title:
Wolf-Rayet stars in the Small Magellanic Cloud: II. Analysis of the
  binaries

abstract:
  Massive WR stars are evolved massive stars characterized by strong mass-loss.
Hypothetically, they can form either as single stars or as mass donors in close
binaries. About 40% of the known WR stars are confirmed binaries, raising the
question as to the impact of binarity on the WR population. By performing a
spectral analysis of all multiple WR systems in the SMC, we obtain the full set
of stellar parameters for each individual component. Mass-luminosity relations
are tested, and the importance of the binary evolution channel is assessed. The
spectral analysis is performed with the PoWR model atmosphere code by
superimposing model spectra that correspond to each component. Evolutionary
channels are constrained using the BPASS evolution tool. Significant Hydrogen
mass fractions (0.1 - 0.4) are detected in all WN components. A comparison with
mass-luminosity relations and evolutionary tracks implies that the majority of
the WR stars in our sample are not chemically homogeneous. The WR component in
the binary AB 6 is found to be very luminous (Log L ~ 6.3 [Lsun]) given its
orbital mass (~10 Msun), presumably because of observational contamination by a
third component. Evolutionary paths derived for our objects suggest that Roche
lobe overflow had occurred in most systems, affecting their evolution. However,
the implied initial masses are large enough for the primaries to have entered
the WR phase, regardless of binary interaction. Together with the results for
the putatively single SMC WR stars, our study suggests that the binary
evolution channel does not dominate the formation of WR stars at SMC
metallicity.


title:
Soft gluon resummation for associated gluino-gaugino production at the
  LHC

abstract:
  We perform a threshold resummation calculation for the associated production
of gluinos and gauginos at the LHC to the next-to-leading logarithmic accuracy.
Analytical results are presented for the process-dependent soft anomalous
dimension and the hard function. The resummed results are matched to a full
next-to-leading order calculation, for which we have generalised the previously
known results to the case of supersymmetric scenarios featuring non-universal
squark masses. Numerically, the next-to-leading logarithmic contributions
increase the total next-to-leading order cross section by 7 to 20% for central
scale choices and gluino masses of 3 to 6 TeV, respectively, and reduce its
scale dependence typically from up to $\pm12$% to below $\pm3$%.


title: A framework for testing isotropy with the cosmic microwave background

abstract:
  We present a new framework for testing the isotropy of the Universe using
cosmic microwave background data, building on the nested-sampling ANICOSMO
code. Uniquely, we are able to constrain the scalar, vector and tensor degrees
of freedom alike; previous studies only considered the vector mode (linked to
vorticity). We employ Bianchi type VII$_h$ cosmologies to model the anisotropic
Universe, from which other types may be obtained by taking suitable limits. In
a separate development, we improve the statistical analysis by including the
effect of Bianchi power in the high-$\ell$, as well as the low-$\ell$,
likelihood. To understand the effect of all these changes, we apply our new
techniques to WMAP data. We find no evidence for anisotropy, constraining shear
in the vector mode to $(\sigma_V/H)_0 < 1.7 \times 10^{-10}$ (95% CL). For the
first time, we place limits on the tensor mode; unlike other modes, the tensor
shear can grow from a near-isotropic early Universe. The limit on this type of
shear is $(\sigma_{T,\rm reg}/H)_0 < 2.4 \times 10^{-7}$ (95% CL).


title: Physics from solar neutrinos in dark matter direct detection experiments

abstract:
  The next generation of dark matter direct detection experiments will be
sensitive to both coherent neutrino-nucleus and neutrino-electron scattering.
This will enable them to explore aspects of solar physics, perform the lowest
energy measurement of the weak angle to date, and probe contributions from new
theories with light mediators. In this article, we compute the projected
nuclear and electron recoil rates expected in several dark matter direct
detection experiments due to solar neutrinos, and use these estimates to
quantify errors on future measurements of the neutrino fluxes, weak mixing
angle and solar observables, as well as to constrain new physics in the
neutrino sector. Our analysis shows that the combined rates of solar neutrino
events in second generation experiments (SuperCDMS and LZ) can yield a
measurement of the $pp$ flux to 2.5% accuracy via electron recoil, and slightly
improve the $^8$B flux determination. Assuming a low-mass argon phase,
projected tonne-scale experiments like DARWIN can reduce the uncertainty on
both the $pp$ and boron-8 neutrino fluxes to below 1%. Finally, we use current
results from LUX, SuperCDMS and CDMSlite to set bounds on new interactions
between neutrinos and electrons or nuclei, and show that future direct
detection experiments can be used to set complementary constraints on the
parameter space associated with light mediators.


title: The High-Energy Tail of the Galactic Center Gamma-Ray Excess

abstract:
  Observations by the Fermi-LAT have uncovered a bright, spherically symmetric
excess surrounding the center of the Milky Way galaxy. The spectrum of the
gamma-ray excess peaks sharply at an energy ~2 GeV, exhibiting a hard spectrum
at lower energies, and falls off quickly above an energy ~5 GeV. The spectrum
of the excess above ~10 GeV is potentially an important discriminator between
different physical models for its origin. We focus our study on observations of
the gamma-ray excess at energies exceeding 10 GeV, finding: (1) a statistically
significant excess remains in the energy range 9.5-47.5 GeV, which is not
degenerate with known diffuse emission templates such as the Fermi Bubbles, (2)
the radial profile of the excess at high energies remains relatively consistent
with data near the spectral peak, (3) the data above ~5 GeV prefer a slightly
greater ellipticity with a major axis oriented perpendicular to the Galactic
plane. Using the recently developed non-Poissonian template fit, we find mild
evidence for a point-source origin for the high-energy excess, although given
the statistical and systematic uncertainties we show that a smooth origin of
the high-energy emission cannot be ruled out. We discuss the implication of
these findings for pulsar and dark matter models of the gamma-ray excess.
Finally we provide a number of updated measurements of the gamma-ray excess,
utilizing novel diffuse templates and the Pass 8 dataset.


title:
Spiral-induced velocity and metallicity patterns in a cosmological zoom
  simulation of a Milky Way-sized galaxy

abstract:
  We use a high resolution cosmological zoom simulation of a Milky Way-sized
halo to study the observable features in velocity and metallicity space
associated with the dynamical influence of spiral arms. For the first time, we
demonstrate that spiral arms, that form in a disc in a fully cosmological
environment with realistic galaxy formation physics, drive large-scale
systematic streaming motions. In particular, on the trailing edge of the spiral
arms the peculiar galacto-centric radial and azimuthal velocity field is
directed radially outward and azimuthally backward, whereas it is radially
inward and azimuthally forward on the leading edge. Owing to the negative
radial metallicity gradient, this systematic motion drives, at a given radius,
an azimuthal variation in the residual metallicity that is characterised by a
metal rich trailing edge and a metal poor leading edge. We show that these
signatures are theoretically observable in external galaxies with Integral
Field Unit instruments such as VLT/MUSE, and if detected, would provide
evidence for large-scale systematic radial migration driven by spiral arms.


title: Magnetic breakdown and Klein tunneling in a type-II Weyl semimetal

abstract:
  The band structure of a type-II Weyl semimetal has pairs of electron and hole
pockets that coexist over a range of energies and touch at a topologically
protected conical point. We identify signatures of this Weyl point in the
magnetic quantum oscillations of the density of states, observable in
thermodynamic properties. Tunneling between the electron and hole pockets in a
magnetic field is the momentum space counterpart of Klein tunneling at a p-n
junction in real space. This magnetic breakdown happens at a characteristic
field that vanishes when the Fermi level approaches the Weyl point.
Topologically distinct, connected or disconnected, pairs of type-II Weyl cones
can be distinguished by the qualitatively different dependence of the quantum
oscillations on the direction of the magnetic field.


title:
Planck intermediate results. XLIV. The structure of the Galactic
  magnetic field from dust polarization maps of the southern Galactic cap

abstract:
  We study the statistical properties of interstellar dust polarization at high
Galactic latitude, using the Stokes parameter Planck maps at 353 GHz. Our aim
is to advance the understanding of the magnetized interstellar medium (ISM),
and to provide a model of the polarized dust foreground for cosmic microwave
background component-separation procedures. Focusing on the southern Galactic
cap, we examine the statistical distributions of the polarization fraction
($p$) and angle ($\psi$) to characterize the ordered and turbulent components
of the Galactic magnetic field (GMF) in the solar neighbourhood. We relate
patterns at large angular scales in polarization to the orientation of the mean
(ordered) GMF towards Galactic coordinates $(l_0,b_0)=(70^\circ \pm
5^\circ,24^\circ \pm 5^\circ)$. The histogram of $p$ shows a wide dispersion up
to 25 %. The histogram of $\psi$ has a standard deviation of $12^\circ$ about
the regular pattern expected from the ordered GMF. We use these histograms to
build a phenomenological model of the turbulent component of the GMF, assuming
a uniform effective polarization fraction ($p_0$) of dust emission. To model
the Stokes parameters, we approximate the integration along the line of sight
(LOS) as a sum over a set of $N$ independent polarization layers, in each of
which the turbulent component of the GMF is obtained from Gaussian realizations
of a power-law power spectrum. We are able to reproduce the observed $p$ and
$\psi$ distributions using: a $p_0$ value of (26 $\pm$ 3)%; a ratio of 0.9
$\pm$ 0.1 between the strengths of the turbulent and mean components of the
GMF; and a small value of $N$. We relate the polarization layers to the density
structure and to the correlation length of the GMF along the LOS.


title:
Three-Index Symmetric Matter Representations of SU(2) in F-Theory from
  Non-Tate Form Weierstrass Models

abstract:
  We give an explicit construction of a class of F-theory models with matter in
the three-index symmetric (4) representation of SU(2). This matter is realized
at codimension two loci in the F-theory base where the divisor carrying the
gauge group is singular; the associated Weierstrass model does not have the
form associated with a generic SU(2) Tate model. For 6D theories, the matter is
localized at a triple point singularity of arithmetic genus g=3 in the curve
supporting the SU(2) group. This is the first explicit realization of matter in
F-theory in a representation corresponding to a genus contribution greater than
one. The construction is realized by "unHiggsing" a model with a U(1) gauge
factor under which there is matter with charge q=3. The resulting SU(2) models
can be further unHiggsed to realize non-Abelian G_2xSU(2) models with more
conventional matter content or SU(2)^3 models with trifundamental matter. The
U(1) models used as the basis for this construction do not seem to have a
Weierstrass realization in the general form found by Morrison-Park, suggesting
that a generalization of that form may be needed to incorporate models with
arbitrary matter representations and gauge groups localized on singular
divisors.


