title: The evolutionary approach to understand human low fertility phenomenon

abstract:
  Is it possible to reverse the low total fertility rate (TFR) in the developed
world? Using a hypothetical model of population we have analysed the decline of
the TFR which have took place in the background of ongoing global economic
changes, and a liberalization process after the end of the Cold War. These
phenomena have affected more than 110 millions of inhabitants of Central Europe
and the Baltics and approximately 80 millions of inhabitants in Germany. The
model has features of complex and evolving system of interacting individuals,
and it enables to investigate a broad spectrum of input factors on individual
decisions to limit the offspring. In the case of the TFR <1.5, our initial
analysis show a need of radical changes of the global economy that will
stimulate series of self-regulations of demographic processes and evolution
toward the safe TFR>2.1. The changes should stimulate more uniform spatial
distribution of wealth, capital and usage. They will increase a number of
self-sufficient and cooperative territories, to decrease the income inequality,
to decrease labour and social mobilities. Societies should investigate the
impacts of economic regulations and actions on the TFR trends in advance and
take into account a biological nature of women more responsible.


title:
Bogoliubov depletion of the fragmented condensate in the bosonic flux
  ladder

abstract:
  We theoretically analyze the ground state of weakly interacting bosons in the
flux ladder -- the system that has been recently realized by means of ultacold
atoms in the specially designed optical lattice [M. Atala, et al., Nat. Phys.
10, 588 (2014)]. It is argued that, for the system parameters corresponding to
the so-called `vortex phase', the ground state is a fragmented condensate. We
study the Bogoliubov depletion of this condensate and discuss the role of
boundary conditions.


title: Probability and (Braiding) Statistics in Majorana nanowires

abstract:
  Given recent progress in the realization of Majorana zero modes in
semiconducting nanowires with proximity-induced superconductivity, a crucial
next step is to attempt an experimental demonstration of the predicted braiding
statistics associated with the Majorana mode. Such a demonstration should, in
principle, confirm that observed zero-bias anomalies are indeed indicative of
the presence of anyonic Majorana zero modes. Moreover, such a demonstration
would be a breakthrough at the level of fundamental physics: the first clear
demonstration of a non-Abelian excitation. It is therefore important to clarify
the expected signals of Majorana physics in the braiding context, and to
differentiate these signals from those that might also arise in non-topological
variants of the same system. A definitive and critical distinction between
signals expected in topological (i.e. anyonic) and non-topological (i.e.
trivial) situations is therefore essential for future progress in the field. In
this manuscript, we carefully examine the expected signals of braiding and
fusion experiments in topological and non-topological variants of the
experimental nanowire systems in which Majoranas are predicted to occur. We
point out situations where `trivial' and `anyonic' signatures may be similar
experimentally, necessitating a certain level of caution in the interpretation
of various proposed fusion and braiding experiments. We find in particular that
braiding experiments consisting of full braids (two Majorana exchanges) are
better at distinguishing between topological and non-topological systems than
fusion experiments or experiments with an odd number of Majorana exchanges.


title: Editorial: Emergence in driven solid-state and cold-atom systems

abstract:
  We briefly summarize the current status of driven solid-state and cold-atom
systems, and introduce articles compiled in the Focus Section in Zeitschrift
f\"ur Naturforschung A, Volume 71, Issue 10 (2016)


title: Generalized multi-Proca fields

abstract:
  We extend previous results on healthy derivative self-interactions for a
Proca field to the case of a set of massive vector fields. We obtain non-gauge
invariant derivative self-interactions for the vector fields that maintain the
appropriate number of propagating degrees of freedom. In view of the potential
cosmological applications, we restrict to interactions with an internal
rotational symmetry. We provide a systematical construction order by order in
derivatives of the fields and making use of the antisymmetric Levi-Civita
tensor. We then compare with the one single vector field case and show that the
interactions can be broadly divided into two groups, namely the ones obtained
from a direct extension of the generalized Proca terms and genuine multi-Proca
interactions with no correspondence in the single Proca case. We also discuss
the curved spacetime version of the interactions to include the necessary
non-minimal couplings to gravity. Finally, we explore the cosmological
applications and show that there are three different vector fields
configurations giving rise to isotropic solutions. Two of them have already
been considered in the literature and the third one, representing a combination
of the first two, is new and offers unexplored cosmological scenarios.


title:
Influence of topological constraints and topological excitations:
  Decomposition formulas for calculating homotopy groups of symmetry-broken
  phases

abstract:
  A symmetry broken phase of a system with internal degrees of freedom often
features a complex order parameter, which generates a rich variety of
topological excitations and imposes topological constraints on their
interaction (topological influence); yet the very complexity of the order
parameter makes it difficult to treat topological excitations and topological
influence systematically. To overcome this problem, we develop a general method
to calculate homotopy groups and derive decomposition formulas which express
homotopy groups of the order parameter manifold $G/H$ in terms of those of the
symmetry $G$ of a system and those of the remaining symmetry $H$ of the state.
By applying these formulas to general monopoles and three-dimensional
skyrmions, we show that their textures are obtained through substitution of the
corresponding $\mathfrak{su}(2)$-subalgebra for the $\mathfrak{su}(2)$-spin. We
also show that a discrete symmetry of $H$ is necessary for the presence of
topological influence and find topological influence on a skyrmion
characterized by a non-Abelian permutation group of three elements in the
ground state of an SU(3)-Heisenberg model.

categories: cond-mat.other cond-mat.mtrl-sci cond-mat.quant-gas cond-mat.stat-mech hep-th


title:
On embedded hidden Markov models and particle Markov chain Monte Carlo
  methods

abstract:
  The embedded hidden Markov model (EHMM) sampling method is a Markov chain
Monte Carlo (MCMC) technique for state inference in non-linear non-Gaussian
state-space models which was proposed in Neal (2003); Neal et al. (2004) and
extended in Shestopaloff and Neal (2016). An extension to Bayesian parameter
inference was presented in Shestopaloff and Neal (2013). An alternative class
of MCMC schemes addressing similar inference problems is provided by particle
MCMC (PMCMC) methods (Andrieu et al. 2009; 2010). All these methods rely on the
introduction of artificial extended target distributions for multiple state
sequences which, by construction, are such that one randomly indexed sequence
is distributed according to the posterior of interest. By adapting the
Metropolis-Hastings algorithms developed in the framework of PMCMC methods to
the EHMM framework, we obtain novel particle filter (PF)-type algorithms for
state inference and novel MCMC schemes for parameter and state inference. In
addition, we show that most of these algorithms can be viewed as particular
cases of a general PF and PMCMC framework. We compare the empirical performance
of the various algorithms on low- to high-dimensional state-space models. We
demonstrate that a properly tuned conditional PF with "local" MCMC moves
proposed in Shestopaloff and Neal (2016) can outperform the standard
conditional PF significantly when applied to high-dimensional state-space
models while the novel PF-type algorithm could prove to be an interesting
alternative to standard PFs for likelihood estimation in some lower-dimensional
scenarios.


title: Modeling a vehicular traffic network. Part I

abstract:
  We propose three models for the traffic of vehicles within a network formed
by sites (cities, car-rental agencies, parking lots, etc.) and connected by
two-way arteries (roads, highways), that allow forecasting the vehicular flux
in a sequence of $n$ consecutive steps, or units of time. An essential approach
consists in using, as an "a priori" information, previous observations and
measurements. The formal tools used in our analysis consists in: (1)
associating a digraph to the network where the edges correspond to arteries and
the vertices with loops represent the sites. (2) From an initial set of
numbers, that are the distribution of vehicles within the network, we construct
a matrix that we transform into a stochastic matrix (SM) by normalizing the
rows, whose entries are now transition probabilities. This matrix becomes the
generator of the evolution of the traffic flow. And (3), we use the
Perron-Frobenius theory for a formal analysis. We investigate three models: (a)
a closed four-site network having a conserved number of vehicles; (b) to this
network we add an influx and an outflux of vehicles to characterize an open
system; asymptotically, $n \rightarrow \infty$, the SM raised to the power $n$
goes to a unique stationary matrix. And (c), we construct a nonlinear model
because the formal structure permits the existence of several ($L$) stationary
states for the distribution of vehicles at each site, that alternate cyclically
with time. Each state represents the traffic for $L$ different moments. These
models were used to analyze the traffic in a sector of the city of Tigre,
located in the province of Buenos Aires, Argentina. The results are presented
in a following paper.


title:
Analytically continued physical states in the path-integral: a
  sign-problem-free Quantum Monte Carlo simulation of Bell states dynamics

abstract:
  The derivation of path integrals is reconsidered. It is shown that the
expression for the discretized action is not unique, and the path integration
domain can be deformed so that at least Gaussian path integrals become
probabillistic. This leads to a practical algorithm of sign-problem-free Monte
Carlo sampling from the Gaussian path integrals. Moreover, the dynamical
influence of Gaussian quantum system (the bath) on any other quantum system can
be exactly represented as interaction with classical non-Markovian noise. We
discuss the relation of these findings to the Bell's theorem and the Feynman's
conjecture on the exponential complexity of the classical simulation of quantum
systems. In Feynman's path integral we have quasiprobability distributions for
trajectories, and in analitycally continued path integrals we have probability
distributions for quasitrajectories.


title: Dynamical dark energy: scalar fields and running vacuum

abstract:
  Recent analyses in the literature suggest that the concordance $\Lambda$CDM
model with rigid cosmological term, $\Lambda=$const., may not be the best
description of the cosmic acceleration. The class of "running vacuum models",
in which $\Lambda=\Lambda(H)$ evolves with the Hubble rate, has been shown to
fit the string of $SNIa+BAO+H(z)+LSS+CMB$ data significantly better than the
$\Lambda$CDM. Here we provide further evidence on the time-evolving nature of
the dark energy (DE) by fitting the same cosmological data in terms of scalar
fields. As a representative model we use the original Peebles & Ratra
potential, $V\propto\Phi^{-\alpha}$. We find clear signs of dynamical DE at
$\sim 4\sigma$ c.l., thus reconfirming through a nontrivial scalar field
approach the strong hints formerly found with other models and
parametrizations.


title: The Ancient Astronomy of Easter Island: Aldebaran and the Pleiades

abstract:
  There is a good cause to assert that the Easter Islanders constantly watched
Aldebaran and the Pleiades in the past. The Russian scholar Irina K. Fedorova
and the American scholar Georgia Lee were the first who contributed
significantly to the archaeoastronomical studies of these celestial bodies. I
have decoded the Mataveri calendar completely. The ceremonial platform Hekii 2
was oriented on Aldebaran and nearby stars. The disappearance of the Pleiades
during the dawn period in the north at the end of August could be an important
mark before the arrival of sooty terns and before the elections of the next
bird-man. The calculated dates of several solar eclipses have been used for
composing the chronology of Easter Island from 1771 till 1867 A.D.


