title: Secure Massive MIMO Systems with Limited RF Chains

abstract:
  In future practical deployments of massive multi-input multi-output (MIMO)
systems, the number of radio frequency (RF) chains at the base stations (BSs)
may be much smaller than the number of BS antennas to reduce the overall
expenditure. In this paper, we propose a novel design framework for joint data
and artificial noise (AN) precoding in a multiuser massive MIMO system with
limited number of RF chains, which improves the wireless security performance.
With imperfect channel state information (CSI), we analytically derive an
achievable lower bound on the ergodic secrecy rate of any mobile terminal (MT),
for both analog and hybrid precoding schemes. The closed-form lower bound is
used to determine optimal power splitting between data and AN that maximizes
the secrecy rate through simple one-dimensional search. Analytical and
numerical results together reveal that the proposed hybrid precoder, although
suffers from reduced secrecy rate compared with theoretical full-dimensional
precoder, is free of the high computational complexity of large-scale matrix
inversion and null-space calculations, and largely reduces the hardware cost.


title: Exploring collider signatures of the inert Higgs doublet model

abstract:
  We revisit the multilepton ($ml$) + ${E\!\!\!\!/_T}$ + $X$ signatures of the
Inert Doublet Model (IDM) of dark matter in future LHC experiments for $m =$ 3,
4 and simulate, for the first time, the $m = 5$ case. Here $X$ stands for any
number of jets. We illustrate these signals with benchmark points consistent
with the usual constraints like unitarity, perturbativity, the precision
electroweak data, the observed dark matter relic density of the Universe and,
most importantly, the stringent LHC constraints from the post Higgs ($h$)
discovery era like the measured $M_h$ and the upper bound on the invisible
width of $h$ decay which were not included in earlier analyses of multilepton
signatures. We find that if the IDM model is embedded in a grand dessert
scenario so that the unitarity constraint holds up to a very high scale, the
whole of the highly restricted parameter space allowed by the above constraints
can be probed at the LHC via the $3l$ signal for an integrated luminosity $\sim
3000 ~{\rm fb}^{-1}$. On the other hand, if any new physics shows up at a scale
$\sim$ 10~TeV, only a part of the enlarged allowed parameter space can be
probed. The $4l$ and $5l$ signals can help to discriminate among different IDM
scenarios as and when sufficient integrated luminosity accumulates.


title:
The magnetic sensitivity of the Mg ii k line to the joint action of
  Hanle, Zeeman and magneto-optical effects

abstract:
  We highlight the main results of a radiative transfer investigation on the
magnetic sensitivity of the solar Mg ii k resonance line at 2795.5 angstrom,
accounting for the joint action of the Hanle and Zeeman effects as well as
partial frequency redistribution (PRD) phenomena. We confirm that at the line
center, the linear polarization signals produced by scattering processes are
measurable, and that they are sensitive, via the Hanle effect, to magnetic
fields with strengths between 5 and 50 G, approximately. We also show that the
Zeeman effect produces conspicuous circular polarization signals, especially
for longitudinal fields stronger than 50 G, which can be used to estimate the
magnetization of the solar chromosphere via the familiar magnetograph formula.
The most novel result is that magneto-optical effects produce, in the wings of
the line, a decrease of the Q/I scattering polarization pattern and the
appearance of U/I signals (i.e., a rotation of the plane of linear
polarization). This sensitivity of the Q/I and U/I wing signals to both weak
(around 5 G) and stronger magnetic fields expands the scientific interest of
the Mg ii k line for probing the chromosphere in quiet and active regions of
the Sun


title: The 10% Gd and Ti co-doped BiFeO$_3$: A promising multiferroic material

abstract:
  In this investigation, undoped BiFeO$_3$, Gd doped
Bi$_{0.9}$Gd$_{0.1}$FeO$_3$, and Gd-Ti co-doped
Bi$_{0.9}$Gd$_{0.1}$Fe$_{1-x}$Ti$_x$O$_3$ (x = 0.10, 0.20) materials were
synthesized to report their multiferroic properties. The structural analysis
and phase identification of these multiferroic ceramics were performed using
Rietveld refinement. The Rietveld analysis has confirmed the high phase purity
of the 10% Gd-Ti co-doped Bi$_{0.9}$Gd$_{0.1}$Fe$_{0.9}$Ti$_{0.1}$O$_3$ sample
compared to that of other compositions under investigation. The major phase of
this particular composition is of rhombohedral \textit{R3c} type structure (wt%
$>99\%$) with negligible amount of impurity phases. In terms of
characterization, we address magnetic properties of this co-doped ceramic
system by applying substantially higher magnetic fields than that applied in
previously reported investigations. The dependence of temperature and maximum
applied magnetic fields on their magnetization behavior have also been
investigated. Additionally, the leakage current density has been measured to
explore its effect on the ferroelectric properties of this multiferroic system.
The outcome of this investigation suggests that the substitution of 10% Gd and
Ti in place of Bi and Fe, respectively, in BiFeO$_3$ significantly enhances its
multiferroic properties. The improved properties of this specific composition
is associated with homogeneous reduced grain size, significant suppression of
impurity phases and reduction in leakage current density which is further
asserted by polarization vs. electric field hysteresis loop measurements.


title: Distributionally Robust Games with Risk-averse Players

abstract:
  We present a new model of incomplete information games without private
information in which the players use a distributionally robust optimization
approach to cope with the payoff uncertainty. With some specific restrictions,
we show that our "Distributionally Robust Game" constitutes a true
generalization of three popular finite games. These are the Complete
Information Games, Bayesian Games and Robust Games. Subsequently, we prove that
the set of equilibria of an arbitrary distributionally robust game with
specified ambiguity set can be computed as the component-wise projection of the
solution set of a multi-linear system of equations and inequalities. For
special cases of such games we show equivalence to complete information finite
games (Nash Games) with the same number of players and same action spaces.
Thus, when our game falls within these special cases one can simply solve the
corresponding Nash Game. Finally, we demonstrate the applicability of our new
model of games and highlight its importance.


title: Open research areas in distance geometry

abstract:
  Distance Geometry is based on the inverse problem that asks to find the
positions of points, in a Euclidean space of given dimension, that are
compatible with a given set of distances. We briefly introduce the field, and
discuss some open and promising research areas.


title:
Phase transitions in distributed control systems with multiplicative
  noise

abstract:
  Contemporary technological challenges often involve many degrees of freedom
in a distributed or networked setting. Three aspects are notable: the variables
are usually associated with the nodes of a graph with limited communication
resources, hindering centralized control; the communication is subjected to
noise; and the number of variables can be very large. These three aspects make
tools and techniques from statistical physics particularly suitable for the
performance analysis of such networked systems in the limit of many variables
(analogous to the thermodynamic limit in statistical physics). Perhaps not
surprisingly, phase-transition like phenomena appear in these systems, where a
sharp change in performance can be observed with a smooth parameter variation,
with the change becoming discontinuous or singular in the limit of infinite
system size. In this paper we analyze the so called network consensus problem,
prototypical of the above considerations, that has been previously analyzed
mostly in the context of additive noise. We show that qualitatively new
phase-transition like phenomena appear for this problem in the presence of
multiplicative noise. Depending on dimensions and on the presence or absence of
a conservation law, the system performance shows a discontinuous change at a
threshold value of the multiplicative noise strength. In the absence of the
conservation law, and for graph spectral dimension less than two, the
multiplicative noise threshold (the stability margin of the control problem) is
zero. This is reminiscent of the absence of robust controllers for certain
classes of centralized control problems. Although our study involves a toy
model we believe that the qualitative features are generic, with implication
for the robust stability of distributed control systems, as well as the effect
of roundoff errors and communication noise on distributed algorithms.

categories: cond-mat.stat-mech cond-mat.dis-nn cs.SY math.OC


title:
Self-dual solitons in a $CPT$-odd and Lorentz-violating gauged $O(3)$
  sigma model

abstract:
  We have performed a complete study of self-dual configurations in a $CPT$-odd
and Lorentz-violating gauged $O(3)$ nonlinear sigma model. We have consistently
implemented the Bogomol'nyi-Prasad-Sommerfield (BPS) formalism and obtained the
correspondent differential first-order equations describing electrically
charged self-dual configurations. The total energy and magnetic flux of the
vortices, besides being proportional to the winding number, also depend
explicitly on the Lorentz-violating coefficients belonging to the sigma sector.
The total electrical charge is proportional to the magnetic flux such as it
occurs in Chern-Simons models. The Lorentz violation in the sigma sector allows
one to interpolate between Lorentz-violating versions of some sigma models: the
gauged $O(3)$ sigma model and the Maxwell-Chern-Simons $O(3)$ sigma model. The
Lorentz violation enhances the amplitude of the magnetic field and BPS energy
density near the origin, augmenting the deviation in relation to the solutions
deprived of Lorentz violation.


title: Shape and coarsening dynamics of strained islands

abstract:
  We investigate the formation and the coarsening dynamics of islands in a
strained epitaxial semi-conductor film. These islands are commonly observed in
thin films undergoing a morphological instability due to the presence of the
elasto capillary effect. We first describe both analytically and numerically
the formation of an equilibrium island using a two dimensional continuous
model. We have found that these equilibrium island-like solutions have a
maximum height $h_0$ and they sit on top of a flat wetting layer with a
thickness $h_w$. We then consider two islands and we report that they undergo a
non-interrupted coarsening that follows a two stage dynamics. The first stage
may be depicted by a quasi-static dynamics, where the mass transfers are
proportional to the chemical potential difference of the islands. It is
associated with a time scale $t_c$ that is function of the distance $d$ between
the islands, and leads to the shrinkage of the smallest island. Once its height
becomes smaller than a minimal equilibrium height $h_{0}^{*}$, its mass spreads
over the entire system. Our results pave the way for a future analysis of
coarsening of an assembly of islands.


title: The Statistical Mechanics of Human Weight Change

abstract:
  In the context of the global obesity epidemic, it is important to know who
becomes obese and why. However, the processes that determine the changing shape
of Body Mass Index (BMI) distributions in high-income societies are not
well-understood. Here we establish the statistical mechanics of human weight
change, providing a fundamental new understanding of human weight
distributions. By compiling and analysing the largest data set so far of
year-over-year BMI changes, we find, strikingly, that heavy people on average
strongly decrease their weight year-over-year, and light people increase their
weight. This drift towards the centre of the BMI distribution is balanced by
diffusion resulting from random fluctuations in diet and physical activity that
are, notably, proportional in size to BMI. We formulate a stochastic
mathematical model for BMI dynamics, deriving a theoretical shape for the BMI
distribution and offering a mechanism to explain the ongoing right-skewed
broadening of BMI distributions over time. The model also provides new
quantitative support for the hypothesis that peer-to-peer social influence
plays a measurable role in BMI dynamics. More broadly, our results demonstrate
a remarkable analogy with drift-diffusion mechanisms that are well-known from
the physical sciences and finance.


