title:
Performance of spatial Multi-LRU caching under traffic with temporal
  locality

abstract:
  In this work a novel family of decentralised caching policies for wireless
networks is introduced, referred to as spatial multi-LRU. These improve
cache-hit probability by exploiting multi-coverage. Two variations are
proposed, the multi-LRU-One and -All, which differ in the number of replicas
inserted in the covering edge-caches. The evaluation is done under spatial
traffic that exhibits temporal locality, with varying content catalogue and
dependent demands. The performance metric is hit probability and the policies
are compared to (1) the single-LRU and (2) an upper bound for all centralised
policies with periodic popularity updates. Numerical results show the multi-LRU
policies outperform both comparison policies. The reason is their passive
adaptability to popularity changes. Between the -One and -All variation, which
one is preferable strongly depends on the available storage space and on
traffic characteristics. The performance also depends on the popularity shape.


title: Spherical collapse of dark matter haloes in tidal gravitational fields

abstract:
  We study the spherical collapse model in the presence of external
gravitational tidal shear fields for different dark energy scenarios and
investigate the impact on the mass function and cluster number counts. While
previous studies of the influence of shear and rotation on $\delta_\mathrm{c}$
have been performed with heuristically motivated models, we try to avoid this
model dependence and sample the external tidal shear values directly from the
statistics of the underlying linearly evolved density field based on first
order Lagrangian perturbation theory. Within this self-consistent approach, in
the sense that we restrict our treatment to scales where linear theory is still
applicable, only fluctuations larger than the scale of the considered objects
are included into the sampling process which naturally introduces a mass
dependence of $\delta_\mathrm{c}$. We find that shear effects are predominant
for smaller objects and at lower redshifts, i. e. the effect on
$\delta_\mathrm{c}$ is at or below the percent level for the $\Lambda$CDM
model. For dark energy models we also find small but noticeable differences,
similar to $\Lambda$CDM. The virial overdensity $\Delta_\mathrm{V}$ is nearly
unaffected by the external shear. The now mass dependent $\delta_c$ is used to
evaluate the mass function for different dark energy scenarios and afterwards
to predict cluster number counts, which indicate that ignoring the shear
contribution can lead to biases of the order of $1\sigma$ in the estimation of
cosmological parameters like $\Omega_\mathrm{m}$, $\sigma_8$ or $w$.


title: The maximum size of a partial spread II: Upper bounds

abstract:
  Let $n$ and $t$ be positive integers with $t<n$, and let $q$ be a prime
power. A partial $(t-1)$-spread of ${\rm PG}(n-1,q)$ is a set of
$(t-1)$-dimensional subspaces of ${\rm PG}(n-1,q)$ that are pairwise disjoint.
Let $r\equiv n\pmod{t}$ with $0\leq r<t$, and let ${\theta}_i=(q^i-1)/(q-1)$.
We essentially prove that if $2\leq r<t\leq {\theta}_r$, then the maximum size
of a partial $(t-1)$-spread of ${\rm PG}(n-1,q)$ is bounded from above by
$({\theta}_n-{\theta}_{t+r})/{\theta}_t+q^r-(q-1)(t-3)+1$. We actually give
tighter bounds when certain divisibility conditions are satisfied. These bounds
improve on the previously known upper bound for the maximum size partial
($t-1$)-spreads of ${\rm PG}(n-1,q)$; for instance, when
$\lceil\frac{{\theta}_r}{2}\rceil+4\leq t\leq {\theta}_r$ and $q>2$. The exact
value of the maximum size partial $(t-1)$-spread has been recently determined
for $t>{\theta}_r$ by the authors of this paper (see N\u{a}stase-Sissokho
[21]).


title: Weyl node with random vector potential

abstract:
  We study Weyl semimetals in the presence of generic disorder, consisting of a
random vector potential as well as a random scalar potential. We derive
renormalization group flow equations to second order in the disorder strength.
These flow equations predict a disorder-induced phase transition between a
pseudo-ballistic weak-disorder phase and a diffusive strong-disorder phase for
sufficiently strong random scalar potential or for a pure three-component
random vector potential. We verify these predictions using a numerical study of
the density of states near the Weyl point and of quantum transport properties
at the Weyl point. In contrast, for a pure single-component random vector
potential the diffusive strong-disorder phase is absent.


title:
Renormalization group functions of $\phi^4$ theory in the MS-scheme to
  six loops

abstract:
  Subdivergences constitute a major obstacle to the evaluation of Feynman
integrals and an expression in terms of finite quantities can be a considerable
advantage for both analytic and numeric calculations. We report on our
implementation of the suggestion by F. Brown and D. Kreimer, who proposed to
use a modified BPHZ scheme where all counterterms are single-scale integrals.
Paired with parametric integration via hyperlogarithms, this method is
particularly well suited for the computation of renormalization group functions
and easily automated. As an application of this approach we compute the 6-loop
beta function and anomalous dimensions of the $\phi^4$ model.


title:
Synchronization of electrically coupled stochastic magnetic oscillators
  induced by thermal and electrical noise

abstract:
  Superparamagnetic tunnel junctions are nanostructures that auto-oscillate
stochastically under the effect of thermal noise. Recent works showed that
despite their stochasticity, such junctions possess a capability to synchronize
to subthreshold voltage drives, in a way that can be enhanced or controlled by
adding noise. In this work, we investigate a system composed of two
electrically coupled junctions, connected in series to a periodic voltage
source. We make use of numerical simulations and of an analytical model to
demonstrate that both junctions can be phase-locked to the drive, in phase or
in anti-phase. This synchronization phenomenon can be controlled by both
thermal and electrical noises, although the two types of noises induce
qualitatively different behaviors. Namely, thermal noise can stabilize a regime
where one junction is phase-locked to the drive voltage while the other is
blocked in one state. On the contrary, electrical noise causes the junctions to
have highly correlated behaviors and thus cannot induce the latter. These
results open the way for the design of superparamagnetic tunnel junctions that
can perform computation through synchronization, and which harvest the largest
part of their energy consumption from thermal noise.


title: Unique Measure for Time-Dependent Random Dynamical Systems

abstract:
  This paper proves the uniqueness of measure for the two-dimensional
Navier-Stokes equations under a random kick-force and a time-dependent
deterministic force. By extending a result for uniqueness of measure for
time-homogeneous Markov processes to the time-inhomogeneous case, it is shown
that the measures are exponentially mixing for the 2D Navier-Stokes equations
on the sphere.


title:
Leading two-loop corrections to the Higgs boson masses in SUSY models
  with Dirac gauginos

abstract:
  We compute the two-loop O(as*at) corrections to the Higgs boson masses in
supersymmetric extensions of the Standard Model with Dirac gaugino masses. We
rely on the effective-potential technique, allow for both Dirac and Majorana
mass terms for the gluinos, and compute the corrections in both the DRbar and
on-shell renormalisation schemes. We give detailed results for the MDGSSM and
the MRSSM, and simple approximate formulae valid in the decoupling limit for
all currently-studied variants of supersymmetric models with Dirac gluinos.
These results represent the first explicit two-loop calculation of Higgs boson
masses in supersymmetric models beyond the MSSM and the NMSSM.


title:
HiPERCAM: A high-speed, quintuple-beam CCD camera for the study of rapid
  variability in the Universe

abstract:
  HiPERCAM is a high-speed camera for the study of rapid variability in the
Universe. The project is funded by a 3.5MEuro European Research Council
Advanced Grant. HiPERCAM builds on the success of our previous instrument,
ULTRACAM, with very significant improvements in performance thanks to the use
of the latest technologies. HiPERCAM will use 4 dichroic beamsplitters to image
simultaneously in 5 optical channels covering the u'g'r'i'z' bands. Frame rates
of over 1000 per second will be achievable using an ESO CCD controller (NGC),
with every frame GPS timestamped. The detectors are custom-made, frame-transfer
CCDs from e2v, with 4 low-noise (2.5e-) outputs, mounted in small
thermoelectrically-cooled heads operated at 180 K, resulting in virtually no
dark current. The two reddest CCDs will be deep-depletion devices with
anti-etaloning, providing high quantum efficiencies across the red part of the
spectrum with no fringing. The instrument will also incorporate scintillation
noise correction via the conjugate-plane photometry technique. The
opto-mechanical chassis will make use of additive manufacturing techniques in
metal to make a light-weight, rigid and temperature-invariant structure. First
light is expected on the 4.2m William Herschel Telescope on La Palma in 2017
(on which the field of view will be 10' with a 0.3"/pixel scale), with
subsequent use planned on the 10.4m Gran Telescopio Canarias on La Palma (on
which the field of view will be 4' with a 0.11"/pixel scale) and the 3.5m New
Technology Telescope in Chile.


title:
Observation and analysis of the new W-type W UMa eclipsing binary VSX
  J053024.8+842243

abstract:
  Using multicolour photometry we have confirmed the binary nature of the new
W-type W UMa eclipsing binary VSX J053024.8+842243 and established its primary
eclipse ephemeris to be HJD = 2455924.38150(26) + 0.4322929(1) * E. Using the
light curve modelling code PHOEBE and published data on the evolution of W-type
contact binaries we found the primary and secondary components to have masses
0.50 Msun and 1.44 Msun, radii 0.87 Rsun and 1.42 Rsun, luminosities 0.98 Lsun
and 1.91 Lsun, temperatures 6145 K and 5702 K and binary orbit inclination
59.4{\deg}. We found the distance to the binary to be 511 parsec, its E(B-V)
colour excess 0.04 and its intrinsic (B-V) colour index 0.62. A low resolution
spectrum corrected for interstellar reddening confirmed its spectral type as
G2V.


title:
True Error Control for the Localized Reduced Basis Method for Parabolic
  Problems

abstract:
  We present an abstract framework for a posteriori error estimation for
approximations of scalar parabolic evolution equations, based on elliptic
reconstruction techniques [10, 9, 3, 5]. In addition to its original
application (to derive error estimates on the discretization error), we extend
the scope of this framework to derive offline/online decomposable a posteriori
estimates on the model reduction error in the context of Reduced Basis (RB)
methods. In addition, we present offline/online decomposable a posteriori error
estimates on the full approximation error (including discretization as well as
model reduction error) in the context of the localized RB method [14]. Hence,
this work generalizes the localized RB method with true error certification to
parabolic problems. Numerical experiments are given to demonstrate the
applicability of the approach.


