title:
Probing WHIM around Galaxy Clusters with Fast Radio Bursts and the
  Sunyaev-Zel'dovich effect

abstract:
  We propose a new method to probe the Warm Hot Intergalactic Medium (WHIM)
beyond the virial radius (R_200) of a cluster of galaxies, where X-ray
observations are not easily achievable. In this method, we use dispersion
measures (DMs) of Fast Radio Bursts (FRBs) that appear behind the cluster and
the Sunyaev-Zel'dovich (SZ) effect towards the cluster. The DMs reflect the
density of the intracluster medium (ICM) including the WHIM. If we observe a
sufficient number of FRBs in the direction of the cluster, we can derive the
density profile from the DMs. Similarly, we can derive the pressure profile
from the SZ effect. By combining the density and the pressure profiles, the
temperature profile can be obtained. Based on mock observations of nearby
clusters, we find that the density of the WHIM can be determined even at > 2
R_200 from the cluster center when FRB observations with the Square Kilometre
Array (SKA) become available. The temperature can be derived out to r~ 1.5
R_200, and the radius is limited by the current sensitivity of SZ observations.


title:
The High Cadence Transient Survey (HiTS) - I. Survey design and
  supernova shock breakout constraints

abstract:
  We present the first results of the High cadence Transient Survey (HiTS), a
survey whose objective is to detect and follow up optical transients with
characteristic timescales from hours to days, especially the earliest hours of
supernova (SN) explosions. HiTS uses the Dark Energy Camera (DECam) and a
custom made pipeline for image subtraction, candidate filtering and candidate
visualization, which runs in real-time to be able to react rapidly to the new
transients. We discuss the survey design, the technical challenges associated
with the real-time analysis of these large volumes of data and our first
results. In our 2013, 2014 and 2015 campaigns we have detected more than 120
young SN candidates, but we did not find a clear signature from the short-lived
SN shock breakouts (SBOs) originating after the core collapse of red supergiant
stars, which was the initial science aim of this survey. Using the empirical
distribution of limiting-magnitudes from our observational campaigns we
measured the expected recovery fraction of randomly injected SN light curves
which included SBO optical peaks produced with models from Tominaga et al.
(2011) and Nakar & Sari (2010). From this analysis we cannot rule out the
models from Tominaga et al. (2011) under any reasonable distributions of
progenitor masses, but we can marginally rule out the brighter and longer-lived
SBO models from Nakar & Sari (2010) under our best-guess distribution of
progenitor masses. Finally, we highlight the implications of this work for
future massive datasets produced by astronomical observatories such as LSST.


title:
Photo-$z$ with CuBAN$z$: An improved photometric redshift estimator
  using Clustering aided Back Propagation Neural network

abstract:
  We present an improved photometric redshift estimator code, CuBAN$z$, that is
publicly available at https://goo.gl/fpk90V}{https://goo.gl/fpk90V. It uses the
back propagation neural network along with clustering of the training set,
which makes it more efficient than existing neural network codes. In CuBAN$z$,
the training set is divided into several self learning clusters with galaxies
having similar photometric properties and spectroscopic redshifts within a
given span. The clustering algorithm uses the color information (i.e. $u-g$,
$g-r$ etc.) rather than the apparent magnitudes at various photometric bands as
the photometric redshift is more sensitive to the flux differences between
different bands rather than the actual values. Separate neural networks are
trained for each cluster using all possible colors, magnitudes and
uncertainties in the measurements. For a galaxy with unknown redshift, we
identify the closest possible clusters having similar photometric properties
and use those clusters to get the photometric redshifts using the particular
networks that were trained using those cluster members. For galaxies that do
not match with any training cluster, the photometric redshifts are obtained
from a separate network that uses entire training set. This clustering method
enables us to determine the redshifts more accurately. SDSS Stripe 82 catalog
has been used here for the demonstration of the code. For the clustered sources
with redshift range $z_{\rm spec}<0.7$, the residual error ($\langle (z_{{\rm
spec}}-z_{{\rm phot}})^2\rangle^{1/2} $) in the training/testing phase is as
low as 0.03 compared to the existing ANNz code that provides residual error on
the same test data set of 0.05. Further, we provide a much better estimate of
the uncertainty of the derived photometric redshift.


title:
Partially Acoustic Dark Matter, Interacting Dark Radiation, and Large
  Scale Structure

abstract:
  The standard paradigm of collisionless cold dark matter is in tension with
measurements on large scales. In particular, the best fit values of the Hubble
rate $H_0$ and the matter density perturbation $\sigma_8$ inferred from the
cosmic microwave background seem inconsistent with the results from direct
measurements. We show that both problems can be solved in a framework in which
dark matter consists of two distinct components, a dominant component and a
subdominant component. The primary component is cold and collisionless. The
secondary component is also cold, but interacts strongly with dark radiation,
which itself forms a tightly coupled fluid. The growth of density perturbations
in the subdominant component is inhibited by dark acoustic oscillations due to
its coupling to the dark radiation, solving the $\sigma_8$ problem, while the
presence of tightly coupled dark radiation ameliorates the $H_0$ problem. The
subdominant component of dark matter and dark radiation continue to remain in
thermal equilibrium until late times, inhibiting the formation of a dark disk.
We present an example of a simple model that naturally realizes this scenario
in which both constituents of dark matter are thermal WIMPs. Our scenario can
be tested by future stage-IV experiments designed to probe the CMB and large
scale structure.


title: Corrections to $n_s$ and $n_t$ from high scale physics

abstract:
  When modelling inflaton fluctuations as a free quantum scalar field, the
initial vacuum is conventionally imposed at the infinite past. This is called
the Bunch-Davies (BD) vacuum. If however an asymptotically Minkowskian past
does not exist, this requires modifications. We derive corrections to the
scalar spectral index $n_s$ and the tensor tilt $n_t$ descending from arbitrary
mixed states or from explicit non-BD initial conditions. The former may stem
from some pre-inflationary background and can redshift away whereas the latter
are induced by a timelike hypersurface parametrising a physical cut-off. In
both cases, we find that corrections scale in parts or fully as $\mathcal
O(\epsilon)$ where $\epsilon$ is the first slow-roll parameter. The precise
observational footprint is hence dependent on the model driving inflation.
Further, we show how the inflationary consistency relation is altered. We thus
provide an analytic handle on possible high scale or pre-inflationary physics.


title:
The growth of typical star-forming galaxies and their super massive
  black holes across cosmic time since z~2

abstract:
  Understanding galaxy formation and evolution requires studying the interplay
between the growth of galaxies and the growth of their black holes across
cosmic time. Here we explore a sample of Ha-selected star-forming galaxies from
the HiZELS survey and use the wealth of multi-wavelength data in the COSMOS
field (X-rays, far-infrared and radio) to study the relative growth rates
between typical galaxies and their central supermassive black holes, from
z=2.23 to z=0. Typical star-forming galaxies at z~1-2 have black hole accretion
rates (BHARs) of 0.001-0.01 Msun/yr and star formation rates (SFRs) of ~10-40
Msun/yr, and thus grow their stellar mass much quicker than their black hole
mass (~3.3 orders of magnitude faster). However, ~3% of the sample (the sources
detected directly in the X-rays) show a significantly quicker growth of the
black hole mass (up to 1.5 orders of magnitude quicker growth than the typical
sources). BHARs fall from z=2.23 to z=0, with the decline resembling that of
star formation rate density or the typical SFR. We find that the average black
hole to galaxy growth (BHAR/SFR) is approximately constant for star-forming
galaxies in the last 11 Gyrs. The relatively constant BHAR/SFR suggests that
these two quantities evolve equivalently through cosmic time and with
practically no delay between the two.


title: The evolution of star formation histories of quiescent galaxies

abstract:
  Although there has been much progress in understanding how galaxies evolve,
we still do not understand how and when they stop forming stars and become
quiescent. We address this by applying our galaxy spectral energy distribution
models, which incorporate physically motivated star formation histories (SFHs)
from cosmological simulations, to a sample of quiescent galaxies at
$0.2<z<2.1$. A total of 845 quiescent galaxies with multi-band photometry
spanning rest-frame ultraviolet through near-infrared wavelengths are selected
from the CANDELS dataset. We compute median SFHs of these galaxies in bins of
stellar mass and redshift. At all redshifts and stellar masses, the median SFHs
rise, reach a peak, and then decline to reach quiescence. At high redshift, we
find that the rise and decline are fast, as expected because the Universe is
young. At low redshift, the duration of these phases depends strongly on
stellar mass. Low-mass galaxies ($\log(M_{\ast}/M_{\odot})\sim9.5$) grow on
average slowly, take a long time to reach their peak of star formation
($\gtrsim 4$ Gyr), and the declining phase is fast ($\lesssim 2$ Gyr).
Conversely, high-mass galaxies ($\log(M_{\ast}/M_{\odot})\sim11$) grow on
average fast ($\lesssim 2$ Gyr), and, after reaching their peak, decrease the
star formation slowly ($\gtrsim 3$ Gyr). These findings are consistent with
galaxy stellar mass being a driving factor in determining how evolved galaxies
are, with high-mass galaxies being the most evolved at any time (i.e.,
downsizing). The different durations we observe in the declining phases also
suggest that low- and high-mass galaxies experience different quenching
mechanisms that operate on different timescales.


title: The Sorkin-Johnston State in a Patch of the Trousers Spacetime

abstract:
  A quantum scalar field in a patch of a fixed, topology-changing, $1+1$
dimensional "trousers" spacetime is studied using the Sorkin-Johnston
formalism. The isometry group of the patch is the dihedral group, the symmetry
group of the square. The theory is shown to be pathological in a way that can
be interpreted as the topology change giving rise to a divergent energy, in
agreement with previous results. In contrast to previous results, it is shown
that the infinite energy is localised not only on the future light cone of the
topology changing singularity, but also on the past cone, due to the time
reversal symmetry of the Sorkin-Johnston state.


title:
Dispersive treatment of $K_S\to\gamma\gamma$ and
  $K_S\to\gamma\ell^+\ell^-$

abstract:
  We analyse the rare kaon decays $K_S \to \gamma\gamma$ and $K_S \to
\gamma\ell^+\ell^-$ $(\ell = e \mbox{ or } \mu)$ in a dispersive framework in
which the weak Hamiltonian carries momentum. Our analysis extends predictions
from lowest order $SU(3)_L\times SU(3)_R$ chiral perturbation theory
($\chi$PT$_3$) to fully account for effects from final-state interactions, and
is free from ambiguities associated with extrapolating the kaon off-shell.
Given input from $K_S \to \pi\pi$ and $\gamma\gamma^{(*)}\to\pi\pi$, we solve
the once-subtracted dispersion relations numerically to predict the rates for
$K_S \to \gamma\gamma$ and $K_S \to \gamma\ell^+\ell^-$. In the leptonic modes,
we find sizeable corrections to the $\chi$PT$_3$ predictions for the integrated
rates.


