title: Narumi-Katayama Index of Total Transformation Graphs

abstract:
  The Narumi-Katayama index of a graph was introduced in 1984 for representing
the carbon skeleton of a saturated hydrocarbons and is defined as the product
of degrees of all the vertices of the graph. In this paper, we examine the
Narumi-Katayama index of different total transformation graphs.


title:
Correlated-PCA: Principal Components' Analysis when Data and Noise are
  Correlated

abstract:
  Given a matrix of observed data, Principal Components Analysis (PCA) computes
a small number of orthogonal directions that contain most of its variability.
Provably accurate solutions for PCA have been in use for a long time. However,
to the best of our knowledge, all existing theoretical guarantees for it assume
that the data and the corrupting noise are mutually independent, or at least
uncorrelated. This is valid in practice often, but not always. In this paper,
we study the PCA problem in the setting where the data and noise can be
correlated. Such noise is often also referred to as "data-dependent noise". We
obtain a correctness result for the standard eigenvalue decomposition (EVD)
based solution to PCA under simple assumptions on the data-noise correlation.
We also develop and analyze a generalization of EVD, cluster-EVD, that improves
upon EVD in certain regimes.


title: Optimizing the Production Cost of Minting with Mixed Integer Programming

abstract:
  For central banks, managing the minting is one of the most important task
since a shortage yields negative economic and social impacts, and the budget
committed for minting is one of the largest within the central banks. Hence,
the central bank requires to find the mixture of coins to be produced that
satisfies the demand, inventory and production constraints while minimizing the
cost. We propose a mixed-integer programming model that minimize the cost of
minting by reducing the number of extra-shifts required while fulfilling the
constraints. We also perform a simulation with data of a central bank which
shows that the model reduces in 24\% the cost of extra-shifts used during 21
quarters, compared with the spreadsheet based approach used currently at the
operation.


title:
Perturbativity vs non-perturbativity in QED-effects for H-like atoms
  with $Z\alpha >1$

abstract:
  The behavior of levels near the threshold of the lower continuum in
superheavy H-like atoms with $Z\alpha >1$, caused by the interaction $\Delta
U_{AMM}$ of the electron's magnetic anomaly (AMM) dynamically screened at small
distances $ \ll 1/m$, with the Coulomb field of atomic nucleus is considered by
taking into account the complete dependence of electron's wavefunction (WF) on
$Z\alpha$. It is shown that the calculation of the contribution caused by
$\Delta U_{AMM}$ via both the quark structure and the whole nucleus, considered
as a uniformly charged extended Coulomb source, leads to results, which
coincide within the accepted precision of calculations. It is shown also that
there appears some difference in results between perturbative and
non-perturbative methods of accounting for the contribution from $\Delta
U_{AMM}$ within the corresponding Dirac equation (DE) in favor of the latter.
Moreover, the growth rate of the contribution from $\Delta U_{AMM}$ reaches its
maximum at $ Z \sim 140-150$, while by further increase of $Z$ into the
supercritical region $Z\gg Z_{cr,1}$ the shift of levels caused by $\Delta
U_{AMM}$ near the lower continuum decreases monotonically to zero. The last
result is generalized to the whole self-energy contribution to the shift of
levels and so to the possible behavior of radiative QED-effects with virtual
photon exchange near the lower continuum.


title:
Proton irradiation results for long-wave HgCdTe infrared detector arrays
  for NEOCam

abstract:
  HgCdTe detector arrays with a cutoff wavelength of ~10 ${\mu}$m intended for
the NEOCam space mission were subjected to proton beam irradiation at the
University of California Davis Crocker Nuclear Laboratory. Three arrays were
tested - one with 800 $\mu$m substrate intact, one with 30 $\mu$m substrate,
and one completely substrate-removed. The CdZnTe substrate, on which the HgCdTe
detector is grown, has been shown to produce luminescence in shorter wave
HgCdTe arrays that causes elevated signal in non-hit pixels when subjected to
proton irradiation. This testing was conducted to ascertain whether or not full
substrate removal is necessary. At the dark level of the dewar, we detect no
luminescence in non-hit pixels during proton testing for both the
substrate-removed detector array and the array with 30 ${\mu}$m substrate. The
detector array with full 800 ${\mu}$m substrate exhibited substantial
photocurrent for a flux of 103 protons/cm$^2$-s at a beam energy of 18.1 MeV (~
750 e$^-$/s) and 34.4 MeV ($\sim$ 65 e$^-$/s). For the integrated space-like
ambient proton flux level measured by the Spitzer Space Telescope, the
luminescence would be well below the NEOCam dark current requirement of <200
e$^-$/s, but the pattern of luminescence could be problematic, possibly
complicating calibration.


title:
Uniqueness and Lagrangianity for solutions with lack of integrability of
  the continuity equation

abstract:
  We deal with the uniqueness of distributional solutions to the continuity
equation with a Sobolev vector field and with the property of being a
Lagrangian solution, that means transported by a flow of the associated
ordinary differential equation. We work in a framework with lack of local
integrability of the solution, in which the classical DiPerna-Lions theory of
uniqueness and Lagrangianity of distributional solutions does not apply due to
the insufficient integrability of the commutator. We introduce a general
principle to prove that a solution is Lagrangian: we rely on a disintegration
along the unique flow and on a new directional Lipschitz extension lemma, used
to construct a large class of test functions in the Lagrangian distributional
formulation of the continuity equation.


title: Aleksandrov-Clark theory for the Drury-Arveson space

abstract:
  Recent work has demonstrated that Clark's theory of unitary perturbations of
the backward shift restricted to a deBranges-Rovnyak subspace of Hardy space on
the disk has a natural extension to the several variable setting. In the
several variable case, the appropriate generalization of the Schur class of
contractive analytic functions is the closed unit ball of the Drury-Arveson
multiplier algebra and the Aleksandrov-Clark measures are necessarily promoted
to positive linear functionals on a symmetrized subsystem of the Cuntz-Toeplitz
operator system A + A*, where A is the non-commutative disk algebra. We
continue this program for vector-valued Drury-Arveson space by establishing the
existence of a canonical `tight' extension of any Aleksandrov-Clark map to the
full Cuntz-Toeplitz operator system. We apply this tight extension to
generalize several earlier results and we characterize all extensions of the
Aleksandrov-Clark maps.


title: A remark on the extreme value theory for continued fractions

abstract:
  Let $x$ be a irrational number in the unit interval and denote by its
continued fraction expansion $[a_1(x), a_2(x), \cdots, a_n(x), \cdots]$. For
any $n \geq 1$, write $T_n(x) = \max_{1 \leq k \leq n}\{a_k(x)\}$. We are
interested in the Hausdorff dimension of the fractal set \[ E_\phi = \left\{x
\in (0,1): \lim_{n \to \infty} \frac{T_n(x)}{\phi(n)} =1\right\}, \] where
$\phi$ is a positive function defined on $\mathbb{N}$ with $\phi(n) \to \infty$
as $n \to \infty$. Some partial results have been obtained by Wu and Xu, Liao
and Rams, and Ma. In the present paper, we further study this topic when
$\phi(n)$ tends to infinity with a doubly exponential rate as $n$ goes to
infinity.


title: Extremal multipliers of the Drury-Arveson space

abstract:
  We give a new characterization of the so-called quasi-extreme multipliers of
the Drury-Arveson space $H^2_d$, and show that every quasi-extreme multiplier
is an extreme point of the unit ball of the multiplier algebra of $H^2_d$.


title: Placing Marangoni instabilities under arrest

abstract:
  Soap bubbles occupy the rare position of delighting and fascinating both
young children and scientific minds alike. Sir Isaac Newton, Joseph Plateau,
Carlo Marangoni, and Pierre-Gilles de Gennes, not to mention countless others,
have discovered remarkable results in optics, molecular forces and fluid
dynamics from investigating this seemingly simple system. We present here a
compilation of curiosity-driven experiments that systematically investigate the
surface flows on a rising soap bubble. From childhood experience, we are
familiar with the vibrant colors and mesmerizing display of chaotic flows on
the surface of a soap bubble. These flows arise due to surface tension
gradients, also known as Marangoni flows or instabilities. In Figure 1, we show
the surprising effect of layering multiple instabilities on top of each other,
highlighting that unexpected new phenomena are still waiting to be discovered,
even in the simple soap bubble.


title:
GPU-accelerated Gibbs sampling: a case study of the Horseshoe Probit
  model

abstract:
  Gibbs sampling is a widely used Markov chain Monte Carlo (MCMC) method for
numerically approximating integrals of interest in Bayesian statistics and
other mathematical sciences. Many implementations of MCMC methods do not extend
easily to parallel computing environments, as their inherently sequential
nature incurs a large synchronization cost. In the case study illustrated by
this paper, we show how to do Gibbs sampling in a fully data-parallel manner on
a graphics processing unit, for a large class of exchangeable models that admit
latent variable representations. Our approach takes a systems perspective, with
emphasis placed on efficient use of compute hardware. We demonstrate our method
on a Horseshoe Probit regression model and find that our implementation scales
effectively to thousands of predictors and millions of data points
simultaneously.


title:
Voxel-Based Dose Prediction with Multi-Patient Atlas Selection for
  Automated Radiotherapy Treatment Planning

abstract:
  Automating the radiotherapy treatment planning process is a technically
challenging problem. The majority of automated approaches have focused on
customizing and inferring dose volume objectives to used in plan optimization.
In this work we outline a multi-patient atlas-based dose prediction approach
that learns to predict the dose-per-voxel for a novel patient directly from the
computed tomography (CT) planning scan without the requirement of specifying
any objectives. Our method learns to automatically select the most effective
atlases for a novel patient, and then map the dose from those atlases onto the
novel patient. We extend our previous work to include a conditional random
field for the optimization of a joint distribution prior that matches the
complementary goals of an accurately spatially distributed dose distribution
while still adhering to the desired dose volume histograms. The resulting
distribution can then be used for inverse-planning with a new spatial dose
objective, or to create typical dose volume objectives for the canonical
optimization pipeline. We investigated six treatment sites (633 patients for
training and 113 patients for testing) and evaluated the mean absolute
difference (MAD) in all DVHs for the clinical and predicted dose distribution.
The results on average are favorable in comparison to our previous approach
(1.91 vs 2.57). Comparing our method with and without atlas-selection further
validates that atlas-selection improved dose prediction on average in Whole
Breast (0.64 vs 1.59), Prostate (2.13 vs 4.07), and Rectum (1.46 vs 3.29) while
it is less important in Breast Cavity (0.79 vs 0.92) and Lung (1.33 vs 1.27)
for which there is high conformity and minimal dose shaping. In CNS Brain,
atlas-selection has the potential to be impactful (3.65 vs 5.09), but selecting
the ideal atlas is the most challenging.