title:
Orbital angular momentum of scalar field generated by gravitational
  scatterings

abstract:
  It has been expected that astronomical observations to detect the orbital
angular momenta of electromagnetic waves may give us a new insight into
astrophysics. Previous works pointed out the possibility that a rotating black
hole can produce orbital angular momenta of electromagnetic waves through
gravitational scattering, and the spin parameter of the black hole can be
measured by observing them. However, the mechanism how the orbital angular
momentum of the electromagnetic wave is generated by the gravitational
scattering has not been clarified sufficiently. In this paper, in order to
understand it from a point of view of gravitational lensing effects, we
consider an emitter which radiates a spherical wave of the real massless scalar
field and study the deformation of the scalar wave by the gravitational
scattering due to a black hole by invoking the geometrical optics
approximation. We show that the frame dragging caused by the rotating black
hole is not a necessary condition for generating the orbital angular momentum
of the scalar wave. However, its components parallel to the direction cosines
of images appear only if the black hole is rotating.


title:
Range-separated tensor formats for numerical modeling of many-particle
  interaction potentials

abstract:
  We introduce and analyze the new range-separated (RS) canonical/Tucker tensor
format which aims for numerical modeling of the 3D long-range interaction
potentials in multi-particle systems. The main idea of the RS tensor format is
the independent grid-based low-rank representation of the localized and global
parts in the target tensor which allows the efficient numerical approximation
of $N$-particle interaction potentials. The single-particle reference potential
like $1/\|x\|$ is split into a sum of localized and long-range low-rank
canonical tensors represented on a fine 3D $n\times n\times n$ Cartesian grid.
The smoothed long-range contribution to the total potential sum is represented
on the 3D grid in $O(n)$ storage via the low-rank canonical/Tucker tensor. We
prove that the Tucker rank parameters depend only logarithmically on the number
of particles $N$ and the grid-size $n$. Agglomeration of the short range part
in the sum is reduced to an independent treatment of $N$ localized terms with
almost disjoint effective supports, calculated in $O(N)$ operations. Thus, the
cumulated sum of short range clusters is parametrized by a single low-rank
canonical reference tensor with a local support, accomplished by a list of
particle coordinates and their charges. The RS canonical/Tucker tensor
representations reduce the cost of multi-linear algebraic operations on the 3D
potential sums arising in modeling of multi-dimensional data by radial basis
functions, say, in computation of the electrostatic potential of a protein, in
3D integration and convolution transforms, computation of gradients, forces and
the interaction energy of a many-particle systems, and in low parametric
fitting of multi-dimensional scattered data by reducing all of them to 1D
calculations.


title: Simulation Results on Selector Adaptation in Behavior Trees

abstract:
  Behavior trees (BTs) emerged from video game development as a graphical
language for modeling intelligent agent behavior. However as initially
implemented, behavior trees are static plans. This paper adds to recent
literature exploring the ability of BTs to adapt to their success or failure in
achieving tasks. The "Selector" node of a BT tries alternative strategies (its
children) and returns success only if all of its children return failure. This
paper studies several means by which Selector nodes can learn from experience,
in particular, learn conditional probabilities of success based on sensor
information, and modify the execution order based on the learned iformation.
Furthermore, a "Greedy Selector" is studied which only tries the child having
the highest success probability. Simulation results indicate significantly
increased task performance, especially when frequentist probability estimate is
conditioned on sensor information. The Greedy selector was ineffective unless
it was preceded by a period of training in which all children were exercised.


title: Scalar Gravitational Waves in the Effective Theory of Gravity

abstract:
  As a low energy effective field theory, classical General Relativity receives
an infrared relevant modification from the conformal trace anomaly of the
energy-momentum tensor of massless, or nearly massless, quantum fields. The
local form of the effective action associated with the trace anomaly is
expressed in terms of a dynamical scalar field that couples to the conformal
factor of the spacetime metric, allowing it to propagate over macroscopic
distances. Linearized around flat spacetime, this semi-classical EFT admits
scalar gravitational wave solutions in addition to the transversely polarized
tensor waves of the classical Einstein theory. The amplitude of the scalar wave
modes, as well as their energy and energy flux which are positive and contain a
monopole moment, are computed. Astrophysical sources for scalar gravitational
waves are considered, with the excited gluonic condensates in the interiors of
neutron stars in merger events with other compact objects likely to provide the
strongest burst signals.


title: The new challenges of multiplex networks: measures and models

abstract:
  What do societies, the Internet, and the human brain have in common? They are
all examples of complex relational systems, whose emerging behaviours are
largely determined by the non-trivial networks of interactions among their
constituents, namely individuals, computers, or neurons, rather than the
properties of the units themselves. In the last two decades, network scientists
have proposed models of increasing complexity to better understand real-world
systems. Only recently we have realised that multiplexity, i.e. the coexistence
of several types of interactions among the constituents of a complex system, is
responsible for substantial qualitative and quantitative differences in the
type and variety of behaviours that a complex system can exhibit. As a
consequence, multilayer and multiplex networks have become a hot topic in
complexity science. Here we provide an overview of some of the measures
proposed so far to characterise the structure of multiplex networks, and a
selection of models aiming at reproducing those structural properties and
quantifying their statistical significance. Focusing on a subset of relevant
topics, this brief review is a quite comprehensive introduction to the most
basic tools for the analysis of multiplex networks observed in the real-world.
The wide applicability of multiplex networks as a framework to model complex
systems in different fields, from biology to social sciences, and the
colloquial tone of the paper will make it an interesting read for researchers
working on both theoretical and experimental analysis of networked systems.

categories: physics.soc-ph cond-mat.dis-nn cond-mat.stat-mech cs.SI


title:
Penambahan emosi menggunakan metode manipulasi prosodi untuk sistem text
  to speech bahasa Indonesia

abstract:
  Adding an emotions using prosody manipulation method for Indonesian text to
speech system. Text To Speech (TTS) is a system that can convert text in one
language into speech, accordance with the reading of the text in the language
used. The focus of this research is a natural sounding concept, the make
"humanize" for the pronunciation of voice synthesis system Text To Speech.
Humans have emotions / intonation that may affect the sound produced. The main
requirement for the system used Text To Speech in this research is eSpeak, the
database MBROLA using id1, Human Speech Corpus database from a website that
summarizes the words with the highest frequency (Most Common Words) used in a
country. And there are 3 types of emotional / intonation designed base. There
is a happy, angry and sad emotion. Method for develop the emotional filter is
manipulate the relevant features of prosody (especially pitch and duration
value) using a predetermined rate factor that has been established by analyzing
the differences between the standard output Text To Speech and voice recording
with emotional prosody / a particular intonation. The test results for the
perception tests of Human Speech Corpus for happy emotion is 95 %, 96.25 % for
angry emotion and 98.75 % for sad emotions. For perception test system carried
by intelligibility and naturalness test. Intelligibility test for the accuracy
of sound with the original sentence is 93.3%, and for clarity rate for each
sentence is 62.8%. For naturalness, accuracy emotional election amounted to
75.6 % for happy emotion, 73.3 % for angry emotion, and 60 % for sad emotions.
  -----
  Text To Speech (TTS) merupakan suatu sistem yang dapat mengonversi teks dalam
format suatu bahasa menjadi ucapan sesuai dengan pembacaan teks dalam bahasa
yang digunakan.


title:
The magnetic precursor of the pressure-induced superconductivity in
  Fe-ladder compound

abstract:
  The pressure effects on the antiferromagentic orders in iron-based ladder
compounds CsFe$_2$Se$_3$ and BaFe$_2$S$_3$ have been studied using neutron
diffraction. With identical crystal structure and similar magnetic structures,
the two compounds exhibit highly contrasting magnetic behaviors under moderate
external pressures. In CsFe$_2$Se$_3$ the ladders are brought much closer to
each other by pressure, but the stripe-type magnetic order shows no observable
change. In contrast, the stripe order in BaFe$_2$S$_3$, undergoes a quantum
phase transition where an abrupt increase of N$\acute{e}$el temperature by more
than 50$\%$ occurs at about 1 GPa, accompanied by a jump in the ordered moment.
With its spin structure unchanged, BaFe$_2$S$_3$ enters an enhanced magnetic
phase that bears the characteristics of an orbital selective Mott phase, which
is the true neighbor of superconductivity emerging at higher pressures.


title: The habitability of the Universe through 13 billion years of cosmic time

abstract:
  The field of astrobiology has made tremendous progress in modelling
galactic-scale habitable zones which offer a stable environment for life to
form and evolve in complexity. Recently, this idea has been extended to
cosmological scales by studies modelling the habitability of the local Universe
in its entirety (e.g. Dayal et al. 2015; Li & Zhang 2015). However, all of
these studies have solely focused on estimating the potentially detrimental
effects of either Type II supernovae (SNII) or Gamma Ray Bursts (GRBs),
ignoring the contributions from Type Ia supernovae (SNIa) and active galactic
nuclei (AGN). In this study we follow two different approaches, based on (i)
the amplitude of deleterious radiation and (ii) the total planet-hosting volume
irradiated by deleterious radiation. We simultaneously track the contributions
from the key astrophysical sources (SNII, SNIa, AGN and GRBs) for the entire
Universe, for both scenarios, to determine its habitability through 13.8
billion years of cosmic time. We find that SNII dominate the total radiation
budget and the volume irradiated by deleterious radiation at any cosmic epoch
closely followed by SNIa (that contribute half as much as SNII), with GRBs and
AGN making up a negligible portion (<1%). Secondly, as a result of the total
mass in stars (or the total number of planets) slowly building-up with time and
the total deleterious radiation density, and volume affected, falling-off after
the first 3 billion years, we find that the Universe has steadily increased in
habitability through cosmic time. We find that, depending on the exact model
assumptions, the Universe is 2.5 to 20 times more habitable today compared to
when life first appeared on the Earth 4 billion years ago. We find that this
increase in habitability will persist until the final stars die out over the
next hundreds of billions of years.


title:
Quintuple: a Python 5-qubit quantum computer simulator to facilitate
  cloud quantum computing

abstract:
  In May 2016 IBM released access to its 5-qubit quantum computer to the
scientific community, its "IBM Quantum Experience" since acquiring over 25,000
users from students, educators and researchers around the globe. In the short
time since the "IBM Quantum Experience" became available, a flurry of research
results on 5-qubit systems have been published derived from the platform
hardware. Quintuple is an open-source object-oriented Python module
implementing the simulation of the "IBM Quantum Experience" hardware. Quintuple
quantum algorithms can be programmed and run via a custom language fully
compatible with the "IBM Quantum Experience" or in pure Python. Over 40 example
programs are provided with expected results, including Grover's Algorithm and
the Deutsch-Jozsa algorithm. Quintuple contributes to the study of 5-qubit
systems and the development and debugging of quantum algorithms for deployment
on the "IBM Quantum Experience" hardware.