title:
The Milky Way's halo in 6D: Gaia's Radial Velocity Spectrometer
  performance

abstract:
  Gaia's Radial Velocity Spectrometer (RVS) has been operating in routine phase
for over one year since initial commissioning. RVS continues to work well but
the higher than expected levels of straylight reduce the limiting magnitude.
The end-of-mission radial-velocity (RV) performance requirement for G2V stars
was 15 km/s at V = 16.5 mag. Instead, 15 km/s precision is achieved at 15 < V <
16 mag, consistent with simulations that predict a loss of 1.4 mag. Simulations
also suggest that changes to Gaia's onboard software could recover ~0.14 mag of
this loss. Consequently Gaia's onboard software was upgraded in April 2015. The
status of this new commissioning period is presented, as well as the latest
scientific performance of the on-ground processing of RVS spectra. We
illustrate the implications of the RVS limiting magnitude on Gaia's view of the
Milky Way's halo in 6D using the Gaia Universe Model Snapshot (GUMS).


title:
Performance study of Lagrangian methods: reconstruction of large scale
  peculiar velocities and baryonic acoustic oscillations

abstract:
  NoAM for "No Action Method" is a framework for reconstructing the past orbits
of observed tracers of the large scale mass density field. It seeks exact
solutions of the equations of motion (EoM), satisfying initial homogeneity and
the final observed particle (tracer) positions. The solutions are found
iteratively reaching a specified tolerance defined as the RMS of the distance
between reconstructed and observed positions. Starting from a guess for the
initial conditions, NoAM advances particles using standard N-body techniques
for solving the EoM. Alternatively, the EoM can be replaced by any
approximation such as Zel'dovich and second order perturbation theory (2LPT).
NoAM is suitable for billions of particles and can easily handle non-regular
volumes, redshift space, and other constraints. We implement NoAM to
systematically compare Zel'dovich, 2LPT, and N-body dynamics over diverse
configurations ranging from idealized high-res periodic simulation box to
realistic galaxy mocks. Our findings are (i) Non-linear reconstructions with
Zel'dovich, 2LPT, and full dynamics perform better than linear theory only for
idealized catalogs in real space. For realistic catalogs, linear theory is the
optimal choice for reconstructing velocity fields smoothed on scales > 5 Mpc/h.
(ii) all non-linear back-in-time reconstructions tested here, produce
comparable enhancement of the baryonic oscillation signal in the correlation
function.


title: Unbiased pseudo-Cl power spectrum estimation with mode projection

abstract:
  With the steadily improving sensitivity afforded by current and future galaxy
surveys, a robust extraction of two-point correlation function measurements may
become increasingly hampered by the presence of astrophysical foregrounds or
observational systematics. The concept of mode projection has been introduced
as a means to remove contaminants for which it is possible to construct a
spatial map reflecting the expected signal contribution. Owing to its
computational efficiency compared to minimum-variance methods, the sub-optimal
pseudo-Cl (PCL) power spectrum estimator is a popular tool for the analysis of
high-resolution data sets. Here, we integrate mode projection into the
framework of PCL power spectrum estimation. In contrast to results obtained
with optimal estimators, we show that the uncorrected projection of template
maps leads to biased power spectra. Based on analytical calculations, we find
exact closed-form expressions for the expectation value of the bias and
demonstrate that they can be recast in a form that allows a numerically
efficient evaluation, preserving the favorable O(l_max^3) time complexity of
PCL estimator algorithms. Using simulated data sets, we assess the scaling of
the bias with various analysis parameters and demonstrate that it can be
reliably removed. We conclude that in combination with mode projection, PCL
estimators allow for a fast and robust computation of power spectra in the
presence of systematic effects -- properties in high demand for the analysis of
ongoing and future large scale structure surveys.


title:
Geometric Phase of a Spin-1/2 Particle Coupled to a Quantum Vector
  Operator

abstract:
  We calculate Berry's phase when the driving field, to which a spin-1/2 is
coupled adiabatically, rather than the familiar classical magnetic field, is a
quantum vector operator, of noncommuting, in general, components, e.g., the
angular momentum of another particle, or another spin. The geometric phase of
the entire system, spin plus "quantum driving field", is first computed, and is
then subdivided into the two subsystems, using the Schmidt decomposition of the
total wave function -the resulting expression shows a marked, purely quantum
effect, involving the commutator of the field components. We also compute the
corresponding mean "classical" phase, involving a precessing magnetic field in
the presence of noise, up to terms quadratic in the noise amplitude -the
results are shown to be in excellent agreement with numerical simulations in
the literature. Subtleties in the relation between the quantum and classical
case are pointed out, while three concrete examples illustrate the scope and
internal consistency of our treatment.


title: Dynamical disentangling and cooling of atoms in bilayer optical lattices

abstract:
  We show how experimentally available bilayer lattice systems can be used to
prepare quantum many-body states with exceptionally low entropy in one layer,
by dynamically disentangling the two layers. This disentangling operation moves
one layer - subsystem $A$ - into a regime where excitations in $A$ develop a
single-particle gap. As a result, this operation maps directly to cooling for
subsystem $A$, with entropy being shuttled to the other layer. For both bosonic
and fermionic atoms, we study the dynamics of this process, and show that
disentangling can be realised cleanly in ongoing optical lattice experiments.
The corresponding entanglement entropies are directly measurable with quantum
gas microscopes, and as a tool for producing lower-entropy states, this
technique opens a range of applications beginning with simplifying production
of anti-ferromagnetically ordered states of fermions.


title:
The Way To a Double Degenerate: $\sim15-20$ per cent of $1M_{\odot} \le
  M \le 8M_{\odot}$ Stars have a $M>1M_{\odot}$ Companion

abstract:
  We find that $\sim 15-20$ per cent of A-type stars or red giants are bound
with a massive companion ($M_{\rm secondary} > 1M_{\odot}$) in an intermediate
wide orbit ($0.5<P<5000\mbox{ yr}$). These massive binaries are expected to
form wide-orbit, double-degenerate systems (WODDs) within $\lesssim10\mbox{
Gyr}$ implying that $\sim10$ per cent of white dwarfs (WDs) are expected to be
part of a WODD with a lighter WD companion. These findings are based on an
analysis of previous adaptive optics observations of A-type stars and radial
velocity measurements of red giants and shed light on the claimed discrepancy
between the seemingly high multiplicity function of stars and the rather low
number of detected double degenerates. We expect that GAIA will find $\sim 10$
new WODDs within $20\mbox{ pc}$ from the sun. These results put a stringent
constraint on the collision model of type Ia supernovae in which triple stellar
systems that include a WODD as the inner binary are required to be abundant.


title:
Uniform Contribution of Supernova Explosions to the Chemical Enrichment
  of Abell 3112 out to R200

abstract:
  The spatial distribution of the metals residing in the intra-cluster medium
(ICM) of galaxy clusters records all the information on a cluster's
nucleosynthesis and chemical enrichment history. We present measurements from a
total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core
galaxy cluster Abell 3112 out its virial radius (~ 1470 kpc). We find that the
ratio of the observed supernova type Ia explosions to the total supernova
explosions has a uniform distribution at a level of 12-16% out to the cluster's
virial radius. The observed fraction of type Ia supernova explosions is in
agreement with the corresponding fraction found in our Galaxy and the chemical
enrichment of our Galaxy. The non-varying supernova enrichment suggests that
the ICM in cluster outskirts was enriched by metals at an early stage before
the cluster itself was formed during the period of intense star formation
activity. Additionally, we find that the 2D delayed detonation model CDDT
produces significantly worse fits to the X-ray spectra compared to simple 1D W7
models. This is due to the relative overestimate of Si, and underestimate of
Mg, in these models with respect to the measured abundances.


title: Holography of the Dirac Fluid in Graphene with two currents

abstract:
  Recent experiments have uncovered evidence of the strongly coupled nature of
the graphene: the Wiedemann-Franz law is violated by up to a factor of 20 near
the charge neutral point. We describe this strongly-coupled plasma by a
holographic model in which there are two distinct conserved U(1) currents. We
find that our analytic results for the transport coefficients for two current
model have a significantly improved match to the density dependence of the
experimental data than the models with only one current. The additive structure
in the transports coefficients plays an important role. We also suggest the
origin of the two currents.


title:
UV Absorption Line Ratios in Circumgalactic Medium at Low Redshift in
  Realistic Cosmological Hydrodynamic Simulations

abstract:
  Utilizing high-resolution cosmological hydrodynamic simulations we
investigate various ultra-violet absorption lines in the circumgalactic medium
of star forming galaxies at low redshift, in hopes of checking and alleviating
the claimed observational conundrum of the ratio of NV to OVI absorbers, among
others. We find a satisfactory agreement between simulations and extant
observational data with respect to the ratios of the following four line pairs
examined, NV/OVI, SiIV/OVI, NIII/OVI and NII/OVI. For the pairs involving
nitrogen lines, we examine two cases of nitrogen abundance, one with constant
N/O ratio and the other with varying N/O ratio, with the latter motivated by
theoretical considerations of two different synthetic sources of nitrogen that
is empirically verified independently. Along a separate vector, for all line
pairs, we examine two cases of radiation field, one with the Haardt-Madau
background radiation field and the other with an additional local radiation
field sourced by hot gas in the host galaxy. In all cases, two-sample
Kolmogorov-Smirnov tests indicate excellent agreements. We find that the
apparent agreements between simulations and observations will be strongly
tested, if the bulk of current upper limits of various line ratios are turned
into actual detections. We show that an increase in observational sensitivity
by 0.2 dex will already start to significantly constrain the models.


title: Global simulations of Minkowski space-time including space-like infinity

abstract:
  In this work, we study linearised gravitational fields on the entire
Minkowski space-time including space-like infinity. The generalised conformal
field equations linearised about a Minkowski background are utilised for this
purpose. In principle, this conformal representation of Einstein's equations
can be used to carry out global simulations of Minkowski space-time. We
investigate thoroughly this possibility.