title: Continuous spin gauge field in (A)dS space

abstract:
  Totally symmetric continuous spin field propagating in (A)dS is studied.
Lagrangian gauge invariant formulation for such field is developed. Lagrangian
of continuous spin field is constructed in terms of double traceless tensor
fields, while gauge transformations are constructed in terms of traceless gauge
transformation parameters. de Donder like gauge condition that leads to simple
gauge fixed Lagrangian is found. Gauge-fixed Lagrangian invariant under global
BRST transformations is presented. The BRST Lagrangian is used for computation
of a partition function. It is demonstrated that the partition function of the
continuous spin field is equal to one. Various decoupling limits of the
continuous spin field are also studied.


title:
The Detection of Diffuse Extended Structure in 3C~273: Implications for
  Jet Power

abstract:
  We present deep Very Large Array imaging of 3C~273 in order to determine the
diffuse, large scale radio structure of this famous radio-loud quasar. Diffuse
extended structure (radio lobes) is detected for the first time in these
observations as a consequence of high dynamic range in the 327.5 and 1365 MHz
images. This emission is used to estimate a time averaged jet power, $7.2
\times 10^{43} \rm{~ergs~s^{-1}} < \overline{Q} < 3.7 \times 10^{44}
\rm{~ergs~s^{-1}}$. Brightness temperature arguments indicate consistent values
of the time variability Doppler factor and the compactness Doppler factor for
the inner jet, $\delta \gtrsim 10$. Thus, the large apparent broadband
bolometric luminosity of the jet, $\sim 3 \times 10^{46}\rm{~ergs~s^{-1}}$,
corresponds to a modest intrinsic luminosity $\gtrsim
10^{42}\rm{~ergs~s^{-1}}$, or $\sim 1\%$ of $\overline{Q}$. In summary, we find
that 3C~273 is actually a "typical" radio loud quasar contrary to suggestions
in the literature. The modest $\overline{Q}$ is near the peak of the luminosity
distribution for radio loud quasars and it is consistent with the current rate
of dissipation emitted from millimeter wavelengths to gamma rays. The extreme
core-jet morphology is an illusion from a near pole-on line of sight to a
highly relativistic jet that produces a Doppler enhanced glow that previously
swamped the lobe emission. 3C~273 apparently has the intrinsic kpc scale
morphology of a classical double radio source, but it is distorted by an
extreme Doppler aberration.


title: Experimental observation of polarization-dependent optical vortex beams

abstract:
  We report the experimental demonstration of the induced
polarization-dependent optical vortex beams. We use the Talbot configuration as
a method to probe this effect. In particular, our simple experiment shows the
direct measurement of this observation. Our experiment can exhibit clearly the
combination between the polarization and orbital angular momentum (OAM) states
of light. This implementation might be useful for further studies in the
quantum system or quantum information.


title:
Kernel Selection using Multiple Kernel Learning and Domain Adaptation in
  Reproducing Kernel Hilbert Space, for Face Recognition under Surveillance
  Scenario

abstract:
  Face Recognition (FR) has been the interest to several researchers over the
past few decades due to its passive nature of biometric authentication. Despite
high accuracy achieved by face recognition algorithms under controlled
conditions, achieving the same performance for face images obtained in
surveillance scenarios, is a major hurdle. Some attempts have been made to
super-resolve the low-resolution face images and improve the contrast, without
considerable degree of success. The proposed technique in this paper tries to
cope with the very low resolution and low contrast face images obtained from
surveillance cameras, for FR under surveillance conditions. For Support Vector
Machine classification, the selection of appropriate kernel has been a widely
discussed issue in the research community. In this paper, we propose a novel
kernel selection technique termed as MFKL (Multi-Feature Kernel Learning) to
obtain the best feature-kernel pairing. Our proposed technique employs a
effective kernel selection by Multiple Kernel Learning (MKL) method, to choose
the optimal kernel to be used along with unsupervised domain adaptation method
in the Reproducing Kernel Hilbert Space (RKHS), for a solution to the problem.
Rigorous experimentation has been performed on three real-world surveillance
face datasets : FR\_SURV, SCface and ChokePoint. Results have been shown using
Rank-1 Recognition Accuracy, ROC and CMC measures. Our proposed method
outperforms all other recent state-of-the-art techniques by a considerable
margin.


title: 3D hybrid modeling of vascular network formation

abstract:
  We develop an agent-based model of vasculogenesis, the de novo formation of
blood vessels. Endothelial cells in the vessel network are viewed as linearly
elastic spheres and are of two types: vessel elements are contained within the
network; tip cells are located at endpoints. Tip cells move in response to
forces due to interactions with neighbouring vessel elements, the local tissue
environment, chemotaxis and a persistence force modeling their tendency to
continue moving in the same direction. Vessel elements experience similar
forces but not chemotaxis. An angular persistence force representing local
tissue interactions stabilises buckling instabilities due to proliferation.
Vessel elements proliferate, at rates that depend on their degree of stretch:
elongated elements proliferate more rapidly than compressed elements. Following
division, new cells are more likely to form new sprouts if the parent vessel is
highly compressed and to be incorporated into the parent vessel if it is
stretched.
  Model simulations reproduce key features of vasculogenesis. Parameter
sensitivity analyses reveal significant changes in network size and morphology
on varying the chemotactic sensitivity of tip cells, and the sensitivities of
the proliferation rate and sprouting probability to mechanical stretch. Varying
chemotactic sensitivity also affects network directionality. Branching and
network density are influenced by the sprouting probability. Glyphs depicting
multiple network properties show how network quantities change over time and as
model parameters vary. We also show how glyphs constructed from in vivo data
could be used to discriminate between normal and tumour vasculature and,
ultimately, for model validation. We conclude that our biomechanical hybrid
model generates vascular networks similar to those generated from in vitro and
in vivo experiments.


title:
Wireless Vehicular Networks in Emergencies: A Single Frequency Network
  Approach

abstract:
  Obtaining high quality sensor information is critical in vehicular
emergencies. However, existing standards such as IEEE 802.11p/DSRC and LTE-A
cannot support either the required data rates or the latency requirements. One
solution to this problem is for municipalities to invest in dedicated base
stations to ensure that drivers have the information they need to make safe
decisions in or near accidents. In this paper we further propose that these
municipality-owned base stations form a Single Frequency Network (SFN). In
order to ensure that transmissions are reliable, we derive tight bounds on the
outage probability when the SFN is overlaid on an existing cellular network.
Using our bounds, we propose a transmission power allocation algorithm. We show
that our power allocation model can reduce the total instantaneous SFN
transmission power up to $20$ times compared to a static uniform power
allocation solution, for the considered scenarios. The result is particularly
important when base stations rely on an off-grid power source (i.e.,
batteries).


title:
Privacy-guaranteed Two-Agent Interactions Using Information-Theoretic
  Mechanisms

abstract:
  This paper introduces a multi-round interaction problem with privacy
constraints between two agents that observe correlated data. The agents
alternately share data with one another for a total of K rounds such that each
agent initiates sharing over K/2 rounds. The interactions are modeled as a
collection of K random mechanisms (mappings), one for each round. The goal is
to jointly design the K private mechanisms to determine the set of all
achievable distortion-leakage pairs at each agent. Arguing that a mutual
information-based leakage metric can be appropriate for streaming data
settings, this paper: (i) determines the set of all achievable distortion-
leakage tuples ; (ii) shows that the K mechanisms allow for precisely composing
the total privacy budget over K rounds without loss; and (ii) develops
conditions under which interaction reduces the net leakage at both agents and
illustrates it for a specific class of sources. The paper then focuses on
log-loss distortion to better understand the effect on leakage of using a
commonly used utility metric in learning theory. The resulting interaction
problem leads to a non-convex sum-leakage-distortion optimization problem that
can be viewed as an interactive version of the information bottleneck problem.
A new merge-and-search algorithm that extends the classical agglomerative
information bottleneck algorithm to the interactive setting is introduced to
determine a provable locally optimal solution. Finally, the benefit of
interaction under log-loss is illustrated for specific source classes and the
optimality of one-shot is proved for Gaussian sources under both mean-square
and log-loss distortions constraints.


title: Darwini: Generating realistic large-scale social graphs

abstract:
  Synthetic graph generators facilitate research in graph algorithms and
processing systems by providing access to data, for instance, graphs resembling
social networks, while circumventing privacy and security concerns.
Nevertheless, their practical value lies in their ability to capture important
metrics of real graphs, such as degree distribution and clustering properties.
Graph generators must also be able to produce such graphs at the scale of
real-world industry graphs, that is, hundreds of billions or trillions of
edges.
  In this paper, we propose Darwini, a graph generator that captures a number
of core characteristics of real graphs. Importantly, given a source graph, it
can reproduce the degree distribution and, unlike existing approaches, the
local clustering coefficient and joint-degree distributions. Furthermore,
Darwini maintains metrics such node PageRank, eigenvalues and the K-core
decomposition of a source graph. Comparing Darwini with state-of-the-art
generative models, we show that it can reproduce these characteristics more
accurately. Finally, we provide an open source implementation of our approach
on the vertex-centric Apache Giraph model that allows us to create synthetic
graphs with one trillion edges.


title:
Spiral structures and temperature distribution in the quiescent
  accretion disc of the cataclysmic binary V2051 Ophiuchi

abstract:
  We present the capabilities of our new code for obtaining Doppler maps
implementing the maximum likelihood approach. As test data, we used
observations of the dwarf nova V2051 Ophiuchi. The system was observed in
quiescence at least 16 d before the onset of the next outburst. Using Doppler
maps obtained for ten emission lines covering three orbital cycles, we detected
spiral structures in the accretion disc of V2051 Oph. However, these structures
could be biased as our data sampled the orbital period of the binary at only
eight different orbital phases. Our Doppler maps show evolution from a one-arm
wave structure in H$\alpha$ to two-armed waves in the other lines. The location
of the two-arm structures agrees with simulations showing tidally driven spiral
waves in the accretion disc. During consecutive cycles, the qualitative
characteristics of the detected structures remained similar but the central
absorption increased. For the first time, using the Doppler tomography method,
we obtained temperature maps of the accretion disc. However, taking into
account all the assumptions involved when using our method to retrieve them,
the result should be treated with caution. Our maps present a relatively flat
distribution of the temperature over the disc, showing no temperature increase
at the location of the spiral arms. Using `ring masking', we have revealed an
ionized region located close to the expected location of stream--disc
interactions. We found the average temperature of the accretion disc to be 5600
K, which is below the critical limit deduced from the disc instability model.


