title: Stochastic higher spin six vertex model and q-TASEPs

abstract:
  We present two new connections between the inhomogeneous stochastic higher
spin six vertex model in a quadrant and integrable stochastic systems from the
Macdonald processes hierarchy. First, we show how Macdonald $q$-difference
operators with $t=0$ (an algebraic tool crucial for studying the corresponding
Macdonald processes) can be utilized to get $q$-moments of the height function
$\mathfrak{h}$ in the higher spin six vertex model first computed in
arXiv:1601.05770 using Bethe ansatz. This result in particular implies that for
the vertex model with the step Bernoulli boundary condition, the value of
$\mathfrak{h}$ at an arbitrary point
$(N+1,T)\in\mathbb{Z}_{\ge2}\times\mathbb{Z}_{\ge1}$ has the same distribution
as the last component $\lambda_N$ of a random partition under a specific $t=0$
Macdonald measure. On the other hand, it is known that
$\mathbf{x}_N:=\lambda_N-N$ can be identified with the location of the $N$th
particle in a certain discrete time $q$-TASEP started from the step initial
configuration. The second construction we present is a coupling of this
$q$-TASEP and the higher spin six vertex model (with the step Bernoulli
boundary condition) along time-like paths providing an independent
probabilistic explanation of the equality of $\mathfrak{h}(N+1,T)$ and
$\mathbf{x}_N+N$ in distribution. Combined with the identification of averages
of observables between the stochastic higher spin six vertex model and Schur
measures (which are $t=q$ Macdonald measures) obtained recently in
arXiv:1608.01553, this produces GUE Tracy--Widom asymptotics for a discrete
time $q$-TASEP with the step initial configuration and special jump parameters.


title:
Baryon asymmetry via leptogenesis in a neutrino mass model with complex
  scaling

abstract:
  Baryogenesis via leptogenesis is investigated in a specific model of light
neutrino masses and mixing angles. The latter was proposed on the basis of an
assumed complex-extended scaling property of the neutrino Majorana mass matrix
$M_\nu$, derived with a type-1 seesaw from a Dirac mass matrix $m_D$ and a
heavy singlet neutrino Majorana mass matrix $M_R$. One of its important
features, highlighted here, is that there is a common source of the origin of a
nonzero $\theta_{13}$ and the CP violating lepton asymmetry through the
imaginary part of $m_D$. The model predicted CP violation to be maximal for the
Dirac type and vanishing for the Majorana type. We assume strongly hierarchical
mass eigenvalues for $M_R$. The leptonic CP asymmetry parameter
$\varepsilon^\alpha_{1}\hspace{1mm}$ with lepton flavor $\alpha$, originating
from the decays of the lightest of the heavy neutrinos $N_1$ (of mass $M_1$) at
a temperature $T\sim M_1$, is what matters here with
$\varepsilon^\alpha_{2,3}$, originating from the decays of $N_{2,3}$, being
washed out. The light leptonic and heavy neutrino number densities (normalized
to the entropy density) are evolved via Boltzmann equations down to electroweak
temperatures to yield a baryon asymmetry through sphaleronic transitions. The
effect of flavored vs. unflavored leptogenesis in the three mass regimes (1)
$M_1<10^{9}$ GeV, (2) $10^9$ GeV $<M_1<$ $10^{12}$ GeV and (3) $M_1>10^{12}$
GeV are numerically worked out for both a normal and an inverted mass ordering
of the light neutrinos. Corresponding results on the baryon asymmetry of the
universe are obtained, displayed and discussed.


title: Advantage of a lead swimmer in drafting

abstract:
  We present results from model tests to investigate the effect of drafting in
swimming, in particular for the lead swimmer. The drag for scaled-model passive
swimmers was determined accurately at Froude numbers comparable to conditions
for actual human swimmers. Several positions of a draft swimmer at different
separations behind and alongside the lead swimmer were investigated. It was
found that a lead swimmer can experience an advantage from a draft swimmer.
Several other positions of the draft swimmer relative to the frontal wave
generated by the lead swimmer were also considered. These results indicate
favourable and undesirable positions during passing.


title: The noncommutative geometry of Zitterbewegung

abstract:
  Based on the mathematics of noncommutative geometry, we model a 'classical'
Dirac fermion propagating in a curved spacetime. We demonstrate that the
inherent causal structure of the model encodes the possibility of
Zitterbewegung - the 'trembling motion' of the fermion. We recover the
well-known frequency of Zitterbewegung as the highest possible speed of change
in the fermion's 'internal space'. Furthermore, we show that the latter does
not change in the presence of an external electromagnetic field and derive its
explicit analogue when the mass parameter is promoted to a Higgs-like field. We
discuss a table-top experiment in the domain of quantum simulation to test the
predictions of the model and outline the consequences of our model for quantum
gauge theories.

categories: math-ph cond-mat.other gr-qc math.MP quant-ph


title: Likelihood Analysis of Supersymmetric SU(5) GUTs

abstract:
  We perform a likelihood analysis of the constraints from accelerator
experiments and astrophysical observations on supersymmetric (SUSY) models with
SU(5) boundary conditions on soft SUSY-breaking parameters at the GUT scale.
The parameter space of the models studied has 7 parameters: a universal gaugino
mass $m_{1/2}$, distinct masses for the scalar partners of matter fermions in
five- and ten-dimensional representations of SU(5), $m_5$ and $m_{10}$, and for
the $\mathbf{5}$ and $\mathbf{\bar 5}$ Higgs representations $m_{H_u}$ and
$m_{H_d}$, a universal trilinear soft SUSY-breaking parameter $A_0$, and the
ratio of Higgs vevs $\tan \beta$. In addition to previous constraints from
direct sparticle searches, low-energy and flavour observables, we incorporate
constraints based on preliminary results from 13 TeV LHC searches for jets +
MET events and long-lived particles, as well as the latest PandaX-II and LUX
searches for direct Dark Matter detection. In addition to previously-identified
mechanisms for bringing the supersymmetric relic density into the range allowed
by cosmology, we identify a novel ${\tilde u_R}/{\tilde c_R} -
\tilde{\chi}^0_1$ coannihilation mechanism that appears in the supersymmetric
SU(5) GUT model and discuss the role of ${\tilde \nu_\tau}$ coannihilation. We
find complementarity between the prospects for direct Dark Matter detection and
SUSY searches at the LHC.


title:
Persistence Diagrams as Diagrams: A Categorification of the Stability
  Theorem

abstract:
  Persistent homology, a central tool of topological data analysis, provides
invariants of data called barcodes (also known as persistence diagrams). A
barcode is simply a multiset of real intervals. Recent work of Edelsbrunner,
Jablonski, and Mrozek suggests an equivalent description of barcodes as
functors R -> Mch, where R is the poset category of real numbers and Mch is the
category whose objects are sets and whose morphisms are matchings (i.e.,
partial injective functions). Such functors form a category Mch^R whose
morphisms are the natural transformations. Thus, this interpretation of
barcodes gives us a hitherto unstudied categorical structure on barcodes. The
aim of this note is to show that this categorical structure leads to
surprisingly simple reformulations of both the well-known stability theorem for
persistent homology and a recent generalization called the induced matching
theorem.


title: Dynamics of a multicomponent vesicle in shear flow

abstract:
  We study the fully nonlinear, nonlocal dynamics of two-dimensional
multicomponent vesicles in a shear flow with matched viscosity of the inner and
outer fluids. Using a nonstiff, pseudo-spectral boundary integral method, we
investigate dynamical patterns induced by inhomogeneous bending for a two phase
system. Numerical results reveal that there exist novel phase-treading and
tumbling mechanisms that cannot be observed for a homogeneous vesicle. In
particular, unlike the well-known steady tank-treading dynamics characterized
by a fixed inclination angle, here the phase-treading mechanism leads to
unsteady periodic dynamics with an oscillatory inclination angle. When the
average phase concentration is around 1/2, we observe tumbling dynamics even
for very low shear rate, and the excess length required for tumbling is
significantly smaller than the value for the single phase case. We summarize
our results in phase diagrams in terms of the excess length, shear rate, and
concentration of the soft phase. These findings go beyond the well known
dynamical regimes of a homogeneous vesicle and highlight the level of
complexity of vesicle dynamics in a fluid due to heterogeneous material
properties.


title: Tensor Switching Networks

abstract:
  We present a novel neural network algorithm, the Tensor Switching (TS)
network, which generalizes the Rectified Linear Unit (ReLU) nonlinearity to
tensor-valued hidden units. The TS network copies its entire input vector to
different locations in an expanded representation, with the location determined
by its hidden unit activity. In this way, even a simple linear readout from the
TS representation can implement a highly expressive deep-network-like function.
The TS network hence avoids the vanishing gradient problem by construction, at
the cost of larger representation size. We develop several methods to train the
TS network, including equivalent kernels for infinitely wide and deep TS
networks, a one-pass linear learning algorithm, and two
backpropagation-inspired representation learning algorithms. Our experimental
results demonstrate that the TS network is indeed more expressive and
consistently learns faster than standard ReLU networks.


title: Compact Hermitian Young Projection Operators

abstract:
  In this paper, we describe a compact and practical algorithm to construct
Hermitian Young projection operators for irreducible representations of the
special unitary group SU(N), and discuss why ordinary Young projection
operators are unsuitable for physics applications. The proof of this
construction algorithm uses the iterative method described by Keppeler and
Sj\"odahl. We further show that Hermitian Young projection operators share
desirable properties with Young tableaux, namely a nested hierarchy when
"adding a particle". We end by exhibiting the enormous advantage of the
Hermitian Young projection operators constructed in this paper over those given
by Keppeler and Sj\"odahl.


title: Shadows and spirals in the protoplanetary disk HD 100453

abstract:
  Understanding the diversity of planets requires to study the morphology and
the physical conditions in the protoplanetary disks in which they form. We
observed and spatially resolved the disk around the ~10 Myr old protoplanetary
disk HD 100453 in polarized scattered light with SPHERE/VLT at optical and
near-infrared wavelengths, reaching an angular resolution of ~0.02", and an
inner working angle of ~0.09". We detect polarized scattered light up to ~0.42"
(~48 au) and detect a cavity, a rim with azimuthal brightness variations at an
inclination of 38 degrees, two shadows and two symmetric spiral arms. The
spiral arms originate near the location of the shadows, close to the semi major
axis. We detect a faint spiral-like feature in the SW that can be interpreted
as the scattering surface of the bottom side of the disk, if the disk is
tidally truncated by the M-dwarf companion currently seen at a projected
distance of ~119 au. We construct a radiative transfer model that accounts for
the main characteristics of the features with an inner and outer disk
misaligned by ~72 degrees. The azimuthal brightness variations along the rim
are well reproduced with the scattering phase function of the model. While
spirals can be triggered by the tidal interaction with the companion, the close
proximity of the spirals to the shadows suggests that the shadows could also
play a role. The change in stellar illumination along the rim, induces an
azimuthal variation of the scale height that can contribute to the brightness
variations. Dark regions in polarized images of transition disks are now
detected in a handful of disks and often interpreted as shadows due to a
misaligned inner disk. The origin of such a misalignment in HD 100453, and of
the spirals, is unclear, and might be due to a yet-undetected massive companion
inside the cavity, and on an inclined orbit.