title: Chromatic homology, Khovanov homology, and torsion

abstract:
  In the first few homological gradings, there is an isomorphism between the
Khovanov homology of a link and the categorification of the chromatic
polynomial of a graph related to the link. In this article, we show that the
categorification of the chromatic polynomial only contains torsion of order
two, and hence Khovanov homology only contains torsion of order two in the
gradings where the isomorphism is defined. We also prove that odd Khovanov
homology is torsion-free in its first few homological gradings.


title:
Long-term, Multiwavelength Light Curves of Ultra-cool Dwarfs: I. An
  Interplay of Starspots & Clouds Likely Drive the Variability of the L3.5
  dwarf 2MASS 0036+18

abstract:
  We present multi-telescope, ground-based, multiwavelength optical and
near-infrared photometry of the variable L3.5 ultra-cool dwarf 2MASSW
J0036159+182110. We present 22 nights of photometry of 2MASSW J0036159+182110,
including 7 nights of simultaneous, multiwavelength photometry, spread over
~120 days allowing us to determine the rotation period of this ultra-cool dwarf
to be 3.080 +/- 0.001 hr. Our many nights of multiwavelength photometry allow
us to observe the evolution, or more specifically the lack thereof, of the
light curve over a great many rotation periods. The lack of discernible phase
shifts in our multiwavelength photometry, and that the amplitude of variability
generally decreases as one moves to longer wavelengths for 2MASSW
J0036159+182110, is generally consistent with starspots driving the variability
on this ultra-cool dwarf, with starspots that are ~100 degrees K hotter or
cooler than the ~1700 K photosphere. Also, reasonably thick clouds are required
to fit the spectra of 2MASSW J0036159+182110, suggesting there likely exists
some complex interplay between the starspots driving the variability of this
ultra-cool dwarf and the clouds that appear to envelope this ultra-cool dwarf.


title:
Long-term, Multiwavelength Light Curves of Ultra-Cool Dwarfs: II. The
  evolving Light Curves of the T2.5 SIMP 0136 & the Uncorrelated Light Curves
  of the M9 TVLM 513

abstract:
  We present 17 nights of ground-based, near-infrared photometry of the
variable L/T transition brown dwarf SIMP J013656.5+093347 and an additional 3
nights of ground-based photometry of the radio-active late M-dwarf TVLM
513-46546. Our TVLM 513-46546 photometry includes 2 nights of simultaneous,
multiwavelength, ground-based photometry, in which we detect obvious J-band
variability, but do not detect I-band variability of similar amplitude,
confirming that the variability of TVLM 513-46546 most likely arises from
clouds or aurorae, rather than starspots. Our photometry of SIMP
J013656.5+093347 includes 15 nights of J-band photometry that allow us to
observe how the variable light curve of this L/T transition brown dwarf evolves
from rotation period to rotation period, night-to-night and week-to-week. We
estimate the rotation period of SIMP J013656.5+093347 as 2.406 +/- 0.008 hours,
and do not find evidence for obvious differential rotation. The peak-to-peak
amplitude displayed by SIMP J013656.5+093347 in our light curves evolves from
greater than 6% to less than 1% in a matter of days, and the typical timescale
for significant evolution of the SIMP J013656.5+093347 light curve appears to
be approximately <1 to 10 rotation periods. This suggests that those performing
spectrophotometric observations of brown dwarfs should be cautious in their
interpretations comparing the spectra between a variable brown dwarf's maximum
flux and minimum flux from observations lasting only approximately a rotation
period, as these comparisons may depict the spectral characteristics of a
single, ephemeral snapshot, rather than the full range of characteristics.


title: Reciprocity of Dedekind sums and the Euler class

abstract:
  Dedekind sums are arithmetic sums that were first introduced by Dedekind in
the context of elliptic functions and modular forms, and later recognized to be
surprisingly ubiquitous. Among the variations and generalizations introduced
since, there is a construction of Dedekind sums for lattices in
$\mathrm{SL}_2(\mathbf{R}). Building upon work of Asai, we prove the
reciprocity law for these Dedekind sums, based on a concrete realization of the
Euler class. As an application, we obtain an explicit formula expressing
Dedekind sums for Hecke triangle groups in terms of continued fractions.


title: Droplet phase in a nonlocal isoperimetric problem under confinement

abstract:
  We address small volume-fraction asymptotic properties of a nonlocal
isoperimetric functional with a confinement term, derived as the sharp
interface limit of a variational model for self-assembly of diblock copolymers
under confinement by nanoparticle inclusion. We introduce a small parameter
$\eta$ to represent the size of the domains of the minority phase, and study
the resulting droplet regime as $\eta\to 0$. By considering confinement
densities which are spatially variable and attain a nondegenerate maximum, we
present a two-stage asymptotic analysis wherein a separation of length scales
is captured due to competition between the nonlocal repulsive and confining
attractive effects in the energy. A key role is played by a parameter $M$ which
gives the total volume of the droplets at order $\eta^3$ and its relation to
existence and non-existence of Gamow's Liquid Drop model on $\mathbb{R}^3$. For
large values of $M$, the minority phase splits into several droplets at an
intermediate scale $\eta^{1/3}$, while for small $M$ minimizers form a single
droplet converging to the maximum of the confinement density.


title:
A Survey and Taxonomy of Self-Aware and Self-Adaptive Cloud Autoscaling
  Systems

abstract:
  Autoscaling system can reconfigure cloud-based services and applications,
through various configurations of cloud software and provisions of hardware
resources, to adapt to the changing environment at runtime. Such a behavior
offers the foundation for achieving elasticity in modern cloud computing
paradigm. Given the dynamic and uncertain nature of the shared cloud
infrastructure, cloud autoscaling system has been engineered as one of the most
complex, sophisticated and intelligent artifacts created by human, aiming to
achieve self-aware, self-adaptive and dependable runtime scaling. Yet, existing
Self-aware and Self-adaptive Cloud Autoscaling System (SSCAS) is not mature to
a state that it can be reliably exploited in the cloud. In this article, we
survey the state-of-the-art research studies on SSCAS and provide a
comprehensive taxonomy for this field. We present detailed analysis of the
results and provide insights on open challenges, as well as the promising
directions that are worth investigated in the future work of this area of
research. Our survey and taxonomy contribute to the fundamentals of engineering
more intelligent autoscaling systems in the cloud.


title:
Discovery and Precise Characterization by the MEarth Project of LP
  661-13, an Eclipsing Binary Consisting of Two Fully Convective Low-mass Stars

abstract:
  We report the detection of stellar eclipses in the LP 661-13 system. We
present the discovery and characterization of this system, including high
resolution spectroscopic radial velocities and a photometric solution spanning
two observing seasons. LP 661-13 is a low mass binary system with an orbital
period of $4.7043512^{+0.0000013}_{-0.0000010}$ days at a distance of $24.9 \pm
1.3$ parsecs. LP 661-13A is a $0.30795 \pm 0.00084$ $M_\odot$ star while LP
661-13B is a $0.19400 \pm 0.00034$ $M_\odot$ star. The radius of each component
is $0.3226 \pm 0.0033$ $R_\odot$ and $0.2174 \pm 0.0023$ $R_\odot$,
respectively. We detect out of eclipse modulations at a period slightly shorter
than the orbital period, implying that at least one of the components is not
rotating synchronously. We find that each component is slightly inflated
compared to stellar models, and that this cannot be reconciled through age or
metallicity effects. As a nearby eclipsing binary system where both components
are near or below the full-convection limit, LP 661-13 will be a valuable test
of models for the structure of cool dwarf stars.


title:
Hidden Sector Hydrogen as Dark Matter: Small-scale Structure Formation
  Predictions and the Importance of Hyperfine Interactions

abstract:
  We study the atomic physics and the astrophysical implications of a model in
which the dark matter is the analog of hydrogen in a secluded sector. The self
interactions between dark matter particles include both elastic scatterings as
well as inelastic processes due to a hyperfine transition. The self-interaction
cross sections are computed by numerically solving the coupled Schr\"{o}dinger
equations for this system. We show that these self interactions exhibit the
right velocity dependence to explain the low dark matter density cores seen in
small galaxies while being consistent with all constraints from observations of
clusters of galaxies. For a viable solution, the dark hydrogen mass has to be
in 10--100 GeV range and the dark fine-structure constant has to be larger than
0.02. Precisely for this range of parameters, we show that significant cooling
losses may occur due to inelastic excitations to the hyperfine state and
subsequent decays, with implications for the evolution of low-mass halos and
the early growth of supermassive black holes. Cooling from excitations to
higher $n$ levels of dark hydrogen and subsequent decays is possible at the
cluster scale, with a strong dependence on halo mass. Finally, we show that the
minimum halo mass is in the range of $10^{3.5}$ to $10^7 M_\odot$ for the
viable regions of parameter space, significantly larger than the typical
predictions for weakly-interacting dark matter models. This pattern of
observables in cosmological structure formation is unique to this model, making
it possible to rule in or rule out hidden sector hydrogen as a viable dark
matter model.


title:
Lattice rotation vortex at the monoclinic ferroelectric domain boundary
  in relaxor ferroelectric crystal

abstract:
  We present the evidence of lattice rotation vortices having an average radius
of ~7 nm at the monoclinic ferroelectric domain boundary of
(1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-xPT, x=0.08). Maps of crystal orientations,
domain configurations, symmetry breaking are obtained using scanning convergent
beam electron diffraction (SCBED). Such measurements suggest the merging of 2D
and 1D topological defects, with implications for domain-switching mechanisms
in relaxor ferroelectric crystals, and the possibility of a new form of
nanoscale ferroelectric devices.


title: Leptogenesis and neutral gauge bosons

abstract:
  We consider low-scale leptogenesis via right-handed neutrinos $N$ coupled to
a $Z'$ boson, with gauged $U(1)_{B-L}$ as a simple realization. Keeping the
neutrinos sufficiently out of equilibrium puts strong bounds on the $Z'$
coupling strength and mass, our focus being on light $Z'$ and $N$, testable in
the near future by SHiP, HPS, Belle II, and at the LHC. We show that
leptogenesis could be robustly falsified in a large region of parameter space
by the double observation of $Z'$ and $N$, e.g. in the channel $pp\to Z' \to
NN$ with displaced $N$-decay vertex, and by several experiments searching for
light $Z'$, according to the mass of $N$.


