title:
Modulated magnetism and anomalous electronic transport in $\rm
  Ce_3Cu_4As_4O_2$

abstract:
  The complex magnetism and transport properties of tetragonal
Ce$_3$Cu$_4$As$_4$O$_2$ were examined through neutron scattering and physical
properties measurements on polycrystalline samples. The lamellar structure
consists of alternating layers of $\rm CeCu_4As_4$ with a single square Ce
lattice and oxygen-linked Ce bi-layer $\rm Ce_2O_2$. Extending along $\bf c$, a
tube-like Fermi surface from DFT calculations points to a quasi-two-dimensional
electronic system. Peaks in the specific heat at the Ne\'{e}l temperature
$T_{N}=24$ $\rm K$, $T_{2}~=~16 $ $\rm K$ and $T_{3}~=~1.9$ $ \rm K$ indicate
three magnetic phase transitions or distinct cross-over phenomena. For
$T<T_{N}$ neutron diffraction indicates the development of ferromagnetic ab
sheets for both Ce sites, with alternating polarization along $\bf{c}$, a wave
vector ${\bf k}_{1}={\bf c}^*$. For $T<T_{2}$, quasi-two-dimensional low-energy
spin fluctuations with ${\bf k}_{2}=\frac{1}{2}{\bf a}^*$ and polarized
perpendicular to ${\bf k}_{2}$ are suppressed. The data are consistent with
quasi-two-dimensional antiferromagnetic order in the $\rm CeCu_4As_4$ planes
polarized along the ${\bf k}_{2}$ wave vector. $T_{3}$ marks a spin-flop
transition where the ${\bf k}_{1}$ staggered magnetization switches to in-plane
polarization. While the narrow 4f bands lie deep below the Fermi surface, there
are significant transport anomalies associated with the transitions; in
particular a substantial reduction in resistivity for $T<T_{N}$. At $T=100$ $
\rm mK$ the ${\bf k}_1$ modulated staggered moment is $0.85~\mu_B$, which
matches the $0.8~\mu_B$ saturation magnetization achieved for H $~=~7$ $ \rm T$
at $T~=~2$ $ \rm K$. From low T Lorentzian fits the correlation length is in
excess of 75 \AA. We argue the unusual sequence of magnetic transitions results
from competing interactions and anisotropies for the two Ce sites.


title: Two double poset polytopes

abstract:
  To every poset P, Stanley (1986) associated two polytopes, the order polytope
and the chain polytope, whose geometric properties reflect the combinatorial
qualities of P. This construction allows for deep insights into combinatorics
by way of geometry and vice versa. Malvenuto and Reutenauer (2011) introduced
'double posets', that is, (finite) sets equipped with two partial orders, as a
generalization of Stanley's labelled posets. Many combinatorial constructions
can be naturally phrased in terms of double posets. We introduce the 'double
order polytope' and the 'double chain polytope' and we amply demonstrate that
they geometrically capture double posets, i.e., the interaction between the two
partial orders. We describe the facial structures, Ehrhart polynomials, and
volumes of these polytopes in terms of the combinatorics of double posets. We
also describe a curious connection to Geissinger's valuation polytopes and we
characterize 2-level polytopes among our double poset polytopes.
  Fulkerson's 'anti-blocking' polytopes from combinatorial optimization subsume
stable set polytopes of graphs and chain polytopes of posets. We determine the
geometry of Minkowski- and Cayley sums of anti-blocking polytopes. In
particular, we describe a canonical subdivision of Minkowski sums of
anti-blocking polytopes that facilitates the computation of Ehrhart
(quasi-)polynomials and volumes. This also yields canonical triangulations of
double poset polytopes.
  Finally, we investigate the affine semigroup rings associated to double poset
polytopes. We show that they have quadratic Groebner bases, which gives an
algebraic description of the unimodular flag triangulations described in the
first part.


title: Landau's Nobel Prize in Physics

abstract:
  Work of Lev Landau had a profound impact on the physics in 20th century.
Landau had created the paradigms that had framed the conversations on the
outstanding problems in physics for decades. He has laid the foundations for
our understanding of quantum matter such as superfluidity, superconductivity
and the theory of Fermi Liquid. Here we present sampled Nobel Archive data on
the winning nomination that led to the Nobel Prize in Physics in 1962.


title:
A practical local tomography reconstruction algorithm based on known
  subregion

abstract:
  We propose a new method to reconstruct data acquired in a local tomography
setup. This method uses an initial reconstruction and refines it by correcting
the low frequency artifacts known as the cupping effect. A basis of Gaussian
functions is used to correct the initial reconstruction. The coefficients of
this basis are iteratively optimized under the constraint of a known subregion.
Using a coarse basis reduces the degrees of freedom of the problem while
actually correcting the cupping effect. Simulations show that the known region
constraint yields an unbiased reconstruction, in accordance to uniqueness
theorems stated in local tomography.


title:
Suzaku Observations of Moderately Obscured (Compton-thin) Active
  Galactic Nuclei Selected by Swift/BAT Hard X-ray Survey

abstract:
  We report the results obtained by a systematic, broadband (0.5--150 keV)
X-ray spectral analysis of moderately obscured (Compton-thin; $22 \leq \log
N_{\rm H} < 24$) active galactic nuclei (AGNs) observed with Suzaku and
Swift/Burst Alert Telescope (BAT). Our sample consists of 45 local AGNs at
$z<0.1$ with $\log L_{\rm 14-195\1mmkeV} > 42$ detected in the Swift/BAT
70-month survey, whose Suzaku archival data are available as of 2015 December.
All spectra are uniformly fit with a baseline model composed of an absorbed
cutoff power-law component, reflected emission accompanied by a narrow
fluorescent iron-K$\alpha$ line from cold matter (torus), and scattered
emission. Main results based on the above analysis are as follows. (1) The
photon index is correlated with Eddington ratio, but not with luminosity or
black hole mass. (2) The ratio of the iron-K$\alpha$ line to X-ray luminosity,
a torus covering fraction indicator, shows significant anti-correlation with
luminosity. (3) The averaged reflection strength derived from stacked spectra
above 14 keV is larger in less luminous ($\log L_{\rm 10-50\1mmkeV} \leq 43.3$;
$R= 1.04^{+0.17}_{-0.19}$) or highly obscured AGNs ($\log N_{\rm H} > 23$; $R =
1.03^{+0.15}_{-0.17}$) than in more luminous ($\log L_{\rm 10-50\1mmkeV} >
43.3$; $R= 0.46^{+0.08}_{-0.09}$) or lightly obscured objects ($\log N_{\rm H}
\leq 23$; $R = 0.59^{+0.09}_{-0.10}$), respectively. (4) The [O IV] 25.89
$\mu$m line to X-ray luminosity ratio is significantly smaller in AGNs with
lower soft X-ray scattering fractions, suggesting that the [O IV] 25.89 $\mu$m
luminosity underestimates the intrinsic power of an AGN buried in a small
opening-angle torus.


title: Simulating disk galaxies and interactions in Milgromian dynamics

abstract:
  Since its publication 1983, Milgromian dynamics (aka MOND) has been very
successful in modeling the gravitational potential of galaxies from baryonic
matter alone. However, the dynamical modeling has long been an unsolved issue.
In particular, the setup of a stable galaxy for Milgromian N-body calculations
has been a major challenge. Here, we show a way to set up disc galaxies in MOND
for calculations in the PHANTOM OF RAMSES (PoR) code by L\"ughausen (2015) and
Teyssier (2002). The method is done by solving the QUMOND Poisson equations
based on a baryonic and a phantom dark matter component. The resulting galaxy
models are stable after a brief settling period for a large mass and size
range. Simulations of single galaxies as well as colliding galaxies are shown.


title: The Leptonic Higgs Portal

abstract:
  An extended Higgs sector may allow for new scalar particles well below the
weak scale. In this work, we present a detailed study of a light scalar $S$
with enhanced coupling to leptons, which could be responsible for the existing
discrepancy between experimental and theoretical determinations of the muon
anomalous magnetic moment. We present an ultraviolet completion of this model
in terms of the lepton-specific two-Higgs doublet model and an additional
scalar singlet. We then analyze a plethora of experimental constraints on the
universal low energy model, and this UV completion, along with the sensitivity
reach at future experiments. The most relevant constraints originate from muon
and kaon decays, electron beam dump experiments, electroweak precision
observables, rare $B_d$ and $B_s$ decays and Higgs branching fractions. The
properties of the leptonic Higgs portal imply an enhanced couplings to heavy
leptons, and we identify the most promising search mode for the high-luminosity
electron-positron colliders as $e^+{+}e^-\to\tau^+{+}\tau^-{+}S \to
\tau^+{+}\tau^-{+}\ell{+}\bar \ell$, where $\ell =e,\mu$. Future analyses of
existing data from BaBar and Belle, and from the upcoming Belle II experiment,
will enable tests of this model as a putative solution to the muon $g-2$
problem for $m_S < 3.5$ GeV.


title:
The entropy emission properties of near-extremal Reissner-Nordstr\"om
  black holes

abstract:
  Bekenstein and Mayo have revealed an interesting property of evaporating
$(3+1)$-dimensional Schwarzschild black holes: their entropy emission rates
$\dot S_{\text{Sch}}$ are related to their energy emission rates $P$ by the
simple relation $\dot S_{\text{Sch}}=C_{\text{Sch}}\times (P/\hbar)^{1/2}$.
Remembering that $(1+1)$-dimensional perfect black-body emitters are
characterized by the same functional relation, $\dot
S^{1+1}=C^{1+1}\times(P/\hbar)^{1/2}$, Bekenstein and Mayo have concluded that,
in their entropy emission properties, $(3+1)$-dimensional Schwarzschild black
holes behave effectively as $(1+1)$-dimensional entropy emitters. One naturally
wonders whether all black holes behave as simple $(1+1)$-dimensional entropy
emitters? In order to address this interesting question, we shall study in this
paper the entropy emission properties of Reissner-Nordstr\"om black holes. We
shall show, in particular, that the physical properties which characterize the
neutral sector of the Hawking emission spectra of these black holes can be
studied {\it analytically} in the near-extremal $T_{\text{BH}}\to0$ regime. We
find that the Hawking radiation spectra of massless neutral scalar fields and
coupled electromagnetic-gravitational fields are characterized by the
non-trivial entropy-energy relations $\dot S^{\text{Scalar}}_{\text{RN}} =
-C^{\text{Scalar}}_{\text{RN}} \times (AP^3/\hbar^3)^{1/4} \ln(AP/\hbar)$ and
$\dot S^{\text{Elec-Grav}}_{\text{RN}} = -C^{\text{Elec-Grav}}_{\text{RN}}
\times (A^4P^9/\hbar^9)^{1/10} \ln(AP/\hbar)$ in the near-extremal
$T_{\text{BH}}\to0$ limit (here $A$ is the surface area of the
Reissner-Nordstr\"om black hole). Our analytical results therefore indicate
that {\it not} all black holes behave as simple $(1+1)$-dimensional entropy
emitters.