title:
All-strain based valley filter in graphene nanoribbons using snake
  states

abstract:
  A pseudo-magnetic field kink can be realized along a graphene nanoribbon
using strain engineering. Electron transport along this kink is governed by
snake states that are characterized by a single propagation direction. Those
pseudo-magnetic fields point towards opposite directions in the K and K'
valleys, leading to valley polarized snake states. In a graphene nanoribbon
with armchair edges this effect results in a valley filter that is based only
on strain engineering. We discuss how to maximize this valley filtering by
adjusting the parameters that define the stress distribution along the graphene
ribbon.


title: Density scaling relation in Orion A: effects of region selection

abstract:
  Recently Stanchev et al. (2015) proposed a technique to derive density
scaling relations in a star-forming region from analysis of the probability
distribution function of column density. We address the possible dependence of
the outcome on the selection of probe zones, applying the method to Planck
dust-opacity data on Orion A. The derived steep scaling relation of mean
density with index -1.6 in the molecular cloud (so called `Central filament')
points to its self-gravitating nature. The result is reproduced also for large
parts of the clouds' vicinity which indicates major role of gravity in the
energy balance of the entire star-forming region.


title: How flat is flat in random interface growth?

abstract:
  Domains of attraction are identified for the universality classes of
one-point asymptotic fluctuations for the Kardar-Parisi-Zhang (KPZ) equation
with general initial data. The criterion is based on a large deviation rate
function for the rescaled initial data, which arises naturally from the
Hopf-Cole transformation. This allows us, in particular, to distinguish the
domains of attraction of curved, flat, and Brownian initial data, and to
identify the boundary between the curved and flat domains of attraction, which
turns out to correspond to square root initial data.
  The distribution of the asymptotic one-point fluctuations is characterized by
means of a variational formula written in terms of certain limiting processes
(arising as subsequential limits of the spatial fluctuations of KPZ equation
with narrow wedge initial data, as shown in [CH16]) which are widely believed
to coincide with the Airy$_2$ process. In order to identify these distributions
for general initial data, we extend earlier results on continuum statistics of
the Airy$_2$ process to probabilities involving the process on the entire line.
In particular, this allows us to write an explicit Fredholm determinant formula
for the case of square root initial data.


title: Shock waves in dispersive hydrodynamics with non-convex dispersion

abstract:
  Dissipationless hydrodynamics regularized by dispersion describe a number of
physical media including water waves, nonlinear optics, and Bose-Einstein
condensates. As in the classical theory of hyperbolic equations where a
non-convex flux leads to non-classical solution structures, a non-convex linear
dispersion relation provides an intriguing dispersive hydrodynamic analogue.
Here, the fifth order Korteweg-de Vries (KdV) equation, also known as the
Kawahara equation, a classical model for shallow water waves, is shown to be a
universal model of Eulerian hydrodynamics with higher order dispersive effects.
Utilizing asymptotic methods and numerical computations, this work classifies
the long-time behavior of solutions for step-like initial data. For convex
dispersion, the result is a dispersive shock wave (DSW), qualitatively and
quantitatively bearing close resemblance to the KdV DSW. For non-convex
dispersion, three distinct dynamic regimes are observed. For small jumps, a
perturbed KdV DSW with positive polarity and orientation is generated,
accompanied by small amplitude radiation from an embedded solitary wave leading
edge, termed a radiating DSW or RDSW. For moderate jumps, a crossover regime is
observed with waves propagating forward and backward from the sharp transition
region. For jumps exceeding a critical threshold, a new type of DSW is observed
we term a translating DSW or TDSW. The TDSW consists of a traveling wave that
connects a partial, non-monotonic, negative solitary wave at the trailing edge
to an interior nonlinear periodic wave. Its speed, a generalized
Rankine-Hugoniot jump condition, is determined by the far-field structure of
the traveling wave. The TDSW is resolved at the leading edge by a harmonic
wavepacket moving with the linear group velocity. The non-classical TDSW
exhibits features common to both dissipative and dispersive shock waves.


title:
Feedback stabilization of the Cahn-Hilliard type system for phase
  separation

abstract:
  This article is concerned with the internal feedback stabilization of the
phase field system of Cahn-Hilliard type, modeling the phase separation in a
binary mixture. Under suitable assumptions on an arbitrarily fixed stationary
solution, we construct via spectral separation arguments a feedback controller
having the support in an arbitrary open subset of the space domain, such that
the closed loop nonlinear system exponentially reach the prescribed stationary
solution. This feedback controller has a finite dimensional structure in the
state space of solutions. In particular, every constant stationary solution is
admissible.


title:
Aharonov-Bohm effect for a fermion field in a planar black hole
  "spacetime"

abstract:
  In this paper we consider the dynamics of a massive spinor field in the
background of the acoustic black hole spacetime. Although this effective metric
is acoustic and describes the propagation of sound waves, it can be considered
as a toy model for the gravitational black hole. In this manner, we study the
properties of the dynamics of the fermion field in this "gravitational"
rotating black hole as well as the vortex background. We compute the
differential cross section through the use of the partial wave approach and
show that an effect similar to the gravitational Aharonov-Bohm effect occurs
for the massive fermion field moving in this effective metric. We discuss the
limiting cases and compare the results with the massless scalar field case.


title: Neutron Star Mass-Radius Constraints using Evolutionary Optimization

abstract:
  The equation of state of cold supra-nuclear-density matter, such as in
neutron stars, is an open question in astrophysics. A promising method for
constraining the neutron star equation of state is modelling pulse profiles of
thermonuclear X-ray burst oscillations from hotspots on accreting neutron
stars. The pulse profiles, constructed using spherical and oblate neutron star
models, are comparable to what would be observed by a next-generation X-ray
timing instrument like ASTROSAT, NICER, or LOFT. In this paper, we showcase the
use of an evolutionary optimization algorithm to fit pulse profiles to
determine the best-fit masses and radii. By fitting synthetic data, we assess
how well the optimization algorithm can recover the input parameters. Multiple
Poisson realizations of the synthetic pulse profiles, constructed with 1.6
million counts and no background, were fitted with the Ferret algorithm to
analyze both statistical and degeneracy-related uncertainty, and to explore how
the goodness-of-fit depends on the input parameters. For the regions of
parameter space sampled by our tests, the best-determined parameter is the
projected velocity of the spot along the observer's line-of-sight, with an
accuracy of $\le3$% compared to the true value and with $\le5$\% statistical
uncertainty. The next best-determined are the mass and radius; for a neutron
star with a spin frequency of 600\,Hz, the best-fit mass and radius are
accurate to $\le5$%, with respective uncertainties of $\le7$% and $\le10$%. The
accuracy and precision depend on the observer inclination and spot co-latitude,
with values of $\sim1$ % achievable in mass and radius if both the inclination
and co-latitude are > 60 degrees.


title:
Unequal Error Protection Querying Policies for the Noisy 20 Questions
  Problem

abstract:
  In this paper, we propose an open-loop unequal-error-protection querying
policy based on superposition coding for the noisy 20 questions problem. In
this problem, a player wishes to successively refine an estimate of the value
of a continuous random variable by posing binary queries and receiving noisy
responses. When the queries are designed non-adaptively as a single block and
the noisy responses are modeled as the output of a binary symmetric channel the
20 questions problem can be mapped to an equivalent problem of channel coding
with unequal error protection (UEP). A new non-adaptive querying strategy based
on UEP superposition coding is introduced whose estimation error decreases with
an exponential rate of convergence that is significantly better than that of
the UEP repetition coding introduced by Variani et al. (2015). With the
proposed querying strategy, the rate of exponential decrease in the number of
queries matches the rate of a closed-loop adaptive scheme where queries are
sequentially designed with the benefit of feedback. Furthermore, the achievable
error exponent is significantly better than that of random block codes
employing equal error protection.


title: Intermodulation in Nonlinear SQUID Metamaterials: Experiment and Theory

abstract:
  The response of nonlinear metamaterials and superconducting electronics to
two-tone excitation is critical for understanding their use as low-noise
amplifiers and tunable filters. A new setting for such studies is that of
metamaterials made of radio frequency superconducting quantum interference
devices (rf-SQUIDs). The two-tone response of self-resonant rf-SQUID meta-atoms
and metamaterials is studied here via intermodulation (IM) measurement over a
broad range of tone frequencies and tone powers. A sharp onset followed by a
surprising strongly suppressed IM region near the resonance is observed. Using
a two time scale analysis technique, we present an analytical theory that
successfully explains our experimental observations. The theory predicts that
the IM can be manipulated with tone power, center frequency, frequency
difference between the two tones, and temperature. This quantitative
understanding potentially allows for the design of rf-SQUID metamaterials with
either very low or very high IM response.


title:
Graphone (one-side hydrogenated graphene) formation on different
  substrates

abstract:
  In this work we present a fully atomistic reactive (ReaxFF force field)
molecular dynamics study of the structural and dynamical aspects of the
one-side hydrogenation of graphene membranes, leading to the formation of the
so-called graphone structure. We have considered different substrates:
graphene, few-layers graphene, graphite and platinum at different temperatures.
Our results showed that the hydrogenation rates are very dependent on the
substrate and thermal effects. Our results also showed that, similarly to
graphane, large hydrogenated domains are unlikely to be formed. These
hydrogenation processes occur through the formation of uncorrelated cluster
domains.


title: The Future of Computing Research: Industry-Academic Collaborations

abstract:
  IT-driven innovation is an enormous factor in the worldwide economic
leadership of the United States. It is larger than finance, construction, or
transportation, and it employs nearly 6% of the US workforce. The top three
companies, as measured by market capitalization, are IT companies - Apple,
Google (now Alphabet), and Microsoft. Facebook, a relatively recent entry in
the top 10 list by market capitalization has surpassed Walmart, the nation's
largest retailer, and the largest employer in the world. The net income of just
the top three exceeds $80 billion - roughly 100 times the total budget of the
NSF CISE directorate which funds 87% of computing research. In short, the
direct return on federal research investments in IT research has been
enormously profitable to the nation.
  The IT industry ecosystem is also evolving. The time from conception to
market of successful products has been cut from years to months. Product life
cycles are increasingly a year or less. This change has pressured companies to
focus industrial R&D on a pipeline or portfolio of technologies that bring
immediate, or almost immediate, value to the companies. To defeat the
competition and stay ahead of the pack, a company must devote resources to
realizing gains that are shorter term, and must remain agile to respond quickly
to market changes driven by new technologies, new startups, evolving user
experience expectations, and the continuous consumer demand for new and
exciting products.
  Amidst this landscape, the Computing Community Consortium convened a
round-table of industry and academic participants to better understand the
landscape of industry-academic interaction, and to discuss possible actions
that might be taken to enhance those interactions. We close with some
recommendations for actions that could expand the lively conversation we
experienced at the round-table to a national scale.