title: Constraining the Progenitor of the Type Ia Supernova SN 2012cg

abstract:
  The nature of the progenitors of SNe Ia is not yet fully understood. In the
single-degenerate (SD) scenario, the collision of the SN ejecta with its
companion star is expected to produce detectable UV emission in the first few
days after the SN explosion within certain viewing angles. It was recently
found that the $B-V$ colour of the nearby SN Ia SN 2012cg at about sixteen days
before the maximum $B$-band brightness was about 0.2 mag bluer than those of
other normal SNe Ia, which was reported as the first evidence for excess blue
light from the interaction of normal SN Ia ejecta with its companion star. In
this work, we compare current observations for SN 2012cg from its pre-explosion
phase to the late-time nebular phase with theoretical predictions from binary
evolution and population synthesis calculations for a variety of popular
progenitor scenarios. We find that a main-sequence donor or a carbon-oxygen
white dwarf donor binary system is more likely to be the progenitor of SN
2012cg. However, both scenarios also predict properties which are in
contradiction to the observed features of this system. Taking both theoretical
and observational uncertainties into account, we suggest that it might be too
early to conclude that SN 2012cg was produced from an explosion of a
Chandrasekhar-mass white dwarf in the SD scenario. Future observations and
improved detailed theoretical modelling are still required to place a more
stringent constraint on the progenitor of SN 2012cg.


title:
The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme
  Ultraviolet Spectra of K and M Dwarfs with Exoplanets

abstract:
  The ultraviolet (UV) spectral energy distributions of low-mass (K- and
M-type) stars play a critical role in the heating and chemistry of exoplanet
atmospheres, but are not observationally well-constrained. Direct observations
of the intrinsic flux of the Lyman alpha line (the dominant source of UV
photons from low-mass stars) are challenging, as interstellar HI absorbs the
entire line core for even the closest stars. To address the existing gap in
empirical constraints on the UV flux of K and M dwarfs, the MUSCLES HST
Treasury Survey has obtained UV observations of 11 nearby M and K dwarfs
hosting exoplanets. This paper presents the Lyman alpha and extreme-UV spectral
reconstructions for the MUSCLES targets. Most targets are optically inactive,
but all exhibit significant UV activity. We use a Markov Chain Monte Carlo
technique to correct the observed Lyman alpha profiles for interstellar
absorption, and we employ empirical relations to compute the extreme-UV
spectral energy distribution from the intrinsic Lyman alpha flux in ~100 {\AA}
bins from 100-1170 {\AA}. The reconstructed Lyman alpha profiles have 300 km/s
broad cores, while >1% of the total intrinsic Lyman alpha flux is measured in
extended wings between 300 km/s to 1200 km/s. The Lyman alpha surface flux
positively correlates with the MgII surface flux and negatively correlates with
the stellar rotation period. Stars with larger Lyman alpha surface flux also
tend to have larger surface flux in ions formed at higher temperatures, but
these correlations remain statistically insignificant in our sample of 11
stars. We also present HI column density measurements for 10 new sightlines
through the local interstellar medium.


title: Classification of topological phonons in linear mechanical metamaterials

abstract:
  Topological phononic crystals, alike their electronic counterparts, are
characterized by a bulk-edge correspondence where the interior of a material
dictates the existence of stable surface or boundary modes. In the mechanical
setup, such surface modes can be used for various applications such as
wave-guiding, vibration isolation, or the design of static properties such as
stable floppy modes where parts of a system move freely. Here, we provide a
classification scheme of topological phonons based on local symmetries. We
import and adapt the classification of non-interacting electron systems and
embed it into the mechanical setup. Moreover, we provide an extensive set of
examples that illustrate our scheme and can be used to generate new models in
unexplored symmetry classes. Our works unifies the vast recent literature on
topological phonons and paves the way to future applications of topological
surface modes in mechanical metamaterials.


title:
Are LGRBs biased tracers of star formation? Clues from the host galaxies
  of the Swift/BAT6 complete sample of bright LGRBs. II: star formation rates
  and metallicities at z < 1

abstract:
  Long gamma-ray bursts (LGRBs) are associated with the deaths of massive stars
and could thus be a potentially powerful tool to trace cosmic star formation.
However, especially at low redshifts (z < 1.5) LGRBs seem to prefer particular
types of environment. Our aim is to study the host galaxies of a complete
sample of bright LGRBs to investigate the impact of the environment on GRB
formation. We study host galaxy spectra of the Swift/BAT6 complete sample of 14
z < 1 bright LGRBs. We use the detected nebular emission lines to measure the
dust extinction, star formation rate (SFR) and nebular metallicity (Z) of the
hosts and supplement the data set with previously measured stellar masses
M$_{\star}$. The distributions of the obtained properties and their
interrelations (e.g. mass-metallicity and SFR-M$_{\star}$ relations) are
compared to samples of field star-forming galaxies.We find that LGRB hosts at z
< 1 have on average lower SFRs than if they were direct star-formation tracers.
By directly comparing metallicity distributions of LGRB hosts and star-forming
galaxies, we find a good match between the two populations up to Z $\sim
8.4-8.5$, after which the paucity of metal-rich LGRB hosts becomes apparent.
The LGRB host galaxies of our complete sample are not inconsistent with the
mass-metallicity relation at similar mean redshift and stellar masses. The
cutoff against high metallicities (and high masses) can explain the low SFR
values of LGRB hosts. We find a hint of increased incidence of starburst
galaxies in the Swift/BAT6 z < 1 sample with respect to that of a field
star-forming population. Given that the SFRs are low on average, the latter is
ascribed to low stellar masses. Nevertheless the limits on the completeness and
metallicity availability of current surveys, coupled with the limited number of
LGRB host galaxies, prevent us from reaching more quantitative conclusions.


title: Chemical evolution of giant molecular clouds in simulations of galaxies

abstract:
  We present an analysis of Giant Molecular Clouds (GMCs) within hydrodynamic
simulations of isolated, low-mass (M* ~ 10^9 M_sol) disc galaxies. We study the
evolution of molecular abundances and the implications for CO emission and the
X_CO conversion factor in individual clouds. We define clouds either as regions
above a density threshold n_H,min = 10 cm^-3, or using an observationally
motivated CO intensity threshold of 0.25 K km s^-1. Our simulations include a
non-equilibrium chemical model with 157 species, including 20 molecules. We
also investigate the effects of resolution and pressure floors (i.e. Jeans
limiters). We find cloud lifetimes up to ~40 Myr, with a median of 13 Myr, in
agreement with observations. At one tenth solar metallicity, young clouds
(<10-15 Myr) are underabundant in H2 and CO compared to chemical equilibrium,
by factors of ~3 and 1-2 orders of magnitude, respectively. At solar
metallicity, GMCs reach chemical equilibrium faster (within ~1 Myr). We also
compute CO emission from individual clouds. The mean CO intensity, I_CO, is
strongly suppressed at low dust extinction, A_v, and possibly saturates towards
high A_v, in agreement with observations. The I_CO - A_v relation shifts
towards higher A_v for higher metallicities and, to a lesser extent, for
stronger UV radiation. At one tenth solar metallicity, CO emission is weaker in
young clouds (<10-15 Myr), consistent with the underabundance of CO.
Consequently, X_CO decreases by an order of magnitude from 0 to 15 Myr, albeit
with a large scatter.


title:
The high mass end of the stellar mass function: Dependence on stellar
  population models and agreement between fits to the light profile

abstract:
  We quantify the systematic effects on the stellar mass function which arise
from assumptions about the stellar population, as well as how one fits the
light profiles of the most luminous galaxies at z ~ 0.1. When comparing results
from the literature, we are careful to separate out these effects. Our analysis
shows that while systematics in the estimated comoving number density which
arise from different treatments of the stellar population remain of order < 0.5
dex, systematics in photometry are now about 0.1 dex, despite recent claims in
the literature. Compared to these more recent analyses, previous work based on
Sloan Digital Sky Survey (SDSS) pipeline photometry leads to underestimates of
rho_*(> M_*) by factors of 3-10 in the mass range 10^11 - 10^11.6 M_Sun, but up
to a factor of 100 at higher stellar masses. This impacts studies which match
massive galaxies to dark matter halos. Although systematics which arise from
different treatments of the stellar population remain of order < 0.5 dex, our
finding that systematics in photometry now amount to only about 0.1 dex in the
stellar mass density is a significant improvement with respect to a decade ago.
Our results highlight the importance of using the same stellar population and
photometric models whenever low and high redshift samples are compared.


title: Orbital Stability of Multi-Planet Systems: Behavior at High Masses

abstract:
  In the coming years, high contrast imaging surveys are expected to reveal the
characteristics of the population of wide-orbit, massive, exoplanets. To date,
a handful of wide planetary mass companions are known, but only one such
multi-planet system has been discovered: HR8799. For low mass planetary
systems, multi-planet interactions play an important role in setting system
architecture. In this paper, we explore the stability of these high mass,
multi-planet systems. While empirical relationships exist that predict how
system stability scales with planet spacing at low masses, we show that
extrapolating to super-Jupiter masses can lead to up to an order of magnitude
overestimate of stability for massive, tightly packed systems. We show that at
both low and high planet masses, overlapping mean motion resonances trigger
chaotic orbital evolution, which leads to system instability. We attribute some
of the difference in behavior as a function of mass to the increasing
importance of second order resonances at high planet-star mass ratios. We use
our tailored high mass planet results to estimate the maximum number of planets
that might reside in double component debris disk systems, whose gaps may
indicate the presence of massive bodies.


title: Deep Chandra study of the truncated cool core of the Ophiuchus cluster

abstract:
  We present the results of a deep (280 ks) Chandra observation of the
Ophiuchus cluster, the second-brightest galaxy cluster in the X-ray sky. The
cluster hosts a truncated cool core, with a temperature increasing from kT~1
keV in the core to kT~9 keV at r~30 kpc. Beyond r~30 kpc the intra-cluster
medium (ICM) appears remarkably isothermal. The core is dynamically disturbed
with multiple sloshing induced cold fronts, with indications for both
Rayleigh-Taylor and Kelvin-Helmholtz instabilities. The sloshing is the result
of the strongly perturbed gravitational potential in the cluster core, with the
central brightest cluster galaxy (BCG) being displaced southward from the
global center of mass. The residual image reveals a likely subcluster south of
the core at the projected distance of r~280 kpc. The cluster also harbors a
likely radio phoenix, a source revived by adiabatic compression by gas motions
in the ICM. Even though the Ophiuchus cluster is strongly dynamically active,
the amplitude of density fluctuations outside of the cooling core is low,
indicating velocities smaller than ~100 km/s. The density fluctuations might be
damped by thermal conduction in the hot and remarkably isothermal ICM,
resulting in our underestimate of gas velocities. We find a surprising, sharp
surface brightness discontinuity, that is curved away from the core, at r~120
kpc to the southeast of the cluster center. We conclude that this feature is
most likely due to gas dynamics associated with a merger and not a result of an
extraordinary active galactic nucleus (AGN) outburst. The cooling core lacks
any observable X-ray cavities and the AGN only displays weak, point-like radio
emission, lacking lobes or jets, indicating that currently it may be largely
dormant. The lack of strong AGN activity may be due to the bulk of the cooling
taking place offset from the central supermassive black hole.