title:
Exact transparent boundary conditions for the parabolic wave equations
  with linear and quadratic potentials

abstract:
  In this paper exact 1D transparent boundary conditions (TBC) for the 2D
parabolic wave equation with a linear or a quadratic dependence of the
dielectric permittivity on the transversal coordinate are reported. Unlike the
previously derived TBCs they contain only elementary functions. The obtained
boundary conditions can be used to numerically solve the 2D parabolic equation
describing the propagation of light in weakly bent optical waveguides and
fibers including waveguides with variable curvature. They also are useful when
solving the equivalent 1D Schr\"odinger equation with a potential depending
linearly or quadratically on the coordinate. The prospects and problems of
discretization of the derived transparent boundary conditions are discussed.

categories: physics.class-ph math-ph math.MP physics.optics


title: Geometric Constraints from Subregion Duality Beyond the Classical Regime

abstract:
  Subregion duality in AdS/CFT implies certain constraints on the geometry:
entanglement wedges must contain causal wedges, and nested boundary regions
must have nested entanglement wedges. We elucidate the logical connections
between these statements and the Quantum Focussing Conjecture, Quantum Null
Energy Condition, Boundary Causality Condition, and Averaged Null Energy
Condition. Our analysis does not rely on the classical limit of bulk physics,
but instead works to all orders in $G\hbar \sim 1/N$. This constitutes a
nontrivial check on the consistency of subregion duality, entanglement wedge
reconstruction, and holographic entanglement entropy beyond the classical
regime.


title: Noncommutative coarse geometry

abstract:
  We use compactifications of C*-algebras to introduce noncommutative coarse
geometry. We transfer a noncommutative coarse structure on a C*-algebra with an
action of a locally compact Abelian group by translations to Rieffel
deformations and prove that the resulting noncommutative coarse spaces are
coarsely equivalent. We construct a noncommutative coarse structure from a
cocompact continuously square-integrable action of a group and show that this
is coarsely equivalent to the standard coarse structure on the group in
question. We define noncommutative coarse maps through certain completely
positive maps that induce *-homomorphisms on the boundaries of the
compactifications. We lift *-homomorphisms between separable, nuclear
boundaries to noncommutative coarse maps and prove an analogous lifting theorem
for maps between the metrisable boundaries of ordinary locally compact spaces.


title: Boundary Fluctuations and A Reduction Entropy

abstract:
  The boundary Weyl anomalies live on a codimension-1 boundary, $\partial {\cal
M}$. The entanglement entropy originates from infinite correlations on both
sides of a codimension-2 surface, $\Sigma$. Motivated to have a further
understanding of the boundary effects, we introduce a notion of reduction
entropy, which, guided by thermodynamics, is a combination of the boundary
effective action and the boundary stress tensor defined by allowing the metric
on $\partial {\cal M}$ to fluctuate. We discuss how a reduction might be
performed so that the reduction entropy reproduces the entanglement structure.


title: Quantifying Supernovae-Driven Multiphase Galactic Outflows

abstract:
  Galactic outflows are ubiquitously observed in star-forming disk galaxies and
are critical for galaxy formation. Supernovae (SNe) play the key role in
driving the outflows, but there is no consensus as to how much energy, mass and
metal they can launch out of the disk. We perform 3D, high-resolution
hydrodynamic simulations to study SNe-driven outflows from stratified media.
Assuming SN rate scales with gas surface density $\Sigma_{\rm{gas}}$ as in the
Kennicutt-Schmidt (KS) relation, we find the mass loading factor, $\eta_m$,
defined as the mass outflow flux divided by the star formation surface density,
decreases with increasing $\Sigma_{\rm{gas}}$ as $\eta_m \propto
\Sigma^{-0.61}_{\rm{gas}}$. Approximately $\Sigma_{\rm{gas}}$ $\lesssim$ 50
$M_\odot/\rm{pc}^2$ marks when $\eta_m \gtrsim$1. About 10-50\% of the energy
and 40-80\% of the metals produced by SNe end up in the outflows. The tenuous
hot phase ($T>3\times 10^5$ K), which fills 60-80\% of the volume at mid-plane,
carries the majority of the energy and metals in outflows. We discuss how
various physical processes, including vertical distribution of SNe,
photoelectric heating, external gravitational field and SN rate, affect the
loading efficiencies. The relative scale height of gas and SNe is a very
important factor in determining the loading efficiencies.


title: Is the expansion of the universe accelerating? All signs point to yes

abstract:
  The accelerating expansion of the universe is one of the most profound
discoveries in modern cosmology, pointing to a universe in which 70% of the
mass-energy density has an unknown form spread uniformly across the universe.
This result has been well established using a combination of cosmological
probes (e.g., Planck Collaboration et al. 2016), resulting in a "standard
model" of modern cosmology that is a combination of a cosmological constant
with cold dark matter and baryons. The first compelling evidence for the
acceleration came in the late 1990's, when two independent teams studying type
Ia supernovae discovered that distant SNe Ia were dimmer than expected. The
combined analysis of modern cosmology experiments, including SNe Ia, the Hubble
constant, baryon acoustic oscillations, and the cosmic microwave background has
now measured the contributions of matter and the cosmological constant to the
energy density of the universe to better than 0.01, providing a secure
measurement of acceleration. A recent study (Tr{\o}st Nielsen et al. 2015) has
claimed that the evidence for acceleration from SNe Ia is "marginal." Here we
demonstrate errors in that analysis which reduce the acceleration significance
from SNe Ia, and further demonstrate that conservative constraints on the
curvature or matter density of the universe increase the significance even
more. Analyzing the Joint Light-curve Analysis supernova sample, we find
4.2{\sigma} evidence for acceleration with SNe Ia alone, and 11.2{\sigma} in a
flat universe. With our improved supernova analysis and by not rejecting all
other cosmological constraints, we find that acceleration is quite secure.


title:
Global Phase Diagram of a Dirty Weyl Liquid and Emergent
  Superuniversality

abstract:
  Pursuing complementary field-theoretic and numerical methods, we here paint
the global phase diagram of a three-dimensional dirty Weyl system. The
generalized Harris criterion, augmented by a perturbative renormalization-group
(RG) analysis shows that weak disorder is an irrelevant perturbation at the
Weyl semimetal(WSM)-insulator quantum critical point (QCP). But, a metallic
phase sets in through a quantum phase transition (QPT) at strong disorder
across a multicritical point (MCP). The field theoretic predictions for the
correlation length exponent $\nu=2$ and dynamic scaling exponent $z=5/4$ at
this MCP are in good agreement with the ones extracted numerically, yielding
$\nu=1.98 \pm 0.10$ and $z=1.26 \pm 0.05$, from the scaling of the average
density of states (DOS). Deep inside the WSM phase, generic disorder is also an
irrelevant perturbation, while a metallic phase appears at strong disorder
through a QPT. We here demonstrate that in the presence of generic, but strong
disorder the WSM-metal QPT is ultimately always characterized by the exponents
$\nu=1$ and $z=3/2$ (to one-loop order), originating from intra-node or chiral
symmetric (e.g., regular and axial potential) disorder. We here anchor such
emergent \emph{chiral superuniversality} through complementary RG calculations,
controlled via $\epsilon$-expansions, and numerical analysis of average DOS
across WSM-metal QPT. In addition, we also discuss a subsequent QPT (at even
stronger disorder) of a Weyl metal into an Anderson insulator by numerically
computing the typical DOS at zero energy. The scaling behavior of various
physical observables, such as residue of quasiparticle pole, dynamic
conductivity, specific heat, Gr$\ddot{\mbox{u}}$neisen ratio, inside various
phases as well as across various QPTs in the global phase diagram of a dirty
Weyl liquid are discussed.

categories: cond-mat.mes-hall cond-mat.dis-nn cond-mat.str-el hep-th


title:
A phylogenetic scan test on Dirichlet-tree multinomial model for
  microbiome data

abstract:
  In this paper we introduce the phylogenetic scan test (PhyloScan) for
investigating cross-group differences in microbiome compositions using the
Dirichlet-tree multinomial (DTM) model. DTM models the microbiome data through
a cascade of independent local DMs on the internal nodes of the phylogenetic
tree. Each of the local DMs captures the count distributions of a certain
number of operational taxonomic units at a given resolution. Since
distributional differences tend to occur in clusters along evolutionary
lineages, we design a scan statistic over the phylogenetic tree to allow nodes
to borrow signal strength from their parents and children. We also derive a
formula to bound the tail probability of the scan statistic, and verify its
accuracy through simulations. The PhyloScan procedure is applied to the
American Gut dataset to identify taxa associated with diet habits. Empirical
studies performed on this dataset show that PhyloScan achieves higher testing
power in most cases.


title: Correlated triple-Weyl semimetals with Coulomb interactions

abstract:
  We study interaction effects, including both long-ranged Coulomb and
short-range interactions, in three-dimensional topological triple-Weyl
semimetals whose triple-Weyl points are protected by crystal symmetries. By
performing Wilsonian renormalization group analysis of the low-energy effective
field theory of the minimal model with triple-Weyl nodes, we find that the
fixed point of noninteracting triple-Weyl fermions is unstable in the presence
of Coulomb interactions and flows to a nontrivial stable fixed point
representing marginal Fermi liquids with anisotropic screening effects. We
further discuss relevant unusual physical consequences due to the novel
behavior of correlation effects in this system.


title:
Coupling constant corrections in a holographic model of heavy ion
  collisions

abstract:
  We initiate a holographic study of coupling-dependent heavy ion collisions by
analysing for the first time the effects of leading-order, inverse coupling
constant corrections. In the dual description, this amounts to colliding
gravitational shock waves in a theory with curvature-squared terms. We find
that at intermediate coupling, nuclei experience less stopping and have more
energy deposited near the lightcone. When the decreased coupling results in an
80% larger shear viscosity, the time at which hydrodynamics becomes a good
description of the plasma created from high energy collisions increases by 25%.
The hydrodynamic phase of the evolution starts with a wider rapidity profile
and smaller entropy.


