title:
Drell-Yan process in $pA$ collisions: the exact treatment of coherence
  effects

abstract:
  In this work, we investigate production of Drell-Yan (DY) pairs in
proton-nucleus collisions in kinematic regions where the corresponding
coherence length does not exceed the nuclear radius, $R_A$, and the quantum
coherence effects should be treated with a special care. The results for the
nucleus-to-nucleon production ratio available in the literature so far are
usually based on the assumption of a very long coherence length (LCL) $l_c\gg
R_A$. Since the onset of coherence effects is controlled by the coherence
length $l_c$, we estimated its magnitude in various kinematic regions of the DY
process and found that the LCL approximation should not be used at small and
medium c.m. collision energies ($\sqrt{s} \lesssim 200$ GeV) as well as at
large dilepton invariant masses. In order to obtain realistic predictions, we
computed for the first time the DY cross section using the generalised color
dipole approach based on the rigorous Green function formalism, which naturally
incorporates the color transparency and quantum coherence effects and hence
allows to estimate the nuclear shadowing with no restrictions on the CL. In
addition to the shadowing effect, we studied a complementary effect of initial
state interactions (ISI) that causes an additional suppression at large values
of the Feynman variable. Numerical results for the nuclear modification factor
accounting for the ISI effect and the finite $l_c$ are compared to the data
available from the fixed-target FNAL measurements and a good agreement has been
found. Besides, we present new predictions for the nuclear suppression as a
function of dilepton rapidity and invariant mass in the kinematic regions that
can be probed by the RHIC collider as well as by the planned AFTER@LHC and LHCb
fixed-target experiments.


title: Syntactically Informed Text Compression with Recurrent Neural Networks

abstract:
  We present a self-contained system for constructing natural language models
for use in text compression. Our system improves upon previous neural network
based models by utilizing recent advances in syntactic parsing -- Google's
SyntaxNet -- to augment character-level recurrent neural networks. RNNs have
proven exceptional in modeling sequence data such as text, as their
architecture allows for modeling of long-term contextual information.


title:
Temperature induced decay of persistent currents in a superfluid
  ultracold gas

abstract:
  We study how temperature affects the lifetime of a quantized, persistent
current state in a toroidal Bose-Einstein condensate (BEC). When the
temperature is increased, we find a decrease in the persistent current
lifetime. Comparing our measured decay rates to simple models of thermal
activation and quantum tunneling, we do not find agreement. We also measured
the size of hysteresis loops size in our superfluid ring as a function of
temperature, enabling us to extract the critical velocity. The measured
critical velocity is found to depend strongly on temperature, approaching the
zero temperature mean-field solution as the temperature is decreased. This
indicates that an appropriate definition of critical velocity must incorporate
the role of thermal fluctuations, something not explicitly contained in
traditional theories.


title: The power of online thinning in reducing discrepancy

abstract:
  Consider an infinite sequence of independent, uniformly chosen points from
$[0,1]^d$. After looking at each point in the sequence, an overseer is allowed
to either keep it or reject it, and this choice may depend on the locations of
all previously kept points. However, the overseer must keep at least one of
every two consecutive points. We call a sequence generated in this fashion a
\emph{two-thinning} sequence. Here, the purpose of the overseer is to control
the discrepancy of the empirical distribution of points, that is, after
selecting $n$ points, to reduce the maximal deviation of the number of points
inside any axis-parallel hyper-rectangle of volume $A$ from $nA$. Our main
result is an explicit low complexity two-thinning strategy which guarantees
discrepancy of $O(\log^{2d+1} n)$ for all $n$ with high probability (compare
with $\Theta(\sqrt{n\log\log n})$ without thinning). The case $d=1$ of this
result answers a question of Benjamini.
  We also extend the construction to achieve the same asymptotic bound for
($1+\beta$)-thinning, a set-up in which rejecting is only allowed with
probability $\beta$ independently for each point. In addition, we suggest an
improved and simplified strategy which we conjecture to guarantee discrepancy
of $O(\log^{d+1} n)$ (compare with $\theta(\log^d n)$, the best known
construction of a low discrepancy sequence). Finally, we provide theoretical
and empirical evidence for our conjecture, and provide simulations supporting
the viability of our construction for applications.


title:
A Formal, Resource Consumption-Preserving Translation of Actors to
  Haskell

abstract:
  We present a formal translation of an actor-based language with cooperative
scheduling to the functional language Haskell. The translation is proven
correct with respect to a formal semantics of the source language and a
high-level operational semantics of the target, i.e. a subset of Haskell. The
main correctness theorem is expressed in terms of a simulation relation between
the operational semantics of actor programs and their translation. This allows
us to then prove that the resource consumption is preserved over this
translation, as we establish an equivalence of the cost of the original and
Haskell-translated execution traces.


title:
The neutron within the deuteron as a surrogate for neutron-induced
  reactions

abstract:
  We propose the use of neutron poisons in reactions induced by radioactive
beams as a test of theoretical models aiming to relate neutron capture in
nuclei with neutron surrogate reactions such as (d,p) reactions. We exploit the
approximations necessary to obtain a direct relation between the two reactions;
surrogate vs. neutron capture. We also show how this is intimately related to
the momentum distribution of the neutron within the deuteron. The models we use
are based on the theory of inclusive breakup reactions commonly employed in the
treatment of incomplete fusion and surrogate method. Such theories were
developed in the 80's by Ichimura, Autern and Vincent [Phys. Rev. C 32, 431
(1985)], Udagawa and Tamura [Phys. Rev. C 24, 1348 (1981)] and Hussein and
McVoy [Nucl. Phys. A 445, 124 (1985)]. We use these theories to derive an
expression for the proton yield in the reaction A(d,p)B. The capture reaction
$n + A \rightarrow B$ is then extracted using reasonable approximations. By
recalling an old method proposed by Serber [Phys. Rev. 80, 1098 (1950); Nature
166, 709 (1950)] we explain how the momentum distribution of neutrons within
the deuteron will depend on the short-range dependence of the nucleon-nucleon
force. The relevance of our work to nucleosynthesis in the rapid neutron
capture process is emphasized.


title:
Divergence of Electric Field of Continuous and of a Point Charge for
  Relativistic and non-Relativistic Motion

abstract:
  In this paper we considered divergence of electric and of magnetic fields for
four cases: classical point charge, classical continuous charge, relativistic
point and relativistic continuous charges. Results for classical and
relativistic point charges are the same as in literature, i.e. Gauss's law is
valid. However results for time-varying classical and relativistic distributed
charges indicate that divergence of electric field is not zero even for volumes
of space where no charges are present. For these cases original Gauss's law
might require modification. Divergence of electric field seems to be far-field
type scalar anisotropic field, which is generated by time-varying electric
charges or currents. Results indicate that for these effects to be sufficiently
large to be experimentally observable the time variation of electric charges
and/or of currents should be very fast. Divergence of magnetic field is zero
for all cases.


title:
Improved next-to-leading order tidal heating and torquing of a Kerr
  black hole

abstract:
  We calculate the energy and angular momentum fluxes across the event horizon
of a tidally deformed, rapidly rotating black hole to next-to-leading order in
the curvature of the external spacetime. These are expressed in terms of tidal
quadrupole moments and their time derivatives, which provide a characterization
of a generic tidal environment. As an application of our results, we provide an
expression for the energy and angular-momentum fluxes across the horizon when
the black hole is a member of a binary system on a slowly-moving,
quasi-circular orbit. Our expressions are accurate to 1.5 post-Newtonian order
beyond the leading-order fluxes, but they are valid for arbitrary mass ratios.
We compare our results to those previously obtained in the case of an extreme
mass ratio binary, and find that they do not agree at the 1.5 post-Newtonian
order. We investigate a number of possible sources for this discrepancy, but
are ultimately unable to resolve it.


title: On deformed double current algebras for simple Lie algebras

abstract:
  We prove the equivalence of two presentations of deformed double current
algebras associated to a complex simple Lie algebra, the first one obtained via
a degeneration of affine Yangians while the other one naturally appeared in the
construction of the elliptic Casimir connection. We also construct a specific
central element of these algebras and, in type A, show that they contain a very
large center for certain values of their parameters.


title: Stable $\infty$-Operads and the multiplicative Yoneda lemma

abstract:
  We construct for every $\infty$-operad $\mathcal{O}^\otimes$ with certain
finite limits new $\infty$-operads of spectrum objects and of commutative group
objects in $\mathcal{O}$. We show that these are the universal stable resp.
additive $\infty$-operads obtained from $\mathcal{O}^\otimes$. We deduce that
for a stably (resp. additively) symmetric monoidal $\infty$-category
$\mathcal{C}$ the Yoneda embedding factors through the $\infty$-category of
exact, contravariant functors from $\mathcal{C}$ to the $\infty$-category of
spectra (resp. connective spectra) and admits a certain multiplicative
refinement. As an application we prove that the identity functor Sp $\to$ Sp is
initial among exact, lax symmetric monoidal endofunctors of the symmetric
monoidal $\infty$-category Sp of spectra with smash product.


title:
Linear Regression with an Unknown Permutation: Statistical and
  Computational Limits

abstract:
  Consider a noisy linear observation model with an unknown permutation, based
on observing $y = \Pi^* A x^* + w$, where $x^* \in \mathbb{R}^d$ is an unknown
vector, $\Pi^*$ is an unknown $n \times n$ permutation matrix, and $w \in
\mathbb{R}^n$ is additive Gaussian noise. We analyze the problem of permutation
recovery in a random design setting in which the entries of the matrix $A$ are
drawn i.i.d. from a standard Gaussian distribution, and establish sharp
conditions on the SNR, sample size $n$, and dimension $d$ under which $\Pi^*$
is exactly and approximately recoverable. On the computational front, we show
that the maximum likelihood estimate of $\Pi^*$ is NP-hard to compute, while
also providing a polynomial time algorithm when $d =1$.


title: On the Relation between K- and L-Theory of $C^*$-Algebras

abstract:
  We prove the existence of a map of spectra $\tau_A \colon kA \to lA$ between
connective topological K-theory and connective algebraic L-theory of a complex
$C^*$-algebra A which is natural in A and compatible with multiplicative
structures. We determine its effect on homotopy groups and as a consequence
obtain a natural equivalence $KA[1/2] \to LA[1/2]$ of periodic K- and L-theory
spectra after inverting 2. We show that this equivalence extends to K- and
L-theory of real $C^*$-algebras. Using this we give a comparison between the
real Baum-Connes conjecture and the L-theoretic Farrell-Jones conjecture. We
conclude that these conjectures are equivalent after inverting 2 if and only if
a certain completion conjecture in L-theory is true.


