$ and $v$ in $G$ is a walk of the form $T:
u,w_1,\ldots,w_k,v,$ where $k\ge 1$, in which $w_1$ is the only neighbor of $u$
in $T$ and $w_k$ is the only neighbor of $v$ in $T$. As in geodesic or
monophonic convexity, toll interval between $u,v\in V(G)$ is a set
$T_G(u,v)=\{x\in V(G)\,:\,x \textrm{ lies on a tolled walk between } u \textrm{
and } v\}$. A set of vertices $S$ is toll convex, if $T_{G}(u,v)\subseteq S$
for all $u,v\in S$. First part of the paper reinvestigates the characterization
of convex sets in the Cartesian product of graphs. Toll number and toll hull
number of the Cartesian product of two arbitrary graphs is proven to be 2. The
second part deals with the lexicographic product of graphs. It is shown that if
$H$ is not isomorphic to a complete graph, $tn(G \circ H) \leq 3\cdot tn(G)$.
We give some necessary and sufficient conditions for $tn(G \circ H) = 3\cdot
tn(G)$. Moreover, if $G$ has at least two extreme vertices, a complete
characterization is given. Also graphs with $tn(G \circ H)=2$ are characterized
- this is the case iff $G$ has an universal vertex and $tn(H)=2$. Finally, the
formula for $tn(G \circ H)$ is given - it is described in terms of the
so-called toll-dominating triples.


title:
Knowledge Formation and Inter-Game Transfer With Classical and Quantum
  Physics

abstract:
  In order to facilitate an intuitive understanding of classical physics
concepts we have developed Potential Penguin - a game where players manipulate
the landscape around a sliding penguin in order to control its movement. The
learning goal of Potential Penguin is to familiarize players with kinetic
energy and potential energy - the energies associated with movement and
position in the landscape respectively. The game levels introduce the concepts
one by one, as players are tasked with sliding the penguin through a landscape
towards a specific location, while keeping the velocity under control. When the
player manipulates the landscape, the potential energy of the penguin is
changed, which determines the penguin's movement. To build a strong connection
between theory and game the analytical expressions for kinetic and potential
energy are displayed during play with font sizes continually growing and
shrinking according to changes in each energy type. With Potential Penguin we
hope to study whether visualizing the amount of kinetic and potential energy
through visible mathematical expressions generates a connection between the
intuitive actions taken in the game and the underlying physics concepts. The
knowledge about kinetic and potential energy gained with Potential Penguin can
also be used to understand most of the physics behind the citizen science game
Quantum Moves, which has the goal of building a working quantum computer. The
two games share the principle of the core interaction - manipulating the
potential-energy landscape. We aim to investigate whether a proficiency and
understanding of Potential Penguin predicts a better performance in Quantum
Moves and a deeper understanding of the quantum physics behind that game.


title:
A generic FPGA-based detector readout and real-time image processing
  board

abstract:
  For space-based astronomical observations, it is important to have a
mechanism to capture the digital output from the standard detector for further
on-board analysis and storage. We have developed a generic (application- wise)
field-programmable gate array (FPGA) board to interface with an image sensor, a
method to generate the clocks required to read the image data from the sensor,
and a real-time image processor system (on-chip) which can be used for various
image processing tasks. The FPGA board is applied as the image processor board
in the Lunar Ultraviolet Cosmic Imager (LUCI) and a star sensor (StarSense)
(instruments developed by our group). In this paper, we discuss the various
design considerations for this board and its applications in the future balloon
and possible space flights.