title:
Double parton scattering in pair-production of $J/\psi$ mesons at the
  LHC revisited

abstract:
  Double parton scattering (DPS) is studied at the example of $J/\psi$
pair-production in the LHCb and ATLAS experiments of the Large Hadron Collider
(LHC) at centre-of-mass energies of $\sqrt{S}=$ 7, 8, and 13 TeV. We report
theoretical predictions delivered to the LHCb and ATLAS collaborations adjusted
for the fiducial volumes of the corresponding measurements during Run I and
provide new predictions at 13 TeV collision energy. It is shown that DPS can
lead to noticeable contributions in the distributions of longitudinal variables
of the di-$J/\psi$ system, especially at 13 TeV. The increased DPS rate in
double $J/\psi$ production at high energies will open up more possibilities for
the separation of single parton scattering (SPS) and DPS contributions in
future studies.


title: Data Integration with High Dimensionality

abstract:
  We consider a problem of data integration. Consider determining which genes
affect a disease. The genes, which we call predictor objects, can be measured
in different experiments on the same individual. We address the question of
finding which genes are predictors of disease by any of the experiments. Our
formulation is more general. In a given data set, there are a fixed number of
responses for each individual, which may include a mix of discrete, binary and
continuous variables. There is also a class of predictor objects, which may
differ within a subject depending on how the predictor object is measured,
i.e., depend on the experiment. The goal is to select which predictor objects
affect any of the responses, where the number of such informative predictor
objects or features tends to infinity as sample size increases. There are
marginal likelihoods for each way the predictor object is measured, i.e., for
each experiment. We specify a pseudolikelihood combining the marginal
likelihoods, and propose a pseudolikelihood information criterion. Under
regularity conditions, we establish selection consistency for the
pseudolikelihood information criterion with unbounded true model size, which
includes a Bayesian information criterion with appropriate penalty term as a
special case. Simulations indicate that data integration improves upon,
sometimes dramatically, using only one of the data sources.


title: On $c_2$ invariants of 4-regular Feynman graphs

abstract:
  The obstruction for application of effective techniques like denominator
reduction for the computation of the $c_2$ invariant of Feynman graphs in
general is the absence of a 3-valent vertex for the initial steps. In this
paper such a formula for a 4-valent vertex is derived. The formula allows to
compute the $c_2$ invariant of new graphs, for instance, 4-regular graphs with
small loop number.


title: Bulk Locality and Entanglement Swapping in AdS/CFT

abstract:
  Localized bulk excitations in AdS/CFT are produced by operators which modify
the pattern of entanglement in the boundary state. We show that simple
models--consisting of entanglement swapping operators acting on a qubit system
or a free field theory--capture qualitative features of gravitational
backreaction and reproduce predictions of the Ryu-Takayanagi formula. These
entanglement swapping operators naturally admit multiple representations
associated with different degrees of freedom, thereby reproducing the code
subspace structure emphasized by Almheiri, Dong, and Harlow. We also show that
the boundary Reeh-Schlieder theorem implies that equivalence of certain
operators on a code subspace necessarily breaks down when non-perturbative
effects are taken into account (as is expected based on bulk arguments).


title: Quench dynamics of spin-imbalanced Fermi-Hubbard model in one dimension

abstract:
  We study a nonequilibrium dynamics of a one-dimensional spin-imbalanced
Fermi-Hubbard model following a quantum quench of on-site interaction,
realizable, for example, in Feshbach-resonant atomic Fermi gases. We focus on
the post-quench evolution starting from the initial BCS and
FuldeFerrell-Larkin-Ovchinnikov (FFLO) ground states and analyze the
corresponding spin-singlet, spin-triplet, density-density, and
magnetization-magnetization correlation functions. We find that beyond a
light-cone crossover time, rich post-quench dynamics leads to thermalized and
pre-thermalized stationary states that display strong dependence on the initial
ground state. For initially gapped BCS state, the long-time stationary state
resembles thermalization with the effective temperature set by the initial
value of the Hubbard interaction. In contrast, while the initial gapless FFLO
state reaches a stationary pre-thermalized form, it remains far from
equilibrium. We suggest that such post-quench dynamics can be used as a
fingerprint for identification and study of the FFLO phase.


title: Dynamical collapse for photons

abstract:
  I suggest a simple alteration of my CSL (Continuous Spontaneous Localization)
theory, replacing the mass density collapse-generating operators by
relativistic energy density operators. Some consequences of the density matrix
evolution equation are explored. First, the expression for the mean energy
increase of free particles is calculated (which, in the non-relativistic limit,
agrees with the usual result). Then, the density matrix evolution is applied to
photons. The mean rate of loss of photon number from a laser beam pulse, the
momentum distribution of the photons "excited" out of the laser beam pulse, and
the alteration of the cosmic blackbody spectrum are all treated to first order
in the collapse rate parameter $\lambda$. Associated possible experimental
limits on $\lambda$ are discussed.


title:
Arcwise connectedness of the set of ergodic measures of hereditary
  shifts

abstract:
  We show that the set of ergodic invariant measures of a shift space with a
safe symbol (this includes all hereditary shifts) is arcwise connected when
endowed with the $d$-bar metric. As a consequence the set of ergodic measures
of such a shift is also arcwise connected in the weak-star topology and the
entropy function over this set attains all values in the interval between zero
and the topological entropy of the shift (inclusive). The latter result is
motivated by a conjecture of A.~Katok.


title:
Collective Robot Reinforcement Learning with Distributed Asynchronous
  Guided Policy Search

abstract:
  In principle, reinforcement learning and policy search methods can enable
robots to learn highly complex and general skills that may allow them to
function amid the complexity and diversity of the real world. However, training
a policy that generalizes well across a wide range of real-world conditions
requires far greater quantity and diversity of experience than is practical to
collect with a single robot. Fortunately, it is possible for multiple robots to
share their experience with one another, and thereby, learn a policy
collectively. In this work, we explore distributed and asynchronous policy
learning as a means to achieve generalization and improved training times on
challenging, real-world manipulation tasks. We propose a distributed and
asynchronous version of Guided Policy Search and use it to demonstrate
collective policy learning on a vision-based door opening task using four
robots. We show that it achieves better generalization, utilization, and
training times than the single robot alternative.


title: Global existence for quasilinear wave equations close to Schwarzschild

abstract:
  In this article we study the quasilinear wave equation $\Box_{g(u, t, x)} u =
0$ where the metric $g(u, t, x)$ is close to the Schwarzschild metric. Under
suitable assumptions of the metric coefficients, and assuming that the initial
data for $u$ is small enough, we prove global existence of the solution. The
main technical result of the paper is a local energy estimate for the linear
wave equation on metrics with slow decay to the Schwarzschild metric.


title:
Rigidity versus flexibility of the Poisson bracket with respect to the
  $L_p$-norm

abstract:
  Rigidity of the Poisson bracket with respect to the uniform norm is one of
the central phenomena discovered within function theory on symplectic
manifolds. In the present work we examine the case of $L_p$ norms with $p <
\infty$. We show that $L_p $ - Poisson bracket invariants exhibit rigid
behavior in dimension two, and we provide an evidence for their flexibility in
higher dimensions.


title: Nonuniqueness of weak solutions to the SQG equation

abstract:
  We prove that weak solutions of the inviscid SQG equations are not unique,
thereby answering Open Problem 11 in the survey arXiv:1111.2700 by De Lellis
and Sz\'ekelyhidi Jr. Moreover, we also show that weak solutions of the
dissipative SQG equation are not unique, even if the fractional dissipation is
stronger than the square root of the Laplacian.


title:
Time-periodic solutions to the Navier-Stokes equations in the
  three-dimensional whole-space with a non-zero drift term: Asymptotic profile
  at spatial infinity

abstract:
  An asymptotic expansion at spatial infinity of a weak time-periodic solution
to the Navier-Stokes equations with a non-zero drift term in the
three-dimensional whole-space is carried out. The asymptotic profile is
explicitly identified and expressed in terms of the well-known Oseen
fundamental solution. A pointwise estimate is given for the remainder term.


title:
Cross section measurement of t-channel single top quark production in pp
  collisions at sqrt(s) = 13 TeV

abstract:
  The cross section for the production of single top quarks in the t channel is
measured in proton-proton collisions at 13 TeV with the CMS detector at the
LHC. The analyzed data correspond to an integrated luminosity of 2.2 inverse
femtobarns. The event selection requires one muon and two jets where one of the
jets is identified as originating from a bottom quark. Several kinematic
variables are then combined into a multivariate discriminator to distinguish
signal from background events. A fit to the distribution of the discriminating
variable yields a total cross section of 238 +/- 13 (stat) +/- 29 (syst) pb and
a ratio of top quark and top antiquark production of R[t-ch.] = 1.81 +/- 0.18
(stat) +/- 0.15 (syst). From the total cross section the absolute value of the
CKM matrix element V[tb] is calculated to be 1.05 +/- 0.07 (exp) +/- 0.02
(theo). All results are in agreement with the standard model predictions.


title: Cooperative light scattering in any dimension

abstract:
  We present a theory of cooperative light scattering valid in any dimension:
connecting theories for an open line, open plane, and open space in the
non-relativistic regime. This theory includes near-field and dipole-orientation
effects, highlighting how field mode confinement controls the phenomena. We
present a novel experimental implementation for planar collective effects.


title: Constraints on Relaxion Windows

abstract:
  We examine the low energy phenomenology of the relaxion solution to the weak
scale hierarchy problem. Assuming that the Hubble friction is responsible for a
dissipation of the relaxion energy, we identify the cosmological relaxion
window which corresponds to the parameter region compatible with a given value
of the acceptable number of inflationary $e$-foldings. We then discuss a
variety of observational constraints on the relaxion window, including those
from astrophysical and cosmological considerations. We find that majority of
the parameter space with a relaxion mass $m_\phi\gtrsim 100$ eV or a relaxion
decay constant $f\lesssim 10^7$ GeV is excluded by existing constraints. There
is an interesting parameter region with $m_\phi\sim \,0.2-10$ GeV and $f\sim\,
{\rm few}-200$ TeV, which is allowed by existing constraints, but can be probed
soon by future beam dump experiments such as the SHiP experiment, or by
improved EDM experiments.