title: Kaehler structures on spin 6-manifolds

abstract:
  We show that many spin 6-manifolds have the homotopy type but not the
homeomorphism type of a Kaehler manifold. Moreover, for given Betti numbers,
there are only finitely many deformation types and hence topological types of
smooth complex projectve spin threefolds of general type. Finally, on a fixed
spin 6-manifold, the Chern numbers take on only finitely many values on all
possible Kaehler structures.


title:
A Chebotarev variant of the Brun-Titchmarsh theorem and bounds for the
  Lang-Trotter conjectures

abstract:
  We improve the Chebotarev variant of the Brun-Titchmarsh theorem proven by
Lagarias, Montgomery, and Odlyzko using the log-free zero density estimate and
zero repulsion phenomenon for Hecke L-functions that were recently proved by
the authors. Our result produces an improvement for the best unconditional
bounds toward two conjectures of Lang and Trotter regarding the distribution of
traces of Frobenius for elliptic curves and holomorphic cuspidal modular forms.
We also obtain new results on the distribution of primes represented by
positive-definite integral binary quadratic forms.


title: Learning Concept Taxonomies from Multi-modal Data

abstract:
  We study the problem of automatically building hypernym taxonomies from
textual and visual data. Previous works in taxonomy induction generally ignore
the increasingly prominent visual data, which encode important perceptual
semantics. Instead, we propose a probabilistic model for taxonomy induction by
jointly leveraging text and images. To avoid hand-crafted feature engineering,
we design end-to-end features based on distributed representations of images
and words. The model is discriminatively trained given a small set of existing
ontologies and is capable of building full taxonomies from scratch for a
collection of unseen conceptual label items with associated images. We evaluate
our model and features on the WordNet hierarchies, where our system outperforms
previous approaches by a large gap.


title:
Abelian $n$-division fields of elliptic curves and Brauer groups of
  product Kummer & abelian surfaces

abstract:
  Let $Y$ be a principal homogeneous space of an abelian surface, or a K3
surface, over a finitely generated extension of $\mathbb{Q}$. In 2008,
Skorobogatov and Zarhin showed that the Brauer group modulo algebraic classes
$\text{Br}\, Y/ \text{Br}_1\, Y$ is finite. We study this quotient for the
family of surfaces that are geometrically isomorphic to a product of isogenous
non-CM elliptic curves, as well as the related family of geometrically Kummer
surfaces; both families can be characterized by their geometric N\'eron-Severi
lattices. Over a field of characteristic $0$, we prove that the existence of a
strong uniform bound on the size of the odd-torsion of $\text{Br}\, Y /
\text{Br}_1\, Y$ is equivalent to the existence of a strong uniform bound on
integers $n$ for which there exist non-CM elliptic curves with abelian
$n$-division fields. Using the same methods we show that, for a fixed prime
$p$, a number field $k$ of fixed degree $r$, and a fixed discriminant of the
geometric N\'eron-Severi lattice, $(\text{Br}\, Y / \text{Br}_1\, Y)[p^\infty]$
is bounded by a constant that depends only on $p$, $r$, and the discriminant.


title:
Quantum superpositions of "common-cause" and "direct-cause" causal
  structures

abstract:
  The constraints arising for a general set of causal relations, both
classically and quantumly, are still poorly understood. As a step in exploring
this question, we consider a coherently controlled superposition of
"direct-cause" and "common-cause" relationships between two events. We propose
an implementation involving the spatial superposition of a mass and general
relativistic time dilation. Finally, we develop a computationally efficient
method to distinguish such genuinely quantum causal structures from classical
(incoherent) mixtures of causal structures and show how to design experimental
verifications of the nonclassicality of a causal structure.


title: Swift: Compiled Inference for Probabilistic Programming Languages

abstract:
  A probabilistic program defines a probability measure over its semantic
structures. One common goal of probabilistic programming languages (PPLs) is to
compute posterior probabilities for arbitrary models and queries, given
observed evidence, using a generic inference engine. Most PPL inference
engines---even the compiled ones---incur significant runtime interpretation
overhead, especially for contingent and open-universe models. This paper
describes Swift, a compiler for the BLOG PPL. Swift-generated code incorporates
optimizations that eliminate interpretation overhead, maintain dynamic
dependencies efficiently, and handle memory management for possible worlds of
varying sizes. Experiments comparing Swift with other PPL engines on a variety
of inference problems demonstrate speedups ranging from 12x to 326x.


title:
Supernova neutrino physics with xenon dark matter detectors: A timely
  perspective

abstract:
  Dark matter detectors that utilize liquid xenon have now achieved tonne-scale
targets, giving them sensitivity to all flavours of supernova neutrinos via
coherent elastic neutrino-nucleus scattering. Considering for the first time a
realistic detector model, we simulate the expected supernova neutrino signal
for different progenitor masses and nuclear equations of state in existing and
upcoming dual-phase liquid xenon experiments. We show that the proportional
scintillation signal (S2) of a dual-phase detector allows for a clear
observation of the neutrino signal and guarantees a particularly low energy
threshold, while the backgrounds are rendered negligible during the supernova
burst. XENON1T (XENONnT and LZ; DARWIN) experiments will be sensitive to a
supernova burst up to 25 (35; 65) kpc from Earth at a significance of more than
5 sigma, observing approximately 35 (123; 704) events from a 27 Msun supernova
progenitor at 10 kpc. Moreover, it will be possible to measure the average
neutrino energy of all flavours, to constrain the total explosion energy, and
to reconstruct the supernova neutrino light curve. Our results suggest that a
large xenon detector such as DARWIN will be competitive with dedicated neutrino
telescopes, while providing complementary information that is not otherwise
accessible.


title:
A Conic Section Problem Involving the Maximum Generalized Golden Right
  Triangle

abstract:
  An interesting conic section problem involving the maximum generalized golden
right triangle $T_2$ is solved, and two simple constructions of $T_2$ are
shown.


title: String Theory Origin of Constrained Multiplets

abstract:
  We study the non-linearly realized spontaneously broken supersymmetry of the
(anti-)D3-brane action in type IIB string theory. The worldvolume fields are
one vector $A_\mu$, three complex scalars $\phi^i$ and four 4d fermions
$\lambda^0$, $\lambda^i$. These transform, in addition to the more familiar N=4
linear supersymmetry, also under 16 spontaneously broken, non-linearly realized
supersymmetries. We argue that the worldvolume fields can be packaged into the
following constrained 4d non-linear N=1 multiplets: four chiral multiplets $S$,
$Y^i$ that satisfy $S^2=SY^i=0$ and contain the worldvolume fermions
$\lambda^0$ and $\lambda^i$; and four chiral multiplets $W_\alpha$, $H^i$ that
satisfy $S W_\alpha=0$ and $S \bar D_{\dot \alpha} \bar H^{\bar \imath}=0$ and
contain the vector $A_\mu$ and the scalars $\phi^i$. We also discuss how
placing an anti-D3-brane on top of intersecting O7-planes can lead to an
orthogonal multiplet $\Phi$ that satisfies $S(\Phi-\bar \Phi)=0$, which is
particularly interesting for inflationary cosmology.


title:
No Timing Variations Observed in Third Transit of Snow-Line Exoplanet
  Kepler-421b

abstract:
  We observed Kepler-421 during the anticipated third transit of the snow-line
exoplanet Kepler-421b in order to constrain the existence and extent of transit
timing variations (TTVs). Previously, the Kepler Spacecraft only observed two
transits of Kepler-421b leaving the planet's transit ephemeris unconstrained.
Our visible light, time-series observations from the 4.3-meter Discovery
Channel Telescope were designed to capture pre-transit baseline and the partial
transit of Kepler-421b barring significant TTVs. We use the light curves to
assess the probabilities of various transit models using both the posterior
odds ratio and the Bayesian Information Criterion (BIC) and find that a transit
model with no TTVs is favored to 3.6-sigma confidence. These observations
suggest that Kepler-421b is either alone in its system or is only experiencing
minor dynamic interactions with an unseen companion. With the Kepler-421b
ephemeris constrained, we calculate future transit times and discuss the
opportunity to characterize the atmosphere of this cold, long-period exoplanet
via transmission spectroscopy. Our investigation emphasizes the difficulties
associated with observing long-period exoplanet transits and the consequences
that arise from failing to refine transit ephemerides.


title:
The properties of hypervelocity stars and S-stars originating from an
  eccentric disc around a supermassive black hole

abstract:
  Hypervelocity stars (HVSs) that are observed in the Galactic halo, are
believed to be accelerated to large velocities by a process of tidal disruption
of binary stars passing close to a supermassive black hole (SMBH) which resides
in the center of the Galaxy. It is, however, still unclear, where these
relatively young stars were born and which dynamical process pushed them to
nearly radial orbits around the SMBH. In this paper we investigate the
possibility that the young binaries originated from a thin eccentric disc,
similar to the one observed in the Galactic center nowadays. By means of direct
N-body simulations, we follow the dynamical evolution of an initially thin and
eccentric disc of stars with a 100% binary fraction orbiting around the SMBH.
Such a configuration leads to Kozai-Lidov oscillations of orbital elements,
bringing considerable amount of binaries to close vicinity of the black hole.
Subsequent tidal disruption of these binaries accelerates one of their
component to velocities well above the escape velocity from the SMBH while the
second component becomes tightly bound to the SMBH. We describe the main
kinematic properties of the escaping and tightly bound stars within our model
and compare them qualitatively to the properties of the observed HVSs and
S-stars, respectively. The most prominent feature is a strong anisotropy in the
directions of the escaping stars which is observed for the Galactic HVSs but
not explained yet.


title:
SMPDF Web: a web-based application for specialized minimal parton
  distribution functions

abstract:
  We present SMPDF Web, a web interface for the construction of parton
distribution functions (PDFs) with a minimal number of error sets needed to
represent the PDF uncertainty of specific processes (SMPDF).


title: Damped Topological Magnons in the Kagom\'{e}-Lattice Ferromagnets

abstract:
  We demonstrate that interactions can substantially undermine the
free-particle description of magnons in ferromagnets on geometrically
frustrated lattices. The anharmonic coupling, facilitated by the
Dzyaloshinskii-Moriya interaction, and a highly-degenerate two-magnon continuum
yield a strong, non-perturbative damping of the high-energy magnon modes. We
provide a detailed account of the effect for the $S=1/2$ ferromagnet on the
kagom\'e lattice and propose further experiments.