title:
p-wave Annihilating Dark Matter from a Decaying Predecessor and the
  Galactic Center Excess

abstract:
  Dark matter (DM) annihilations have been widely studied as a possible
explanation of excess gamma rays from the galactic center seen by Fermi/LAT.
However most such models are in conflict with constraints from dwarf
spheroidals. Motivated by this tension, we show that p-wave annihilating dark
matter can easily accommodate both sets of observations due to the lower DM
velocity dispersion in dwarf galaxies. Explaining the DM relic abundance is
then challenging. We outline a scenario in which the usual thermal abundance is
obtained through s-wave annihilations of a metastable particle, that eventually
decays into the p-wave annihilating DM of the present epoch. The couplings and
lifetime of the decaying particle are constrained by big bang nucleosynthesis,
the cosmic microwave background and direct detection, but significant regions
of parameter space are viable. A sufficiently large p-wave cross section can be
found by annihilation into light mediators, that also give rise to Sommerfeld
enhancement. A prediction of the scenario is enhanced annihilations in galaxy
clusters.


title:
Probing unconventional superconductivity in inversion symmetric doped
  Weyl semimetal

abstract:
  Unconventional superconductivity has been predicted to arise in the
topologically non-trivial Fermi surface of doped inversion symmetric Weyl
semimetals (WSM). In particular, Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) and
nodal BCS states are theoretically predicted to be possible superconductor
pairing states in inversion symmetric doped WSM. In an effort to resolve
preferred pairing state, we theoretically study two separate four terminal
quantum transport methods that each exhibit a unique electrical signature in
the presence of FFLO and nodal BCS states in doped WSMs. We first introduce a
Josephson junction that consists of a doped WSM and an s-wave superconductor in
which we show that the application of a transverse uniform current in s-wave
superconductor effectively cancels the momentum carried by FFLO states in doped
WSM. From our numerical analysis, we find a peak in Josephson current amplitude
at finite uniform current in s-wave superconductor that serves as an indicator
of FFLO states in doped WSMs. Furthermore, we show using a four terminal
measurement configuration that the nodal points may be shifted by an
application of transverse uniform current in doped WSM. We analyze the
topological phase transitions induced by nodal pair annihilation in
non-equilibrium by constructing the phase diagram and we find a characteristic
decrease in the density of states that serves as a signature of the quantum
critical point in the topological phase transition, thereby identifying nodal
BCS states in doped WSM.


title: Primes with restricted digits

abstract:
  Let $a_0\in\{0,\dots,9\}$. We show there are infinitely many prime numbers
which do not have the digit $a_0$ in their decimal expansion.
  The proof is an application of the Hardy-Littlewood circle method to a binary
problem, and rests on obtaining suitable `Type I' and `Type II' arithmetic
information for use in Harman's sieve to control the minor arcs. This is
obtained by decorrelating Diophantine conditions which dictate when the Fourier
transform of the primes is large from digital conditions which dictate when the
Fourier transform of numbers with restricted digits is large. These estimates
rely on a combination of the geometry of numbers, the large sieve and moment
estimates obtained by comparison with a Markov process.


title:
Electrodynamic duality and vortex unbinding in driven-dissipative
  condensates

abstract:
  We investigate the superfluid properties of two-dimensional driven Bose
liquids, such as polariton condensates, using their long-wavelength description
in terms of a compact Kardar-Parisi-Zhang (KPZ) equation for the phase
dynamics. We account for topological defects (vortices) in the phase field
through a duality mapping between the compact KPZ equation and a theory of
non-linear electrodynamics coupled to charges. Using the dual theory we derive
renormalization group equations that describe vortex unbinding in these media.
When the non-equilibirum drive is turned off, the KPZ non-linearity {\lambda}
vanishes and the RG flow gives the usual Kosterlitz-Thouless (KT) transition.
On the other hand, with non-linearity {\lambda} > 0 vortices always unbind,
even if the same system with {\lambda} = 0 is superfluid. We predict the finite
size scaling behavior of the superfluid stiffness in the crossover governed by
vortex unbinding showing its clear distinction from the scaling associated with
the KT transition.


title: Lattice duality for the compact Kardar-Parisi-Zhang equation

abstract:
  A comprehensive theory of the Kosterlitz-Thouless transition in
two-dimensional superfluids in thermal equilibrium can be developed within a
dual representation which maps vortices in the superfluid to charges in a
Coulomb gas. In this framework, the dissociation of vortex-antivortex pairs at
the critical temperature corresponds to the formation of a plasma of free
charges. The physics of vortex unbinding in driven-dissipative systems such as
fluids of light, on the other hand, is much less understood. Here we make a
crucial step to fill this gap by deriving a transformation that maps the
compact Kardar-Parisi-Zhang (KPZ) equation, which describes the dynamics of the
phase of a driven-dissipative condensate, to a dual electrodynamic theory. The
latter is formulated in terms of modified Maxwell equations for the
electromagnetic fields and a diffusion equation for the charges representing
vortices in the KPZ equation. This mapping utilizes an adaption of the Villain
approximation to a generalized Martin-Siggia-Rose functional integral
representation of the compact KPZ equation on a lattice.


title: Progressive Red Shifts in the Late-Time Spectra of Type Ia Supernovae

abstract:
  We examine the evolution of late-time, optical nebular features of Type Ia
supernovae (SNe Ia) using a sample consisting of 160 spectra of 27 normal SNe
Ia taken from the literature as well as unpublished spectra of SN 2008Q and
ASASSN-14lp. Particular attention was given to nebular features between
4000-6000 A in terms of temporal changes in width and central wavelength.
Analysis of the prominent late-time 4700 A feature shows a progressive central
wavelength shift from ~4600 A to longer wavelengths out to at least day +300
for our entire sample. We find no evidence for the feature's red-ward shift
slowing or halting at an [Fe III] blend centroid of 4701 A as has been
proposed. The width of the feature also steadily increases with a FWHM ~170 A
at day +100 growing to 200 A or more by day +350. Two weaker adjacent features
around 4850 and 5000 A exhibit very similar red shifts to that of the 4700 A
feature but show no change in width until very late times. We discuss possible
causes for the observed red-ward shifting of these late-time optical features
including contribution from [Co II] emission at early nebular epochs and the
emergence of additional features at later times. We conclude that the
ubiquitous red shift of these common late-time, nebular SN Ia spectral features
is not mainly due to a decrease in a blueshift of forbidden Fe lines but the
result, in part, of decreasing velocity and/or optical depth of permitted Fe
lines.


title:
Evolution of Binary Stars in Multiple-Population Globular Clusters - II.
  Compact Binaries

abstract:
  We present the results of a survey of N-body simulations aimed at exploring
the evolution of compact binaries in multiple-population globular clusters.We
show that as a consequence of the initial differences in the structural
properties of the first-generation (FG) and the second-generation (SG)
populations and the effects of dynamical processes on binary stars, the SG
binary fraction decreases more rapidly than that of the FG population. The
difference between the FG and SG binary fraction is qualitatively similar to
but quantitatively smaller than that found for wider binaries in our previous
investigations.The evolution of the radial variation of the binary fraction is
driven by the interplay between binary segregation, ionization and ejection.
Ionization and ejection counteract in part the effects of mass segregation but
for compact binaries the effects of segregation dominate and the inner binary
fraction increases during the cluster evolution. We explore the variation of
the difference between the FG and the SG binary fraction with the distance from
the cluster centre and its dependence on the binary binding energy and cluster
structural parameters. The difference between the binary fraction in the FG and
the SG populations found in our simulations is consistent with the results of
observational studies finding a smaller binary fraction in the SG population.


title:
A Young Cluster With an Extended Main Sequence Turnoff: Confirmation of
  a Prediction of the Stellar Rotation Scenario

abstract:
  We present Hubble Space Telescope photometry of NGC1850, a ~100 Myr, ~10^5
Msun cluster in the Large Magellanic Cloud. The colour magnitude diagram
clearly shows the presence of an extended main sequence turnoff (eMSTO). The
use of non-rotating stellar isochrones leads to an age spread of ~40 Myr. This
is in good agreement with the age range expected when the effects of rotation
in MSTO stars are wrongly interpreted in terms of age spread. We also do not
find evidence for multiple, isolated episodes of star-formation bursts within
the cluster, in contradiction to scenarios that invoke actual age spreads to
explain the eMSTO phenomenon. NGC 1850 therefore continues the trend of eMSTO
clusters where the inferred age spread is proportional to the age of the
cluster. While our results confirm a key prediction of the scenario where
stellar rotation causes the eMSTO feature, direct measurements of the
rotational rate of MSTO stars is required to definitively confirm or refute
whether stellar rotation is the origin of the eMSTO phenomenon or if it is due
to an as yet undiscovered effect.


title:
Evidence for Correlated Dynamics near the
  Berezinskii-Kosterlitz-Thouless-like Transition in Highly Underdoped
  La$_{2-x}$Sr$_{x}$CuO$_{4}$

abstract:
  A low-frequency resistance noise study in highly underdoped thick films of
La$_{2-x}$Sr$_{x}$CuO$_{4}$ ($x=0.07$ and 0.08) reveals slow, correlated
dynamics and breaking of ergodicity near the superconducting transition of the
Berezinskii-Kosterlitz-Thouless type. The observed correlated behavior is
strongly suppressed by disorder.


title: Terahertz multi-heterodyne spectroscopy using laser frequency combs

abstract:
  Frequency combs based on terahertz quantum cascade lasers feature broadband
coverage and high output powers in a compact package, making them an attractive
option for broadband spectroscopy. Here, we demonstrate the first
multi-heterodyne spectroscopy using two terahertz quantum cascade laser combs.
With just 100 $\mu$s of integration time, we achieve peak signal-to-noise
ratios exceeding 60 dB and a spectral coverage greater than 250 GHz centered at
2.8 THz. Even with room-temperature detectors we are able to achieve peak
signal-to-noise ratios of 50 dB, and as a proof-of-principle we use these combs
to measure the broadband transmission spectrum of etalon samples. Finally, we
show that with proper signal processing, it is possible to extend the
multi-heterodyne spectroscopy to quantum cascade laser combs operating in
pulsed mode, greatly expanding the range of quantum cascade lasers that could
be suitable for these techniques.