title:
Wall-bounded multiphase flows of N immiscible incompressible fluids:
  consistency and contact-angle boundary condition

abstract:
  We present an effective method for simulating wall-bounded multiphase flows
consisting of $N$ ($N\geqslant 2$) immiscible incompressible fluids with
different densities, viscosities and pairwise surface tensions. The N-phase
physical formulation is based on a modified thermodynamically consistent phase
field model that is more general than in a previous work, and it is developed
by considering the reduction consistency if some of the fluid components were
absent from the system. We propose an N-phase contact-angle boundary condition
that is reduction consistent between $N$ phases and $M$ phases ($2\leqslant
M\leqslant N-1$). We also present a numerical algorithm for solving the N-phase
governing equations together with the contact-angle boundary conditions
developed herein. Extensive numerical experiments are presented for several
flow problems involving multiple fluid components and solid-wall boundaries to
investigate the wettability effects with multiple types of contact angles. In
particular, we compare simulation results with the de Gennes theory for the
contact-angle effects on the liquid drop spreading on wall surfaces, and
demonstrate that our method produces physically accurate results.


title: Transient terahertz photoconductivity of insulating cuprates

abstract:
  We establish a detailed phenomenology of photocarrier transport in the copper
oxide plane by studying the transient terahertz photoconductivity of
Sr$_2$CuO$_2$Cl$_2$ and YBa$_2$Cu$_3$O$_6$. The peak photoconductivity
saturates with fluence, decays on multiple picosecond timescales, and evolves
into a state characterized by activated transport. The time dependence shows
little change with fluence, indicating that the decay is governed by
first-order recombination kinetics. We find that most photocarriers make a
negligible contribution to the dc photoconductivity, and we estimate the
intrinsic photocarrier mobility to be 0.6-0.7 cm$^2$/V s at early times,
comparable to the mobility in chemically doped materials.


title: Gravitational waves from pulsars in the context of magnetic ellipticity

abstract:
  In one of our previous articles we have considered the role of a time
dependent magnetic ellipticity on pulsars' braking indices and on the putative
gravitational waves these objects can emit. Since only nine of more than 2000
known pulsars have accurately measured braking indices, it is of interest to
extend this study to all known pulsars, in particular to what concerns the
gravitational waves generation. To do so, as shown in our previous article, we
need to know some pulsars' observable quantities such as: periods and their
time derivatives, and estimated distances to the Earth. Moreover, we also need
to know the pulsars' masses and radii, for which, in here we are adopting
current fiducial values. Our results show that the gravitational wave amplitude
is at best $h \sim 10^{-28}$. This leads to a pessimistic prospect for the
detection of gravitational waves generated by these pulsars, even for Advanced
LIGO and Advanced Virgo, and the planned Einstein Telescope, whether the
ellipticity has magnetic origin.


title: On the isomorphism of tensor powers of ergodic flows

abstract:
  The following question due to Thouvenot is well-known in ergodic theory. Let
$S$ and $T$ be automorphisms of a probability space and let $ S \otimes S $ be
isomorphic to $T \otimes T $. Could $S$ be not isomorphic to $T$? Our note
contains a simple answer to this question and a generalization of Kulaga's
result on the corresponding isomorphism for some class of flows (see
arXiv:1101.4975). We show that the isomorphism of weakly mixing flows $ S_t
\otimes S_t $ and $ T_t \otimes T_t $ implies the isomorphism of the flows
$S_t$ and $T_t$, if the latter has an integral weak limit.


title:
Optical Sky Brightness and Transparency During the Winter Season at Dome
  A Antarctica From the Gattini-Allsky Camera

abstract:
  The summit of the Antarctic plateau, Dome A, is proving to be an excellent
site for optical, NIR, and THz astronomical observations. GATTINI was a
wide-field camera installed on the PLATO instrument module as part of the
Chinese-led traverse to Dome A in January, 2009. We present here the
measurements of sky brightness with the Gattini ultra-large field of view (90
deg x 90 deg) in the photometric B-, V-, and R-bands, cloud cover statistics
measured during the 2009 winter season, and an estimate of the sky
transparency. A cumulative probability distribution indicates that the darkest
10% of the nights at Dome A have sky brightness of S_B = 22.98, S_V = 21.86,
and S_R = 21.68 mag arcsec^{-2}. These values were obtained around the year
2009 with minimum aurora, and they are comparable to the faintest sky
brightness at Mauna Kea and the best sites of northern Chile. Since every
filter includes strong auroral lines that effectively contaminate the sky
brightness measurements, for instruments working around the auroral lines,
either with custom filters or with high spectral resolution instruments, these
values could be easily obtained on a more routine basis. In addition, we
present example light curves for bright targets to emphasize the unprecedented
observational window function available from this ground-based site. These
light curves will be published in a future paper.


title:
A Foreground Masking Strategy for [CII] Intensity Mapping Experiments
  Using Galaxies Selected by Stellar Mass and Redshift

abstract:
  Intensity mapping provides a unique means to probe the epoch of reionization
(EoR), when the neutral intergalactic medium was ionized by the energetic
photons emitted from the first galaxies. The [CII] 158$\mu$m fine-structure
line is typically one of the brightest emission lines of star-forming galaxies
and thus a promising tracer of the global EoR star-formation activity. However,
[CII] intensity maps at $6 \lesssim z \lesssim 8$ are contaminated by
interloping CO rotational line emission ($3 \leq J_{\rm upp} \leq 6$) from
lower-redshift galaxies. Here we present a strategy to remove the foreground
contamination in upcoming [CII] intensity mapping experiments, guided by a
model of CO emission from foreground galaxies. The model is based on empirical
measurements of the mean and scatter of the total infrared luminosities of
galaxies at $z < 3$ and with stellar masses $M_{*} > 10^{8}\,\rm M_{\rm \odot}$
selected in $K$-band from the COSMOS/UltraVISTA survey, which can be converted
to CO line strengths. For a mock field of the Tomographic Ionized-carbon
Mapping Experiment (TIME), we find that masking out the "voxels"
(spectral-spatial elements) containing foreground galaxies identified using an
optimized CO flux threshold results in a $z$-dependent criterion $m^{\rm
AB}_{\rm K} \lesssim 22$ (or $M_{*} \gtrsim 10^{9} \,\rm M_{\rm \odot}$) at $z
< 1$ and makes a [CII]/CO$_{\rm tot}$ power ratio of $\gtrsim 10$ at $k=0.1$
$h$/Mpc achievable, at the cost of a moderate $\lesssim 8\%$ loss of total
survey volume.


title: Landau gauge gluon vertices from Lattice QCD

abstract:
  In lattice QCD the computation of one-particle irreducible (1PI) Green's
functions with a large number (> 2) of legs is a challenging task. Besides
tuning the lattice spacing and volume to reduce finite size effects, the
problems associated with the estimation of higher order moments via Monte Carlo
methods and the extraction of 1PI from complete Green's functions are
limitations of the method. Herein, we address these problems revisiting the
calculation of the three gluon 1PI Green's function.


title: Simulations of N=1 supersymmetric Yang-Mills theory with three colours

abstract:
  We report on our recent results regarding numerical simulations of the four
dimensional, N=1 Supersymmetric Yang-Mills theory with SU(3) gauge symmetry and
light dynamical gluinos.


title:
Stochastic Faraday rotation induced by the electric current fluctuations
  in nanosystems

abstract:
  We demonstrate theoretically that in gyrotropic semiconductors and
semiconductor nanosystems the Brownian motion of electrons results in temporal
fluctuations of the polarization plane of light passing through or reflected
from the structure, i.e., in stochastic Faraday or Kerr rotation effects. The
theory of the effects is developed for a number of prominent gyrotropic systems
such as bulk tellurium, ensembles of chiral carbon nanotubes, and GaAs-based
quantum wells of different crystallographic orientations. We show that the
power spectrum of these fluctuations in thermal equilibrium is proportional to
the ac conductivity of the system. We evaluate contributions resulting from the
fluctuations of the electric current, as well as of spin, valley polarization,
and the spin current to the noise of the Faraday/Kerr rotation. Hence,
all-optical measurements of the Faraday and Kerr rotation noise provide an
access to the transport properties of the semiconductor systems.


title: Neural Machine Translation in Linear Time

abstract:
  We present a novel neural network for processing sequences. The ByteNet is a
one-dimensional convolutional neural network that is composed of two parts, one
to encode the source sequence and the other to decode the target sequence. The
two network parts are connected by stacking the decoder on top of the encoder
and preserving the temporal resolution of the sequences. To address the
differing lengths of the source and the target, we introduce an efficient
mechanism by which the decoder is dynamically unfolded over the representation
of the encoder. The ByteNet uses dilation in the convolutional layers to
increase its receptive field. The resulting network has two core properties: it
runs in time that is linear in the length of the sequences and it sidesteps the
need for excessive memorization. The ByteNet decoder attains state-of-the-art
performance on character-level language modelling and outperforms the previous
best results obtained with recurrent networks. The ByteNet also achieves
state-of-the-art performance on character-to-character machine translation on
the English-to-German WMT translation task, surpassing comparable neural
translation models that are based on recurrent networks with attentional
pooling and run in quadratic time. We find that the latent alignment structure
contained in the representations reflects the expected alignment between the
tokens.


title: Homogeneous Atomic Fermi Gases

abstract:
  We report on the creation of homogeneous Fermi gases of ultracold atoms in a
uniform potential. In the momentum distribution of a spin-polarized gas, we
observe the emergence of the Fermi surface and the saturated occupation of one
particle per momentum state. This directly confirms Pauli blocking in momentum
space. For the spin-balanced unitary Fermi gas, we observe spatially uniform
pair condensates. For thermodynamic measurements, we introduce a hybrid
potential that is harmonic in one dimension and uniform in the other two. The
spatially resolved compressibility reveals the superfluid transition in a
spin-balanced Fermi gas, saturation in a fully polarized Fermi gas, and strong
attraction in the polaronic regime of a partially polarized Fermi gas.