title:
The Gamma-Ray Pulsar Population of Globular Clusters: Implications for
  the GeV Excess

abstract:
  It has been suggested that the GeV excess, observed from the region
surrounding the Galactic Center, might originate from a population of
millisecond pulsars that formed in globular clusters. With this in mind, we
employ the publicly available Fermi data to study the gamma-ray emission from
157 globular clusters, identifying a statistically significant signal from 25
of these sources (ten of which are not found in existing gamma-ray catalogs).
We combine these observations with the predicted pulsar formation rate based on
the stellar encounter rate of each globular cluster to constrain the gamma-ray
luminosity function of millisecond pulsars in the Milky Way's globular cluster
system. We find that this pulsar population exhibits a luminosity function that
is quite similar to those millisecond pulsars observed in the field of the
Milky Way (i.e. the thick disk). After pulsars are expelled from a globular
cluster, however, they continue to lose rotational kinetic energy and become
less luminous, causing their luminosity function to depart from the
steady-state distribution. Using this luminosity function and a model for the
globular cluster disruption rate, we show that millisecond pulsars born in
globular clusters can account for only a few percent or less of the observed
GeV excess. Among other challenges, scenarios in which the entire GeV excess is
generated from such pulsars are in conflict with the observed mass of the Milky
Way's Central Stellar Cluster.

categories: astro-ph.HE astro-ph.CO astro-ph.GA hep-ph


title:
SPARC: Mass Models for 175 Disk Galaxies with Spitzer Photometry and
  Accurate Rotation Curves

abstract:
  We introduce SPARC (Spitzer Photometry & Accurate Rotation Curves): a sample
of 175 nearby galaxies with new surface photometry at 3.6 um and high-quality
rotation curves from previous HI/Halpha studies. SPARC spans a broad range of
morphologies (S0 to Irr), luminosities (~5 dex), and surface brightnesses (~4
dex). We derive [3.6] surface photometry and study structural relations of
stellar and gas disks. We find that both the stellar mass-HI mass relation and
the stellar radius-HI radius relation have significant intrinsic scatter, while
the HI mass-radius relation is extremely tight. We build detailed mass models
and quantify the ratio of baryonic-to-observed velocity (Vbar/Vobs) for
different characteristic radii and values of the stellar mass-to-light ratio
(M/L) at [3.6]. Assuming M/L=0.5 Msun/Lsun (as suggested by stellar population
models) we find that (i) the gas fraction linearly correlates with total
luminosity, (ii) the transition from star-dominated to gas-dominated galaxies
roughly corresponds to the transition from spiral galaxies to dwarf irregulars
in line with density wave theory; and (iii) Vbar/Vobs varies with luminosity
and surface brightness: high-mass, high-surface-brightness galaxies are nearly
maximal, while low-mass, low-surface-brightness galaxies are submaximal. These
basic properties are lost for low values of M/L=0.2 Msun/Lsun as suggested by
the DiskMass survey. The mean maximum-disk limit in bright galaxies is M/L=0.7
Msun/Lsun at [3.6]. The SPARC data are publicly available and represent an
ideal test-bed for models of galaxy formation.


title:
Metal flows of the circumgalactic medium, and the metal budget in
  galactic halos

abstract:
  We present an analysis of the flow of metals through the circumgalactic
medium (CGM) in the Feedback in Realistic Environments (FIRE) simulations of
galaxy formation, ranging from isolated dwarfs to $L*$ galaxies. We find that
nearly all metals produced in high-redshift galaxies are carried out in winds
that reach $0.25 R_{\rm vir}$. When measured at $0.25 R_{\rm vir}$ the
metallicity of outflows is slightly higher than the interstellar medium (ISM)
metallicity. Many metals thus reside in the CGM. Cooling and recycling from
this reservoir determine the metal budget in the ISM. The outflowing metal flux
decreases by a factor of $\sim2-5$ between $0.25 R_{\rm vir}$ and $R_{\rm
vir}$. Furthermore, outflow metallicity is typically lower at $R_{\rm vir}$
owing to dilution of the remaining outflow by metal-poor material swept up from
the CGM. The inflow metallicity at $R_{\rm vir}$ is generally low, but outflow
and inflow metallicities are similar in the inner halo. At low redshift,
massive galaxies no longer generate outflows that reach the CGM, causing a
divergence in CGM and ISM metallicity. Dwarf galaxies continue to generate
outflows, although they preferentially retain metal ejecta. In all but the
least massive galaxy considered, a majority of the metals are within the halo
at $z=0$. We measure the fraction of metals in CGM, ISM and stars, and quantify
the thermal state of CGM metals in each halo. The total amount of metals in the
low-redshift CGM of two simulated $L*$ galaxies is consistent with estimates
from the COS halos survey, while for the other two it appears to be lower.


title: Constraining Light-Quark Yukawa Couplings from Higgs Distributions

abstract:
  We propose a novel strategy to constrain the bottom and charm Yukawa
couplings by exploiting LHC measurements of transverse momentum distributions
in Higgs production. Our method does not rely on the reconstruction of
exclusive final states or heavy-flavour tagging. Compared to other proposals it
leads to an enhanced sensitivity to the Yukawa couplings due to distortions of
the differential Higgs spectra from emissions which either probe quark loops or
are associated to quark-initiated production. We derive constraints using data
from LHC Run I, and we explore the prospects of our method at future LHC runs.
Finally, we comment on the possibility of bounding the strange Yukawa coupling.


title:
The Herschel-ATLAS Data Release 1 Paper II: Multi-wavelength
  counterparts to submillimetre sources

abstract:
  This paper is the second in a pair of articles presenting data release 1
(DR1) of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), the
largest single open-time key project carried out with the Herschel Space
Observatory. The H-ATLAS is a wide-area imaging survey carried out in five
photometric bands at 100, 160, 250, 350 and 500$\mu$m covering a total area of
600deg$^2$. In this paper we describe the identification of optical
counterparts to submillimetre sources in DR1, comprising an area of 161 deg$^2$
over three equatorial fields of roughly 12$^\circ$x4.5$^\circ$ centred at
9$^h$, 12$^h$ and 14.5$^h$ respectively. Of all the H-ATLAS fields, the
equatorial regions benefit from the greatest overlap with current
multi-wavelength surveys spanning ultraviolet (UV) to mid-infrared regimes, as
well as extensive spectroscopic coverage. We use a likelihood-ratio technique
to identify SDSS counterparts at r<22.4 for 250-$\mu$m-selected sources
detected at $\geq$ 4$\sigma$ ($\approx$28mJy). We find `reliable' counterparts
(reliability R$\geq$0.8) for 44,835 sources (39 per cent), with an estimated
completeness of 73.0 per cent and contamination rate of 4.7 per cent. Using
redshifts and multi-wavelength photometry from GAMA and other public
catalogues, we show that H-ATLAS-selected galaxies at $z<0.5$ span a wide range
of optical colours, total infrared (IR) luminosities, and IR/UV ratios, with no
strong disposition towards mid-IR-classified AGN in comparison with optical
selection. The data described herein, together with all maps and catalogues
described in the companion paper (Valiante et al. 2016), are available from the
H-ATLAS website at www.h-atlas.org.


title:
Interaction effects in superconductor/quantum spin Hall devices:
  universal transport signatures and fractional Coulomb blockade

abstract:
  Interfacing s-wave superconductors and quantum spin Hall edges produces
time-reversal-invariant topological superconductivity of a type that can not
arise in strictly 1D systems. With the aim of establishing sharp fingerprints
of this novel phase, we use renormalization group methods to extract universal
transport characteristics of superconductor/quantum spin Hall heterostructures
where the native edge states serve as leads. We determine scaling forms for the
conductance through a grounded superconductor and show that the results depend
sensitively on the interaction strength in the leads, the size of the
superconducting region, and the presence or absence of time-reversal-breaking
perturbations. We also study transport across a floating superconducting island
isolated by magnetic barriers. Here we predict e-periodic Coulomb-blockade
peaks, as recently observed in nanowire devices [Albrecht et al., Nature 531,
206 (2016)], with the added feature that the island can support fractional
charge tunable via the relative orientation of the barrier magnetizations. As
an interesting corollary, when the magnetic barriers arise from strong
interactions at the edge that spontaneously break time-reversal symmetry, the
Coulomb-blockade periodicity changes from e to e/2. These findings suggest
several future experiments that probe unique characteristics of topological
superconductivity at the quantum spin Hall edge.


title:
Lost and found: evidence of Second Generation stars along the Asymptotic
  Giant Branch of the globular cluster NGC 6752

abstract:
  We derived chemical abundances for C, N, O, Na, Mg and Al in 20 asymptotic
giant branch (AGB) stars in the globular cluster NGC 6752. All these elements
(but Mg) show intrinsic star-to-star variations and statistically significant
correlations or anticorrelations analogous to those commonly observed in red
giant stars of globular clusters hosting multiple populations. This
demonstrates that, at odds with previous findings, both first and second
generation stars populate the AGB of NGC 6752. The comparison with the Na
abundances of red giant branch stars in the same cluster reveals that second
generation stars (with mild Na and He enrichment) do reach the AGB phase. The
only objects that are not observed along the AGB of NGC 6752 are stars with
extreme Na enhancement. This is also consistent with standard stellar evolution
models, showing that highly Na and He enriched stars populate the bluest
portion of the horizontal branch and, because of their low stellar masses,
evolve directly to the white dwarf cooling sequence, skipping the AGB phase.


title: Bubble diagram through the Symmetries of Feynman Integrals method

abstract:
  The Symmetries of Feynman Integrals method (SFI) associates a natural Lie
group with any diagram, depending only on its topology. The group acts on
parameter space and the method determines the integral's dependence within
group orbits. This paper analyzes the bubble diagram, namely the 1-loop
propagator diagram, through the SFI method. This is the first diagram with
external legs to be analyzed within SFI, and the method is generalized to
include this case. The set of differential equation is obtained. In order to
solve it the set is transformed into partially invariants variables. The
equations are integrated to reproduce the integral's value. This value is
interpreted in terms of triangle geometry suggested by extant papers.


title: Lattice field theory applications in high energy physics

abstract:
  Lattice gauge theory was formulated by Kenneth Wilson in 1974. In the ensuing
decades, improvements in actions, algorithms, and computers have enabled
tremendous progress in QCD, to the point where lattice calculations can yield
sub-percent level precision for some quantities. Beyond QCD, lattice methods
are being used to explore possible beyond the standard model (BSM) theories of
dynamical symmetry breaking and supersymmetry. We survey progress in extracting
information about the parameters of the standard model by confronting lattice
calculations with experimental results and searching for evidence of BSM
effects.