title:
Chiral kinetic theory and anomalous hydrodynamics in even spacetime
  dimensions

abstract:
  We study the hydrodynamics of a gas of noninteracting Weyl fermions coupled
to the electromagnetic field in $(2N + 1) + 1$ spacetime dimensions using the
chiral kinetic theory, which encodes the gauge anomaly in the Chern character
of the nonabelian Berry connection over the Fermi surface. We derive the
anomalous contributions to the relativistic hydrodynamic currents in
equilibrium and at a finite temperature, which agree with and provides an
approach complementary to the results derived previously using thermodynamic
constraints.


title: The number and size of subhalo-induced gaps in stellar streams

abstract:
  Ample observational capabilities exist today to detect the small density
perturbations that low-mass dark matter subhaloes impart on stellar streams
from disrupting Galactic satellites. In anticipation of these observations, we
investigate the expected number and size of gaps by combining an analytic
prescription for gap evolution on circular orbits with the flux of subhaloes
near the stream. We explore the distribution of gap sizes and depths for a
typical cold stream around the Milky Way and find that for a given stream age
and gap depth, each subhalo mass produces a characteristic gap size. For a
stream with an age of a few Gyr, orbiting at a distance of 10-20 kpc from the
Galactic center, even modest subhaloes with a mass of $10^6-10^7 M_\odot$
produce gaps with sizes that are on the order of several degrees. We consider
the number and distribution of gap sizes created by subhaloes with masses
$10^5-10^9 M_\odot$, accounting for the expected depletion of subhaloes by the
Milky Way disk, and present predictions for six cold streams around the Milky
Way. For Pal 5, we forecast 0.7 gaps with a density depletion of at least 25\%
and a typical gap size of $8^\circ$. Thus, there appears to be {\it no tension}
between the recent non-detection of density depletions in the Pal 5 tidal tails
and $\Lambda$CDM expectations. These predictions can be used to guide the scale
of future gap searches.


title:
Models of low-mass helium white dwarfs including gravitational settling,
  thermal and chemical diffusion, and rotational mixing

abstract:
  A large number of extremely low-mass helium white dwarfs (ELM WDs) have been
discovered in recent years. The majority of them are found in close binary
systems suggesting they are formed either through a common-envelope phase or
via stable mass transfer in a low-mass X-ray binary (LMXB) or a cataclysmic
variable (CV) system. Here, we investigate the formation of these objects
through the LMXB channel with emphasis on the proto-WD evolution in
environments with different metallicities. We study, for the first time, the
combined effects of rotational mixing and element diffusion (e.g. gravitational
settling, thermal and chemical diffusion) on the evolution of proto-WDs and on
the cooling properties of the resulting WDs. We present state-of-the-art binary
stellar evolution models computed with MESA for metallicities between Z=0.0002
and Z=0.02, producing WDs with masses between 0.16-0.45 M$_{\odot}$. Our
results confirm that element diffusion plays a significant role in the
evolution of proto-WDs that experience hydrogen shell flashes. The occurrence
of these flashes produces a clear dichotomy in the cooling timescales of ELM
WDs, which has important consequences e.g. for the age determination of binary
millisecond pulsars. Rotational mixing is found to counteract the effect of
gravitational settling in the surface layers of young, bloated ELM proto-WDs
and therefore plays a key role in determining their surface chemical
abundances. We predict that these proto-WDs have helium-rich envelopes through
a significant part of their lifetime, a crucial ingredient for understanding
the newly observed ELM proto-WD pulsators. The hydrogen envelope at detachment,
although small compared to the total mass of the WD, contains enough angular
momentum such that the spin frequency of the resulting WD on the cooling track
is well above the orbital frequency.


title: Supergravity from D0-brane Quantum Mechanics

abstract:
  The gauge/gravity duality conjecture claims the equivalence between gauge
theory and superstring/M-theory. In particular, the one-dimensional gauge
theory of D0-branes and type IIA string theory should agree on properties of
hot black holes. Type IIA superstring theory predicts the leading $N^2$
behavior of the black hole internal energy to be $E/N^2=a_0T^{14/5}+
a_1T^{23/5}+a_2T^{29/5}+\cdots$ with the supergravity prediction $a_0=7.41$ and
unknown coefficients $a_1$, $a_2$, $\ldots$ associated with stringy
corrections. In order to test this duality we perform a lattice study of the
gauge theory and extract a continuum, large-$N$ value of $a_0=7.4\pm 0.5$---the
first direct confirmation of the supergravity prediction at finite
temperature---and constrain the stringy corrections ($a_1=-9.7\pm2.2$ and
$a_2=5.6\pm1.8$). We also study the sub-leading $1/N^2$ corrections to the
internal energy.


title:
New Insights into Properties of Large-N Holographic Thermal QCD at
  Finite Gauge Coupling at (the Non-Conformal/Next-to) Leading Order in N

abstract:
  In the context of [1]'s string theoretic dual of large-N thermal QCD-like
theories at finite gauge/string coupling (as part of the `MQGP' limit of [2]),
we discuss the following. First, up to LO in N, using the results of [3], we
show that the local T^3 of [2] is the T^2-invariant sLag of [3] in a resolved
conifold. This, together with the results of [4], shows that for a
(predominantly resolved or deformed) resolved warped deformed conifold, the
local T^3 of [2] in the MQGP limit, is the T^2-invariant sLag of [3] justifying
the construction of the delocalized SYZ type IIA mirror of the type IIB
background of [1]. Then, using the prescription of [5], we obtain the
temperature dependence of the thermal (and electrical) conductivity working up
to leading order in N (the number of D3-branes), and upon comparison with [6]
show that the results mimic a 1+1-dimensional Luttinger liquid with impurities.
Further, including sub-leading non-conformal terms in the metric determined by
M (the number of fractional D-branes = the number of colors = 3 in the IR after
the end of a Seiberg duality cascade), by looking at respectively the scalar,
vector and tensor modes of metric perturbations and using [7]'s prescription of
constructing appropriate gauge-invariant perturbations, we obtain respectively
the speed of sound, the diffusion constant and the shear viscosity \eta (and
\eta/s) including the non-conformal O((g_s M^2) (g_s N_f)/N<<1)-corrections,
N_f being the number of flavor D7-branes.


title: Electrons at the monkey saddle: a multicritical Lifshitz point

abstract:
  We consider 2D interacting electrons at a monkey saddle with dispersion
$\propto p_x^3-3p_xp_y^2$. Such a dispersion naturally arises at the
multicritical Lifshitz point when three van Hove saddles merge in an elliptical
umbilic elementary catastrophe, which we show can be realized in biased bilayer
graphene. A multicritical Lifshitz point of this kind can be identified by its
signature Landau level behavior $E_m\propto (Bm)^{3/2}$ and related
oscillations in thermodynamic and transport properties, such as de Haas-van
Alphen and Shubnikov-de Haas oscillations, whose period triples as the system
crosses the singularity. We show, in the case of a single monkey saddle, that
the non-interacting electron fixed point is unstable to interactions under the
renormalization group flow, developing either a superconducting instability or
non-Fermi liquid features. Biased bilayer graphene, where there are two
non-nested monkey saddles at the $K$ and $K^\prime$ points, exhibits an
interplay of competing many-body instabilities, namely s-wave
superconductivity, ferromagnetism, and spin- and charge-density wave.


title: Precision lattice test of the gauge/gravity duality at large-$N$

abstract:
  We pioneer a systematic, large-scale lattice simulation of D0-brane quantum
mechanics. The large-$N$ and continuum limits of the gauge theory are taken for
the first time at various temperatures $0.4 \leq T \leq 1.0$. As a way to
directly test the gauge/gravity duality conjecture we compute the internal
energy of the black hole directly from the gauge theory and reproduce the
coefficient of the supergravity result $E/N^2=7.41T^{14/5}$. This is the first
confirmation of the supergravity prediction for the internal energy of a black
hole at finite temperature coming directly from the dual gauge theory. We also
constrain stringy corrections to the internal energy.


title:
Mass assembly and morphological transformations since $z\sim3$ from
  CANDELS

abstract:
  [abridged] We quantify the evolution of the stellar mass functions of
star-forming and quiescent galaxies as a function of morphology from $z\sim 3$
to the present. Our sample consists of ~50,000 galaxies in the CANDELS fields
($\sim880$ $arcmin^2$), which we divide into four main morphological types,
i.e. pure bulge dominated systems, pure spiral disk dominated, intermediate
2-component bulge+disk systems and irregular disturbed galaxies. Our main
results are:
  Star-formation: At $z\sim 2$, 80\% of the stellar mass density of
star-forming galaxies is in irregular systems. However, by $z\sim 0.5$,
irregular objects only dominate at stellar masses below $10^9M\odot$. A
majority of the star-forming irregulars present at $z\sim 2$ undergo a gradual
transformation from disturbed to normal spiral disk morphologies by $z\sim 1$
without significant interruption to their star-formation. Rejuvenation after a
quenching event does not seem to be common except perhaps for the most massive
objects.
  Quenching: We confirm that galaxies reaching a stellar mass of
$M_*\sim10^{10.8}M_\odot$ ($M^*$) tend to quench. Also, quenching implies the
presence of a bulge: the abundance of massive red disks is negligible at all
redshifts over 2~dex in stellar mass. However the dominant quenching mechanism
evolves. At $z>2$, the SMF of quiescent galaxies above $M^*$ is dominated by
compact spheroids. Quenching at this early epoch destroys the disk and produces
a compact remnant unless the star-forming progenitors at even higher redshifts
are significantly more dense. At $1<z<2$, the majority of newly quenched
galaxies are disks with a significant central bulge. This suggests that
mass-quenching at this epoch starts from the inner parts and preserves the
disk. At $z<1$, the high mass end of the passive SMF is globally in place and
the evolution mostly happens at stellar masses below $10^{10}M_\odot$.


title:
A Novel Approach to Fine-Tuned Supersymmetric Standard Models -- Case of
  Non-Universal Higgs Masses model

abstract:
  Discarding the prejudice about fine tuning, we propose a novel and efficient
approach to identify relevant regions of fundamental parameter space in
supersymmetric models with some amount of fine tuning. The essential idea is
the mapping of experimental constraints at a low energy scale, rather than the
parameter sets, to those of the fundamental parameter space. Applying this
method to the non-universal Higgs masses model, we identify a new interesting
superparticle mass pattern where some of the first two generation squarks are
light whilst the stops are kept heavy as 6TeV. Furthermore, as another
application of this method, we show that the discrepancy of the muon anomalous
magnetic dipole moment can be filled by a supersymmetric contribution within
the 1 {\sigma} level of the experimental and theoretical errors, which was
overlooked by the previous studies due to the required terrible fine tuning.