title:
The SAMI galaxy survey: Galaxy Interactions and Kinematic Anomalies in
  Abell 119

abstract:
  Galaxy mergers are important events that can determine the fate of a galaxy
by changing its morphology, star-formation activity and mass growth. Merger
systems have commonly been identified from their disturbed morphologies, and we
now can employ Integral Field Spectroscopy to detect and analyze the impact of
mergers on stellar kinematics as well. We visually classified galaxy morphology
using deep images ($\mu_{\rm r} = 28\,\rm mag\,\, arcsec^{-2}$) taken by the
Blanco 4-m telescope at the Cerro Tololo Inter-American Observatory. In this
paper we investigate 63 bright ($M_{\rm r}<-19.3$) spectroscopically-selected
galaxies in Abell 119; of which 53 are early type and 20 galaxies show a
disturbed morphology by visual inspection. A misalignment between the major
axes in the photometric image and the kinematic map is conspicuous in
morphologically-disturbed galaxies. Our sample is dominated by early-type
galaxies, yet it shows a surprisingly tight Tully-Fisher relation except for
the morphologically-disturbed galaxies which show large deviations. Three out
of the eight slow rotators in our sample are morphology disturbed. The
visually-selected morphologically-disturbed galaxies are generally more
asymmetric, visually as well as kinematically. Our findings suggest that galaxy
interactions, including mergers and perhaps fly-bys, play an important role in
determining the orientation and magnitude of galaxy's angular momentum.


title:
Multiplicity-free Kronecker products of characters of the symmetric
  groups

abstract:
  We provide a classification of multiplicity-free inner tensor products of
irreducible characters of symmetric groups, thus confirming a conjecture of
Bessenrodt. Concurrently, we classify all multiplicity-free inner tensor
products of skew characters of the symmetric groups. We also provide formulae
for calculating the decomposition of these tensor products.


title: Hyperelliptic graphs and the period mapping on outer space

abstract:
  The period mapping assigns to each rank n, marked metric graph Gamma a
positive definite quadratic form on H_1(Gamma). This defines maps Phi* and Phi
on Culler--Vogtmann's outer space CV_n, and its Torelli space quotient T_n,
respectively. The map Phi is a free group analog of the classical period
mapping that sends a marked Riemann surface to its Jacobian. In this paper, we
analyze the fibers of Phi in T_n, showing that they are aspherical,
pi_1-injective subspaces. Metric graphs admitting a 'hyperelliptic involution'
play an important role in the structure of Phi, leading us to define the
hyperelliptic Torelli group, ST(n) < Out(F_n). We obtain generators for ST(n),
and apply them to show that the connected components of the locus of
'hyperelliptic' graphs in T_n become simply-connected when certain degenerate
graphs at infinity are added.


title: Dual Matter-Wave Inertial Sensors in Weightlessness

abstract:
  Quantum technology based on cold-atom interferometers is showing great
promise for fields such as inertial sensing and fundamental physics. However,
the best precision achievable on Earth is limited by the free-fall time of the
atoms, and their full potential can only be realized in Space where
interrogation times of many seconds will lead to unprecedented sensitivity.
Various mission scenarios are presently being pursued which plan to implement
matter-wave inertial sensors. Toward this goal, we realize the first onboard
operation of simultaneous $^{87}$Rb $-$ $^{39}$K interferometers in the
weightless environment produced during parabolic flight. The large vibration
levels ($10^{-2}~g/\sqrt{\rm Hz}$), acceleration range ($0-1.8~g$) and rotation
rates ($5$ deg/s) during flight present significant challenges. We demonstrate
the capability of our dual-quantum sensor by measuring the E\"{o}tv\"{o}s
parameter with systematic-limited uncertainties of $1.1 \times 10^{-3}$ and
$3.0 \times 10^{-4}$ during standard- and micro-gravity, respectively. This
constitutes the first test of the equivalence principle in a free-falling
vehicle with quantum sensors. Our results are applicable to inertial
navigation, and can be extended to the trajectory of a satellite for future
Space missions.


title:
On the stability conditions for theories of modified gravity in presence
  of matter fields

abstract:
  We present a thorough stability analysis of modified gravity theories in the
presence of matter fields. We use the Effective Field Theory framework for Dark
Energy and Modified Gravity to retain a general approach for the gravity sector
and a Sorkin-Schutz action for the matter one. Then, we work out the proper
viability conditions to guarantee in the scalar sector the absence of ghosts,
gradient and tachyonic instabilities. The absence of ghosts can be achieved by
demanding a positive kinetic matrix, while the lack of a gradient instability
is ensured by imposing a positive speed of propagation for all the scalar
modes. In case of tachyonic instability, the mass eigenvalues have been studied
and we work out the appropriate expressions. For the latter, an instability
occurs only when the negative mass eigenvalue is much larger, in absolute
value, than the Hubble parameter. We discuss the results for the minimally
coupled quintessence model showing for a particular set of parameters two
typical behaviours which in turn lead to a stable and an unstable
configuration. Moreover, we find that the speeds of propagation of the scalar
modes strongly depend on matter densities, for the beyond Horndeski theories.
Our findings can be directly employed when testing modified gravity theories as
they allow to identify the correct viability space.


title:
Attack-resilient Estimation of Switched Nonlinear Stochastic
  Cyber-Physical Systems

abstract:
  This paper studies attack-resilient estimation of a class of switched
nonlinear systems subject to stochastic noises. The systems are threatened by
both of signal attacks and switching attacks. The problem is formulated as the
joint estimation of states, attack vectors and modes of hidden-mode switched
systems. We propose an estimation algorithm which is composed of a bank of
state and attack vector estimators and a mode estimator. The mode estimator
selects the most likely mode based on modes' posterior probabilities induced by
the discrepancies between obtained outputs and predicted outputs. We formally
analyze the stability of estimation errors in probability for the proposed
estimator associated with the true mode when the hidden mode is time-invariant
but remains unknown. For hidden-mode switched linear systems, we discuss a way
to reduce computational complexity which originates from unknown signal attack
locations. Lastly, we present numerical simulations on the IEEE 68-bus test
system to show the estimator performance for time-varying modes with a regular
mode set and a reduced mode set.


title: Noisy Beam Alignment Techniques for Reciprocal MIMO Channels

abstract:
  Future multi-input multi-output (MIMO) wireless communications systems will
use beamforming as a first-step towards realizing the capacity requirements
necessitated by the exponential increase in data demands. The focus of this
work is on beam alignment for time-division duplexing (TDD) systems, for which
we propose a number of novel algorithms. These algorithms seek to obtain good
estimates of the optimal beamformer/combiner pair (which are the dominant
singular vectors of the channel matrix). They are motivated by the power
method, an iterative algorithm to determine eigenvalues and eigenvectors
through repeated matrix multiplication. In contrast to the basic power method
which considers only the most recent iteration and assumes noiseless links, the
proposed techniques consider information from all the previous iterations of
the algorithm and combine them in different ways. The first technique
(Sequential Least-Squares method) sequentially constructs a least-squares
estimate of the channel matrix, which is then used to calculate the
beamformer/combiner pair estimate. The second technique (Summed Power method)
aims to mitigate the effect of noise by using a linear combination of the
previously tried beams to calculate the next beam, providing improved
performance in the low-SNR regime (typical for mmWave systems) with minimal
complexity/feedback overhead. A third technique (Least-Squares Initialized
Summed Power method) combines the good performance of the first technique at
the high-SNR regime with the low-complexity advantage of the second technique
by priming the summed power method with initial estimates from the sequential
method.


title: Automorphisms and homology of non-positively curved cube complexes

abstract:
  We define an integer-valued invariant of special cube complexes called the
genus, and prove that having genus one characterizes special cube complexes
with abelian fundamental group. Using the genus, we obtain a new proof that the
fundamental group of a special cube complex is either free abelian or surjects
onto a non-cyclic free group. We also investigate automorphisms of special cube
complexes, and give a new geometric proof that the Torelli subgroup for a
right-angled Artin group is torsion-free.


title: Fixed-Point Adiabatic Quantum Search

abstract:
  Fixed-point quantum search algorithms succeed at finding one of $M$ target
items among $N$ total items even when the run time of the algorithm is longer
than necessary. While the famous Grover's algorithm can search quadratically
faster than a classical computer, it lacks the fixed-point property --- the
fraction of target items must be known precisely to know when to terminate the
algorithm. Recently, Yoder, Low, and Chuang gave an optimal gate-model search
algorithm with the fixed-point property. Meanwhile, it is known that an
adiabatic quantum algorithm, operating by continuously varying a Hamiltonian,
can reproduce the quadratic speedup of gate-model Grover search. We ask, can an
adiabatic algorithm also reproduce the fixed-point property? We show that the
answer depends on what interpolation schedule is used, so as in the gate model,
there are both fixed-point and non-fixed-point versions of adiabatic search,
only some of which attain the quadratic quantum speedup. Guided by geometric
intuition on the Bloch sphere, we rigorously justify our claims with an
explicit upper bound on the error in the adiabatic approximation. We also show
that the fixed-point adiabatic search algorithm can be simulated in the gate
model with neither loss of the quadratic Grover speedup nor of the fixed-point
property. Finally, we discuss natural uses of fixed-point algorithms such as
preparation of a relatively prime state and oblivious amplitude amplification.


title: Graphene Electronic Structure in Charge Density Waves

abstract:
  We introduce the idea that the electronic band structure of a charge density
wave system may mimic the electronic structure of graphene. In that case a
class of materials quite different from graphene might be opened up to exploit
graphene's remarkable electronic properties. The theory of such materials,
along with superconductivity, is based on the material's dynamical, rather than
its static, properties. The charge density wave system turns out to have a
number of requirements: (1) a specific wave geometry simply related to
graphene; (2) a self-consistency among the electrons that requires the net
Coulomb and phonon-mediated parts of the electron-electron interactions to be
attractive. We develop a model that leads to an analytical expression for the
total energy in terms of the effective electron mass $\mu$, the electron
density $\rho_0$, and the strength $\tilde{\nu}_{K}$ of the net
electron-electron interaction. For constant $\mu>0$ and $\rho_0$, we examine
the limitations set upon $\tilde{\nu}_{K}$ by self-consistency, stability, and
the approximation in the electronic state calculation, and find them to be
mutually compatible. This demonstrates the viability of our model.


title: Detecting Text in Natural Image with Connectionist Text Proposal Network

abstract:
  We propose a novel Connectionist Text Proposal Network (CTPN) that accurately
localizes text lines in natural image. The CTPN detects a text line in a
sequence of fine-scale text proposals directly in convolutional feature maps.
We develop a vertical anchor mechanism that jointly predicts location and
text/non-text score of each fixed-width proposal, considerably improving
localization accuracy. The sequential proposals are naturally connected by a
recurrent neural network, which is seamlessly incorporated into the
convolutional network, resulting in an end-to-end trainable model. This allows
the CTPN to explore rich context information of image, making it powerful to
detect extremely ambiguous text. The CTPN works reliably on multi-scale and
multi- language text without further post-processing, departing from previous
bottom-up methods requiring multi-step post-processing. It achieves 0.88 and
0.61 F-measure on the ICDAR 2013 and 2015 benchmarks, surpass- ing recent
results [8, 35] by a large margin. The CTPN is computationally efficient with
0:14s/image, by using the very deep VGG16 model [27]. Online demo is available
at: http://textdet.com/.