title: Correcting CIV-Based Virial Black Hole Masses

abstract:
  The CIV broad emission line is visible in optical spectra to redshifts
exceeding z~5. CIV has long been known to exhibit significant displacements to
the blue and these `blueshifts' almost certainly signal the presence of strong
outflows. As a consequence, single-epoch virial black hole (BH) mass estimates
derived from CIV velocity-widths are known to be systematically biased compared
to masses from the hydrogen Balmer lines. Using a large sample of 230
high-luminosity (log $L_{\rm Bol}$ = 45.5-48 erg/s), redshift 1.5<z<4.0 quasars
with both CIV and Balmer line spectra, we have quantified the bias in CIV BH
masses as a function of the CIV blueshift. CIV BH masses are shown to be a
factor of five larger than the corresponding Balmer-line masses at CIV
blueshifts of 3000 km/s and are over-estimated by almost an order of magnitude
at the most extreme blueshifts, >5000 km/s. Using the monotonically increasing
relationship between the CIV blueshift and the mass ratio BH(CIV)/BH(H$\alpha$)
we derive an empirical correction to all CIV BH-masses. The scatter between the
corrected CIV masses and the Balmer masses is 0.24 dex at low CIV blueshifts
(~0 km/s) and just 0.10 dex at high blueshifts (~3000 km/s), compared to 0.40
dex before the correction. The correction depends only on the CIV line
properties - i.e. full-width at half maximum and blueshift - and can therefore
be applied to all quasars where CIV emission line properties have been
measured, enabling the derivation of un-biased virial BH mass estimates for the
majority of high-luminosity, high-redshift, spectroscopically confirmed quasars
in the literature.


title:
Reconciling threshold and subthreshold expansions for pion-nucleon
  scattering

abstract:
  Heavy-baryon chiral perturbation theory (ChPT) at one loop fails in relating
the pion-nucleon amplitude in the physical region and for subthreshold
kinematics due to loop effects enhanced by large low-energy constants. Studying
the chiral convergence of threshold and subthreshold parameters up to fourth
order in the small-scale expansion, we address the question to what extent this
tension can be mitigated by including the $\Delta(1232)$ as an explicit degree
of freedom and/or using a covariant formulation of baryon ChPT. We find that
the inclusion of the $\Delta$ indeed reduces the low-energy constants to more
natural values and thereby improves consistency between threshold and
subthreshold kinematics. In addition, even in the $\Delta$-less theory the
resummation of $1/m_N$ corrections in the covariant scheme improves the results
markedly over the heavy-baryon formulation, in line with previous observations
in the single-baryon sector of ChPT that so far have evaded a profound
theoretical explanation.


title:
The dust-to-stellar mass ratio as a valuable tool to probe the evolution
  of local and distant star forming galaxies

abstract:
  The survival of dust grains in galaxies depends on various processes. Dust
can be produced in stars, it can grow in the interstellar medium and be
destroyed by astration and interstellar shocks. In this paper, we assemble a
few data samples of local and distant star-forming galaxies to analyse various
dust-related quantities in low and high redshift galaxies, to study how the
relations linking the dust mass to the stellar mass and star formation rate
evolve with redshift. We interpret the available data by means of chemical
evolution models for discs and proto-spheroid (PSPH) starburst galaxies. In
particular, we focus on the dust-to-stellar mass (DTS) ratio, as this quantity
represents a true measure of how much dust per unit stellar mass survives the
various destruction processes in galaxies and is observable. The theoretical
models outline the strong dependence of this quantity on the underlying star
formation history. Spiral galaxies are characterised by a nearly constant DTS
as a function of the stellar mass and cosmic time, whereas PSPHs present an
early steep increase of the DTS, which stops at a maximal value and decreases
in the latest stages. In their late starburst phase, these models show a
decrease of the DTS with their mass, which allows us to explain the observed
anti-correlation between the DTS and the stellar mass. The observed redshift
evolution of the DTS ratio shows an increase from z~0 to z~1, followed by a
roughly constant behaviour at 1<z<2.5. Our models indicate a steep decrease of
the global DTS at early times, which implies an expected decrease of the DTS at
larger redshift.


title:
Ultra diffuse galaxies outside clusters: clues to their formation and
  evolution

abstract:
  We identify six ultra diffuse galaxies (UDGs) outside clusters in three
nearby isolated groups (z<0.026) using very deep imaging in three different
SDSS filters (g, r and i bands) from the IAC Stripe82 Legacy Project. By
comparing with the abundance of UDGs in rich galaxy clusters, we find that the
density of UDGs (i.e. their number per unit mass of the host structure where
they are located) decreases towards the most massive systems. This is
compatible with a scenario where UDGs are formed preferentially outside
clusters. In the periphery (D>250 kpc) of our three groups, we identify a
population of potential UDG progenitors (two of them confirmed
spectroscopically). These progenitors have similar masses, shapes and sizes but
are bluer, g-i~0.45, (and for this reason brighter, mu_g(0)<24 mag arcsec -2)
than traditional UDGs (g-i~0.76). A passive evolution of these progenitors will
transform them into regular (i.e. mu_g(0)>24 mag arcsec -2) UDGs after ~6 Gyr.
If confirmed, our observations support a scenario where UDGs are old, extended,
low surface brightness dwarfs (M*~10^8 Msun) galaxies born in the field, are
later on processed in groups and, ultimately, infall into galaxy clusters by
group accretion.


title: One Law To Rule Them All: The Radial Acceleration Relation of Galaxies

abstract:
  We study the link between baryons and dark matter in 240 galaxies with
spatially resolved kinematic data. Our sample spans 9 dex in stellar mass and
includes all morphological types. We consider (i) 153 late-type galaxies (LTGs;
spirals and irregulars) with gas rotation curves from the SPARC database; (ii)
25 early-type galaxies (ETGs; ellipticals and lenticulars) with stellar and HI
data from ATLAS^3D or X-ray data from Chandra; and (iii) 62 dwarf spheroidals
(dSphs) with individual-star spectroscopy. We find that LTGs, ETGs, and
"classical" dSphs follow the same radial acceleration relation: the observed
acceleration (gobs) correlates with that expected from the distribution of
baryons (gbar) over 4 dex. The relation coincides with the 1:1 line (no dark
matter) at high accelerations but systematically deviates from unity below a
critical scale of ~10^-10 m/s^2. The observed scatter is remarkably small
(<0.13 dex) and largely driven by observational uncertainties. The residuals do
not correlate with any global or local galaxy property (baryonic mass, gas
fraction, radius, etc.). The radial acceleration relation is tantamount to a
Natural Law: when the baryonic contribution is measured, the rotation curve
follows, and vice versa. Including ultrafaint dSphs, the relation may extend by
another 2 dex and possibly flatten at gbar<10^-12 m/s^2, but these data are
significantly more uncertain. The radial acceleration relation subsumes and
generalizes several well-known dynamical properties of galaxies, like the
Tully-Fisher and Faber-Jackson relations, the "baryon-halo" conspiracies, and
Renzo's rule.


title:
Thermally activated phase slips of one-dimensional Bose gases in shallow
  optical lattices

abstract:
  We study the decay of superflow via thermally activated phase slips in
one-dimensional Bose gases in a shallow optical lattice. By using the Kramers
formula, we numerically calculate the nucleation rate of a thermally activated
phase slip for various values of the filling factor and flow velocity in the
absence of a harmonic trapping potential. Within the local density
approximation, we derive a formula connecting the phase-slip nucleation rate
with the damping rate of a dipole oscillation of the Bose gas in the presence
of a harmonic trap. We use the derived formula to directly compare our theory
with the recent experiment done by the LENS group [L. Tanzi, et al., Sci. Rep.
{\bf 6}, 25965 (2016)]. From the comparison, the observed damping of dipole
oscillations in a weakly correlated and small velocity regime is attributed
dominantly to thermally activated phase slips rather than quantum phase slips.


title:
Z2Pack: Numerical Implementation of Hybrid Wannier Centers for
  Identifying Topological Materials

abstract:
  The intense theoretical and experimental interest in topological insulators
and semimetals has established band structure topology as a fundamental
material property. Consequently, identifying band topologies has become an
important, but often challenging problem, with no exhaustive solution at the
present time. In this work we compile a series of techniques, some previously
known, that allow for a solution to this problem for a large set of the
possible band topologies. The method is based on tracking hybrid Wannier charge
centers computed for relevant Bloch states, and it works at all levels of
materials modeling: continuous k.p models, tight-binding models and ab initio
calculations. We apply the method to compute and identify Chern, Z2 and
crystalline topological insulators, as well as topological semimetal phases,
using real material examples. Moreover, we provide a numerical implementation
of this technique (the Z2Pack software package) that is ideally suited for
high-throughput screening of materials databases for compounds with non-trivial
topologies. We expect that our work will allow researchers to: (a) identify
topological materials optimal for experimental probes, (b) classify existing
compounds and (c) reveal materials that host novel, not yet described,
topological states.


title:
Quantitative Evaluation of Gender Bias in Astronomical Publications from
  Citation Counts

abstract:
  We analyze the role of first (leading) author gender on the number of
citations that a paper receives, on the publishing frequency and on the
self-citing tendency. We consider a complete sample of over 200,000
publications from 1950 to 2015 from five major astronomy journals. We determine
the gender of the first author for over 70% of all publications. The fraction
of papers which have a female first author has increased from less than 5% in
the 1960s to about 25% today. We find that the increase of the fraction of
papers authored by females is slowest in the most prestigious journals such as
Science and Nature. Furthermore, female authors write 19$\pm$7% fewer papers in
seven years following their first paper than their male colleagues. At all
times papers with male first authors receive more citations than papers with
female first authors. This difference has been decreasing with time and amounts
to $\sim$6% measured over the last 30 years. To account for the fact that the
properties of female and male first author papers differ intrinsically, we use
a random forest algorithm to control for the non-gender specific properties of
these papers which include seniority of the first author, number of references,
total number of authors, year of publication, publication journal, field of
study and region of the first author's institution. We show that papers
authored by females receive 10.4$\pm$0.9% fewer citations than what would be
expected if the papers with the same non-gender specific properties were
written by the male authors. Finally, we also find that female authors in our
sample tend to self-cite more, but that this effect disappears when controlled
for non-gender specific variables.