title:
The Most General Form of Deformation of the Heisenberg Algebra from the
  Generalized Uncertainty Principle

abstract:
  In this paper, we will propose the most general form of the deformation of
Heisenberg algebra motivated by the generalized uncertainty principle. This
deformation of the Heisenberg algebra will deform all quantum mechanical
systems. The form of the generalized uncertainty principle used to motivate
these results will be motivated by space fractional quantum mechanics and
non-locality in quantum mechanical systems. We also analyse a specific limit of
this generalized deformation for one dimensional system, and in that limit, a
nonlocal deformation of the momentum operator generates a local deformation of
all one dimensional quantum mechanical systems. We analyse the low energy
effects of this deformation on a harmonic oscillator, Landau levels, Lamb
shift, and potential barrier. We also demonstrate that this deformation leads
to a discretization of space.


title:
ALMA observations of the dense and shocked gas in the nuclear region of
  NGC 4038 (Antennae galaxies)

abstract:
  We present 1" (<100 pc) resolution maps of millimeter emission from five
molecules-CN, HCN, HCO+, CH3OH, and HNCO-obtained towards NGC 4038, which is
the northern galaxy of the mid-stage merger, Antennae galaxies, with the
Atacama Large Millimeter/submillimeter Array. Three molecules (CN, CH3OH, and
HNCO) were detected for the first time in the nuclear region of NGC 4038.
High-resolution mapping reveals a systematic difference in distributions of
different molecular species and continuum emission. Active star forming regions
identified by the 3 mm and 850 um continuum emission are offset from the
gas-rich region associated with the HCN (1-0) and CO (3-2) peaks. The CN
(1-0)/HCN (1-0) line ratios are enhanced (CN/HCN = 0.8-1.2) in the star forming
regions, suggesting that the regions are photon dominated. The large molecular
gas mass (10^8 Msun) within a 0.6" (~60 pc) radius of the CO (3-2) peak and a
high dense gas fraction (>20 %) suggested by the HCN (1-0)/CO (3-2) line ratio
may signify a future burst of intense star formation there. The shocked gas
traced in the CH3OH and HNCO emission indicates sub-kpc scale molecular shocks.
We suggest that the molecular shocks may be driven by collisions between
inflowing gas and the central massive molecular complex.


title: Quantum chaos on a critical Fermi surface

abstract:
  We compute parameters characterizing many-body quantum chaos for a critical
Fermi surface without quasiparticle excitations. We examine a theory of $N$
species of fermions at non-zero density coupled to a $U(1)$ gauge field in two
spatial dimensions, and determine the Lyapunov rate and the butterfly velocity
in an extended random-phase approximation. The thermal diffusivity is found to
be universally related to these chaos parameters i.e. the relationship is
independent of $N$, the gauge coupling constant, the Fermi velocity, the Fermi
surface curvature, and high energy details.


title:
Hydrogen Emission from the Ionized Gaseous Halos of Low Redshift
  Galaxies

abstract:
  Using a sample of nearly half million galaxies, intersected by over 7 million
lines of sight from the Sloan Digital Sky Survey Data Release 12, we trace
H$\alpha$ + [N{\small II}] emission from a galactocentric projected radius,
$r_p$, of 5 kpc to more than 100 kpc. The emission flux surface brightness is
$\propto r_p^{-1.9 \pm 0.4}$. We obtain consistent results using only the
H$\alpha$ or [N{\small II}] flux. We measure a stronger signal for the bluer
half of the target sample than for the redder half on small scales, $r_p <$ 20
kpc. We obtain a $3\sigma$ detection of H$\alpha$ + [N{\small II}] emission in
the 50 to 100 kpc $r_p$ bin. The mean emission flux within this bin is $(1.10
\pm 0.35) \times 10^{-20}$ erg cm$^{-2}$ s$^{-1}$ \AA$^{-1}$, which corresponds
to $1.87 \times 10^{-20}$ erg cm$^{-2}$ s$^{-1}$ arcsec$^{-2}$ or 0.0033
Rayleigh. This detection is 34 times fainter than a previous strict limit
obtained using deep narrow-band imaging. The faintness of the signal
demonstrates why it has been so difficult to trace recombination radiation out
to large radii around galaxies. This signal, combined with published estimates
of n$_{\rm H}$, lead us to estimate the temperature of the gas to be 12,000 K,
consistent with independent empirical estimates based on metal ion absorption
lines and expectations from numerical simulations.


title:
Addressing the too big to fail problem with baryon physics and sterile
  neutrino dark matter

abstract:
  N-body dark matter simulations of structure formation in the $\Lambda$CDM
model predict a population of subhalos within Galactic halos that have higher
central densities than inferred for satellites of the Milky Way, a tension
known as the `too big to fail' problem. Proposed solutions include baryonic
effects, a smaller mass for the Milky Way halo, and warm dark matter. We test
these three possibilities using a semi-analytic model of galaxy formation to
generate luminosity functions for Milky Way halo-analogue satellite
populations, the results of which are then coupled to the Jiang & van den Bosch
model of subhalo stripping to predict the subhalo $V_\mathrm{max}$ functions
for the 10 brightest satellites. We find that selecting the brightest
satellites (as opposed to the most massive) and modelling the expulsion of gas
by supernovae at early times increases the likelihood of generating the
observed Milky Way satellite $V_\mathrm{max}$ function. The preferred halo mass
is $6\times10^{11}M_{\odot}$, which has a 14 percent probability to host a
$V_\mathrm{max}$ function like that of the Milky Way satellites. This
probability is reduced to 8 percent for a $1.0\times10^{12}M_{\odot}$ halo and
to 3 percent for a $1.4\times10^{12}M_{\odot}$ halo. We conclude that the Milky
Way satellite $V_\mathrm{max}$ function is compatible with a CDM cosmology, as
previously found by Sawala et al. using hydrodynamic simulations. Sterile
neutrino-warm dark matter models achieve a higher degree of agreement with the
observations, with a maximum 35 percent chance of generating the observed Milky
Way satellite $V_\mathrm{max}$ function. However, more work is required to
check that the semi-analytic stripping model is calibrated correctly in the
sterile neutrino cosmology, and to check if our sterile neutrino models produce
sufficient numbers of faint satellites.


title:
Star Formation in Ultraluminous Infrared Galaxies Probed with AKARI
  Near-Infrared Spectroscopy

abstract:
  We conducted systematic observations of the HI Br-alpha line (4.05 micron)
and the polycyclic aromatic hydrocarbon (PAH) feature (3.3 micron) in 50 nearby
(z<0.3) ultraluminous infrared galaxies (ULIRGs) with AKARI. The Br-alpha line
is predicted to be the brightest among the HI lines under high dust-extinction
conditions (A_V>15 mag). The Br-alpha line traces ionizing photons from OB
stars and so is used as an indicator of star formation on the assumption of the
initial mass function. We detected the Br-alpha line in 33 ULIRGs. The
luminosity of the line (L_BrA) correlates well with that of the 3.3 micron PAH
emission (L_3.3). Thus we utilize L_3.3 as an indicator of star formation in
fainter objects where the Br-alpha line is undetected. The mean L_BrA/L_IR
ratio in LINERs/Seyferts is significantly lower than that in HII galaxies. This
difference is reconfirmed with the L_3.3/L_IR ratio in the larger sample (46
galaxies). Using the ratios, we estimate that the contribution of starburst in
LINERs/Seyferts is ~67%, and active galactic nuclei contribute to the remaining
~33%. However, comparing the number of ionizing photons, Q_BrA, derived from
L_BrA with that, Q_IR, expected from star formation rate required to explain
L_IR, we find that the mean Q_BrA/Q_IR ratio is only 55.5+/-7.5% even in HII
galaxies which are thought to be energized by pure starburst. This deficit of
ionizing photons traced by the Br-alpha line is significant even taking heavy
dust extinction into consideration. We propose that dust within HII regions
absorbs a significant fraction of ionizing photons.


title:
The unstable fate of the planet orbiting the A-star in the HD 131399
  triple stellar system

abstract:
  Validated planet candidates need not lie on long-term stable orbits, and
instability triggered by post-main-sequence stellar evolution can generate
architectures which transport rocky material to white dwarfs, polluting them.
The giant planet HD 131399Ab orbits its parent A star at a projected separation
of about 50-100 au. The host star, HD 131399A, is part of a hierarchical triple
with HD 131399BC being a close binary separated by a few hundred au from the A
star. Here, we determine the fate of this system, and find that (i) stability
along the main sequence is achieved only for a favourable choice of parameters
within the errors, and (ii) even for this choice, in almost every instance the
planet is ejected during the transition between the giant branch and white
dwarf phases of HD 131399A. This result provides an example of both how the
free-floating planet population may be enhanced by similar systems, and how
instability can manifest in the polluted white dwarf progenitor population.


title: Red nuggets grow inside-out: evidence from gravitational lensing

abstract:
  We present a new sample of strong gravitational lens systems where both the
foreground lenses and background sources are early-type galaxies. Using imaging
from HST/ACS and Keck/NIRC2, we model the surface brightness distributions and
show that the sources form a distinct population of massive, compact galaxies
at redshifts $0.4 \lesssim z \lesssim 0.7$, lying systematically below the
size-mass relation of the global elliptical galaxy population at those
redshifts. These may therefore represent relics of high-redshift red nuggets or
their partly-evolved descendants. We exploit the magnifying effect of lensing
to investigate the structural properties, stellar masses and stellar
populations of these objects with a view to understanding their evolution. We
model these objects parametrically and find that they generally require two
S\'ersic components to properly describe their light profiles, with one more
spheroidal component alongside a more envelope-like component, which is
slightly more extended though still compact. This is consistent with the
hypothesis of the inside-out growth of these objects via minor mergers. We also
find that the sources can be characterised by red-to-blue colour gradients as a
function of radius which are stronger at low redshift -- indicative of ongoing
accretion -- but that their environments generally appear consistent with that
of the general elliptical galaxy population, contrary to recent suggestions
that these objects are predominantly associated with clusters.


title: Radiative Yukawa Couplings in the Simplest Left-Right Symmetric Model

abstract:
  We revisit a recent solution to the flavor hierarchy problem based on the
paradigm that Yukawa couplings are, rather than fundamental constants,
effective low energy couplings radiatively generated by interactions in a
hidden sector of the theory. In the present paper we show that the setup
required by this scenario can be set by gauge invariance alone, provided that
the Standard Model gauge group be extended to the left-right symmetric group of
$SU(2)_L\times SU(2)_R\times U(1)_Y$. The simplest scheme in which Yukawa
couplings are forbidden at the tree-level organises the right-handed fermions
into doublets and presents an additional Higgs $SU(2)_R$ doublet, responsible
for the spontaneous breaking of the $SU(2)_R$ gauge sector. The flavor and
chiral symmetry breaking induced by the $SU(2)_R$ breaking is transferred at
the one-loop level to the Standard Model via the dynamics of the hidden sector,
which effectively regulates the spread of the effective Yukawa couplings. The
emerging left-right symmetric framework recovers additional appealing features
typical of these models, allowing for instance to identify the hypercharges of
the involved fermions with their $B-L$ charges and offering a straightforward
solution to the strong CP problem. The scheme gives rise to a distinguishing
phenomenology that potentially can be tested at the LHC and future colliders
through the same interactions that result in the radiative generation of Yukawa
couplings, as well as by exploiting the properties of the additional $SU(2)_R$
Higgs doublet.