title: Consistency constraints for overlapping data clustering

abstract:
  We examine overlapping clustering schemes with functorial constraints, in the
spirit of Carlsson--Memoli. This avoids issues arising from the chaining
required by partition-based methods. Our principal result shows that any
clustering functor is naturally constrained to refine single-linkage clusters
and be refined by maximal-linkage clusters. We work in the context of metric
spaces with non-expansive maps, which is appropriate for modeling data
processing which does not increase information content.


title:
Results of the ASY-EOS experiment at GSI: The symmetry energy at
  suprasaturation density

abstract:
  Directed and elliptic flows of neutrons and light charged particles were
measured for the reaction 197Au+197Au at 400 MeV/nucleon incident energy within
the ASY-EOS experimental campaign at the GSI laboratory. The detection system
consisted of the Large Area Neutron Detector LAND, combined with parts of the
CHIMERA multidetector, of the ALADIN Time-of-flight Wall, and of the
Washington-University Microball detector. The latter three arrays were used for
the event characterization and reaction-plane reconstruction. In addition, an
array of triple telescopes, KRATTA, was used for complementary measurements of
the isotopic composition and flows of light charged particles. From the
comparison of the elliptic flow ratio of neutrons with respect to charged
particles with UrQMD predictions, a value \gamma = 0.72 \pm 0.19 is obtained
for the power-law coefficient describing the density dependence of the
potential part in the parametrization of the symmetry energy. It represents a
new and more stringent constraint for the regime of supra-saturation density
and confirms, with a considerably smaller uncertainty, the moderately soft to
linear density dependence deduced from the earlier FOPI-LAND data. The
densities probed are shown to reach beyond twice saturation.


title: Holomorphic motions for unicritical correspondences

abstract:
  We study quasiconformal deformations and mixing properties of hyperbolic sets
in the family of holomorphic correspondences z^r +c, where r >1 is rational.
Julia sets in this family are projections of Julia sets of holomorphic maps on
C^2, which are skew-products when r is integer, and solenoids when r is
non-integer and c is close to zero. Every hyperbolic Julia set in C^2 moves
holomorphically. The projection determines a branched holomorphic motion with
local (and sometimes global) parameterisations of the plane Julia set by
quasiconformal curves.


title:
Cytoskeletal network morphology regulates intracellular transport
  dynamics

abstract:
  Intracellular transport is essential for maintaining proper cellular function
in most eukaryotic cells, with perturbations in active transport resulting in
several types of disease. Efficient delivery of critical cargos to specific
locations is accomplished through a combination of passive diffusion and active
transport by molecular motors that ballistically move along a network of
cytoskeletal filaments. Although motor-based transport is known to be necessary
to overcome cytoplasmic crowding and the limited range of diffusion within
reasonable time scales, the topological features of the cytoskeletal network
that regulate transport efficiency and robustness have not been established.
Using a continuum diffusion model, we observed that the time required for
cellular transport was minimized when the network was localized near the
nucleus. In simulations that explicitly incorporated network spatial
architectures, total filament mass was the primary driver of network transit
times. However, filament traps that redirect cargo back to the nucleus caused
large variations in network transport. Filament polarity was more important
than filament orientation in reducing average transit times, and transport
properties were optimized in networks with intermediate motor on and off rates.
Our results provide important insights into the functional constraints on
intracellular transport under which cells have evolved cytoskeletal structures,
and have potential applications for enhancing reactions in biomimetic systems
through rational transport network design.


title:
Comparison of dislocation density tensor fields derived from discrete
  dislocation dynamics and crystal plasticity simulations of torsion

abstract:
  The importance of accurate simulation of the plastic deformation of ductile
metals to the design of structures and components is well-known. Many
techniques exist that address the length scales relevant to deformation pro-
cesses, including dislocation dynamics (DD), which models the interaction and
evolution of discrete dislocation line segments, and crystal plasticity (CP),
which incorporates the crystalline nature and restricted motion of dis-
locations into a higher scale continuous field framework. While these two
methods are conceptually related, there have been only nominal efforts focused
on the system-level material response that use DD-generated information to
enhance the fidelity of plasticity models. To ascertain to what degree the
predictions of CP are consistent with those of DD, we compare their global and
microstructural response in a number of deformation modes. After using
nominally homogeneous compression and shear deformation dislocation dynamics
simulations to calibrate crystal plasticity flow rule parameters, we compare
not only the system-level stress-strain response of prismatic wires in torsion
but also the resulting geometrically necessary dislocation density fields. To
establish a connection between explicit description of dislocations and the
continuum assumed with crystal plasticity simulations, we ascertain the minimum
length-scale at which meaningful dislocation density fields appear. Our results
show that, for the case of torsion, the two material models can produce
comparable spatial dislocation density distributions.


title:
The Scalability-Efficiency/Maintainability-Portability Trade-off in
  Simulation Software Engineering: Examples and a Preliminary Systematic
  Literature Review

abstract:
  Large-scale simulations play a central role in science and the industry.
Several challenges occur when building simulation software, because simulations
require complex software developed in a dynamic construction process. That is
why simulation software engineering (SSE) is emerging lately as a research
focus. The dichotomous trade-off between scalability and efficiency (SE) on the
one hand and maintainability and portability (MP) on the other hand is one of
the core challenges. We report on the SE/MP trade-off in the context of an
ongoing systematic literature review (SLR). After characterizing the issue of
the SE/MP trade-off using two examples from our own research, we (1) review the
33 identified articles that assess the trade-off, (2) summarize the proposed
solutions for the trade-off, and (3) discuss the findings for SSE and future
work. Overall, we see evidence for the SE/MP trade-off and first solution
approaches. However, a strong empirical foundation has yet to be established;
general quantitative metrics and methods supporting software developers in
addressing the trade-off have to be developed. We foresee considerable future
work in SSE across scientific communities.


title:
Design of Efficient Convolutional Layers using Single Intra-channel
  Convolution, Topological Subdivisioning and Spatial "Bottleneck" Structure

abstract:
  Deep convolutional neural networks achieve remarkable visual recognition
performance, at the cost of high computational complexity. In this paper, we
have a new design of efficient convolutional layers based on three schemes. The
3D convolution operation in a convolutional layer can be considered as
performing spatial convolution in each channel and linear projection across
channels simultaneously. By unravelling them and arranging the spatial
convolution sequentially, the proposed layer is composed of a single
intra-channel convolution, of which the computation is negligible, and a linear
channel projection. A topological subdivisioning is adopted to reduce the
connection between the input channels and output channels. Additionally, we
also introduce a spatial "bottleneck" structure that utilizes a
convolution-projection-deconvolution pipeline to take advantage of the
correlation between adjacent pixels in the input. Our experiments demonstrate
that the proposed layers remarkably outperform the standard convolutional
layers with regard to accuracy/complexity ratio. Our models achieve similar
accuracy to VGG, ResNet-50, ResNet-101 while requiring 42, 4.5, 6.5 times less
computation respectively.


title:
On generalizations of Fermat curves over finite fields and their
  automorphisms

abstract:
  Let $\mathcal{X}$ be an irreducible algebraic curve defined over a finite
field $\mathbb{F}_q$ of characteristic $p>2$. Assume that the
$\mathbb{F}_q$-automorphism group of $\mathcal{X}$ admits as an automorphism
group the direct product of two cyclic groups $C_m$ and $C_n$ of orders $m$ and
$n$ prime to $p$ such that both quotient curves $\mathcal{X}/C_n$ and
$\mathcal{X}/C_m$ are rational. In this paper, we provide a complete
classification of such curves, as well as a characterization of their full
automorphism groups.


title:
Depth2Action: Exploring Embedded Depth for Large-Scale Action
  Recognition

abstract:
  This paper performs the first investigation into depth for large-scale human
action recognition in video where the depth cues are estimated from the videos
themselves. We develop a new framework called depth2action and experiment
thoroughly into how best to incorporate the depth information. We introduce
spatio-temporal depth normalization (STDN) to enforce temporal consistency in
our estimated depth sequences. We also propose modified depth motion maps
(MDMM) to capture the subtle temporal changes in depth. These two components
significantly improve the action recognition performance. We evaluate our
depth2action framework on three large-scale action recognition video
benchmarks. Our model achieves state-of-the-art performance when combined with
appearance and motion information thus demonstrating that depth2action is
indeed complementary to existing approaches.


title:
A Java Program Generating Barycentric Observer Velocities from JPL
  Ephemerides

abstract:
  This works presents a program which computes velocities of an Earth-bound
observatory in the reference frame of the barycenter of the solar system. It
feeds from ephemerides files of the Jet Propulsion Laboratory to extract the
velocity of the geocenter, optionally with corrections from Earth rotation data
of the International Earth Rotation Service, takes a datum (time and geodetic
location) of the observer as parameters, and processes these data with the
program library of the working group `Standards of Fundamental Astronomy' of
the International Astronomical Union.
  The prospective application of the computed velocities is to subtract their
projection onto a pointing direction from observed velocities in a step of data
reduction of astronomic radial velocities.


title: Partial Identification of Treatment Effects for Generalizability

abstract:
  Recent methods to improve generalizations from nonrandom samples typically
invoke assumptions such as the strong ignorability of sample selection that are
often controversial in practice to derive point estimates. Rather than focus on
the point estimate based inferences, this article considers inferences on
partially identified estimates from fewer and weaker assumptions. We extend
partial identification methods to causal generalization with nonrandom samples
by using a cluster randomized trial in education. Bounds on the population
average treatment effect are derived under four cases, two under no assumptions
on the data, and two that assume bounded sample variation and monotonicity of
response. This approach is amenable to incorporating population data frames to
tighten bounds on the population average treatment effect. Under the
assumptions of bounded sample variation and monotonicity, the interval
estimates of the average treatment effect provide sufficiently informative
bounds to rule out large treatment effects, which are consistent with the point
estimates from the experimental study. This illustrates that partial
identification methods can provide an alternative perspective to causal
generalization in the absence of strong ignorability of sample selection.