title:
Insights into the location and dynamics of the coolest X-ray emitting
  gas in clusters of galaxies

abstract:
  We extend our previous study of the cool gas responsible for the emission of
OVII X-ray lines in the cores of clusters and groups of galaxies. This is the
coolest X-ray emitting phase and connects the 10,000 K H {\alpha} emitting gas
to the million degree phase, providing a useful tool to understand cooling in
these objects. We study the location of the O VII gas and its connection to the
intermediate Fe XVII and hotter O VIII phases. We use high-resolution X-ray
grating spectra of elliptical galaxies with strong Fe XVII line emission and
detect O VII in 11 of 24 objects. Comparing the O VII detection level and
resonant scattering, which is sensitive to turbulence and temperature, suggests
that OVII is preferably found in cooler objects, where the FeXVII resonant line
is suppressed due to resonant scattering, indicating subsonic turbulence.
Although a larger sample of sources and further observations is needed to
distinguish between effects from temperature and turbulence, our results are
consistent with cooling being suppressed at high turbulence as predicted by
models of AGN feedback, gas sloshing and galactic mergers. In some objects the
OVII resonant-to-forbidden line ratio is decreased by either resonant
scattering or charge-exchange boosting the forbidden line, as we show for NGC
4636. Charge-exchange indicates interaction between neutral and ionized gas
phases. The Perseus cluster also shows a high Fe XVII forbidden-to- resonance
line ratio, which can be explained with resonant scattering by low-turbulence
cool gas in the line-of-sight.


title: The detection and X-ray view of the changing look AGN HE 1136-2304

abstract:
  We report the detection of high-amplitude X-ray flaring of the AGN HE
1136-2304, which is accompanied by a strong increase in the flux of the broad
Balmer lines, changing its Seyfert type from almost type 2 in 1993 down to 1.5
in 2014. HE 1136-2304 was detected by the XMM-Newton slew survey at >10 times
the flux it had in the ROSAT all-sky survey, and confirmed with Swift follow-up
after increasing in X-ray flux by a factor of 30. Optical spectroscopy with
SALT shows that the AGN has changed from a Seyfert 1.95 to a Seyfert 1.5
galaxy, with greatly increased broad line emission and an increase in blue
continuum AGN flux by a factor of > 4. The X-ray spectra from XMM-Newton and
NuSTAR reveal moderate intrinsic absorption and a high energy cutoff at 100
keV. We consider several different physical scenarios for a flare, such as
changes in obscuring material, tidal disruption events, and an increase in the
accretion rate. We find that the most likely cause of the increased flux is an
increase in the accretion rate, although it could also be due to a change in
obscuration.


title: Assessing Human Error Against a Benchmark of Perfection

abstract:
  An increasing number of domains are providing us with detailed trace data on
human decisions in settings where we can evaluate the quality of these
decisions via an algorithm. Motivated by this development, an emerging line of
work has begun to consider whether we can characterize and predict the kinds of
decisions where people are likely to make errors.
  To investigate what a general framework for human error prediction might look
like, we focus on a model system with a rich history in the behavioral
sciences: the decisions made by chess players as they select moves in a game.
We carry out our analysis at a large scale, employing datasets with several
million recorded games, and using chess tablebases to acquire a form of ground
truth for a subset of chess positions that have been completely solved by
computers but remain challenging even for the best players in the world.
  We organize our analysis around three categories of features that we argue
are present in most settings where the analysis of human error is applicable:
the skill of the decision-maker, the time available to make the decision, and
the inherent difficulty of the decision. We identify rich structure in all
three of these categories of features, and find strong evidence that in our
domain, features describing the inherent difficulty of an instance are
significantly more powerful than features based on skill or time.


title:
Theorem: A Static Magnetic N-pole Becomes an Oscillating Electric N-pole
  in a Cosmic Axion Field

abstract:
  We show for the classical Maxwell equations, including the axion
electromagnetic anomaly source term, that a cosmic axion field induces an
oscillating electric N-moment for any static magnetic N-moment. This is a
straightforward result, accessible to anyone who has taken a first year
graduate course in electrodynamics.


title: Vacuum Energy Sequestering and Graviton Loops

abstract:
  We recently formulated a local mechanism of vacuum energy sequester. This
mechanism automatically removes all matter loop contributions to vacuum energy
from the stress energy tensor which sources the curvature. Here we adapt the
local vacuum energy sequestering mechanism to also cancel all the vacuum energy
loops involving virtual gravitons, in addition to the vacuum energy generated
by matter fields alone.


title: Multiple Outflows in the Giant Eruption of a Massive Star

abstract:
  The supernova impostor PSN J09132750+7627410 in NGC 2748 reached a maximum
luminosity of approximately -14 mag. It was quickly realized that its was not a
true supernova, but another example of a non-terminal giant eruption. PSN
J09132750+7627410 is distinguished by multiple P Cygni absorption minima in the
Balmer emission lines that correspond to outflow velocities of -400, -1100, and
-1600 km/s. Multiple outflows have been observed in only a few other objects.
In this paper we describe the evolution of the spectrum and the P Cygni
profiles for three months past maximum, the post-maximum formation of a cool,
dense wind, and the identification of a possible progenitor. One of the
possible progenitors is an infrared source. Its pre-eruption spectral energy
distribution suggests a bolometric luminosity of -8.3 mag and a dust
temperature of 780 degrees K. If it is the progenitor it is above the AGB limit
unlike the intermediate luminosity red transients. The three P Cygni profiles
could be due to ejecta from the current eruption, the wind of the progenitor,
or previous mass loss events. We suggest that they were all formed as part of
the same high mass loss event and are due to material ejected at different
velocities or energies. We also suggest that multiple outflows during giant
eruptions may be more common than reported.


title: Signaling equilibria for dynamic LQG games with asymmetric information

abstract:
  We consider a finite horizon dynamic game with two players who observe their
types privately and take actions, which are publicly observed. Players' types
evolve as independent, controlled linear Gaussian processes and players incur
quadratic instantaneous costs. This forms a dynamic linear quadratic Gaussian
(LQG) game with asymmetric information. We show that under certain conditions,
players' strategies that are linear in their private types, together with
Gaussian beliefs form a perfect Bayesian equilibrium (PBE) of the game.
Furthermore, it is shown that this is a signaling equilibrium due to the fact
that future beliefs on players' types are affected by the equilibrium
strategies. We provide a backward-forward algorithm to find the PBE. Each step
of the backward algorithm reduces to solving an algebraic matrix equation for
every possible realization of the state estimate covariance matrix. The forward
algorithm consists of Kalman filter recursions, where state estimate covariance
matrices depend on equilibrium strategies.


title: A new tagger for hadronically decaying heavy particles at the LHC

abstract:
  A new algorithm for the identification of boosted, hadronically decaying,
heavy particles at the LHC is presented. The algorithm is based on the known
procedure of jet clustering with variable distance parameter $R$ and adapts the
jet size to its transverse momentum $p_T$. Subjets are found using a mass jump
condition. The resulting algorithm - called Heavy Object Tagger with Variable
$R$ (HOTVR) - features little algorithmic complexity and combines jet
clustering, subjet finding and rejection of soft clusters in one sequence.
While the HOTVR algorithm can be used for the identification of any heavy
object decaying hadronically, e.g. W, Z, H, t, or possible new heavy
resonances, this paper targets specifically the tagging of boosted top quarks.
The studies presented here demonstrate a stable performance of the HOTVR
algorithm in a wide range of top quark $p_T$, from low $p_T$, where the decay
products can be resolved, to the region of boosted decays at high $p_T$.


title: Absolutely Continuous Spectrum for Parabolic Flows/Maps

abstract:
  We provide an abstract framework for the study of certain spectral properties
of parabolic systems; specifically, we determine under which general conditions
to expect the presence of absolutely continuous spectral measures. We use these
general conditions to derive results for spectral properties of time-changes of
unipotent flows on homogeneous spaces of semisimple groups regarding absolutely
continuous spectrum as well as maximal spectral type; the time-changes of the
horocycle flow are special cases of this general category of flows. In addition
we use the general conditions to derive spectral results for twisted horocycle
flows and to rederive certain spectral results for skew products over
translations and Furstenberg transformations.


title:
The Edit Distance Transducer in Action: The University of Cambridge
  English-German System at WMT16

abstract:
  This paper presents the University of Cambridge submission to WMT16.
Motivated by the complementary nature of syntactical machine translation and
neural machine translation (NMT), we exploit the synergies of Hiero and NMT in
different combination schemes. Starting out with a simple neural lattice
rescoring approach, we show that the Hiero lattices are often too narrow for
NMT ensembles. Therefore, instead of a hard restriction of the NMT search space
to the lattice, we propose to loosely couple NMT and Hiero by composition with
a modified version of the edit distance transducer. The loose combination
outperforms lattice rescoring, especially when using multiple NMT systems in an
ensemble.


title:
Veiled symmetry of disordered Parity-Time lattices: protected
  PT-threshold and the fate of localization

abstract:
  Open, non-equilibrium systems with balanced gain and loss, known as
parity-time ($\mathcal{PT}$)-symmetric systems, exhibit properties that are
absent in closed, isolated systems. A key property is the
$\mathcal{PT}$-symmetry breaking transition, which occurs when the gain-loss
strength, a measure of the openness of the system, exceeds the intrinsic
energy-scale of the system. We analyze the fate of this transition in
disordered lattices with non-Hermitian gain and loss potentials $\pm i\gamma$
at reflection-symmetric sites. Contrary to the popular belief, we show that the
$\mathcal{PT}$-symmetric phase is protected in the presence of a correlated
(periodic) disorder which leads to a positive $\mathcal{PT}$-symmetry breaking
threshold. We uncover a veiled symmetry of such disordered systems that is
instrumental for the said protection, and show that this symmetry leads to new
localization behavior across the $\mathcal{PT}$-symmetry breaking transition.
We elucidate the interplay between such localization and the
$\mathcal{PT}$-symmetry breaking phenomena in disordered
$\mathcal{PT}$-symmetric lattices, and support our conclusions with a
beam-propagation-method analysis. Our theoretical predictions provide avenues
for experimental realizations of $\mathcal{PT}$-symmetric systems with
engineered disorder.