title:
Automated Neutrino Jet and Top Jet Predictions at Next-to-Leading-Order
  with Parton Shower Matching in Effective Left-Right Symmetric Models

abstract:
  Hadronic decays of boosted resonances, e.g., top quark jets, at hadronic
super colliders are frequent predictions in TeV-scale extensions of the
Standard Model of Particle Physics. In such scenarios, accurate modeling of QCD
radiation is necessary for trustworthy predictions. We present the automation
of fully differential, next-to-leading-order (NLO) in QCD corrections with
parton shower (PS) matching for an effective Left-Right Symmetric Model (LRSM)
that features $W_R^\pm, Z_R$ gauge bosons and heavy Majorana neutrinos $N$.
Publicly available universal model files require remarkably fewer user inputs
for predicting benchmark collider processes than leading order LRSM
constructions. We present predictions for inclusive $W_R^\pm, Z_R$ production
at the $\sqrt{s} = 13$ TeV Large Hadron Collider (LHC) and a hypothetical
future 100 TeV Very Large Hadron Collider (VLHC), as well as inclusive $N$
production for a hypothetical Large Hadron Electron Collider (LHeC). As a case
study, we investigate at NLO+PS accuracy the properties of heavy neutrino
(color-singlet) jets and top quark (color-triplet) jets from decays of
high-mass $W_R$ bosons at the LHC. Contrary to top jets, we find that the
kinematic properties of heavy neutrinos jets, and in particular jet mass, are
resilient against the effects of parton showers and hard QCD radiation. This
suggests that in searches for neutrino jets, aggressive selection cuts that
would otherwise be inappropriate for top jets can be imposed with minimal
signal loss.


title:
Chiral magnetic effect without chirality source in asymmetric Weyl
  semimetals

abstract:
  We describe a new type of the Chiral Magnetic Effect (CME) that should occur
in Weyl semimetals with an asymmetry in the dispersion relations of the left-
and right-handed chiral Weyl fermions. In such materials, time-dependent
pumping of electrons from a non-chiral external source generates a
non-vanishing chiral chemical potential. This is due to the different
capacities of the left- and right-handed (LH and RH) chiral Weyl cones arising
from the difference in the density of states in the LH and RH cones. The chiral
chemical potential then generates, via the chiral anomaly, a current along the
direction of an applied magnetic field even in the absence of an external
electric field. The source of chirality imbalance in this new setup is thus due
to the band structure of the system and the presence of (non-chiral) electron
source, and not due to the parallel electric and magnetic fields. We illustrate
the effect by an argument based on the effective field theory, and by the
chiral kinetic theory calculation for a rotationally invariant Weyl semimetal
with different Fermi velocities in the left and right chiral Weyl cones; we
also consider the case of a Weyl semimetal with Weyl nodes at different
energies. We argue that this effect is generically present in Weyl semimetals
with different dispersion relations for LH and RH chiral Weyl cones, such as
SrSi2 recently predicted as a Weyl semimetal with broken inversion and mirror
symmetries, as long as the chiral relaxation time is much longer than the
transport scattering time.


title: Holographic Isotropisation in Gauss-Bonnet Gravity

abstract:
  We study holographic isotropisation of homogeneous, strongly coupled,
non-Abelian plasmas in Gauss-Bonnet gravity with a negative cosmological
constant. We focus on small values of the Gauss-Bonnet coupling parameter
$\lambda_{GB}$ and linearise the equations of motion around a time-dependent
background solution with $\lambda_{GB}=0$. We numerically solve the linearised
equations and show that the entire time evolution of the pressure anisotropy
can be well approximated by the linear in $\lambda_{GB}$ corrections to the
quasinormal mode expansion, even in the cases of high anisotropy. We finally
show that, quite generally, the time evolution of the pressure anisotropy with
the Gauss-Bonnet term is approximately {\it shifted} with respect to the
evolution without it, with the sign of the shift being directly related to the
sign of the $\lambda_{GB}$ parameter. This suggests that finite coupling
corrections generically {\it increase} the isotropisation time of strongly
coupled plasmas.


title: Raise and collapse of strain-induced pseudo-Landau levels in graphene

abstract:
  Lattice deformations couple to the low energy electronic excitations of
graphene as vector fields similar to the electromagnetic potential
\cite{SA02b,VKG10}. The suggestion that certain strain configurations would be
able to induce pseudo landau levels in the spectrum of graphene
\cite{GKG10,GGKN10}, and the subsequent experimental observation of these
\cite{LBetal10} has been one of the most exciting events in an already
fascinating field. It opened a new field of research "straintronics" linked to
new applications, and had a strong influence on the physics of the new Dirac
materials in two and three dimensions \cite{Amorim16}. The experimental
observation of pseudo landau levels with scanning tunnel microscopy presents
nevertheless some ambiguities. Similar strain patterns show different images
sometimes difficult to interpret. In this work we strain the analogy of the
pseudo versus real electromagnetic fields, as well as the fact that graphene
has a relativistic behavior and show that, for some strain configurations, the
deformation potential acts like a parallel electric field able to destabilize
the Landau level structure via a mechanism identical to that described in
\cite{LSB07,PC07} for real electromagnetic fields. The underlying physics is
the combination of Maxwell electrodynamics and special relativity implying that
different reference frames observe different electromagnetic fields
\cite{LSB07}. The mechanism applies equally if the electric field has an
external origin, which opens the door to an electric control of the giant
pseudomagnetic fields in graphene.


title:
Measurement of the $D^+$-meson production cross section at low
  transverse momentum in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

abstract:
  We report on a measurement of the $D^{+}$-meson production cross section as a
function of transverse momentum ($p_T$) in proton-antiproton ($p\bar{p}$)
collisions at 1.96 TeV center-of-mass energy, using the full data set collected
by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10
fb$^{-1}$ of integrated luminosity. We use $D^{+} \to K^-\pi^+\pi^+$ decays
fully reconstructed in the central rapidity region $|y|<1$ with transverse
momentum down to 1.5 GeV/$c$, a range previously unexplored in $p\bar{p}$
collisions. Inelastic $p\bar{p}$-scattering events are selected online using
minimally-biasing requirements followed by an optimized offline selection. The
$K^-\pi^+\pi^+$ mass distribution is used to identify the $D^+$ signal, and the
$D^+$ transverse impact-parameter distribution is used to separate prompt
production, occurring directly in the hard scattering process, from secondary
production from $b$-hadron decays. We obtain a prompt $D^+$ signal of 2950
candidates corresponding to a total cross section $\sigma(D^+, 1.5 < p_T <
14.5~\mbox{GeV/}c, |y|<1) = 71.9 \pm 6.8 (\mbox{stat}) \pm 9.3
(\mbox{syst})~\mu$b. While the measured cross sections are consistent with
theoretical estimates in each $p_T$ bin, the shape of the observed $p_T$
spectrum is softer than the expectation from quantum chromodynamics. The
results are unique in $p\bar{p}$ collisions and can improve the shape and
uncertainties of future predictions.


title:
A Young Eclipsing Binary and its Luminous Neighbors in the Embedded Star
  Cluster Sh 2-252E

abstract:
  We present a photometric and light curve analysis of an eccentric eclipsing
binary in the K2 Campaign 0 field that resides in Sh 2-252E, a young star
cluster embedded in an H II region. We describe a spectroscopic investigation
of the three brightest stars in the crowded aperture to identify which is the
binary system. We find that none of these stars are components of the eclipsing
binary system, which must be one of the fainter nearby stars. These bright
cluster members all have remarkable spectra: Sh 2-252a (EPIC 202062176) is a
B0.5 V star with razor sharp absorption lines, Sh 2-252b is a Herbig A0 star
with disk-like emission lines, and Sh 2-252c is a pre-main sequence star with
very red color.


title:
Mechanical, elastic and thermodynamic properties of crystalline lithium
  silicides

abstract:
  We investigate crystalline thermodynamic stable lithium silicides phases
(LixSiy) with density functional theory (DFT) and a force-field method based on
modified embedded atoms (MEAM) and compare our results with experimental data.
This work presents a fast and accurate framework to calculate thermodynamic
properties of crystal structures with large unit cells with MEAM based on
molecular dynamics (MD). Mechanical properties like the bulk modulus and the
elastic constants are evaluated in addition to thermodynamic properties
including the phonon density of states, the vibrational free energy and the
isochoric/isobaric specific heat capacity for Li, Li12Si7, Li7Si3, Li13Si4,
Li15Si4, Li21Si5, Li17Si4, Li22Si5 and Si. For a selected phase (Li13Si4) we
study the effect of a temperature dependent phonon density of states and its
effect on the isobaric heat capacity.


title:
Quantum Monte Carlo study of the energetics of the rutile, anatase,
  brookite, and columbite TiO$_2$ polymorphs

abstract:
  The relative energies of the low-pressure rutile, anatase, and brookite
polymorphs and the high-pressure columbite polymorph of TiO$_2$ have been
calculated as a function of temperature using the diffusion quantum Monte Carlo
(DMC) method and density functional theory (DFT). The vibrational energies are
found to be important on the scale of interest and significant quartic
anharmonicity is found in the rutile phase. Static-lattice DFT calculations
predict that anatase is lower in energy than rutile, in disagreement with
experiment. The accurate description of electronic correlations afforded by DMC
calculations and the inclusion of anharmonic vibrational effects contribute to
stabilizing rutile with respect to anatase. Our calculations predict a phase
transition from anatase to rutile TiO$_2$ at $630 \pm 210$ K.


title: The Ergodic Side of the Many-Body Localization Transition

abstract:
  Recent studies point towards nontriviality of the ergodic phase in systems
exhibiting many-body localization (MBL), which shows subexponential relaxation
of local observables, subdiffusive transport and sublinear spreading of the
entanglement entropy. Here we review the dynamical properties of this phase and
the available numerically exact and approximate methods for its study. We
discuss in which sense this phase could be considered ergodic and present
possible phenomenological explanations of its dynamical properties. We close by
analyzing to which extent the proposed explanations were verified by numerical
studies and present the open questions in this field.


title: On self-similarity of wreath products of abelian groups

abstract:
  We prove that a self-similar free abelian group has finite rank. We apply the
result to self-similar wreath products of abelian groups $G=BwrX$. We show that
if $X$ is torsion-free, then $B$ is torsion of finite exponent. Furthemore, we
construct a self-similar group $G=BwrC_{2}$ where $B$ is free abelian of
infinite rank.


title: The accretion rate dependence of burst oscillation amplitude

abstract:
  Neutron stars in low mass X-ray binaries exhibit oscillations during
thermonuclear bursts, attributed to asymmetric brightness patterns on the
burning surfaces. All models that have been proposed to explain the origin of
these asymmetries (spreading hotspots, surface waves, and cooling wakes) depend
on the accretion rate. By analysis of archival RXTE data of six oscillation
sources, we investigate the accretion rate dependence of the amplitude of burst
oscillations. This more than doubles the size of the sample analysed previously
by Muno et al. (2004), who found indications for a relationship between
accretion rate and oscillation amplitudes. We find that burst oscillation
signals can be detected at all observed accretion rates. Moreover, oscillations
at low accretion rates are found to have relatively small amplitudes
($A_\text{rms}\leq0.10$) while oscillations detected in bursts observed at high
accretion rates cover a broad spread in amplitudes ($0.05\leq
A_\text{rms}\leq0.20$). In this paper we present the results of our analysis
and discuss these in the light of current burst oscillation models.
Additionally, we investigate the bursts of two sources without previously
detected oscillations. Despite that these sources have been observed at
accretion rates where burst oscillations might be expected, we find their
behaviour to be not anomalous compared to oscillation sources.