title: Epidemics in networks: A master equation approach

abstract:
  A problem closely related to epidemiology, where a subgraph of 'infected'
links is defined inside a larger network, is investigated. This subgraph is
generated from the underlying network by a random variable, which decides
whether a link is able to propagate a disease/information. The relaxation
timescale of this random variable is examined in both annealed and quenched
limits, and the effectiveness of propagation of disease/information is
analyzed. The dynamics of the model is governed by a master equation and two
types of underlying network are considered: one is scale-free and the other has
exponential degree distribution. We have shown that the relaxation timescale of
the contagion variable has a major influence on the topology of the subgraph of
infected links, which determines the efficiency of spreading of
disease/information over the network.


title:
Redshift Weights for Baryon Acoustic Oscillations : Application to Mock
  Galaxy Catalogs

abstract:
  Large redshift surveys capable of measuring the Baryon Acoustic Oscillation
(BAO) signal have proven to be an effective way of measuring the
distance-redshift relation in cosmology. Building off the work in Zhu et al.
(2015), we develop a technique to directly constrain the distance-redshift
relation from BAO measurements without splitting the sample into redshift bins.
We parametrize the distance-redshift relation, relative to a fiducial model, as
a quadratic expansion. We measure its coefficients and reconstruct the
distance-redshift relation from the expansion. We apply the redshift weighting
technique in Zhu et al. (2015) to the clustering of galaxies from 1000 QuickPM
(QPM) mock simulations after reconstruction and achieve a 0.75% measurement of
the angular diameter distance $D_A$ at $z=0.64$ and the same precision for
Hubble parameter H at $z=0.29$. These QPM mock catalogs are designed to mimic
the clustering and noise level of the Baryon Oscillation Spectroscopic Survey
(BOSS) Data Release 12 (DR12). We compress the correlation functions in the
redshift direction onto a set of weighted correlation functions. These
estimators give unbiased $D_A$ and $H$ measurements at all redshifts within the
range of the combined sample. We demonstrate the effectiveness of redshift
weighting in improving the distance and Hubble parameter estimates. Instead of
measuring at a single 'effective' redshift as in traditional analyses, we
report our $D_A$ and $H$ measurements at all redshifts. The measured fractional
error of $D_A$ ranges from 1.53% at $z=0.2$ to 0.75% at $z=0.64$. The
fractional error of $H$ ranges from 0.75% at $z=0.29$ to 2.45% at $z = 0.7$.
Our measurements are consistent with a Fisher forecast to within 10% to 20%
depending on the pivot redshift. We further show the results are robust against
the choice of fiducial cosmologies, galaxy bias models, and RSD streaming
parameters.


title: Photometric Selection of a Massive Galaxy Catalog with $z\geq0.55$

abstract:
  We present the development of a photometrically selected massive galaxy
catalog, targeting Luminous Red Galaxies (LRGs) and massive blue galaxies at
redshifts $z\geq 0.55$. Massive galaxy candidates are selected using
infrared/optical color-color cuts, with optical data from Sloan Digital Sky
Survey (SDSS) and infrared data from "unWISE" forced photometry derived from
the Wide-field Infrared Survey Explorer (WISE). The selection method is based
on previously developed techniques to select LRGs with $z>0.5$, and is
optimized using receiver operating characteristic (ROC) curves. The catalog
contains 16,191,145 objects, selected over the full SDSS DR10 footprint. The
redshift distribution of the resulting catalog is estimated using spectroscopic
redshifts from the DEEP2 Galaxy Redshift Survey and photometric redshifts from
COSMOS. Restframe $U-B$ colors from DEEP2 are used to estimate LRG selection
efficiency. Using DEEP2, the resulting catalog has average redshift $z=0.65$,
with standard deviation $\sigma = 2.0$, and average restframe $U-B=1.0$, with
standard deviation $\sigma=0.27$. Using COSMOS, the resulting catalog has
average redshift $z=0.60$, with standard deviation $\sigma = 1.8$. We estimate
34% of the catalog to be blue galaxies with $z\geq0.55$. An estimated 9.6% of
selected objects are blue sources with redshift $z<0.55$. Stellar contamination
is estimated to be 1.8%.


title: Ferromagnetism in a Repulsive Atomic Fermi Gas with Correlated Disorder

abstract:
  We investigate the zero-temperature ferromagnetic behavior of a two-component
repulsive Fermi gas in the presence of a correlated random field that
represents an optical speckle pattern. The density is tuned so that the
(noninteracting) Fermi energy is close to the mobility edge of the Anderson
localization transition. We employ quantum Monte Carlo simulations to determine
various ground-state properties, including the equation of state, the magnetic
susceptibility, and the energy of an impurity immersed in a polarized Fermi gas
(repulsive polaron). In the weakly interacting limit, the magnetic
susceptibility is found to be suppressed by disorder. However, it rapidly
increases with the interaction strength, and it diverges at a much weaker
interaction strength compared to the clean gas. Both the transition from the
paramagnetic phase to the partially ferromagnetic phase, and the one from the
partially to the fully ferromagnetic phase are strongly favored by disorder,
indicating a case of order induced by disorder.


title: Evolution of Molecular and Atomic Gas Phases in the Milky Way

abstract:
  We analyze radial and azimuthal variations of the phase balance between the
molecular and atomic ISM in the Milky Way. In particular, the azimuthal
variations -- between spiral arm and interarm regions -- are analyzed without
any explicit definition of spiral arm locations. We show that the molecular gas
mass fraction, i.e., fmol=H2/ (HI+H2) in mass, varies predominantly in the
radial direction: starting from ~100% at the center, remaining ~>50% (~>60%) to
R~6kpc, and decreasing to ~10-20% (~50%) at R=8.5 kpc when averaged over the
whole disk thickness (in the mid plane). Azimuthal, arm-interarm variations are
secondary: only ~20%, in the globally molecule-dominated inner MW, but becoming
larger, ~40-50%, in the atom-dominated outskirts. This suggests that in the
inner MW, the gas stays highly molecular (fmol>50%) as it goes from an interarm
region, into a spiral arm, and back into the next interarm region. Stellar
feedback does not dissociate molecules much, and the coagulation and
fragmentation of molecular clouds dominate the evolution of the ISM at these
radii. The trend differs in the outskirts, where the gas phase is globally
atomic (fmol<50%). The HI and H2 phases cycle through spiral arm passage there.
These different regimes of ISM evolution are also seen in external galaxies
(e.g., LMC, M33, and M51). We explain the radial gradient of fmol by a simple
flow continuity model. The effects of spiral arms on this analysis are
illustrated in Appendix.


title: (Not so) pure Lovelock Kasner metrics

abstract:
  The gravitational interaction is expected to be modified for very short
distances. This is particularly important in situations in which the curvature
of spacetime is large in general, such as close to the initial cosmological
singularity. The gravitational dynamics is then captured by the higher
curvature terms in the action, making it difficult to reliably extrapolate any
prediction of general relativity. In this note we review pure Lovelock
equations for Kasner-type metrics. These equations correspond to a single $N$th
order Lovelock term in the action in $d=2N+1,\,2N+2$ dimensions, and they
capture the relevant gravitational dynamics when aproaching the big-bang
singularity within the Lovelock family of theories. These are classified in
several isotropy types. Some of these families correspond to degenerate classes
of solutions, such that their dynamics is not completely determined by the
equations of pure Lovelock gravity. Instead, these Kasner solutions become
sensitive to the subleading terms in the Lovelock series.


title:
Towards personalized causal inference of medication response in mobile
  health: an instrumental variable approach for randomized trials with
  imperfect compliance

abstract:
  Mobile health studies can leverage longitudinal sensor data from smartphones
to guide the application of personalized medical interventions. In this paper,
we propose that adoption of an instrumental variable approach for randomized
trials with imperfect compliance provides a natural framework for personalized
causal inference of medication response in mobile health studies. Randomized
treatment suggestions can be easily delivered to the study participants via
electronic messages popping up on the smart-phone screen. Under quite general
assumptions we can identify the causal effect of the actual treatment on the
response in the presence of unobserved confounders. We implement a personalized
randomization test of the null hypothesis of no causal effect of treatment on
response, and evaluate its performance in a large scale simulation study
encompassing data generated from linear and non-linear time series models under
several simulation conditions. In particular, we evaluate the empirical power
of the proposed test under varying degrees of compliance between the suggested
and actual treatment adopted by the participant. Our investigations provide
encouraging results in terms of power and control of type I error rates.
Finally, we compare the proposed instrumental variable approach to a simple
intent-to-treat strategy, and develop randomization confidence intervals for
the causal effects.


title:
Capacity Achieving Distributions & Information Lossless Randomized
  Strategies for Feedback Channels with Memory: The LQG Theory of Directed
  Information-Part II

abstract:
  A methodology is developed to realized optimal channel input conditional
distributions, which maximize the finite-time horizon directed information, for
channels with memory and feedback, by information lossless randomized
strategies. The methodology is applied to general Time-Varying Multiple Input
Multiple Output (MIMO) Gaussian Linear Channel Models (G-LCMs) with memory,
subject to average transmission cost constraints of quadratic form. The
realizations of optimal distributions by randomized strategies are shown to
exhibit a decomposion into a deterministic part and a random part. The
decomposition reveals the dual role of randomized strategies, to control the
channel output process and to transmit new information over the channels.
Moreover, a separation principle is shown between the computation of the
optimal deterministic part and the random part of the randomized strategies.
The dual role of randomized strategies generalizes the
Linear-Quadratic-Gaussian (LQG) stochastic optimal control theory to directed
information pay-offs. The characterizations of feedback capacity are obtained
from the per unit time limits of finite-time horizon directed information,
without imposing \'a priori assumptions, such as, stability of channel models
or ergodicity of channel input and output processes. For time-invariant MIMO
G-LCMs with memory, it is shown that whether feedback increases capacity, is
directly related to the channel parameters and the transmission cost function,
through the solutions of Riccati matrix equations, and moreover for unstable
channels, feedback capacity is non-zero, provided the power exceeds a critical
level.