title: Intrinsic Light Field Images

abstract:
  We present a method to automatically decompose a light field into its
intrinsic shading and albedo components. Contrary to previous work targeted to
2D single images and videos, a light field is a 4D structure that captures
non-integrated incoming radiance over a discrete angular domain. This higher
dimensionality of the problem renders previous state-of-the-art algorithms
impractical either due to their cost of processing a single 2D slice, or their
inability to enforce proper coherence in additional dimensions. We propose a
new decomposition algorithm that jointly optimizes the whole light field data
for proper angular coherence. For efficiency, we extend Retinex theory, working
on the gradient domain, where new albedo and occlusion terms are introduced.
Results show our method provides 4D intrinsic decompositions difficult to
achieve with previous state-of-the-art algorithms. We further provide a
comprehensive analysis and comparisons with existing intrinsic image/video
decomposition methods on light field images.


title: Nonlinear Response of Bilayer Graphene at Terahertz Frequencies

abstract:
  A density-matrix formalism within the length gauge is developed for the
purpose of calculating the nonlinear response of intrinsic bilayer graphene at
terahertz frequencies. Employing a tight-binding model, we find that interplay
between the interband and intraband dynamics leads to strong harmonic
generation at moderate field amplitudes. Specifically, we find that at low
temperature (10 K), the reflected field of undoped suspended bilayer graphene
exhibits a third harmonic amplitude that is 30% of the fundamental in the
reflected field for an incident 1 THz single-cycle pulse with a field amplitude
of 1.5 kV/cm. More interestingly, we find that as the central frequency of the
incident radiation is increased, the third harmonic amplitude also increases;
reaching a maximum of 53% for an incident frequency of 2 THz and amplitude of
2.5 kV/cm.


title: A Dynamic Uncertainty Principle for Jacobi Operators

abstract:
  We prove that a solution of the Schr\"odinger-type equation
$\mathrm{i}\partial_t u= Hu$, where $H$ is a Jacobi operator with
asymptotically constant coefficients, cannot decay too fast at two different
times unless it is trivial.


title: The Integrated Bispectrum and Beyond

abstract:
  The position-dependent power spectrum has been recently proposed as a
descriptor of gravitationally induced non-Gaussianity in galaxy clustering, as
it is sensitive to the "soft limit" of the bispectrum (i.e. when one of the
wave number tends to zero). We generalise this concept to higher order and
clarify their relationship to other known statistics such as the skew-spectrum,
the kurt-spectra and their real-space counterparts the cumulants correlators.
Using the {\em Hierarchical Ansatz} (HA) as a toy model for the higher order
correlation hierarchy, we show how in the soft limit, polyspectra at a given
order can be identified with lower order polyspectra with the same geometrical
dependence but with {\em renormalised} amplitudes expressed in terms of
amplitudes of the original polyspectra. We extend the concept of
position-dependent bispectrum to bispectrum of the divergence of the velocity
field $\Theta$ and mixed multispectra involving $\delta$ and $\Theta$ in the 3D
perturbative regime. To quantify the effects of transients in numerical
simulations, we also present results for lowest order in Lagrangian
perturbation theory (LPT) or the Zel'dovich approximation (ZA). Finally, we
discuss how to extend the position-dependent spectrum concept to encompass
cross-spectra. And finally study the application of this concept to two
dimensions (2D), for projected galaxy maps, convergence $\kappa$ maps from
weak-lensing surveys or maps of CMB secondaries e.g. the frequency cleaned $y$
- parameter maps of thermal Sunyaev-Zel'dovich (tSZ) effect from CMB surveys.


title:
Topological Visualisation techniques for the understanding of Lattice
  Quantum Chromodynamics (LQCD) simulations

abstract:
  The use of topology for visualisation applications has become increasingly
popular due to its ability to summarise data at a high level. Criticalities in
scalar field data are used by visualisation methods such as the Reeb graph and
contour trees to present topological structure in simple graph based formats.
These techniques can be used to segment the input field, recognising the
boundaries between multiple objects, allowing whole contour meshes to be seeded
as separate objects. In this paper we demonstrate the use of topology based
techniques when applied to theoretical physics data generated from Quantum
Chromodynamics simulations, which due to its structure complicates their use.
We also discuss how the output of algorithms involved in topological
visualisation can be used by physicists to further their understanding of
Quantum Chromodynamics.


title:
ICE-based Custom Full-Mesh Network for the CHIME High Bandwidth Radio
  Astronomy Correlator

abstract:
  New generation radio interferometers encode signals from thousands of antenna
feeds across large bandwidth. Channelizing and correlating this data requires
networking capabilities that can handle unprecedented data rates with
reasonable cost. The Canadian Hydrogen Intensity Mapping Experiment (CHIME)
correlator processes 8-bits from N=2048 digitizer inputs across 400~MHz of
bandwidth. Measured in $N^2~\times $ bandwidth, it is the largest radio
correlator that has been built. Its digital back-end must exchange and
reorganize the 6.6~terabit/s produced by its 128 digitizing and channelizing
nodes, and feed it to the 256-node spatial correlator in a way that each node
obtains data from all digitizer inputs but across a small fraction of the
bandwidth (i.e. `corner-turn'). In order to maximize performance and
reliability of the corner-turn system while minimizing cost, a custom
networking solution has been implemented. The system makes use of Field
Programmable Gate Array (FPGA) transceivers to implement direct, passive,
full-mesh, high speed serial connections between sixteen circuit boards in a
crate, to exchange data between crates, and to offload the data to a cluster of
256 graphics processing unit (GPU) nodes using standard 10~Gbit/s Ethernet
links. The GPU nodes complete the corner-turn by combining data from all crates
and then computing visibilities. Eye diagrams and frame error counters confirm
error-free operation of the corner-turn network in both the currently operating
CHIME Pathfinder telescope (a prototype for the full CHIME telescope) and a
representative fraction of the full CHIME hardware providing an end-to-end
system validation.
  An analysis of an equivalent corner-turn system built with Ethernet switches
instead of custom passive data links is provided.


title: Anomaly detection and classification for streaming data using PDEs

abstract:
  Nondominated sorting, also called Pareto Depth Analysis (PDA), is widely used
in multi-objective optimization and has recently found important applications
in multi-criteria anomaly detection. Recently, a partial differential equation
(PDE) continuum limit was discovered for nondominated sorting leading to a very
fast approximate sorting algorithm called PDE-based ranking. We propose in this
paper a fast real-time streaming version of the PDA algorithm for anomaly
detection that exploits the computational advantages of PDE continuum limits.
Furthermore, we derive new PDE continuum limits for sorting points within their
nondominated layers and show how the new PDEs can be used to classify anomalies
based on which criterion was more significantly violated. We also prove
statistical convergence rates for PDE-based ranking, and present the results of
numerical experiments with both synthetic and real data.


title: Experimentally superposing two pure states with partial prior knowledge

abstract:
  Superposition, arguably the most fundamental property of quantum mechanics,
lies at the heart of quantum information science. However, how to create the
superposition of any two unknown pure states remains as a daunting challenge.
Recently, it is proved that such a quantum protocol does not exist if the two
input states are completely unknown, whereas a probabilistic protocol is still
available with some prior knowledge about the input states [M. Oszmaniec
\emph{et al.}, Phys. Rev. Lett. 116, 110403 (2016)]. The knowledge is that both
of the two input states have nonzero overlaps with some given referential
state. In this work, we experimentally realize the probabilistic protocol of
superposing two pure states in a three-qubit nuclear magnetic resonance system.
We demonstrate the feasibility of the protocol by preparing a families of input
states, and the average fidelity between the prepared state and expected
superposition state is over 99%. Moreover, we experimentally illustrate the
limitation of the protocol that it is likely to fail or yields very low
fidelity, if the nonzero overlaps are approaching zero. Our experimental
implementation can be extended to more complex situations and other quantum
systems.


title: Majorization in C*-algebras

abstract:
  We investigate the closed convex hull of unitary orbits of selfadjoint
elements in arbitrary unital C*-algebras. Using a notion of majorization
against unbounded traces, a characterization of these closed convex hulls is
obtained. Furthermore, for C*-algebras satisfying Blackadar's strict comparison
of positive elements by traces or for collections of C*-algebras with a uniform
bound on their nuclear dimension, an upper bound for the number of unitary
conjugates in a convex combination required to approximate an element in the
closed convex hull within a given error is shown to exist. This property,
however, fails for certain "badly behaved" simple nuclear C*-algebras.


title:
Planck Lensing and Cosmic Infrared Background Cross-Correlation with
  Fermi-LAT: Tracing Dark Matter Signals in the Gamma-Ray Background

abstract:
  The extragalactic $\gamma$-ray background and its spatial anisotropy could
potentially contain a signature of dark matter (DM) annihilation or particle
decay. Astrophysical foregrounds, such as blazars and star-forming galaxies
(SFGs), however, dominate the $\gamma$-ray background, precluding an easy
detection of the signal associated with the DM annihilation or decay in the
background intensity spectrum. The DM imprint on the $\gamma$-ray background is
expected to be correlated with large-scale structure tracers. In some cases,
such a cross-correlation is even expected to have a higher signal-to-noise
ratio than the auto-correlation. One reliable tracer of the DM distribution in
the large-scale structure is lensing of the cosmic microwave background (CMB),
and the cosmic infrared background (CIB) is a reliable tracer of SFGs. We
analyze Fermi-LAT data taken over 92 months and study the cross-correlation
with Planck CMB lensing, Planck CIB, and Fermi-$\gamma$ maps. We put upper
limits on the DM annihilation cross-section from the cross-power spectra with
the $\gamma$-ray background anisotropies. The unbiased power spectrum
estimation is validated with simulations that include cross-correlated signals.
We also provide a set of systematic tests and show that no significant
contaminations are found for the measurements presented here. Using
$\gamma$-ray background map from data gathered over 92 months, we find the best
constraint on the DM annihilation with a $1\sigma$ confidence level upper limit
of $10^{-25}$-$10^{-24}$ cm$^{3}$ s$^{-1}$, when the mass of DM particles is
between 20 and 100 GeV.


title:
Formation and interaction mechanisms of dipolar dislocation loops in fcc
  metals

abstract:
  Dipolar dislocation loops, prevalent in fcc metals, are widely recognized as
controlling many physical aspects of plastic deformation. We present results of
3D dislocation dynamics simulations that shed light on the mechanisms of their
formation, motion, interactions, and large-scale patterning. We identify two
main formation mechanisms, enabled by cross-slip, and show that arrays of
dipoles can be easily formed as a result of the interaction between glide screw
dislocations. We present a systematic analysis of the spectrum of possible
junctions that can form as a result of mutual interaction between dipoles, and
between dipoles and glide dislocations. We show that fully immobile dislocation
segments arise in particular cases of these interactions, leading to hardening
and Frank-Read type sources. We reveal that the collective motion of dipolar
loop arrays can be induced by glide dislocations in the channels of Persistent
Slip Bands (PSB), and result in their clustering within PSB channel walls. An
efficient tripolar drag mechanism is found to contribute to the clustering of
dipolar loops near channel walls.