title: Predictivity of Neutrino Mass Sum Rules

abstract:
  Correlations between light neutrino observables are arguably the strongest
predictions of lepton avour models based on (discrete) symmetries, except for
the very few cases which unambiguously predict the full set of leptonic mixing
angles. A subclass of these correlations are neutrino mass sum rules, which
connect the three (complex) light neutrino mass eigenvalues among each other.
This connection constrains both the light neutrino mass scale and the Majorana
phases, so that mass sum rules generically lead to a nonzero value of the
lightest neutrino mass and to distinct predictions for the e ective mass probed
in neutrinoless double beta decay. However, in nearly all cases known, the
neutrino mass sum rules are not exact and receive corrections from various
sources. We introduce a formalism to handle these corrections perturbatively in
a model-independent manner, which overcomes issues present in earlier
approaches. Our ansatz allows us to quantify the modi cation of the predictions
derived from neutrino mass sum rules. We show that, in most cases, the
predictions are fairly stable: while small quantitative changes can appear,
they are generally rather mild. We therefore establish the predictivity of
neutrino mass sum rules on a level far more general than previously known.


title:
C II radiative cooling of the Galactic diffuse interstellar medium:
  Insight about the star formation in Damped Lyman-alpha systems

abstract:
  The far-infrared [C II] 158 micrometer fine structure transition is
considered to be a dominant coolant in the interstellar medium. For this
reason, under the assumption of a thermal steady state, it may be used to infer
the heating rate and, in turn, the star formation rate in local, as well as in
high redshift systems. In this work, radio and ultraviolet observations of the
Galactic interstellar medium are used to understand whether C II is indeed a
good tracer of the star formation rate. For a sample of high Galactic latitude
sightlines, direct measurements of the temperature indicate the presence of C
II in both the cold and the warm phases of the diffuse interstellar gas. The
cold gas fraction (~ 10 - 50% of the total neutral gas column density) is not
negligible even at high Galactic latitude. It is shown that, to correctly
estimate the star formation rate, C II cooling in both the phases should hence
be considered. The simple assumption, that the [C II] line originates only from
either the cold or the warm phase, significantly underpredicts or overpredicts
the star formation rate, respectively. These results are particularly important
in the context of the Damped Lyman-alpha systems for which a similar method is
often used to estimate the star formation rate. The derived star formation
rates in such cases may not be reliable if the temperature of the gas under
consideration is not constrained independently.


title:
Orbifold points on Teichm\"uller curves and Jacobians with complex
  multiplication

abstract:
  For each integer $D \geq 5$ with $D \equiv 0$ or $1 \bmod 4$, the Weierstrass
curve $W_D$ is an algebraic curve and a finite volume hyperbolic orbifold which
admits an algebraic and isometric immersion into the moduli space of genus two
Riemann surfaces. The Weierstrass curves are the main examples of Teichm\"uller
curves in genus two. The primary goal of this paper is to determine the number
and type of orbifold points on each component of $W_D$. Our enumeration of the
orbifold points, together with work of Bainbridge and McMullen, completes the
determination of the homeomorphism type of $W_D$ and gives a formula for the
genus of its components. We use our formula to give bounds on the genus of
$W_D$ and determine the Weierstrass curves of genus zero. We will also give
several explicit descriptions of each surface labeled by an orbifold point on
$W_D$.


title: Symmetry and nonexistence of positive solutions for fractional systems

abstract:
  This paper is devoted to study the nonexistence results of positive solutions
for the following fractional H$\acute{e}$non system \begin{eqnarray*}\left\{
\begin{array}{lll}
  &(-\triangle)^{\alpha/2}u=|x|^av^p,~~~&x\in R^n,
  &(-\triangle)^{\alpha/2}v=|x|^bu^q,~~~ &x\in R^n,
  &u\geq0, v\geq 0,
  \end{array}
  \right. \end{eqnarray*} where $0<\alpha<2$, $0<p,q<\infty$, $a$, $b$ $\geq0$,
$n\geq2$. Using a direct method of moving planes, we prove non-existence of
positive solution in the subcritical case.


title:
Meta-analysis of two studies in the presence of heterogeneity with
  applications in rare diseases

abstract:
  Random-effects meta-analyses are used to combine evidence of treatment
effects from multiple studies. Since treatment effects may vary across trials
due to differences in study characteristics, heterogeneity in treatment effects
between studies must be accounted for to achieve valid inference. The standard
model for random-effects meta-analysis assumes approximately normal effect
estimates and a normal random-effects model. However, standard methods based on
this model ignore the uncertainty in estimating the between-trial
heterogeneity. In the special setting of only two studies and in the presence
of heterogeneity we investigate here alternatives such as the
Hartung-Knapp-Sidik-Jonkman method (HKSJ), the modified Knapp-Hartung method
(mKH, a variation of the HKSJ method) and Bayesian random-effects meta-analyses
with priors covering plausible heterogeneity values. The properties of these
methods are assessed by applying them to five examples from various rare
diseases and by a simulation study. Whereas the standard method based on normal
quantiles has poor coverage, the HKSJ and mKH generally lead to very long, and
therefore inconclusive, confidence intervals. The Bayesian intervals on the
whole show satisfying properties and offer a reasonable compromise between
these two extremes.


title:
The non-convex Burer-Monteiro approach works on smooth semidefinite
  programs

abstract:
  Semidefinite programs (SDPs) can be solved in polynomial time by interior
point methods, but scalability can be an issue. To address this shortcoming,
over a decade ago, Burer and Monteiro proposed to solve SDPs with few equality
constraints via rank-restricted, non-convex surrogates. Remarkably, for some
applications, local optimization methods seem to converge to global optima of
these non-convex surrogates reliably. Although some theory supports this
empirical success, a complete explanation of it remains an open question. In
this paper, we consider a class of SDPs which includes applications such as
max-cut, community detection in the stochastic block model, robust PCA, phase
retrieval and synchronization of rotations. We show that the low-rank
Burer--Monteiro formulation of SDPs in that class almost never has any spurious
local optima.


title:
Looking for energy in demographic data; how to detect self-organization
  in human population distribution

abstract:
  In the present work we study the relationship between population allocation
and the combined effects of urban size and energy consumption, for two given
areas and through a major part of the twentieth century. Along these lines a
general application model is laid down which relates city-growth rates to
initial inhabitants and to exosomatic energy increment, the deviations from it
showing order in space and time; as shown in a series of maps which hint at
unaccounted socioeconomic factors. The study of the maps by means of spectral
analysis allows finding patterns which reinforce over time, in such a manner
that spatial frequencies can be determined whose weight increases up so
granting surface evolution estimation.


title: Physical aging in article page views

abstract:
  Statistics of article page views is useful for measuring the impact of
individual articles. Analyzing the temporal evolution of article page views, we
find that article page views usually decay over time after reaching a peak,
especially exhibiting relaxation with nonexponentiality. This finding suggests
that relaxation in article page views resembles physical aging as frequently
found in complex systems.


title: Scale-free networks with exponent one

abstract:
  A majority of studied models for scale-free networks have degree
distributions with exponents greater than $2$. Real networks, however, can
demonstrate essentially more heavy-tailed degree distributions. We explore two
models of scale-free equilibrium networks that have the degree distribution
exponent $\gamma = 1$, $P(q) \sim q^{-\gamma}$. Such degree distributions can
be identified in empirical data only if the mean degree of a network is
sufficiently high. Our models exploit a rewiring mechanism. They are local in
the sense that no knowledge of the network structure, apart from the immediate
neighbourhood of the vertices, is required. These models generate uncorrelated
networks in the infinite size limit, where they are solved explicitly. We
investigate finite size effects by the use of simulations. We find that both
models exhibit disassortative degree-degree correlations for finite network
sizes. In addition, we observe a markedly degree-dependent clustering in the
finite networks. We indicate a real-world network with a similar degree
distribution.


title:
QSWalk: a Mathematica package for quantum stochastic walks on arbitrary
  graphs

abstract:
  We present a Mathematica package, QSWalk, to simulate the time evaluation of
Quantum Stochastic Walks (QSWs) on arbitrary directed and weighted graphs. QSWs
are a generalization of continuous time quantum walks that incorporate both
coherent and incoherent dynamics and as such, include both quantum walks and
classical random walks as special cases. The incoherent component allows for
quantum walks along directed graph edges. The dynamics of QSWs are expressed
using the Lindblad formalism, originally developed for open quantum systems,
which frames the problem in the language of density matrices. For a QSW on a
graph of $N$ vertices, we have a sparse superoperator in an $N^2$-dimensional
space, which can be solved efficiently using the built-in MatrixExp function in
Mathematica. We illustrate the use of the QSWalk package through several
example case studies.


title:
Sharp geometric requirements in the Wachspress interpolation error
  estimate

abstract:
  Geometric conditions on general polygons are given in [9] in order to
guarantee the error estimate for interpolants built from generalized
barycentric coordinates, and the question about identifying sharp geometric
restrictions in this setting is proposed. In this work, we address the question
when the construction is made by using Wachspress coordinates. We basically
show that the imposed conditions: bounded aspect ratio property (barp), maximum
angle condition (MAC) and minimum edge length property (melp) are actually
equivalent to [MAC,melp], and if any of these conditions is not satisfied, then
there is no guarantee that the error estimate is valid. In this sense, MAC and
melp can be regarded as sharp geometric requirements in the Wachspress
interpolation error estimate.


title: Spectroscopic Identification of Type 2 Quasars at Z < 1 in SDSS-III/BOSS

abstract:
  The physics and demographics of type 2 quasars remain poorly understood, and
new samples of such objects selected in a variety of ways can give insight into
their physical properties, evolution, and relationship to their host galaxies.
We present a sample of 2758 type 2 quasars at z $\leq$ 1 from the SDSS-III/BOSS
spectroscopic database, selected on the basis of their emission-line
properties. We probe the luminous end of the population by requiring the
rest-frame equivalent width of [OIII] to be > 100 {\AA}. We distinguish our
objects from star-forming galaxies and type 1 quasars using line widths,
standard emission line ratio diagnostic diagrams at z < 0.52 and detection of
[Ne V]{\lambda}3426{\AA} at z > 0.52. The majority of our objects have [OIII]
luminosities in the range 10^8.5-10^10 L$_{\odot}$ and redshifts between 0.4
and 0.65. Our sample includes over 400 type 2 quasars with incorrectly measured
redshifts in the BOSS database; such objects often show kinematic substructure
or outflows in the [OIII] line. The majority of the sample has counterparts in
the WISE survey, with median infrared luminosity {\nu}L{\nu}[12{\mu}m] = 4.2 x
10^44 erg/sec. Only 34 per cent of the newly identified type 2 quasars would be
selected by infrared color cuts designed to identify obscured active nuclei,
highlighting the difficulty of identifying complete samples of type 2 quasars.
We make public the multi-Gaussian decompositions of all [OIII] profiles for the
new sample and for 568 type 2 quasars from SDSS I/II, together with
non-parametric measures of line profile shapes and identify over 600 candidate
double-peaked [OIII] profiles.