title: Team-Optimal Distributed MMSE Estimation in General and Tree Networks

abstract:
  We construct team-optimal estimation algorithms over distributed networks for
state estimation in the finite-horizon mean-square error (MSE) sense. Here, we
have a distributed collection of agents with processing and cooperation
capabilities. These agents observe noisy samples of a desired state through a
linear model and seek to learn this state by interacting with each other.
Although this problem has attracted significant attention and been studied
extensively in fields including machine learning and signal processing, all the
well-known strategies do not achieve team-optimal learning performance in the
finite-horizon MSE sense. To this end, we formulate the finite-horizon
distributed minimum MSE (MMSE) when there is no restriction on the size of the
disclosed information, i.e., oracle performance, over an arbitrary network
topology. Subsequently, we show that exchange of local estimates is sufficient
to achieve the oracle performance only over certain network topologies. By
inspecting these network structures, we propose recursive algorithms achieving
the oracle performance through the disclosure of local estimates. For practical
implementations we also provide approaches to reduce the complexity of the
algorithms through the time-windowing of the observations. Finally, in the
numerical examples, we demonstrate the superior performance of the introduced
algorithms in the finite-horizon MSE sense due to optimal estimation.


title: Entanglement is an inevitable feature of any non-classical theory

abstract:
  One of the most striking features of quantum theory is the existence of
entangled states, responsible for Einstein's so called "spooky action at a
distance". These states emerge from the mathematical formalism of quantum
theory, but to date we do not have a clear idea of which physical principles
give rise to entanglement. Why does quantum theory have entangled states? Would
any theory superseding classical theory have entangled states, or is quantum
theory special? We demonstrate that without entanglement, non-classical degrees
of freedom cannot reversibly interact. We present two postulates, no-cloning /
no-broadcasting and local transitivity, either of which are sufficient to imply
the existence of entangled states in any non-classical theory with reversible
interactions. Therefore we argue that entanglement is an inevitable feature of
a non-classical universe.


title: SKA Aperture Array Mid Frequency Science Requirements

abstract:
  This document describes the top level requirements for the SKA-AAMID
telescope as determined by the SKA key science projects. These include
parameters such as operating frequency range,instantaneous bandwidth (total
processed bandwidth), field of view (or survey speed, as appropriate),
sensitivity, dynamic range, polarization purity etc. Moreover, through the
definition of a set of science requirements, this document serves as input to a
number of other documents contained within the System Requirements Review
package. (particularly SKA-TEL-MFAA-0200005: `SKA-AAMID System Requirements'
and SKA-TEL-MFAA-0200008: `MFAA Requirements').


title: Hermite rank, power rank and the generalized Weierstrass transform

abstract:
  Using the theory of generalized Weierstrass transform, we show that the
Hermite rank is identical to the power rank in the Gaussian case, and that an
Hermite rank higher than one is unstable with respect to a level shift.


title: The Slab Method to Measure the Topological Susceptibility

abstract:
  In simulations of a model with topological sectors, algorithms which proceed
in small update steps tend to get stuck in one sector, especially on fine
lattices. This distorts the numerical results; in particular it is not
straightforward to measure the topological susceptibility chi_t. We test a
method to measure chi_t even if configurations from only one sector are
available. It is based on the topological charges in sub-volumes, which we
denote as "slab". This enables the evaluation of chi_t, as we demonstrate with
numerical results for non-linear sigma-models and for 2-flavour QCD. In the
latter case, the gradient flow is applied for the smoothing of the gauge
configurations, and the slab method results for chi_t are stable over a broad
range of flow times.


title: Fixed point sets of isotopies on surfaces

abstract:
  We consider a self-homeomorphism h of some surface S. A subset F of the fixed
point set of h is said to be unlinked if there is an isotopy from the identity
to h that fixes every point of F. With Le Calvez' transverse foliations theory
in mind, we prove the existence of unlinked sets that are maximal with respect
to inclusion. As a byproduct, we prove the arcwise connectedness of the space
of homeomorphisms of the two dimensional sphere that preserves the orientation
and pointwise fix some given closed connected set F.


title:
Numerical simulation of nonlinear long waves interacting with arrays of
  emergent cylinders

abstract:
  We presented numerical simulation of long waves, interacting with arrays of
emergent cylinders inside regularly spaced patches, representing discontinues
patchy coastal vegetation. We employed the fully nonlinear and weakly
dispersive Serre-Green-Naghdi equations (SGN) until the breaking process
starts, while we changed the governing equations to nonlinear shallow water
equations (NSW) at the vicinity of the breaking-wave peak and during the runup
stage. We modeled the cylinders as physical boundaries rather than
approximating them as macro-roughness friction. We showed that the cylinders
provide protection for the areas behind them. However they might also cause
amplification in local water depth in those areas. The presented results are
extensively validated against the existing numerical and experimental data. Our
results demonstrate the capability and reliability of our model in simulating
wave interaction with emergent cylinders.


title: PTD Symmetry Protected Scattering Anomaly in Optics

abstract:
  In time-reversal invariant electronic systems the scattering matrix is
anti-symmetric. This property enables an effect, designated here as "scattering
anomaly", such that the electron transport does not suffer from back
reflections, independent of the specific geometry of the propagation path or
the presence of time-reversal invariant defects. In contrast, for a generic
time-reversal invariant photonic system the scattering matrix is symmetric and
there is no similar anomaly. Here, it is theoretically proven that despite
these fundamental differences there is a wide class of photonic platforms - in
some cases formed only by time-reversal invariant media - in which a scattering
anomaly can occur. It is shown that an optical system invariant under the
action of the composition of the parity, time-reversal, and duality operators
(PTD) is characterized by an anti-symmetric scattering matrix. Specific
examples of photonic platforms wherein the scattering anomaly occurs are given,
and it is demonstrated with full wave numerical simulations that the proposed
systems enable bidirectional waveguiding immune to arbitrary deformations of
the propagation path. Importantly, our theory unveils a new class of fully
three dimensional structures wherein the transport of light is fully protected
against reflections and uncovers unsuspected links between the electrodynamics
of reciprocal and nonreciprocal materials.


title:
Phase-Mapper: An AI Platform to Accelerate High Throughput Materials
  Discovery

abstract:
  High-Throughput materials discovery involves the rapid synthesis,
measurement, and characterization of many different but structurally-related
materials. A key problem in materials discovery, the phase map identification
problem, involves the determination of the crystal phase diagram from the
materials' composition and structural characterization data. We present
Phase-Mapper, a novel AI platform to solve the phase map identification problem
that allows humans to interact with both the data and products of AI
algorithms, including the incorporation of human feedback to constrain or
initialize solutions. Phase-Mapper affords incorporation of any spectral
demixing algorithm, including our novel solver, AgileFD, which is based on a
convolutive non-negative matrix factorization algorithm. AgileFD can
incorporate constraints to capture the physics of the materials as well as
human feedback. We compare three solver variants with previously proposed
methods in a large-scale experiment involving 20 synthetic systems,
demonstrating the efficacy of imposing physical constrains using AgileFD.
Phase-Mapper has also been used by materials scientists to solve a wide variety
of phase diagrams, including the previously unsolved Nb-Mn-V oxide system,
which is provided here as an illustrative example.


title:
How the instability of ranks under long memory affects large-sample
  inference

abstract:
  Under long memory, the limit theorems for normalized sums of random variables
typically involve a positive integer called "Hermite rank". There is a
different limit for each Hermite rank. From a statistical point of view,
however, we argue that a rank other than one is unstable, whereas, a rank equal
to one is stable. We provide empirical evidence supporting this argument. This
has important consequences. Assuming a higher-order rank when it is not really
there usually results in underestimating the order of the fluctuations of the
statistic of interest. We illustrate this through various examples involving
the sample variance, the empirical processes and the Whittle estimator.


title: Signatures of metal-free star formation in Planck 2015 Polarization Data

abstract:
  Standard analyses of the reionization history of the universe from Planck
cosmic microwave background (CMB) polarization measurements consider only the
overall optical depth to electron scattering ($\tau$), and further assume a
step-like reionization history. However, the polarization data contain
information beyond the overall optical depth, and the assumption of a step-like
function may miss high redshift contributions to the optical depth and lead to
biased $\tau$ constraints. Accounting for its full reionization information
content, we reconsider the interpretation of Planck 2015 Low Frequency
Instrument (LFI) polarization data using simple, yet physically-motivated
reionization models. We show that these measurements still, in fact, allow a
non-negligible contribution from metal-free (Pop-III) stars forming in
mini-halos of mass $M \sim 10^5-10^6 M_\odot$ at $z \gtrsim 15$, provided this
mode of star formation is fairly inefficient. Our best fit model includes an
early, self-regulated phase of Pop-III star formation in which the reionization
history has a gradual, plateau feature. In this model, $\sim$20\% of the volume
of the universe is ionized by $z \sim 20$, yet it nevertheless provides a good
match to the Planck LFI measurements. Although preferred when the full
information content of the data is incorporated, this model would spuriously be
disfavored in the standard analysis. This preference is driven mostly by excess
power from E-mode polarization at multipoles of $10 \lesssim \ell \lesssim 20$,
which may reflect remaining systematic errors in the data, a statistical
fluctuation, or signatures of the first stars. Measurements from the Planck
High Frequency Instrument (HFI) should be able to confirm or refute this hint
and future cosmic-variance limited E-mode polarization surveys can provide
substantially more information on these signatures


title: Diagonal-preserving gauge-invariant isomorphisms of graph $C^*$-algebras

abstract:
  We study graph $C^*$-algebras equipped with generalised gauge actions, and
characterise in terms of groupoids and groupoid cocycles when two graph
$C^*$-algebras are isomorphic by a diagonal-preserving isomorphism that
intertwines the generalised gauge actions. We apply this characterisation to
show that two Cuntz-Krieger algebras are isomorphic by a diagonal-preserving
isomorphism that intertwines the gauge actions if and only if the corresponding
one-sided subshifts are eventually conjugate, and that the stabilisation of two
Cuntz-Krieger algebras are isomorphic by a diagonal-preserving isomorphism that
intertwines the gauge actions if and only if the corresponding two-sided
subshifts are conjugate.