title: On the Colmez conjecture for non-abelian CM fields

abstract:
  The Colmez conjecture relates the Faltings height of an abelian variety with
complex multiplication by the ring of integers of a CM field $E$ to logarithmic
derivatives of certain Artin $L$--functions at $s=0$. In this paper, we prove
that if $F$ is any fixed totally real number field of degree $[F:\mathbb{Q}]
\geq 3$, then there are infinitely many CM extensions $E/F$ such that
$E/\mathbb{Q}$ is $\textit{non-abelian}$ and the Colmez conjecture is true for
$E$. Moreover, these CM extensions are explicitly constructed to be ramified at
"arbitrary" prescribed sets of prime ideals of $F$.
  We also prove that the Colmez conjecture is true for a generic class of
non-abelian CM fields called Weyl CM fields, and use this to develop an
arithmetic statistics approach to the Colmez conjecture based on counting CM
fields of fixed degree and bounded discriminant.
  We illustrate these results by evaluating the Faltings height of the Jacobian
of a genus 2 hyperelliptic curve with complex multiplication by a non-abelian
quartic CM field in terms of the Barnes double Gamma function at algebraic
arguments. This can be seen as an explicit non-abelian Chowla-Selberg formula.
  A crucial input to the proofs is an averaged version of the Colmez conjecture
which was recently proved independently by Andreatta-Goren-Howard-Madapusi Pera
and Yuan-Zhang.


title:
Calculation of phases of np- scattering up to Tlab=3 GeV for potentials
  Argonne group on the phase-function method

abstract:
  For calculation of the single-channel nucleon-nucleon scattering a
phase-functions method has been proposed. Using a phase-functions method the
following phase shifts of a np- scattering numerically for 1S0-, 1P1-, 3P0-,
3P1-, 1D2-, 3D2-, 1F3-, 3F3-, 1G4-, 3G4- states are calculated. The
calculations has been performed using realistic nucleon-nucleon potentials
Argonne group (Av18, Av14sscc, Av8', Av8'sscc, Av6', Av4', Av2'). Obtained
phase shifts are in good agreement with the results obtained in the framework
of other methods. Using the obtained phase shifts we have calculated the full
cross-section np- scattering.


title:
Model-independent constraints on modified gravity from current data and
  from the Euclid and SKA future surveys

abstract:
  The aim of this paper is to constrain modified gravity with redshift space
distortion observations and supernovae measurements. Compared with a standard
LCDM analysis, we include three additional free parameters, namely the initial
conditions of the matter perturbations,the overall perturbation normalization,
and a scale-dependent Y parameter modifying the Poisson equation, in an attempt
to perform a more model-independent analysis. First, we constrain the Poisson
parameter Y (also called Geff ) by using currently available fsigma_8 data and
the recent SN catalog JLA. We find that the inclusion of the additional free
parameters makes the constraints significantly weaker than when fixing them to
the standard cosmological value. Second, we constrain Y by using forecast
growth-rate data for Euclid and SKA missions. Here again we point out the
weakening of the constraints when the additional parameters are included.
Finally, we adopt as modified gravity Poisson parameter the specific Horndeski
form, and use scale-dependent forecasts to build an exclusion plot for the
Yukawa potential akin to the ones realized in laboratory experiments, both for
the Euclid and the SKA surveys.


title:
Bessel operators on Jordan pairs and small representations of semisimple
  Lie groups

abstract:
  We provide a uniform construction of $L^2$-models for all small unitary
representations in degenerate principal series of semisimple Lie groups which
are induced from maximal parabolic subgroups with abelian nilradical. This
generalizes previous constructions to the case of a maximal parabolic subgroup
which is not necessarily conjugate to its opposite, and hence the previously
used Jordan algebra methods have to be generalized to Jordan pairs.
  The crucial ingredients for the construction of the $L^2$-models are the Lie
algebra action and the spherical vector. Working in the so-called Fourier
transformed picture of the degenerate principal series, the Lie algebra action
is given in terms of Bessel operators on Jordan pairs. We prove that precisely
for those parameters of the principal series where small quotients occur, the
Bessel operators are tangential to certain submanifolds. Further, we show that
the small quotients are unitarizable if and only if these submanifolds carry
equivariant measures. In this case we can express the spherical vectors in
terms of multivariable K-Bessel functions, and some delicate estimates for
these Bessel functions imply the existence of the $L^2$-models.


title: Boundaries and automorphisms of hierarchically hyperbolic spaces

abstract:
  Hierarchically hyperbolic spaces provide a common framework for studying
mapping class groups of finite type surfaces, Teichm\"uller space, right-angled
Artin groups, and many other cubical groups. Given such a space $\mathcal X$,
we build a bordificationcompatible with the hierarchically hyperbolic
structure. If $\mathcal X$ is proper, we get a compactification of $\mathcal
X$; we also prove that our construction generalizes the Gromov boundary of a
hyperbolic space. In our first main set of applications, we introduce a notion
of geometrical finiteness for hierarchically hyperbolic subgroups of
hierarchically hyperbolic groups in terms of boundary embeddings. As primary
examples of geometrical finiteness, we prove that the natural inclusions of
finitely generated Veech groups and the Leininger-Reid combination subgroups
extend to continuous embeddings of their Gromov boundaries into the boundary of
the mapping class group, both of which fail to happen with the Thurston
compactification of Teichm\"uller space. Our second main set of applications
are dynamical and structural, built upon our classification of automorphisms of
hierarchically hyperbolic spaces and analysis of how the various types of
automorphisms act on the boundary. We prove a generalization of the
Handel-Mosher "omnibus subgroup theorem" for mapping class groups to all
hierarchically hyperbolic groups, obtain a new proof of the Caprace-Sageev
rank-rigidity theorem for many CAT(0) cube complexes, and identify the boundary
of a hierarchically hyperbolic group as its Poisson boundary; these results
rely on a theorem detecting \emph{irreducible axial} elements of a group acting
on a hierarchically hyperbolic space (which generalize pseudo-Anosov elements
of the mapping class group and rank-one isometries of a cube complex not
virtually stabilizing a hyperplane).


title: Optimal Multicasting in Hybrid RF/FSO DTNs

abstract:
  The multi-copy routing paradigm in Delay Tolerant Networks (DTNs) implies
that increasing contact bandwidth leads to a decrease in data delivery delay
and an improvement in throughput. With Hybrid Radio Frequency/Free Space
Optical (RF/FSO) PHY layers, the high data rate FSO links can be used to
increase the contact bandwidth. However, due to the highly directional nature
of FSO links, broadcasting is difficult. A naive broadcast strategy where the
beam divergence angle is increased to include many nodes in the broadcast set
results in low data rate, and does not always result in the minimum achievable
delay.
  In this work we develop an optimal multicast algorithm for hybrid RF/FSO
networks. We show that the problem is an abstraction of the minimum weight set
cover problem which is known to be NP-hard. A computationally cheap greedy
local optimum heuristic is proposed. A comprehensive evaluation using delay,
throughput and computation time as metrics is performed using various
solutions. These extensive evaluations show that our solution outperforms both
naive broadcast and multiple unicast, taking 95% less time as compared to the
exact algorithm, while providing comparable performance.


title:
Information Structures of Maximizing Distributions of Feedback Capacity
  for General Channels with Memory & Applications

abstract:
  For any class of channel conditional distributions, with finite memory
dependence on channel input RVs $A^n {\stackrel{\triangle}{=}} \{A_i: i=0,
\ldots, n\}$ or channel output RVs $B^n {\stackrel{\triangle}{=}} \{B_i: i=0,
\ldots, n\}$ or both, we characterize the sets of channel input distributions,
which maximize directed information defined by $ I(A^n \rightarrow B^n)
{\stackrel{\triangle}{=}} \sum_{i=0}^n I(A^i;B_i|B^{i-1}) $ and we derive the
corresponding expressions, called "characterizations of Finite Transmission
Feedback Information (FTFI) capacity". The main theorems state that optimal
channel input distributions occur in subsets ${\cal P}_{[0,n]}^{CI}\subseteq
{\cal P}_{[0,n]} {\stackrel{\triangle}{=}}\big\{ {\bf P}_{A_i|A^{i-1},
B^{i-1}}: i=0, \ldots, n\big\}$, which satisfy conditional independence on past
information. We derive similar characterizations, when general transmission
cost constraints are imposed. Moreover, we also show that the structural
properties apply to general nonlinear and linear autoregressive channel models
defined by discrete-time recursions on general alphabet spaces, and driven by
arbitrary distributed noise processes. We derive these structural properties by
invoking stochastic optimal control theory and variational equalities of
directed information, to identify tight upper bounds on $I(A^n \rightarrow
B^n)$, which are achievable over subsets of conditional distributions ${\cal
P}_{[0,n]}^{CI} \subseteq {\cal P}_{[0,n]}$, which satisfy conditional
independence and they are specified by the dependence of channel distributions
and transmission cost functions on inputs and output symbols. We apply the
characterizations to recursive Multiple Input Multiple Output Gaussian Linear
Channel Models with limited memory and we show a separation principle between
the computation of the elements of the optimal strategies.


title: Bayesian Local Extrema Splines

abstract:
  We consider the problem of shape restricted nonparametric regression on a
closed set X ?\in R; where it is reasonable to assume the function has no more
than H local extrema interior to X: Following a Bayesian approach we develop a
nonparametric prior over a novel class of local extrema splines. This approach
is shown to be consistent when modeling any continuously differentiable
function within the class of functions considered, and is used to develop
methods for hypothesis testing on the shape of the curve. Sampling algorithms
are developed, and the method is applied in simulation studies and data
examples where the shape of the curve is of interest.


title:
Optimal undulating swimming for a single fish-like body and for a pair
  of interacting swimmers

abstract:
  We establish through numerical simulation conditions for optimal undulatory
propulsion for a single fish, and for a pair of hydrodynamically interacting
fish, accounting for linear and angular recoil. We first employ systematic 2D
simulations to identify conditions for minimal propulsive power of a
self-propelled fish, and continue with targeted 3D simulations for a danio-like
fish. We find that the Strouhal number, phase angle between heave and pitch at
the trailing edge, and angle of attack are principal parameters. Angular recoil
has significant impact on efficiency, while optimized body bending requires
maximum bending amplitude upstream of the trailing edge. For 2D simulations,
imposing a deformation based on measured displacement for carangiform swimming
provides efficiency of 40%, which increases for an optimized profile to 57%;
for a 3D fish, the corresponding increase is from 22% to 35%; all at Reynolds
number 5000.
  Next, we turn to 2D simulation of two hydrodynamically interacting fish. We
find that the upstream fish benefits energetically only for small distances. In
contrast, the downstream fish can benefit at any position that allows
interaction with the upstream wake, provided its body motion is timed
appropriately with respect to the oncoming vortices. For an in-line
configuration, one body length apart, the optimal efficiency of the downstream
fish can increase to 66%; for an offset arrangement it can reach 81%. This
proves that in groups of fish, energy savings can be achieved for downstream
fish through interaction with oncoming vortices, even when the downstream fish
lies directly inside the jet-like flow of an upstream fish.