title:
TweeTime: A Minimally Supervised Method for Recognizing and Normalizing
  Time Expressions in Twitter

abstract:
  We describe TweeTIME, a temporal tagger for recognizing and normalizing time
expressions in Twitter. Most previous work in social media analysis has to rely
on temporal resolvers that are designed for well-edited text, and therefore
suffer from the reduced performance due to domain mismatch. We present a
minimally supervised method that learns from large quantities of unlabeled data
and requires no hand-engineered rules or hand-annotated training corpora.
TweeTIME achieves 0.68 F1 score on the end-to-end task of resolving date
expressions, outperforming a broad range of state-of-the-art systems.


title:
Notes on the Cluster Gutzwiller Method: Inhomogeneous Lattices,
  Excitations, and Cluster Time Evolution

abstract:
  Several perspectives of the cluster Gutzwiller method are briefly discussed.
I show that the cluster mean-field method can be used for large inhomogeneous
lattices, for computing local excitations, and for the time evolution of
correlated quantum systems.


title: Curving Flat Space-Time by Deformation Quantization?

abstract:
  We use a deformed differential structure to obtain a curved metric by a
deformation quantization of the flat space-time. In particular, by setting the
deformation parameters to be equal to physical constants we obtain the
Friedmann-Robertson-Walker (FRW) model for inflation and a deformed version of
the FRW space-time. By calculating classical Einstein-equations for the
extended space-time we obtain non-trivial solutions. Moreover, in this
framework we obtain the Moyal-Weyl, i.e. a constant non-commutative space-time,
by a consistency condition.


title:
NaSrMn2F7, NaCaFe2F7, and NaSrFe2F7: novel single crystal pyrochlore
  antiferromagnets

abstract:
  The crystal structures and magnetic properties of three previously unreported
A2B2F7 pyrochlore materials, NaSrMn2F7, NaCaFe2F7, and NaSrFe2F7 are presented.
In these compounds, either S=2 Fe2+ or S=5/2 Mn2+ is on the B site, while
nonmagnetic Na and Ca (Na and Sr) are disordered on the A site. The materials,
which were grown as crystals via the floating zone method, display high
effective magnetic moments and large Curie-Weiss thetas. Despite these
characteristics, freezing of the magnetic spins, characterized by peaks in the
susceptibility or specific heat, is not observed until low temperatures. The
empirical frustration index, f=- {\theta}cw/Tf, for the materials are 36
(NaSrMn2F7), 27 (NaSrFe2F7), and 19 (NaCaFe2F7). AC susceptibility, DC
susceptibility, and heat capacity measurements are used to characterize the
observed spin glass behavior. The results suggest that the compounds are
frustrated pyrochlore antiferromagnets with weak bond disorder. The magnetic
phenomena that these fluoride pyrochlores exhibit, in addition to their
availability as relatively large single crystals, make them promising
candidates for the study of geometric magnetic frustration.


title: Residual Networks of Residual Networks: Multilevel Residual Networks

abstract:
  A residual-networks family with hundreds or even thousands of layers
dominates major image recognition tasks, but building a network by simply
stacking residual blocks inevitably limits its optimization ability. This paper
proposes a novel residual-network architecture, Residual networks of Residual
networks (RoR), to dig the optimization ability of residual networks. RoR
substitutes optimizing residual mapping of residual mapping for optimizing
original residual mapping. In particular, RoR adds level-wise shortcut
connections upon original residual networks to promote the learning capability
of residual networks. More importantly, RoR can be applied to various kinds of
residual networks (ResNets, Pre-ResNets and WRN) and significantly boost their
performance. Our experiments demonstrate the effectiveness and versatility of
RoR, where it achieves the best performance in all residual-network-like
structures. Our RoR-3-WRN58-4+SD models achieve new state-of-the-art results on
CIFAR-10, CIFAR-100 and SVHN, with test errors 3.77%, 19.73% and 1.59%,
respectively. RoR-3 models also achieve state-of-the-art results compared to
ResNets on ImageNet data set.


title: Optical Magnetism in Planar Metamaterial Heterostructures

abstract:
  Harnessing artificial optical magnetism requires rather complex two- and
three-dimensional structures, examples include split-ring and fishnet
metamaterials and nanoparticles with non-trivial magnetic properties. By
contrast, dielectric properties can be tailored even in planar and
pattern-free, one-dimensional (1D) arrangements, for example metal/dielectric
multilayer metamaterials. These systems are extensively investigated due to
their hyperbolic and plasmonic response, which, however, is considered to be
limited to TM polarization, based on the general consensus that they do not
possess interesting magnetic properties. In this work, we tackle these two
seemingly unrelated issues simultaneously, by proposing conceptually and
demonstrating experimentally a mechanism for artificial magnetism in planar, 1D
metamaterials. We show experimentally that the magnetic response of
metal/high-index dielectric hyperbolic metamaterials can be anisotropic,
leading to frequency regimes of magnetic hyperbolic dispersion. We investigate
the implications of our results for TE polarization and show that such systems
can support TE interface-bound states, analogous to their TM counterparts,
surface plasmon polaritons. Our results simplify the structural complexity for
tailoring artificial magnetism in lithography-free systems and generalize the
concept of plasmonic and hyperbolic properties to encompass both TE and TM
polarizations at optical frequencies.


title:
Monotonicity of the period function of the Li\'enard equation of second
  kind

abstract:
  This paper is concerned with the monotonicity of the period function for
closed orbits of systems of the Li\'enard II type equation given by $\ddot{x} +
f(x)\dot{x}^{2} + g(x) = 0$. We generalize Chicone's result regarding the
monotonicity of the period function to planar Hamiltonian vector fields in the
presence of a position dependent mass. Sufficient conditions are also given for
the isochronicity of the potential in case of such a system.


title:
Correlated Interference from Uncorrelated Users in Bounded Ad Hoc
  Networks with Blockage

abstract:
  In this letter, we study the joint impact of user density, blockage density
and deployment area on the temporal correlation of interference for static and
highly mobile users. We show that even if the user locations become
uncorrelated, the interference level can still be correlated when the
deployment area is bounded and/or there is blockage. In addition, we study how
the correlation coefficients of interference scale at a high density of
blockage.


title:
Characterization of a scintillating lithium glass ultra-cold neutron
  detector

abstract:
  A $^{6}$Li glass based scintillation detector developed for the TRIUMF
neutron electric dipole moment experiment was characterized using the
ultra-cold neutron source at the Paul Scherrer Institute (PSI). The data
acquisition system for this detector was demonstrated to perform well at
rejecting backgrounds. An estimate of the absolute efficiency of background
rejection of $99.7\pm0.1$% is made. For variable ultra-cold neutron rate
(varying from $<$1 kHz to approx. 100 kHz per channel) and background rate seen
at the Paul Scherrer Institute, we estimate that the absolute detector
efficiency is $89.7^{+1.3}_{-1.9}$%. Finally a comparison with a commercial
Cascade detector was performed for a specific setup at the West-2 beamline of
the ultra-cold neutron source at PSI.


title:
Some observations about motivic tensor triangulated geometry over a
  finite field

abstract:
  We give a brief introduction to tensor triangulated geometry, a brief
introduction to various motivic categories, and then make some observations
about the conjectural structure of the tensor triangulated spectrum of the
Morel-Voevodsky stable homotopy category over a finite field.


title:
First-Principles Correlated Approach to the Normal State of Strontium
  Ruthenate

abstract:
  The interplay between multiple bands, sizable multi-band electronic
correlations and strong spin-orbit coupling may conspire in selecting a rather
unusual unconventional pairing symmetry in layered Sr$_{2}$RuO$_{4}$. This
mandates a detailed revisit of the normal state and, in particular, the
$T$-dependent incoherence-coherence crossover. Using a modern first-principles
correlated view, we study this issue in the actual structure of
Sr$_{2}$RuO$_{4}$ and present a unified and quantitative description of a range
of unusual physical responses in the normal state. Armed with these, we propose
that a new and important element, that of dominant multi-orbital charge
fluctuations in a Hund's metal, may be a primary pair glue for unconventional
superconductivity. Thereby we establish a connection between the normal state
responses and superconductivity in this system.


title:
Creation,transport and detection of imprinted magnetic solitons
  stabilized by spin-polarized current

abstract:
  With the recent proposition of skyrmion utilization in racetrack memories at
room temperature, skyrmionics has become a very attractive field. However, for
the stability of skyrmions, it is essential to incorporate the
Dzyaloshinskii-Moriya interaction (DMI) and the out-of-plane magnetic field
into the system. In this work, we explore a system without these interactions.
First, we propose a controlled way for the creation of magnetic skyrmions and
skyrmioniums imprinted on a ferromagnetic nanotrack via a nanopatterned
nanodisk with the magnetic vortex state. Then we investigate the detachment of
the imprinted spin textures from the underneath of the nanodisk, as well as its
transport by the spin-transfer torque imposed by spin-polarized current pulses
applied in the nanotrack. A prominent feature of the moving imprinted spin
texture is that its topological number Q is oscillating around the averaged
value of Q=0 as if it is a resonant state between the skyrmions with Q= +/- 1
and the bubble with Q=0. We may call it a resonant magnetic soliton (RMS). A
RMS moves along a straight line since it is free from the skyrmion Hall effect.
In our studied device, the same electrodes are employed to realize the
imprinted spin texture detachment and its transport. In addition, we have
investigated the interaction between the RMS and a magnetic tunnel junction
sensor, where the passing of the RMS in the nanotrack can be well detected. Our
results would be useful for the development of novel spintronic devices based
on moveable spin textures.


title: Critical Behaviour of Spanning Forests on Random Planar Graphs

abstract:
  As a follow-up of previous work of the authors, we analyse the statistical
mechanics model of random spanning forests on random planar graphs. Special
emphasis is given to the analysis of the critical behaviour. Exploiting an
exact relation with a model of O(-2)-loops and dimers, previously solved by
Kostov and Staudacher, we identify critical and multicritical loci, and find
them consistent with recent results of Bousquet-M\'elou and Courtiel. This is
also consistent with the KPZ relation, and the Berker-Kadanoff phase in the
anti-ferromagnetic regime of the Potts Model on periodic lattices, predicted by
Saleur. To our knowledge, this is the first known example of KPZ appearing
explicitly to work within a Berker-Kadanoff phase. We set up equations for the
generating function, at the value t=-1 of the fugacity, which is of
combinatorial interest, and we investigate the resulting numerical series, a
favourite problem of Tony Guttmann's.