title:
Properties of Local Group galaxies in hydrodynamical simulations of
  sterile neutrino dark matter cosmologies

abstract:
  We study galaxy formation in sterile neutrino dark matter models that differ
signifi- cantly from both cold and from `warm thermal relic' models. We use the
EAGLE code to carry out hydrodynamic simulations of the evolution of pairs of
galaxies chosen to resemble the Local Group, as part of the APOSTLE simulations
project. We compare cold dark matter (CDM) with two sterile neutrino models
with 7 keV mass: one, the warmest among all models of this mass (LA120) and the
other, a relatively cold case (LA10). We show that the lower concentration of
sterile neutrino subhalos compared to their CDM counterparts makes the inferred
inner dark matter content of galaxies like Fornax (or Magellanic Clouds) less
of an outlier in the sterile neutrino cosmologies. In terms of the galaxy
number counts the LA10 simulations are indistinguishable from CDM when one
takes into account halo-to-halo (or `simulation-to-simulation') scatter. In
order for the LA120 model to match the number of Local Group dwarf galaxies, a
higher fraction of low mass haloes is required to form galaxies than is
predicted by the EAGLE simulations. As the census of the Local Group galaxies
nears completion, this population may provide a strong discriminant between
cold and warm dark matter models.


title: Switchable topological phonon channels

abstract:
  Guiding energy deliberately is one of the central elements in engineering and
information processing. It is often achieved by designing specific transport
channels in a suitable material. Topological metamaterials offer a way to
construct stable and efficient channels of unprecedented versatility. However,
due to their stability it can be tricky to terminate them or to temporarily
shut them off without changing the material properties massively. While a lot
of effort was put into realizing mechanical topological metamaterials, almost
no works deal with manipulating their edge channels in sight of applications.
Here, we take a step in this direction, by taking advantage of local symmetry
breaking potentials to build a switchable topological phonon channel.


title:
Decimetre-scaled spectrophotometric properties of the nucleus of comet
  67P/Churyumov-Gerasimenko from OSIRIS observations

abstract:
  We present the results of the photometric and spectrophotometric properties
of the 67P/Churyumov-Gerasimenko nucleus derived with the OSIRIS instrument
during the closest fly-by over the comet, which took place on 14 th February
2015 at a distance of {\~} 6 km from the surface. Several images covering the
0{\deg}-33{\deg} phase angle range were acquired, and the spatial resolution
achieved was 11 cm/pxl. The flown-by region is located on the big lobe of the
comet, near the borders of the Ash, Apis and Imhotep regions. Our analysis
shows that this region features local heterogeneities at the decimetre scale.
We observed difference of reflectance up to 40{\%} between bright spots and
sombre regions, and spectral slope variations up to 50{\%}. The spectral
reddening effect observed globally on the comet surface by Fornasier et al.
(2015) is also observed locally on this region, but with a less steep
behaviour. We note that numerous metre-sized boulders, which exhibit a smaller
opposition effect, also appear spectrally redder than their surroundings. In
this region, we found no evidence linking observed bright spots to exposed
water-ice-rich material. We fitted our dataset using the Hapke 2008 photometric
model. The region overflown is globally as dark as the whole nucleus (geometric
albedo of 6.8{\%}) and it has a high porosity value in the uppermost-layers
(86{\%}). These results of the photometric analysis at a decimetre scale
indicate that the photometric properties of the flown-by region are similar to
those previously found for the whole nucleus.


title: A framework for second-order parton showers

abstract:
  A framework is presented for including second-order perturbative corrections
to the radiation patterns of parton showers. The formalism allows to combine
O(alphaS^2)-corrected iterated 2->3 kernels for "ordered" gluon emissions with
tree-level 2->4 kernels for "unordered" ones. The combined Sudakov evolution
kernel is thus accurate to O(alphaS^2). As a first step towards a full-fledged
implementation of these ideas, we develop an explicit implementation of 2->4
shower branchings in this letter.


title: iPTF16geu: A multiply imaged, gravitationally lensed type Ia supernova

abstract:
  We report the discovery of a multiply-imaged gravitationally lensed Type Ia
supernova, iPTF16geu (SN 2016geu), at redshift $z=0.409$. This phenomenon could
be identified because the light from the stellar explosion was magnified more
than fifty times by the curvature of space around matter in an intervening
galaxy. We used high spatial resolution observations to resolve four images of
the lensed supernova, approximately 0.3" from the center of the foreground
galaxy. The observations probe a physical scale of $\sim$1 kiloparsec, smaller
than what is typical in other studies of extragalactic gravitational lensing.
The large magnification and symmetric image configuration implies close
alignment between the line-of-sight to the supernova and the lens. The relative
magnifications of the four images provide evidence for sub-structures in the
lensing galaxy.


title:
Searching for Planet Nine with Coadded WISE and NEOWISE-Reactivation
  Images

abstract:
  A distant, as yet unseen ninth planet has been invoked to explain various
observations of the outer solar system. While such a 'Planet Nine', if it
exists, is most likely to be discovered via reflected light in the optical, it
may emit much more strongly at 3$-$5$\mu$m than simple blackbody predictions
would suggest, depending on its atmospheric properties (Fortney et al. 2016).
As a result, Planet Nine may be detectable at 3.4$\mu$m with WISE, but single
exposures are too shallow except at relatively small distances ($d_9 \lesssim
430$ AU). We develop a method to search for Planet Nine far beyond the W1
single-exposure sensitivity, to distances as large as 800 AU, using inertial
coadds of W1 exposures binned into $\sim$1 day intervals. We apply our
methodology to $\sim$2000 square degrees of sky identified by Holman & Payne
(2016) as a potentially likely Planet Nine location, based on the Fienga et al.
(2016) Cassini ranging analysis. We do not detect a plausible Planet Nine
candidate, but are able to derive a detailed completeness curve, ruling out its
presence within the parameter space searched at $W1 < 16.66$ (90%
completeness). Our method uses all publicly available W1 imaging, spanning 2010
January to 2015 December, and will become more sensitive with future
NEOWISE-Reactivation releases of additional W1 exposures. We anticipate that
our method will be applicable to the entire high Galactic latitude sky, and we
will extend our search to that full footprint in the near future.


title: Relative entropy and the RG flow

abstract:
  We consider the relative entropy between vacuum states of two different
theories: a conformal field theory (CFT), and the CFT perturbed by a relevant
operator. By restricting both states to the null Cauchy surface in the causal
domain of a sphere, we make the relative entropy equal to the difference of
entanglement entropies. As a result, this difference has the positivity and
monotonicity properties of relative entropy. From this it follows a simple
alternative proof of the c-theorem in d=2 space-time dimensions and, for d>2,
the proof that the coefficient of the area term in the entanglement entropy
decreases along the renormalization group (RG) flow between fixed points. We
comment on the regimes of convergence of relative entropy, depending on the
space-time dimensions and the conformal dimension $\Delta$ of the perturbation
that triggers the RG flow.


title:
ALMA observations of massive molecular gas filaments encasing radio
  bubbles in the Phoenix cluster

abstract:
  We report new ALMA observations of the CO(3-2) line emission from the
$2.1\pm0.3\times10^{10}\rm\thinspace M_{\odot}$ molecular gas reservoir in the
central galaxy of the Phoenix cluster. The cold molecular gas is fuelling a
vigorous starburst at a rate of $500-800\rm\thinspace M_{\odot}\rm\; yr^{-1}$
and powerful black hole activity in the form of both intense quasar radiation
and radio jets. The radio jets have inflated huge bubbles filled with
relativistic plasma into the hot, X-ray atmospheres surrounding the host
galaxy. The ALMA observations show that extended filaments of molecular gas,
each $10-20\rm\; kpc$ long with a mass of several billion solar masses, are
located along the peripheries of the radio bubbles. The smooth velocity
gradients and narrow line widths along each filament reveal massive, ordered
molecular gas flows around each bubble, which are inconsistent with
gravitational free-fall. The molecular clouds have been lifted directly by the
radio bubbles, or formed via thermal instabilities induced in low entropy gas
lifted in the updraft of the bubbles. These new data provide compelling
evidence for close coupling between the radio bubbles and the cold gas, which
is essential to explain the self-regulation of feedback. The very feedback
mechanism that heats hot atmospheres and suppresses star formation may also
paradoxically stimulate production of the cold gas required to sustain feedback
in massive galaxies.


title: More On Cosmological Gravitational Waves And Their Memories

abstract:
  We extend recent theoretical results on the propagation of linear
gravitational waves (GWs), including their associated memories, in spatially
flat Friedmann--Lema\^{i}tre--Robertson--Walker (FLRW) universes, for all
spacetime dimensions higher than 3. By specializing to a cosmology driven by a
perfect fluid with a constant equation-of-state $w$ -- conformal re-scaling,
dimension-reduction and Nariai's ansatz may then be exploited to obtain
analytic expressions for the graviton and photon Green's functions, allowing
their causal structure to be elucidated. When $0 < w \leq 1$, the
gauge-invariant scalar mode admits wave solutions, and like its tensor
counterpart, likely contributes to the tidal squeezing and stretching of the
space around a GW detector. In addition, scalar GWs in 4D radiation dominated
universes -- like tensor GWs in 4D matter dominated ones -- appear to yield a
tail signal that does not decay with increasing spatial distance from the
source. We then solve electromagnetism in the same cosmologies, and point out a
tail-induced electric memory effect. Finally, in even dimensional Minkowski
backgrounds higher than 2, we make a brief but explicit comparison between the
linear GW memory generated by point masses scattering off each other on unbound
trajectories and the linear Yang-Mills memory generated by color point charges
doing the same -- and point out how there is a "double copy" relation between
the two.


title: Overcoming strong metastabilities with the LLR method

abstract:
  In previous work, it has been shown that the recently proposed LLR method is
very efficient at overcoming strong metastabilities that arise near first-order
phase transition points. Here we present a systematic study of the performance
of the algorithm near (pseudo-)critical points for $q$-state Potts models with
$q$ as large as 20, in two and three dimensions. In particular, we shall focus
our study on the ergodicity of the replica exchange step and the underlying
physical mechanism. When compared with both analytical and numerical results
present in the literature, our determinations of thermodynamic observables
(including the order-disorder interface tension at criticality) show an
impressive degree of relative accuracy (up to $2.5 \times 10^{-6}$), which
confirms the reliability and the efficiency of the proposed approach.