title:
Semiclassical Hartree-Fock theory of a rotating Bose-Einstein
  condensation

abstract:
  In this paper, we investigate the thermodynamic behavior of a rotating
Bose-Einstein condensation with non-zero interatomic interactions
theoretically. The analysis relies on a semiclassical Hartree-Fock
approximation where an integral is performed over the phase space and function
of the grand canonical ensemble is derived. Subsequently, we use this result to
derive several thermodynamic quantities including the condensate fraction,
critical temperature, entropy and heat capacity. Thereby, we investigate the
effect of the rotation rate and interactions parameter on the thermodynamic
behavior. The role of finite size is discussed. Our approach can be extended to
consider the rotating condensate in optical potential.


title: An ultra-low noise, high-voltage piezo driver

abstract:
  We present an ultra-low noise, high-voltage driver suited for use with
piezoelectric actuators and other low-current applications. The architecture
uses a flyback switching regulator to generate up to 250V in our current
design, with an output of 1 kV or more possible with small modifications. A
high slew-rate op-amp suppresses the residual switching noise, yielding a total
RMS noise of $\approx 100\mu$V (1 Hz--100 kHz). A low-voltage ($\pm 10$V), high
bandwidth signal can be summed with unity gain directly onto the output, making
the driver well-suited for closed-loop feedback applications. Digital control
enables both repeatable setpoints and sophisticated control logic, and the
circuit consumes less than 150mA at $\pm 15$V.


title: A classification result for the quasi-linear Liouville equation

abstract:
  Entire solutions of the $n-$Laplace Liouville equation in $\mathbb{R}^n$ with
finite mass are completely classified.


title:
Estimation of spin relaxation lengths in spin valves of In and In2O3
  nanostructures

abstract:
  We report the electrical injection and detection of spin polarized current in
lateral ferromagnet-nonmagnet-ferromagnet spin valve devices, ferromagnet being
cobalt and nonmagnet being indium (In) or indium oxide (In2O3) nanostructures.
The In nanostructures were grown by depositing pure In on lithographically
pre-patterned structures. In2O3 nanostructures were obtained by oxidation of In
nanostructures. Spin valve devices were fabricated by depositing micro magnets
over the nanostructures with connecting nonmagnetic electrodes via two steps of
e-beam lithography. Clear spin switching behavior was observed in the both
types of spin valve devices measured at 10 K. From the measured spin signal,
the spin relaxation length ({\lambda}N) of In and In2O3 nanostructures were
estimated to be 449.6 nm and 788.6 nm respectively.


title:
Non-Escaping Sets in Conformal Dynamical Systems and Singular
  Perturbations of Perron-Frobenius Operators

abstract:
  The study of escape rates for a ball in a dynamical systems has been much
studied. Understanding the asymptotic behavior of the escape rate as the radius
of the ball tends to zero is an especially subtle problem. In the case of
hyperbolic conformal systems this has been addressed by various authors. In
this paper we consider a far more general realm of conformal maps where the
analysis is correspondingly more complicated. We prove the existence of escape
rates and calculate them in the context of countable alphabets, either finite
or infinite, uniformly contracting conformal graph directed Markov systems with
their special case of conformal countable alphabet iterated function systems.
This goal is achieved by developing the appropriate theory of singular
perturbations of Perron-Frobenius (transfer) operators associated with
countable alphabet subshifts of finite type and H\"older continuous summable
potentials. This is the key ingredient for further results about other
conformal systems. These include topological Collet-Eckmann multimodal interval
maps and rational maps of the Riemann sphere (an equivalent formulation is to
be uniformly hyperbolic on periodic points), and also a large class of
transcendental meromorphic functions.


title: Relativistic axions from collapsing Bose stars

abstract:
  The substructures of light bosonic (axion-like) dark matter may condense into
compact Bose stars. We study collapses of the critical-mass stars caused by
attractive self-interaction of the axion-like particles and find that these
processes proceed in an unexpected universal way. First, nonlinear self-similar
evolution (called "wave collapse" in condensed matter physics) forces the
particles to fall into the star center. Second, interactions in the dense
center create an outgoing stream of mildly relativistic particles which carries
away an essential part of the star mass. The collapse stops when the star
remnant is no longer able to support the self-similar infall feeding the
collisions. We shortly discuss possible astrophysical and cosmological
implications of these phenomena.


title:
Topological Magnon Bands and Unconventional Superconductivity in
  Pyrochlore Iridate Thin Films

abstract:
  We theoretically study the magnetic properties of pyrochlore iridate bilayer
and trilayer thin films grown along the $[111]$ direction using a strong
coupling approach. We find the ground state magnetic configurations on a mean
field level and carry out a spin-wave analysis about them. In the trilayer case
the ground state is found to be the all-in-all-out (AIAO) state, whereas the
bilayer has a deformed AIAO state. For all parameters of the spin-orbit coupled
Hamiltonian we study, the lowest magnon band in the trilayer case has a nonzero
Chern number. In the bilayer case we also find a parameter range with nonzero
Chern numbers. We calculate the magnon Hall response for both geometries,
finding a striking sign change as function of temperature. Using a slave-boson
mean-field theory we study the doping of the trilayer system and discover an
unconventional time-reversal symmetry broken $d+id$ superconducting state. Our
study complements prior work in the weak coupling limit and suggests that the
$[111]$ grown thin film pyrochlore iridates are a promising candidate for
topological properties and unconventional orders.


title:
Solar System constraints on Renormalization Group extended General
  Relativity: The PPN and Laplace-Runge-Lenz analyses with the external
  potential effect

abstract:
  General Relativity extensions based on Renormalization Group effects are
motivated by a known physical principle and constitute a class of extended
gravity theories that have some unexplored unique aspects. In this work we
develop in detail the Newtonian and post Newtonian limits of a realisation
called Renormalization Group extended General Relativity (RGGR). Special
attention is taken to the external potential effect, which constitutes a type
of screening mechanism typical of RGGR. In the Solar System, RGGR depends on a
single dimensionless parameter $\bar \nu_\odot$, and this parameter is such
that for $\bar \nu_\odot = 0$ one fully recovers GR in the Solar System.
Previously this parameter was constrained to be $|\bar \nu_\odot| \lesssim
10^{-21}$, without considering the external potential effect. Here we show that
under a certain approximation RGGR can be cast in a form compatible with the
Parametrised Post-Newtonian (PPN) formalism, and we use both the PPN formalism
and the Laplace-Runge-Lenz technique to put new bounds on $\bar \nu_\odot$,
either considering or not the external potential effect. With the external
potential effect the new bound reads $|\bar \nu_\odot| \lesssim 10^{-16}$. We
discuss the possible consequences of this bound to the dark matter abundance in
galaxies.


title: Less is More: Minimizing Code Reorganization using XTREE

abstract:
  Context: Developers use bad code smells to guide code reorganization. Yet
developers, text books, tools, and researchers disagree on which bad smells are
important. Objective: To evaluate the likelihood that a code reorganization to
address bad code smells will yield improvement in the defect-proneness of the
code. Method: We introduce XTREE, a tool that analyzes a historical log of
defects seen previously in the code and generates a set of useful code changes.
Any bad smell that requires changes outside of that set can be deprioritized
(since there is no historical evidence that the bad smell causes any problems).
Evaluation: We evaluate XTREE's recommendations for bad smell improvement
against recommendations from previous work (Shatnawi, Alves, and Borges) using
multiple data sets of code metrics and defect counts. Results: Code modules
that are changed in response to XTREE's recommendations contain significantly
fewer defects than recommendations from previous studies. Further, XTREE
endorses changes to very few code metrics, and the bad smell recommendations
(learned from previous studies) are not universal to all software projects.
Conclusion: Before undertaking a code reorganization based on a bad smell
report, use a tool like XTREE to check and ignore any such operations that are
useless; i.e. ones which lack evidence in the historical record that it is
useful to make that change. Note that this use case applies to both manual code
reorganizations proposed by developers as well as those conducted by automatic
methods. This recommendation assumes that there is an historical record. If
none exists, then the results of this paper could be used as a guide.


title:
Integrated, reliable and cloud-based personal health record: A scoping
  review

abstract:
  Personal Health Records (PHR) emerge as an alternative to integrate patient's
health information to give a global view of patients' status. However,
integration is not a trivial feature when dealing with a variety electronic
health systems from healthcare centers. Access to PHR sensitive information
must comply with privacy policies defined by the patient. Architecture PHR
design should be in accordance to these, and take advantage of nowadays
technology. Cloud computing is a current technology that provides scalability,
ubiquity, and elasticity features. This paper presents a scoping review related
to PHR systems that achieve three characteristics: integrated, reliable and
cloud-based. We found 101 articles that addressed those characteristics. We
identified four main research topics: proposal/developed systems, PHR
recommendations for development, system integration and standards, and security
and privacy. Integration is tackled with HL7 CDA standard. Information
reliability is based in ABE security-privacy mechanism. Cloud-based technology
access is achieved via SOA.


title: Reciprocity maps with restricted ramification

abstract:
  We compare two maps that arise in study of the cohomology of number fields
with ramification restricted to a finite set S of primes. One of these maps,
which we call an S-reciprocity map, interpolates the values of cup products in
S-ramified cohomology. In the case of p-ramified cohomology of the pth
cyclotomic field for an odd prime p, we use this to exhibit an intriguing
relationship between particular values of the cup product on cyclotomic
p-units. We then consider higher analogues of the S-reciprocity map and relate
their cokernels to the graded quotients in augmentation filtrations of Iwasawa
modules.