title:
Formation of Andromeda II via a gas-rich major merger and an interaction
  with M31

abstract:
  Andromeda II (And II) has been known for a few decades but only recently
observations have unveiled new properties of this dwarf spheroidal galaxy. The
presence of two stellar populations, the bimodal star formation history (SFH)
and an unusual rotation velocity of And II put strong constrains on its
formation and evolution. Following Lokas et al. (2014), we propose a detailed
model to explain the main properties of And II involving (1) a gas-rich major
merger between two dwarf galaxies at high redshift in the field and (2) a close
interaction with M31 about 5 Gyr ago. The model is based on
N-body/hydrodynamical simulations including gas dynamics, star formation and
feedback. One simulation is designed to reproduce the gas-rich major merger
explaining the origin of stellar populations and the SFH. Other simulations are
used to study the effects of tidal forces and the ram pressure stripping during
the interaction between And II and M31. The model successfully reproduces the
SFH of And II including the properties of stellar populations, its morphology,
kinematics and the lack of gas. Further improvements to the model are possible
via joint modelling of all processes and better treatment of baryonic physics.


title: K stability and stability of chiral ring

abstract:
  We define a notion of stability for chiral ring of four dimensional N=1
theory by introducing test chiral rings and generalized a maximization. We
conjecture that a chiral ring is the chiral ring of a superconformal field
theory if and only if it is stable. We then study N=1 field theory derived from
D3 branes probing a three-fold singularity X, and show that the K stability
which implies the existence of Ricci-flat conic metric on X is equivalent to
the stability of chiral ring of the corresponding field theory.


title: Searching for supergiant fast X-ray transients with Swift

abstract:
  Supergiant fast X-ray transients (SFXTs) are high mass X-ray binaries (HMXBs)
hosting a neutron star and an OB supergiant companion. We examine the available
Swift data, as well as other new or archival/serendipitous data, on three
sources: IGR J17407-2808, 2XMM J185114.3-000004, and IGR J18175-2419, whose
X-ray characteristics qualify them as candidate SFXT, in order to explore their
properties and test whether they are consistent with an SFXT nature. As IGR
J17407-2808 and 2XMM J185114.3-000004 triggered the Burst Alert Telescope on
board Swift, the Swift data allow us to provide their first arcsecond
localisations, leading to an unequivocal identification of the source CXOU
J174042.0-280724 as the soft X-ray counterpart of IGR J17407-2808, as well as
their first broadband spectra, which can be fit with models generally
describing accreting neutron stars in HMXBs. While still lacking optical
spectroscopy to assess the spectral type of the companion, we propose 2XMM
J185114.3-000004 as a very strong SFXT candidate. The nature of IGR J17407-2808
remains, instead, more uncertain. Its broad band properties cannot exclude that
the emission originates from either a HMXB (and in that case, a SFXT) or, more
likely, a low mass X-ray binary. Finally, based on the deep non-detection in
our XRT monitoring campaign and a careful reanalysis of the original Integral
data in which the discovery of the source was first reported, we show that IGR
J18175-2419 is likely a spurious detection.


title:
Improved superconducting qubit coherence with high-temperature substrate
  annealing

abstract:
  We assess independently the impact of high-temperature substrate annealing
and metal deposition conditions on the coherence of transmon qubits in the
standard 2D circuit-QED architecture. We restrict our study to devices made
with aluminum interdigital capacitors on sapphire substrates. We record more
than an order-of-magnitude improvement in the relaxation time of devices made
with an annealed substrate, independent of whether a conventional evaporator or
molecular beam epitaxy chamber was used to deposit the aluminum. We also infer
similar levels of flux noise and photon shot noise through dephasing
measurements on these devices. Our results indicate that substrate annealing
plays a primary role in fabricating low-loss qubits, consistent with the
hypothesis that substrate-air and substrate-metal interfaces are essential
factors limiting the qubit lifetimes in superconducting circuits.


title:
Unravelling Quantum Dot Array Simulators via Singlet-Triplet
  Measurements

abstract:
  Recently, singlet-triplet measurements in double dots have emerged as a
powerful tool in quantum information processing. In parallel, quantum dot
arrays are being envisaged as analog quantum simulators of many-body models.
Thus motivated, we explore the potential of the above singlet-triplet
measurements for probing and exploiting the ground-state of a Heisenberg spin
chain in such a quantum simulator. We formulate an efficient protocol to
discriminate the achieved many-body ground-state with other likely states.
Moreover, the transition between quantum phases, arising from the addition of
frustrations in a $J_1-J_2$ model, can be systematically explored using the
same set of measurements. We show that the proposed measurements have an
application in producing long distance heralded entanglement between well
separated quantum dots. Relevant noise sources, such as non-zero temperatures
and nuclear spin interactions, are considered.


title:
How smart does your profile image look? Estimating intelligence from
  social network profile images

abstract:
  Profile images on social networks are users' opportunity to present
themselves and to affect how others judge them. We examine what Facebook images
say about users' perceived and measured intelligence. 1,122 Facebook users
completed a matrices intelligence test and shared their current Facebook
profile image. Strangers also rated the images for perceived intelligence. We
use automatically extracted image features to predict both measured and
perceived intelligence. Intelligence estimation from images is a difficult task
even for humans, but experimental results show that human accuracy can be
equalled using computing methods. We report the image features that predict
both measured and perceived intelligence, and highlight misleading features
such as "smiling" and "wearing glasses" that are correlated with perceived but
not measured intelligence. Our results give insights into inaccurate
stereotyping from profile images and also have implications for privacy,
especially since in most social networks profile images are public by default.


title: A growth-rate indicator for Compton-thick active galactic nuclei

abstract:
  Due to their heavily obscured central engines, the growth rate of
Compton-thick (CT) active galactic nuclei (AGN) is difficult to measure. A
statistically significant correlation between the Eddington ratio,
{\lambda}$_{Edd}$, and the X-ray power-law index, {\Gamma}, observed in
unobscured AGN offers an estimate of their growth rate from X-ray spectroscopy
(albeit with large scatter). However, since X-rays undergo reprocessing by
Compton scattering and photoelectric absorption when the line-of-sight to the
central engine is heavily obscured, the recovery of the intrinsic {\Gamma} is
challenging. Here we study a sample of local, predominantly Compton-thick
megamaser AGN, where the black hole mass, and thus Eddington luminosity, are
well known. We compile results on X-ray spectral fitting of these sources with
sensitive high-energy (E> 10 keV) NuSTAR data, where X-ray torus models which
take into account the reprocessing effects have been used to recover the
intrinsic {\Gamma} values and X-ray luminosities, L$_X$. With a simple
bolometric correction to L$_X$ to calculate {\lambda}$_{Edd}$, we find a
statistically significant correlation between {\Gamma} and {\lambda}$_{Edd}$ (p
= 0.007). A linear fit to the data yields {\Gamma} =
(0.41$\pm$0.18)log$_{10}${\lambda}$_{Edd}$+(2.38$\pm$ 0.20), which is
statistically consistent with results for unobscured AGN. This result implies
that torus modeling successfully recovers the intrinsic AGN parameters. Since
the megamasers have low-mass black holes (M$_{BH}\approx10^6-10^7$ M$_{sol}$)
and are highly inclined, our results extend the {\Gamma}-{\lambda}$_{Edd}$
relationship to lower masses and argue against strong orientation effects in
the corona, in support of AGN unification. Finally this result supports the use
of {\Gamma} as a growth-rate indicator for accreting black holes, even for
Compton-thick AGN.


title: A Discrete Regularization Method for Ill-Posed Operaror Equations

abstract:
  Discrete regularization methods are often applied for obtaining stable
approximate solutions for ill-posed operator equations $Tx=y$, where $T: X\to
Y$ is a bounded operator between Hilbert spaces with non-closed range $R(T)$
and $y\in R(T)$. Most of the existing such methods involve finite rank bounded
projection operators on either the domain space $X$ or on codomain space $Y$ or
on both. In this paper, we propose a discrete regularization based on finite
rank projection-like operators on some subspace of the codomain space such that
their ranges need not be subspaces of the codomain space. This method not only
incudes some of the exisiting projection based methods but also a quadrature
based collocation method considered by the author in \cite{mtn-acm} for
integral equations of the firt kind.


title:
Direct Observation of Dynamic Symmetry Breaking above Room Temperature
  in Methylammonium Lead Iodide Perovskite

abstract:
  Lead halide perovskites such as methylammonium lead triiodide (MAPI) have
outstanding optical and electronic properties for photovoltaic applications,
yet a full understanding of how this solution processable material works so
well is currently missing. Previous research has revealed that MAPI possesses
multiple forms of static disorder regardless of preparation method, which is
surprising in light of its excellent performance. Using high energy resolution
inelastic X-ray (HERIX) scattering, we measure phonon dispersions in MAPI and
find direct evidence for another form of disorder in single crystals: large
amplitude anharmonic zone-edge rotational instabilities of the PbI_6 octahedra
that persist to room temperature and above, left over from structural phase
transitions that take place tens to hundreds of degrees below. Phonon
calculations show that the orientations of the methylammonium couple strongly
and cooperatively to these modes. The result is a non-centrosymmetric,
instantaneous local structure, which we observe in atomic pair distribution
function (PDF) measurements. This local symmetry breaking is unobservable by
Bragg diffraction, but can explain key material properties such as the
structural phase sequence, ultra low thermal transport, and large minority
charge carrier lifetimes despite moderate carrier mobility.


title: Precision Measurement of sin2(theta_w) at MESA

abstract:
  A forthcoming experiment of low-energy elastic electron proton scattering at
the new MESA facility in Mainz is planned to provide a high-precision
measurement of the parity-violating polarisation asymmetry. This experiment is
expected to lead to a precision determination of the weak mixing angle,
competitive with Z-pole data. We discuss the challenges for theory to derive
predictions with the required accuracy.


title: Almost regular Poisson manifolds and their holonomy groupoids

abstract:
  We look at Poisson geometry taking the viewpoint of singular foliations,
understood as suitable submodules generated by Hamiltonian vector fields rather
than partitions into (symplectic) leaves. The class of Poisson structures which
behave best from this point of view, are those whose submodule generated by
Hamiltonian vector fields arises from a smooth holonomy groupoid. We call them
almost regular Poisson structures and determine them completely. They include
regular Poisson and log symplectic manifolds, as well as several other Poisson
structures whose symplectic foliation presents singularities.
  We show that the holonomy groupoid associated with an almost regular Poisson
structure is a Poisson groupoid, integrating a naturally associated Lie
bialgebroid. The Poisson structure on the holonomy groupoid is regular, and as
such it provides a desingularization. The holonomy groupoid is "minimal" among
Lie groupoids which give rise to the submodule generated by Hamiltonian vector
fields. This implies that, in the case of log-symplectic manifolds, the
holonomy groupoid coincides with the symplectic groupoid constructed by
Gualtieri and Li. Last, we focus on the integrability of almost regular Poisson
manifolds and exhibit the role of the second homotopy group of the
source-fibers of the holonomy groupoid.