categories: cond-mat.stat-mech hep-th math-ph math.CO math.MP


title: A Dynamic Service Description for Mobile Environments

abstract:
  With the increasing processing capability of mobile platforms and
advancements in Internet of Things, modern mobile devices have shown a
favorable prospect for on-the-go service provisioning. However, there is much
to be done to realize this. A detailed, dynamic, and lightweight service
description is an important requirement for automatic and efficient discovery,
selection, and subsequent provisioning of services over mobile devices.
Traditional approaches for service description are usually not directly
adaptable to mobile environments owing to the latter's dynamic and distinct
nature. In this paper, we propose a dynamic, lightweight, extensible, and
detailed service description especially designed for mobile environments,
considering crucial aspects such as isolated data source, collaborator
partners, and hardware aspects along with the functional, non-functional,
business, and contextual aspects. The description has been partitioned along
these lines and various parts of the description are distributed between
service registries and the mobile service providers. An up-to-date and light
weight description has been achieved by this, without compromising on the
overall consistency of the description. A prototype of the proposed system has
been implemented with the intent of validating the feasibility of the approach.
Further, the proposed approach is suitable for a heterogeneous environment
comprising both wired and wireless systems.


title: Hedetniemi's conjecture and adjoint functors in thin categories

abstract:
  We survey results on Hedetniemi's conjecture which are connected to adjoint
functors in the "thin" category of graphs, and expose the obstacles to
extending these results.


title: On the CR-curvature of Levi degenerate tube hypersurfaces

abstract:
  In our recent article (to appear in the Journal of Differential Geometry in
2016) we studied tube hypersurfaces in ${\mathbb C}^3$ that are 2-nondegenerate
and uniformly Levi degenerate of rank 1. In particular, we discovered that for
the CR-curvature of such a hypersurface to vanish it suffices to require that
only two coefficients (called $\Theta^2_{21}$ and $\Theta^2_{10}$) in the
expansion of a single component of the CR-curvature form be identically zero.
In this paper, we show that, surprisingly, the vanishing of the entire
CR-curvature is in fact implied by the vanishing of a single quantity derived
from $\Theta^2_{10}$. This fact strengthens the main theorem of the earlier
article and also leads to a remarkable system of partial differential
equations. Furthermore, we explicitly characterize the class of not necessarily
CR-flat tube hypersurfaces given by the vanishing of $\Theta^2_{21}$.


title:
Characterizing the feedback of magnetic field on the differential
  rotation of solar-like stars

abstract:
  The aim of this article is to study how the differential rotation of
solar-like stars is influenced by rotation rate and mass in presence of
magnetic fields generated by a convective dynamo. We use the ASH code to model
the convective dynamo of solar-like stars at various rotation rates and masses,
hence different effective Rossby numbers. We obtained models with either
prograde (solar-like) or retrograde (anti-solar-like) differential rotation.
The trends of differential rotation versus stellar rotation rate obtained for
simulations including the effect of the magnetic field are weaker compared with
hydro simulations ($\Delta \Omega \propto (\Omega/\Omega_{\odot})^{0.44}$ in
the MHD case and $\Delta \Omega \propto (\Omega/\Omega_{\odot})^{0.89}$ in the
hydro case), hence showing a better agreement with the observations. Analysis
of angular momentum transport revealed that the simulations with retrograde and
prograde differential rotation have opposite distribution of the viscous,
turbulent Reynolds stresses and meridional circulation contributions. The
thermal wind balance is achieved in the prograde cases. However, in retrograde
cases Reynolds stresses are dominant for high latitudes and near the top of the
convective layer. Baroclinic effects are stronger for faster rotating models.


title: Construction of bicuspidal rational complex projective plane curves

abstract:
  We give several constructions of bicuspidal rational complex projective plane
curves, and list the Newton pairs and the multiplicity sequences of the
singularities on the resulting curves.
  Although the existence of some of the listed cusp configurations is already
proved in the literature, the advantage of our approach is that on one hand we
explicitly state the Newton pairs and the multiplicity sequences of the
singularities on the curves, on the other hand, we also give birational
transformations transforming a conic or a bicuspidal curve with simple equation
to these rational bicuspidal curves with given cusp configurations.


title: On the Wegner orbital model

abstract:
  The Wegner orbital model is a class of random operators introduced by Wegner
to model the motion of a quantum particle with many internal degrees of freedom
(orbitals) in a disordered medium. We consider the case when the matrix
potential is Gaussian, and prove three results: localisation at strong
disorder, a Wegner-type estimate on the mean density of eigenvalues, and a
Minami-type estimate on the probability of having multiple eigenvalues in a
short interval. The last two results are proved in the more general setting of
deformed block-Gaussian matrices, which includes a class of Gaussian band
matrices as a special case. Emphasis is placed on the dependence of the bounds
on the number of orbitals. As an additional application, we improve the upper
bound on the localisation length for one-dimensional Gaussian band matrices.


title:
Compactness in MV-Topologies: Tychonoff Theorem and Stone-Cech
  Compactification

abstract:
  In this paper, we discuss some questions about compactness in MV-topological
spaces. More precisely, we first present a Tychonoff theorem for such a class
of fuzzy topological spaces and some consequence of this result, among which,
for example, the existence of products in the category of Stone MV-spaces and,
consequently, of coproducts in the one of limit cut complete MV-algebras. Then
we show that our Tychonoff theorem is equivalent, in ZF, to the Axiom of
Choice, classical Tychonoff theorem, and Lowen's analogous result for
lattice-valued fuzzy topology. Last, we show an extension of the Stone-Cech
compactification functor to the category of MV-topological spaces, and we
discuss its relationship with previous works on compactification for fuzzy
topological spaces.


title: Random sequential adsorption of polydisperse mixtures on lattices

abstract:
  Random sequential adsorption of linear and square particles with excluded
volume interaction is studied numerically on planar lattices considering
Gaussian distributions of lateral sizes of the incident particles, with several
values of the average and of the width-to-average ratio $w$. When the coverage
is plotted as function of the logarithm of time $t$, the maximum slope is
attained at a time $t_M$ of the same order of the time $\tau$ of incidence of
one monolayer, which is related to the molecular flux and/or sticking
coefficients. For various values of the average $\mu$ and $w$, we obtain
$1.5\tau < t_M < 5\tau$ for linear particles and $.3\tau< t_M < \tau$ for
square particles. At $t_M$, the coverages with linear and square particles are
near .3 and .2, respectively. Extrapolations show that coverages may vary with
$\mu$ up to 20% and 2% for linear and square particles, respectively, for
$\mu\ge 64$, fixed time, and constant $w$. All coverage $\theta$ versus $\log
t$ plots have approximately the same shape, but other quantities measured at
times of order $t_M$ help to distinguish narrow and broad incident
distributions. The adsorbed particle size distributions are close to the
incident ones up to long times for small $w$, but appreciably change in time
for larger $w$, acquiring a monotonically decreasing shape for $w = 1/2$ at
times of order $100\tau$ . At $t_M$, incident and adsorbed distributions are
approximately the same for $w \le 1/8$ and show significant differences for $w
\ge 1/2$; this result may be used as a consistency test in applications of the
model. The pair correlation function $g (r; t)$ for $w = 1/8$ has a well
defined oscillatory structure at $10t_M$, with a minimum at $r\approx\mu$ and
maximum at $r \approx 1.5\mu$, but this structure is not observed for $w \ge
1/4$.


title: Theory Perspective: SCES 2016

abstract:
  New discoveries and developments in almost every area of correlated electron
physics were presented at SCES 2016. Here, I provide a personal perspective on
some of these developments, highlighting some new ideas in computational
physics, discussing the "hidden order" challenges of cuprate and heavy electron
superconductors, the mysterious bulk excitations of the topological Kondo
insulator SmB$_{6}$ and new progress in research on quantum spin ice, iron
based superconductors and quantum criticality.


title: The Language of Generalization

abstract:
  Language provides simple ways of communicating generalizable knowledge to
each other (e.g., "Birds fly", "John hikes", "Fire makes smoke"). Though found
in every language and emerging early in development, the language of
generalization is philosophically puzzling and has resisted precise
formalization. Here, we propose the first formal account of generalizations
conveyed with language that makes quantitative predictions about human
understanding. We test our model in three diverse domains: generalizations
about categories (generic language), events (habitual language), and causes
(causal language). The model explains the gradience in human endorsement
through the interplay between a simple truth-conditional semantic theory and
diverse beliefs about properties, formalized in a probabilistic model of
language understanding. This work opens the door to understanding precisely how
abstract knowledge is learned from language.


title: Temporal Attention Model for Neural Machine Translation

abstract:
  Attention-based Neural Machine Translation (NMT) models suffer from attention
deficiency issues as has been observed in recent research. We propose a novel
mechanism to address some of these limitations and improve the NMT attention.
Specifically, our approach memorizes the alignments temporally (within each
sentence) and modulates the attention with the accumulated temporal memory, as
the decoder generates the candidate translation. We compare our approach
against the baseline NMT model and two other related approaches that address
this issue either explicitly or implicitly. Large-scale experiments on two
language pairs show that our approach achieves better and robust gains over the
baseline and related NMT approaches. Our model further outperforms strong SMT
baselines in some settings even without using ensembles.


title: Geometry and large N limits in Laughlin states

abstract:
  In these notes I survey geometric aspects of the lowest Landau level wave
functions, integer quantum Hall state and Laughlin states on compact Riemann
surfaces. In particular, I review geometric adiabatic transport on the moduli
spaces, derivation of the electromagnetic and gravitational anomalies,
Chern-Simons theory and adiabatic phase, and the relation to holomorphic line
bundles, Quillen metric, regularized spectral determinants, bosonisation
formulas on Riemann surfaces and asymptotic expansion of the Bergman kernel.


title: Magnetic Order and Mott Transition on the Checkerboard Lattice

abstract:
  The checkerboard lattice, with alternating 'crossed' plaquettes, serves as
the two dimensional analog of the pyrochlore lattice. The corner sharing
plaquette structure leads to a hugely degenerate ground state, and no magnetic
order, for classical spins with short range antiferromagnetic interaction. For
the half-filled Hubbard model on this structure, however, we find that the Mott
insulating phase involves virtual electronic processes that generate longer
range and multispin couplings. These couplings lift the degeneracy, selecting a
'flux like' state in the Mott insulator. Increasing temperature leads,
strangely, to a sharp crossover from this state to a '120 degree' correlated
state and then a paramagnet. Decrease in the Hubbard repulsion drives the
system towards an insulator-metal transition - the moments reduce, and a spin
disordered state wins over the flux state. Near the insulator-metal transition
the electron system displays a pseudogap extending over a large temperature
window.