title: Nonlinear mode coupling in whispering-gallery-mode resonators

abstract:
  We present a first principle derivation of the coupled nonlinear
Schr\"{o}dinger equations that govern the interaction between two families of
modes with different transverse profiles in a generic whispering-gallery-mode
resonator. We find regions of modulational instability and the existence of
trains of bright solitons both in the normal and in the anomalous dispersion
regime.


title: Sparse matrices for weighted sparse recovery

abstract:
  We derived the first sparse recovery guarantees for weighted $\ell_1$
minimization with sparse random matrices and the class of weighted sparse
signals, using a weighted versions of the null space property to derive these
guarantees. These sparse matrices from expender graphs can be applied very fast
and have other better computational complexities than their dense counterparts.
In addition we show that, using such sparse matrices, weighted sparse recovery
with weighted $\ell_1$ minimization leads to sample complexities that are
linear in the weighted sparsity of the signal and these sampling rates can be
smaller than those of standard sparse recovery. Moreover, these results reduce
to known results in standard sparse recovery and sparse recovery with prior
information and the results are supported by numerical experiments.


title:
The first spectropolarimetric monitoring of the peculiar O4Ief
  supergiant zeta Puppis

abstract:
  The origin of the magnetic field in massive O-type stars is still under
debate. To model the physical processes responsible for the generation of O
star magnetic fields, it is important to understand whether correlations
between the presence of a magnetic field and stellar evolutionary state,
rotation velocity, kinematical status, and surface composition can be
identified. The O4Ief supergiant zeta Pup is a fast rotator and a runaway star,
which may be a product of a past binary interaction, possibly having had an
encounter with the cluster Trumper 10 some 2Myr ago. The currently available
observational material suggests that certain observed phenomena in this star
may be related to the presence of a magnetic field. We acquired
spectropolarimetric observations of zeta Pup with FORS2 mounted on the 8-m Antu
telescope of the VLT to investigate if a magnetic field is indeed present in
this star. We show that many spectral lines are highly variable and probably
vary with the recently detected period of 1.78d. No magnetic field is detected
in zeta Pup, as no magnetic field measurement has a significance level higher
than 2.4sigma. Still, we studied the probability of a single sinusoidal
explaining the variation of the longitudinal magnetic field measurements.


title:
Studying the nucleus of comet 9P/Tempel 1 using the structure of the
  Deep Impact ejecta cloud at the early stages of its development

abstract:
  We present an attempt to extract information about the comet 9P/Tempel 1
nucleus from the characteristics of the ejecta cloud produced by the impactor
of the Deep Impact mission. For this purpose we use two techniques. We first
study the shadow cast on the nucleus surface by the ejecta cloud and
investigate how areas of different brightness are related to the varying
optical thickness or albedo of the ejecta cloud. The shadow was seen during the
first 2.0 seconds after the impact (afterward it became obscured by the ejecta
cloud). We have found that all brightness variations in the shadow are the
result of the surface inhomogeneities, indicating that during first 2.0 seconds
the ejecta cloud was homogeneous within the MRI spatial resolution. Our second
technique is to study the obscuration of the nucleus limb by the ejecta. This
study covers the period 0.76- 68.8 seconds after impact and is based on
comparison of the ejecta cloud brightness on the limb and just beyond the limb.
At this stage we do see inhomogeneities in the ejecta cloud that relate to the
albedo and optical thickness variations in the ejected dust. Specifically, we
have found two distinct bands of low optical thickness and one band of a high
optical thickness. Based on crater formation ideas we estimate the depth of
excavation of the ejected material for the found inhomogeneities and, thus,
define a potential layering structure for the comet nucleus, Our estimates
suggest that the low-optical thickness material was excavated from a depth of
15-18 and 30-32 meters in the case the porous nucleus material and 37-46 and
87-93 meters in the case of a non-porous nucleus material, and a layer of high
optical thickness originated from the depth 9-11 m for porous material or 20-23
m for non-porous material. Based on the crater diameter estimates, we expect
that the real depth of the layers is between these two cases.


title:
Science Concierge: A fast content-based recommendation system for
  scientific publications

abstract:
  Finding relevant publications is important for scientists who have to cope
with exponentially increasing numbers of scholarly material. Algorithms can
help with this task as they help for music, movie, and product recommendations.
However, we know little about the performance of these algorithms with
scholarly material. Here, we develop an algorithm, and an accompanying Python
library, that implements a recommendation system based on the content of
articles. Design principles are to adapt to new content, provide near-real time
suggestions, and be open source. We tested the library on 15K posters from the
Society of Neuroscience Conference 2015. Human curated topics are used to cross
validate parameters in the algorithm and produce a similarity metric that
maximally correlates with human judgments. We show that our algorithm
significantly outperformed suggestions based on keywords. The work presented
here promises to make the exploration of scholarly material faster and more
accurate.


title:
Modified $f(R)$ Gravity and Thermodynamics of Time-Dependent Wormholes
  at Event Horizon

abstract:
  In the context of modified $f(R)$ gravity theory, we study time-dependent
wormhole spacetimes in the radiation background. In this framework, we attempt
to generalize the thermodynamic properties of time-dependent wormholes in
$f(R)$ gravity. Finally, at event horizon, the rate of change of total entropy
has been discussed.


title: Ratchet Effects in Active Matter Systems

abstract:
  Ratchet effects can arise for single or collectively interacting Brownian
particles on an asymmetric substrate when a net dc transport is produced by an
externally applied ac driving force or by periodically flashing the substrate.
Recently, a new class of active ratchet systems has been realized through the
use of active matter, which are self-propelled units that can be biological or
non-biological in nature. When active materials such as swimming bacteria
interact with an asymmetric substrate, a net dc directed motion can arise even
without external driving, opening a wealth of possibilities such as sorting,
cargo transport, or micromachine construction. We review the current status of
active matter ratchets for swimming bacteria, cells, active colloids, and
swarming models, focusing on the role of particle-substrate interactions. We
describe ratchet reversals produced by collective effects and the use of active
ratchets to transport passive particles. We discuss future directions including
deformable substrates or particles, the role of different swimming modes,
varied particle-particle interactions, and non-dissipative effects.


title: Vectorial scanning force microscopy using a nanowire sensor

abstract:
  Self-assembled nanowire (NW) crystals can be grown into nearly defect-free
nanomechanical resonators with exceptional properties, including small motional
mass, high resonant frequency, and low dissipation. Furthermore, by virtue of
slight asymmetries in geometry, a NW's flexural modes are split into doublets
oscillating along orthogonal axes. These characteristics make bottom-up grown
NWs extremely sensitive vectorial force sensors. Here, taking advantage of its
adaptability as a scanning probe, we use a single NW to image a sample surface.
By monitoring the frequency shift and direction of oscillation of both modes as
we scan above the surface, we construct a map of all spatial tip-sample force
derivatives in the plane. Finally, we use the NW to image electric force fields
distinguishing between forces arising from the NW charge and polarizability.
This universally applicable technique enables a form of atomic force microscopy
particularly suited to mapping the size and direction of weak tip-sample
forces.


title: GPU-accelerated stochastic predictive control of drinking water networks

abstract:
  Despite the proven advantages of scenario-based stochastic model predictive
control for the operational control of water networks, its applicability is
limited by its considerable computational footprint. In this paper we fully
exploit the structure of these problems and solve them using a proximal
gradient algorithm parallelizing the involved operations. The proposed
methodology is applied and validated on a case study: the water network of the
city of Barcelona.


title:
A Dynamic Bayesian Network Model for Inventory Level Estimation in
  Retail Marketing

abstract:
  Many retailers today employ inventory management systems based on Re-Order
Point Policies, most of which rely on the assumption that all decreases in
product inventory levels result from product sales. Unfortunately, it usually
happens that small but random quantities of the product get lost, stolen or
broken without record as time passes, e.g., as a consequence of shoplifting.
This is usual for retailers handling large varieties of inexpensive products,
e.g., grocery stores. In turn, over time these discrepancies lead to stock
freezing problems, i.e., situations where the system believes the stock is
above the re-order point but the actual stock is at zero, and so no
replenishments or sales occur. Motivated by these issues, we model the
interaction between sales, losses, replenishments and inventory levels as a
Dynamic Bayesian Network (DBN), where the inventory levels are unobserved
(i.e., hidden) variables we wish to estimate. We present an
Expectation-Maximization (EM) algorithm to estimate the parameters of the sale
and loss distributions, which relies on solving a one-dimensional dynamic
program for the E-step and on solving two separate one-dimensional nonlinear
programs for the M-step.


title:
Fowler-Nordheim emission modified by laser pulses in the adiabatic
  regime

abstract:
  We investigate enhanced field emission due to a continuous or pulsed
oscillating field added to a constant electric field $E$ at the emitter
surface. When the frequency of oscillation, field strength, and property of the
emitter material satisfy the Keldysh condition $\gamma<1/2$ one can use the
adiabatic approximation for treating the oscillating field, i.e. consider the
tunneling through the instantaneous Fowler-Nordheim barrier created by both
fields. Due to the great sensitivity of the emission to the field strength the
average tunneling current can be much larger than the current produced by only
the constant field.
  We carry out the computations for arbitrary strong constant electric fields,
beyond the commonly used Fowler-Nordheim approximation which exhibit in
particular an important property of the wave function inside the potential
barrier where it is found to be monotonically decreasing without oscillations.


title:
Inherent Structure Energy is a Good Indicator of Molecular Mobility in
  Glasses

abstract:
  Glasses produced via physical vapor deposition can display greater kinetic
stability and lower enthalpy than glasses prepared by liquid cooling. While the
reduced enthalpy has often been used as a measure of the stability, it is not
obvious whether dynamic measures of stability provide the same view. Here, we
study dynamics in vapor-deposited and liquid-cooled glass films using molecular
simulations of a bead-spring polymer model as well as a Lennard-Jones binary
mixture in two and three dimensions. We confirm that the dynamics in
vapor-deposited glasses is indeed slower than in ordinary glasses. We further
show that the inherent structure energy is a good reporter of local dynamics,
and that aged systems and glasses prepared by cooling at progressively slower
rates exhibit the same behavior as vapor-deposited materials when they both
have the same inherent structure energy. These findings suggest that the
stability inferred from measurements of the energy is also manifested in
dynamic observables, and they strengthen the view that vapor deposition
processes provide an effective strategy for creation of stable glasses.