title: On cardinality bounds involving the weak Lindel\"of degree

abstract:
  We give a general closing-off argument in Theorem 2.1 from which several
corollaries follow, including (1) if $X$ is a locally compact Hausdorff space
then $|X|\leq 2^{wL(X)\psi(X)}$, and (2) if $X$ is a locally compact power
homogeneous Hausdorff space then $|X|\leq 2^{wL(X)t(X)}$. The first extends the
well-known cardinality bound $2^{\psi(X)}$ for a compactum $X$ in a new
direction. As $|X|\leq 2^{wL(X)\chi(X)}$ for a normal space $X$ [3], this
enlarges the class of known Tychonoff spaces for which this bound holds. In
2.10 we give a short, direct proof of (1) that does not use 2.1. Yet 2.1 is
broad enough to establish results much more general than (1), such as if $X$ is
a regular space with a $\pi$-base $\scr{B}$ such that $|B|\leq
2^{wL(X)\chi(X)}$ for all $B\in\scr{B}$, then $|X|\leq 2^{wL(X)\chi(X)}$.
  Separately, it is shown that if $X$ is a regular space with a $\pi$-base
whose elements have compact closure, then $|X|\leq 2^{wL(X)\psi(X)t(X)}$. This
partially answers a question from [3] and gives a third, separate proof of (1).
We also show that if $X$ is a weakly Lindel\"of, normal, sequential space with
$\chi(X)\leq 2^{\aleph_0}$, then $|X|\leq 2^{\aleph_0}$.
  Result (2) above is a new generalization of the cardinality bound $2^{t(X)}$
for a power homogeneous compactum $X$ (Arhangel'skii, van Mill, and Ridderbos
[2], De la Vega in the homogeneous case [9]). To this end we show that if
$U\subseteq clD\subseteq X$, where $X$ is power homogeneous and $U$ is open,
then $|U|\leq |D|^{\pi_{\chi}(X)}$. This is a strengthening of a result of
Ridderbos [18].


title: IC 3639 - A new bona fide Compton thick AGN unveiled by NuSTAR

abstract:
  We analyse high-quality NuSTAR observations of the local (z = 0.011) Seyfert
2 active galactic nucleus (AGN) IC 3639, in conjunction with archival Suzaku
and Chandra data. This provides the first broadband X-ray spectral analysis of
the source, spanning nearly two decades in energy (0.5-30 keV). Previous X-ray
observations of the source below 10 keV indicated strong reflection/obscuration
on the basis of a pronounced iron fluorescence line at 6.4 keV. The hard X-ray
energy coverage of NuSTAR, together with self-consistent toroidal reprocessing
models, enables direct broadband constraints on the obscuring column density of
the source. We find the source to be heavily Compton-thick (CTK) with an
obscuring column in excess of $3.6\times10^{24}$ cm$^{-2}$, unconstrained at
the upper end. We further find an intrinsic 2-10 keV luminosity of
$\textrm{log}_{10}(L_{\textrm{2-10 keV}} \textrm{[erg s}^{-1}]) =
43.4^{+0.6}_{-1.1}$ to 90% confidence, almost 400 times the observed flux, and
consistent with various multi-wavelength diagnostics. Such a high intrinsic to
observed flux ratio in addition to an Fe-K$\alpha$ fluorescence line equivalent
width exceeding 2 keV is extreme amongst known bona fide CTK AGN, which we
suggest are both due to the high level of obscuration present around IC 3639.
Our study demonstrates that broadband spectroscopic modelling with NuSTAR
enables large corrections for obscuration to be carried out robustly, and
emphasises the need for improved modelling of AGN tori showing intense iron
fluorescence.


title:
Giant modulation of the electronic band gap of carbon nanotubes by
  dielectric screening

abstract:
  Carbon nanotubes (CNTs) are a promising material for high-performance
electronics beyond silicon. But unlike silicon, the nature of the transport
band gap in CNTs is not fully understood. The transport gap in CNTs is
predicted to be strongly driven by electron-electron (e-e) interactions and
correlations, even at room temperature. Here, we use dielectric liquids to
screen e-e interactions in individual suspended ultra-clean CNTs. Using
multiple techniques, the transport gap is measured as dielectric screening is
increased. Changing the dielectric environment from air to isopropanol, we
observe a 25% reduction in the transport gap of semiconducting CNTs, and a 32%
reduction in the band gap of narrow-gap CNTs. Additional measurements are
reported in dielectric oils. Our results elucidate the nature of the transport
gap in CNTs, and show that dielectric environment offers a mechanism for
significant control over the transport band gap.


title: Vortices with source, FQHE and nontrivial statistics in 2+1 dimensions

abstract:
  We investigate vortex soliton solutions in 2+1 dimensional scalar gauge
theories, in the presence of source terms in the action. Concretely, this would
be applied to anyons, as well as the Fractional Quantum Hall Effect (FQHE). We
classify solitons for renormalizable potentials, as well as some
nonrenormalizable examples that could be relevant for the FQHE. The non-Abelian
case, specifically for theories with global non-Abelian symmetries, is also
investigated, as is the non-relativistic limit of the above theories, when we
get a modification of the Jackiw-Pi model, with an interesting new vortex
solution. We explore the application to the ABJM model, as well as more general
SYM-CS models in 2+1 dimensions.


title: Long-range exchange interaction between magnetic impurities in graphene

abstract:
  The effective spin exchange coupling between impurities (adatoms) on graphene
mediated by conduction electrons is studied as a function of the strength of
the potential part of the on-site energy $U$ of the electron-adatom
interaction. With increasing $U$, the exchange coupling becomes long-range,
determined largely by the impurity levels with energies close to the Dirac
points. When adatoms reside on opposite sublattices, their exchange coupling,
normally antiferromagnetic, becomes ferromagnetic and resonantly enhanced at a
specific distance where an impurity level crosses the Dirac point.


title: SoundNet: Learning Sound Representations from Unlabeled Video

abstract:
  We learn rich natural sound representations by capitalizing on large amounts
of unlabeled sound data collected in the wild. We leverage the natural
synchronization between vision and sound to learn an acoustic representation
using two-million unlabeled videos. Unlabeled video has the advantage that it
can be economically acquired at massive scales, yet contains useful signals
about natural sound. We propose a student-teacher training procedure which
transfers discriminative visual knowledge from well established visual
recognition models into the sound modality using unlabeled video as a bridge.
Our sound representation yields significant performance improvements over the
state-of-the-art results on standard benchmarks for acoustic scene/object
classification. Visualizations suggest some high-level semantics automatically
emerge in the sound network, even though it is trained without ground truth
labels.


title:
The Effect of Pets on Happiness: A Data-Driven Approach via Large-Scale
  Social Media

abstract:
  Psychologists have demonstrated that pets have a positive impact on owners'
happiness. For example, lonely people are often advised to have a dog or cat to
quell their social isolation. Conventional psychological research methods of
analyzing this phenomenon are mostly based on surveys or self-reported
questionnaires, which are time-consuming and lack of scalability. Utilizing
social media as an alternative and complimentary resource could potentially
address both issues and provide different perspectives on this psychological
investigation. In this paper, we propose a novel and effective approach that
exploits social media to study the effect of pets on owners' happiness. The
proposed framework includes three major components: 1) collecting user-level
data from Instagram consisting of about 300,000 images from 2905 users; 2)
constructing a convolutional neural network (CNN) for pets classification, and
combined with timeline information, further identifying pet owners and the
control group; 3) measuring the confidence score of happiness by detecting and
analyzing selfie images. Furthermore, various factors of demographics are
employed to analyze the fine-grained effects of pets on happiness. Our
experimental results demonstrate the effectiveness of the proposed approach and
we believe that this approach can be applied to other related domains as a
large-scale, high-confidence methodology of user activity analysis through
social media.


title: Cross-Modal Scene Networks

abstract:
  People can recognize scenes across many different modalities beyond natural
images. In this paper, we investigate how to learn cross-modal scene
representations that transfer across modalities. To study this problem, we
introduce a new cross-modal scene dataset. While convolutional neural networks
can categorize scenes well, they also learn an intermediate representation not
aligned across modalities, which is undesirable for cross-modal transfer
applications. We present methods to regularize cross-modal convolutional neural
networks so that they have a shared representation that is agnostic of the
modality. Our experiments suggest that our scene representation can help
transfer representations across modalities for retrieval. Moreover, our
visualizations suggest that units emerge in the shared representation that tend
to activate on consistent concepts independently of the modality.


title:
Ricci flow, Courant algebroids, and renormalization of Poisson--Lie
  T-duality

abstract:
  We use a generalized Ricci tensor, defined for generalized metrics in Courant
algebroids, to show that Poisson-Lie T-duality is compatible with the 1-loop
renormalization group.


title: Fast and Consistent Algorithm for the Latent Block Model

abstract:
  In this paper, the algorithm $Largest$ $Gaps$ is introduced, for
simultaneously clustering both rows and columns of a matrix to form homogeneous
blocks. The definition of clustering is model-based: clusters and data are
generated under the Latent Block Model. In comparison with algorithms designed
for this model, the major advantage of the $Largest$ $Gaps$ algorithm is to
cluster using only some marginals of the matrix, the size of which is much
smaller than the whole matrix. The procedure is linear with respect to the
number of entries and thus much faster than the classical algorithms. It
simultaneously selects the number of classes as well, and the estimation of the
parameters is then made very easily once the classification is obtained.
Moreover, the paper proves the procedure to be consistent under the LBM, and it
illustrates the statistical performance with some numerical experiments.


title: On the Semi-Classical Limit of Scalar Products of the XXZ Spin Chain

abstract:
  We study the scalar products between Bethe states in the XXZ spin chain with
anisotropy $|\Delta|>1$ in the semi-classical limit where the length of the
spin chain and the number of magnons tend to infinity with their ratio kept
finite and fixed. Our method is a natural yet non-trivial generalization of
similar methods developed for the XXX spin chain. The final result can be
written in a compact form as a contour integral in terms of Faddeev's quantum
dilogarithm function, which in the isotropic limit reduces to the classical
dilogarithm function.