title: Observation of $J/\psi\to \gamma\eta\pi^{0}$

abstract:
  We present the first study of the process $J/\psi \rightarrow
\gamma\eta\pi^{0}$ using $(223.7\pm1.4)\times10^{6}$ $J/\psi$ events
accumulated with the BESIII detector at the BEPCII facility. The branching
fraction for $J/\psi \rightarrow \gamma\eta\pi^{0}$ is measured to be
$\mathcal{B}(J/\psi \rightarrow \gamma\eta\pi^{0})
=(2.14\pm0.18(stat)\pm0.25(syst))\times10^{-5}$. With a Bayesian approach, the
upper limits of the branching fractions $\mathcal{B}(J/\psi \rightarrow \gamma
a_{0}(980),a_0(980)\rightarrow\eta\pi^0)$ and $\mathcal{B}(J/\psi \rightarrow
\gamma a_{2}(1320),a_2(1320)\rightarrow\eta\pi^0)$ are determined to be
$2.5\times10^{-6}$ and $6.6\times10^{-6}$ at the 95\% confidence level,
respectively. All of these measurements are given for the first time.


title:
Emergence of a higher energy structure in strong field ionization with
  inhomogeneous electric fields

abstract:
  Studies of strong field ionization have historically relied on the strong
field approximation, which neglects all spatial dependence in the forces
experienced by the electron after ionization. More recently, the small spatial
inhomogeneity introduced by the long-range Coulomb potential has been linked to
a number of important features in the photoelectron spectrum, such as Coulomb
asymmetry, Coulomb focusing, and the low energy structure (LES). Here, we
demonstrate by combined quantum and classical simulations that a small
time-varying spatial dependence in the laser electric field creates a prominent
higher energy peak at energies above the "classical cut-off" for direct
electrons. This higher energy structure (HES) originates from direct electrons
ionized near the peak of a single half-cycle of the laser pulse. The HES is
separated from all other ionization events (providing sub-cycle resolution) and
is highly sensitive to the carrier envelope phase (CEP). The large accumulation
of electrons with tuneable energy suggests a promising method for creating a
localized source of electron pulses of attosecond duration using tabletop laser
technology.


title: Algebraic $K$-theory and a semi-finite Fuglede-Kadison determinant

abstract:
  In this paper we apply algebraic $K$-theory techniques to construct a
Fuglede-Kadison type determinant for a semi-finite von Neumann algebra equipped
with a fixed trace. Our construction is based on the approach to determinants
for Banach algebras developed by Skandalis and de la Harpe. This approach can
be extended to the semi-finite case since the first topological $K$-group of
the trace ideal in a semi-finite von Neumann algebra is trivial. On our way we
also improve the methods of Skandalis and de la Harpe by considering relative
$K$-groups with respect to an ideal instead of the usual absolute $K$-groups.
Our construction recovers the determinant homomorphism introduced by Brown, but
all the relevant algebraic properties are automatic due to the algebraic
$K$-theory framework.


title: Controlled variation of the refractive index in ion-damaged diamond

abstract:
  A fine control of the variation of the refractive index as a function of
structural damage is essential in the fabrication of diamond-based optical and
photonic devices. We report here about the variation of the real part of the
refractive index at lambda=632.8 nm in high quality single crystal diamond
damaged with 2 and 3 MeV protons at low-medium fluences (10^13 - 10^17 ions
cm^-2). After implanting the samples in 125x125 um^2 areas with a raster
scanning ion microbeam, the variation of optical thickness of the implanted
regions was measured with laser interferometric microscopy. The results were
analyzed with a model based on the specific damage profile. The technique
allows the direct fabrication of optical structures in bulk diamond based on
the localized variation of the refractive index, which will be explored in
future works.


title:
Multivariate integration over $\R^s$ with exponential rate of
  convergence

abstract:
  In this paper we analyze the approximation of multivariate integrals over the
Euclidean plane for functions which are analytic. We show explicit upper bounds
which attain the exponential rate of convergence. We use an infinite grid with
different mesh sizes and lengths in each direction to sample the function, and
then truncate it. In our analysis, the mesh sizes and the truncated domain are
chosen by optimally balancing the truncation error and the discretization
error.
  This paper derives results in comparable function space settings, extended to
$\R^s$, as which were recently obtained in the unit cube by Dick, Larcher,
Pillichshammer and Wo{\'z}niakowski (2011).
  They showed that both lattice rules and regular grids, with different mesh
sizes in each direction, attain exponential rates, hence motivating us to
analyze only cubature formula based on regular meshes.
  We further also amend the analysis of older publications, e.g., Sloan and
Osborn (1987) and Sugihara (1987), using lattice rules on $\R^s$ by taking the
truncation error into account and extending them to take the anisotropy of the
function space into account.