title:
Computation and validation of two-dimensional PSF simulation based on
  physical optics

abstract:
  The Point Spread Function (PSF) is a key figure of merit for specifying the
angular resolution of optical systems and, as the demand for higher and higher
angular resolution increases, the problem of surface finishing must be taken
seriously even in optical telescopes. From the optical design of the
instrument, reliable ray-tracing routines allow computing and display of the
PSF based on geometrical optics. However, such an approach does not directly
account for the scattering caused by surface microroughness, which is
interferential in nature. Although the scattering effect can be separately
modeled, its inclusion in the ray-tracing routine requires assumptions that are
difficult to verify. In that context, a purely physical optics approach is more
appropriate as it remains valid regardless of the shape and size of the defects
appearing on the optical surface. Such a computation, when performed in
two-dimensional consideration, is memory and time consuming because it requires
one to process a surface map with a few micron resolution, and the situation
becomes even more complicated in case of optical systems characterized by more
than one reflection. Fortunately, the computation is significantly simplified
in far-field configuration, since the computation involves only a sequence of
Fourier Transforms. In this paper, we provide validation of the PSF simulation
with Physical Optics approach through comparison with real PSF measurement data
in the case of ASTRI-SST M1 hexagonal segments. These results represent a first
foundation stone for future development in a more advanced computation taking
into account microroughness and multiple reflection in optical systems.


title:
Effects of Orthogonal Rotating Electric Fields on Electrospinning
  Process

abstract:
  Electrospinning is a nanotechnology process whereby an external electric
field is used to accelerate and stretch a charged polymer jet, so as to produce
fibers with nanoscale diameters. In quest of a further reduction in the cross
section of electrified jets hence of a better control on the morphology of the
resulting electrospun fibers, we explore the effects of an external rotating
electric field orthogonal to the jet direction. Through extensive particle
simulations, it is shown that by a proper tuning of the electric field
amplitude and frequency, a reduction of up to a $30 \%$ in the aforementioned
radius can be obtained, thereby opening new perspectives in the design of
future ultra-thin electrospun fibres. Applications can be envisaged in the
fields of nanophotonic components as well as for designing new and improved
filtration materials.


title:
Ground State of the Two Orbital Hubbard Model on the Pyrochlore Lattice
  with Competing Double Exchange and Superexchange Interactions

abstract:
  The two orbital Hubbard model, with the electrons additionally coupled to a
complex magnetic background, arises in the pyrochlore molybdates. The
background involves local moments Hund's coupled to the electrons, driving
double exchange ferromagnetism, and antiferromagnetic tendency arising from
competing superexchange. The key scales include the Hubbard repulsion and the
superexchange, both of which can be tuned in these materials, controlling phase
transitions from a ferromagnetic metal to a spin glass metal and then a spin
glass (Mott) insulator. We provide a comprehensive description of the ground
state of this model using an unrestricted Hartree-Fock scheme implemented via a
simulated annealing procedure. We establish the metal-insulator transition line
for varying Hubbard interaction and superexchange. The orbital disorder already
present in the ferromagnetic case is further enhanced by antiferromagnetic
coupling and the resulting magnetic disorder. This suppresses the kinetic
energy and shifts the metal-insulator transition to lower Hubbard interaction.
We characterise the changing nature of the metal-insulator transition by
tracking the magnetic and orbital correlations, the density of states, and the
optical conductivity. The metal-insulator transition shows increasing
'Anderson' character as the antiferromagnetic coupling is increased. This paper
is focused on the ground state, a companion paper will discuss the finite
temperature physics involving magnetic and orbital thermal fluctuations.


title: Deep Visual Foresight for Planning Robot Motion

abstract:
  A key challenge in scaling up robot learning to many skills and environments
is removing the need for human supervision, so that robots can collect their
own data and improve their own performance without being limited by the cost of
requesting human feedback. Model-based reinforcement learning holds the promise
of enabling an agent to learn to predict the effects of its actions, which
could provide flexible predictive models for a wide range of tasks and
environments, without detailed human supervision. We develop a method for
combining deep action-conditioned video prediction models with model-predictive
control that uses entirely unlabeled training data. Our approach does not
require a calibrated camera, an instrumented training set-up, nor precise
sensing and actuation. Our results show that our method enables a real robot to
perform nonprehensile manipulation -- pushing objects -- and can handle novel
objects not seen during training.


title:
A Note On The Semiclassical Formulation Of BPS States In
  Four-Dimensional N=2 Theories

abstract:
  Vector spaces of (framed) BPS states of Lagrangian four-dimensional N=2 field
theories can be defined in semiclassical chambers in terms of the
$L^2$-cohomology of Dirac-like operators on monopole moduli spaces. This was
spelled out previously for theories with only vectormultiplets, taking into
account only a subset of the possible half-supersymmetric 't Hooft-Wilson line
defects. This note completes the discussion by describing the modifications
needed when including matter hypermultiplets together with arbitrary 't
Hooft-Wilson line defects. Two applications of this extended discussion are
given.


title: A Study on Set-Valuations of Signed Graphs

abstract:
  Let $X$ be a non-empty ground set and $\mathcal{P}(X)$ be its power set. A
set-labeling (or a set-valuation) of a graph $G$ is an injective set-valued
function $f:V(G)\to \mathcal{P}(X)$ such that the induced function
$f^\oplus:E(G) \to \mathcal{P}(X)$ is defined by $f^\oplus(uv) = f(u)\oplus
f(v)$, where $f(u)\oplus f(v)$ is the symmetric difference of the sets $f(u)$
and $f(v)$. A graph which admits a set-labeling is known to be a set-labeled
graph. A set-labeling $f$ of a graph $G$ is said to be a set-indexer of $G$ if
the associated function $f^\oplus$ is also injective. In this paper, we define
the notion of set-valuations of signed graphs and discuss certain properties of
signed graphs which admits certain types of set-valuations.


title: Antideuterons in cosmic rays: sources and discovery potential

abstract:
  Antibaryons are produced in our Galaxy in collisions of high energy cosmic
rays with the interstellar medium and in old supernova remnants, and possibly,
in exotic sources such as primordial black hole evaporation or dark matter
annihilations and decays. The search for signals from exotic sources in
antiproton data is hampered by large backgrounds from spallation which, within
theoretical errors, can solely account for the current data. Due to the higher
energy threshold for antideuteron production, which translates into a
suppression of the low energy flux from spallations, antideuteron searches have
been proposed as a probe for exotic sources. We perform in this paper a
comprehensive analysis of the antideuteron fluxes at the Earth expected from
known and hypothetical sources in our Galaxy, and we calculate their maximal
values consistent with current antiproton data from AMS-02. We find that
supernova remnants generate a negligible flux, whereas primordial black hole
evaporation and dark matter annihilations or decays may dominate the total flux
at low energies. On the other hand, we find that the detection of cosmic
antideuterons would require, for the scenarios studied in this paper and
assuming optimistic values of the coalescence momentum and solar modulation, an
increase of the experimental sensitivity compared to ongoing and planned
instruments by at least a factor of 2. Finally, we briefly comment on the
prospects for antihelium-3 detection.


title:
Footstep and Motion Planning in Semi-unstructured Environments Using
  Randomized Possibility Graphs

abstract:
  Traversing environments with arbitrary obstacles poses significant challenges
for bipedal robots. In some cases, whole body motions may be necessary to
maneuver around an obstacle, but most existing footstep planners can only
select from a discrete set of predetermined footstep actions; they are unable
to utilize the continuum of whole body motion that is truly available to the
robot platform. Existing motion planners that can utilize whole body motion
tend to struggle with the complexity of large-scale problems. We introduce a
planning method, called the "Randomized Possibility Graph", which uses
high-level approximations of constraint manifolds to rapidly explore the
"possibility" of actions, thereby allowing lower-level motion planners to be
utilized more efficiently. We demonstrate simulations of the method working in
a variety of semi-unstructured environments. In this context,
"semi-unstructured" means the walkable terrain is flat and even, but there are
arbitrary 3D obstacles throughout the environment which may need to be stepped
over or maneuvered around using whole body motions.


title:
Traversing Environments Using Possibility Graphs with Multiple Action
  Types

abstract:
  Locomotion for legged robots poses considerable challenges when confronted by
obstacles and adverse environments. Footstep planners are typically only
designed for one mode of locomotion, but traversing unfavorable environments
may require several forms of locomotion to be sequenced together, such as
walking, crawling, and jumping. Multi-modal motion planners can be used to
address some of these problems, but existing implementations tend to be
time-consuming and are limited to quasi-static actions. This paper presents a
motion planning method to traverse complex environments using multiple
categories of continuous actions. To this end, this paper formulates and
exploits the Possibility Graph---which uses high-level approximations of
constraint manifolds to rapidly explore the "possibility" of actions---to
utilize lower-level single-action motion planners more effectively. We show
that the Possibility Graph can quickly find routes through several different
challenging environments which require various combinations of actions in order
to traverse.


title: A note on a characterization theorem for a certain class of domains

abstract:
  We have introduced and studied in [3] the class of Globalized
multiplicatively pinched-Dedekind domains (GMPD domains). This class of domains
could be characterized by a certain factorization property of the
non-invertible ideals, (see [3, Theorem 4]). In this note a simplification of
the characterization theorem [3, Theorem 4] is provided in more general form.


title: Space nutrition: the key role of nutrition in human space flight

abstract:
  From the basic impact of nutrient intake on health maintenance to the
psychosocial benefits of mealtime, great advancements in nutritional sciences
for support of human space travel have occurred over the past 60 years.
Nutrition in space has many areas of impact, including provision of required
nutrients and maintenance of endocrine, immune, and musculoskeletal systems. It
is affected by environmental conditions such as radiation, temperature, and
atmospheric pressures, and these are reviewed. Nutrition with respect to space
flight is closely interconnected with other life sciences research disciplines
including the study of hematology, immunology, as well as neurosensory,
cardiovascular, gastrointestinal, circadian rhythms, and musculoskeletal
physiology. Psychosocial aspects of nutrition are also important for more
productive missions and crew morale. Research conducted to determine the impact
of spaceflight on human physiology and subsequent nutritional requirements will
also have direct and indirect applications in Earth-based nutrition research.
Cumulative nutritional research over the past five decades has resulted in the
current nutritional requirements for astronauts. Realization of the full role
of nutrition during spaceflight is critical for the success of
extended-duration missions. Long-duration missions will require quantitation of
nutrient requirements for maintenance of health and protection against the
effects of microgravity.
  Keywords: Space nutrition, space flight, effects of microgravity, astronauts,
space food


title:
A thermodynamic approach to nonlinear ultrasonics for material state
  awareness and prognosis

abstract:
  We develop a thermodynamic framework for modeling nonlinear ultrasonic damage
sensing and prognosis in materials undergoing progressive damage. The framework
is based on the internal variable approach and relies on the construction of a
pseudo-elastic strain energy function that captures the energetics associated
with the damage progression. The pseudo-elastic strain energy function is
composed of two energy functions - one that describes how a material stores
energy in an elastic fashion and the other describes how material dissipates
energy or stores it in an inelastic fashion. Experimental motivation for the
choice of the above two functionals is discussed and some specific choices
pertaining to damage progression during fatigue and creep are presented. The
thermodynamic framework is employed to model the nonlinear response of material
undergoing stress relaxation and creep-like degradation. For each of the above
cases, evolution of the nonlinearity parameter with damage as well as with
macroscopic measurables like accumulated plastic strain are obtained.