title:
Atom-light interactions in quasi-1D nanostructures: a Green's function
  perspective

abstract:
  Based on a formalism that describes atom-light interactions in terms of the
classical electromagnetic Green's function, we study the optical response of
atoms and other quantum emitters coupled to one-dimensional photonic
structures, such as cavities, waveguides, and photonic crystals. We demonstrate
a clear mapping between the transmission spectra and the local Green's function
that allows to identify signatures of dispersive and dissipative interactions
between atoms. We also demonstrate the applicability of our analysis to
problems involving three-level atoms, such as electromagnetically induced
transparency. Finally we examine recent experiments, and anticipate future
observations of atom-atom interactions in photonic bandgaps.


title: Distance geometry approach for special graph coloring problems

abstract:
  One of the most important combinatorial optimization problems is graph
coloring. There are several variations of this problem involving additional
constraints either on vertices or edges. They constitute models for real
applications, such as channel assignment in mobile wireless networks. In this
work, we consider some coloring problems involving distance constraints as
weighted edges, modeling them as distance geometry problems. Thus, the vertices
of the graph are considered as embedded on the real line and the coloring is
treated as an assignment of positive integers to the vertices, while the
distances correspond to line segments, where the goal is to find a feasible
intersection of them. We formulate different such coloring problems and show
feasibility conditions for some problems. We also propose implicit enumeration
methods for some of the optimization problems based on branch-and-prune methods
proposed for distance geometry problems in the literature. An empirical
analysis was undertaken, considering equality and inequality constraints,
uniform and arbitrary set of distances, and the performance of each variant of
the method considering the handling and propagation of the set of distances
involved.


title:
The re-flight of the Colorado high-resolution Echelle stellar
  spectrograph (CHESS): improvements, calibrations, and post-flight results

abstract:
  In this proceeding, we describe the scientific motivation and technical
development of the Colorado High-resolution Echelle Stellar Spectrograph
(CHESS), focusing on the hardware advancements and testing supporting the
second flight of the payload (CHESS-2). CHESS is a far ultraviolet (FUV)
rocket-borne instrument designed to study the atomic-to-molecular transitions
within translucent cloud regions in the interstellar medium (ISM). CHESS is an
objective f/12.4 echelle spectrograph with resolving power $>$ 100,000 over the
band pass 1000 $-$ 1600 {\AA}. The spectrograph was designed to employ an R2
echelle grating with "low" line density. We compare the FUV performance of
experimental echelle etching processes (lithographically by LightSmyth, Inc.
and etching via electron-beam technology by JPL Microdevices Laboratory) with
traditional, mechanically-ruled gratings (Bach Research, Inc. and Richardson
Gratings). The cross-dispersing grating, developed and ruled by Horiba
Jobin-Yvon, is a holographically-ruled, "low" line density, powered optic with
a toroidal surface curvature. Both gratings were coated with aluminum and
lithium fluoride (Al+LiF) at Goddard Space Flight Center (GSFC). Results from
final efficiency and reflectivity measurements for the optical components of
CHESS-2 are presented. CHESS-2 utilizes a 40mm-diameter cross-strip anode
readout microchannel plate (MCP) detector fabricated by Sensor Sciences, Inc.,
to achieve high spatial resolution with high count rate capabilities (global
rates $>$ 1 MHz). We present pre-flight laboratory spectra and calibration
results. CHESS-2 launched on 21 February 2016 aboard NASA/CU sounding rocket
mission 36.297 UG. We observed the intervening ISM material along the sightline
to $\epsilon$ Per and present initial characterization of the column densities,
temperature, and kinematics of atomic and molecular species in the observation.


title: Detecting continuous gravitational waves with superfluid $^4$He

abstract:
  Direct detection of gravitational waves is opening a new window onto our
universe. Here, we study the sensitivity to continuous-wave strain fields of a
kg-scale optomechanical system formed by the acoustic motion of superfluid
helium-4 parametrically coupled to a superconducting microwave cavity. This
narrowband detection scheme can operate at very high $Q$-factors, while the
resonant frequency is tunable through pressurization of the helium in the
0.1-1.5 kHz range. The detector can therefore be tuned to a variety of
astrophysical sources and can remain sensitive to a particular source over a
long period of time. For reasonable experimental parameters, we find that
strain fields on the order of $h\sim 10^{-23} /\sqrt{\rm Hz}$ are detectable.
We show that the proposed system can significantly improve the limits on
gravitational wave strain from nearby pulsars within a few months of
integration time.

categories: gr-qc astro-ph.IM cond-mat.other quant-ph


title:
GMC Evolution in a Barred Spiral Galaxy with Star Formation and Thermal
  Feedback

abstract:
  We explore the impact of star formation and thermal stellar feedback on the
giant molecular cloud (GMC) population forming in a M83-type barred spiral
galaxy. We compare three high-resolution simulations (1.5 pc cell size) with
different star formation/feedback models: one with no star formation, one with
star formation but no feedback, and one with star formation and thermal energy
injection. We analyze the resulting population of clouds, finding that we can
identify the same population of massive, virialized clouds and transient,
low-surface density clouds found in our previous work (that did not include
star formation or feedback). Star formation and feedback can affect the mix of
clouds we identify. In particular, star formation alone simply converts dense
cloud gas into stars with only a small change to the cloud populations,
principally resulting in a slight decrease in the transient population.
Feedback, however, has a stronger impact: while it is not generally sufficient
to entirely destroy the clouds, it does eject gas out of them, increasing the
gas density in the inter-cloud region. This decreases the number of massive
clouds, but substantially increases the transient cloud population. We also
find that feedback tends to drive a net radial inflow of massive clouds,
leading to an increase in the star formation rate in the bar region. We examine
a number of possible reasons for this and conclude that it is possible that the
drag force from the enhanced intercloud density could be responsible.


title:
Di-nucleon structures in homogeneous nuclear matter based on two- and
  three-nucleon interactions

abstract:
  We investigate homogeneous nuclear matter within the Brueckner-Hartree-Fock
(BHF) approach in the limits of isospin-symmetric nuclear matter (SNM) as well
as pure neutron matter at zero temperature. The study is based on realistic
representations of the internucleon interaction as given by Argonne v18, Paris,
Nijmegen I and II potentials, in addition to chiral N$^{3}$LO interactions,
including three-nucleon forces up to N$^{2}$LO. Particular attention is paid to
the presence of di-nucleon bound states structures in $^1\textrm{S}_0$ and
$^3\textrm{SD}_1$ channels, whose explicit account becomes crucial for the
stability of self-consistent solutions at low densities. A characterization of
these solutions and associated bound states is discussed. We confirm that
coexisting BHF single-particle solutions in SNM, at Fermi momenta in the range
$0.13-0.3$~fm$^{-1}$, is a robust feature under the choice of realistic
internucleon potentials.


title: SZ/X-ray scaling relations using X-ray data and Planck Nominal maps

abstract:
  We determine the relation between the Comptonization parameter predicted
using X-ray data $Y_{C,Xray}$ and the X-ray luminosity $L_X$, both magnitudes
derived from ROSAT data, with the Comptonization parameter $Y_{C,SZ}$ measured
on {\it Planck} 2013 foreground cleaned Nominal maps. The 560 clusters of our
sample includes clusters with masses $M\ge 10^{13}M_\odot$, one order of
magnitude smaller than those used by the Planck Collaboration in a similar
analysis. It also contains eight times more clusters in the redshift interval
$z\le 0.3$. The prediction of the $\beta=2/3$ model convolved with the Planck
antenna beam agrees with the anisotropies measured in foreground cleaned Planck
Nominal maps within the X-ray emitting region, confirming the results of an
earlier analysis (Atrio-Barandela et al. 2008). The universal pressure profile
overestimates the signal by a 15-21\% depending on the angular aperture. We
show that the discrepancy is not due to the presence of {\it cool-core} systems
but it is an indication of a brake in the $L_X-M$ relation towards low mass
systems. We show that relation of the Comptonization parameter averaged over
the region that emits 99\% of the X-ray flux and and the X-ray luminosity is
consistent with the predictions of the self-similar model. We confirm previous
findings that the scaling relations studied here do not evolve with redshift
within the range probed by our catalog.


title:
Understanding the Factors that Impact the Popularity of GitHub
  Repositories

abstract:
  Software popularity is a valuable information to modern open source
developers, who constantly want to know if their systems are attracting new
users, if new releases are gaining acceptance, or if they are meeting user's
expectations. In this paper, we describe a study on the popularity of software
systems hosted at GitHub, which is the world's largest collection of open
source software. GitHub provides an explicit way for users to manifest their
satisfaction with a hosted repository: the stargazers button. In our study, we
reveal the main factors that impact the number of stars of GitHub projects,
including programming language and application domain. We also study the impact
of new features on project popularity. Finally, we identify four main patterns
of popularity growth, which are derived after clustering the time series
representing the number of stars of 2,279 popular GitHub repositories. We hope
our results provide valuable insights to developers and maintainers, which can
help them on building and evolving systems in a competitive software market.


title:
Combining multiscale features for classification of hyperspectral
  images: a sequence based kernel approach

abstract:
  Nowadays, hyperspectral image classification widely copes with spatial
information to improve accuracy. One of the most popular way to integrate such
information is to extract hierarchical features from a multiscale segmentation.
In the classification context, the extracted features are commonly concatenated
into a long vector (also called stacked vector), on which is applied a
conventional vector-based machine learning technique (e.g. SVM with Gaussian
kernel). In this paper, we rather propose to use a sequence structured kernel:
the spectrum kernel. We show that the conventional stacked vector-based kernel
is actually a special case of this kernel. Experiments conducted on various
publicly available hyperspectral datasets illustrate the improvement of the
proposed kernel w.r.t. conventional ones using the same hierarchical spatial
features.


title: Power Series with Coefficients from a Finite Set

abstract:
  We prove in this paper that a multivariate D-finite power series with
coefficients from a finite set is rational. This generalizes a rationality
theorem of van der Poorten and Shparlinski in 1996.