title:
Kinodynamic Motion Planning: A Novel Type Of Nonlinear, Passive Damping
  Forces And Advantages

abstract:
  This article extends the capabilities of the harmonic potential field
approach to planning to cover both the kinematic and dynamic aspects of a robot
motion. The suggested approach converts the gradient guidance field from a
harmonic potential to a control signal by augmenting it with a novel type of
damping forces called nonlinear, anisotropic, damping forces. The combination
of the two provides a signal that can both guide a robot and effectively manage
its dynamics. The kinodynamic planning signal inherits the guidance
capabilities of the harmonic gradient field. It can also be easily configured
to efficiently suppress the inertia-induced transients in the robot trajectory
without compromising the speed of operation. The approach works with
dissipative systems as well as systems acted on by external forces without
needing the full knowledge of the system dynamics. Theoretical developments and
simulation results are provided in this article.


title: Gauge theory and G2-geometry on Calabi-Yau links

abstract:
  The $7$-dimensional link $K$ of a weighted homogeneous hypersurface on the
round $9$-sphere in $\mathbb{C}^5$ has a nontrivial null Sasakian structure
which is contact Calabi-Yau, in many cases. It admits a canonical co-closed
$\rm G_2$-structure $\varphi$ induced by the Calabi-Yau $3$-orbifold basic
geometry. We distinguish these pairs $(K,\varphi)$ by the Crowley-Nordstr\"om
$\mathbb{Z}_{48}$-valued $\nu$ invariant, for which we prove odd parity and
provide an algorithmic formula. We describe moreover a natural Yang-Mills
theory on such spaces, with many important features of the torsion-free case,
such as a Chern-Simons formalism and topological energy bounds. In fact
compatible $\rm G_2$-instantons on holomorphic Sasakian bundles over $K$ are
exactly the transversely Hermitian Yang-Mills connections. As a proof of
principle, we obtain $\rm G_2$-instantons over the Fermat quintic link from
stable bundles over the smooth projective Fermat quintic, thus relating in a
concrete example the Donaldson-Thomas theory of the quintic threefold with a
conjectural $\rm G_2$-instanton count.


title:
Towards a high-supersaturation theory of crystal growth: Nonlinear
  one-step flow model in 1+1 dimensions

abstract:
  Starting with a many-atom master equation of a kinetic, restricted
solid-on-solid (KRSOS) model with external material deposition, we investigate
nonlinear aspects of the passage to a mesoscale description for a crystal
surface in 1+1 dimensions. This latter description focuses on the motion of an
atomic line defect (i.e. a step), which is defined via appropriate statistical
average over KRSOS microstates. Near thermodynamic equilibrium and for low
enough supersaturation, we show that this mesoscale picture is reasonably
faithful to the Burton-Cabrera-Frank (BCF) step-flow model. More specifically,
we invoke a maximum principle in conjunction with asymptotic error estimates to
derive the elements of the BCF model: (i) a diffusion equation for the density
of adsorbed adatoms; (ii) a step velocity law; and (iii) a linear relation for
the mass flux of adatoms at the step. In this vein, we also provide a criterion
by which the adatom flux remains linear in supersaturation, suggesting a range
of non-equilibrium conditions under which the BCF model remains valid. Lastly,
we make use of kinetic Monte Carlo simulations to numerically study effects
that drive the system to higher supersaturations -- e.g. deposition of material
onto the surface from above. Using these results, we describe empirical
corrections to the BCF model that amount to a nonlinear relation for the adatom
flux at the step edge.


title:
Gravity-induced four-fermion contact interaction implies gravitational
  intermediate W and Z type gauge bosons

abstract:
  Coupling fermions to gravity necessarily leads to a non-renormalizable,
gravitational four-fermion contact interaction. In this essay, we argue that
augmenting the Einstein-Cartan Lagrangian with suitable kinetic terms quadratic
in the gravitational gauge field strengths (torsion and curvature) gives rise
to new, massive propagating gravitational degrees of freedom. This is to be
seen in close analogy to Fermi's effective four-fermion interaction and its
emergent W and Z bosons.


title: Compression of Neural Machine Translation Models via Pruning

abstract:
  Neural Machine Translation (NMT), like many other deep learning domains,
typically suffers from over-parameterization, resulting in large storage sizes.
This paper examines three simple magnitude-based pruning schemes to compress
NMT models, namely class-blind, class-uniform, and class-distribution, which
differ in terms of how pruning thresholds are computed for the different
classes of weights in the NMT architecture. We demonstrate the efficacy of
weight pruning as a compression technique for a state-of-the-art NMT system. We
show that an NMT model with over 200 million parameters can be pruned by 40%
with very little performance loss as measured on the WMT'14 English-German
translation task. This sheds light on the distribution of redundancy in the NMT
architecture. Our main result is that with retraining, we can recover and even
surpass the original performance with an 80%-pruned model.


title:
A Harmonic Potential Approach For Simultaneous Planning And Control Of A
  Generic UAV Platform

abstract:
  Simultaneous planning and control of a large variety of unmanned aerial
vehicles (UAVs) is tackled using the harmonic potential field (HPF) approach. A
dense reference velocity field generated from the gradient of an HPF is used to
regulate the velocity of the UAV concerned in a manner that would propel the
UAV to a target point while enforcing the constraints on behavior that were a
priori encoded in the reference field. The regulation process is carried-out
using a novel and simple concept called the: virtual velocity attractor (VVA).
The combined effect of the HPF gradient and the VVA is found able to yield an
efficient, easy to implement, well-behaved and provably-correct
context-sensitive control action that suits a wide variety of UAVs. The
approach is developed and basic proofs of correctness are provided along with
simulation results.


title:
Theory of enhanced interlayer tunneling in optically driven high $T_c$
  superconductors

abstract:
  Motivated by recent pump-probe experiments indicating enhanced coherent
$c$-axis transport in underdoped YBCO, we study Josephson junctions
periodically driven by optical pulses. We propose a mechanism for this
observation by demonstrating that a parametrically driven Josephson junction
shows an enhanced imaginary part of the low-frequency conductivity when the
driving frequency is above the plasma frequency, implying an effectively
enhanced Josephson coupling. We generalize this analysis to a bilayer system of
Josephson junctions modeling YBCO. Again, the Josephson coupling is enhanced
when the pump frequency is blue-detuned to either of the two plasma frequencies
of the material. We show that the emergent driven state is a genuine,
non-equilibrium superconducting state, in which equilibrium relations between
the Josephson coupling, current fluctuations, and the critical current no
longer hold.


title:
Response and noise correlations to complex natural sounds in the
  auditory midbrain

abstract:
  How natural communication sounds are spatially represented across the
inferior colliculus, the main center of convergence for auditory information in
the midbrain, is not known. The neural representation of the acoustic stimuli
results from the interplay of locally differing input and the organization of
spectral and temporal neural preferences that change gradually across the
nucleus. This raises the question how similar the neural representation of the
communication sounds is across these gradients of neural preferences, and
whether it also changes gradually. Multi-unit cluster spike trains were
recorded from guinea pigs presented with a spectrotemporally rich set of eleven
species-specific communication sounds. Using cross-correlation, we analyzed the
response similarity of spiking activity across a broad frequency range for
similarly and differently frequency-tuned neurons. Furthermore, we separated
the contribution of the stimulus to the correlations to investigate whether
similarity is only attributable to the stimulus, or, whether interactions exist
between the multi-unit clusters that lead to correlations and whether these
follow the same representation as the response similarity. We found that
similarity of responses is dependent on the neurons' spatial distance for
similarly and differently frequency-tuned neurons, and that similarity
decreases gradually with spatial distance. Significant neural correlations
exist, and contribute to the response similarity. Our findings suggest that for
multi-unit clusters in the mammalian inferior colliculus, the gradual response
similarity with spatial distance to natural complex sounds is shaped by neural
interactions and the gradual organization of neural preferences.


title: Motion Planning With Gamma-Harmonic Potential Fields

abstract:
  This paper extends the capabilities of the harmonic potential field (HPF)
approach to planning. The extension covers the situation where the workspace of
a robot cannot be segmented into geometrical subregions where each region has
an attribute of its own. The suggested approach uses a task-centered,
probabilistic descriptor of the workspace as an input to the planner. This
descriptor is processed, along with a goal point, to yield the navigation
policy needed to steer the agent from any point in its workspace to the target.
The approach is easily adaptable to planning in a cluttered environment
containing a vector drift field. The extension of the HPF approach is based on
the physical analogy with an electric current flowing in a nonhomogeneous
conducting medium. The resulting potential field is known as the gamma-harmonic
potential (GHPF). Proofs of the ability of the modified approach to avoid
zero-probability (definite threat) regions and to converge to the goal are
provided. The capabilities of the planer are demonstrated using simulation.


title:
The matching relaxation for a class of generalized set partitioning
  problems

abstract:
  This paper introduces a discrete relaxation for the class of combinatorial
optimization problems which can be described by a set partitioning formulation
under packing constraints. We present two combinatorial relaxations based on
computing maximum weighted matchings in suitable graphs. Besides providing dual
bounds, the relaxations are also used on a variable reduction technique and a
matheuristic. We show how that general method can be tailored to sample
applications, and also perform a successful computational evaluation with
benchmark instances of a problem in maritime logistics.


title:
On Symmetries in Time Optimal Control, sub-Riemannian Geometries and the
  K-P Problem

abstract:
  The goal of this paper is to describe a method to solve a class of time
optimal control problems which are equivalent to finding the sub-Riemannian
minimizing geodesics on a manifold M. In particular, we assume that the
manifold M is acted upon by a group G which is a symmetry group for the
dynamics. The action of G on M is proper but not necessarily free. As a
consequence, the orbit space M/G is not necessarily a manifold but it presents
the more general structure of a stratified space. The main ingredients of the
method are a reduction of the problem to the orbit space M/G and an analysis of
the reachable sets on this space. We give general results relating the
stratified structure of the orbit space, and its decomposition into orbit
types, with the optimal synthesis. We consider in more detail the case of the
so-called K-P problem where the manifold M is itself a Lie group and the group
G is determined by a Cartan decomposition of M. In this case, the geodesics can
be explicitly calculated and are analytic. As an illustration, we apply our
method and results to the complete optimal synthesis on SO(3).