title:
The JCMT and Herschel Gould Belt Surveys: A comparison of SCUBA-2 and
  Herschel data of dense cores in the Taurus dark cloud L1495

abstract:
  We present a comparison of SCUBA-2 850-$\mu$m and Herschel 70--500-$\mu$m
observations of the L1495 filament in the Taurus Molecular Cloud with the goal
of characterising the SCUBA-2 Gould Belt Survey (GBS) data set. We identify and
characterise starless cores in three data sets: SCUBA-2 850-$\mu$m, Herschel
250-$\mu$m, and Herschel 250-$\mu$m spatially filtered to mimic the SCUBA-2
data. SCUBA-2 detects only the highest-surface-brightness sources, principally
detecting protostellar sources and starless cores embedded in filaments, while
Herschel is sensitive to most of the cloud structure, including extended
low-surface-brightness emission. Herschel detects considerably more sources
than SCUBA-2 even after spatial filtering. We investigate which properties of a
starless core detected by Herschel determine its detectability by SCUBA-2, and
find that they are the core's temperature and column density (for given dust
properties). For similar-temperature cores, such as those seen in L1495, the
surface brightnesses of the cores are determined by their column densities,
with the highest-column-density cores being detected by SCUBA-2. For roughly
spherical geometries, column density corresponds to volume density, and so
SCUBA-2 selects the densest cores from a population at a given temperature.
This selection effect, which we quantify as a function of distance, makes
SCUBA-2 ideal for identifying those cores in Herschel catalogues that are
closest to forming stars. Our results can now be used by anyone wishing to use
the SCUBA-2 GBS data set.


title: Neutrino assisted GUT baryogenesis - revisited

abstract:
  Many GUT models conserve the difference between the baryon and lepton number,
$B-L$. These models can create baryon and lepton asymmetries from heavy Higgs
or gauge boson decays with $B+L \neq 0$ but with $B-L=0$. Since the sphaleron
processes violate $B+L$, such GUT-generated asymmetries will finally be washed
out completely, making GUT baryogenesis scenarios incapable of reproducing the
observed baryon asymmetry of the Universe. In this work, we revisit the idea to
revive GUT baryogenesis, proposed by Fukugita and Yanagida, where right-handed
neutrinos erase the lepton asymmetry before the sphaleron processes can
significantly wash out the original $B+L$ asymmetry, and in this way one can
prevent a total washout of the initial baryon asymmetry. By solving the
Boltzmann equations numerically for baryon and lepton asymmetries in a
simplified 1+1 flavor scenario, we can confirm the results of the original
work. We further generalize the analysis to a more realistic scenario of three
active and two right-handed neutrinos to highlight flavor effects of the
right-handed neutrinos. Large regions in the parameter space of the Yukawa
coupling and the right-handed neutrino mass featuring successful baryogenesis
are identified.


title:
Polynomial Representations of Threshold Functions and Algorithmic
  Applications

abstract:
  We design new polynomials for representing threshold functions in three
different regimes: probabilistic polynomials of low degree, which need far less
randomness than previous constructions, polynomial threshold functions (PTFs)
with "nice" threshold behavior and degree almost as low as the probabilistic
polynomials, and a new notion of probabilistic PTFs where we combine the above
techniques to achieve even lower degree with similar "nice" threshold behavior.
Utilizing these polynomial constructions, we design faster algorithms for a
variety of problems:
  $\bullet$ Offline Hamming Nearest (and Furthest) Neighbors: Given $n$ red and
$n$ blue points in $d$-dimensional Hamming space for $d=c\log n$, we can find
an (exact) nearest (or furthest) blue neighbor for every red point in
randomized time $n^{2-1/O(\sqrt{c}\log^{2/3}c)}$ or deterministic time
$n^{2-1/O(c\log^2c)}$. These also lead to faster MAX-SAT algorithms for sparse
CNFs.
  $\bullet$ Offline Approximate Nearest (and Furthest) Neighbors: Given $n$ red
and $n$ blue points in $d$-dimensional $\ell_1$ or Euclidean space, we can find
a $(1+\epsilon)$-approximate nearest (or furthest) blue neighbor for each red
point in randomized time near
$dn+n^{2-\Omega(\epsilon^{1/3}/\log(1/\epsilon))}$.
  $\bullet$ SAT Algorithms and Lower Bounds for Circuits With Linear Threshold
Functions: We give a satisfiability algorithm for $AC^0[m]\circ LTF\circ LTF$
circuits with a subquadratic number of linear threshold gates on the bottom
layer, and a subexponential number of gates on the other layers, that runs in
deterministic $2^{n-n^\epsilon}$ time. This also implies new circuit lower
bounds for threshold circuits. We also give a randomized
$2^{n-n^\epsilon}$-time SAT algorithm for subexponential-size $MAJ\circ
AC^0\circ LTF\circ AC^0\circ LTF$ circuits, where the top $MAJ$ gate and middle
$LTF$ gates have $O(n^{6/5-\delta})$ fan-in.


title: Galaxy collisions as a mechanism of ultra diffuse galaxy (UDG) formation

abstract:
  We suggest a possible mechanism of ultra diffuse galaxy formation: the UDGs
may occur as a result of a central collision of galaxies. If the galaxies are
young and contain a lot of gas, the collision may kick all the gas off the
systems and thus strongly suppress any further star formation. As a result, the
galaxies now have a very low surface brightness and other properties typical of
the ultra diffuse galaxies. We use the Coma cluster (where numerous UDGs were
recently discovered) to test the efficiency of the process. The mechanism works
very well and can transform a significant fraction of the cluster population
into ultra diffuse galaxies. The UDGs formed by the process concentrate towards
the center of the cluster, and their globular cluster systems remain undamaged,
in accordance with observational results. The projected surface density of UDGs
in the cluster may help us to recognize the mechanism of UDG formation, or
clarify relative contributions of several possible competitive mechanisms at
work.


title: A local theory for Mott-Anderson localization

abstract:
  The paramagnetic metallic phase of the Anderson-Hubbard model (AHM) is
investigated using a non-perturbative local moment approach within the
framework of dynamical mean field theory with a typical medium. Our focus is on
the breakdown of the metallic phase near the metal-insulators transition as
seen in the single-particle spectra, scattering rates and the associated
distribution of Kondo scales. We demonstrate the emergence of a universal,
underlying low energy scale, $T_K^{peak}$. This lies close to the peak of the
distribution of Kondo scales obtained within the metallic phase of the
paramagnetic AHM. Spectral dynamics for energies, $\omega\lesssim T_K^{peak}$
display Fermi liquid universality crossing over to an incoherent universal
dynamics for $\omega\gg T_K^{peak}$ in the scaling regime. Such universal
dynamics indicate that within a local theory the low to moderately low energy
physics is governed by an effective, {\it disorder renormalised} Kondo
screening.


title:
From pQCD to neutron stars: matching equations of state to constrain
  global star properties

abstract:
  The equation of state (EoS) of quantum chromodynamics (QCD) at zero
temperature can be calculated in two different perturbative regimes: for small
values of the baryon chemical potential $\mu$, one may use chiral perturbation
theory (ChEFT); and for large values of $\mu$, one may use perturbative QCD
(pQCD). There is, however, a gap for $\mu \in (0.97\text{ GeV},\, 2.6\text{
GeV})$, where these theories becomes non-perturbative, and where there is
currently no known microscopic description of QCD matter. Unfortunately, this
interval obscures the values of $\mu$ found within the cores of neutron stars
(NSs).
  In this thesis, we argue that thermodynamic matching of the ChEFT and pQCD
EoSs is a legitimate way to obtain quantitative constraints on the
non-pertubative QCD EoS. Moreover, we argue that this method is effective,
verifiable, and systematically improvable. First, we carry out a simplified
matching procedure in QCD-like theories that can be simulated on the lattice
without a sign problem. Our calculated pressure band serves as a prediction for
lattice-QCD practitioners and will allow them to verify or refute the
simplified procedure. Second, we apply the state-of-the-art matched EoS of
Kurkela et al. (2014) to rotating NSs. This allows us to obtain bounds on
observable NS properties, as well as point towards future observations that
would more tightly constrain the current state-of-the-art EoS band. Finally, as
evidence of the ability to improve the procedure, we carry out calculations in
pQCD to improve the zero-temperature pressure. We calculate the full
$\mathcal{O}(g^{6} \ln^{2} g)$ contribution to the pQCD pressure for $n_{f}$
massless quarks, as well as a significant portion of the $\mathcal{O}(g^{6} \ln
g)$ piece and even some of the $\mathcal{O}(g^{6})$ piece.


title:
Generating exact solutions to Einstein's equation using linearized
  approximations

abstract:
  We show that certain solutions to the linearized Einstein equation can---by
the application of a particular type of linearized gauge transformation---be
straightforwardly transformed into solutions of the exact Einstein equation. In
cases with nontrivial matter content, the exact stress-energy tensor of the
transformed metric has the same eigenvalues and eigenvectors as the linearized
stress-energy tensor of the initial approximation. When our gauge exists, the
tensorial structure of transformed metric perturbations identically eliminates
all nonlinearities in Einstein's equation. As examples, we derive the exact
Kerr and gravitational plane wave metrics from standard harmonic-gauge
approximations.


title:
High-precision quadrupole moment reveals significant intruder component
  in 33Al20 ground state

abstract:
  The electric quadrupole moment of the 33Al20 ground state, located at the
border of the island of inversion, was obtained using continuous-beam
beta-detected nuclear quadrupole resonance (beta-NQR). From the measured
quadrupole coupling constant Q = 2.31(4) MHz in an alpha-Al2O3 crystal, a
precise value for the electric quadrupole moment is extracted: Qs= 141(3) mb. A
comparison with large-scale shell model calculations shows that 33Al has at
least 50% intruder configurations in the ground state wave function, favoring
the excitation of two neutrons across the N = 20 shell gap. 33Al therefore
clearly marks the gradual transition north of the deformed Na and Mg nuclei
towards the normal Z>14 isotopes.