title:
Ab-initio prediction of fast non-equilibrium transport of nascent
  polarons in SrI$_2$: A key to high-performance scintillation

abstract:
  The excellent light yield proportionality of europium-doped strontium iodide
(SrI$_2$:Eu) has resulted in state-of-the-art $\gamma$-ray detectors with
remarkably high energy resolution, far exceeding that of most halide compounds.
In this class of materials the formation of self-trapped hole polarons is very
common. However, polaron formation is usually expected to limit carrier
mobilities and has been associated with poor scintillator light-yield
proportionality and resolution. Here, using a recently developed
first-principles method, we perform an unprecedented study of polaron transport
in SrI$_2$, both for equilibrium polarons, as well as nascent polarons
immediately following a self-trapping event. As a result, we put forward a
rationale for the unexpected high energy resolution of SrI$_2$. We identify
nine stable hole polaron configurations, which consist of dimerized iodine
pairs with polaron binding energies of up to 0.5\,eV. They are connected by a
complex potential energy landscape that comprises 66 unique nearest-neighbor
migration paths. \textit{Ab initio} molecular dynamics simulations reveal that
a large fraction of polarons is born into configurations that migrate
practically barrier free at room temperature. As a result, carriers created
during $\gamma$-irradiation can quickly diffuse away reducing the chance for
non-linear recombination reactions that are the primary culprits for
non-proportionality and resolution reduction. This leads to the conclusion that
the flat, albeit complex, landscape for polaron migration in SrI$_2$ is key for
understanding its outstanding performance. This insight provides important
guidance not only for the future development of high-performance scintillators
but also of other materials, for which large polaron mobilities are crucial
such as batteries and solid state ionic conductors.


title:
Using the Steinberg algebra model to determine the center of any Leavitt
  path algebra

abstract:
  Given an arbitrary graph, we describe the center of its Leavitt path algebra
over a commutative unital ring. Our proof uses the Steinberg algebra model of
the Leavitt path algebra. A key ingredient is a characterization of compact
open invariant subsets of the unit space of the graph groupoid in terms of the
underlying graph: an open invariant subset is compact if and only if its
associated hereditary and saturated set of vertices satisfies Condition (F). We
also give a basis of the center. Its cardinality depends on the number of
minimal compact open invariant subsets of the unit space.


title:
Capabilities of Earth-based radar facilities for near-Earth asteroid
  observations

abstract:
  We evaluated the planetary radar capabilities at Arecibo, the Goldstone 70-m
DSS-14 and 34-m DSS-13 antennas, the 70-m DSS-43 antenna at Canberra, the Green
Bank Telescope, and the Parkes Radio Telescope in terms of their relative
sensitivities and the number of known near-Earth asteroids (NEAs) detectable
per year in monostatic and bistatic configurations. In the 2015 calendar year,
monostatic observations with Arecibo and DSS-14 were capable of detecting 253
and 131 NEAs respectively, with signal-to-noise ratios (SNRs) greater than
30/track. Combined, the two observatories were capable of detecting 276 NEAs.
Of these, Arecibo detected 77 and Goldstone detected 32, or 30% and 24% the
numbers that were possible. The two observatories detected an additional 18 and
7 NEAs respectively, with SNRs of less than 30/track. This indicates that a
substantial number of potential targets are not being observed. The bistatic
configuration with DSS-14 transmitting and the Green Bank Telescope receiving
was capable of detecting about 195 NEAs, or ~50% more than with monostatic
observations at DSS-14. Most of the detectable asteroids were targets of
opportunity that were discovered less than 15 days before the end of their
observing windows. About 50% of the detectable asteroids have absolute
magnitudes > 25, which corresponds diameters < ~30 m.


title: Mapped tent pitching schemes for hyperbolic systems

abstract:
  A spacetime domain can be progressively meshed by tent shaped objects.
Numerical methods for solving hyperbolic systems using such tent meshes to
advance in time have been proposed previously. Such schemes have the ability to
advance in time by different amounts at different spatial locations. This paper
explores a technique by which standard discretizations, including explicit time
stepping, can be used within tent-shaped spacetime domains. The technique
transforms the equations within a spacetime tent to a domain where space and
time are separable. After detailing techniques based on this mapping, several
examples including the acoustic wave equation and the Euler system are
considered.


title: Markovian Quantum Master Equation beyond Adiabatic Regime

abstract:
  By introducing a temporal change timescale $\tau_{\text{A}}(t)$ for the
time-dependent system Hamiltonian, a general formulation of the Markovian
quantum master equation is given to go well beyond the adiabatic regime. In
appropriate situations, the framework is well justified even if
$\tau_{\text{A}}(t)$ is faster than the decay timescale of the bath correlation
function. An application to the dissipative Landau-Zener model demonstrates
this general result. The findings are applicable to a wide range of fields,
providing a basis for quantum control beyond the adiabatic regime.

categories: cond-mat.stat-mech cond-mat.mes-hall cond-mat.supr-con quant-ph


title:
A Comprehensive Study of Low-Energy Response for Xenon-Based Dark Matter
  Experiments

abstract:
  We report a comprehensive study of the energy response to low-energy recoils
in dual-phase xenon-based dark matter experiments. A recombination model is
developed to explain the recombination probability as a function of recoil
energy at zero field and non-zero field. The role of e-ion recombination is
discussed for both parent recombination and volume recombination. We find that
the volume recombination under non-zero field is constrained by a plasma
effect, which is caused by a high density of charge carriers along the
ionization track forming a plasma-like cloud of charge that shields the
interior from the influence of the external electric field. Subsequently, the
plasma time that determines the volume recombination probability at non-zero
field is demonstrated to be different between electronic recoils and nuclear
recoils due to the difference of ionization density between two processes. We
show a weak field-dependence of the plasma time for nuclear recoils and a
stronger field-dependence of the plasma time for electronic recoils. As a
result, the time-dependent recombination is implemented in the determination of
charge and light yield with a generic model. Our model agrees well with the
available experimental data from xenon-based dark matter experiments.


title:
Region of Attraction Estimation Using Invariant Sets and Rational
  Lyapunov Functions

abstract:
  This work addresses the problem of estimating the region of attraction (RA)
of equilibrium points of nonlinear dynamical systems. The estimates we provide
are given by positively invariant sets which are not necessarily defined by
level sets of a Lyapunov function. Moreover, we present conditions for the
existence of Lyapunov functions linked to the positively invariant set
formulation we propose. Connections to fundamental results on estimates of the
RA are presented and support the search of Lyapunov functions of a rational
nature. We then restrict our attention to systems governed by polynomial vector
fields and provide an algorithm that is guaranteed to enlarge the estimate of
the RA at each iteration.


title:
Evolution operators in conformal field theories and conformal mappings:
  the entanglement Hamiltonian, the sine-square deformation, and others

abstract:
  By making use of conformal mapping, we construct various time-evolution
operators in (1+1) dimensional conformal field theories (CFTs), which take the
form $\int dx\, f(x) \mathcal{H}(x)$, where $\mathcal{H}(x)$ is the Hamiltonian
density of the CFT, and $f(x)$ is an envelope function. Examples of such
deformed evolution operators include the entanglement Hamiltonian, and the
so-called sine-square deformation of the CFT. Within our construction, the
spectrum and the (finite-size) scaling of the level spacing of the deformed
evolution operator are known exactly. Based on our construction, we also
propose a regularized version of the sine-square deformation, which, in
contrast to the original sine-square deformation, has the spectrum of the CFT
defined on a spatial circle of finite circumference $L$, and for which the
level spacing scales as $1/L^2$, once the circumference of the circle and the
regularization parameter are suitably adjusted.


title:
Reflected light from giant planets in habitable zones: Tapping into the
  power of the Cross-Correlation Function

abstract:
  The direct detection of reflected light from exoplanets is an excellent probe
for the characterization of their atmospheres. The greatest challenge for this
task is the low planet-to-star flux ratio, which even in the most favourable
case is of the order of $10^{-4}$ in the optical. This ratio decreases even
more for planets in their host habitable zone, typically lower than $10^{-7}$.
To reach the signal-to-noise level required for such detections, we propose to
unleash the power of the Cross Correlation Function in combination with the
collecting power of next generation observing facilities. The technique we
propose has already yielded positive results by detecting the reflected
spectral signature of 51 Pegasi b (see Martins et al. 2015). In this work, we
attempted to infer the number of hours required for the detection of several
planets in their host habitable zone using the aforementioned technique from
theoretical EELT observations. Our results show that for 5 of the selected
planets it should be possible to directly recover their reflected spectral
signature.


title: The Quantum Logic of Direct-Sum Decompositions

abstract:
  Since the pioneering work of Birkhoff and von Neumann, quantum logic has been
interpreted as the logic of (closed) subspaces of a Hilbert space. There is a
progression from the usual Boolean logic of subsets to the "quantum logic" of
subspaces of a general vector space--which is then specialized to the closed
subspaces of a Hilbert space. But there is a "dual" progression. The notion of
a partition (or quotient set or equivalence relation) is dual (in a
category-theoretic sense) to the notion of a subset. Hence the Boolean logic of
subsets has a dual logic of partitions. Then the dual progression is from that
logic of partitions to the quantum logic of direct-sum decompositions (i.e.,
the vector space version of a set partition) of a general vector space--which
can then be specialized to the direct-sum decompositions of a Hilbert space.
This allows the logic to express measurement by any self-adjoint operators
rather than just the projection operators associated with subspaces. In this
introductory paper, the focus is on the quantum logic of direct-sum
decompositions of a finite-dimensional vector space (including such a Hilbert
space). The primary special case examined is finite vector spaces over 2 where
the pedagogical model of quantum mechanics over sets (QM/Sets) is formulated.
In the Appendix, the combinatorics of direct-sum decompositions of finite
vector spaces over GF(q) is analyzed with computations for the case of QM/Sets
where q=2.


title:
Optimal Parameter Settings for the $(1+(\lambda, \lambda))$ Genetic
  Algorithm

abstract:
  The $(1+(\lambda,\lambda))$ genetic algorithm is one of the few algorithms
for which a super-constant speed-up through the use of crossover could be
proven. So far, this algorithm has been used with parameters based also on
intuitive considerations. In this work, we rigorously regard the whole
parameter space and show that the asymptotic time complexity proven by Doerr
and Doerr (GECCO 2015) for the intuitive choice is best possible among all
settings for population size, mutation probability, and crossover bias.