title:
Automatic finite element implementation of hyperelastic material with a
  double numerical differentiation algorithm

abstract:
  In order to accelerate implementation of hyperelastic materials for finite
element analysis, we developed an automatic numerical algorithm that only
requires the strain energy function. This saves the effort on analytical
derivation and coding of stress and tangent modulus, which is time-consuming
and prone to human errors. Using the one-sided Newton difference quotients, the
proposed algorithm first perturbs deformation gradients and calculate the
difference on strain energy to approximate stress. Then, we perturb again to
get difference in stress to approximate tangent modulus. Accuracy of the
approximations were evaluated across the perturbation parameter space, where we
find the optimal amount of perturbation being $10^{-6}$ to obtain stress and
$10^{-4}$ to obtain tangent modulus. Single element verification in ABAQUS with
Neo-Hookean material resulted in a small stress error of only $7\times10^{-5}$
on average across uniaxial compression and tension, biaxial tension and simple
shear situations. A full 3D model with Holzapfel anisotropic material for
artery inflation generated a small relative error of $4\times10^{-6}$ for
inflated radius at $25 kPa$ pressure. Results of the verification tests suggest
that the proposed numerical method has good accuracy and convergence
performance, therefore a good material implementation algorithm in small scale
models and a useful debugging tool for large scale models.


title: Logarithmic Time One-Against-Some

abstract:
  We create a new online reduction of multiclass classification to binary
classification for which training and prediction time scale logarithmically
with the number of classes. Compared to previous approaches, we obtain
substantially better statistical performance for two reasons: First, we prove a
tighter and more complete boosting theorem, and second we translate the results
more directly into an algorithm. We show that several simple techniques give
rise to an algorithm that can compete with one-against-all in both space and
predictive power while offering exponential improvements in speed when the
number of classes is large.


title:
Detection of an oxygen emission line from a high redshift galaxy in the
  reionization epoch

abstract:
  The physical properties and elemental abundances of the interstellar medium
in galaxies during cosmic reionization are important for understanding the role
of galaxies in this process. We report the Atacama Large
Millimeter/submillimeter Array detection of an oxygen emission line at a
wavelength of 88 micrometers from a galaxy at an epoch about 700 million years
after the Big Bang. The oxygen abundance of this galaxy is estimated at about
one-tenth that of the Sun. The non-detection of far-infrared continuum emission
indicates a deficiency of interstellar dust in the galaxy. A carbon emission
line at a wavelength of 158 micrometers is also not detected, implying an
unusually small amount of neutral gas. These properties might allow ionizing
photons to escape into the intergalactic medium.


title: A New Three-Dimensional Track Fit with Multiple Scattering

abstract:
  Modern semiconductor detectors allow for charged particle tracking with ever
increasing position resolution. Due to the reduction of the spatial hit
uncertainties, multiple Coulomb scattering in the detector layers becomes the
dominant source for tracking uncertainties. In this case long distance effects
can be ignored for the momentum measurement, and the track fit can consequently
be formulated as a sum of independent fits to hit triplets. In this paper we
present an analytical solution for a three-dimensional triplet(s) fit in a
homogeneous magnetic field based on a multiple scattering model. Track fitting
of hit triplets is performed using a linearization ansatz. The momentum
resolution is discussed for a typical spectrometer setup. Furthermore the track
fit is compared with other track fits for two different pixel detector
geometries, namely the Mu3e experiment at PSI and a typical high-energy
collider experiment. For a large momentum range the triplets fit provides a
significantly better performance than a single helix fit. The triplets fit is
fast and can easily be parallelized, which makes it ideal for the
implementation on parallel computing architectures.

categories: physics.ins-det hep-ex physics.comp-ph physics.data-an


title:
A Class of Parallel Doubly Stochastic Algorithms for Large-Scale
  Learning

abstract:
  We consider learning problems over training sets in which both, the number of
training examples and the dimension of the feature vectors, are large. To solve
these problems we propose the random parallel stochastic algorithm (RAPSA). We
call the algorithm random parallel because it utilizes multiple parallel
processors to operate on a randomly chosen subset of blocks of the feature
vector. We call the algorithm stochastic because processors choose training
subsets uniformly at random. Algorithms that are parallel in either of these
dimensions exist, but RAPSA is the first attempt at a methodology that is
parallel in both the selection of blocks and the selection of elements of the
training set. In RAPSA, processors utilize the randomly chosen functions to
compute the stochastic gradient component associated with a randomly chosen
block. The technical contribution of this paper is to show that this minimally
coordinated algorithm converges to the optimal classifier when the training
objective is convex. Moreover, we present an accelerated version of RAPSA
(ARAPSA) that incorporates the objective function curvature information by
premultiplying the descent direction by a Hessian approximation matrix. We
further extend the results for asynchronous settings and show that if the
processors perform their updates without any coordination the algorithms are
still convergent to the optimal argument. RAPSA and its extensions are then
numerically evaluated on a linear estimation problem and a binary image
classification task using the MNIST handwritten digit dataset.


title:
A Hierarchical Pose-Based Approach to Complex Action Understanding Using
  Dictionaries of Actionlets and Motion Poselets

abstract:
  In this paper, we introduce a new hierarchical model for human action
recognition using body joint locations. Our model can categorize complex
actions in videos, and perform spatio-temporal annotations of the atomic
actions that compose the complex action being performed.That is, for each
atomic action, the model generates temporal action annotations by estimating
its starting and ending times, as well as, spatial annotations by inferring the
human body parts that are involved in executing the action. our model includes
three key novel properties: (i) it can be trained with no spatial supervision,
as it can automatically discover active body parts from temporal action
annotations only; (ii) it jointly learns flexible representations for motion
poselets and actionlets that encode the visual variability of body parts and
atomic actions; (iii) a mechanism to discard idle or non-informative body parts
which increases its robustness to common pose estimation errors. We evaluate
the performance of our method using multiple action recognition benchmarks. Our
model consistently outperforms baselines and state-of-the-art action
recognition methods.


title:
Monotone and Convex Stochastic Orders for Processes with Independent
  Increments

abstract:
  We study monotone and convex stochastic orders for processes with independent
increments. Our contributions are twofold: First, we relate stochastic orders
of the Poisson component to orders of their (generalized) L\'evy measures. The
relation is proven using an interpolation formula for infinitely divisible
laws. Second, we derive explicit conditions on the characteristics of the
processes. In this case, we prove the conditions via constructions of
couplings.


title:
Universal behavior of the Shannon mutual information in non-integrable
  self-dual quantum chains

abstract:
  An existing conjecture states that the Shannon mutual information contained
in the ground state wavefunction of conformally invariant quantum chains, on
periodic lattices, has a leading finite-size scaling behavior that, similarly
as the von Neumann entanglement entropy, depends on the value of the central
charge of the underlying conformal field theory describing the physical
properties. This conjecture applies whenever the ground state wavefunction is
expressed in some special basis (conformal basis). Its formulation comes mainly
from numerical evidences on exactly integrable quantum chains. In this paper
the above conjecture was tested for several general non-integrable quantum
chains. We introduce new families of self-dual $Z(Q)$ symmetric quantum chains
($Q=2,3,\ldots$). These quantum chains contain nearest neighbour as well
next-nearest neighbour interactions (coupling constant $p$). In the cases $Q=2$
and $Q=3$ they are extensions of the standard quantum Ising and 3-state Potts
chains, respectively. For $Q=4$ and $Q\geq 5$ they are extensions of the
Ashkin-Teller and $Z(Q)$ parafermionic quantum chains. Our studies indicate
that these models are interesting on their own. They are critical, conformally
invariant, and share the same universality class in a continuous critical line.
Moreover, our numerical analysis for $Q=2-8$ indicate that the Shannon mutual
information exhibits the conjectured behaviour irrespective if the conformally
invariant quantum chain is exactly integrable or not. For completeness we also
calculated, for these new families of quantum chains, the two existing
generalizations of the Shannon mutual information, which are based on the
R\'enyi entropy and on the R\'enyi divergence.


title:
Joint Data Compression and MAC Protocol Design for Smartgrids with
  Renewable Energy

abstract:
  In this paper, we consider the joint design of data compression and
802.15.4-based medium access control (MAC) protocol for smartgrids with
renewable energy. We study the setting where a number of nodes, each of which
comprises electricity load and/or renewable sources, report periodically their
injected powers to a data concentrator. Our design exploits the correlation of
the reported data in both time and space to efficiently design the data
compression using the compressed sensing (CS) technique and theMAC protocol so
that the reported data can be recovered reliably within minimum reporting time.
Specifically, we perform the following design tasks: i) we employ the
two-dimensional (2D) CS technique to compress the reported data in the
distributed manner; ii) we propose to adapt the 802.15.4 MAC protocol frame
structure to enable efficient data transmission and reliable data
reconstruction; and iii) we develop an analytical model based on which we can
obtain efficient MAC parameter configuration to minimize the reporting delay.
Finally, numerical results are presented to demonstrate the effectiveness of
our proposed framework compared to existing solutions.

categories: cs.NI cs.IT math.IT math.OC math.ST stat.ML stat.TH


title:
Constraining modified theories of gravity with gravitational wave
  stochastic background

abstract:
  The direct discovery of gravitational waves has finally opened a new
observational window on our Universe, suggesting that the population of
coalescing binary black holes is larger than previously expected. These sources
produce an unresolved background of gravitational waves, potentially
observables by ground-based interferometers. In this paper we investigate how
modified theories of gravity, modeled using the ppE formalism, affect the
expected signal, and analyze the detectability of the resulting stochastic
background by current and future ground-based interferometers. We find the
constraints that AdLIGO would be able to set on modified theories, showing that
they may significantly improve the current bounds obtained from astrophysical
observations of binary pulsars.


title:
Adaptive Quorum-Based Channel-Hopping Distributed Coordination Scheme
  for Cognitive Radio Networks

abstract:
  One of the most important challenges in deploying cognitive radio networks
(CRNs) is to find a common control channel (CCC) to all secondary users (SUs)
that enables efficient CR communications. This challenge is attributed to the
dynamic time-varying change of network topology, location and spectrum
availability conditions. Rendezvous, which is the process of establishing
control communications, is an essential requirement to enable efficient
communication between any two pair of CR nodes. The most popular CR rendezvous
protocols are based on quorum systems (QSs). Quorum systems are systematic
approaches, which have several attractive properties that can be utilized to
establish communication without the need of a CCC and so overcome the
rendezvous (RDV) problem.
  In this thesis, we propose new channel-hopping-based distributed rendezvous
algorithm based on grid-based-quorum techniques. The proposed algorithm
increases the probability of RDV within a single cycle by allowing CR nodes to
meet more often according to intersection property of quorum systems. Our
proposed algorithm is called Adaptive_Quorum-Based Channel-Hopping Distributed
Coordination Scheme for Cognitive Radio Networks. The main idea of our
algorithm is to dynamically adjusting the selected QS by CR users according to
the varying traffic loads in the CRN. The proposed algorithm decreases the
average time to rendezvous (TTR) and increase the probability of RDV. We
evaluate the performance of our algorithm through Matlab simulations. The
performance of proposed algorithm is compared with two different design scheme.
The results show that our algorithm can reduce TTR, increase the RDV, and
decrease the energy consumption per successful RDV.