title: Multi-way Monte Carlo Method for Linear Systems

abstract:
  We study the Monte Carlo method for solving a linear system of the form $x =
H x + b$. A sufficient condition for the method to work is $\| H \| < 1$, which
greatly limits the usability of this method. We improve this condition by
proposing a new multi-way Markov random walk, which is a generalization of the
standard Markov random walk. Under our new framework we prove that the
necessary and sufficient condition for our method to work is the spectral
radius $\rho(H^{+}) < 1$, which is a weaker requirement than $\| H \| < 1$. In
addition to solving more problems, our new method can work faster than the
standard algorithm. In numerical experiments on both synthetic and real world
matrices, we demonstrate the effectiveness of our new method.


title: Computational Soundness for Dalvik Bytecode

abstract:
  Automatically analyzing information flow within Android applications that
rely on cryptographic operations with their computational security guarantees
imposes formidable challenges that existing approaches for understanding an
app's behavior struggle to meet. These approaches do not distinguish
cryptographic and non-cryptographic operations, and hence do not account for
cryptographic protections: f(m) is considered sensitive for a sensitive message
m irrespective of potential secrecy properties offered by a cryptographic
operation f. These approaches consequently provide a safe approximation of the
app's behavior, but they mistakenly classify a large fraction of apps as
potentially insecure and consequently yield overly pessimistic results.
  In this paper, we show how cryptographic operations can be faithfully
included into existing approaches for automated app analysis. To this end, we
first show how cryptographic operations can be expressed as symbolic
abstractions within the comprehensive Dalvik bytecode language. These
abstractions are accessible to automated analysis, and they can be conveniently
added to existing app analysis tools using minor changes in their semantics.
Second, we show that our abstractions are faithful by providing the first
computational soundness result for Dalvik bytecode, i.e., the absence of
attacks against our symbolically abstracted program entails the absence of any
attacks against a suitable cryptographic program realization. We cast our
computational soundness result in the CoSP framework, which makes the result
modular and composable.


title:
Deep Convolutional Neural Networks and Data Augmentation for
  Environmental Sound Classification

abstract:
  The ability of deep convolutional neural networks (CNN) to learn
discriminative spectro-temporal patterns makes them well suited to
environmental sound classification. However, the relative scarcity of labeled
data has impeded the exploitation of this family of high-capacity models. This
study has two primary contributions: first, we propose a deep convolutional
neural network architecture for environmental sound classification. Second, we
propose the use of audio data augmentation for overcoming the problem of data
scarcity and explore the influence of different augmentations on the
performance of the proposed CNN architecture. Combined with data augmentation,
the proposed model produces state-of-the-art results for environmental sound
classification. We show that the improved performance stems from the
combination of a deep, high-capacity model and an augmented training set: this
combination outperforms both the proposed CNN without augmentation and a
"shallow" dictionary learning model with augmentation. Finally, we examine the
influence of each augmentation on the model's classification accuracy for each
class, and observe that the accuracy for each class is influenced differently
by each augmentation, suggesting that the performance of the model could be
improved further by applying class-conditional data augmentation.


title:
Photon-blockade induced photon anti-bunching in photosynthetic Antennas
  with cyclic structures

abstract:
  One of the important nonclassical effects in quantum optics is the
anti-bunching, which has been observed in a large class of physical systems -
including light-harvesting antennas with cyclic structures. The units of the
ring couple with adjacent ones through dipole-dipole interactions. We show how
this strong dipole-dipole interaction leads to photon-blockade resulting in the
suppression of double excitation pathway and anti-bunching in photosynthesis
systems. The robustness of the photon blockade is demonstrated against the
disorder in the ring structures. We hypothesis that the effect may be utilized
by light-harvesting systems to avoid damages from excess energy.


title: Electron Accumulation Layer in Ultrastrong Magnetic Field

abstract:
  When a three-dimensional electron gas is subjected to a very strong magnetic
field, it can reach a quasi-one-dimensional state in which all electrons occupy
the lowest Landau level. This state is referred to as the extreme quantum limit
(EQL) and has been studied in the physics of pulsars and bulk semiconductors.
Here we present a theory of the EQL phase in electron accumulation layers
created by an external electric field $E$ at the surface of a semiconductor
with a large Bohr radius such as InSb, PbTe, SrTiO$_3$ (STO), and particularly
in the LaAlO$_3$/SrTiO$_3$ (LAO/STO) heterostructure. The phase diagram of the
electron gas in the plane of the magnetic field strength and the electron
surface concentration is found for different orientations of the magnetic
field. We find that in addition to the quasi-classical metallic phase (M),
there is a metallic EQL phase, as well as an insulating Wigner crystal state
(WC). Within the EQL phase, the Thomas-Fermi approximation is used to find the
electron density and the electrostatic potential profiles of the accumulation
layer. Additionally, the quantum capacitance for each phase is calculated as a
tool for experimental study of these phase diagrams.


title:
Infill Optimization for Additive Manufacturing -- Approaching Bone-like
  Porous Structures

abstract:
  Porous structures such as trabecular bone are widely seen in nature. These
structures exhibit superior mechanical properties whilst being lightweight. In
this paper, we present a method to generate bone-like porous structures as
lightweight infill for additive manufacturing. Our method builds upon and
extends voxel-wise topology optimization. In particular, for the purpose of
generating sparse yet stable structures distributed in the interior of a given
shape, we propose upper bounds on the localized material volume in the
proximity of each voxel in the design domain. We then aggregate the local
per-voxel constraints by their p-norm into an equivalent global constraint, in
order to facilitate an efficient optimization process. Implemented on a
high-resolution topology optimization framework, our results demonstrate
mechanically optimized, detailed porous structures which mimic those found in
nature. We further show variants of the optimized structures subject to
different design specifications, and analyze the optimality and robustness of
the obtained structures.


title:
Van Vleck correction generalization for complex correlators with
  multilevel quantization

abstract:
  Remote sensing with phased antenna arrays is based on measurement of the
cross-correlations between the signals from each antenna pair. Digital
correlators have systematic errors due to the quantization losses. The
correlation errors allow substantial abatement based on the assumption that the
analog signals are stochastic processes sampled from a statistical distribution
(usually the Gaussian). The correlation correction technique is named after Van
Vleck who was the first to apply it to two-level clipping quantizers. The
correction is especially important for high correlation levels, e.g. in studies
of solar radio emissions. We offer a generalized method that for every antenna
pair inputs the quantized signals' covariance and standard deviations, and
outputs high-precision estimates of the analog correlation. Although
correlation correction methods have been extensively investigated in the past,
there are several problems that, as far as we know, have not been published
yet. We consider a very general quantization scheme with arbitrary set of
transition thresholds and output levels, and our correction method is designed
for correlations obtained from signals with generally unequal standard
deviations. We also provide a method for estimation of the analog standard
deviation from the quantized one for subsequent use in the correlation
correction. We apply the correction to the the complex-valued analytic signals,
overwhelmingly used in modern remote sensing systems with arrays of antennas.
The approach is valid not only for analytic signals with the imaginary part
being the Hilbert transform of the real one, but also for more general,
circularly symmetric complex processes whose real and imaginary parts may have
arbitrary relationships to each other. This work was motivated by the need for
greater precision in analysis of data from the Murchison Widefield Array (MWA).


title:
Numerical calculation of the Casimir-Polder interaction between a
  graphene sheet with vacancies and an atom

abstract:
  In this work the Casimir{Polder interaction energy between a rubidium atom
and a disordered graphene sheet is investigated beyond the Dirac cone
approximation by means of accurate real-space calculations. As a model of
defected graphene, we consider a tight-binding model of \Pi-electrons on a
honeycomb lattice with a small concentration of point defects. The optical
response of the graphene sheet is evaluated with full spectral resolution by
means of exact Chebyshev polynomial expansions of the Kubo formula in large
lattices with in excess of ten million atoms. At low temperatures, the optical
response of defected graphene is found to display two qualitatively distinct
behavior with a clear transition around non-zero Fermi energy, \mu~\mu*. In the
vicinity of the Dirac point, the imaginary part of optical conductivity is
negative for low frequencies while the real part is strongly suppressed. On the
other hand, for high doping, it has the same features found in the Drude model
within the Dirac cone approximation, namely, a Drude peak at small frequencies
and a change of sign in the imaginary part above the interband threshold \omega
> 2\mu. These characteristics translate into a non-monotonic behavior of the
Casimir{Polder interaction energy with very small variation with doping in the
vicinity of the neutrality point while having the same form of the interaction
calculated with Drude's model at high electronic density.


title: Star-galaxy Classification Using Deep Convolutional Neural Networks

abstract:
  Most existing star-galaxy classifiers use the reduced summary information
from catalogs, requiring careful feature extraction and selection. The latest
advances in machine learning that use deep convolutional neural networks allow
a machine to automatically learn the features directly from data, minimizing
the need for input from human experts. We present a star-galaxy classification
framework that uses deep convolutional neural networks (ConvNets) directly on
the reduced, calibrated pixel values. Using data from the Sloan Digital Sky
Survey (SDSS) and the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS),
we demonstrate that ConvNets are able to produce accurate and well-calibrated
probabilistic classifications that are competitive with conventional machine
learning techniques. Future advances in deep learning may bring more success
with current and forthcoming photometric surveys, such as the Dark Energy
Survey (DES) and the Large Synoptic Survey Telescope (LSST), because deep
neural networks require very little, manual feature engineering.

categories: astro-ph.IM astro-ph.CO astro-ph.GA cs.CV


title:
Coarse-graining strategy for molecular pair interactions: A reaction
  coordinate study for two- and three-dimensional systems

abstract:
  We investigate and provide optimal sets of reaction coordinates for mixed
pairs of molecules displaying polar, uniaxial, or spherical symmetry in two and
three dimensions. These coordinates are non-redundant, i.e., they implicitly
involve the molecules' symmetries. By tabulating pair interactions in these
coordinates, resulting tables are thus minimal in length and require a minimal
memory space. The intended fields of application are computer simulations of
large ensembles of molecules or colloids with rather complex interactions in a
fluid or liquid crystalline phase at low densities. Using effective
interactions directly in the form of tables can help bridging the time and
length scales without introducing errors stemming from any modeling procedure.
Finally, we outline an exemplary computational methodology for gaining an
effective pair potential in these coordinates, based on the Boltzmann inversion
principle, by providing a step-by-step recipe.