title: Selection rules for ^48Cr

abstract:
  In the single j shell(f_{7/2}){}^{48} Cr is the first even-even nucleus for
which there are T=0 (Isoscalar) J=1^{+} states and T=1J=0^{+}These states are
here studied. This nucleus ,in the same model space, is mid-shell for both
neutrons and protons and this leads to many selection rules.


title:
Giant Electron-hole Charging Energy Asymmetry in Ultra-short Carbon
  Nanotubes

abstract:
  Making full usage of bipolar transport in single-wall carbon nanotube (SWCNT)
transistors could permit the development of two-in-one quantum devices with
ultra-short channels. We report on clean $\sim$10 to 100 nm long suspended
SWCNT transistors which display a large electron-hole transport asymmetry. The
devices consist of naked SWCNT channels contacted with sections of
SWCNT-under-annealed-gold. The annealed gold acts as an n-doping top gate which
creates nm-sharp barriers at the junctions between the contacts and naked
channel. These tunnel barriers define a single quantum dot (QD) whose charging
energies to add an electron or a hole are vastly different ($e-h$ charging
energy asymmetry). We parameterize the $e-h$ transport asymmetry by the ratio
of the hole and electron charging energies $\eta_{e-h}$. We show that this
asymmetry is maximized for short channels and small band gap SWCNTs. In a small
band gap SWCNT device, we demonstrate the fabrication of a two-in-one quantum
device acting as a QD for holes, and a much longer quantum bus for electrons.
In a 14 nm long channel, $\eta_{e-h}$ reaches up to 2.6 for a device with a
band gap of 270 meV. This strong $e-h$ transport asymmetry survives even at
room temperature.


title: Holographic relations in loop quantum gravity

abstract:
  It is shown that a relation between entropy and minimal area holds in loop
quantum gravity, reminiscent of the Ryu-Takayanagi relation.


title:
Subsonic Indicial Aerodynamics for Aerofoil's Unsteady Loads via
  Numerical and Analytical Methods

abstract:
  This study deals with generating aerodynamic indicial-admittance functions
for predicting the unsteady lift of two-dimensional aerofoils in subsonic flow,
using approximate numerical and analytical formulations. Both a step-change in
the angle of attack and a sharp-edge gust are suitably considered as small
perturbations. Novel contributions concern both a systematic analysis of the
computational simulations process and an effective theoretical synthesis of its
outcome, providing with sound cross-validation. Good practice for generating
the indicial-admittance functions via computational fluid dynamics is first
investigated for several Mach numbers, angles of attack and aerofoil profiles.
Convenient analytical approximations of such indicial functions are then
obtained by generalising those available for incompressible flow, taking
advantage of acoustic wave theory for the non-circulatory airload and
Prandtl-Glauert's scalability rule for the circulatory airload. An explicit
parametric formula is newly proposed for modelling the latter as function of
the Mach number in the absence of shock waves, while damped harmonic terms are
effectively introduced for better approximating the former. Appropriate tuning
of the analytical expressions is also derived in order to mimic the numerical
solutions and successfully verify the rigor of superposing circulatory and
non-circulatory theoretical contributions in the light of computational fluid
dynamics. Results are finally shown and critically addressed with respect to
the physical and mathematical assumptions employed, within a consistent
framework.


title: Overview of Advanced LIGO Adaptive Optics

abstract:
  This is an overview of the adaptive optics used in Advanced LIGO (aLIGO),
known as the thermal compensation system (TCS). The thermal compensation system
was designed to minimize thermally-induced spatial distortions in the
interferometer optical modes and to provide some correction for static
curvature errors in the core optics of aLIGO. The TCS is comprised of ring
heater actuators, spatially tunable CO$_{2}$ laser projectors and Hartmann
wavefront sensors. The system meets the requirements of correcting for nominal
distortion in Advanced LIGO to a maximum residual error of 5.4nm, weighted
across the laser beam, for up to 125W of laser input power into the
interferometer.


title: Fixed point free homeomorphisms of the complex plane

abstract:
  Our purpose in this article is to prove that the group $H({\bf C})$ of
homeomorphisms of the complex plane ${\bf C}$ is a metric group equipped with
the metric induced by uniform convergence of homeomorphisms and their inverses
on compacts and the set $$\left\{ h \in H({\bf C}) : ( \forall z \in {\bf C} )(
h(z) \neq z ) \right\} $$ of fixed point free homeomorphisms of the complex
plane is a conjugacy invariant dense $G_{\delta }$ subset of $H({\bf C})$.


title: Electron nuclear double resonance with donor-bound excitons in silicon

abstract:
  We present Auger-electron-detected magnetic resonance (AEDMR) experiments on
phosphorus donors in silicon, where the selective optical generation of
donor-bound excitons is used for the electrical detection of the electron spin
state. Because of the long dephasing times of the electron spins in
isotopically purified $^{28}$Si, weak microwave fields are sufficient, which
allow to realize broadband AEDMR in a commercial ESR resonator. Implementing
Auger-electron-detected ENDOR, we further demonstrate the optically-assisted
control of the nuclear spin under conditions where the hyperfine splitting is
not resolved in the optical spectrum. Compared to previous studies, this
significantly relaxes the requirements on the sample and the experimental
setup, e.g. with respect to strain, isotopic purity and temperature. We show
AEDMR of phosphorus donors in silicon with natural isotope composition, and
discuss the feasibility of ENDOR measurements also in this system.


title: Engineering matter interactions using squeezed vacuum

abstract:
  Virtually all interactions that are relevant for atomic and condensed matter
physics are mediated by quantum fluctuations of the electromagnetic field
vacuum. Consequently, controlling the vacuum fluctuations can be used to
engineer the strength and the range of interactions. Recent experiments have
used this premise to demonstrate novel quantum phases or entangling gates by
embedding electric dipoles in photonic cavities or waveguides, which modify the
electromagnetic fluctuations. Here, we show theoretically that the enhanced
fluctuations in the anti-squeezed quadrature of a squeezed vacuum state allows
for engineering interactions between electric dipoles without the need for a
photonic structure. Thus, the strength and range of the interactions can be
engineered in a time-dependent way by changing the spatial profile of the
squeezed vacuum in a travelling-wave geometry, which also allows the
implementation of chiral dissipative interactions. Using experimentally
realized squeezing parameters and including realistic losses, we predict single
atom cooperativities $C$ of up to 10 for the squeezed vacuum enhanced
interactions.


title:
Are Ultra-Long Gamma-Ray Bursts Caused by Blue Supergiant Collapsars,
  Newborn Magnetars, or White Dwarf Tidal Disruption Events?

abstract:
  Ultra-long gamma-ray bursts (ulGRBs) are a new population of GRBs with
extreme durations of $\sim 10^{4}$ s. Leading candidates for their origin are
blue supergiant collapsars, magnetars, and white dwarf tidal disruption events
(WD-TDEs) caused by massive black holes (BHs). Recent observations of
supernova-like (SN-like) bumps associated with ulGRBs challenged both the
WD-TDE and the blue supergiant models because of the detection of SNe and the
absence of hydrogen lines, respectively. We propose that WD-TDEs can
accommodate the observed SN-like bumps if the fallback WD matter releases
energy into the unbound WD ejecta. The observed ejecta energy, luminosity, and
velocity are explained by the gravitational energy, Eddington luminosity, and
escape velocity of the formed accretion disk, respectively. We also show that
the observed X-rays can ionize the ejecta, eliminating lines. The SN-like light
curves (SN 2011kl) for the ulGRB 111209A are consistent with all three models,
although a magnetar model is unnatural because the spin-down time required to
power the SN-like bump is a hundred times longer than the GRB. Our results
imply that TDEs are a possible energy source for SN-like events in general and
for ulGRBs in particular.


title:
Understanding the internal dynamics of elliptical galaxies without
  non-baryonic dark matter

abstract:
  Assuming virial equilibrium and Newtonian dynamics, low-mass early-type
galaxies have larger velocity dispersions than expected from the amount of
baryons they contain. The conventional interpretation of this finding is that
their dynamics is dominated by non-baryonic matter. However, there is also
strong evidence that many low-mass early-type galaxies formed as tidal dwarf
galaxies, which would contain almost no dark matter. Using an extensive
catalogue of early-type galaxies, we therefore discuss how the internal
dynamics of early-type galaxies in general can be understood by replacing the
assumption of non-baryonic dark matter with two alternative assumptions. The
first assumption is that Milgromian dynamics (i.e., MOND) is valid, which
changes the effective gravitational force in the weak-field limit. The second
assumption is that binary stars affect the observed line-of-sight velocity
dispersions. Some moderate discrepancies between observed and predicted
velocity dispersions remain also when these effects are implemented.
Nevertheless, the observed velocity dispersions in early-type galaxies can then
easily be explained without invoking the presence of non-baryonic dark matter
in them, but with already documented variations of the galaxy-wide stellar
initial mass function and non-equilibrium dynamics in some of the low-mass
early-type galaxies.


title:
Detection of sub-GeV Dark Matter and Solar Neutrinos via Chemical-Bond
  Breaking

abstract:
  We explore a new low-threshold direct-detection concept for dark matter,
based on the breaking of chemical bonds between atoms. This includes the
dissociation of molecules and the creation of defects in a lattice. With
thresholds of a few to 10's of eV, such an experiment could probe the nuclear
couplings of dark matter particles as light as a few MeV. We calculate the
expected rates for dark matter to break apart diatomic molecules, which we take
as a case study for more general systems. We briefly mention ideas for how
chemical-bond breaking might be detected in practice. We also discuss the
possibility of detecting solar neutrinos, including pp neutrinos, with this
experimental concept. With an event rate of $\mathcal{O}$(0.1/kg-year), large
exposures are required, but measuring low-energy solar neutrinos would provide
a crucial test of the solar model.


title:
ALMA observations of Lyman-alpha Blob 1: halo sub-structure illuminated
  from within

abstract:
  We present new Atacama Large Millimeter/Submillimeter Array (ALMA) 850um
continuum observations of the original Lyman-alpha Blob (LAB) in the SSA22
field at z=3.1 (SSA22-LAB01). The ALMA map resolves the previously identified
submillimeter source into three components with total flux density S_850 =
1.68+/-0.06 mJy, corresponding to a star formation rate of ~150 M_sun/yr. The
submillimeter sources are associated with several faint (m~27 mag) rest-frame
ultraviolet sources identified in Hubble Space Telescope Imaging Spectrograph
(STIS) clear filter imaging (~5850A). One of these companions is
spectroscopically confirmed with Keck MOSFIRE to lie within 20 projected kpc
and 250 km/s of one of the ALMA components. We postulate that some of these
STIS sources represent a population of low-mass star-forming satellites
surrounding the central submillimeter sources, potentially contributing to
their growth and activity through accretion. Using a high resolution
cosmological zoom simulation of a 10^13 M_sun halo at z=3, including stellar,
dust and Ly-alpha radiative transfer, we can model the ALMA+STIS observations
and demonstrate that Ly-alpha photons escaping from the central submillimeter
sources are expected to resonantly scatter in neutral hydrogen, the majority of
which is predicted to be associated with halo substructure. We show how this
process gives rise to extended Ly-alpha emission with similar surface
brightness and morphology to observed giant LABs.