categories: cs.CE cond-mat.mtrl-sci cond-mat.soft physics.comp-ph


title: The NEW detector: construction, commissioning and first results

abstract:
  NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta
(\beta\beta 0\nu) decay experiment at the Canfranc Underground Laboratory
(LSC). It seeks to detect the (\beta\beta 0\nu) decay of Xe-136 using a high
pressure xenon gas TPC with electroluminescent (EL) amplification. The
NEXT-White (NEW) detector, with an active xenon mass of about 10 kg at 15 bar,
is the first NEXT prototype installed at LSC. It implements the NEXT detector
concept tested in smaller prototypes using the same radiopure sensors and
materials that will be used in the future NEXT-100, serving as a benchmark for
technical solutions as well as for the signal selection and background
rejection algorithms. NEW is currently under commissioning at the LSC. In this
poster proceedings we describe the technical solutions adopted for NEW
construction, the lessons learned from the commissioning phase, and the first
results on energy calibration and energy resolution obtained with low-energy
radioactive source data.


title: Measurement of neutrino interactions in gaseous argon with T2K

abstract:
  The T2K near-detector, ND280, employs three large argon gas TPCs (Time
Projection Chambers) for particle tracking and identification. The gas inside
the TPCs can be used as an active target to study the neutrino interactions in
great detail. The low density of the gas leads to very low track energy
thresholds, allowing the reconstruction of very low momentum tracks, e.g.
protons with kinetic energies down to $\mathcal{O}$(1 MeV). Since different
nuclear interaction models vary considerably in their predictions of those low
momentum track multiplicities, this makes neutrino interactions on gases a
powerful probe to test those models. The TPCs operate with an argon-based gas
mixture (95% by volume) and have been exposed to the T2K neutrino beam since
the beginning of the experiment in 2010. Due to the low total mass of the gas,
neutrino argon interactions happen only rarely, compared to the surrounding
scintillator-based detectors. We expect about 600 such events in the recorded
data so far (about 200 in the fiducial volume). We are able to separate those
events from the background and thus demonstrate the viability of using gaseous
argon as a target for a neutrino beam. This enables us to do a cross- section
measurement on gaseous argon, the first measurement of this kind. All previous
neutrino cross-section measurements on argon were performed in liquid argon
TPCs.


title:
Heterotic sigma models on $T^8$ and the Borcherds automorphic form
  $\Phi_{12}$

abstract:
  We consider the spectrum of BPS states of the heterotic sigma model with
$(0,8)$ supersymmetry and $T^8$ target, as well as its second-quantized
counterpart. We show that the counting function for such states is intimately
related to Borcherds' automorphic form $\Phi_{12}$, a modular form which
exhibits automorphy for $O(2,26;{\mathbb Z})$. We comment on possible
implications for Umbral moonshine and theories of AdS$_3$ gravity.


title:
An observer's guide to the (Local Group) dwarf galaxies: predictions for
  their own dwarf satellite populations

abstract:
  A recent surge in the discovery of new ultrafaint dwarf satellites of the
Milky Way has inspired the idea of searching for faint satellites, $10^3\,
\mathrm{M_{\odot}} < M_* < 10^6\, \mathrm{M_{\odot}}$, around less massive
field galaxies in the Local Group. Such satellites would be subject to weaker
environmental influences than Milky Way satellites, and could lead to new
insights on low mass galaxy formation. In this paper, we predict the number of
luminous satellites expected around field dwarf galaxies by applying several
abundance matching models and a reionization model to the dark-matter only
\textit{Caterpillar} simulation suite. For three of the four abundance matching
models used, we find a $>99\%$ chance that at least one satellite with stellar
mass $M_*> 10^5\, \mathrm{M_{\odot}}$ exists around the combined five Local
Group field dwarf galaxies with the largest stellar mass. When considering
satellites with $M_*> 10^4\, \mathrm{M_{\odot}}$, we predict a combined $5-25$
satellites for the five largest field dwarfs, and $10-50$ for the whole Local
Group field dwarf population. Because of the relatively small number of
predicted dwarfs, and their extended spatial distribution, a large fraction
each Local Group dwarf's virial volume will need to be surveyed to guarantee
discoveries. We compute the predicted number of satellites in a given field of
view of specific Local Group galaxies, as a function of minimum satellite
luminosity, and explicitly obtain such values for the Solitary Local dwarfs
survey. Uncertainties in abundance matching and reionization models are large,
implying that comprehensive searches could lead to refinements of both models.


title: Semi-synthetic zigzag optical lattice for ultracold bosons

abstract:
  We consider a one-dimensional "zigzag" lattice, pictured as a two-site wide
single strip taken from a triangular lattice, affected by a tunable homogeneous
magnetic flux piercing its triangular plaquettes. We focus on a semi-synthetic
lattice produced by combining a one-dimensional spin-dependent lattice in the
long direction with laser-induced transitions between atomic internal states
that define the short synthetic dimension. In contrast to previous studies on
semi-synthetic lattices, the atom-atom interactions are nonlocal in both
lattice directions. We investigate the ground-state properties of the system
for the case of strongly interacting bosons, and find that the interplay
between the frustration induced by the magnetic field and the interactions
gives rise to an exotic gapped phase at fractional filling factors
corresponding to one particle per magnetic unit cell.


title: Covariant diagrams for one-loop matching

abstract:
  We present a diagrammatic formulation of recently-revived covariant
functional approaches to one-loop matching from an ultraviolet (UV) theory to a
low-energy effective field theory. Various terms following from a covariant
derivative expansion (CDE) are represented by diagrams which, unlike
conventional Feynman diagrams, involve gauge-covariant quantities and are thus
dubbed "covariant diagrams." The use of covariant diagrams helps organize and
simplify one-loop matching calculations, which we illustrate with examples. Of
particular interest is the derivation of UV model-independent universal
results, which reduce matching calculations of specific UV models to
applications of master formulas. We show how such derivation can be done in a
more concise manner than the previous literature, and discuss how additional
structures that are not directly captured by existing universal results,
including mixed heavy-light loops, open covariant derivatives, and mixed
statistics, can be easily accounted for.


title:
Diffuse gamma-ray emission from the Galactic center and implications of
  its past activities

abstract:
  It has been indicated that low-luminosity active galactic nuclei (LLAGNs) are
accelerating high-energy cosmic-ray (CR) protons in their radiatively
inefficient accretion flows (RIAFs). If this is the case, Sagittarius A* (Sgr
A*) should also be generating CR protons, because Sgr A* is a LLAGN. Based on
this scenario, we calculate a production rate of CR protons in Sgr A* and their
diffusion in the central molecular zone (CMZ) around Sgr A*. The CR protons
diffusing in the CMZ create gamma-rays through pp interaction. We show that the
gamma-ray luminosity and spectrum are consistent with observations if Sgr A*
was active in the past.


title:
GALEX-SDSS-WISE Legacy Catalog (GSWLC): Star Formation Rates, Stellar
  Masses and Dust Attenuations of 700,000 Low-redshift Galaxies

abstract:
  In this paper, we present GALEX-SDSS-WISE Legacy Catalog (GSWLC), a catalog
of physical properties (stellar masses, dust attenuations and star formation
rates (SFRs)) of ~700,000 galaxies with SDSS redshifts below 0.3. GSWLC
contains galaxies within the GALEX footprint, regardless of a UV detection,
covering 90% of SDSS. The physical properties were obtained from UV/optical SED
fitting following Bayesian methodology of Salim et al. (2007), with
improvements such as blending corrections for low-resolution UV photometry,
flexible dust attenuation laws, and emission line corrections. GSWLC includes
mid-IR SFRs derived from IR templates based upon 22 micron WISE observations.
These estimates are independent of UV/optical SED fitting, in order to separate
possible systematics. The paper argues that the comparison of specific SFRs
(SSFRs) is more informative and physically motivated than the comparison of
SFRs. SSFRs resulting from the UV/optical SED fitting are compared to the
mid-IR SSFRs, and to SSFRs from three published catalogs. For "main sequence"
galaxies with no AGN contribution all SSFRs are in very good agreement (within
0.1 dex on average). In particular, the widely-used aperture-corrected SFRs
from MPA/JHU catalog show no systematic offsets, in contrast to some
integral-field spectroscopy results. For galaxies below the main sequence (log
SSFR<-11), mid-IR (S)SFRs based on fixed luminosity-SFR conversion are severely
biased (up to 2 dex) because the dust is primarily heated by old stars.
Furthermore, mid-IR (S)SFRs are overestimated by up to 0.6 dex for galaxies
with AGN, presumably due to non-stellar dust heating. UV/optical (S)SFRs are
thus preferred to IR-based (S)SFRs for quenched galaxies and those which host
AGN.


title:
The candidate cluster and protocluster catalog (CCPC) II:
  Spectroscopically identified structures spanning 2 < z < 6.6

abstract:
  The Candidate Cluster and Protocluster Catalog (CCPC) is a list of objects at
redshifts z > 2 composed of galaxies with spectroscopically confirmed redshifts
that are coincident on the sky and in redshift. These protoclusters are
identified by searching for groups in volumes corresponding to the expected
size of the most massive protoclusters at these redshifts. In CCPC1 we
identified 43 candidate protoclusters among 14,000 galaxies between 2.74 < z <
3.71. Here we expand our search to more than 40,000 galaxies with spectroscopic
redshifts z > 2.00, resulting in an additional 173 candidate structures. The
most significant of these are 36 protoclusters with overdensities {\delta} > 7.
We also identify three large proto-supercluster candidates containing multiple
protoclusters at z = 2.3, 3.5 and z = 6.56. Eight candidates with N > 10 or
more galaxies are found at redshifts z > 4.0. The last system in the catalog is
the most distant spectroscopic protocluster candidate known to date at z =
6.56.