title: Strong analog classical simulation of coherent quantum dynamics

abstract:
  A strong analog classical simulation of general quantum evolution is
proposed, which serves as a novel scheme in quantum computation and simulation.
The scheme employs the approach of geometric quantum mechanics and quantum
informational technique of quantum tomography, which applies broadly to cases
of mixed states, nonunitary evolution, and infinite dimensional systems. The
simulation provides an intriguing classical picture to probe quantum phenomena,
namely, a coherent quantum dynamics can be viewed as a globally constrained
classical Hamiltonian dynamics of a collection of coupled particles or strings.
Efficiency analysis reveals a fundamental difference between the locality in
real space and locality in Hilbert space, the latter enables efficient strong
analog classical simulations. Examples are also studied to highlight the
differences and gaps among various simulation methods.


title: Pseudo-Kan Extensions and Descent Theory

abstract:
  There are two main constructions in classical descent theory: the category of
algebras and the descent category, which are known to be examples of weighted
bilimits. We give a formal approach to descent theory, employing formal
consequences of commuting properties of bilimits to prove classical and new
theorems in the context of Janelidze-Tholen "Facets of Descent II", such as
B\'{e}nabou-Roubaud Theorems, a Galois Theorem, embedding results and formal
ways of getting effective descent morphisms. In order to do this, we develop
the formal part of the theory on commuting bilimits via pseudomonad theory,
studying idempotent pseudomonads and proving a $2$-dimensional version of the
adjoint triangle theorem. Also, we work out the concept of pointwise pseudo-Kan
extension, used as a framework to talk about bilimits, commutativity and the
descent object. As a subproduct, this formal approach can be an alternative
perspective/guiding template for the development of higher descent theory.


title:
The Bootstrapped Robustness Assessment for Qualitative Comparative
  Analysis

abstract:
  Qualitative Comparative Analysis (QCA) has been increasingly used in recent
years due to its purported construction of a middle path between case-oriented
and variable-oriented methods. Despite its popularity, a key element of the
method has been criticized for possibly not distinguishing random from real
patterns in data, rendering its usefulness questionable. Critics of the method
suggest a straightforward technique to test whether QCA will return a
configuration when given random data. We adapt this technique to determine the
probability that a given QCA application would return a random result. This
assessment can be used as a hypothesis test for QCA, with an interpretation
similar to a p-value. Using repeated applications of QCA to randomly-generated
data, we first show that generally, the tendency for QCA to return spurious
results is attenuated by using reasonable consistency score and configurational
N thresholds; however, this varies considerably according to the basic
structure of the data. Second, we suggest an application-specific assessment of
QCA results, illustrated using the case of Tea Party rallies in Florida. This
method, which we coin the Bootstrapped Robustness Assessment for QCA (baQCA),
can provide researchers with recommendations for consistency score and
configurational N thresholds.


title:
Swift follow-up of gravitational wave triggers: results from the first
  aLIGO run and optimisation for the future

abstract:
  During its first observing run, in late 2015, the advanced LIGO facility
announced 3 gravitational wave (GW) triggers to electromagnetic follow-up
partners. Two of these have since been confirmed as being of astrophysical
origin: both are binary black hole mergers at ~500 Mpc; the other trigger was
later found not to be astrophysical. In this paper we report on the Swift
follow up observations of the second and third triggers, including details of
21 X-ray sources detected; none of which can be associated with the GW event.
We also consider the challenges that the next GW observing run will bring as
the sensitivity and hence typical distance of GW events will increase. We
discuss how to effectively use galaxy catalogues to prioritise areas for follow
up, especially in the presence of distance estimates from the GW data. We also
consider two galaxy catalogues and suggest that the high completeness at larger
distances of the 2MASS Photometric Redshift Catalogue (2MPZ) makes it very well
suited to optimise Swift follow-up observations.


title:
3DFS: Deformable Dense Depth Fusion and Segmentation for Object
  Reconstruction from a Handheld Camera

abstract:
  We propose an approach for 3D reconstruction and segmentation of a single
object placed on a flat surface from an input video. Our approach is to perform
dense depth map estimation for multiple views using a proposed objective
function that preserves detail. The resulting depth maps are then fused using a
proposed implicit surface function that is robust to estimation error,
producing a smooth surface reconstruction of the entire scene. Finally, the
object is segmented from the remaining scene using a proposed 2D-3D
segmentation that incorporates image and depth cues with priors and
regularization over the 3D volume and 2D segmentations. We evaluate 3D
reconstructions qualitatively on our Object-Videos dataset, comparing to
fusion, multiview stereo, and segmentation baselines. We also quantitatively
evaluate the dense depth estimation using the RGBD Scenes V2 dataset [Henry et
al. 2013] and the segmentation using keyframe annotations of the Object-Videos
dataset.


title:
The mass discrepancy acceleration relation in early-type galaxies:
  extended mass profiles and the phantom menace to MOND

abstract:
  The dark matter (DM) haloes around spiral galaxies appear to conspire with
their baryonic content: empirically, significant amounts of DM are inferred
only below a universal characteristic acceleration scale. Moreover, the
discrepancy between the baryonic and dynamical mass, which is usually
interpreted as the presence of DM, follows a very tight mass discrepancy
acceleration (MDA) relation. Its universality, and its tightness in spiral
galaxies, poses a challenge for the DM interpretation and was used to argue in
favour of MOdified Newtonian Dynamics (MOND). Here, we test whether or not this
applies to early-type galaxies. We use the dynamical models of fast-rotator
early-type galaxies by Cappellari et al. based on ATLAS$^{3D}$ and SLUGGS data,
which was the first homogenous study of this kind, reaching ~4 $R_e$, where DM
begins to dominate the total mass budget. We find the early-type galaxies to
follow an MDA relation similar to spiral galaxies, but systematically offset.
Also, while the slopes of the mass density profiles inferred from galaxy
dynamics show consistency with those expected from their stellar content
assuming MOND, some profiles of individual galaxies show discrepancies.


title: Temporal and Semantic Effects on Multisensory Integration

abstract:
  How do we integrate modality-specific perceptual information arising from the
same physical event into a coherent percept? One possibility is that observers
rely on information across perceptual modalities that shares temporal structure
and/or semantic associations. To explore the contributions of these two factors
in multisensory integration, we manipulated the temporal and semantic
relationships between auditory and visual information produced by real-world
events, such as paper tearing or cards being shuffled. We identified distinct
neural substrates for integration based on temporal structure as compared to
integration based on event semantics. Semantically incongruent events recruited
left frontal regions, while temporally asynchronous events recruited right
frontal cortices. At the same time, both forms of incongruence recruited
subregions in the temporal, occipital, and lingual cortices. Finally, events
that were both temporally and semantically congruent modulated activity in the
parahippocampus and anterior temporal lobe. Taken together, these results
indicate that low-level perceptual properties such as temporal synchrony and
high-level knowledge such as semantics play a role in our coherent perceptual
experience of physical events.


title: Feedback Integrators

abstract:
  A new method is proposed to numerically integrate a dynamical system on a
manifold such that the trajectory stably remains on the manifold and preserves
first integrals of the system. The idea is that given an initial point in the
manifold we extend the dynamics from the manifold to its ambient Euclidean
space and then modify the dynamics outside the intersection of the manifold and
the level sets of the first integrals containing the initial point such that
the intersection becomes a unique local attractor of the resultant dynamics.
While the modified dynamics theoretically produces the same trajectory as the
original dynamics, it yields a numerical trajectory that stably remains on the
manifold and preserves the first integrals. The big merit of our method is that
the modified dynamics can be integrated with any ordinary numerical integrator
such as Euler or Runge-Kutta. We illustrate this method by applying it to three
famous problems: the free rigid body, the Kepler problem and a perturbed Kepler
problem with rotational symmetry. We also carry out simulation studies to
demonstrate the excellence of our method and make comparisons with the standard
projection method, a splitting method and St\"ormer-Verlet schemes.


title: Animated 3D Human Models for Use in Person Recognition Experiments

abstract:
  The development of increasingly realistic experimental stimuli and task
environments is important for understanding behavior outside the laboratory. We
report a process for generating 3D human model stimuli that combines commonly
used graphics software and enables the flexible generation of animated human
models while providing parametric control over individualized identity
features. Our approach creates novel head models using FaceGen Modeller,
attaches them to commercially-purchased 3D avatar bodies in 3D Studio Max, and
generates Cal3D human models that are compatible with many virtual 3D
environments. Stimuli produced by this method can be embedded as animated 3D
avatars in interactive simulations or presented as 2D images embedded in scenes
for use in traditional laboratory experiments. The inherent flexibility in this
method makes the stimuli applicable to a broad range of basic and applied
research questions in the domain of person perception. We describe the steps of
the stimulus generation process, provide an example of their use in a
recognition memory paradigm, and highlight the adaptability of the method for
related avenues of research.


title:
Automatic Pronunciation Generation by Utilizing a Semi-supervised Deep
  Neural Networks

abstract:
  Phonemic or phonetic sub-word units are the most commonly used atomic
elements to represent speech signals in modern ASRs. However they are not the
optimal choice due to several reasons such as: large amount of effort required
to handcraft a pronunciation dictionary, pronunciation variations, human
mistakes and under-resourced dialects and languages. Here, we propose a
data-driven pronunciation estimation and acoustic modeling method which only
takes the orthographic transcription to jointly estimate a set of sub-word
units and a reliable dictionary. Experimental results show that the proposed
method which is based on semi-supervised training of a deep neural network
largely outperforms phoneme based continuous speech recognition on the TIMIT
dataset.


title:
Kremer-Grest models for universal properties of specific common polymer
  species

abstract:
  The Kremer-Grest (KG) bead-spring model is a near standard in Molecular
Dynamic simulations of generic polymer properties. It owes its popularity to
its computational efficiency, rather than its ability to represent specific
polymer species and conditions. Here we investigate how to adapt the model to
match the universal properties of a wide range of chemical polymers species.
For this purpose we vary a single parameter originally introduced by Faller and
M\"uller-Plathe, the chain stiffness. Examples include polystyrene,
polyethylene, polypropylene, cis-polyisoprene, polydimethylsiloxane,
polyethyleneoxide and styrene-butadiene rubber. We do this by matching the
number of Kuhn segments per chain and the number of Kuhn segments per cubic
Kuhn volume for the polymer species and for the Kremer-Grest model. We also
derive mapping relations for converting KG model units back to physical units,
in particular we obtain the entanglement time for the KG model as function of
stiffness allowing for a time mapping. To test these relations, we generate
large equilibrated well entangled polymer melts, and measure the entanglement
moduli using a static primitive-path analysis of the entangled melt structure
as well as by simulations of step-strain deformation of the model melts. The
obtained moduli for our model polymer melts are in good agreement with the
experimentally expected moduli.