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


title:
Magnetic activity in the HARPS M-dwarf sample. The rotation-activity
  relationship for very low-mass stars through R'HK

abstract:
  Atmospheric magnetic fields in stars with convective envelopes heat stellar
chromospheres. Starting with the historical Mount Wilson monitoring program,
CaH&K lines have been widely used to trace stellar magnetic activity, and as a
proxy for rotation period and consequently for stellar age. Monitoring stellar
activity has also become essential in filtering out false-positives due to
magnetic activity in extra-solar planet surveys. The Ca H&Kemission is
traditionally quantified through the R'HK-index, which compares the
chromospheric flux in the doublet to the overall bolometric flux of the star.
Much work has been done to characterize this index for FGK-dwarfs, but M-dwarfs
were left out of these analyses and no calibration of their Ca ii H&K emission
to an R'HK exists to date. We set out to characterize the magnetic activity of
the low and very low-mass stars by providing a calibration of the R'HK-index
that extends to the realm of M-dwarfs, and by evaluating the relation between
R'HK and the rotation period. We calibrated the bolometric and photospheric
factors for M-dwarfs to properly transform the S-index into the R'HK. We
monitored magnetic activity through the Ca ii H&K emission lines in the HARPS
M-dwarf sample. The R'HK index, like the fractional X-ray luminosity L_X/Lbol,
shows a saturated correlation with rotation, with saturation setting in around
a ten days rotation period. Above that period, slower rotators show weaker Ca
ii activity, as expected. Under that period, the R'HK index saturates to
~10^-4. Stellar mass modulates the Ca ii activity, with R'HK showing a constant
basal activity above 0.6Msun and then decreasing with mass between 0.6Msun and
the fully-convective limit of 0.35Msun. Short-term variability of the activity
correlates with its mean level, stars with higher R'HK index show larger R'HK
variability, as previously observed for earlier spectral types.


title:
Pressure-dependent water absorption cross sections for exoplanets and
  other atmospheres

abstract:
  Many atmospheres (cool stars, brown dwarfs, giant planets, extrasolar
planets) are predominately composed of molecular hydrogen and helium.
H$_2{}^{16}$O is one of the best measured molecules in extrasolar planetary
atmospheres to date and a major compound in the atmospheres of brown-dwarfs and
oxygen-rich cool stars, yet the scope of experimental and theoretical studies
on the pressure broadening of water vapour lines by collision with hydrogen and
helium remains limited.
  Theoretical H$_2$- and He-broadening parameters of water vapour lines
(rotational quantum number $J$ up to 50) are obtained for temperatures in the
range 300 - 2000 K. Two approaches for calculation of line widths were used:
(i) the averaged energy difference method and (ii) the empirical expression for
$J$\p $J$\pp-dependence.
  Voigt profiles based on these widths and the BT2 line list are used to
generate high resolution ($\Delta \tilde{\nu}$ = 0.01 \cm) pressure broadened
cross sections for a fixed range of temperatures and pressures between 300 -
2000 K and 0.001 - 10 bar. An interpolation procedure which can be used to
determine cross sections at intermediate temperature and pressure is described.
Pressure broadening parameters and cross sections are presented in new ExoMol
format.


title:
The cellular second fundamental theorem of invariant theory for
  classical groups

abstract:
  We prove that the centralizer algebras of the symplectic and orthogonal group
acting on tensor space are cellular algebras over the integers. We do this by
providing an axiomatic framework for studying quotient towers for towers of
diagram algebras. Our framework covers the centralizer algebras of the general
linear group acting on mixed tensor space as well. We also provide descriptions
of the kernels of the homomorphisms from the diagrammatic versions of the
algebras to the centralizer algebras on tensor space, which constitute versions
of the second fundamental theorem of invariant theory.


title: Diagram algebras, dominance triangularity, and skew cell modules

abstract:
  We present an abstract framework for the axiomatic study of diagram algebras.
Algebras that fit this framework possess analogues of both the Murphy and
seminormal bases of the Hecke algebras of the symmetric groups. We show that
the transition matrix between these bases is dominance unitriangular. We
construct analogues of the skew Specht modules in this setting. This allows us
to propose a natural tableaux theoretic framework in which to study the
infamous Kronecker problem.


title: Anchor Free IP Mobility

abstract:
  Efficient mobility management techniques are critical in providing seamless
connectivity and session continuity between a mobile node and the network
during its movement. Current mobility management solutions generally require a
central entity in the network core, tracking IP address movement and anchoring
traffic from source to destination through point-to-point tunnels. Intuitively,
this approach suffers from scalability limitations as it creates bottlenecks in
the network, due to sub-optimal routing via the anchor point. Meanwhile,
alternative anchorless, solutions are not feasible due to the current
limitations of the IP semantics, which strongly ties addressing information to
location. In contrast, novel path-based forwarding solutions may be exploited
for feasible anchorless solutions. In this paper, we propose a novel
network-based mobility management solution that facilitates IP mobility over
such a path-based forwarding substrate. Our solution exploits the advantages of
such substrates in decoupling path calculation from data transfer to eliminate
the need for anchoring traffic through the network core; thereby, allowing
flexible path calculation and service provisioning. Furthermore, by eliminating
the limitation of routing via the anchor point, our approach reduces the
network cost compared to anchored solution through bandwidth saving while
maintaining comparable handover delay. We evaluate our solution through
analytical and simulation models and compare it with the IETF standardized
solution, Proxy Mobile IPv6 (PMIPv6). Evaluation results illustrate a
significant saving in the total network cost when using our proposed solution,
compared to its counterpart.


title: Empirical Evaluation of Effort on Composing Design Models

abstract:
  Model composition plays a central role in many software engineering
activities such as evolving models to add new features and reconciling
conflicting design models developed in parallel by different development teams.
As model composition is usually an error-prone and effort-consuming task, its
potential benefits, such as gains in productivity can be compromised. However,
there is no empirical knowledge nowadays about the effort required to compose
design models. Only feedbacks of model composition evangelists are available,
and they often diverge. Consequently, developers are unable to conduct any
cost-effectiveness analysis as well as identify, predict, or reduce composition
effort. The inability of evaluating composition effort is due to three key
problems. First, the current evaluation frameworks do not consider fundamental
concepts in model composition such as conflicts and inconsistencies. Second,
researchers and developers do not know what factors can influence the
composition effort in practice. Third, practical knowledge about how such
influential factors may affect the developers' effort is severely lacking. In
this context, the contributions of this thesis are threefold: (i) a quality
model for supporting the evaluation of model composition effort, (ii) practical
knowledge, derived from a family of quantitative and qualitative empirical
studies, about model composition effort and its influential factors, and (iii)
insight about how to evaluate model composition efforts and tame the side
effects of such influential factors.


title: Compressive Holographic Video

abstract:
  Compressed sensing has been discussed separately in spatial and temporal
domains. Compressive holography has been introduced as a method that allows 3D
tomographic reconstruction at different depths from a single 2D image. Coded
exposure is a temporal compressed sensing method for high speed video
acquisition. In this work, we combine compressive holography and coded exposure
techniques and extend the discussion to 4D reconstruction in space and time
from one coded captured image. In our prototype, digital in-line holography was
used for imaging macroscopic, fast moving objects. The pixel-wise temporal
modulation was implemented by a digital micromirror device. In this paper we
demonstrate $10\times$ temporal super resolution with multiple depths recovery
from a single image. Two examples are presented for the purpose of recording
subtle vibrations and tracking small particles within 5 ms.


title:
The Case for a Publicly Available, Well-Instrumented GBT Operating at
  20-115 GHz

abstract:
  A well-instrumented Green Bank Telescope (GBT) operating at high frequency
represents a unique scientific resource for the US community. As a
filled-aperture, 100m-diameter telescope, the GBT is ideally suited to fast
mapping of extended, low surface brightness emission with excellent
instantaneous frequency coverage. This capability makes the GBT a key facility
for a range of cutting edge science described in this document, only possible
at these frequencies. We note that the ability to perform the necessary
observations is unique and highly complementary to the capabilities offered by
interferometers, and should be preserved. We argue that rather than divesting
from this exceptional resource, it makes sense for the US community to invest
moderately to maintain GBT operations and to instrument it in an optimal
manner, enabling it to become an extraordinary complement to existing and
future radio interferometers. Adequately instrumented, the GBT would be a
pillar for 20-115 GHz science in the US and the world.


title:
Exponential parameterization of the neutrino mixing matrix - comparative
  analysis with different data sets and CP violation

abstract:
  The exponential parameterization of Pontecorvo-Maki-Nakagawa-Sakata mixing
matrix for neutrino is used for comparative analysis of different neutrino
mixing data. The UPMNS matrix is considered as the element of the SU(3) group
and the second order matrix polynomial is constructed for it. The inverse
problem of constructing the logarithm of the mixing matrix is addressed. In
this way the standard parameterization is related to the exponential
parameterization exactly. The exponential form allows easy factorization and
separate analysis of the rotation and the CP violation. With the most recent
experimental data on the neutrino mixing (May 2016), we calculate the values of
the exponential parameterization matrix for neutrinos with account for the CP
violation. The complementarity hypothesis for quarks and neutrinos is
demonstrated to hold, despite significant change in the neutrino mixing data.
The values of the entries of the exponential mixing matrix are evaluated with
account for the actual degree of the CP violation in neutrino mixing and
without it. Various factorizations of the CP violating term are investigated in
the framework of the exponential parameterization.


title: On the weighted Gau{\ss}--Radau Quadrature

abstract:
  In this short note, we collect some facts on the weighted Gau{\ss}--Radau
quadrature. In particular, we focus on the location of the Gau\ss--Radau points
being a continuous function of the $L^1$-weighting function.


title: Applications of Jarzynski's relation in lattice gauge theories

abstract:
  Jarzynski's equality is a well-known result in statistical mechanics,
relating free-energy differences between equilibrium ensembles with
fluctuations in the work performed during non-equilibrium transformations from
one ensemble to the other. In this work, an extension of this relation to
lattice gauge theory will be presented, along with numerical results for the
$\mathbb{Z}_2$ gauge model in three dimensions and for the equation of state in
$\mathrm{SU}(2)$ Yang-Mills theory in four dimensions. Then, further
applications will be discussed, in particular for the Schr\"odinger functional
and for the study of QCD in strong magnetic fields.