title: Positivity of Curvature-Squared Corrections in Gravity

abstract:
  We study the Gauss-Bonnet (GB) term as the leading higher-curvature
correction to pure Einstein gravity. Assuming a tree-level ultraviolet
completion free of ghosts or tachyons, we prove that the GB term has a
nonnegative coefficient in dimensions greater than four. Our result follows
from unitarity of the spectral representation for a general ultraviolet
completion of the GB term.


title:
Estimating the fidelity of T gates using standard interleaved randomized
  benchmarking

abstract:
  Randomized benchmarking (RB) is an important protocol for robustly
characterizing the error rates of quantum gates. The technique is typically
applied to the Clifford gates since they form a group that satisfies a
convenient technical condition of forming a unitary 2-design, in addition to
having a tight connection to fault-tolerant quantum computing and an efficient
classical simulation. In order to achieve universal quantum computing one must
add at least one additional gate such as the T gate (also known as the $\pi$/8
gate). Here we propose and analyze a simple variation of the standard
interleaved RB protocol that can accurately estimate the average fidelity of
the T gate while retaining the many advantages of a unitary 2-design and the
fidelity guarantees that such a design delivers, as well as the efficient
classical simulation property of the Clifford group. Our work complements prior
methods that have succeeded in estimating T gate fidelities, but only by
relaxing the 2-design constraint and using a more complicated data analysis.


title:
On the origins of enigmatic stellar populations in Local Group galactic
  nuclei

abstract:
  We consider the origins of enigmatic stellar populations in four Local Group
galactic nuclei, specifically the Milky Way, M31, M32 and M33. These are
centrally concentrated blue stars, found in three out of the four nuclear star
clusters (NSCs) considered here. Their origins are unknown, but could include
blue straggler (BS) stars, extended horizontal branch stars and young recently
formed stars. Here, we calculate order-of-magnitude estimates for various
collision rates, as a function of the host NSC environment and distance from
the cluster centre. These rates are sufficiently high that BSs, formed via
collisions between main sequence (MS) stars, could contribute non-negligibly
($\sim$ 1-10% in mass) to every surface brightness profile, with the exception
of the Milky Way. Stellar evolution models show that the envelopes of red giant
branch (RGB) stars must be nearly completely stripped to significantly affect
their photometric appearance, which requires multiple collisions. Hence, the
collision rates for individual RGB stars are only sufficiently high in the
inner $\lesssim$ 0.1 pc of M31 and M32 for RGB destruction to occur. Collisions
between white dwarfs and MS stars, which should ablate the stars, could offer a
steady and significant supply of gas in every NSC in our sample. The gas could
either fragment to form new stars, or accrete onto old MS stars already
present. Thus, collisional processes could contribute significantly to the
observed blue excesses in M31 and M33; future studies should be aimed at better
constraining theoretical predictions to compliment existing and future
observational data.


title:
A planet in an 840-d orbit around a Kepler main-sequence A star found
  from phase modulation of its pulsations

abstract:
  We have detected a 12 M$_{\rm Jup}$ planet orbiting in or near the habitable
zone of a main-sequence A star via the pulsational phase shifts induced by
orbital motion. The planet has an orbital period of $840\pm20$ d and an
eccentricity of 0.15. All known planets orbiting main-sequence A stars have
been found via the transit method or by direct imaging. The absence of
astrometric or radial-velocity detections of planets around these hosts makes
ours the first discovery using the orbital motion. It is also the first A star
known to host a planet within 1$\sigma$ of the habitable zone. We find evidence
for planets in a large fraction of the parameter space where we are able to
detect them. This supports the idea that A stars harbor high-mass planets in
wide orbits.


title: Search for Lorentz Violation in km$^3$-Scale Neutrino Telescopes

abstract:
  Kilometer$^3$-scale neutrino detectors such as IceCube, ANTARES, and the
proposed Km3Net neutrino observatory in the Mediterranean have measured, and
will continue to characterize, the atmospheric neutrino spectrum above 1 TeV.
Such precise measurements enable us to probe new neutrino physics, in
particular, those that arise from Lorentz violation. In this paper, we first
relate the effective new physics hamiltonian terms with the Lorentz violating
literature. Second, we calculate the oscillation probability formulas for the
two-level $\nu_\mu-\nu_\tau$ sector. Finally, we comment on some of the
challenges and outlook for this analysis.


title:
Millihertz Quasi-periodic Oscillations in 4U 1636-536: Putting Possible
  Constraints on the Neutron Star Size

abstract:
  Based on previous studies of quasi-periodic oscillations in neutron star
LMXBs, mHz quasi-periodic oscillations (QPO) are believed to be related to
`marginally stable' burning on the neutron star (NS) surface. Our study of
phase resolved energy spectra of these oscillations in 4U 1636-53 shows that
the oscillations are not caused by variations in the blackbody temperature of
the neutron star, but reveals a correlation between the change of the count
rate during the mHz QPO pulse and the spatial extend of a region emitting
blackbody emission. The maximum size of the emission area
$R^2_{\mathrm{BB}}=216.7^{+93.2}_{-86.4}$km$^2$, provides the direct evidence
that the oscillations originate from a variable surface area constrained on the
NS and are therefore not related to instabilities in the accretion disk. The
obtained lower limit on the size of the neutron star (11.0 km) rules out
equations of state that prefer small NS radii. Observations of mHz QPOs in NS
LMXBs with NICER and eXTP will reduce the statistical uncertainty in the lower
limit on the NS radius, which together with better estimates of the hardening
factor and distance, will allow improving discrimination between different
equations of state and compact star models. Furthermore, future missions will
allow us to measure the peak blackbody emission area for a single mHz QPO
pulse, which will push the lower limit to larger radii.


title:
Phenomenological approach to hyperkagome spin liquid: gauge fields and
  spinons without slave particles

abstract:
  A number of experiments on the hyperkagome iridate, Na$_4$Ir$_3$O$_8$,
suggest existence of a gapless quantum spin liquid state at low temperature.
Circumventing the slave particle approach commonly used in theoretical analyses
of frustrated magnets, we provide a more intuitive, albeit more
phenomenological, construction of a quantum spin liquid state for the
hyperkagome Heisenberg model. An effective monomer-dimer model on the
hyperkagome lattice is proposed a la Hao and Tchernyshyov's approach cultivated
from the Husimi cactus model. Employing an arrow representation for the
monomer-dimer model, we obtain a compact $U(1)$ gauge theory with a finite
density of Fermionic spinons on the hyperoctagon lattice. The resulting theory
and its mean field treatments lead to remarkable agreement with previous
slave-particle construction of a quantum spin liquid state on the hyperkagome
lattice. Our results offer novel insights on theoretical understanding of the
emergence of spinon Fermi surfaces and useful predictions for future
experiments.


title: Distributions for neutral Higgs production in the NMSSM

abstract:
  A novel computation of the fully-differential cross section for neutral
Higgs-boson production through gluon fusion in the CP-conserving NMSSM is
presented. Based on the calculation of NLO corrections to the total cross
section [1], we implemented the NMSSM amplitudes in three codes, applying
different resummation techniques: analytic transverse-momentum resummation at
NLO+NLL, and two fully-differential NLO+PS Monte-Carlo approaches using the
MC@NLO and POWHEG matching procedures, respectively. We study phenomenological
predictions for distributions in the NMSSM with a special emphasis on the Higgs
transverse-momentum spectrum. Reasonable agreement among the various approaches
is found, once well-motivated choices for the unphysical matching scales and
the determination of the related uncertainties are made.


title:
High-temperature large-gap quantum anomalous Hall insulator in ultrathin
  double perovskite films

abstract:
  Motivated by the goal of realizing topological phases in thin films and
heterostructures of correlated oxides, we propose here a quantum anomalous Hall
insulator (QAHI) in ultrathin films of double perovskites based on mixed 3d-5d
or 3d-4d transition metal ions, grown along the [111] direction. Considering
the specific case of ultrathin Ba2FeReO6, we present a theoretical analysis of
an effective Hamiltonian derived from first-principles. We establish that a
strong spin-orbit coupling at Re site, t2g symmetry of the low-energy d-bands,
polarity of its [111] orientation of perovskite structure, and mixed 3d-5d
chemistry results in room temperature magnetism with a robust QAHI state of
Chern number C=1 and a large band-gap. We uncover and highlight a
non-relativistic orbital-Rashba-type effect in addition to the spin-orbit
coupling, that governs this QAHI state. Our prediction of a large topological
band-gap of ~100 meV in electronic structure, and a magnetic transition
temperature Tc~300K estimated by Monte Carlo simulations, is expected to
stimulate experimental efforts at synthesis of such films and enable possible
practical applications of its dissipationless edge currents.


title:
Measuring Magnetic Fields from Water Masers in the Synchrotron
  Protostellar Jet in W3(H$_2$O)

abstract:
  We report full polarimetric VLBA observations of water masers towards the
Turner-Welch Object in the W3(OH) high-mass star forming complex. This object
drives a synchrotron jet, which is quite exceptional for a high-mass protostar,
and is associated with a strongly polarized water maser source, W3(H$_2$O),
making it an optimal target to investigate the role of magnetic fields on the
innermost scales of protostellar disk-jet systems. The linearly polarized
emission from water masers provides clues on the orientation of the local
magnetic field, while the measurement of the Zeeman splitting from circular
polarization provides its strength. The water masers trace a bipolar, biconical
outflow at the center of the synchrotron jet. Although on scales of a few
thousand AU the magnetic field inferred from the masers is on average
orientated along the flow axis, on smaller scales (10s to 100s of AU), we have
revealed a misalignment between the magnetic field and the velocity vectors,
which arises from the compression of the field component along the shock front.
Our measurements support a scenario where the magnetic field would evolve from
having a dominant component parallel to the outflow velocity in the pre-shock
gas, with field strengths of the order of a few tens of mG (at densities of
$10^7$ cm$^{-3}$), to being mainly dominated by the perpendicular component of
order of a few hundred of mG in the post-shock gas where the water masers are
excited (at densities of $10^9$ cm$^{-3}$). The general implication is that in
the undisturbed (i.e. not-shocked) circumstellar gas, the flow velocities would
follow closely the magnetic field lines, while in the gas shocked by the
prostostellar jet the magnetic field would be re-configured to be parallel to
the shock front.