title: On biadjoint triangles

abstract:
  We prove a biadjoint triangle theorem and its strict version, which are
$2$-dimensional analogues of the adjoint triangle theorem of Dubuc. Similarly
to the $1$-dimensional case, we demonstrate how we can apply our results to get
the pseudomonadicity characterization (due to Le Creurer, Marmolejo and
Vitale).
  Furthermore, we study applications of our main theorems in the context of the
$2$-monadic approach to coherence. As a direct consequence of our strict
biadjoint triangle theorem, we give the construction (due to Lack) of the left
$2$-adjoint to the inclusion of the strict algebras into the pseudoalgebras.
  In the last section, we give two brief applications on lifting biadjunctions
and pseudo-Kan extensions.


title: Polarization shaping for control of nonlinear propagation

abstract:
  We study the nonlinear optical propagation of two different classes of
space-varying polarized light beams -- radially symmetric vector beams and
Poincar\'e beams with lemon and star topologies -- in a rubidium vapour cell.
Unlike Laguerre-Gauss and other types of beams that experience modulational
instabilities, we observe that their propagation is not marked by beam breakup
while still exhibiting traits such as nonlinear confinement and self-focusing.
Our results suggest that by tailoring the spatial structure of the
polarization, the effects of nonlinear propagation can be effectively
controlled. These findings provide a novel approach to transport high-power
light beams in nonlinear media with controllable distortions to their spatial
structure and polarization properties.


title: Wronskians of Fourier and Laplace Transforms

abstract:
  Associated with a given suitable function, or a measure, on $\mathbb{R}$, we
introduce a correlation function, so that the Wronskian of the Fourier
transform of the function is the Fourier transform of the corresponding
correlation function, and the same holds for the Laplace transform. We obtain
two types of results. First, we show that Wronskians of the Fourier transform
of a nonnegative function on $\mathbb{R}$ are positive definite functions and
the Wronskians of the Laplace transform of a nonnegative function on
$\mathbb{R}_+$ are completely monotone functions. Then we establish necessary
and sufficient conditions in order that a real entire function, defined as a
Fourier transform of a positive kernel $K$, belongs to the Laguerre-P\'olya
class, which answers an old question of P\'olya. The characterization is given
in terns of a density property of the correlation kernel related to $K$, via
classical results of Laguerre and Jensen and employing Wiener's $L^1$ Tauberian
theorem. As a consequence we provide a necessary and sufficient condition for
the Riemann hypothesis in terms of a density of the translations of the
correlation function related to the Riemann $\xi$-function.


title:
Spinodal instabilities of baryon-rich quark matter in heavy ion
  collisions

abstract:
  Using the test-particle method to solve the transport equation derived from
the Nambu-Jona-Lasino (NJL) model, we study how phase separation occurs in an
expanding quark matter like that in a heavy ion collision. To test our method,
we first investigate the growth rates of unstable modes of quark matter in a
static cubic box and find them to agree with the analytical results that were
previously obtained using the linear response theory. In this case, we also
find the higher-order scaled density moments to increase with time and saturate
at values significantly larger than one, which corresponds to a uniform density
distribution, after the phase separation. The skewness of the quark number
event-by-event distribution in a small sub-volume of the system is also found
to increase, but this feature disappears if the sub-volume is large. For the
expanding quark matter, two cases are considered with one using a blast-wave
model for the initial conditions and the other using initial conditions from a
mulple-phase transport (AMPT) model. In both cases, we find the expansion of
the quark matter is slowed down by the presence of a first-order phase
transition. Also, density clumps appear in the system and the momentum
distribution of partons becomes anisotropic , which can be characterized by
large scaled density moments and non-vanishing anisotropic elliptic and
quadrupolar flows, respectively. The large density fluctuations further lead to
an enhancement in the dilepton yield. In the case with the AMPT initial
conditions, the presence of a first-order phase transition also results in a
narrower rapidity distribution of partons after their freeze out. These effects
of density fluctuations can be regarded as possible signals for a first-order
phase transition that occurs in the baryon-rich quark matter formed in
relativistic heavy ion collisions.


title: On a nonisothermal ideal gas Navier-Stokes-Fourier equations

abstract:
  In this paper we are concerned with a non-isothermal compressible
Navier-Stokes-Fourier model with density dependent viscosity that vanish on the
vacuum. We prove sequential stability of variational weak solutions in periodic
domain \Omega= T3. The main point is that the pressure is given by P =
R\rho\theta.


title: Global existence of weak solutions for generalized quantum MHD equation

abstract:
  We prove the existence of a weak solution to a generalized quantum MHD
equation in a 2-dimensional periodic box for large initial data. The existence
of a global weak solution is established through a three-level approximation,
energy estimates, and weak convergence for the adiabatic exponent \gamma>1.


title: Intertwined Orders in Heavy-Fermion Superconductor CeCoIn$_5$

abstract:
  The appearance of spin-density-wave (SDW) magnetic order in the
low-temperature and high-field corner of the superconducting phase diagram of
CeCoIn$_5$ is unique among unconventional superconductors. The nature of this
magnetic $Q$ phase is a matter of current debate. Here, we present the thermal
conductivity of CeCoIn$_5$ in a rotating magnetic field, which reveals the
presence of an additional order inside the $Q$ phase that is intimately
intertwined with the superconducting $d$-wave and SDW orders. A discontinuous
change of the thermal conductivity within the $Q$ phase, when the magnetic
field is rotated about antinodes of the superconducting $d$-wave order
parameter, demands that the additional order must change abruptly together with
the recently observed switching of the SDW. A combination of interactions,
where spin-orbit coupling orients the SDW, which then selects the secondary
$p$-wave pair-density-wave component (with an average amplitude of 20\% of the
primary $d$-wave order parameter), accounts for the observed behavior.


title:
Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle
  tail radio galaxy

abstract:
  We have discovered a previously unreported poor cluster of galaxies (RGZ-CL
J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in
the Radio Galaxy Zoo project. We obtained a spectroscopic redshift of
$z=0.0897$ for the E0-type host galaxy, 2MASX J08231289+0333016, leading to
M$_r = -22.6$ and a $1.4\,$GHz radio luminosity density of $L_{\rm 1.4} =
5.5\times10^{24}$ W Hz$^{-1}$. These radio and optical luminosities are typical
for wide-angle tailed radio galaxies near the borderline between Fanaroff-Riley
(FR) classes I and II. The projected largest angular size of $\approx8\,$arcmin
corresponds to $800\,$kpc and the full length of the source along the curved
jets/trails is $1.1\,$Mpc in projection. X-ray data from the XMM-Newton archive
yield an upper limit on the X-ray luminosity of the thermal emission
surrounding RGZ J082312.9+033301,at $1.2-2.6\times10^{43}$ erg s$^{-1}$ for
assumed intra-cluster medium temperatures of $1.0-5.0\,$keV. Our analysis of
the environment surrounding RGZ J082312.9+033301 indicates that RGZ
J082312.9+033301 lies within a poor cluster. The observed radio morphology
suggests that (a) the host galaxy is moving at a significant velocity with
respect to an ambient medium like that of at least a poor cluster, and that (b)
the source may have had two ignition events of the active galactic nucleus with
$10^7\,$yrs in between. This reinforces the idea that an association between
RGZ J082312.9+033301, and the newly discovered poor cluster exists.


title:
SocialHBC: Social Networking and Secure Authentication using
  Interference-Robust Human Body Communication

abstract:
  With the advent of cheap computing through five decades of continued
miniaturization following Moores Law, wearable devices are becoming
increasingly popular. These wearable devices are typically interconnected using
wireless body area network (WBAN). Human body communication (HBC) provides an
alternate energy-efficient communication technique between on-body wearable
devices by using the human body as a conducting medium. This allows order of
magnitude lower communication power, compared to WBAN, due to lower loss and
broadband signaling. Moreover, HBC is significantly more secure than WBAN, as
the information is contained within the human body and cannot be snooped on
unless the person is physically touched. In this paper, we highlight
applications of HBC as (1) Social Networking (e.g. LinkedIn/Facebook friend
request sent during Handshaking in a meeting/party), (2) Secure Authentication
using human-human or human-machine dynamic HBC and (3) ultra-low power, secure
BAN using intra-human HBC. One of the biggest technical bottlenecks of HBC has
been the interference (e.g. FM) picked up by the human body acting like an
antenna. In this work, for the first time, we introduce an integrating dual
data rate (DDR) receiver technique, that allows notch filtering (>20 dB) of the
interference for interference-robust HBC.


title: Improving Power Generation Efficiency using Deep Neural Networks

abstract:
  Recently there has been significant research on power generation,
distribution and transmission efficiency especially in the case of renewable
resources. The main objective is reduction of energy losses and this requires
improvements on data acquisition and analysis. In this paper we address these
concerns by using consumers' electrical smart meter readings to estimate
network loading and this information can then be used for better capacity
planning. We compare Deep Neural Network (DNN) methods with traditional methods
for load forecasting. Our results indicate that DNN methods outperform most
traditional methods. This comes at the cost of additional computational
complexity but this can be addressed with the use of cloud resources. We also
illustrate how these results can be used to better support dynamic pricing.


title: On a class of left metacyclic codes

abstract:
  Let $G_{(m,3,r)}=\langle x,y\mid x^m=1, y^3=1,yx=x^ry\rangle$ be a metacyclic
group of order $3m$, where ${\rm gcd}(m,r)=1$, $1<r<m$ and $r^3\equiv 1$ (mod
$m$). Then left ideals of the group algebra $\mathbb{F}_q[G_{(m,3,r)}]$ are
called left metacyclic codes over $\mathbb{F}_q$ of length $3m$, and
abbreviated as left $G_{(m,3,r)}$-codes. A system theory for left
$G_{(m,3,r)}$-codes is developed for the case of ${\rm gcd}(m,q)=1$ and
$r\equiv q^\epsilon$ for some positive integer $\epsilon$, only using finite
field theory and basic theory of cyclic codes and skew cyclic codes. The fact
that any left $G_{(m,3,r)}$-code is a direct sum of concatenated codes with
inner codes ${\cal A}_i$ and outer codes $C_i$ is proved, where ${\cal A}_i$ is
a minimal cyclic code over $\mathbb{F}_q$ of length $m$ and $C_i$ is a skew
cyclic code of length $3$ over an extension field of $\mathbb{F}_q$. Then an
explicit expression for each outer code in any concatenated code is provided.
Moreover, the dual code of each left $G_{(m,3,r)}$-code is given and
self-orthogonal left $G_{(m,3,r)}$-codes are determined.