title: Optimal Belief Approximation

abstract:
  In Bayesian statistics probability distributions express beliefs. However,
for many problems the beliefs cannot be computed analytically and
approximations of beliefs are needed. We seek a loss function that quantifies
how "embarrassing" it is to communicate a given approximation. We reproduce and
discuss an old proof showing that there is only one ranking under the
requirements that (1) the best ranked approximation is the non-approximated
belief and (2) that the ranking judges approximations only by their predictions
for actual outcomes. The loss function that is obtained in the derivation is
equal to the Kullback-Leibler divergence when normalized. This loss function is
frequently used in the literature. However, there seems to be confusion about
the correct order in which its functional arguments, the approximated and
non-approximated beliefs, should be used. The correct order ensures that the
recipient of a communication is only deprived of the minimal amount of
information. We hope that the elementary derivation settles the apparent
confusion. For example when approximating beliefs with Gaussian distributions
the optimal approximation is given by moment matching. This is in contrast to
many suggested computational schemes.


title: Crystallographic Multiwavelets in $L^2(R^d)$

abstract:
  We characterize the scaling function of a crystal Multiresolution Analysis in
terms of the vector-scaling function for a Multiresolution Analysis associated
to a lattice. We give necessary and sufficient conditions in terms of the
symbol matrix in order that an associated crystal wavelet basis exists.


title:
Dealing with bad apples: Robust range-based network localization via
  distributed relaxation methods

abstract:
  Real-world network applications must cope with failing nodes, malicious
attacks, or, somehow, nodes facing corrupted data --- classified as outliers.
One enabling application is the geographic localization of the network nodes.
However, despite excellent work on the network localization problem, prior
research seldom considered outlier data --- even now, when already deployed
networks cry out for robust procedures. We propose robust, fast, and
distributed network localization algorithms, resilient to high-power noise, but
also precise under regular Gaussian noise. We use the Huber M-estimator as a
difference measure between the distance of estimated nodes and noisy range
measurements, thus obtaining a robust (but nonconvex) optimization problem. We
then devise a convex underestimator solvable in polynomial time, and tight in
the inter-node terms. We also provide an optimality bound for the convex
underestimator. We put forward a new representation of the Huber function
composed with a norm, enabling distributed robust localization algorithms to
minimize the proposed underestimator. The synchronous distributed method has
optimal convergence rate and the asynchronous one converges in finite time, for
a given precision. The main highlight of our contribution lies on the fact that
we pay no price for distributed computation nor in accuracy, nor in
communication cost or convergence speed. Simulations show the advantage of
using our proposed algorithms, both in the presence of outliers and under
regular Gaussian noise: our method exceeds the accuracy of an alternative
robust approach based on L1 norms by at least 100m in an area of 1Km sides.


title:
Dirac Fermions induced in strained zigzag phosphorus nanotubes and the
  applications in field effect transistors

abstract:
  In this work, Dirac fermions have been obtained and engineered in
one-dimensional (1D) zigzag phosphorus nanotubes (ZPNTs). We have performed a
comprehensive first-principle computational study of the electronic properties
of ZPNTs with various diameters. The results indicate that as the lattice
parameter (Lc) along axial direction increases, ZPNTs undergo transitions from
metal to semimetal and semimetal to semiconductor, whereas Dirac fermions
appear at Lc ranging from 3.90{\AA} to 4.10{\AA}. In particular, a field effect
transistor (FET) based on a 12-ZPNT (with 12 unit cells in transverse
direction) exhibits semiconductor behaviors with efficient gate-effect
modulation at Lc= 4.60{\AA}. However, only weak gate modulation is demonstrated
when the nanotube becomes semimetal at Lc= 4.10{\AA}. This study indicates that
ZPNTs are profoundly appealing in applications in the strain sensors. Our
findings pave the way for development of high-performance strain-engineered
electronics based on Dirac Fermions in 1D materials.


title: Long-term data storage in diamond

abstract:
  The negatively-charged nitrogen-vacancy (NV-) center in diamond is the focus
of widespread attention for applications ranging from quantum information
processing to nanoscale metrology. Although most work so far has focused on the
NV- optical and spin properties, control of the charge state promises
complementary opportunities. One intriguing possibility is the long-term
storage of information, a notion we hereby introduce using NV rich, type-1b
diamond. As a proof of principle, we use multi-color optical microscopy to
read, write, and reset arbitrary data sets with 2-D binary bit density
comparable to present digital-video-disk (DVD) technology. Leveraging on the
singular dynamics of NV- ionization, we encode information on different planes
of the diamond crystal with no cross talk, hence extending the storage capacity
to three dimensions. Further, we correlate the center's charge state and
nuclear spin polarization of the nitrogen host, and show that the latter is
robust to a cycle of NV- ionization and recharge. In combination with
super-resolution microscopy techniques, these observations provide a route
towards sub-diffraction NV charge control, a regime where the storage capacity
could exceed present technologies.


title:
A Simple and Accurate Network for Hydrogen and Carbon Chemistry in the
  ISM

abstract:
  Chemistry plays an important role in the interstellar medium (ISM),
regulating heating and cooling of the gas, and determining abundances of
molecular species that trace gas properties in observations. Although solving
the time-dependent equations is necessary for accurate abundances and
temperature in the dynamic ISM, a full chemical network is too computationally
expensive to incorporate in numerical simulations. In this paper, we propose a
new simplified chemical network for hydrogen and carbon chemistry in the atomic
and molecular ISM. We compare results from our chemical network in detail with
results from a full photo-dissociation region (PDR) code, and also with the
Nelson & Langer (1999) (NL99) network previously adopted in the simulation
literature. We show that our chemical network gives similar results to the PDR
code in the equilibrium abundances of all species over a wide range of
densities, temperature, and metallicities, whereas the NL99 network shows
significant disagreement. Applying our network in 1D models, we find that the
$\mathrm{CO}$-dominated regime delimits the coldest gas and that the
corresponding temperature tracks the cosmic ray ionization rate in molecular
clouds. We provide a simple fit for the locus of $\mathrm{CO}$ dominated
regions as a function of gas density and column. We also compare with
observations of diffuse and translucent clouds. We find that the $\mathrm{CO}$,
$\mathrm{CHx}$ and $\mathrm{OHx}$ abundances are consistent with equilibrium
predictions for densities $n=100-1000~\mathrm{cm^{-3}}$, but the predicted
equilibrium $\mathrm{C}$ abundance is higher than observations, signaling the
potential importance of non-equilibrium/dynamical effects.


title: Flavored Gauge Mediation with Discrete Non-Abelian Symmetries

abstract:
  We explore the model-building and phenomenology of flavored gauge mediation
models of supersymmetry breaking in which the electroweak Higgs doublets and
the SU(2) messenger doublets are connected by a discrete non-Abelian symmetry.
The embedding of the Higgs and messenger fields into representations of this
non-Abelian Higgs-messenger symmetry results in specific relations between the
Standard Model Yukawa couplings and the messenger-matter Yukawa interactions.
Taking the concrete example of an S(3) Higgs-messenger symmetry, we demonstrate
that while the minimal implementation of this scenario suffers from a severe
mu/B_mu problem that is well-known from ordinary gauge mediation, expanding the
Higgs-messenger field content allows for the possibility that mu and B_mu can
be separately tuned, allowing for the possibility of phenomenologically viable
models of the soft supersymmetry breaking terms. We construct toy examples of
this type that are consistent with the observed 125 GeV Higgs boson mass.


title: The Case of the Disappearing (and Re-Appearing) Particle

abstract:
  A novel prediction is derived by the Two-State-Vector-Formalism (TSVF) for a
particle superposed over three boxes. Under appropriate pre- and
postselections, and with tunneling enabled between two of the boxes, it is
possible to derive not only one, but three predictions for three different
times within the intermediate interval. These predictions are moreover
contradictory. The particle (when looked for using a projective measurement)
seems to disappear from the first box where it would have been previously found
with certainty, appearing instead within the third box, to which no tunneling
is possible, and later re-appearing within the second. It turns out that local
measurement (i.e. opening one of the boxes) fails to indicate the particle's
presence, but subtler measurements performed on the two boxes together reveal
the particle's nonlocal modular momentum spatially separated from its mass.
Another advance of this setting is that, unlike other predictions of the TSVF
that rely on weak and/or counterfactual measurements, the present one uses
actual projective measurements. This outcome is then corroborated by adding
weak measurements and the Aharonov-Bohm effect. The results strengthen the
recently suggested time-symmetric Heisenberg ontology based on nonlocal
deterministic operators. They can be also tested using the newly developed
quantum router.


title:
On the relationship between set-based and network-based measures of
  gender homophily in scholarly publications

abstract:
  There is an increased interest in the scientific community in the problem of
measuring gender homophily in co-authorship on scholarly publications (Eisen,
2016). For a given set of publications and co-authorships, we assume that
author identities have not been disambiguated in that we do not know when one
person is an author on more than one paper. In this case, one way to think
about measuring gender homophily is to consider all observed co-authorship
pairs and obtain a set-based gender homophily coefficient (e.g., Bergstrom et
al., 2016). Another way is to consider papers as observed disjoint networks of
co-authors and use a network-based assortativity coefficient (e.g., Newman,
2003). In this note, we review both metrics and show that the gender homophily
set-based index is equivalent to the gender assortativity network-based
coefficient with properly weighted edges.


title: Scaling Memory-Augmented Neural Networks with Sparse Reads and Writes

abstract:
  Neural networks augmented with external memory have the ability to learn
algorithmic solutions to complex tasks. These models appear promising for
applications such as language modeling and machine translation. However, they
scale poorly in both space and time as the amount of memory grows --- limiting
their applicability to real-world domains. Here, we present an end-to-end
differentiable memory access scheme, which we call Sparse Access Memory (SAM),
that retains the representational power of the original approaches whilst
training efficiently with very large memories. We show that SAM achieves
asymptotic lower bounds in space and time complexity, and find that an
implementation runs $1,\!000\times$ faster and with $3,\!000\times$ less
physical memory than non-sparse models. SAM learns with comparable data
efficiency to existing models on a range of synthetic tasks and one-shot
Omniglot character recognition, and can scale to tasks requiring $100,\!000$s
of time steps and memories. As well, we show how our approach can be adapted
for models that maintain temporal associations between memories, as with the
recently introduced Differentiable Neural Computer.