title: Localization techniques in quantum field theories

abstract:
  This is the foreword to the special volume on localization techniques in
quantum field theory. We summarize the individual chapters and their relation.


title: Introduction to localization in quantum field theory

abstract:
  This is the introductory chapter to the volume. We review the main idea of
the localization technique and its brief history both in geometry and in QFT.
We discuss localization in diverse dimensions and give an overview of the major
applications of the localization calculations for supersymmetric theories. We
explain the focus of the present volume.


title: Review of localization in geometry

abstract:
  Review of localization in geometry: equivariant cohomology, characteristic
classes, Atiyah-Bott formula, Atiyah-Singer equivariant index formula,
Mathai-Quillen formalism


title: Supersymmetric localization in two dimensions

abstract:
  This is an introductory review to localization techniques in supersymmetric
two-dimensional gauge theories. In particular we describe how to construct
Lagrangians of N=(2,2) theories on curved spaces, and how to compute their
partition functions and certain correlators on the sphere, the hemisphere and
other curved backgrounds. We also describe how to evaluate the partition
function of N=(0,2) theories on the torus, known as the elliptic genus. Finally
we summarize some of the applications, in particular to probe mirror symmetry
and other non-perturbative dualities.


title: Gromov-Witten invariants and localization

abstract:
  We give a pedagogical review of the computation of Gromov-Witten invariants
via localization in 2D gauged linear sigma models. We explain the relationship
between the two-sphere partition function of the theory and the Kahler
potential on the conformal manifold. We show how the Kahler potential can be
assembled from classical, perturbative, and non-perturbative contributions, and
explain how the non-perturbative contributions are related to the Gromov-Witten
invariants of the corresponding Calabi-Yau manifold. We then explain how
localization enables efficient calculation of the two-sphere partition function
and, ultimately, the Gromov-Witten invariants themselves.


title: An introduction to supersymmetric field theories in curved space

abstract:
  In this review, we give a pedagogical introduction to a systematic framework
for constructing and analyzing supersymmetric field theories on curved
spacetime manifolds. The framework is based on the use of off-shell
supergravity background fields. We present the general principles, which
broadly apply to theories with different amounts of supersymmetry in diverse
dimensions, as well as specific applications to N=1 theories in four dimensions
and their three-dimensional cousins with N=2 supersymmetry.


title: Localization on three-dimensional manifolds

abstract:
  In this review article we describe the localization of three dimensional N=2
supersymmetric theories on compact manifolds, including the squashed sphere,
S^3_b, the lens space, S^3_b/Z_p, and S^2 x S^1. We describe how to write
supersymmetric actions on these spaces, and then compute the partition
functions and other supersymmetric observables by employing the localization
argument. We briefly survey some applications of these computations.


title: Localization at large N in Chern-Simons-matter theories

abstract:
  We review some exact results for the matrix models appearing in the
localization of Chern-Simons-matter theories, focusing on the structure of
non-perturbative effects and onthe M-theory expansion of ABJM theory. We also
summarize some of the results obtained for other Chern-Simons-matter theories,
as well as recent applications to topological strings.


title: The F-Theorem and F-Maximization

abstract:
  This contribution contains a review of the role of the three-sphere free
energy F in recent developments related to the F-theorem and F-maximization.
The F-theorem states that for any Lorentz-invariant RG trajectory connecting a
conformal field theory CFT_UV in the ultraviolet to a conformal field theory
CFT_IR, the F-coefficient decreases: F_UV > F_IR. I provide many examples of
CFTs where one can compute F, approximately or exactly, and discuss various
checks of the F-theorem. F-maximization is the principle that in an N=2 SCFT,
viewed as the deep IR limit of an RG trajectory preserving N=2 supersymmetry,
the superconformal R-symmetry maximizes F within the set of all R-symmetries
preserved by the RG trajectory. I review the derivation of this result and
provide examples.


title: Perturbative and nonperturbative aspects of complex Chern-Simons Theory

abstract:
  We present an elementary review of some aspects of Chern-Simons theory with
complex gauge group SL(N,C). We discuss some of the challenges in defining the
theory as a full-fledged TQFT, as well as some successes inspired by the 3d-3d
correspondence. The 3d-3d correspondence relates partition functions (and other
aspects) of complex Chern-Simons theory on a 3-manifold M to supersymmetric
partition functions (and other observables) in an associated 3d theory T[M].
Many of these observables may be computed by supersymmetric localization. We
present several prominent applications to 3-manifold topology and number theory
in light of the 3d-3d correspondence.


title: N=2 SUSY gauge theories on S^4

abstract:
  We review exact results in N=2 supersymmetric gauge theories defined on S^4
and its deformation. We first summarize the construction of rigid SUSY theories
on curved backgrounds based on off-shell supergravity, then explain how to
apply localization principle to supersymmetric path integrals. Closed formulae
for partition function as well as expectation values of non-local BPS
observables are presented.


title: Localization and AdS/CFT Correspondence

abstract:
  An interplay between localization and holography is reviewed with the
emphasis on the AdS_5/CFT_4 correspondence.


title: A brief review of the 2d/4d correspondences

abstract:
  An elementary introduction to the 2d/4d correspondences is given. After
quickly reviewing the 2d q-deformed Yang-Mills theory and the Liouville theory,
we will introduce 4d theories obtained by coupling trifundamentals to SU(2)
gauge fields. We will then see concretely that the supersymmetric partition
function of these theories on S^3 x S^1 and on S^4 is given respectively by the
q-deformed Yang-Mills theory and the Liouville theory. After giving a short
discussion on how this correspondence may be understood from the viewpoint of
the 6d N=(2,0) theory, we conclude the review by enumerating future directions.
Most of the technical points will be referred to more detailed review articles.


title: The supersymmetric index in four dimensions

abstract:
  We review the calculation and properties of the supersymmetric index for four
dimensional N=1 theories, illustrating its physical significance in several
examples.


title: Review of localization for 5d supersymmetric gauge theories

abstract:
  We give a pedagogical review of the localization of supersymmetric gauge
theory on 5d toric Sasaki-Einstein manifolds. We construct the cohomological
complex resulting from supersymmetry and consider its natural toric
deformations with all equivariant parameters turned on. We also give detailed
discussion on how the Sasaki-Einstein geometry permeates every aspect of the
calculation, from Killing spinor, vanishing theorems to the index theorems.


title: Matrix models for 5d super Yang-Mills

abstract:
  In this contribution to the review on localization in gauge theories we
investigate the matrix models derived from localizing N=1 super Yang-Mills on
S^5. We consider the large-N limit and attempt to solve the matrix model by a
saddle-point approximation. In general it is not possible to find an analytic
solution, but at the weak and the strong limits of the 't Hooft coupling there
are dramatic simplifications that allows us to extract most of the interesting
information. At weak coupling we show that the matrix model is close to the
Gaussian matrix model and that the free-energy scales as N^2. At strong
coupling we show that if the theory contains one adjoint hypermultiplet then
the free-energy scales as N^3. We also find the expectation value of a
supersymmetric Wilson loop that wraps the equator. We demonstrate how to
extract the effective couplings and reproduce results of Seiberg. Finally, we
compare to results for the six-dimensional (2,0) theory derived using the
AdS/CFT correspondence. We show that by choosing the hypermultiplet mass such
that the supersymmetry is enhanced to N=2, the Wilson loop result matches the
analogous calculation using AdS/CFT. The free-energies differ by a rational
fraction.


title: Holomorphic blocks and the 5d AGT correspondence

abstract:
  We review the holomorphic block factorisation of partition functions of
supersymmetric theories on compact manifolds in various dimensions. We then
show how to interpret 3d and 5d partition functions as correlation functions
with underlying symmetry given by a deformation of the Virasoro algebra.


title: Indices for 6 dimensional superconformal field theories

abstract:
  We review some recent developments in the 6 dimensional (2, 0) superconformal
field theories, focusing on their BPS spectra in the Coulomb and symmetric
phases computed by various Witten indices. We shall discuss the instanton
partition function of 5d maximal super-Yang-Mills theory, and the 6d
superconformal index.


title: Anisotropic plasmas from axion and dilaton deformations

abstract:
  We construct black hole solutions of type IIB supergravity that are
holographically dual to anisotropic plasmas arising from deformations of an
infinite class of four-dimensional CFTs. The CFTs are dual to $AdS_5\times
X_5$, where $X_5$ is an Einstein manifold, and the deformations involve the
type IIB axion and dilaton, with non-trivial periodic dependence on one of the
spatial directions of the CFT. At low temperatures the solutions approach
smooth domain wall solutions with the same $AdS_5\times X_5$ solution appearing
in the far IR. For sufficiently large deformations an intermediate scaling
regime appears which is governed by a Lifshitz-like scaling solution. We
calculate the DC thermal conductivity and some components of the shear
viscosity tensor.


title: Neuroevolution-Based Inverse Reinforcement Learning

abstract:
  The problem of Learning from Demonstration is targeted at learning to perform
tasks based on observed examples. One approach to Learning from Demonstration
is Inverse Reinforcement Learning, in which actions are observed to infer
rewards. This work combines a feature based state evaluation approach to
Inverse Reinforcement Learning with neuroevolution, a paradigm for modifying
neural networks based on their performance on a given task. Neural networks are
used to learn from a demonstrated expert policy and are evolved to generate a
policy similar to the demonstration. The algorithm is discussed and evaluated
against competitive feature-based Inverse Reinforcement Learning approaches. At
the cost of execution time, neural networks allow for non-linear combinations
of features in state evaluations. These valuations may correspond to state
value or state reward. This results in better correspondence to observed
examples as opposed to using linear combinations. This work also extends
existing work on Bayesian Non-Parametric Feature Construction for Inverse
Reinforcement Learning by using non-linear combinations of intermediate data to
improve performance. The algorithm is observed to be specifically suitable for
a linearly solvable non-deterministic Markov Decision Processes in which
multiple rewards are sparsely scattered in state space. A conclusive
performance hierarchy between evaluated algorithms is presented.