title: The Build-Up of Diversity in Complex Ecosystems

abstract:
  Diversity is a fundamental feature of ecosystems, even when the concept of
ecosystem is extended to sociology or economics. Diversity can be intended as
the count of different items, animals, or, more generally, interactions. There
are two classes of stylized facts that emerge when diversity is taken into
account. The first are Diversity explosions: evolutionary radiations in
biology, or the process of escaping 'Poverty Traps' in economics are two well
known examples. The second is nestedness: entities with a very diverse set of
interactions are the only ones that interact with more specialized ones. In a
single sentence: specialists interact with generalists. Nestedness is observed
in a variety of bipartite networks of interactions: Biogeographic,
macroeconomic and mutualistic to name a few. This indicates that entities
diversify following a pattern. Since they appear in such very different
systems, these two stylized facts point out that the build up of diversity is
driven by a fundamental probabilistic mechanism, and here we sketch its minimal
features. We show how the contraction of a random tripartite network, which is
maximally entropic in all its degree distributions but one, can reproduce
stylized facts of real data with great accuracy which is qualitatively lost
when that degree distribution is changed. We base our reasoning on the
combinatoric picture that the nodes on one layer of these bipartite networks
can be described as combinations of a number of fundamental building blocks.
The stylized facts of diversity that we observe in real systems can be
explained with an extreme heterogeneity (a scale-free distribution) in the
number of meaningful combinations in which each building block is involved. We
show that if the usefulness of the building blocks has a scale-free
distribution, then maximally entropic baskets of building blocks will give rise
to very rich behaviors.


title: Toric quiver cells

abstract:
  It is shown that up to dimension four, the toric ideal of a quiver polytope
is generated in degree two, with the only exception of the four-dimensional
Birkhoff polytope. As a consequence, B{\o}gvad's conjecture holds for quiver
polytopes of dimension at most four. In arbitrary dimension, the toric ideal of
a compressed polytope is generated in degree two if the polytope has no
neighbouring singular vertices. Furthermore, the toric ideal of a compressed
polytope with at most one singular vertex has a quadratic Gr\"obner basis.


title:
Reliable Attribute-Based Object Recognition Using High Predictive Value
  Classifiers

abstract:
  We consider the problem of object recognition in 3D using an ensemble of
attribute-based classifiers. We propose two new concepts to improve
classification in practical situations, and show their implementation in an
approach implemented for recognition from point-cloud data. First, the viewing
conditions can have a strong influence on classification performance. We study
the impact of the distance between the camera and the object and propose an
approach to fuse multiple attribute classifiers, which incorporates distance
into the decision making. Second, lack of representative training samples often
makes it difficult to learn the optimal threshold value for best positive and
negative detection rate. We address this issue, by setting in our attribute
classifiers instead of just one threshold value, two threshold values to
distinguish a positive, a negative and an uncertainty class, and we prove the
theoretical correctness of this approach. Empirical studies demonstrate the
effectiveness and feasibility of the proposed concepts.


title: Circuit Covers of Cubic Signed Graphs

abstract:
  A signed graph is a graph $G$ associated with a mapping $\sigma: E(G)\to
\{-1,+1\}$, denoted by $(G,\sigma)$. A $cycle$ of $(G,\sigma)$ is a connected
2-regular subgraph. A cycle $C$ is $positive$ if it has an even number of
negative edges, and negative otherwise. A $circuit$ of of a signed graph
$(G,\sigma)$ is a positive cycle or a barbell consisting of two edge-disjoint
negative cycles joined by a path. The definition of a circuit of signed graph
comes from the signed-graphic matroid. A circuit cover of $(G,\sigma)$ is a
family of circuits covering all edges of $(G,\sigma)$. A circuit cover with the
smallest total length is called a shortest circuit cover of $(G,\sigma)$ and
its length is denoted by $\text{scc}(G,\sigma)$. Bouchet proved that a signed
graph with a circuit cover if and only if it is flow-admissible (i.e., has a
nowhere-zero integer flow). M\'a\v{c}ajov\'a et. al. show that a
2-edge-connected signed graph $(G,\sigma)$ has $\text{scc}(G,\sigma)\le 9
|E(G)|$ if it is flow-admissible. This bound was improved recently by Cheng et.
al. to $\text{scc}(G,\sigma) \le 11|E(G)|/3$ for 2-edge-connected signed graphs
with even negativeness, and particularly, $\text{scc}(G,\sigma)\le
3|E(G)|+\epsilon(G,\sigma)/3$ for 2-edge-connected cubic signed graphs with
even negativeness (where $\epsilon(G,\sigma)$ is the negativeness of
$(G,\sigma)$). In this paper, we show that every 2-edge-connected cubic signed
graph has $\text{scc}(G,\sigma)\le 26|E(G)|/9$ if it is flow-admissible, and
$\text{scc}(G,\sigma)\le 23|E(G)|/9$ if it has even negativeness.


title: An extension of Nikishin's factorization theorem

abstract:
  A Nikishin-Maurey characterization is given for bounded subsets of weak-type
Lebesgue spaces. New factorizations for linear and multilinear operators are
shown to follow.


title:
A Computational Analysis of the Function of Three Inhibitory Cell Types
  in Contextual Visual Processing

abstract:
  Most cortical inhibitory cell types exclusively express one of three genes,
parvalbumin, somatostatin and 5HT3a. The visual responses of cortical neurons
are affected not only by local cues, but also by visual context. As the
inhibitory neuron types have distinctive synaptic sources and targets over
different spatial extents and from different areas, we conjecture that they
possess distinct roles in contextual processing. We use modeling to relate
structural information to function in primary visual cortex (V1) of the mouse,
and investigate their role in contextual visual processing. Our findings are
threefold. First, the inhibition mediated by parvalbumin positive (PV) cells
mediates local processing and could underlie their role in boundary detection.
Second, the inhibition mediated by somatostatin-positive (SST) cells
facilitates longer range spatial competition among receptive fields. Third,
non-specific top-down modulation to interneurons expressing vasoactive
intestinal polypeptide (VIP), a subclass of 5HT3a neurons, can selectively
enhance V1 responses.


title: Elements of Torelli topology: I. The rank of abelian subgroups

abstract:
  By Torelli topology the author understands aspects of the topology of
surfaces (potentially) relevant to the study of Torelli groups. The present
paper is devoted to a new approach to the results of W. Vautaw about Dehn
multi-twists in Torelli groups and abelian subgroups of Torelli groups. The new
proofs are more transparent and lead to stronger estimates of the rank of an
abelian subgroup when some additional information is available. An unexpected
application of our methods is a new proof of the algebraic characterization of
the Dehn twist about separating circles and the Dehn-Johnson twists about
bounding pairs of circles. This proof is much shorter than the original one and
bypasses one of the main difficulties, which may be called the extension
problem, specific to Torelli groups as opposed to the Teichm\"uller modular
groups. The extension problem is discussed in details in the second paper of
this series.


title: Rost invariant on the center, revisited

abstract:
  The Rost invariant of the Galois cohomology of a simple simply connected
algebraic group over a field $F$ is defined regardless of the characteristic of
$F$, but unfortunately some formulas for it are only known with some hypothesis
on the the characteristic. We improve those formulas by (1) removing the
hypothesis on the characteristic and (2) removing an ad hoc pairing that
appears in the original formulas. As a preliminary step of independent
interest, we also extend the classification of invariants of quasi-trivial tori
to all fields.


title: A varifold approach to surface approximation

abstract:
  We show that the theory of varifolds can be suitably enriched to open the way
to applications in the field of discrete and computational geometry. Using
appropriate regularizations of the mass and of the first variation of a
varifold we introduce the notion of approximate mean curvature and show various
convergence results that hold in particular for sequences of discrete varifolds
associated with point clouds or pixel/voxel-type discretizations of
$d$-surfaces in the Euclidean $n$-space, without restrictions on dimension and
codimension. The variational nature of the approach also allows to consider
surfaces with singularities, and in that case the approximate mean curvature is
consistent with the generalized mean curvature of the limit surface. A series
of numerical tests are provided in order to illustrate the effectiveness and
generality of the method.


title:
Convergence Rates of Inertial Splitting Schemes for Nonconvex Composite
  Optimization

abstract:
  We study the convergence properties of a general inertial first-order
proximal splitting algorithm for solving nonconvex nonsmooth optimization
problems. Using the Kurdyka--\L ojaziewicz (KL) inequality we establish new
convergence rates which apply to several inertial algorithms in the literature.
Our basic assumption is that the objective function is semialgebraic, which
lends our results broad applicability in the fields of signal processing and
machine learning. The convergence rates depend on the exponent of the
"desingularizing function" arising in the KL inequality. Depending on this
exponent, convergence may be finite, linear, or sublinear and of the form
$O(k^{-p})$ for $p>1$.


title:
$SU(1,1)$ solution for the Dunkl-Coulomb problem in two dimensions and
  its coherent states

abstract:
  We study the radial part of the Dunkl-Coulomb problem in two dimensions and
show that this problem possesses the $su(1,1)$ symmetry. We introduce two
different realizations for the $su(1,1)$ Lie algebra and use the theory of
irreducible representations to obtain the energy spectrum and the
eigenfunctions. For the first algebra realization, we apply the Schr\"odinger
factorization to the radial part of the Dunkl-Coulomb problem to construct the
algebra generators. In the second realization, we introduce three operators,
been one of them proportional to the radial Hamiltonian. Finally, we use the
$su(1,1)$ Sturmian basis of one of the two algebras to construct the radial
coherent states in a closed form.


title: Co-active Learning to Adapt Humanoid Movement for Manipulation

abstract:
  In this paper we address the problem of robot movement adaptation under
various environmental constraints interactively. Motion primitives are
generally adopted to generate target motion from demonstrations. However, their
generalization capability is weak while facing novel environments.
Additionally, traditional motion generation methods do not consider the
versatile constraints from various users, tasks, and environments. In this
work, we propose a co-active learning framework for learning to adapt robot
end-effector's movement for manipulation tasks. It is designed to adapt the
original imitation trajectories, which are learned from demonstrations, to
novel situations with various constraints. The framework also considers user's
feedback towards the adapted trajectories, and it learns to adapt movement
through human-in-the-loop interactions. The implemented system generalizes
trained motion primitives to various situations with different constraints
considering user preferences. Experiments on a humanoid platform validate the
effectiveness of our approach.


title: Wireless Security with Beamforming Technique

abstract:
  This thesis focuses on the wireless security in the physical layer with
beamforming technique. One of the emerging areas is the security enhancement in
the physical layer, which exploits the intrinsic properties of the wireless
medium. Beamforming, which has been proved to have many advantages, can also be
applied to enhance the wireless security.
  One of the most common threats, i.e., passive eavesdropping, is addressed in
this thesis. To reduce the risk of leaking information to the eavesdroppers,
the physical region where the transmission is exposed to eavesdropping has been
studied. In this thesis, the exposure region based beamforming technique is
proposed to combat the threat from the randomly located eavesdroppers in a
fading channel. In this system model, the large-scale path loss and a general
Rician fading channel model are considered. The exposure region is established
to describe the secrecy performance of the system, based on which the
probability that the secrecy outage event occurs is defined to evaluate the
security level of the exposure region.
  The antenna array is one of the most important factors that affect the
secrecy performance of the exposure region based beamforming technique. The
potential of using different array geometry and array configuration to improve
security is explored. In this thesis, two common arrays, i.e., linear and
circular arrays, are considered.Analytic expressions for general array geometry
and for the linear and circular arrays are derived. Based on the empirical
results, numerical optimization algorithms are developed to exploit the array
configuration to enhance the system security level. In addition, experiments
are carried out to study the performance of the beamformer with linear and
circular arrays. Especially, the impact of the mutual coupling on the security
performance is investigated.