title:
Through the Haze: a Non-Convex Approach to Blind Gain Calibration for
  Linear Random Sensing Models

abstract:
  Computational sensing strategies often suffer from calibration errors in the
physical implementation of their ideal sensing models. Such uncertainties are
typically addressed by using multiple, accurately chosen training signals to
recover the missing information on the sensing model, an approach that can be
resource-consuming and cumbersome. Conversely, blind calibration does not
employ any training signal, but corresponds to a bilinear inverse problem whose
algorithmic solution is an open issue. We here address blind calibration as a
non-convex problem for linear random sensing models, in which we aim to recover
an unknown signal from its projections on sub-Gaussian random vectors, each
subject to an unknown positive multiplicative factor (or gain). To solve this
optimisation problem we resort to projected gradient descent starting from a
suitable, carefully chosen initialisation point. An analysis of this algorithm
allows us to show that it converges to the exact solution provided a sample
complexity requirement is met, i.e., relating convergence to the amount of
information collected during the sensing process. Interestingly, we show that
this requirement grows linearly (up to log factors) in the number of unknowns
of the problem. This sample complexity is found both in absence of prior
information, as well as when subspace priors are available for both the signal
and gains, allowing a further reduction of the number of observations required
for our recovery guarantees to hold. Moreover, in the presence of noise we show
how our descent algorithm yields a solution whose accuracy degrades gracefully
with the amount of noise affecting the measurements. Finally, we present some
numerical experiments in an imaging context, where our algorithm allows for a
simple solution to blind calibration of the gains in a sensor array.


title: Concordance maps in $HFK^{-}$

abstract:
  We show that a decorated knot concordance $\mathcal{C}$ from $K_0$ to $K_1$
induces an $\mathbb{F}[U]$-module homomorphism \[G_{\mathcal{C}}:
HFK^{-}(-S^3,K_0) \to HFK^{-}(-S^3,K_1)\] which preserves the Alexander and
absolute $\mathbb{Z}_2$-Maslov gradings. Our construction generalizes the
concordance maps induced on $\widehat{HFK}$ studied by Juh\'asz and Marengon,
but uses the description of $HFK^{-}$ as a direct limit of maps between sutured
Floer homology groups discovered by Etnyre, Vela-Vick, and Zarev.


title: Direct-dynamical entanglement-discord relations

abstract:
  In this article, by considering Bell-diagonal two-qubit initial states
submitted to local dynamics generated by the phase damping, bit flip, phase
flip, bit-phase flip, and depolarizing channels, we report some elegant
direct-dynamical relations between geometric measures of entanglement and
discord. The complex scenario appearing already in this simplified case study
indicates that similarly simple relation shall hardly be found in more general
situations.


title:
The reliable solution and computation time of variable parameters
  Logistic model

abstract:
  The reliable computation time (RCT, marked as Tc) when applying a double
precision computation of a variable parameters logistic map (VPLM) is studied.
First, using the method proposed, the reliable solutions for the logistic map
are obtained. Second, for a time-dependent non-stationary parameters VPLM,
10000 samples of reliable experiments are constructed, and the mean Tc is then
computed. The results indicate that for each different initial value, the Tcs
of the VPLM are generally different. However, the mean Tc trends to a constant
value once the sample number is large enough. The maximum, minimum and probable
distribution function of Tc is also obtained, which can help us to identify the
robustness of applying a nonlinear time series theory to forecasting while
using the VPLM output. In addition, the Tc of the fixed parameter experiments
of the logistic map was obtained, and the results suggested that this Tc
matches the theoretical formula predicted value.


title:
Icon: An Interactive Approach to Train Deep Neural Networks for
  Segmentation of Neuronal Structures

abstract:
  We present an interactive approach to train a deep neural network pixel
classifier for the segmentation of neuronal structures. An interactive training
scheme reduces the extremely tedious manual annotation task that is typically
required for deep networks to perform well on image segmentation problems. Our
proposed method employs a feedback loop that captures sparse annotations using
a graphical user interface, trains a deep neural network based on recent and
past annotations, and displays the prediction output to users in almost
real-time. Our implementation of the algorithm also allows multiple users to
provide annotations in parallel and receive feedback from the same classifier.
Quick feedback on classifier performance in an interactive setting enables
users to identify and label examples that are more important than others for
segmentation purposes. Our experiments show that an interactively-trained pixel
classifier produces better region segmentation results on Electron Microscopy
(EM) images than those generated by a network of the same architecture trained
offline on exhaustive ground-truth labels.


title: Operator Variational Inference

abstract:
  Variational inference is an umbrella term for algorithms which cast Bayesian
inference as optimization. Classically, variational inference uses the
Kullback-Leibler divergence to define the optimization. Though this divergence
has been widely used, the resultant posterior approximation can suffer from
undesirable statistical properties. To address this, we reexamine variational
inference from its roots as an optimization problem. We use operators, or
functions of functions, to design variational objectives. As one example, we
design a variational objective with a Langevin-Stein operator. We develop a
black box algorithm, operator variational inference (OPVI), for optimizing any
operator objective. Importantly, operators enable us to make explicit the
statistical and computational tradeoffs for variational inference. We can
characterize different properties of variational objectives, such as objectives
that admit data subsampling---allowing inference to scale to massive data---as
well as objectives that admit variational programs---a rich class of posterior
approximations that does not require a tractable density. We illustrate the
benefits of OPVI on a mixture model and a generative model of images.


title: Geometric Dirichlet Means algorithm for topic inference

abstract:
  We propose a geometric algorithm for topic learning and inference that is
built on the convex geometry of topics arising from the Latent Dirichlet
Allocation (LDA) model and its nonparametric extensions. To this end we study
the optimization of a geometric loss function, which is a surrogate to the
LDA's likelihood. Our method involves a fast optimization based weighted
clustering procedure augmented with geometric corrections, which overcomes the
computational and statistical inefficiencies encountered by other techniques
based on Gibbs sampling and variational inference, while achieving the accuracy
comparable to that of a Gibbs sampler. The topic estimates produced by our
method are shown to be statistically consistent under some conditions. The
algorithm is evaluated with extensive experiments on simulated and real data.


title: An averaging formula for the coincidence Reidemeister trace

abstract:
  In the setting of continuous maps between compact orientable manifolds of the
same dimension, there is a well known averaging formula for the coincidence
Lefschetz number in terms of the Lefschetz numbers of lifts to some finite
covering space. We state and prove an analogous averaging formula for the
coincidence Reidemeister trace. This generalizes a recent formula in fixed
point theory by Liu and Zhao.
  We give two separate and independent proofs of our main result: one using
methods developed by Kim and the first author for averaging Nielsen numbers,
and one using an axiomatic approach for the local Reidemeister trace.
  We also give some examples and state some open questions for the
nonorientable case.


title: Interpreting Models via Single Tree Approximation

abstract:
  We propose a procedure to build a decision tree which approximates the
performance of complex machine learning models. This single approximation tree
can be used to interpret and simplify the predicting pattern of random forests
(RFs) and other models. The use of a tree structure is particularly relevant in
medical questionnaires where it enables an adaptive shortening of the
questionnaire, reducing response burden. We study the asymptotic behavior of
splits and introduce an improved splitting method designed to stabilize tree
structure. Empirical studies on both simulation and real data sets illustrate
that our method can simultaneously achieve high approximation power and
stability.


title: Model Criticism for Bayesian Causal Inference

abstract:
  The goal of causal inference is to understand the outcome of alternative
courses of action. However, all causal inference requires assumptions. Such
assumptions can be more influential than in typical tasks for probabilistic
modeling, and testing those assumptions is important to assess the validity of
causal inference. We develop model criticism for Bayesian causal inference,
building on the idea of posterior predictive checks to assess model fit. Our
approach involves decomposing the problem, separately criticizing the model of
treatment assignments and the model of outcomes. Conditioned on the assumption
of unconfoundedness---that the treatments are assigned independently of the
potential outcomes---we show how to check any additional modeling assumption.
Our approach provides a foundation for diagnosing model-based causal
inferences.


title: Professor Forcing: A New Algorithm for Training Recurrent Networks

abstract:
  The Teacher Forcing algorithm trains recurrent networks by supplying observed
sequence values as inputs during training and using the network's own
one-step-ahead predictions to do multi-step sampling. We introduce the
Professor Forcing algorithm, which uses adversarial domain adaptation to
encourage the dynamics of the recurrent network to be the same when training
the network and when sampling from the network over multiple time steps. We
apply Professor Forcing to language modeling, vocal synthesis on raw waveforms,
handwriting generation, and image generation. Empirically we find that
Professor Forcing acts as a regularizer, improving test likelihood on character
level Penn Treebank and sequential MNIST. We also find that the model
qualitatively improves samples, especially when sampling for a large number of
time steps. This is supported by human evaluation of sample quality. Trade-offs
between Professor Forcing and Scheduled Sampling are discussed. We produce
T-SNEs showing that Professor Forcing successfully makes the dynamics of the
network during training and sampling more similar.


title: Ground state properties of the Holstein-Hubbard model

abstract:
  We study the ground state properties of the Holstein-Hubbard model on some
bipartite lattices at half-filling; The ground state is proved to exhibit
ferrimagnetism whenever the electron-phonon interaction is not so strong. In
addition, the antiferromagnetic long range order is shown to exist in the
ground state. In contrast to this, we prove the absence of the long range
charge order.


title:
Effect of hexagonal patterned arrays and defect geometry on the critical
  current of superconducting films

abstract:
  Understanding the effect of pinning on the vortex dynamics in superconductors
is a key factor towards controlling critical current values. Large-scale
simulations of vortex dynamics can provide a rational approach to achieve this
goal. Here, we use the time-dependent Ginzburg-Landau equations to study thin
superconducting films with artificially created pinning centers arranged
periodically in hexagonal lattices. We calculate the critical current density
for various geometries of the pinning centers --- varying their size, strength,
and density. Furthermore, we shed light upon the influence of pattern
distortion on the magnetic-field-dependent critical current. We compare our
result directly with available experimental measurements on patterned
molybdenum-germanium films, obtaining good agreement. Our results give
important systematic insights into the mechanisms of pinning in these
artificial pinning landscapes and open a path for tailoring superconducting
films with desired critical current behavior.

categories: cond-mat.supr-con cond-mat.mes-hall cond-mat.mtrl-sci physics.comp-ph


title:
Estimation of gridded population and GDP scenarios with spatially
  explicit statistical downscaling

abstract:
  This study downscales the population and gross domestic product (GDP)
scenarios given under Shared Socioeconomic Pathways (SSPs) into 0.5-degree
grids. Our downscale approach has the following features: (i) it explicitly
considers spatial and socioeconomic interactions among cities; (ii) it utilizes
auxiliary variables, including, road network and land cover; (iii) it
endogenously estimates influence from each factor by a model ensemble approach;
(iv) it allows us controlling urban shrinkage/dispersion depending on SSPs. It
is confirmed that our downscaling results are consistent with scenario
assumptions (e.g., concentration in SSP1 and dispersion in SSP3). Besides,
while existing grid-level scenario tends to have overly-smoothed population
distributions in non-urban areas, ours does not suffer from the problem, and
captures difference in urban and non-urban areas in a more reasonable manner.