title:
Electrostatically confined monolayer graphene quantum dots with orbital
  and valley splittings

abstract:
  The electrostatic confinement of massless charge carriers is hampered by
Klein tunneling. Circumventing this problem in graphene mainly relies on
carving out nanostructures or applying electric displacement fields to open a
band gap in bilayer graphene. So far, these approaches suffer from edge
disorder or insufficiently controlled localization of electrons. Here we
realize an alternative strategy in monolayer graphene, by combining a
homogeneous magnetic field and electrostatic confinement. Using the tip of a
scanning tunneling microscope, we induce a confining potential in the Landau
gaps of bulk graphene without the need for physical edges. Gating the localized
states towards the Fermi energy leads to regular charging sequences with more
than 40 Coulomb peaks exhibiting typical addition energies of 7-20 meV. Orbital
splittings of 4-10 meV and a valley splitting of about 3 meV for the first
orbital state can be deduced. These experimental observations are
quantitatively reproduced by tight binding calculations, which include the
interactions of the graphene with the aligned hexagonal boron nitride
substrate. The demonstrated confinement approach appears suitable to create
quantum dots with well-defined wave function properties beyond the reach of
traditional techniques.


title:
Chemically active colloids near osmotic-responsive walls with
  surface-chemistry gradients

abstract:
  Chemically active colloids move by creating gradients in the composition of
the surrounding solution and by exploiting the differences in their
interactions with the various molecular species in solution. If such particles
move near boundaries, e.g., the walls of the container confining the
suspension, gradients in the composition of the solution are also created along
the wall. This give rise to chemi-osmosis (via the interactions of the wall
with the molecular species forming the solution), which drives flows coupling
back to the colloid and thus influences its motility. Employing an approximate
"point-particle" analysis, we show analytically that -- owing to this kind of
induced active response (chemi-osmosis) of the wall -- such chemically active
colloids can align with, and follow, gradients in the surface chemistry of the
wall. In this sense, these artificial "swimmers" exhibit a primitive form of
thigmotaxis with the meaning of sensing the proximity of a (not necessarily
discontinuous) physical change in the environment. We show that the alignment
with the surface-chemistry gradient is generic for chemically active colloids
as long as they exhibit motility in an unbounded fluid, i.e., this phenomenon
does not depend on the exact details of the propulsion mechanism. The results
are discussed in the context of simple models of chemical activity,
corresponding to Janus particles with "source" chemical reactions on one half
of the surface and either "inert" or "sink" reactions over the other half.


title: Tricriticality in Crossed Ising Chains

abstract:
  We explore the phase diagram of Ising spins on one-dimensional chains which
criss-cross in two perpendicular directions and which are connected by
interchain couplings. This system is of interest as a simpler, classical analog
of a quantum Hamiltonian which has been proposed as a model of magnetic
behavior in Nb$_{12}$O$_{29}$ and also, conceptually, as a geometry which is
intermediate between one and two dimensions. Using mean field theory as well as
Metropolis Monte Carlo and Wang-Landau simulations, we locate quantitatively
the boundaries of four ordered phases. Each becomes an effective Ising model
with unique effective couplings at large interchain coupling. Away from this
limit we demonstrate non-trivial critical behavior, including tricritical
points which separate first and second order phase transitions. Finally, we
present evidence that this model belongs to the 2D Ising universality class.


title: Graphite Revisited

abstract:
  Laboratory measurements are used to constrain the dielectric tensor for
graphite, from microwave to X-ray frequencies. The dielectric tensor is
strongly anisotropic even at X-ray energies. The discrete dipole approximation
is employed for accurate calculations of absorption and scattering by
single-crystal graphite spheres and spheroids. For randomly-oriented
single-crystal grains, the so-called 1/3 - 2/3 approximation for calculating
absorption and scattering cross sections is exact in the limit a/lambda -> 0,
provides better than ~10% accuracy in the optical and UV even when a/lambda is
not small, but becomes increasingly inaccurate at infrared wavelengths, with
errors as large as ~40% at lambda = 10 micron. For turbostratic graphite
grains, the Bruggeman and Maxwell Garnett treatments yield similar cross
sections in the optical and ultraviolet, but diverge in the infrared, with
predicted cross sections differing by over an order of magnitude in the
far-infrared. It is argued that the Maxwell Garnett estimate is likely to be
more realistic, and is recommended. The out-of-plane lattice resonance of
graphite near 11.5 micron may be observable in absorption with the MIRI
spectrograph on JWST. Aligned graphite grains, if present in the ISM, could
produce polarized X-ray absorption and polarized X-ray scattering near the
carbon K edge.


title:
A comparison of the innate flexibilities of six chains in F$_1$-ATPase
  with identical secondary and tertiary folds; 3 active enzymes and 3
  structural proteins

abstract:
  The $\alpha$ and $\beta$ subunits comprising the hexameric assembly of
F1-ATPase share a high degree of structural identity, though low primary
identity. Each subunit binds nucleotide in similar pockets, yet only $\beta$
subunits are catalytically active. Why? We re-examine their internal symmetry
axes and observe interesting differences. Dividing each chain into an
N-terminal head region, a C-terminal foot region, and a central torso, we
observe (1) that while the foot and head regions in all chains obtain high and
similar mobility, the torsos obtain different mobility profiles, with the
$\beta$ subunits exhibiting a higher motility compared to the $\alpha$
subunits, a trend supported by the crystallographic B-factors. The $\beta$
subunits have greater torso mobility by having fewer distributed, nonlocal
packing interactions providing a spacious and soft connectivity, and offsetting
the resultant softness with local stiffness elements, including an additional
$\beta$ sheet. (2) A loop near the nucleotide binding-domain of the $\beta$
subunits, absent in the $\alpha$ subunits, swings to create a large variation
in the occlusion of the nucleotide binding region. (3) A combination of the
softest three eigenmodes significantly reduces the RMSD between the open and
closed conformations of the $\beta$ subnits. (4) Comparisons of computed and
observed crystallographic B-factors suggest a suppression of a particular
symmetry axis in an $\alpha$ subunit. (5) Unexpectedly, the soft intra-monomer
oscillations pertain to distortions that do not create inter-monomer steric
clashes in the assembly, suggesting that structural optimization of the
assembly evolved at all levels of complexity.


title:
Similarity in Observable Behaviors: A Synthesis of Studies with
  Implications for Socially-Aware Educational Technology Design

abstract:
  Conversation is like an intricate partner dance and behavioral convergence,
or the similarity in observable behaviors of partners over time, can lead to
shared understanding, changed beliefs and increased rapport. This article
describes a synthesis of three strands of our work on fine-grained analysis of
conversational interaction in peer tutoring at the paralinguistic and verbal
levels, in an attempt to better understand the phenomenon of behavioral
convergence and its relationship to social and cognitive constructs.
Implications for development of socially-aware agents that can improve task
performance through convergence to and from the human learner's behavior are
discussed.


title: Open Gromov-Witten Invariants from the Augmentation Polynomial

abstract:
  A conjecture of Aganagic and Vafa relates the open Gromov-Witten theory of
$X=\mathcal{O}_{\mathbb{P}^{1}}(-1,-1)$ to the augmentation polynomial of
Legendrian contact homology. We describe how to use this conjecture to compute
genus zero, one boundary component open Gromov-Witten invariants for Lagrangian
submanifolds $L_{K}\subset X$ obtained from the conormal bundles of knots
$K\subset S^{3}$. This computation is then performed for two non-toric examples
(the figure-eight and three-twist knots). For $(r,s)$ torus knots, the open
Gromov-Witten invariants can also be computed using Atiyah-Bott localization.
Using this result for the unknot and the $(3,2)$ torus knot, we show that the
augmentation polynomial can be derived from these open Gromov-Witten
invariants.


title:
Photon paths in the hyperbolic topological black hole spacetime of
  conformal Weyl gravity

abstract:
  In this work we find analytical solutions to the null geodesics in the
hyperbolic topological black hole spacetime of conformal Weyl gravity in an
invariant $2$-plane given by the orbits of an azimuthal Killing vector. Exact
expressions for the (non-compact) horizons are found, which depend on the
cosmological constant and the coupling constants of conformal Weyl gravity. The
angular motion is examined qualitatively by means of an effective potential;
quantitatively, the equation of motion is solved in terms of the
$\wp$-Weierstra{\ss} elliptic function. Thus, we find the deflection angle for
photons without using any approximation, which is a novel result for this
topology.


title: AG Pegasi - now a classical symbiotic star in outburst?

abstract:
  Optical spectroscopy study of the recent AG Peg outburst observed during the
second half of 2015 is presented. Considerable variations of the intensity and
the shape of the spectral features as well as the changes of the hot component
parameters, caused by the outburst, are discussed and certain similarities
between the outburst of AG Peg and the outburst of a classical symbiotic stars
are shown. It seems that after the end of the symbiotic nova phase, AG Peg
became a member of the classical symbiotic stars group.


title:
Formation of ordered and disordered interfacial films in immiscible
  metal alloys

abstract:
  Atomistic simulations are used to study segregation-induced intergranular
film formation in Cu-Zr and Cu-Nb alloys. While Cu-Zr forms structurally
disordered or amorphous films, ordered films comprised of a second phase
usually precipitate in Cu-Nb, with a critical nucleation size of ~1 nm below
which the ordered phase cannot form. While the ordered film is retained at high
temperature for a low energy {\Sigma}11 (113) boundary, a disordering
transition is observed for a high energy {\Sigma}5 (310) boundary at low dopant
concentrations. Finally, the effect of free surfaces on dopant segregation and
intergranular film formation is investigated for both alloys.


title:
Hydrodynamic Predictions for Mixed Harmonic Correlations in 200 GeV
  Au+Au Collisions

abstract:
  Recent measurements at the LHC involve the correlation of different azimuthal
flow harmonics $v_n$. These new observables add constraints to theoretical
models and probe aspects of the system that are independent of the traditional
single-harmonic measurements such as 2- and multi-particle cumulants
$v_n\{m\}$. Many of these new observables have not yet been measured at RHIC,
leaving an opportunity to make predictions as a test of models across energies.
We make predictions using NeXSPheRIO, a hydrodynamical model which has
accurately reproduced a large set of single-harmonic correlations in a large
range of transverse momenta and centralities at RHIC. Our predictions thus
provide an important baseline for comparison to correlations of flow harmonics,
which contain non-trivial information about the initial state as well as QGP
transport properties. We also point out significant biases that can appear when
using wide centrality bins and non-trivial event weighting, necessitating care
in performing experimental analyses and in comparing theoretical calculations
to these measurements.


title:
Individual band with higher Chern numbers in double perovskite {001}
  monolayers

abstract:
  We show a tight-binding model for double perovskite monolayers grown in the
{001} crystallographic direction can exhibit higher Chern numbers for the
lowest band of the model dispersion in the absence of an applied magnetic
field, including $\pm2$, $\pm4$, $\pm6$, and $\pm8$, for model parameters and
terms relevant to Sr$_2$CrWO$_6$ (SCWO). We further show it is possible to tune
between these different topological phases by applying a weak in-plane magnetic
field. These results may be important for experimentally realizing exotic band
topologies -- and even quantum anomalous Hall insulators with higher Chern
numbers -- based on this physics.