title:
How to design a planetary system for different scattering outcomes:
  giant impact sweet spot, maximising exocomets, scattered disks

abstract:
  This paper considers the dynamics of scattering of planetesimals or planetary
embryos by a planet on a circumstellar orbit. We classify six regions in the
planet's mass versus semimajor axis parameter space according to the dominant
outcome for scattered objects: ejected, accreted, remaining, escaping, Oort
Cloud, depleted Oort Cloud. We use these outcomes to consider which planetary
system architectures maximise the observability of specific signatures, given
that signatures should be detected first around systems with optimal
architectures (if such systems exist in nature). Giant impact debris is most
readily detectable for 0.1-10Mearth planets at 1-5au, depending on detection
method and spectral type. While A stars have putative giant impact debris at
4-6au consistent with this sweet spot, that of FGK stars is typically <<1au
contrary to expectations; an absence of 1-3au giant impact debris could
indicate a low frequency of terrestrial planets there. Three principles
maximise cometary influx from exo-Kuiper belts: a chain of closely separated
planets interior to the belt, none of which is a Jupiter-like ejector; planet
masses not increasing strongly with distance (for a net inward torque on
comets); ongoing replenishment of comets, possibly by embedded low-mass
planets. A high Oort Cloud comet influx requires no ejector and architectures
that maximise the Oort Cloud population. Cold debris disks are usually
considered classical Kuiper belt analogues. Here we consider the possibility of
detecting scattered disk analogues, which could be betrayed by a broad radial
profile and lack of small grains, as well as spherical 100-1000au mini-Oort
Clouds. Some implications for escaping planets around young stars, detached
planets akin to Sedna, and the formation of super-Earths, are also discussed.


title:
The Coupled Physical Structure of Gas and Dust in the IM Lup
  Protoplanetary Disk

abstract:
  The spatial distribution of gas and solids in protoplanetary disks determines
the composition and formation efficiency of planetary systems. A number of
disks show starkly different distributions for the gas and small grains
compared to millimeter-centimeter sized dust. We present new Atacama Large
Millimeter/Submillimeter Array (ALMA) observations of the dust continuum, CO,
$^{13}$CO, and C$^{18}$O in the IM Lup protoplanetary disk, one of the first
systems where this dust-gas dichotomy was clearly seen. The $^{12}$CO is
detected out to a radius of 970 AU, while the millimeter continuum emission is
truncated at just 313 AU. Based upon this data, we have built a comprehensive
physical and chemical model for the disk structure, which takes into account
the complex, coupled nature of the gas and dust and the interplay between the
local and external environment. We constrain the distributions of gas and dust,
the gas temperatures, the CO abundances, the CO optical depths, and the
incident external radiation field. We find that the reduction/removal of dust
from the outer disk exposes this region to higher stellar and external
radiation and decreases the rate of freeze-out, allowing CO to remain in the
gas out to large radial distances. We estimate a gas-phase CO abundance of
$5\%$ of the ISM value and a low external radiation field ($G_0\lesssim4$). The
latter is consistent with that expected from the local stellar population. We
additionally find tentative evidence for ring-like continuum substructure,
suggestions of isotope-selective photodissociation, and a diffuse gas halo.


title:
Molecular Gas Along a Bright H-alpha Filament in 2A 0335+096 Revealed by
  ALMA

abstract:
  We present ALMA CO(1-0) and CO(3-2) observations of the brightest cluster
galaxy (BCG) in the 2A 0335+096 galaxy cluster (z = 0.0346). The total
molecular gas mass of (1.13+/-0.15) x 10^9 M_sun is divided into two
components: a nuclear region and a 7 kpc long dusty filament. The central
molecular gas component accounts for (3.2+/-0.4) x 10^8 M_sun of the total
supply of cold gas. Instead of forming a rotationally-supported ring or disk,
it is composed of two distinct, blueshifted clumps south of the nucleus and a
series of low-significance redshifted clumps extending toward a nearby
companion galaxy. The velocity of the redshifted clouds increases with radius
to a value consistent with the companion galaxy, suggesting that an interaction
between these galaxies <20 Myr ago disrupted a pre-existing molecular gas
reservoir within the BCG. Most of the molecular gas, (7.8+/-0.9) x 10^8 M_sun,
is located in the filament. The CO emission is co-spatial with a 10^4 K
emission-line nebula and soft X-rays from 0.5 keV gas, indicating that the
molecular gas has cooled out of the intracluster medium over a period of 25-100
Myr. The filament trails an X-ray cavity, suggesting that the gas has cooled
from low entropy gas that has been lifted out of the cluster core and become
thermally unstable. We are unable to distinguish between inflow and outflow
along the filament with the present data. Cloud velocities along the filament
are consistent with gravitational free-fall near the plane of the sky, although
their increasing blueshifts with radius are consistent with outflow.


title: On radiative acceleration in spine-sheath structured blazar jets

abstract:
  It has been proposed that blazar jets are structured, with a fast spine
surrounded by a slower sheath or layer. This structured jet model explains some
properties of their emission and morphology. Because of their relative motion,
the radiation produced by one component is seen amplified by the other, thus
enhancing the inverse Compton emission of both. Radiation is emitted
anisotropically in the comoving frames, and causes the emitting plasma to
recoil. As seen in the observer frame, this corresponds to a deceleration of
the fastest component (the spine) and an acceleration of the slower one (the
layer). While the deceleration of the spine has already been investigated, here
we study for the first time the acceleration of the sheath and find
self-consistent velocity profile solutions for both the spine and the sheath
while accounting for radiative cooling. We find that the sheath can be
accelerated to the velocities required by the observations if its leptons
remain energetic in the acceleration region, assumed to be of the order of 100
Schwarzschild radii, demanding continuous injection of energetic particles in
that region.


title: From 6D SCFTs to Dynamic GLSMs

abstract:
  Compactifications of 6D superconformal field theories (SCFTs) on
four-manifolds generate a large class of novel 2d quantum field theories. We
consider in detail the case of the rank one simple non-Higgsable cluster 6D
SCFTs. On the tensor branch of these theories, the gauge group is simple and
there are no matter fields. For compactifications on suitably chosen Kahler
surfaces, we present evidence that this provides a method to realize 2d SCFTs
with N = (0,2) supersymmetry. In particular, we find that reduction on the
tensor branch of the 6D SCFT yields a description of the same 2d fixed point
that is described in the UV by a gauged linear sigma model (GLSM) in which the
parameters are promoted to dynamical fields, that is, a "dynamic GLSM" (DGLSM).
Consistency of the model requires the DGLSM to be coupled to additional
non-Lagrangian sectors obtained from reduction of the anti-chiral two-form of
the 6D theory. These extra sectors include both chiral and anti-chiral
currents, as well as spacetime filling non-critical strings of the 6D theory.
For each candidate 2d SCFT, we also extract the left- and right-moving central
charges in terms of data of the 6D SCFT and the compactification manifold.


title: Clues to the origin of Fermi Bubbles from OVIII/OVII line ratio

abstract:
  We constrain the origin of Fermi Bubbles using 2D hydrodynamical simulations
of both star formation driven and black hole accretion driven wind models. We
compare our results with recent observations of OVIII to OVII line ratio within
and near Fermi Bubbles. Our results suggest that independent of the driving
mechanisms, a low luminosity ($\mathcal{L} \sim 0.7-1\times 10^{41}$ erg
s$^{-1}$) energy injection best reproduces the observed line ratio for which
the shock temperature is $\approx 3\times 10^6$ K. Assuming the Galactic halo
temperature to be $2\times 10^6$K, we estimate the shock velocity to be $\sim
300$ km s$^{-1}$ for a weak shock. The corresponding estimated age of the Fermi
bubbles is $\sim 15-25$ Myr. Such an event can be produced either by a star
formation rate of $\sim 0.5$ M$_\odot$ yr$^{-1}$ at the Galactic centre or a
very low luminosity jet/accretion wind arising from the central black hole. Our
analysis rules out any activity that generates an average mechanical luminosity
$\gtrsim 10^{41}$ \ergps as a possible origin of the Fermi Bubbles.


title: Introduction to Focus Issue: Patterns of Network Synchronization

abstract:
  The study of synchronization of coupled systems is currently undergoing a
major surge fueled by recent discoveries of new forms of collective dynamics
and the development of techniques to characterize a myriad of new patterns of
network synchronization. This includes chimera states, phenomena determined by
symmetry, remote synchronization, and asymmetry-induced synchronization. This
Focus Issue presents a selection of contributions at the forefront of these
developments, to which this introduction is intended to offer an up-to-date
foundation.

categories: cond-mat.dis-nn nlin.CD nlin.PS physics.soc-ph


title: KOI-1003: A new spotted, eclipsing RS CVn binary in the Kepler field

abstract:
  Using the high-precision photometry from the Kepler space telescope,
thousands of stars with stellar and planetary companions have been observed.
The characterization of stars with companions is not always straightforward and
can be contaminated by systematic and stellar influences on the light curves.
Here, through a detailed analysis of starspots and eclipses, we identify
KOI-1003 as a new, active RS CVn star---the first identified with data from
Kepler. The Kepler light curve of this close binary system exhibits the
system's primary transit, secondary eclipse, and starspot evolution of two
persistent active longitudes. The near equality of the system's orbital and
rotation periods indicates the orbit and primary star's rotation are nearly
synchronized ($P_\mathrm{orb} = 8.360613\pm0.000003$ days; $P_\mathrm{rot} \sim
8.23$ days). By assuming the secondary star is on the main sequence, we suggest
the system consists of a $1.45^{+0.11}_{-0.19} \ M_\odot$ subgiant primary and
a $0.59^{+0.03}_{-0.04} \ M_\odot$ main-sequence companion. Our work gives a
distance of $4400 \pm 600$ pc and an age of $t = 3.0^{-0.5}_{+2.0}$ Gyr,
parameters which are discrepant with previous studies that included the star as
a member of the open cluster NGC 6791.


title: Linear spectropolarimetry of polarimetric standard stars with VLT/FORS2

abstract:
  We reduced ESO's archival linear spectropolarimetry data (4000-9000\AA) of 6
highly polarized and 8 unpolarized standard stars observed between 2010 and
2016, for a total of 70 epochs, with the FOcal Reducer and low dispersion
Spectrograph (FORS2) mounted at the Very Large Telescope. We provide very
accurate standard stars polarization measurements as a function of wavelength,
and test the performance of the spectropolarimetric mode (PMOS) of FORS2. We
used the unpolarized stars to test the time stability of the PMOS mode, and
found a small ($\leq$0.1%), but statistically significant, on-axis instrumental
polarization wavelength dependency, possibly caused by the tilted surfaces of
the dispersive element. The polarization degree and angle are found to be
stable at the level of $\leq$0.1% and $\leq$0.2 degrees, respectively. We
derived the polarization wavelength dependence of the polarized standard stars
and found that, in general, the results are consistent with those reported in
the literature, e.g. Fossati et al. (2007) who performed a similar analysis
using FORS1 data. The re-calibrated data provide a very accurate set of
standards that can be very reliably used for technical and scientific purposes.
The analysis of the Serkowski parameters revealed a systematic deviation from
the width parameter $K$ reported by Whittet et al. (1992). This is most likely
explained by incorrect effective wavelengths adopted in that study for the R
and I bands.