title:
Weighted information and weighted entropic inequalities for qutrit and
  ququart states

abstract:
  The notion of weighted quantum entropy is reviewed and considered for
bipartite and noncomposite quantum systems. The known for the weighted entropy
information inequality (subadditivity condition) is extended to the case of
indivisible qudit system on example of qutrit. This new inequality for qutrit
density matrix is discussed for different cases of weights and states. The role
of weighted entropy is discussed in connection with studies of nonlinear
quantum channels.


title: Mixing sets for non-mixing transformations

abstract:
  For different classes of measure preserving transformations, we investigate
collections of sets that exhibit the property of lightly mixing. Lightly mixing
is a stronger property than topological mixing, and requires that a lim inf is
positive. In particular, we give a straightforward proof that any mildly mixing
transformation T has a dense algebra C such that T is lightly mixing on C.
Also, we provide a hierarchy for the properties of lightly mixing, sweeping out
and uniform sweeping out for dense collections, and dense algebras of sets. As
a result, stronger mixing realizations are given for several types of
transformations than those given by previous extensions of the Jewett-Krieger
Theorem.


title: Efficient Reallocation under Additive and Responsive Preferences

abstract:
  Reallocating resources to get mutually beneficial outcomes is a fundamental
problem in various multi-agent settings. While finding an arbitrary Pareto
optimal allocation is generally easy, checking whether a particular allocation
is Pareto optimal can be much more difficult. This problem is equivalent to
checking that the allocated objects cannot be reallocated in such a way that at
least one agent prefers her new share to his old one, and no agent prefers her
old share to her new one. We consider the problem for two related types of
preference relations over sets of objects. In the first part of the paper we
focus on the setting in which agents express additive cardinal utilities over
objects. We present computational hardness results as well as polynomial-time
algorithms for testing Pareto optimality under different restrictions such as
two utility values or lexicographic utilities. In the second part of the paper
we assume that agents express only their (ordinal) preferences over single
objects, and that their preferences are additively separable. In this setting,
we present characterizations and polynomial-time algorithms for possible and
necessary Pareto optimality.


title: Integral and asymptotic properties of solitary waves in deep water

abstract:
  We consider two- and three-dimensional gravity and gravity-capillary solitary
water waves in infinite depth. Assuming algebraic decay rates for the free
surface and velocity potential, we show that the velocity potential necessarily
behaves like a dipole at infinity and obtain a related asymptotic formula for
the free surface. We then prove an identity relating the "dipole moment" to the
kinetic energy. This implies that the leading-order terms in the asymptotics
are nonvanishing and in particular that the angular momentum is infinite.
Lastly we prove a related integral identity which rules out waves of pure
elevation or pure depression.


title:
BundleFusion: Real-time Globally Consistent 3D Reconstruction using
  On-the-fly Surface Re-integration

abstract:
  Real-time, high-quality, 3D scanning of large-scale scenes is key to mixed
reality and robotic applications. However, scalability brings challenges of
drift in pose estimation, introducing significant errors in the accumulated
model. Approaches often require hours of offline processing to globally correct
model errors. Recent online methods demonstrate compelling results, but suffer
from: (1) needing minutes to perform online correction preventing true
real-time use; (2) brittle frame-to-frame (or frame-to-model) pose estimation
resulting in many tracking failures; or (3) supporting only unstructured
point-based representations, which limit scan quality and applicability. We
systematically address these issues with a novel, real-time, end-to-end
reconstruction framework. At its core is a robust pose estimation strategy,
optimizing per frame for a global set of camera poses by considering the
complete history of RGB-D input with an efficient hierarchical approach. We
remove the heavy reliance on temporal tracking, and continually localize to the
globally optimized frames instead. We contribute a parallelizable optimization
framework, which employs correspondences based on sparse features and dense
geometric and photometric matching. Our approach estimates globally optimized
(i.e., bundle adjusted) poses in real-time, supports robust tracking with
recovery from gross tracking failures (i.e., relocalization), and re-estimates
the 3D model in real-time to ensure global consistency; all within a single
framework. Our approach outperforms state-of-the-art online systems with
quality on par to offline methods, but with unprecedented speed and scan
completeness. Our framework leads to a comprehensive online scanning solution
for large indoor environments, enabling ease of use and high-quality results.


title: Solar water splitting: efficiency discussion

abstract:
  The current state of the art in direct water splitting in
photo-electrochemical cells (PECs) is presented together with: (i) a case study
of water splitting using a simple solar cell with the most efficient water
splitting electrodes and (ii) a detailed mechanism analysis. Detailed analysis
of the energy balance and efficiency of solar hydrogen production are
presented. The role of hydrogen peroxide formation as an intermediate in oxygen
evolution reaction is newly revealed and explains why an oxygen evolution is
not taking place at the thermodynamically expected 1.23 V potential.
  Solar hydrogen production with electrical-to-hydrogen conversion efficiency
of 52% is demonstrated using a simple ~0.7%-efficient n-Si/Ni Schottky solar
cell connected to a water electrolysis cell. This case study shows that
separation of the processes of solar harvesting and electrolysis avoids
photo-electrode corrosion and utilizes optimal electrodes for hydrogen and
oxygen evolution reactions and achieves ~10% efficiency in light-to-hydrogen
conversion with a standard 18% efficient household roof Si-solar cells.


title:
Exact diagonalization of the $d-$dimensional confined quantum harmonic
  oscillator

abstract:
  In the existing literature various numerical techniques have been developed
to quantize the confined harmonic oscillator in higher dimensions. In obtaining
the energy eigenvalues, such methods often involve indirect approaches such as
searching for the roots of hypergeometric functions or numerically solving a
differential equation. In this paper, however, we derive an explicit matrix
representation for the Hamiltonian of a confined quantum harmonic oscillator in
higher dimensions, thus facilitating direct diagonalization.


title:
SOAR optical and near-infrared spectroscopic survey of newly discovered
  massive stars in the periphery of Galactic Massive star clusters I - NGC3603

abstract:
  In this work, we present a spectroscopic study of very massive stars found
outside the center of the massive stellar cluster NGC3603. From the analysis of
SOAR spectroscopic data and related optical-NIR photometry, we confirm the
existence of several very massive stars in the periphery of NGC 3603. The first
group of objects (MTT58, WR42e and RFS7) is compound by three new Galactic
exemplars of the OIf*/WN type, all of them with probable initial masses well
above 100 Msun and estimated ages of about 1 Myr. Based on Goodman blue-optical
spectrum of MTT68, we can confirm the previous finding in the NIR of the only
other Galactic exemplar (besides HD93129A) of the O2If* type known to date.
Based on its position relative to a set of theoretical isochrons in a
Hertzprung-Russel diagram, we concluded that the new O2If* star could be one of
the most massive (150 Msun) and luminous (Mv=-7.3) O-star in the Galaxy. Also,
another remarkable result is the discovery of a new O2V star (MTT31) that is
the first exemplar of the class so far identified in the Milk Way. From its
position in the Hertzprung-Russel diagram it is found that this new star
probably had an initial mass of 80 Msun, as well as an absolute magnitude
Mv=-6.0 corresponding to a luminosity similar to other known O2V stars in the
LMC. We also communicate the discovery of a new Galactic O3.5If* star (RFS8)
which case is quite intriguing. Indeed, It is located far to the south of the
NGC 3603 center, in apparent isolation at a large radial projected linear
distance of 62 pc. Its derived luminosity is similar to that of the other
O3.5If* (Sh18) found in the NGC 3603's innermost region. The fact that a such
high mass star is observed far isolated in the field led us to speculate that
perhaps it could have been expelled from the innermost parts of the complex by
a close fly-by dynamical encounter with a very massive hard binary system.


title: A Dispersion Minimized Mimetic Method for Cold Plasma

abstract:
  In this paper we consider the lowest edge-based mimetic finite difference
(MFD) discretization in space for Maxwell's equations in cold plasma on
rectangular meshes. The method uses a generalized form of mass lumping that, on
one hand, eliminates a need for linear solves at every iteration while, on the
other hand, retains a set of free parameters of the MFD discretization. We
perform an optimization procedure, called m-adaptation, that identified a set
of free parameters that lead to the smallest numerical dispersion. The choice
of the time stepping proved to be critical for successful optimization. Using
exponential time differencing we were able to reduce the numerical dispersion
error from second to fourth order of accuracy in mesh size. It was not possible
to achieve this order of magnitude reduction in numerical dispersion error
using the standard leapfrog time stepping. Numerical simulations independently
verify our theoretical findings.


title:
Influence of coalescence parameters on the production of protons and
  Helium-3 fragments

abstract:
  The time evolution of protons and $^3$He fragments from Au+Au/Pb+Pb reactions
at 0.25, 2, and 20 GeV$/$nucleon is investigated with the potential version of
the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) model combined with
the traditional coalescence afterburner. In the coalescence process, the
relative distance $R_0$ and relative momentum $P_0$ are surveyed in the range
of 3-4 fm and 0.25-0.35 GeV$/$c, respectively. For both clusters, a strong
reversed correlation between $R_0$ and $P_0$ is seen and it is time-dependent
as well. For protons, the accepted ($R_0$, $P_0$) bands lie in the time
interval 30-60 fm$/$c, while for $^3$He, a longer time evolution (at about
60-90 fm$/$c) is needed. Otherwise, much smaller $R_0$ and $P_0$ values should
be chosen. If we further look at the rapidity distributions from both central
and semi-central collisions, it is found that the accepted [$t_{\rm cut}, (R_0,
P_0$)] assemble can provide consistent results for proton yield and collective
flows especially at mid-rapdities, while for $^3$He, the consistency is
destroyed at both middle and projectile-target rapidities.


title:
A new estimator of the deceleration parameter from galaxy rotation
  curves

abstract:
  The nature of dark energy may be probed by the derivative
$Q=\left.dq(z)/dz\right|_0$ at redshift $z=0$ of the deceleration parameter
$q(z)$. It is probably static if $Q<1$ or dynamic if $Q>2.5$, supporting
$\Lambda$CDM or, respectively, $\Lambda=(1-q)H^2$, where $H$ denotes the Hubble
parameter. We derive $q=1-\left(4\pi a_0/cH\right)^{2}$, enabling a
determination of $q(z)$ by measurement of Milgrom's parameter $a_0(z)$ in
galaxy rotation curves, equivalent to the coefficient $A$ in the Tully-Fisher
relation $V^4_c=AM_b$ between rotation velocity $V_c$ and baryonic mass $M_b$.
We infer that dark matter should be extremely light with clustering limited to
the size of galaxy clusters. The associated transition radius to non-Newtonian
gravity may conceivably be probed in a free fall Cavendish type experiment in
space.