title:
Neural Symbolic Machines: Learning Semantic Parsers on Freebase with
  Weak Supervision

abstract:
  Harnessing the statistical power of neural networks to perform language
understanding and symbolic reasoning is difficult, when it requires executing
efficient discrete operations against a large knowledge-base. In this work, we
introduce a Neural Symbolic Machine, which contains (a) a neural "programmer",
i.e., a sequence-to-sequence model that maps language utterances to programs
and utilizes a key-variable memory to handle compositionality (b) a symbolic
"computer", i.e., a Lisp interpreter that performs program execution, and helps
find good programs by pruning the search space. We apply REINFORCE to directly
optimize the task reward of this structured prediction problem. To train with
weak supervision and improve the stability of REINFORCE, we augment it with an
iterative maximum-likelihood training process. NSM outperforms the
state-of-the-art on the WebQuestionsSP dataset when trained from
question-answer pairs only, without requiring any feature engineering or
domain-specific knowledge.


title: Light dynamics in nonlinear trimers and twisted multicore fibers

abstract:
  Novel photonic structures such as multi-core fibers and graphene based arrays
present unique opportunities to manipulate and control the propagation of
light. Here we discuss nonlinear dynamics for structures with a few (2 to 6)
elements for which linear and nonlinear properties can be tuned. Specifically
we show how nonlinearity, coupling, and parity-time PT symmetric gain/loss
relate to existence, stability and in general, dynamical properties of
nonlinear optical modes. The main emphasis of our presentation will be on
systems with few degrees of freedom, most notably couplers, trimers and
generalizations thereof to systems with 6 nodes.


title: Hypercubic Effects in semileptonic $D \to \pi$ decays on the lattice

abstract:
  We present a lattice determination of the vector and scalar form factors of
the semileptonic $D \to \pi \ell \nu$ decays, which are relevant for the
extraction of the CKM matrix element $\lvert V_{cd} \rvert$ from experimental
data. Our analysis is based on the gauge configurations produced by the
European Twisted Mass Collaboration with $N_f = 2 + 1 + 1$ flavors of dynamical
quarks. We simulated at three different values of the lattice spacing and with
pion masses as small as 210 MeV. Quark momenta are injected on the lattice
using non-periodic boundary conditions. The matrix elements of both vector and
scalar currents are determined for a plenty of kinematical conditions in which
parent and child mesons are either moving or at rest. Lorentz symmetry breaking
due to hypercubic effects is clearly observed in the data and included in the
decomposition of the current matrix elements in terms of additional form
factors. Our preliminary estimate for the vector form factor at zero 4-momentum
transfer is $f_+^{D \to \pi}(0) = 0.631\,(40)$, which can be compared with the
latest FLAG average $f_+^{D \to \pi}(0) = 0.666\,(29)$ available only at $N_f =
2 + 1$.


title: Bridging global and local quantum quenches in conformal field theories

abstract:
  Entanglement evolutions after a global quantum quench and a local quantum
quench in 1+1 dimensional conformal field theories (CFTs) show qualitatively
different behaviors, and are studied within two different setups. In this work,
we bridge global and local quantum quenches in (1+1)-d CFTs in the same setup,
by studying the entanglement evolution from a specific inhomogeneous initial
state. By utilizing conformal mappings, this inhomogeneous quantum quench is
analytically solvable. It is found that the entanglement evolution shows a
global quantum quench feature in the short time limit, and a local quantum
quench feature in the long time limit. The same features are observed in
single-point correlation functions of primary fields. We provide a clear
physical picture for the underlying reason.


title:
Symmetry, Outer Bounds, and Code Constructions: A Computer-Aided
  Investigation on the Fundamental Limits of Caching

abstract:
  We illustrate how computer-aided methods can be used to investigate the
fundamental limits of the caching systems, which are significantly different
from the conventional analytical approach usually seen in the information
theory literature. The linear programming (LP) outer bound of the entropy space
serves as the starting point of this approach; however, our effort goes
significantly beyond using it to prove information inequalities. We first
identify and formalize the symmetry structure in the problem, which enables us
to show the existence of optimal symmetric solutions. A symmetry-reduced linear
program is then used to identify the boundary of the memory-transmission-rate
tradeoff for several small cases, for which we obtain a set of tight outer
bounds. General hypotheses on the optimal tradeoff region are formed from these
computed data, which are then analytically proven. This leads to a complete
characterization of the optimal tradeoff for systems with only two users, and
certain partial characterization for systems with only two files. Next, we show
that by carefully analyzing the joint entropy structure of the outer bounds for
certain cases, a novel code construction can be reverse-engineered, which
eventually leads to a general class of codes. Finally, we show that outer
bounds can be computed through strategically relaxing the LP in different ways,
which can be used to explore the problem computationally. This allows us
firstly to deduce generic characteristic of the converse proof, and secondly to
compute outer bounds for larger problem cases, despite the seemingly impossible
computation scale.


title:
Following The Cosmic Evolution Of Pristine Gas I: Implications For Milky
  Way Halo Stars

abstract:
  We make use of new subgrid model of turbulent mixing to accurately follow the
cosmological evolution of the first stars, the mixing of their supernova
ejecta, and the impact on the chemical composition of the Galactic Halo. Using
the cosmological adaptive mesh refinement code RAMSES, we implement a model for
the pollution of pristine gas as described in Pan et al. Tracking the
metallicity of Pop III stars with metallicities below a critical value allows
us to account for the fraction of Z < Zcrit stars formed even in regions in
which the gas' average metallicity is well above Zcrit. We demonstrate that
such partially-mixed regions account for 0.5 to 0.7 of all Pop III stars formed
up to z = 5. Additionally, we track the creation and transport of "primordial
metals" (PM) generated by Pop III supernovae (SNe). These neutron-capture
deficient metals are taken up by second-generation stars and likely lead to
unique abundance signatures characteristic of carbon-enhanced, metal-poor
(CEMP-no) stars. As an illustrative example, we associate primordial metals
with abundance ratios used by Keller et al. to explain the source of metals in
the star SMSS J031300.36-670839.3, finding good agreement with the observed
[Fe/H], [C/H], [O/H], and [Mg/Ca] ratios in CEMP-no Milky Way halo stars.
Similar future simulations will aid in further constraining the properties of
Pop III stars using CEMP observations, as well as improve predictions of the
spatial distribution of Pop III stars, as will be explored by the next
generation of ground- and space-based telescopes.


title: Extended Galilean symmetries of non-relativistic strings

abstract:
  We consider two non-relativistic strings and their Galilean symmetries. These
strings are obtained as the two possible non-relativistic (NR) limits of a
relativistic string. One of them is non-vibrating and represents a continuum of
non-relativistic massless particles, and the other one is a non-relativistic
vibrating string.
  For both cases we write the generator of the most general point
transformation and impose the condition of Noether symmetry. As a result we
obtain two sets of non-relativistic Killing equations for the vector fields
that generate the symmetry transformations. Solving these equations shows that
NR strings exhibit two extended, infinite dimensional space-time symmetries
which contain, as a subset, the Galilean symmetries. For each case, we compute
the associated conserved charges and discuss the existence of non-central
extensions.


title: CBAS: context based arabic stemmer

abstract:
  Arabic morphology encapsulates many valuable features such as word root.
Arabic roots are being utilized for many tasks; the process of extracting a
word root is referred to as stemming. Stemming is an essential part of most
Natural Language Processing tasks, especially for derivative languages such as
Arabic. However, stemming is faced with the problem of ambiguity, where two or
more roots could be extracted from the same word. On the other hand,
distributional semantics is a powerful co-occurrence model. It captures the
meaning of a word based on its context. In this paper, a distributional
semantics model utilizing Smoothed Pointwise Mutual Information (SPMI) is
constructed to investigate its effectiveness on the stemming analysis task. It
showed an accuracy of 81.5%, with a at least 9.4% improvement over other
stemmers.


title: A Note On One Realization of a Scalable Shor Algorithm

abstract:
  Very recently, Monz, et al. [arXiv:1507.08852] have reported the
demonstration of factoring 15 using a scalable Shor algorithm with an ion-trap
quantum computer. In this note, we remark that the report is somewhat
misleading because there are three flaws in the proposed circuit diagram of
Shor algorithm. We also remark that the principles behind the demonstration
have not been explained properly, including its correctness and complexity.


title:
A Simple Hash Class with Strong Randomness Properties in Graphs and
  Hypergraphs

abstract:
  We study randomness properties of graphs and hypergraphs generated by simple
hash functions. Several hashing applications can be analyzed by studying the
structure of $d$-uniform random ($d$-partite) hypergraphs obtained from a set
$S$ of $n$ keys and $d$ randomly chosen hash functions $h_1,\dots,h_d$ by
associating each key $x\in S$ with a hyperedge $\{h_1(x),\dots, h_d(x)\}$.
Often it is assumed that $h_1,\dots,h_d$ exhibit a high degree of independence.
We present a simple construction of a hash class whose hash functions have
small constant evaluation time and can be stored in sublinear space. We devise
general techniques to analyze the randomness properties of the graphs and
hypergraphs generated by these hash functions, and we show that they can
replace other, less efficient constructions in cuckoo hashing (with and without
stash), the simulation of a uniform hash function, the construction of a
perfect hash function, generalized cuckoo hashing and different load balancing
scenarios.


title:
A Mixture of Linear-Linear Regression Models for Linear-Circular
  Regression

abstract:
  We introduce a new approach to a linear-circular regression problem that
relates multiple linear predictors to a circular response. We follow a modeling
approach of a wrapped normal distribution that describes angular variables and
angular distributions and advances it for a linear-circular regression
analysis. Some previous works model a circular variable as projection of a
bivariate Gaussian random vector on the unit square, and the statistical
inference of the resulting model involves complicated sampling steps. The
proposed model treats circular responses as the result of the modulo operation
on unobserved linear responses. The resulting model is a mixture of multiple
linear-linear regression models. We present two EM algorithms for maximum
likelihood estimation of the mixture model, one for a parametric model and
another for a non-parametric model. The estimation algorithms provide a great
trade-off between computation and estimation accuracy, which was numerically
shown using five numerical examples. The proposed approach was applied to a
problem of estimating wind directions that typically exhibit complex patterns
with large variation and circularity.


title:
Upper Critical Field and Kondo Effects in Fe(Te0.9Se0.1) Thin Films by
  Pulsed Field Measurements

abstract:
  The transition temperatures of epitaxial films of Fe(Te0:9Se0:1) are
remarkably insensitive to applied magnetic field, leading to predictions of
upper critical fields Bc2(T = 0) in excess of 100 T. Using pulsed magnetic
fields, we find Bc2(0) to be on the order of 45 T, similar to values in bulk
material and still in excess of the paramagnetic limit. The same films show
strong magnetoresistance in fields above Bc2(T), consistent with the observed
Kondo minimum seen above Tc. Fits to the temperature dependence in the context
of the WHH model, using the experimental value of the Maki parameter, require
an effective spin-orbit relaxation parameter of order unity. We suggest that
Kondo localization plays a similar role to spin-orbit pair breaking in making
WHH fits to the data.