title:
Multiphase Segmentation For Simultaneously Homogeneous and Textural
  Images

abstract:
  Segmentation remains an important problem in image processing. For
homogeneous (piecewise smooth) images, a number of important models have been
developed and refined over the past several decades. However, these models
often fail when applied to the substantially larger class of natural images
that simultaneously contain regions of both texture and homogeneity. This work
introduces a bi-level constrained minimization model for simultaneous
multiphase segmentation of images containing both homogeneous and textural
regions. We develop novel norms defined in different functional Banach spaces
for the segmentation which results in a non-convex minimization. Finally, we
develop a generalized notion of segmentation delving into approximation theory
and demonstrating that a more refined decomposition of these images results in
multiple meaningful components. Both theoretical results and demonstrations on
natural images are provided.


title: Learning without Forgetting

abstract:
  When building a unified vision system or gradually adding new capabilities to
a system, the usual assumption is that training data for all tasks is always
available. However, as the number of tasks grows, storing and retraining on
such data becomes infeasible. A new problem arises where we add new
capabilities to a Convolutional Neural Network (CNN), but the training data for
its existing capabilities are unavailable. We propose our Learning without
Forgetting method, which uses only new task data to train the network while
preserving the original capabilities. Our method performs favorably compared to
commonly used feature extraction and fine-tuning adaption techniques and
performs similarly to multitask learning that uses original task data we assume
unavailable. A more surprising observation is that Learning without Forgetting
may be able to replace fine-tuning with similar old and new task datasets for
improved new task performance.


title:
Shapiro Spikes and Negative Mobility for Skyrmion Motion on
  Quasi-One-Dimensional Periodic Substrates

abstract:
  Using a simple numerical model of skyrmions in a two-dimensional system
interacting with a quasi-one dimensional periodic substrate under combined dc
and ac drives where the dc drive is applied perpendicular to the substrate
periodicity, we show that a rich variety of novel phase locking dynamics can
occur due to the influence of the Magnus term on the skyrmion dynamics. Instead
of Shapiro steps, the velocity response in the direction of the dc drive
exhibits a series of spikes, including extended dc drive intervals over which
the skyrmions move in the direction opposite to the dc drive, producing
negative mobility. There are also specific dc drive values at which the
skyrmions move exactly perpendicular to the dc drive direction, giving a
condition of absolute transverse mobility.


title: Relevant parameters in models of cell division control

abstract:
  A recent burst of dynamic single-cell growth-division data makes it possible
to characterize the stochastic dynamics of cell division control in bacteria.
Different modeling frameworks were used to infer specific mechanisms from such
data, but the links between frameworks are poorly explored, with relevant
consequences for how well any particular mechanism can be supported by the
data. Here, we describe a simple and generic framework in which two common
formalisms can be used interchangeably: (i) a continuous-time division process
described by a hazard function and (ii) a discrete-time equation describing
cell size across generations (where the unit of time is a cell cycle). In our
framework, this second process is a discrete-time Langevin equation with a
simple physical analogue. By perturbative expansion around the mean initial
size (or inter-division time), we show explicitly how this framework describes
a wide range of division control mechanisms, including combinations of time and
size control, as well as the constant added size mechanism recently found to
capture several aspects of the cell division behavior of different bacteria. As
we show by analytical estimates and numerical simulation, the available data
are characterized with great precision by the first-order approximation of this
expansion. Hence, a single dimensionless parameter defines the strength and the
action of the division control. However, this parameter may emerge from several
mechanisms, which are distinguished only by higher-order terms in our
perturbative expansion. An analytical estimate of the sample size needed to
distinguish between second-order effects shows that this is larger than what is
available in the current datasets. These results provide a unified framework
for future studies and clarify the relevant parameters at play in the control
of cell division.


title:
Constraining dust properties in Circumstellar Envelopes of C-stars in
  the Small Magellanic Cloud: optical constants and grain size of Carbon dust

abstract:
  We present a new approach aimed at constraining the typical size and optical
properties of carbon dust grains in Circumstellar envelopes (CSEs) of
carbon-rich stars (C-stars) in the Small Magellanic Cloud (SMC). To achieve
this goal, we apply our recent dust growth description, coupled with a
radiative transfer code to the CSEs of C-stars evolving along the TP-AGB, for
which we compute spectra and colors. Then we compare our modeled colors in the
near- and mid-infrared (NIR and MIR) bands with the observed ones, testing
different assumptions in our dust scheme and employing several data sets of
optical constants for carbon dust available in the literature. Different
assumptions adopted in our dust scheme change the typical size of the carbon
grains produced. We constrain carbon dust properties by selecting the
combination of grain size and optical constants which best reproduces several
colors in the NIR and MIR at the same time. The different choices of optical
properties and grain size lead to differences in the NIR and MIR colors greater
than two magnitudes in some cases. We conclude that the complete set of
observed NIR and MIR colors are best reproduced by small grains, with sizes
between $\sim$0.035 and $\sim$0.12~$\mu$m, rather than by large grains between
$\sim0.2$ and $0.7$~$\mu$m. The inability of large grains to reproduce NIR and
MIR colors seems independent of the adopted optical data set. We also find a
possible trend of the grain size with mass-loss and/or carbon excess in the
CSEs of these stars.


title: Axionic extension of the Einstein-aether theory

abstract:
  We extend the Einstein-aether theory to take into account the interaction
between a pseudoscalar field, which describes the axionic dark matter, and a
time-like dynamic unit vector field, which characterizes the velocity of the
aether motion. The Lagrangian of the Einstein-aether-axion theory includes
cross-terms based on the axion field and its gradient four-vector, on the
covariant derivative of the aether velocity four-vector, and on the Riemann
tensor and its convolutions. We follow the principles of the Effective Field
theory, and include into the Lagrangian of interactions all possible terms up
to the second order in the covariant derivative. Interpretation of new
couplings is given in terms of irreducible parts of the covariant derivative of
the aether velocity, namely, the acceleration four-vector, the shear and
vorticity tensors, and the expansion scalar. A spatially isotropic and
homogeneous cosmological model with dynamic unit vector field and axionic dark
matter is considered as an application of the established theory; new exact
solutions are discussed, which describe models with a Big Rip, Pseudo Rip and
de Sitter-type asymptotic behavior.


title: Improved model for the thermal conductivity of binary metallic systems

abstract:
  We extended and corrected Mott's two-band model for the
composition-dependence of thermal and electrical conductivity in binary metal
alloys based on high-throughput time-domain thermoreflectance (TDTR)
measurements on diffusion multiples and scatterer-density calculations from
first principles. Examining PdAg, PtRh, AuAg, AuCu, PdCu, PdPt, and NiRh binary
alloys, we found that the nature of the two dominant scatterer-bands considered
in the Mott model changes with the alloys, and should be interpreted as a
combination of the dominant element-specific s- and/or d-orbitals. Using
calculated orbital and element-resolved density-of-states values calculated
with density functional theory as input, we determined the correct orbital mix
that dominates electron scattering for all examined alloys and find excellent
agreement between fitted models and experiments. The proposed description of
the composition dependence of the resistivity can be readily implemented into
the CALPHAD framework.


title: Parameter estimation based on cumulative Kullback-Leibler divergence

abstract:
  In this paper, we propose some estimators for the parameters of a statistical
model based on Kullback-Leibler divergence of the survival function in
continuous setting. We prove that the proposed estimators are subclass of
"generalized estimating equations" estimators. The asymptotic properties of the
estimators such as consistency, asymptotic normality, asymptotic confidence
interval and asymptotic hypothesis testing are investigated.


title: Fitting EMC structure functions with intrinsic charm

abstract:
  A detailed study of the impact of the data collected by the European Muon
Collaboration (EMC) on the parton distribution function (PDF) of the charm
quark is presented. The analysis is performed in the NNPDF framework, and the
charm PDF is freely parametrized on equal footing as light quark and gluon
distributions. We find that variations in the treatment of EMC data do not
modify the charm PDF and do not affect our previous conclusion on the presence
of an intrinsic component in the charm PDF.


title:
Deterministic construction of arbitrary $W$ states with quadratically
  increasing number of two-qubit gates

abstract:
  We propose a quantum circuit composed of $cNOT$ gates and four single-qubit
gates to generate a $W$ state of three qubits. This circuit was then enhanced
by integrating two-qubit gates to create a $W$ state of four and five qubits.
After a couple of enhancements, we show that an arbitrary $W$ state can be
generated depending only on the degree of enhancement. The generalized formula
for the number of two-qubit gates required is given, showing that an $n$-qubit
$W$-state generation can be achieved with quadratically increasing number of
two-qubit gates. Also, the practical feasibility is discussed regarding photon
sources and various applications of $cNOT$ gates.


title: Physics of ultrathin films and heterostructures of rare earth nickelates

abstract:
  The electronic structure of transition metal oxides featuring correlated
electrons can be rationalized within the Zaanen-Sawatzky-Allen framework.
Following a brief description of the present paradigms of electronic behavior,
we focus on the physics of rare earth nickelates as an archetype of complexity
emerging within the charge transfer regime. The intriguing prospect of
realizing the physics of high $T_c$ cuprates through heterostructuring resulted
in a massive endeavor to epitaxially stabilize these materials in ultra-thin
form. A plethora of new phenomena unfolded in such artificial structures due to
the effect of epitaxial strain, quantum confinement, and interfacial charge
transfer. Here we review the present status of artificial rare-earth nickelates
in an effort to uncover the interconnection between the electronic and magnetic
behavior and the underlying crystal structure. We conclude by discussing future
directions to disentangle the puzzle regarding the origin of the
metal-insulator transition, the role of oxygen holes, and the true nature of
the antiferromagnetic spin configuration in the ultra-thin limit.


title:
Radiative Symmetry Breaking in Supersymmetric $B-L$ Models with Inverse
  Seesaw

abstract:
  We study the radiative symmetry breaking of B-L in supersymmetric models with
inverse seesaw mechanism. We show that for a wide region of parameter space the
radiative corrections can drive the squared mass of the extra Higgs boson from
positive initial values at the GUT scale to negative values at the TeV scale,
leading to the spontaneous breaking of the B-L symmetry. We also emphasize that
in this class of models, unlike the supersymmetric B-L models with type I
seesaw, the right-handed sneutrino cannot get a non-zero vacuum expectation
value. Therefore, B-L can be radiatively broken while R-parity remains an exact
symmetry.