title:
Equations for spinning test particles in equatorial orbits when they are
  orbiting in a weak rotating field

abstract:
  This paper formulates, via the Mathisson - Papapetrou - Dixon equations, the
system of equations for a test particle with spin when it is orbiting a weak
Kerr metric. We shall restrict ourselves to the case of circular orbits with
the purpose of comparing our results with the results of the literature. In
particular, we solve the set of equations of motion for the case of circular
trajectories both spinless and spinning test particles around rotating bodies
in equatorial plane. The results obtained are an important guideline for the
study of the effects of the particles with spin in rotating gravitational
fields such as Gravitomagnetics Effects or gravitational waves.


title:
A spectral refinement of the Bergelson-Host-Kra decomposition and new
  multiple ergodic theorems

abstract:
  We investigate how spectral properties of a measure preserving system
$(X,\mathcal{B},\mu,T)$ are reflected in the multiple ergodic averages arising
from that system. For certain sequences $a:\mathbb{N}\to\mathbb{N}$ we provide
natural conditions on the spectrum $\sigma(T)$ such that for all
$f_1,\ldots,f_k\in L^\infty$, \begin{equation*} \lim_{N\to\infty} \frac{1}{N}
\sum_{n=1}^N \prod_{j=1}^k T^{ja(n)}f_j = \lim_{N\rightarrow\infty} \frac{1}{N}
\sum_{n=1}^N \prod_{j=1}^k T^{jn}f_j \end{equation*} in $L^2$-norm. In
particular, our results apply to infinite arithmetic progressions $a(n)=qn+r$,
Beatty sequences $a(n)=\lfloor \theta n+\gamma\rfloor$, the sequence of
squarefree numbers $a(n)=q_n$, and the sequence of prime numbers $a(n)=p_n$. We
also obtain a new refinement of Szemer\'edi's theorem via Furstenberg's
correspondence principle.
  ERRATUM: Theorem 7.1 in the paper is incorrect as stated, and the error
originates with Proposition 7.5, part (iii), which was incorrectly quoted from
the literature. In the attached erratum we fix the problem by establishing a
slightly weaker version of Theorem 7.1 and use it to give a new proof of
Theorem 4.2. This ensures that all main results in our main article remain
correct. We thank Zhengxing Lian and Jiahao Qiu for bringing this mistake to
our attention.


title: Joint Extraction of Events and Entities within a Document Context

abstract:
  Events and entities are closely related; entities are often actors or
participants in events and events without entities are uncommon. The
interpretation of events and entities is highly contextually dependent.
Existing work in information extraction typically models events separately from
entities, and performs inference at the sentence level, ignoring the rest of
the document. In this paper, we propose a novel approach that models the
dependencies among variables of events, entities, and their relations, and
performs joint inference of these variables across a document. The goal is to
enable access to document-level contextual information and facilitate
context-aware predictions. We demonstrate that our approach substantially
outperforms the state-of-the-art methods for event extraction as well as a
strong baseline for entity extraction.


title: Using Periodicity to Obtain Partition Congruences

abstract:
  In this paper, we generalize recent work of Mizuhara, Sellers, and Swisher
that gives a method for establishing restricted plane partition congruences
based on a bounded number of calculations. Using periodicity for partition
functions, our extended technique could be a useful tool to prove congruences
for certain types of combinatorial functions based on a bounded number of
calculations. As applications of our result, we establish new and existing
restricted plane partition congruences, restricted plane overpartition
congruences and several examples of restricted partition congruences.


title: Weakly amenable groups

abstract:
  In this paper, a group is called weakly amenable if its left regular
representation is not uniformly isolated from the trivial representation. First
examples of finitely generated non-amenable weakly amenable groups are
constructed.


title: Right Bousfield Localization and Eilenberg-Moore Categories

abstract:
  We compare several recent approaches to studying right Bousfield localization
and algebras over monads. We prove these approaches are equivalent, and we
apply this equivalence to obtain several new results regarding right Bousfield
localizations (some classical, some new) for spectra, spaces, equivariant
spaces, chain complexes, simplicial abelian groups, and the stable module
category. En route, we provide conditions so that right Bousfield localization
lifts to categories of algebras, so that right Bousfield localization preserves
algebras over monads, and so that right Bousfield localization forms a
compactly generated model category.


title:
Theta divisors of abelian varieties and push-forward homomorphism at the
  level of Chow groups

abstract:
  In this text we prove that if an abelian variety $A$ admits of an embedding
into the Jacobian of a smooth projective curve $C$, and if we consider $\Th_A$
to be the divisor $\Th_C\cap A$, where $\Th_C$ denotes the theta divisor of
$J(C)$, then the embedding of $\Th_A$ into $A$ induces an injective
push-forward homomorphism at the level of Chow groups. We show that this is the
case for every principally polarized abelian varieties.


title:
A new search for the $K_{L} \to \pi^0 \nu \overline{\nu}$ and $K_{L} \to
  \pi^{0} X^{0}$ decays

abstract:
  We searched for the $CP$-violating rare decay of neutral kaon, $K_{L} \to
\pi^0 \nu \overline{\nu}$, in data from the first 100 hours of physics running
in 2013 of the J-PARC KOTO experiment. One candidate event was observed while
$0.34\pm0.16$ background events were expected. We set an upper limit of
$5.1\times10^{-8}$ for the branching fraction at the 90\% confidence level
(C.L.). An upper limit of $3.7\times10^{-8}$ at the 90\% C.L. for the $K_{L}
\to \pi^{0} X^{0}$decay was also set for the first time, where $X^{0}$ is an
invisible particle with a mass of 135 MeV/$c^{2}$.


title: Monodromy and algebraic cycles

abstract:
  In this text we are going to discuss the relation between monodromy and
algebraic cycles.


title: Progenitors of type Ia supernovae

abstract:
  Natures of progenitors of type Ia Supernovae (SNe Ia) have not yet been
clarified. There has been long and intensive discussion on whether the
so-called single degenerate (SD) scenario or the double degenerate (DD)
scenario, or anything else, could explain a major population of SNe Ia, but the
conclusion has not yet been reached. With rapidly increasing observational data
and new theoretical ideas, the field of studying the SN Ia progenitors has been
quickly developing, and various new insights have been obtained in recent
years. This article aims at providing a summary of the current situation
regarding the SN Ia progenitors, both in theory and observations. It seems
difficult to explain the emerging diversity seen in observations of SNe Ia by a
single population, and we emphasize that it is important to clarify links
between different progenitor scenarios and different sub-classes of SNe Ia.


title: Compiling Process Networks to Interaction Nets

abstract:
  Kahn process networks are a model of computation based on a collection of
sequential, deterministic processes that communicate by sending messages
through unbounded channels. They are well suited for modelling stream-based
computations, but are in no way restricted to this application. Interaction
nets are graph rewriting systems that have many interesting properties for
implementation. In this paper we show how to encode process networks using
interaction nets, where we model both networks and messages in the same
framework.


title: In-place Graph Rewriting with Interaction Nets

abstract:
  An algorithm is in-place, or runs in-situ, when it does not need any
additional memory to execute beyond a small constant amount. There are many
algorithms that are efficient because of this feature, therefore it is an
important aspect of an algorithm. In most programming languages, it is not
obvious when an algorithm can run in-place, and moreover it is often not clear
that the implementation respects that idea. In this paper we study interaction
nets as a formalism where we can see directly, visually, that an algorithm is
in-place, and moreover the implementation will respect that it is in-place. Not
all algorithms can run in-place however. We can nevertheless still use the same
language, but now we can annotate parts of the algorithm that can run in-place.
We suggest an annotation for rules, and give an algorithm to find this
automatically through analysis of the interaction rules.


title: Kruskal's Tree Theorem for Acyclic Term Graphs

abstract:
  In this paper we study termination of term graph rewriting, where we restrict
our attention to acyclic term graphs. Motivated by earlier work by Plump we aim
at a definition of the notion of simplification order for acyclic term graphs.
For this we adapt the homeomorphic embedding relation to term graphs. In
contrast to earlier extensions, our notion is inspired by morphisms. Based on
this, we establish a variant of Kruskal's Tree Theorem formulated for acyclic
term graphs. In proof, we rely on the new notion of embedding and follow
Nash-Williams' minimal bad sequence argument. Finally, we propose a variant of
the lexicographic path order for acyclic term graphs.


title: Reasoning about Graph Programs

abstract:
  GP 2 is a non-deterministic programming language for computing by graph
transformation. One of the design goals for GP 2 is syntactic and semantic
simplicity, to facilitate formal reasoning about programs. In this paper, we
demonstrate with four case studies how programmers can prove termination and
partial correctness of their solutions. We argue that GP 2's graph
transformation rules, together with induction on the length of program
executions, provide a convenient framework for program verification.


title: Token-passing Optimal Reduction with Embedded Read-back

abstract:
  We introduce a new interaction net implementation of optimal reduction for
the pure untyped lambda calculus. Unlike others, our implementation allows to
reach normal form regardless of the interaction net reduction strategy using
the approach of so-called token-passing nets and a non-deterministic extension
for interaction nets. Another new feature is the read-back mechanism
implemented without leaving the formalism of interaction nets.


title: Efficient Completion of Weighted Automata

abstract:
  We consider directed graphs with edge labels from a semiring. We present an
algorithm that allows efficient execution of queries for existence and weights
of paths, and allows updates of the graph: adding nodes and edges, and changing
weights of existing edges.
  We apply this method in the construction of matchbound certificates for
automatically proving termination of string rewriting. We re-implement the
decomposition/completion algorithm of Endrullis et al. (2006) in our framework,
and achieve comparable performance.