title: On Lepton-Number-Violating Searches for Muon to Positron Conversion

abstract:
  There is no guarantee that the violation of lepton number, assuming it
exists, will primarily manifest itself in neutrinoless double beta decay
($0\nu\beta\beta$). Lepton-number violation and lepton-flavor violation may be
related, and much-needed information regarding the physics that violates lepton
number can be learned by exploring observables that violate lepton flavors
other than electron flavor. One of the most promising observables is $\mu^-
\rightarrow e^+$ conversion, which can be explored by experiments that are
specifically designed to search for $\mu^- \rightarrow e^-$ conversion. We
survey lepton-number-violating dimension-five, -seven, and -nine effective
operators in the standard model and discuss the relationships between Majorana
neutrino masses and the rates for $0\nu\beta\beta$ and $\mu^- \rightarrow e^+$
conversion. While $0\nu\beta\beta$ has the greatest sensitivity to new
ultraviolet energy scales, its rate might be suppressed by the new physics
relationship to lepton flavor, and $\mu^- \rightarrow e^+$ conversion offers a
complementary probe of lepton-number-violating physics.


title: Wavelet algorithm for the identification of P300 ERP component

abstract:
  Brain-computer interfaces have many algorithms based on the P300 component of
ERP. Modern industry has started to produce consumer grade EEG equipment which
is handy and not too expensive. This gives us an opportunity to use BCI in
everyday practice. In order to improve the performance of these devices, we
need effective algorithms for time series analysis and pattern recognition. We
have tested Emotiv Insight headset in a real live environment and we have
conducted several tests for series of standard wavelets in P300 pattern
recognition task.


title:
Approximate One-Dimensional Models for Monoenergetic Neutral Particle
  Transport in Ducts with Wall Migration

abstract:
  The problem of monoenergetic neutral particle transport in a duct, where
particles travel inside the duct walls, is treated using an approximate
one-dimensional model. The one-dimensional model uses three-basis functions, as
part of a previously derived weighted-residual procedure, to account for the
geometry of particle transport in a duct system (where particle migration into
the walls is not considered). Our model introduces two stochastic parameters to
account for particle-wall interactions: an albedo approximation yielding the
fraction of particles that return to the duct after striking the walls, and a
mean-distance travelled in the walls transverse to the duct by particles that
re-enter the duct. Our model produces a set of three transport equations with a
non-local scattering kernel. We solve these equations using discrete ordinates
with source iteration. Numerical results for the reflection and transmission
probabilities of neutron transport in ducts of circular cross section are
compared to Monte Carlo results computed using the MCNP code.


title: Full-Capacity Unitary Recurrent Neural Networks

abstract:
  Recurrent neural networks are powerful models for processing sequential data,
but they are generally plagued by vanishing and exploding gradient problems.
Unitary recurrent neural networks (uRNNs), which use unitary recurrence
matrices, have recently been proposed as a means to avoid these issues.
However, in previous experiments, the recurrence matrices were restricted to be
a product of parameterized unitary matrices, and an open question remains: when
does such a parameterization fail to represent all unitary matrices, and how
does this restricted representational capacity limit what can be learned? To
address this question, we propose full-capacity uRNNs that optimize their
recurrence matrix over all unitary matrices, leading to significantly improved
performance over uRNNs that use a restricted-capacity recurrence matrix. Our
contribution consists of two main components. First, we provide a theoretical
argument to determine if a unitary parameterization has restricted capacity.
Using this argument, we show that a recently proposed unitary parameterization
has restricted capacity for hidden state dimension greater than 7. Second, we
show how a complete, full-capacity unitary recurrence matrix can be optimized
over the differentiable manifold of unitary matrices. The resulting
multiplicative gradient step is very simple and does not require gradient
clipping or learning rate adaptation. We confirm the utility of our claims by
empirically evaluating our new full-capacity uRNNs on both synthetic and
natural data, achieving superior performance compared to both LSTMs and the
original restricted-capacity uRNNs.


title: The DESI Experiment Part I: Science,Targeting, and Survey Design

abstract:
  DESI (Dark Energy Spectroscopic Instrument) is a Stage IV ground-based dark
energy experiment that will study baryon acoustic oscillations (BAO) and the
growth of structure through redshift-space distortions with a wide-area galaxy
and quasar redshift survey. To trace the underlying dark matter distribution,
spectroscopic targets will be selected in four classes from imaging data. We
will measure luminous red galaxies up to $z=1.0$. To probe the Universe out to
even higher redshift, DESI will target bright [O II] emission line galaxies up
to $z=1.7$. Quasars will be targeted both as direct tracers of the underlying
dark matter distribution and, at higher redshifts ($ 2.1 < z < 3.5$), for the
Ly-$\alpha$ forest absorption features in their spectra, which will be used to
trace the distribution of neutral hydrogen. When moonlight prevents efficient
observations of the faint targets of the baseline survey, DESI will conduct a
magnitude-limited Bright Galaxy Survey comprising approximately 10 million
galaxies with a median $z\approx 0.2$. In total, more than 30 million galaxy
and quasar redshifts will be obtained to measure the BAO feature and determine
the matter power spectrum, including redshift space distortions.


title: The DESI Experiment Part II: Instrument Design

abstract:
  DESI (Dark Energy Spectropic Instrument) is a Stage IV ground-based dark
energy experiment that will study baryon acoustic oscillations and the growth
of structure through redshift-space distortions with a wide-area galaxy and
quasar redshift survey. The DESI instrument is a robotically-actuated,
fiber-fed spectrograph capable of taking up to 5,000 simultaneous spectra over
a wavelength range from 360 nm to 980 nm. The fibers feed ten three-arm
spectrographs with resolution $R= \lambda/\Delta\lambda$ between 2000 and 5500,
depending on wavelength. The DESI instrument will be used to conduct a
five-year survey designed to cover 14,000 deg$^2$. This powerful instrument
will be installed at prime focus on the 4-m Mayall telescope in Kitt Peak,
Arizona, along with a new optical corrector, which will provide a three-degree
diameter field of view. The DESI collaboration will also deliver a
spectroscopic pipeline and data management system to reduce and archive all
data for eventual public use.


title:
Percolation study for the capillary ascent of a liquid through a
  granular soil

abstract:
  Capillary rise plays a crucial role in the construction of road embankments
in flood zones, where hydrophobic compounds are added to the soil to suppress
the rising of water and avoid possible damage of the pavement. Water rises
through liquid bridges, menisci and trimers, whose width and connectivity
depends on the maximal half-length {\lambda} of the capillary bridges among
grains. Low {\lambda} generate a disconnect structure, with small clusters
everywhere. On the contrary, for high {\lambda}, create a percolating cluster
of trimers and enclosed volumes that form a natural path for capillary rise.
Hereby, we study the percolation transition of this geometric structure as a
function of {\lambda} on a granular media of monodisperse spheres in a random
close packing. We determine both the percolating threshold {\lambda}_{c} =
(0.049 \pm 0.004)R (with R the radius of the granular spheres), and the
critical exponent of the correlation length {\nu} = (0.830 \pm 0.051),
suggesting that the percolation transition falls into the universality class of
ordinary percolation.


title:
Searching for Binary Supermassive Black Holes via Variable Broad
  Emission Line Shifts: Low Binary Fraction

abstract:
  Supermassive black hole binaries (SMBHs) are expected to result from galaxy
mergers, and thus are natural byproducts (and probes) of hierarchical structure
formation in the Universe. They are also the primary expected source of
low-frequency gravitational wave emission. We search for binary BHs using
time-variable velocity shifts in broad Mg II emission lines of quasars with
multi-epoch observations. First, we inspect velocity shifts of the binary SMBH
candidates identified in Ju et al. (2013), using SDSS spectra with an
additional epoch of data that lengthens the typical baseline to ~10 yr. We find
variations in the line-of-sight velocity shifts over 10 years that are
comparable to the shifts observed over 1-2 years, ruling out the binary model
for the bulk of our candidates. We then analyze 1438 objects with 8 yr median
time baselines, from which we would expect to see velocity shifts >1000 km/s
from sub-pc binaries. We find only one object with an outlying velocity of 448
km/s, indicating, based on our modeling, that ~< 1 per cent (the value varies
with different assumptions) of SMBHs that are active as quasars reside in
binaries with ~0.1 pc separations. Binaries either sweep through these small
separations rapidly or stall at larger radii.


title:
Lasso, fractional norm and structured sparse estimation using a Hadamard
  product parametrization

abstract:
  Using a multiplicative reparametrization, I show that a subclass of $L_q$
penalties with $q\leq 1$ can be expressed as sums of $L_2$ penalties. It
follows that the lasso and other norm-penalized regression estimates may be
obtained using a very simple and intuitive alternating ridge regression
algorithm. As compared to a similarly intuitive EM algorithm for $L_q$
optimization, the proposed algorithm avoids some numerical instability issues
and is also competitive in terms of speed. Furthermore, the proposed algorithm
can be extended to accommodate sparse high-dimensional scenarios, generalized
linear models, and can be used to create structured sparsity via penalties
derived from covariance models for the parameters. Such model-based penalties
may be useful for sparse estimation of spatially or temporally structured
parameters.


title: String solutions in $AdS_3\times S^3\times S^3\times S^1$ with $B$-field

abstract:
  We consider strings living in $AdS_3\times S^3\times S^3\times S^1$ with
nonzero $B$-field. By using specific ansatz for the string embedding, we obtain
a class of solutions corresponding to strings moving in the whole ten
dimensional space-time. For the $AdS_3$ subspace, these solutions are given in
terms of incomplete elliptic integrals. For the two three-spheres, they are
expressed in terms of Lauricella hypergeometric functions of many variables.
The conserved charges, i.e. the string energy, spin and angular momenta, are
also found.


title:
AKARI near-infrared background fluctuations arise from normal galaxy
  populations

abstract:
  We show that measurements of the fluctuations in the near-infrared background
(NIRB) from the AKARI satellite can be explained by faint galaxy populations at
low redshifts. We demonstrate this using reconstructed images from deep galaxy
catalogs (HUGS/S-CANDELS) and two independent galaxy population models. In all
cases, we find that the NIRB fluctuations measured by AKARI are consistent with
faint galaxies and there is no need for a contribution from unknown
populations. We find no evidence for a steep Rayleigh-Jeans spectrum for the
underlying sources as previously reported. The apparent Rayleigh-Jeans spectrum
at large angular scales is likely a consequence of galaxies being removed
systematically to deeper levels in the longer wavelength channels.


title: The quest for extragalactic magnetic fields

abstract:
  We review the observational and theoretical constraints on extragalactic
magnetic fields across cosmic environment. In the next decade, the combination
of sophisticated numerical simulations and various observational probes might
succeed in constraining the still elusive origin of magnetic fields on the
largest scales in the Universe.