title: Roughness tolerances for Cherenkov telescope mirrors

abstract:
  The Cherenkov Telescope Array (CTA) is a forthcoming international
ground-based observatory for very high-energy gamma rays. Its goal is to reach
sensitivity five to ten times better than existing Cherenkov telescopes such as
VERITAS, H.E.S.S. or MAGIC and extend the range of observation to energies down
to few tens of GeV and beyond 100 TeV. To achieve this goal, an array of about
100 telescopes is required, meaning a total reflective surface of several
thousands of square meters. Thence, the optimal technology used for CTA mirrors
manufacture should be both low-cost (~1000 euros/m2) and allow high optical
performances over the 300-550 nm wavelength range. More exactly, a reflectivity
higher than 85% and a PSF (Point Spread Function) diameter smaller than 1 mrad.
Surface roughness can significantly contribute to PSF broadening and limit
telescope performances. Fortunately, manufacturing techniques for mirrors are
now available to keep the optical scattering well below the
geometrically-predictable effect of figure errors. This paper determines first
order surface finish tolerances based on a surface microroughness
characterization campaign, using Phase Shift Interferometry. That allows us to
compute the roughness contribution to Cherenkov telescope PSF. This study is
performed for diverse mirror candidates (MAGIC-I and II, ASTRI, MST) varying in
manufacture technologies, selected coating materials and taking into account
the degradation over time due to environmental hazards.


title:
The Two-Parameter Brane Sigma-Model: M*, M' solutions and M-theory
  solutions dependent on exotic coordinates

abstract:
  We investigate two-parameter solutions of sigma-models on two dimensional
symmetric spaces contained in E11. Embedding such sigma-model solutions in
space-time gives solutions of M* and M'-theory where the metric depends on
general travelling wave functions, as opposed to harmonic functions typical in
general relativity, supergravity and M-theory. Weyl reflection allows such
solutions to be mapped to M-theory solutions where the wave functions depend
explicitly on extra coordinates contained in the fundamental representation of
E11.


title:
High Quality Factor Platinum Silicide Microwave Kinetic Inductance
  Detectors

abstract:
  We report on the development of Microwave Kinetic Inductance Detectors
(MKIDs) using platinum silicide as the sensor material. MKIDs are an emerging
superconducting detector technology, capable of measuring the arrival times of
single photons to better than two microseconds and their energies to around ten
percent. Previously, MKIDs have been fabricated using either sub-stoichiometric
titanium nitride or aluminum, but TiN suffers from spatial inhomogeneities in
the superconducting critical temperature and Al has a low kinetic inductance
fraction, causing low detector sensitivity. To address these issues, we have
instead fabricated PtSi microresonators with superconducting critical
temperatures of 944$\pm$12~mK and high internal quality factors ($Q_i \gtrsim
10^6$). These devices show typical quasiparticle lifetimes of $\tau_{qp}
\approx 30$--$40~\mu$s and spectral resolution, $R = \lambda / \Delta \lambda$,
of 8 at 406.6~nm. We compare PtSi MKIDs to those fabricated with TiN and detail
the substantial advantages that PtSi MKIDs have to offer.


title:
Generation and protection of Maximally Entangled State between many
  modes in an optical network with dissipation

abstract:
  We present a three-cavity network model with two modes in each cavity and a
non-linear medium that generates a Kerr type interaction via both self-phase
and cross-phase modulation processes. We have two main goals. The first one is
to generate a multipartite Maximally Entangled State (MES), starting from the
ground state of the system. We address the problem both without and with
dissipation. Secondly, we want to protect the MES from decoherence. While
studying the MES, we analyze different bipartite and multipartite entanglement
measures. We also study the effect of an Avoided Level Crossing (ALC)
identified by the critical behavior of the entanglement measures, thus showing
that the quantum correlations act as a witness for such phenomena. Our findings
provide the quantum tools to perform the operation of generation and protection
of a maximally entangled state in a cavity QED environment.


title: Modifications to Holographic Entanglement Entropy in Warped CFT

abstract:
  In arXiv:1601.02634 it was observed that asymptotic boundary conditions play
an important role in the study of holographic entanglement beyond AdS/CFT. In
particular, the Ryu-Takayanagi proposal must be modified for warped AdS$_3$
(WAdS$_3$) with Dirichlet boundary conditions. In this paper, we consider
AdS$_3$ and WAdS$_3$ with Dirichlet-Neumann boundary conditions. The
conjectured holographic duals are warped conformal field theories (WCFTs),
featuring a Virasoro-Kac-Moody algebra. We provide a holographic calculation of
the entanglement entropy and R\'{e}nyi entropy using AdS$_3$/WCFT and
WAdS$_3$/WCFT dualities. Our bulk results are consistent with the WCFT results
derived by Castro-Hofman-Iqbal using the Rindler method. Comparing with
arXiv:1601.02634, we explicitly show that the holographic entanglement entropy
is indeed affected by boundary conditions. Both results differ from the
Ryu-Takayanagi proposal, indicating new relations between spacetime geometry
and quantum entanglement for holographic dualities beyond AdS/CFT.


title:
Complexity of Left-Ideal, Suffix-Closed and Suffix-Free Regular
  Languages

abstract:
  A language $L$ over an alphabet $\Sigma$ is suffix-convex if, for any words
$x,y,z\in\Sigma^*$, whenever $z$ and $xyz$ are in $L$, then so is $yz$.
Suffix-convex languages include three special cases: left-ideal, suffix-closed,
and suffix-free languages. We examine complexity properties of these three
special classes of suffix-convex regular languages. In particular, we study the
quotient/state complexity of boolean operations, product (concatenation), star,
and reversal on these languages, as well as the size of their syntactic
semigroups, and the quotient complexity of their atoms.


title: Material platforms for integrated quantum photonics

abstract:
  On-chip integration of quantum optical systems could be a major factor
enabling photonic quantum technologies. Unlike the case of electronics, where
the essential device is a transistor and the dominant material is silicon, the
toolbox of elementary devices required for both classical and quantum photonic
integrated circuits is vast. Therefore, many material platforms are being
examined to host the future quantum photonic computers and network nodes. We
discuss the pros and cons of several platforms for realizing various elementary
devices, compare the current degrees of integration achieved in each platform
and review several composite platform approaches.


title: Scale-invariant freezing of entanglement

abstract:
  We show that bipartite entanglement in a one-dimensional quantum spin model
undergoing time-evolution under local Markovian environments can be frozen over
time. We demonstrate this by using a number of paradigmatic quantum spin models
in one dimension, including the anisotropic XY model in the presence of a
uniform and an alternating transverse magnetic field (ATXY), the XXZ model, the
XYZ model, and the $J_1-J_2$ model involving the next-nearest-neighbor
interactions. We show that the length of the freezing interval, for a chosen
pair of nearest-neighbor spins, may remain independent of the length of the
spin-chain, for example, in paramagnetic phases of the ATXY model, indicating a
scale-invariance. Such freezing of entanglement is found to be robust against a
change in the environment temperature, presence of disorder in the system, and
whether the noise is dissipative, or not dissipative. Moreover, we connect the
freezing of entanglement with the propagation of information through a quantum
many-body system, as considered in the Lieb-Robinson theorem. We demonstrate
that the variation of the freezing duration exhibits a quadratic behavior
against the distance of the nearest-neighbor spin-pair from the noise-source,
obtained from exact numerical simulations, in contrast to the linear one as
predicted by the Lieb-Robinson theorem.


title:
Can Ground Truth Label Propagation from Video help Semantic
  Segmentation?

abstract:
  For state-of-the-art semantic segmentation task, training convolutional
neural networks (CNNs) requires dense pixelwise ground truth (GT) labeling,
which is expensive and involves extensive human effort. In this work, we study
the possibility of using auxiliary ground truth, so-called \textit{pseudo
ground truth} (PGT) to improve the performance. The PGT is obtained by
propagating the labels of a GT frame to its subsequent frames in the video
using a simple CRF-based, cue integration framework. Our main contribution is
to demonstrate the use of noisy PGT along with GT to improve the performance of
a CNN. We perform a systematic analysis to find the right kind of PGT that
needs to be added along with the GT for training a CNN. In this regard, we
explore three aspects of PGT which influence the learning of a CNN: i) the PGT
labeling has to be of good quality; ii) the PGT images have to be different
compared to the GT images; iii) the PGT has to be trusted differently than GT.
We conclude that PGT which is diverse from GT images and has good quality of
labeling can indeed help improve the performance of a CNN. Also, when PGT is
multiple folds larger than GT, weighing down the trust on PGT helps in
improving the accuracy. Finally, We show that using PGT along with GT, the
performance of Fully Convolutional Network (FCN) on Camvid data is increased by
$2.7\%$ on IoU accuracy. We believe such an approach can be used to train CNNs
for semantic video segmentation where sequentially labeled image frames are
needed. To this end, we provide recommendations for using PGT strategically for
semantic segmentation and hence bypass the need for extensive human efforts in
labeling.


title: Sequential Low-Rank Change Detection

abstract:
  Detecting emergence of a low-rank signal from high-dimensional data is an
important problem arising from many applications such as camera surveillance
and swarm monitoring using sensors. We consider a procedure based on the
largest eigenvalue of the sample covariance matrix over a sliding window to
detect the change. To achieve dimensionality reduction, we present a
sketching-based approach for rank change detection using the low-dimensional
linear sketches of the original high-dimensional observations. The premise is
that when the sketching matrix is a random Gaussian matrix, and the dimension
of the sketching vector is sufficiently large, the rank of sample covariance
matrix for these sketches equals the rank of the original sample covariance
matrix with high probability. Hence, we may be able to detect the low-rank
change using sample covariance matrices of the sketches without having to
recover the original covariance matrix. We character the performance of the
largest eigenvalue statistic in terms of the false-alarm-rate and the expected
detection delay, and present an efficient online implementation via subspace
tracking.


title: Capitulation, unit groups, and the cohomology of $S$-id\`{e}le classes

abstract:
  Let $L/K$ be a finite, cyclic extension of number fields with Galois group
$G$, and let $S$ be a finite set of primes of $K$ that includes all the
infinite primes. In this paper, we study the $G$-cohomology of the
$S$-id\`{e}le classes of $L$ and relate it to the $S$-capitulation map as well
as to the $G$-cohomology of the $S$-unit group $U_{L,S}$.