title:
Temperature fluctuations in canonical systems: Insights from molecular
  dynamics simulations

abstract:
  Molecular dynamics simulations of a quasi-harmonic solid are conducted to
elucidate the meaning of temperature fluctuations in canonical systems and
validate a well-known but frequently contested equation predicting the mean
square of such fluctuations. The simulations implement two virtual and one
physical (natural) thermostat and examine the kinetic, potential and total
energy correlation functions in the time and frequency domains. The results
clearly demonstrate the existence of quasi-equilibrium states in which the
system can be characterized by a well-defined temperature that follows the
mentioned fluctuation equation. The emergence of such states is due to the wide
separation of timescales between thermal relaxation by phonon scattering and
slow energy exchanges with the thermostat. The quasi-equilibrium states exist
between these two timescales when the system behaves as virtually isolated and
equilibrium.


title:
Introducing Distributed Dynamic Data-intensive (D3) Science:
  Understanding Applications and Infrastructure

abstract:
  A common feature across many science and engineering applications is the
amount and diversity of data and computation that must be integrated to yield
insights. Data sets are growing larger and becoming distributed; and their
location, availability and properties are often time-dependent. Collectively,
these characteristics give rise to dynamic distributed data-intensive
applications. While "static" data applications have received significant
attention, the characteristics, requirements, and software systems for the
analysis of large volumes of dynamic, distributed data, and data-intensive
applications have received relatively less attention. This paper surveys
several representative dynamic distributed data-intensive application
scenarios, provides a common conceptual framework to understand them, and
examines the infrastructure used in support of applications.


title:
Proceedings of the Seventh International Symposium on Games, Automata,
  Logics and Formal Verification

abstract:
  This volume contains the proceedings of the Seventh International Symposium
on Games, Automata, Logic and Formal Verification (GandALF 2016). The symposium
took place in Catania, Italy, from the 14th to the 16th of September 2016. The
proceedings of the symposium contain abstracts of the 3 invited talks and 21
full papers that were accepted after a careful evaluation for presentation at
the conference. The topics of the accepted papers cover algorithmic game
theory, automata theory, synthesis, formal verification, and dynamic, modal and
temporal logics.


title:
Topological insulators in ordered double transition metals
  M$'_2$M$"$C$_2$ (M$'$= Mo, W; M$"$= Ti, Zr, Hf) MXenes

abstract:
  The family of two-dimensional transition metal carbides, so called MXenes,
has recently found new members with ordered double transition metals
M$'_2$M$"$C$_2$, where M$'$ and M$"$ stand for transition metals. Here, using a
set of first-principles calculations, we demonstrate that some of the newly
added members, oxide M$'_2$M$"$C$_2$ (M$'$= Mo, W; M$"$= Ti, Zr, Hf) MXenes,
are topological insulators. The nontrivial topological states of the predicted
MXenes are revealed by the $Z_2$ index, which is evaluated from the parities of
the occupied bands below the Fermi energy at time reversal invariant momenta,
and also by the presence of the edge states. The predicted M$'_2$M$"$C$_2$O$_2$
MXenes show nontrivial gaps in the range of 0.041 -- 0.285 eV within the
generalized gradient approximation and 0.119 -- 0.409 eV within the hybrid
functional. The band gaps are induced by the spin-orbit coupling within the
degenerate states with $d_{x^2-y^2}$ and $d_{xy}$ characters of M$'$ and M$"$,
while the band inversion occurs at the $\Gamma$ point among the degenerate
$d_{x^2-y^2}$/$d_{xy}$ orbitals and a non-degenerate $d_{3z^2-r^2}$ orbital,
which is driven by the hybridization of the neighboring orbitals. The phonon
dispersion calculations find that the predicted topological insulators are
structurally stable.
  The predicted W-based MXenes with large band gaps might be suitable
candidates for many topological applications at room temperature. In addition,
we study the electronic structures of thicker ordered double transition metals
M$'_2$M$"_2$C$_3$O$_2$ (M$'$= Mo, W; M$"$= Ti, Zr, Hf) and find that they are
nontrivial topological semimetals.


title:
Extreme Quantum Advantage when Simulating Strongly Coupled Classical
  Systems

abstract:
  Classical stochastic processes can be generated by quantum simulators instead
of the more standard classical ones, such as hidden Markov models. One reason
for using quantum simulators is that they generally require less memory than
their classical counterparts. Here, we examine this quantum advantage for
strongly coupled spin systems---the Dyson-like one-dimensional Ising spin chain
with variable interaction length. We find that the advantage scales with both
interaction range and temperature, growing without bound as interaction
increases. Thus, quantum systems can very efficiently simulate strongly coupled
classical systems.

categories: quant-ph cond-mat.stat-mech cs.CC cs.IT math.IT


title: Discussion of Entanglement Entropy in Quantum Gravity

abstract:
  We study entanglement entropy in gravity theory with quantum effects. A
simplest model is a two dimensional Einstein-Hilbert action . We use an
$n$-sheet manifold to obtain an area term of entanglement entropy by summing
over all background fields. A strongly coupled conformal field theory is
expected to describe perturbative quantum gravity theory. Thus, we also use two
dimensional conformal field theory to discuss a factorization of a Hilbert
space. We find that a coefficient of a universal term of the entanglement
entropy is independent of a choice of an entangling surface in two dimensional
conformal field theory for one interval and also argue the result possibly be
extended to multiple intervals. Finally, we discuss that translational
invariance possibly be a necessary condition in a quantum gravity theory by
ruing out a volume law of entanglement entropy.


title: Linear and nonlinear stability of periodic orbits in annular billiards

abstract:
  An annular billiard is a dynamical system in which a particle moves freely in
a disk except for elastic collisions with the boundary, and also a circular
scatterer in the interior of the disk. We investigate stability properties of
some periodic orbits in annular billiards in which the scatterer is touching or
close to the boundary. We analytically show that there exist linearly stable
periodic orbits of arbitrary period for scatterers with decreasing radii that
are located near the boundary of the disk. As the position of the scatterer
moves away from a symmetry line of a periodic orbit, the stability of periodic
orbits changes from elliptic to hyperbolic, corresponding to a saddle-center
bifurcation. When the scatterer is tangent to the boundary, the periodic orbit
is parabolic. We prove that slightly changing the reflection angle of the orbit
in the tangential situation leads to the existence of KAM islands. Thus we show
that there exists a decreasing to zero sequence of open intervals of scatterer
radii, along which the billiard table is not ergodic.


title:
On the double-affine Bruhat order: the $\epsilon=1$ conjecture and
  classification of covers in ADE type

abstract:
  For any Kac-Moody group $\mathbf{G}$, we prove that the Bruhat order on the
semidirect product of the Weyl group and the Tits cone for $\mathbf{G}$ is
strictly compatible with a $\mathbb{Z}$-valued length function. We conjecture
in general and prove for $\mathbf{G}$ of affine ADE type that the Bruhat order
is graded by this length function. We also formulate and discuss conjectures
relating the length function to intersections of "double-affine Schubert
varieties."


title: Subsystems and time in quantum mechanics

abstract:
  This paper investigates the relationship between subsystems and time in a
closed nonrelativistic system of interacting bosons and fermions. It is
possible to write any state vector in such a system as an unentangled tensor
product of subsystem vectors, and to do so in infinitely many ways. This
requires the superposition of different numbers of particles, but the theory
can describe in full the equivalence relation that leads to a particle-number
superselection rule in conventionally defined subsystems. Time is defined as a
functional of subsystem changes, thus eliminating the need for any reference to
an external time variable. The dynamics of the unentangled subsystem
decomposition is derived from a variational principle of dynamical stability,
which requires the decomposition to change as little as possible in any given
infinitesimal time interval, subject to the constraint that the state of the
total system satisfy the Schroedinger equation. The resulting subsystem
dynamics is deterministic. This determinism is regarded as a conceptual tool
that observers can use to make inferences about the outside world, not as a law
of nature. The experiences of each observer define some properties of that
observer's subsystem during an infinitesimal interval of time (i.e., the
present moment); everything else must be inferred from this information. The
overall structure of the theory has some features in common with quantum
Bayesianism, the Everett interpretation, and dynamical reduction models, but it
differs significantly from all of these. The theory of information described
here is largely qualitative, as the most important equations have not yet been
solved. The quantitative level of agreement between theory and experiment thus
remains an open question.


title: A vanishing theorem for co-Higgs bundles on the moduli space of bundles

abstract:
  We consider smooth moduli spaces of semistable vector bundles of fixed rank
and determinant on a compact Riemann surface $X$ of genus at least $3$. The
choice of a Poincar\'e bundle for such a moduli space $M$ induces an
isomorphism between $X$ and a component of the moduli space of semistable
sheaves over $M$. We prove that $h^0(M, \text{End}({\mathcal E})\otimes TM)= 1$
for a vector bundle $\mathcal E$ on $M$ coming from this component.
Furthermore, there are no nonzero integrable co-Higgs fields on $\mathcal E$.


title:
Supermassive Black Hole Binary Environments: Effects on the Scaling Laws
  and Time to Detection for the Stochastic Background

abstract:
  One of the primary gravitational wave (GW) sources for pulsar timing arrays
(PTAs) is the stochastic background formed by supermassive black holes binaries
(SMBHBs). In this paper, we investigate how the environments of SMBHBs will
effect the sensitivity of PTAs by deriving scaling laws for the signal-to-noise
ratio (SNR) of the optimal cross-correlation statistic. The presence of gas and
stars around SMBHBs will accelerate the merger at large distances, depleting
the GW stochastic background at low frequencies. We show that environmental
interactions may delay detection by a few years or more, depending on the PTA
configuration and the frequency at which the dynamical evolution transitions
from being dominated by environmental effects to GW-dominated.


title:
Towards Energy-Efficient Communication Management in the Distributed
  Control of Networked Cyber-Physical Systems

abstract:
  In this paper, we study the distributed control of networked cyber-physical
systems when a much more energy-efficient distributed communication management
strategy is proposed to solve the well-studied consensus problem. In contrast
to the existing potential-based network topology control method, the proposed
topology control method is based on the variation of communication ranges such
that each agent can control its ad hoc communication range. The proposed
network topology control technique can not only guarantee network connectivity
but also reduce the communication energy. We apply the new network topology
control technique, based on variable communication ranges, in a well-studied
consensus problem, where the communication range for each agent is designed
locally along with a new bounded control algorithm. Theoretical analysis is
then provided to show that the proposed network topology control technique can
guarantee consensus with bounded communication energy consumption. Finally,
simulation examples are provided to show the effectiveness of the proposed
energy-efficient distributed topology control technique.


title: Cartan Theorems for Stein manifolds over a discrete valuation base

abstract:
  In this paper we prove Cartan theorems A and B for Stein manifolds over
certain discrete valuation rings.