title: Ricci Curvature and Bochner Formulas for Martingales

abstract:
  We generalize the classical Bochner formula for the heat flow on M to
martingales on the path space PM, and develop a formalism to compute evolution
equations for martingales on path space. We see that our Bochner formula on PM
is related to two sided bounds on Ricci curvature in much the same manner that
the classical Bochner formula on M is related to lower bounds on Ricci
curvature. Using this formalism, we obtain new characterizations of bounded
Ricci curvature, new gradient estimates for martingales on path space, new
Hessian estimates for martingales on path space, and streamlined proofs of the
previous characterizations of bounded Ricci curvature of the second author
(arXiv:1306.6512).


title: Ponderomotive Acceleration in Coronal Loops

abstract:
  Ponderomotive acceleration has been asserted to be a cause of the First
Ionization Potential (FIP) effect, the by now well known enhancement in
abundance by a factor of 3-4 over photospheric values of elements in the solar
corona with FIP less than about 10 eV. It is shown here by means of numerical
simulations that ponderomotive acceleration occurs in solar coronal loops, with
the appropriate magnitude and direction, as a "byproduct" of coronal heating.
The numerical simulations are performed with the HYPERION code, which solves
the fully compressible three-dimensional magnetohydrodynamic equations
including nonlinear thermal conduction and optically thin radiation. Numerical
simulations of a coronal loops with an axial magnetic field from 0.005 Teslas
to 0.02 Teslas and lengths from 25000 km to 75000 km are presented. In the
simulations the footpoints of the axial loop magnetic field are convected by
random, large-scale motions. There is a continuous formation and dissipation of
field-aligned current sheets which act to heat the loop. As a consequence of
coronal magnetic reconnection, small scale, high speed jets form. The familiar
vortex quadrupoles form at reconnection sites. Between the magnetic footpoints
and the corona the reconnection flow merges with the boundary flow. It is in
this region that the ponderomotive acceleration occurs. Mirroring the character
of the coronal reconnection, the ponderomotive acceleration is also found to be
intermittent.


title:
Degenerations of Kahlerian K3 surfaces with finite symplectic
  automorphism groups. III

abstract:
  Similarly to our papers I and II on the subject (see arXiv:1403.6061 and
arXiv:1504.00326), we classify degenerations of codimension 2 and higher of
Kahlerian K3 surfaces with finite symplectic automorphism groups. In parts I
and II, it was done for the codimension one.


title: A Geometric Framework for Convolutional Neural Networks

abstract:
  In this paper, a geometric framework for neural networks is proposed. This
framework uses the inner product space structure underlying the parameter set
to perform gradient descent not in a component-based form, but in a
coordinate-free manner. Convolutional neural networks are described in this
framework in a compact form, with the gradients of standard --- and
higher-order --- loss functions calculated for each layer of the network. This
approach can be applied to other network structures and provides a basis on
which to create new networks.


title:
Two-electron quantum dot model revisited: bound states and other
  analytical and numerical solutions

abstract:
  The model of a two-electron quantum dot, confined to move in a two
dimensional flat space, is revisited. Generally, it is argued that the
solutions of this model obtained by solving a biconfluent Heun equation have
some limitations. In particular, some corrections are also made in previous
theoretical calculations. The corrected polynomial solutions are confronted
with numerical calculations based on the Numerov method, in a good agreement
between both. Then, new solutions considering the $1/r$ and $\ln r$
Coulombian-like potentials in (1+2)D, not yet obtained, are discussed
numerically. In particular, we are able to calculate the quantum dot
eigenfunctions for a much larger spectrum of external harmonic frequencies as
compared to previous results. Also the existence of bound states for such
planar system in the case $l=0$ is predicted and the respective eigenvalues are
determined.


title:
Constraining the Higgs couplings to up and down quarks using production
  kinematics at the CERN Large Hadron Collider

abstract:
  We study the prospects for constraining the Higgs boson's couplings to up and
down quarks using kinematic distributions in Higgs production at the CERN Large
Hadron Collider. We find that the Higgs $p_T$ distribution can be used to
constrain these couplings with precision competitive to other proposed
techniques. With 3000 fb$^{-1}$ of data at 13 TeV in the four-lepton decay
channel, we find $-0.73 \lesssim \bar{\kappa}_u \lesssim 0.33$ and $-0.88
\lesssim \bar{\kappa}_d \lesssim 0.32$, where $\bar{\kappa}_q = (m_q/m_b)
\kappa_q$ is a scaling factor that modifies the $q$ quark Yukawa coupling
relative to the Standard Model bottom quark Yukawa coupling. The sensitivity
may be improved by including additional Higgs decay channels.


title: Two and Three-body Contacts in the Unitary Bose Gas

abstract:
  In many-body systems governed by pairwise contact interactions, a wide range
of observables is linked by a single parameter, the two-body contact, which
quantifies two-particle correlations. This profound insight has transformed our
understanding of strongly interacting Fermi gases. Here, using Ramsey
interferometry, we study coherent evolution of the resonantly interacting Bose
gas, and show that it cannot be explained by only pairwise correlations. Our
experiments reveal the crucial role of three-body correlations arising from
Efimov physics, and provide a direct measurement of the associated three-body
contact.


title:
Hadronic matter at the edge: A survey of some theoretical approaches to
  the physics of the QCD phase diagram

abstract:
  In the past few years a wealth of high quality data has made possible to test
current theoretical ideas about the properties of hadrons subject to extreme
conditions of density and temperature. The relativistic heavy-ion program
carried out at the CERN-SPS and under development at the BNL-RHIC and CERN-LHC
has provided results that probe the evolution of collisions of hadronic matter
at high energies from the initially large density to the late dilute stages. In
addition, QCD on the lattice has produced results complementing these findings
with first principles calculations for observables in a regime where
perturbative techniques cannot describe the nature of strongly coupled systems.
This work aims to review some recent developments that make use of field
theoretical methods to describe the physics of hadrons at finite temperature
and density. I concentrate on two of the main topics that have been explored in
the last few years: (1) The search for the structure of the phase diagram and
(2) analytical signals linked to the chiral symmetry restoration/deconfinement.


title: $SO(N)$ Lattice Gauge Theory, planar and beyond

abstract:
  Lattice Gauge theories have been studied in the physics literature as
discrete approximations to quantum Yang-Mills theory for a long time. Primary
statistics of interest in these models are expectations of the so called
"Wilson loop variables". In this article we continue the program initiated by
Chatterjee (2015) to understand Wilson loop expectations in Lattice Gauge
theories in a certain limit through gauge-string duality. The objective in this
paper is to better understand the underlying combinatorics in the strong
coupling regime, by giving a more geometric picture of string trajectories
involving correspondence to objects such as decorated trees and non-crossing
partitions. Using connections with Free Probability theory, we provide an
elaborate description of loop expectations in the planar setting, which
provides certain insights about structures of higher dimensional trajectories
as well. Exploiting this, we construct an example showing that in any
dimension, the Wilson loop area law lower bound does not hold in full
generality.


title: Anti-de Sitter particles and manifest (super)isometries

abstract:
  Starting from the classical action for a spin-zero particle in a
D-dimensional anti-Sitter (AdS) spacetime, we recover the
Breitenlohner-Freedman bound by quantization. For D=4,5,7, and using an Sl(2;K)
spinor notation for K=R,C,H, we find a bi-twistor form of the action for which
the AdS isometry group is linearly realised, although only for zero mass when
D=4,7, in agreement with previous constructions. For zero mass and D=4, the
conformal isometry group is linearly realized. We extend these results to the
superparticle in the maximally supersymmetric "AdS x S" string/M-theory vacua,
showing that quantization yields a 128+128 component supermultiplet. We also
extend them to the null string.


title: Automated Selection of Uniform Regions for CT Image Quality Detection

abstract:
  CT images are widely used in pathology detection and follow-up treatment
procedures. Accurate identification of pathological features requires
diagnostic quality CT images with minimal noise and artifact variation. In this
work, a novel Fourier-transform based metric for image quality (IQ) estimation
is presented that correlates to additive CT image noise. In the proposed
method, two windowed CT image subset regions are analyzed together to identify
the extent of variation in the corresponding Fourier-domain spectrum. The two
square windows are chosen such that their center pixels coincide and one window
is a subset of the other. The Fourier-domain spectral difference between these
two sub-sampled windows is then used to isolate spatial regions-of-interest
(ROI) with low signal variation (ROI-LV) and high signal variation (ROI-HV),
respectively. Finally, the spatial variance ($var$), standard deviation
($std$), coefficient of variance ($cov$) and the fraction of abdominal ROI
pixels in ROI-LV ($\nu'(q)$), are analyzed with respect to CT image noise. For
the phantom CT images, $var$ and $std$ correlate to CT image noise ($|r|>0.76$
($p\ll0.001$)), though not as well as $\nu'(q)$ ($r=0.96$ ($p\ll0.001$)).
However, for the combined phantom and patient CT images, $var$ and $std$ do not
correlate well with CT image noise ($|r|<0.46$ ($p\ll0.001$)) as compared to
$\nu'(q)$ ($r=0.95$ ($p\ll0.001$)). Thus, the proposed method and the metric,
$\nu'(q)$, can be useful to quantitatively estimate CT image noise.


title:
A signal separation technique for sub-cellular imaging using dynamic
  optical coherence tomography

abstract:
  This paper aims at imaging the dynamics of metabolic activity of cells. Using
dynamic optical coherence tomography, we introduce a new multi-particle
dynamical model to simulate the movements of the collagen and the cell
metabolic activity and develop an efficient signal separation technique for
sub-cellular imaging. We perform a singular-value decomposition of the dynamic
optical images to isolate the intensity of the metabolic activity. We prove
that the largest eigenvalue of the associated Casorati matrix corresponds to
the collagen. We present several numerical simulations to illustrate and
validate our approach.