title:
Proceedings First Workshop on Causal Reasoning for Embedded and
  safety-critical Systems Technologies

abstract:
  Formal approaches for automated causality analysis, fault localization,
explanation of events, accountability and blaming have been proposed
independently by several communities --- in particular, AI, concurrency,
model-based diagnosis, formal methods. Work on these topics has significantly
gained speed during the last years. The goals of CREST are to bring together
and foster exchange between researchers from the different communities, and to
present and discuss recent advances and new ideas in the field.
  The workshop program consisted of a set of invited and contributed
presentations that illustrate different techniques for, and applications of,
causality analysis and fault localization.
  The program was anchored by two keynote talks. The keynote by Hana Chockler
(King's College) provided a broad perspective on the application of causal
reasoning based on Halpern and Pearl's definitions of actual causality to a
variety of application domains ranging from formal verification to legal
reasoning. The keynote by Chao Wang (Virginia Tech) concentrated on
constraint-based analysis techniques for debugging and verifying concurrent
programs.
  Workshop papers deal with compositional causality analysis and a wide
spectrum of application for causal reasoning, such as debugging of
probabilistic models, accountability and responsibility, hazard analysis in
practice based on Lewis' counterfactuals, and fault localization and repair.


title: On a measurable analogue of small topological full groups

abstract:
  We initiate the study of a measurable analogue of small topological full
groups that we call $\mathrm L^1$ full groups. These groups are endowed with a
Polish group topology which admits a natural complete right invariant metric.
We mostly focus on $\mathrm L^1$ full groups of measure-preserving $\mathbb
Z$-actions which are actually a complete invariant of flip conjugacy.
  We prove that for ergodic actions the closure of the derived group is
topologically simple although it can fail to be simple. We also show that the
closure of the derived group is connected, and that for measure-preserving free
actions of non-amenable groups the closure of the derived group and the
$\mathrm L^1$ full group itself are never amenable.
  In the case of a measure-preserving ergodic $\mathbb Z$-action, the closure
of the derived group is shown to be the kernel of the index map. If such an
action is moreover by homeomorphism on the Cantor space, we show that the
topological full group is dense in the $\mathrm L^1$ full group. Using
Juschenko-Monod and Matui's results on topological full groups, we conclude
that $\mathrm L^1$ full groups of ergodic $\mathbb Z$-actions are amenable as
topological groups, and that they are topologically finitely generated if and
only if the $\mathbb Z$-action has finite entropy.


title: Collaborative Filtering with Recurrent Neural Networks

abstract:
  We show that collaborative filtering can be viewed as a sequence prediction
problem, and that given this interpretation, recurrent neural networks offer
very competitive approach. In particular we study how the long short-term
memory (LSTM) can be applied to collaborative filtering, and how it compares to
standard nearest neighbors and matrix factorization methods on movie
recommendation. We show that the LSTM is competitive in all aspects, and
largely outperforms other methods in terms of item coverage and short term
predictions.


title: Thermal Hall effect in a phonon-glass Ba$_3$CuSb$_2$O$_9$

abstract:
  A distinct thermal Hall signal is observed in a quantum spin liquid candidate
Ba$_3$CuSb$_2$O$_9$. The transverse thermal conduction shows a power-law
temperature dependence below 40 K where a spin gap opens. We suggest that,
through the very low longitudinal thermal conductivity and the thermal Hall
signals, a phonon Hall effect is induced by strong phonon scatterings by orphan
Cu$^{2+}$ spins formed in random domains of Cu$^{2+}$-Sb$^{5+}$ dumbbells.


title:
Stationary measures for the three-state Grover walk with one defect in
  one dimension

abstract:
  We obtain stationary measures for the one-dimensional three-state Grover walk
with one defect by solving the corresponding eigenvalue problem. We clarify a
relation between stationary and limit measures of the walk.