title:
Optimal Signaling for Secure Communications over Gaussian MIMO Wiretap
  Channels

abstract:
  Optimal signalling over the Gaussian MIMO wire-tap channel is studied under
the total transmit power constraint. A closed-form solution for an optimal
transmit covariance matrix is obtained when the channel is strictly degraded.
In combination with the rank-1 solution, this provides the complete
characterization of the optimal covariance for the case of two transmit
antennas. The cases of weak eavesdropper and high SNR are considered. It is
shown that the optimal covariance does not converge to a scaled identity in the
high-SNR regime. Necessary optimality conditions and a tight upper bound on the
rank of an optimal covariance matrix are established for the general case,
along with a lower bound to the secrecy capacity, which is tight in a number of
scenarios.


title: Nanoparticle-assisted STED nanoscopy with gold nanospheres

abstract:
  We demonstrate stimulated emission depletion (STED) microscopy with 20 nm
gold nanospheres coated by fluorescent silica. Compared with previous
demonstrations of STED with a hybrid plasmonic fluorescent label, the current
implementation offers a substantially smaller label and a better resolution
improvement of up to 2.5-fold beyond the diffraction limit of confocal
microscopy. This is achieved at approximately 2 times lower intensity than
conventional STED based on dyes alone, and in an aqueous environment,
demonstrating the relevance to bio-imaging. Finally, we also show, for the
first time in this context, a 3-fold reduction in the rate of photobleaching
compared to standard dye-based STED, thus, enabling brighter images.


title:
Kinetic analysis of spin current contribution to spectrum of
  electromagnetic waves in spin-1/2 plasma, Part II: Dispersion dependencies

abstract:
  The dielectric permeability tensor for spin polarized plasmas derived in
terms of the spin-1/2 quantum kinetic model in six-dimensional phase space in
Part I of this work is applied for study of spectra of high-frequency
transverse and transverse-longitudinal waves propagating perpendicular to the
external magnetic field. Cyclotron waves are studied at consideration of waves
with electric field directed parallel to the external magnetic field. It is
found that the separate spin evolution modifies the spectrum of cyclotron
waves. These modifications increase with the increase of the spin polarization
and the number of the cyclotron resonance. Spin dynamics with no account of the
anomalous magnetic moment gives a considerable modification of spectra either.
The account of anomalous magnetic moment leads to a fine structure of each
cyclotron resonance. So, each cyclotron resonance splits on three waves.
Details of this spectrum and its changes with the change of spin polarization
are studied for the first and second cyclotron waves. A cyclotron resonance
existing at $\omega\approx0.001\mid\Omega_{e}\mid$ due to the anomalous
magnetic moment is also described, where $\mid\Omega_{e}\mid$ is the cyclotron
frequency. The ordinary waves does not have any considerable modification. The
electrostatic and electromagnetic Berstein modes are studied during the
analysis of waves propagating perpendicular to the external magnetic field with
the electric field perturbation directed perpendicular to the external field. A
modification of the oscillatory structure caused by the equilibrium spin
polarization is found in both regimes. Similar modification is found for the
extraordinary wave spectrum.


title: A correlated Anderson insulator on the honeycomb lattice

abstract:
  We study the effect of disorder on the semimetal -- Mott insulator transition
in the half-filled repulsive Hubbard model on a honeycomb lattice, a system
that features vanishing density of states at the Fermi level. Using the
determinant quantum Monte Carlo method, we characterize various phases in terms
of the bulk-limit antiferromagnetic (AF) order parameter, compressibility, and
temperature-dependent DC conductivity. In the clean limit, our data are
consistent with previous results showing a single quantum critical point
separating the semi-metallic and AF Mott insulating phases. With the presence
of randomness, a non-magnetic disordered insulating phase emerges. Inside this
disordered insulator phase, there is a crossover from a gapless Anderson-like
insulator to a gapped Mott-like insulator.


title: Theta dependence in Holographic QCD

abstract:
  We study the effects of the CP-breaking topological $\theta$-term in the
large $N_c$ QCD model by Witten, Sakai and Sugimoto with $N_f$ degenerate light
flavors. We first compute the ground state energy density, the topological
susceptibility and the masses of the lowest lying mesons, finding agreement
with expectations from the QCD chiral effective action. Then, focusing on the
$N_f=2$ case, we consider the baryonic sector and determine, to leading order
in the small $\theta$ regime, the related holographic instantonic soliton
solutions. We find that while the baryon spectrum does not receive ${\cal
O}(\theta)$ corrections, this is not the case for observables like the
electromagnetic form factor of the nucleons. In particular, it exhibits a
dipole term, which turns out to be vector-meson dominated. The resulting
neutron electric dipole moment, which is exactly the opposite as that of the
proton, is of the same order of magnitude of previous estimates in the
literature. Finally, we compute the CP-violating pion-nucleon coupling constant
${\bar g}_{\pi N N}$, finding that it is zero to leading order in the large
$N_c$ limit.


title:
NNLL resummation for the associated production of a top pair and a Higgs
  boson at the LHC

abstract:
  We study the resummation of soft gluon emission corrections to the production
of a top-antitop pair in association with a Higgs boson at the Large Hadron
Collider. Starting from a soft-gluon resummation formula derived in previous
work, we develop a bespoke parton-level Monte Carlo program which can be used
to calculate the total cross section along with differential distributions. We
use this tool to study the phenomenological impact of the resummation to
next-to-next-to-leading logarithmic (NNLL) accuracy, finding that these
corrections increase the total cross section and the differential distributions
with respect to NLO calculations of the same observables.


title:
Exploiting Spatio-Temporal Structure with Recurrent Winner-Take-All
  Networks

abstract:
  We propose a convolutional recurrent neural network, with Winner-Take-All
dropout for high dimensional unsupervised feature learning in multi-dimensional
time series. We apply the proposedmethod for object recognition with temporal
context in videos and obtain better results than comparable methods in the
literature, including the Deep Predictive Coding Networks previously proposed
by Chalasani and Principe.Our contributions can be summarized as a scalable
reinterpretation of the Deep Predictive Coding Networks trained end-to-end with
backpropagation through time, an extension of the previously proposed
Winner-Take-All Autoencoders to sequences in time, and a new technique for
initializing and regularizing convolutional-recurrent neural networks.


title: CO in distantly active comets

abstract:
  Activity of most comets near the Sun is dominated by sublimation of frozen
water, the most abundant ice in comets. Some comets, however, are active well
beyond the water-ice sublimation limit of ~3 AU. Three bodies dominate the
observational record and modeling efforts for distantly active comets: the
long-period comet C/1995 O1 Hale-Bopp and the short-period comets (with Centaur
orbits) 29P/Schwassmann Wachmann 1 and 2060 Chiron. We summarize what is known
about these three objects emphasizing their gaseous comae. We calculate their
CN/CO and CO2/CO production rate ratios from the literature and discuss
implications. Using our own data we derive CO production rates for all three
objects, in order to examine a correlation between gas production and different
orbital histories and/or size. We find that orbital history does not appear to
play a significant role in explaining 29P's CO production rates. 29P
outproduces Hale-Bopp at the same heliocentric distance, even though it has
been subjected to much more solar heating. Previous modeling work on such
objects predicts that 29P should have been de-volatilized over a fresher comet
like Hale-Bopp. This may point to 29P having a different orbital history than
current models predict, with its current orbit acquired more recently. On the
other hand, Chiron's CO measurements are consistent with it being significantly
depleted over its original state, perhaps due to increased radiogenic heating
made possible by its much larger size or its higher processing due to orbital
history. Observed spectral line profiles are consistent with development and
sublimation of icy grains at about 5-6 AU for 29P and Hale-Bopp, and this is
probably a common feature in distantly active comets, and an important source
of volatiles for all comets within 5 AU. In contrast, the narrow CO line
profiles indicate a nuclear, and not extended, origin for CO beyond ~4 AU.


title: LAST but not Least: Online Spanners for Buy-at-Bulk

abstract:
  The online (uniform) buy-at-bulk network design problem asks us to design a
network, where the edge-costs exhibit economy-of-scale. Previous approaches to
this problem used tree- embeddings, giving us randomized algorithms. Moreover,
the optimal results with a logarithmic competitive ratio requires the metric on
which the network is being built to be known up-front; the competitive ratios
then depend on the size of this metric (which could be much larger than the
number of terminals that arrive).
  We consider the buy-at-bulk problem in the least restrictive model where the
metric is not known in advance, but revealed in parts along with the demand
points seeking connectivity arriving online. For the single sink buy-at-bulk
problem, we give a deterministic online algorithm with competitive ratio that
is logarithmic in k, the number of terminals that have arrived, matching the
lower bound known even for the online Steiner tree problem. In the oblivious
case when the buy-at-bulk function used to compute the edge-costs of the
network is not known in advance (but is the same across all edges), we give a
deterministic algorithm with competitive ratio polylogarithmic in k, the number
of terminals.
  At the heart of our algorithms are optimal constructions for online Light
Approximate Shortest-path Trees (LASTs) and spanners, and their variants. We
give constructions that have optimal trade-offs in terms of cost and stretch.
We also define and give constructions for a new notion of LASTs where the set
of roots (in addition to the points) expands over time. We expect these
techniques will find applications in other online network-design problems.


title:
Photon echo in exciton-plasmon nanomaterials: a time-dependent signature
  of strong coupling

abstract:
  We investigate the dynamics of photon echo exhibited by exciton-plasmon
systems under strong coupling conditions. Using a self-consistent model based
on coupled Maxwell-Bloch equations we investigate femtosecond time dynamics of
ensembles of interacting molecules optically coupled to surface plasmon
supporting materials. It is shown that observed photon echoes under two pulse
pump-probe sequence are highly dependent on various material parameters such as
molecular concentration and periodicity. Simulations of photon echoes in
exciton-plasmon materials reveal a unique signature of the strong
exciton-plasmon coupling, namely a double-peak structure in spectra of recorded
echo signals. This phenomenon is shown to be related to hybrid states (upper
and lower polaritons) in exciton-plasmon systems under strong coupling
conditions. It is also demonstrated that the double-peak echo is highly
sensitive to mild deviations of the coupling from resonant conditions making it
a great tool for ultrafast probes.


title:
ODE and Random Boolean networks in application to modelling of
  6-mercaptopurine metabolism

abstract:
  We consider two approaches to modelling of cell metabolism of
6-mercaptopurine, which is one of the important chemotherapy drugs used for
treating of acute lymphocytic leukemia: kinetic ordinary differential equations
and random Boolean networks, and analyse their interplay with respect to taking
into account ATP concentration as a key parameter of switching between
different pathways. It is shown that Boolean networks, which allow for avoiding
complexity of general kinetic modelling, preserve an opportunity to the
reproduction of the principal switching mechanism. To keep a detailed
quantitative measure of the control parameter, a combined Boolean-ODE method is
proposed.