title:
Collective excitations in liquid DMSO : FIR spectrum, Low frequency
  vibrational density of states and ultrafast dipolar solvation dynamics

abstract:
  Valuable dynamical and structural information about neat liquid DMSO at
ambient conditions can be obtained through study of low frequency vibrations in
the far infrared (FIR), that is, terahertz regime. For DMSO, collective
excitations as well as single molecule stretches and bends have been measured
by different kinds of experiments such as OHD-RIKES and terahertz spectroscopy.
In the present work we investigate the intermolecular vibrational spectrum of
DMSO through three different computational techniques namely (i) the far-infra
red spectrum obtained through Fourier transform of total dipole moment auto
time correlation function, (ii) from Fourier transform of the translational and
angular velocity time autocorrelation functions and a (iii) quenched normal
mode analysis of the parent liquid at 300K. The three spectrum, although
exhibit differences among each other, reveal similar features which are in
good, semi-quantitative, agreement with experimental results. Study of
participation ratio of the density of states obtained from normal mode analysis
shows that the broad spectrum around 100 cm-1 involves collective oscillations
of 300-400 molecules. Dipolar solvation dynamics exhibit ultrafast energy
relaxation (dipolar solvation dynamics) with initial time correlation function
around 140 fs which can be attributed to the coupling to the collective
excitations. We compare properties of DMSO with those of water vis-a-vis the
existence of the low frequency collective modes. Lastly, we find that the
collective excitation spectrum exhibits strong temperature dependence.


title:
A subtle IR excess associated with a young White Dwarf in the
  Edinburgh-Cape Blue Object Survey

abstract:
  We report the discovery of a subtle infrared excess associated with the young
white dwarf EC\,05365--4749 at 3.35 and 4.6\,$\mu$m. Follow-up spectroscopic
observations are consistent with a hydrogen atmosphere white dwarf of effective
temperature 22\,800\,K and log [\emph{g} (\,cm\,s$^{-2}$) ] = 8.19. High
resolution spectroscopy reveals atmospheric metal pollution with logarithmic
abundances of [Mg/H] = --5.36 and [Ca/H] = --5.75, confirming the white dwarf
is actively accreting from a metal-rich source with an intriguing abundance
pattern. We find that the infrared excess is well modeled by a flat, opaque
debris disk, though disk parameters are not well constrained by the small
number of infrared excess points. We further demonstrate that relaxing the
assumption of a circular dusty debris disk to include elliptical disks expands
the widths of acceptable disks, adding an alternative interpretation to the
subtle infrared excesses commonly observed around young white dwarfs.


title: Manifest Duality for Partially Massless Higher Spins

abstract:
  In four dimensions, partially massless fields of all spins and depths possess
a duality invariance akin to electric-magnetic duality. We construct
metric-like gauge invariant curvature tensors for partially massless fields of
all integer spins and depths, and show how the partially massless equations of
motion can be recovered from first order field equations and Bianchi identities
for these curvatures. This formulation displays duality in its manifestly local
and covariant form, in which it acts to interchange the field equations and
Bianchi identities.


title:
The validation of made-to-measure method for reconstruction of phase
  space distribution functions

abstract:
  We investigate how accurately phase space distribution functions (DFs) in
galactic models can be reconstructed by a made-to-measure (M2M) method, which
constructs $N$-particle models of stellar systems from photometric and various
kinematic data. The advantage of the M2M method is that this method can be
applied to various galactic models without assumption of the spatial symmetries
of gravitational potentials adopted in galactic models, and furthermore,
numerical calculations of the orbits of the stars cannot be severely
constrained by the capacities of computer memories. The M2M method has been
applied to various galactic models. However, the degree of accuracy for the
recovery of DFs derived by the M2M method in galactic models has never been
investigated carefully. Therefore, we show the degree of accuracy for the
recovery of the DFs for the anisotropic Plummer model and the axisymmetric
St\"{a}ckel model, which have analytic solutions of the DFs. Furthermore, this
study provides the dependence of the degree of accuracy for the recovery of the
DFs on various parameters and a procedure adopted in this paper. As a result,
we find that the degree of accuracy for the recovery of the DFs derived by the
M2M method for the spherical target model is a few percent, and more than ten
percent for the axisymmetric target model.


title: BCJ relations from a new symmetry of gauge-theory amplitudes

abstract:
  We introduce a new set of symmetries obeyed by tree-level gauge-theory
amplitudes involving at least one gluon. The symmetry acts as a
momentum-dependent shift on the color factors of the amplitude. Using the
radiation vertex expansion, we prove the invariance under this color-factor
shift of the $n$-gluon amplitude, as well as amplitudes involving massless or
massive particles in an arbitrary representation of the gauge group with spin
zero, one-half, or one. The Bern-Carrasco-Johansson relations are a direct
consequence of this symmetry.
  We also introduce the cubic vertex expansion of an amplitude, and use it to
derive a generalized-gauge-invariant constraint on the kinematic numerators of
the amplitude. We show that the amplitudes of the bi-adjoint scalar theory are
invariant under the color-factor symmetry, and use this to derive the null
eigenvectors of the propagator matrix.
  We generalize the color-factor shift to loop level, and prove the invariance
under this shift of one-loop $n$-gluon amplitudes in any theory that admits a
color-kinematic-dual representation of numerators. We show that the one-loop
color-factor symmetry implies known relations among the integrands of one-loop
color-ordered amplitudes.


title:
Mass modeling of galaxy clusters: quantifying hydrostatic bias and
  contribution from non-thermal pressure

abstract:
  Galaxy cluster mass determinations achieved using X-ray and
Sunyaev-Zel'dovich data combined with the assumption of hydrostatic equilibrium
are generally biased. The bias exists for two main reasons: non-thermal
pressure forces are expected to contribute to the overall pressure balance and
deviations from spherical symmetry and hydrostatic equilibrium can be present.
In this paper, we use a sample of zoom-in hydrodynamical simulations of galaxy
clusters to measure the magnitude of hydrostatic bias and the non-thermal
contribution to the total pressure. We propose a new empirical model for
non-thermal pressure based on our simulations that can be applied to
observations. We show that our model can be successfully applied to remove most
of the bias related to neglection of non-thermal pressure, which is usually not
included in hydrostatic cluster mass profile reconstructions. The use of this
model may significantly improve the calibration of cluster scaling relations
that are a key tool for cluster cosmology.


title:
How to get cool in the heat: comparing analytic models of hot, cold, and
  cooling gas in haloes and galaxies with EAGLE

abstract:
  We use the hydrodynamic, cosmological EAGLE simulations to investigate how
hot gas in haloes condenses to form and grow galaxies. We select haloes from
the simulations that are actively cooling and study the temperature,
distribution, and metallicity of their hot, cold, and transitioning `cooling'
gas, placing these in context of semi-analytic models. Our selection criteria
lead us to focus on Milky Way-like haloes. We find the hot-gas density profiles
of the haloes form a progressively stronger core over time, the nature of which
can be captured by a beta profile that has a simple dependence on redshift. In
contrast, the hot gas that will cool over a time-step is broadly consistent
with a singular isothermal sphere. We find that cooling gas carries a few times
the specific angular momentum of the halo and is offset in spin direction from
the rest of the hot gas. The gas loses ~60% of its specific angular momentum
during the cooling process, generally remaining greater than that of the halo,
and it precesses to become aligned with the cold gas already in the disc. We
find tentative evidence that angular-momentum losses are slightly larger when
gas cools onto dispersion-supported galaxies. We show that an exponential
surface density profile for gas arriving on a disc remains a reasonable
approximation, but a cusp containing ~20% of the mass is always present, and
disc scale radii are larger than predicted by a vanilla Fall & Efstathiou
model. These scale radii are still closely correlated with the halo spin
parameter, for which we suggest an updated prescription for galaxy formation
models.


title:
Variable and polarized radio emission from the T6 brown dwarf WISEP
  J112254.73+255021.5

abstract:
  Route & Wolszczan (2016) recently detected five radio bursts from the T6
dwarf WISEP J112254.73+255021.5 and used the timing of these events to propose
that this object rotates with an ultra-short period of ~17.3 minutes. We
conducted follow-up observations with the Very Large Array and Gemini-North but
found no evidence for this periodicity. We do, however, observe variable,
highly circularly polarized radio emission possibly with a period of 116
minutes, although our observation lasted only 162 minutes and so more data are
needed to confirm it. Our proposed periodicity is typical of other radio-active
ultracool dwarfs. The handedness of the circular polarization alternates with
time and there is no evidence for any unpolarized emission component, the first
time such a phenomenology has been observed in radio studies of very low-mass
stars and brown dwarfs. We suggest that the object's magnetic dipole axis may
be highly misaligned relative to its rotation axis.


title: The GALAH survey: The data reduction pipeline

abstract:
  We present the data reduction procedures being used by the GALAH survey,
carried out with the HERMES fibre-fed, multi-object spectrograph on the 3.9~m
Anglo-Australian Telescope. GALAH is a unique survey, targeting 1 million stars
brighter than magnitude V=14 at a resolution of 28,000 with a goal to measure
the abundances of 29 elements. Such a large number of high resolution spectra
necessitates the development of a reduction pipeline optimized for speed,
accuracy, and consistency. We outline the design and structure of the
Iraf-based reduction pipeline that we developed, specifically for GALAH, to
produce fully calibrated spectra aimed for subsequent stellar atmospheric
parameter estimation. The pipeline takes advantage of existing Iraf routines
and other readily available software so as to be simple to maintain, testable
and reliable. A radial velocity and stellar atmospheric parameter estimator
code is also presented, which is used for further data analysis and yields a
useful verification of the reduction quality. We have used this estimator to
quantify the data quality of GALAH for fibre cross-talk level ($\lesssim0.5$%)
and scattered light ($\sim5$ counts in a typical 20 minutes exposure),
resolution across the field, sky spectrum properties, wavelength solution
reliability (better than $1$ $\mathrm{km\ s^{-1}}$ accuracy) and radial
velocity precision.


title: Localization of certain odd-dimensional manifolds with torus actions

abstract:
  Let a torus $T$ act smoothly on a compact smooth manifold $M$. If the
rational equivariant cohomology $H^*_T(M)$ is a free $H^*_T(pt)$-module, then
according to the Chang-Skjelbred Lemma, it can be determined by the
$1$-skeleton consisting of the $T$-fixed points and $1$-dimensional $T$-orbits
of $M$. When $M$ is an even-dimensional, orientable manifold with 2-dimensional
1-skeleton, Goresky, Kottwitz and MacPherson gave a graphic description of the
equivariant cohomology. In this paper, first we revisit the even-dimensional
GKM theory and introduce a notion of GKM covering, then we consider the case
when $M$ is an odd-dimensional, possibly non-orientable manifold with
$3$-dimensional $1$-skeleton, and give a graphic description of its equivariant
cohomology.