title: Cellular Legendrian contact homology for surfaces, part I

abstract:
  We give a computation of the Legendrian contact homology (LCH) DGA for an
arbitrary generic Legendrian surface $L$ in the $1$-jet space of a surface. As
input we require a suitable cellular decomposition of the base projection of
$L$. A collection of generators is associated to each cell, and the
differential is given by explicit matrix formulas. In the present article, we
prove that the equivalence class of this cellular DGA does not depend on the
choice of decomposition, and in the sequel [35] we use this result to show that
the cellular DGA is equivalent to the usual Legendrian contact homology DGA
defined via holomorphic curves.
  Extensions are made to allow Legendrians with non-generic cone-point
singularities. We apply our approach to compute the LCH DGA for several
examples including an infinite family, and to give general formulas for DGAs of
front spinnings allowing for the axis of symmetry to intersect $L$.


title:
Robo-AO Kitt Peak: Status of the system and deployment of a sub-electron
  readnoise IR camera to detect low-mass companions

abstract:
  We have started an initial three-year deployment of Robo-AO at the 2.1-m
telescope at Kitt Peak, Arizona as of November 2015. We report here on the
project status and two new developments with the Robo-AO KP system: the
commissioning of a sub-electron readnoise SAPHIRA near-infrared camera, which
will allow us to widen the scope of possible targets to low-mass stellar and
substellar objects; and, performance analysis and tuning of the adaptive optics
system, which will improve the sensitivity to these objects. Commissioning of
the near-infrared camera and optimizing the AO performance occur in parallel
with ongoing visible-light science programs.


title: Radial excitations of current-carrying vortices

abstract:
  We report on the existence of a new type of cosmic string solutions in the
Witten model with U(1)xU(1) symmetry. These solutions are superconducting with
radially excited condensates that exist for both gauge and ungauged currents.
Our results suggest that these new configurations can be macroscopically
stable, but microscopically unstable to radial perturbations. Nevertheless,
they might have important consequences for the network evolution and particle
emission. We discuss these effects and their possible signatures. We also
comment on analogies with non-relativistic condensed matter systems where these
solutions may be observable.


title: Four dimensional loop-erased random walk

abstract:
  The loop-erased random walk (LERW) in $\mathbb{Z}^4$ is the process obtained
by erasing loops chronologically for simple random walk. We prove that the
escape probability of the LERW renormalized by $(\log n)^{\frac{1}{3}}$
converges almost surely and in $L^{p}$ for all $p>0$. Along the way, we extend
previous results by the first author building on slowly recurrent sets. We
provide two applications for the escape probability. We construct the two-sided
LERW, and we construct a $\pm 1$ spin model coupled with the wired spanning
forests on $\mathbb{Z}^4$ with the bi-Laplacian Gaussian field on
$\mathbb{R}^{4}$ as its scaling limit.


title: StegIbiza: New Method for Information Hiding in Club Music

abstract:
  In this paper a new method for information hiding in club music is
introduced. The method called StegIbiza is based on using the music tempo as a
carrier. The tempo is modulated by hidden messages with a 3-value coding
scheme, which is an adoption of Morse code for StegIbiza. The evaluation of the
system was performed for several music samples (with and without StegIbiza
enabled) on a selected group of testers who had a music background. Finally,
for the worst case scenario, none of them could identify any differences in the
audio with a 1% margin of changed tempo.


title:
Deep Convolutional Neural Networks for Microscopy-Based Point of Care
  Diagnostics

abstract:
  Point of care diagnostics using microscopy and computer vision methods have
been applied to a number of practical problems, and are particularly relevant
to low-income, high disease burden areas. However, this is subject to the
limitations in sensitivity and specificity of the computer vision methods used.
In general, deep learning has recently revolutionised the field of computer
vision, in some cases surpassing human performance for other object recognition
tasks. In this paper, we evaluate the performance of deep convolutional neural
networks on three different microscopy tasks: diagnosis of malaria in thick
blood smears, tuberculosis in sputum samples, and intestinal parasite eggs in
stool samples. In all cases accuracy is very high and substantially better than
an alternative approach more representative of traditional medical imaging
techniques.


title: Bayesian Mendelian Randomization

abstract:
  Our Bayesian approach to Mendelian Randomisation uses multiple instruments to
assess the putative causal effect of an exposure on an outcome. The approach is
robust to violations of the (untestable) Exclusion Restriction condition, and
hence it does not require instruments to be independent of the outcome
conditional on the exposure and on the confounders of the exposure-outcome
relationship. The Bayesian approach offers a rigorous handling of the
uncertainty (e.g. about the estimated instrument-exposure associations),
freedom from asymptotic approximations of the null distribution and the
possibility to elaborate the model in any direction of scientific relevance. We
illustrate the last feature with the aid of a study of the metabolic mediators
of the disease-inducing effects of obesity, where we elaborate the model to
investigate whether the causal effect of interest interacts with a covariate.
The proposed model contains a vector of unidentifiable parameters, $\beta$,
whose $j$th element represents the pleiotropic (i.e., not mediated by the
exposure) component of the association of instrument $j$ with the outcome. We
deal with the incomplete identifiability by assuming that the pleiotropic
effect of some instruments is null, or nearly so, formally by imposing on
$\beta$ Carvalho's horseshoe shrinkage prior, in such a way that different
components of $\beta$ are subjected to different degrees of shrinking,
adaptively and in accord with the compatibility of each individual instrument
with the hypothesis of no pleiotropy. This prior requires a minimal input from
the user. We present the results of a simulation study into the performance of
the proposed method under different types of pleiotropy and sample sizes.
Comparisons with the performance of the weighted median estimator are made.
Choice of the prior and inference via Markov chain Monte Carlo are discussed.


title:
Albanian Sign Language (AlbSL) Number Recognition from Both Hand's
  Gestures Acquired by Kinect Sensors

abstract:
  Albanian Sign Language (AlbSL) is relatively new and until now there doesn't
exist a system that is able to recognize Albanian signs by using natural user
interfaces (NUI). The aim of this paper is to present a real-time gesture
recognition system that is able to automatically recognize number signs for
Albanian Sign Language, captured from signer's both hands. Kinect device is
used to obtain data streams. Every pixel generated from Kinect device contains
depth data information which is used to construct a depth map. Hands
segmentation process is performed by applying a threshold constant to depth
map. In order to differentiate signer's hands a K-means clustering algorithm is
applied to partition pixels into two groups corresponding to each signer's
hands. Centroid distance function is calculated in each hand after extracting
hand's contour pixels. Fourier descriptors, derived form centroid distance is
used as a hand shape representation. For each number gesture there are 15
Fourier descriptors coefficients generated which represent uniquely that
gesture. Every input data is compared against training data set by calculating
Euclidean distance, using Fourier coefficients. Sign with the lowest Euclidean
distance is considered as a match. The system is able to recognize number signs
captured from one hand or both hands. When both signer's hands are used, some
of the methodology processes are executed in parallel in order to improve the
overall performance. The proposed system achieves an accuracy of 91% and is
able to process 55 frames per second.


title:
Existence of weak solutions to an evolutionary model for
  magnetoelasticity

abstract:
  We prove existence of weak solutions to an evolutionary model derived for
magnetoelastic materials. The model is phrased in Eulerian coordinates and
consists in particular of (i) a Navier-Stokes equation that involves magnetic
and elastic terms in the stress tensor obtained by a variational approach, of
(ii) a regularized transport equation for the deformation gradient and of (iii)
the Landau-Lifshitz-Gilbert equation for the dynamics of the magnetization. The
proof is built on a Galerkin method and a fixed-point argument. It is based on
ideas from F.-H. Lin and the third author for systems modeling the flow of
liquid crystals as well as on methods by G. Carbou and P. Fabrie for solutions
of the Landau-Lifshitz equation.


title: OTFS - Orthogonal Time Frequency Space

abstract:
  In this paper we introduce a new 2D modulation technique called OTFS
(Orthogonal Time Frequency & Space) that transforms information carried in the
Delay-Doppler coordinate system to the familiar time-frequency domain utilized
by traditional modulation schemes such as OFDM, CDMA and TDMA. OTFS converts
the fading, time-varying wireless channel into a non-fading, time-independent
interaction revealing the underlying geometry of the wireless channel. In this
new formulation, all QAM symbols experience the same channel and all
Delay-Doppler diversity branches of the channel are coherently combined.
Reference signal multiplexing is done in the time-independent Delay-Doppler
domain, achieving high density pilot packing, which is a crucial requirement
for Massive MIMO. Regardless of the Doppler scenario, OTFS enables approaching
channel capacity through linear scaling of throughput with MIMO order, thus
realizing the full promise of Massive MIMO throughput gains even in challenging
5G deployment settings.


title: Long-duration superluminous supernovae at late times

abstract:
  Nebular-phase observations and spectral models of Type Ic superluminous
supernovae are presented. LSQ14an and SN 2015bn both display late-time spectra
similar to galaxy-subtracted spectra of SN 2007bi, and the class shows strong
similarity with broad-lined Type Ic SNe such as SN 1998bw. Near-infrared
observations of SN 2015bn show a strong Ca II triplet, O I 9263, O I 1.13 um
and Mg I 1.50 um, but no distinct He, Si, or S emission. The high Ca II NIR/[Ca
II] 7291,7323 ratio of ~2 indicates a high electron density of n_e >~ 10^8
cm^{-3}. Spectral models of oxygen-zone emission are investigated to put
constraints on the emitting region. Models require M(O-zone) >~ 10 Msun to
produce enough [O I] 6300,6364 luminosity, irrespective of the powering
situation and the density. The high oxygen-zone mass, supported by high
estimated magnesium masses, points to explosions of massive CO cores, requiring
M_ZAMS >~ 40 Msun. Collisions of pair-instability pulsations do not provide
enough mass to account for the emission. [O II] and [O III] lines emerge
naturally in many models, which strengthens the identification of broad [O II]
7320,7330, [O III] 4363, and [O III] 4959,5007 in some spectra. A small filling
factor f <~ 0.01 for the O/Mg zone is needed to produce enough luminosity in Mg
I] 4571, Mg I 1.504 um, and O I recombination lines, which shows that the
ejecta is clumped. We review the constraints from the nebular spectral
modelling in the context of the various scenarios proposed for superluminous
supernovae.