title:
The Durability and Fragility of Knowledge Infrastructures: Lessons
  Learned from Astronomy

abstract:
  Infrastructures are not inherently durable or fragile, yet all are fragile
over the long term. Durability requires care and maintenance of individual
components and the links between them. Astronomy is an ideal domain in which to
study knowledge infrastructures, due to its long history, transparency, and
accumulation of observational data over a period of centuries. Research
reported here draws upon a long-term study of scientific data practices to ask
questions about the durability and fragility of infrastructures for data in
astronomy. Methods include interviews, ethnography, and document analysis. As
astronomy has become a digital science, the community has invested in shared
instruments, data standards, digital archives, metadata and discovery services,
and other relatively durable infrastructure components. Several features of
data practices in astronomy contribute to the fragility of that infrastructure.
These include different archiving practices between ground- and space-based
missions, between sky surveys and investigator-led projects, and between
observational and simulated data. Infrastructure components are tightly
coupled, based on international agreements. However, the durability of these
infrastructures relies on much invisible work - cataloging, metadata, and other
labor conducted by information professionals. Continual investments in care and
maintenance of the human and technical components of these infrastructures are
necessary for sustainability.


title: Spontaneous excitation of an atom in a Kerr spacetime

abstract:
  We consider radiative processes of an atom in a rotating black-hole
background. We assume the atom, represented by a hypothetical two-level system,
is coupled via a monopole interaction with a massless quantum scalar field
prepared in each one of the usual physical vacuum states of interest. We
constrain ourselves to two different states of motion for the atom, namely a
static situation in which the atom is placed at a fixed radial distance, and
also the case in which it has a stationary motion but with zero angular
momentum. We study the structure of the rate of variation of the atomic energy.
The intention is to clarify in a quantitative way the effect of the
distinguished contributions of vacuum fluctuations and radiation reaction on
spontaneous excitation and on spontaneous emission of atoms. In particular, we
are interested in the comprehension of the combined action of the different
physical processes underlying the Hawking effect in the scenario of rotating
black holes as well as the Unruh-Starobinskii effect. We demonstrate that, in
the case of static atoms, spontaneous excitation is also connected with the
Unruh-Starobinskii effect, but only in the case of the quantum field prepared
in the Frolov-Thorne vacuum state. In addition, we show that, in the ZAMOs
perspective, the Boulware vacuum state contains an outward flux of particles as
a consequence of the black-hole superradiance. The possible relevance of the
findings in the present work is discussed.


title: Holomorphy of adjoint $L$ functions for quasisplit A2

abstract:
  We study the poles of the twisted adjoint L function of a generic cuspidal
automorphic representation of GL(3) or a quasisplit unitary group using a
method pioneered by Ginzburg and Jiang and based on the theory of integral
representations.


title:
Kernel Bandwidth Selection for SVDD: Peak Criterion Approach for Large
  Data

abstract:
  Support Vector Data Description (SVDD) provides a useful approach to
construct a description of multivariate data for single-class classification
and outlier detection with various practical applications. Gaussian kernel used
in SVDD formulation allows flexible data description defined by observations
designated as support vectors. The data boundary of such description is
non-spherical and conforms to the geometric features of the data. By varying
the Gaussian kernel bandwidth parameter, the SVDD-generated boundary can be
made either smoother (more spherical) or tighter/jagged. The former case may
lead to under-fitting, whereas the latter may result in overfitting. Peak
criterion has been proposed to select an optimal value of the kernel bandwidth
to strike the balance between the data boundary smoothness and its ability to
capture the general geometric shape of the data. Peak criterion involves
training SVDD at various values of the kernel bandwidth parameter. When
training datasets are large, the time required to obtain the optimal value of
the Gaussian kernel bandwidth parameter according to Peak method can become
prohibitively large. This paper proposes an extension of Peak method for the
case of large data. The proposed method gives good results when applied to
several datasets. Two existing alternative methods of computing the Gaussian
kernel bandwidth parameter (Coefficient of Variation and Distance to the
Farthest Neighbor) were modified to allow comparison with the proposed method
on convergence. Empirical comparison demonstrates the advantage of the proposed
method.


title: Signature of Hanle Precession in Trilayer MoS2: Theory and Experiment

abstract:
  Valley-spin coupling in transition-metal dichalcogenides (TMDs) can result in
unusual spin transport behaviors under an external magnetic field. Nonlocal
resistance measured from 2D materials such as TMDs via electrical Hanle
experiments are predicted to exhibit nontrivial features, compared with results
from conventional materials due to the presence of intervalley scattering as
well as a strong internal spin-orbit field. Here, for the first time, we report
the all-electrical injection and non-local detection of spin polarized carriers
in trilayer MoS_2 films. We calculate the Hanle curves theoretically when the
separation between spin injector and detector is much larger than spin
diffusion length, \lamda_s. The experimentally observed curve matches the
theoretically-predicted Hanle shape under the regime of slow intervalley
scattering. The estimated spin life-time was found to be around 110 ps at 30 K.


title:
Understanding emergent collectivity and clustering in nuclei from a
  symmetry-based no-core shell-model perspective

abstract:
  We present a detailed discussion of the structure of the low-lying
positive-parity energy spectrum of $^{12}$C from a no-core shell-model
perspective. The approach utilizes a fraction of the usual shell-model space
and extends its multi-shell reach via the symmetry-based no-core symplectic
shell model (NCSpM) with a simple, physically-informed effective interaction.
We focus on the ground-state rotational band, the Hoyle state and its $2^+$ and
$4^+$ excitations, as well as the giant monopole $0^+$ resonance, which is a
vibrational breathing mode of the ground state. This, in turn, allows us to
address the open question about the structure of the Hoyle state and its
rotational band. In particular, we find that the Hoyle state is best described
through deformed prolate collective modes rather than vibrational modes, while
we show that the higher-lying giant monopole $0^+$ resonance resembles the
oblate deformation of the $^{12}$C ground state. In addition, we identify the
giant monopole $0^+$ and quadrupole $2^+$ resonances of selected light and
intermediate-mass nuclei, along with other observables of $^{12}$C, including
matter rms radii, electric quadrupole moments, as well as $E2$ and $E0$
transition rates.


title:
The Panchromatic Hubble Andromeda Treasury XVII. Examining Obscured Star
  Formation with Synthetic Ultraviolet Flux Maps in M31

abstract:
  We present synthetic far- and near-ultraviolet (FUV and NUV) maps of M31,
both with and without dust reddening. These maps were constructed from
spatially-resolved star formation histories (SFHs) derived from optical Hubble
Space Telescope imaging of resolved stars, taken as part of the Panchromatic
Hubble Andromeda Treasury program. We use stellar population synthesis modeling
to generate synthetic UV maps with projected spatial resolution of $\sim$100 pc
($\sim$24 arcseconds) The predicted UV flux agrees well with the observed flux,
with median ratios between the modeled and observed flux of
$\log_{10}(f^{syn}/f^{obs}) = 0.03\pm0.24$ and $-0.03\pm0.16$ in the FUV and
NUV, respectively. This agreement is particularly impressive given that we used
only optical photometry to construct these UV maps. We use the dust-free maps
to examine properties of obscured flux and star formation by comparing our
reddened and dust-free FUV flux maps with the observed FUV and FUV+24{\mu}m
flux to examine the fraction of obscured flux. The synthetic flux maps require
that $\sim$90% of the FUV flux in M31 is obscured by dust, while the
GALEX-based methods suggest that $\sim$70% of the flux is obscured. This
increase in the obscured flux estimate is driven by significant differences
between the dust-free synthetic FUV flux and that derived when correcting the
observed FUV for dust with 24{\mu}m observations. The difference is further
illustrated when we compare the SFRs derived from the FUV+24{\mu}m flux with
the 100 Myr average SFR from the SFHs. The 24{\mu}m-corrected FUV flux
underestimates the SFR by a factor of $\sim$2.3 - 2.5. [abridged]


title: Energy Cascade in Quantum Gases

abstract:
  Energy cascade is ubiquitous in systems far from equilibrium. Facilitated by
particle interactions and external forces, it can lead to highly complex
phenomena like fully developed turbulence, characterized by power law velocity
correlation functions. Yet despite decades of research, how these power laws
emerge from first principle remains unclear. Recently, experiments show that
when a Bose condensate is subjected to periodic shaking, its momentum
distribution exhibits a power law behavior. The flexibility of cold atom
experiments has provided new opportunities to explore the emergence of these
power laws, and to disentangle different sources of energy cascade. Here, we
point out that recent experiments in cold atoms imply that classical turbulence
is part of a larger family of scale invariant phenomena that include ideal
gases. Moreover, the property of the entire family is contained in the
structure of its Floquet states. For ideal gases, we show analytically that its
momentum distribution acquires a $1/q^2$ tail in each dimension when it is
shaken periodically.


title: Tailoring steep density profile with unstable points

abstract:
  The mesoscopic properties of a plasma in a cylindrical magnetic field are
investigated from the view point of test-particle dynamics. When the system has
enough time and spatial symmetries, a Hamiltonian of a test particle is
completely integrable and can be reduced to a single degree of freedom
Hamiltonian for each initial state. The reduced Hamiltonian sometimes has
unstable fixed points (saddle points) and associated separatrices. To choose
among available dynamically compatible equilibrium states of the one particle
density function of these systems we use a maximum entropy principle and
discuss how the unstable fixed points affect the density profile or a local
pressure gradient, and are able to create a steep profile that improves plasma
confinement.


title:
Swift Ultraviolet Survey of the Magellanic Clouds (SUMaC). I. Shape of
  the Ultraviolet Dust Extinction Law and Recent Star Formation History of the
  Small Magellanic Cloud

abstract:
  We present the first results from the Swift Ultraviolet Survey of the
Magellanic Clouds (SUMaC), the highest resolution ultraviolet (UV) survey of
the Magellanic Clouds yet completed. In this paper, we focus on the Small
Magellanic Cloud (SMC). When combined with multi-wavelength optical and
infrared observations, the three near-UV filters on the Swift
Ultraviolet/Optical Telescope are conducive to measuring the shape of the dust
extinction curve and the strength of the 2175\AA\ dust bump. We divide the SMC
into UV-detected star-forming regions and large 200" (58~pc) pixels and then
model the spectral energy distributions using a Markov Chain Monte Carlo method
to constrain the ages, masses, and dust curve properties. We find that the
majority of the SMC has a 2175\AA\ dust bump, which is larger to the northeast
and smaller to the southwest, and that the extinction curve is universally
steeper than the Galactic curve. We also derive a star formation history and
find evidence for peaks in the star formation rate at 6-10 Myr, 30-80 Myr, and
400 Myr, the latter two of which are consistent with previous work.