title: Hierarchy of Modular Graph Identities

abstract:
  The low energy expansion of Type II superstring amplitudes at genus one is
organized in terms of modular graph functions associated with Feynman graphs of
a conformal scalar field on the torus. In earlier work, surprising identities
between two-loop graphs at all weights, and between higher-loop graphs of
weights four and five were constructed. In the present paper, these results are
generalized in two complementary directions. First, all identities at weight
six and all dihedral identities at weight seven are obtained and proven.
Whenever the Laurent polynomial at the cusp is available, the form of these
identities confirms the pattern by which the vanishing of the Laurent
polynomial governs the full modular identity. Second, the family of modular
graph functions is extended to include all graphs with derivative couplings and
worldsheet fermions. These extended families of modular graph functions are
shown to obey a hierarchy of inhomogeneous Laplace eigenvalue equations. The
eigenvalues for the extended family of dihedral modular graph functions are
calculated analytically for the simplest infinite sub-families and obtained by
Maple for successively more complicated sub-families. The spectrum is shown to
consist solely of eigenvalues $s(s-1)$ for positive integers $s$ bounded by the
weight, with multiplicities which exhibit rich representation-theoretic
patterns.


title:
DC Conductivities from Non-Relativistic Scaling Geometries with Momentum
  Dissipation

abstract:
  We consider a gravitational theory with two Maxwell fields, a dilatonic
scalar and spatially dependent axions. Black brane solutions to this theory are
Lifshitz-like and violate hyperscaling. Working with electrically charged
solutions, we calculate analytically the holographic DC conductivities when
both gauge fields are allowed to fluctuate. We discuss some of the subtleties
associated with relating the horizon to the boundary data, focusing on the role
of Lifshitz asymptotics and the presence of multiple gauge fields. The axionic
scalars lead to momentum dissipation in the dual holographic theory. Finally,
we examine the behavior of the DC conductivities as a function of temperature,
and comment on the cases in which one can obtain a linear resistivity.


title: Non-equilibrium Fractional Hall Response After a Topological Quench

abstract:
  We theoretically study the Hall response of a lattice system following a
quench where the topology of a filled band is suddenly changed. In the limit
where the physics is dominated by a single Dirac cone, we find that the change
in the Hall conductivity is two-thirds of the quantum of conductivity. We
explore this universal behavior in the Haldane model, and discuss cold-atom
experiments for its observation. Beyond linear response, the Hall effect
crosses over from fractional to integer values. We investigate finite-size
effects, and the role of the harmonic confinement.


title: High-dimensional quantum cloning and applications to quantum hacking

abstract:
  Attempts at cloning a quantum system result in the introduction of
imperfections in the state of the copies. This is a consequence of the
no-cloning theorem, which is a fundamental law of quantum physics and the
backbone of security for quantum communications. Although such perfect copies
are prohibited, a quantum state may be copied with maximal accuracy via various
optimal cloning schemes. Optimal quantum cloning, which lies at the border of
the physical limit imposed by the no-signalling theorem and the Heisenberg
uncertainty principle, has been experimentally realized for low dimensional
photonic states. However, an increase in the dimensionality of quantum systems
is greatly beneficial to quantum computation and communication protocols.
Nonetheless, no experimental demonstration of optimal cloning machines has
hitherto been shown for high-dimensional quantum systems. Here, we perform
optimal cloning of high-dimensional photonic states by means of the
symmetrization method. We show the universality of our technique by conducting
cloning of numerous arbitrary input states, and fully characterize our cloning
machine by performing quantum state tomography on \emph{cloned} photons. In
addition, a cloning attack on a Bennett and Brassard (BB84) quantum key
distribution protocol is experimentally demonstrated in order to reveal the
robustness of high-dimensional states in quantum cryptography.


title:
Dynamic Phases, Clustering, and Lane Formation for Driven Disk Systems
  in the Presence of Quenched Disorder

abstract:
  We numerically examine the dynamic phases and pattern formation of
two-dimensional monodisperse repulsive disks driven over random quenched
disorder. We show that there is a series of distinct dynamic regimes as a
function of increasing drive, including a clogged or pile-up phase near
depinning, a homogeneous disordered flow state, and a dynamically phase
separated regime consisting of high density crystalline regions surrounded by a
low density of disordered disks. At the highest drives the disks arrange into
one-dimensional moving lanes. The phase separated regime has parallels with
phase separation observed in active matter systems, and arises in the disk
system due to the combination of nonequilibrium fluctuations and density
dependent mobility. We discuss how this system exhibits pronounced differences
from previous studies of driven particles moving over random substrates where
the particles, such as superconducting vortices or electron crystals, have
longer range repulsive interactions, and where dynamical phase separation and
strong one-dimensional moving chain effects are not observed. The system we
consider could be realized experimentally using sterically interacting colloids
driven over random pinning arrays or quasi-two-dimensional granular matter
flowing over rough landscapes.


title:
Explaining Inverted Temperature Loops in the Quiet Solar Corona with
  Magnetohydrodynamic Wave Mode Conversion

abstract:
  Coronal loops trace out bipolar, arch-like magnetic fields above the Sun's
surface. Recent measurements that combine rotational tomography, extreme
ultraviolet imaging, and potential-field extrapolation have shown the existence
of large loops with inverted temperature profiles; i.e., loops for which the
apex temperature is a local minimum, not a maximum. These "down loops" appear
to exist primarily in equatorial quiet regions near solar minimum. We simulate
both these and the more prevalent large-scale "up loops" by modeling coronal
heating as a time-steady superposition of: (1) dissipation of incompressible
Alfven-wave turbulence, and (2) dissipation of compressive waves formed by mode
conversion from the initial population of Alfven waves. We found that when a
large percentage (> 99%) of the Alfven waves undergo this conversion, heating
is greatly concentrated at the footpoints and stable "down loops" are created.
In some cases we found loops with three maxima that are also gravitationally
stable. Models that agree with the tomographic temperature data exhibit higher
gas pressures for "down loops" than for "up loops," which is consistent with
observations. These models also show a narrow range of Alfven wave amplitudes:
3 to 6 km/s at the coronal base. This is low in comparison to typical observed
amplitudes of 20 to 30 km/s in bright X-ray loops. However, the large-scale
loops we model are believed to comprise a weaker diffuse background that fills
much of the volume of the corona. By constraining the physics of loops that
underlie quiescent streamers, we hope to better understand the formation of the
slow solar wind.


title:
Entropy for the quantized field in the atom-field interaction: Initial
  mixed field

abstract:
  We study the atom-field interaction when the field is in a mixture of
coherent states. We show that in this case it is possible to calculate
analytically the field entropy for times of the order of twice the collapse
time. Such analytical results are done with the help of numerical analysis.


title:
New smoothed particle hydrodynamics (SPH) formulation for modeling heat
  conduction with solidification and melting

abstract:
  When modelling phase change, the latent heat released (absorbed) during
solidification (melting) must be included in the heat transfer equation. In
this paper, different SPH methods for the implementation of latent heat, in the
context of transient heat conduction, are derived and tested. First, SPH
discretizations of two finite element methods are presented, but these prove to
be computationally expensive. Then, by starting from a simple approximation and
enhancing accuracy using different numerical treatments, a new SPH method is
introduced, that is fast and easy to implement. An evaluation of this new
method on various analytical and numerical results confirms its accuracy and
robustness.


title: Self-organised-criticality and punctuated equilibrium in bouncing balls

abstract:
  A nonlinearly coupled system of bouncing balls is shown to exhibit features
like self-organised-criticality (SOC) and punctuated equilibrium (PE) in
suitable parameter domains. The temporal evolution of the non-stationary
amplitudes is analysed through local methods to unravel the transient periodic
components and fluctuations giving rise to SOC and PE type behaviours. This
simple dynamical system follows Gutenberg-Richter relation and also manifests
the Devil's staircase, explicating the universality of these features in
diverse complex systems.


title:
Exactly solvable quantum few-body systems associated with the symmetries
  of the three-dimensional and four-dimensional icosahedra

abstract:
  The purpose of this article is to demonstrate that non-crystallographic
reflection groups can be used to build new solvable quantum particle systems.
We explicitly construct a one-parametric family of solvable four-body systems
on a line, related to the symmetry of a regular icosahedron: in two distinct
limiting cases the system is constrained to a half-line. We repeat the program
for a 600-cell, a four-dimensional generalization of the regular
three-dimensional icosahedron.

categories: math-ph cond-mat.quant-gas math.MP nlin.SI


title: Observable Deviations from Homogeneity in an Inhomogeneous Universe

abstract:
  How does inhomogeneity affect our interpretation of cosmological
observations? It has long been wondered to what extent the observable
properties of an inhomogeneous universe differ from those of a corresponding
Friedman-Lemaitre-Robertson-Walker (FLRW) model, and how the inhomogeneities
affect that correspondence. Here, we use numerical relativity to study the
behavior of light beams traversing an inhomogeneous universe and construct the
resulting Hubble diagrams. The universe that emerges exhibits an average FLRW
behavior, but inhomogeneous structures contribute to deviations in observables
across the observer's sky. We also investigate the relationship between angular
diameter distance and the angular extent of a source, finding deviations that
grow with source redshift. These departures from FLRW are important
path-dependent effects with implications for using real observables in an
inhomogeneous universe such as our own.


title: Revisiting the thermochemistry of chlorine fluorides

abstract:
  In this work, accurate calculations of standard enthalpies of formation of
chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed
through the isodesmic reactions scheme. It is argued that, for many chlorine
fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not
capable to predict enthalpy values nearing chemical accuracy if atomization
scheme is used. This is underpinned by a thorough analysis of total atomization
energy results and the inspection of multireference features of these
compounds. Other thermodynamic quantities were also calculated at different
temperatures. In order to complement the energetic description, elimination
curves were studied through density functional theory as a computationally
affordable alternative to highly correlated wave function-based methods.


title:
Anomalous orbital structure in a spinel-perovskite interface
  $\gamma$-Al$_2$O$_3$/SrTiO$_3$

abstract:
  In all archetypical reported (001)-oriented perovskite heterostructures, it
has been deduced that the preferential occupation of two-dimensional electron
gases is in-plane $d_\textrm{xy}$ state. In sharp contrast to this, the
investigated electronic structure of a spinel-perovskite heterostructure
$\gamma$-Al$_2$O$_3$/SrTiO$_3$ by resonant soft X-ray linear dichroism,
demonstrates that the preferential occupation is out-of-plane
$d_\textrm{xz}$/$d_\textrm{yz}$ states for interfacial electrons. Moreover, the
impact of strain further corroborates that this anomalous orbital structure can
be linked to the altered crystal field at the interface and symmetry breaking
of the interfacial structural units. Our findings provide another interesting
route to engineer emergent quantum states with deterministic orbital symmetry.