title:
A pure hydrodynamic instability in shear flows and its application to
  astrophysical accretion disks

abstract:
  We provide the possible resolution for the century old problem of
hydrodynamic shear flows, which are apparently stable in linear analysis but
shown to be turbulent in astrophysically observed data and experiments. This
mismatch is noticed in a variety of systems, from laboratory to astrophysical
flows. There are so many uncountable attempts made so far to resolve this
mismatch, beginning with the early work of Kelvin, Rayleigh, and Reynolds
towards the end of the nineteenth century. Here we show that the presence of
stochastic noise, whose inevitable presence should not be neglected in the
stability analysis of shear flows, leads to pure hydrodynamic linear
instability therein. This explains the origin of turbulence, which has been
observed/interpreted in astrophysical accretion disks, laboratory experiments
and direct numerical simulations. This is, to the best of our knowledge, the
first solution to the long standing problem of hydrodynamic instability of
Rayleigh stable flows.


title: Non-Fermi glasses: fractionalizing electrons at finite energy density

abstract:
  Non-Fermi liquids are metals that cannot be adiabatically deformed into free
fermion states. We argue for the existence of "non-Fermi glasses," which are
phases of interacting disordered fermions that are fully many-body localized,
yet cannot be deformed into an Anderson insulator without an eigenstate phase
transition. We explore the properties of such non-Fermi glasses, focusing on a
specific solvable example. At high temperature, non-Fermi glasses have
qualitatively similar spectral features to Anderson insulators. We identify a
diagnostic, based on ratios of correlation functions, that sharply
distinguishes between the two phases even at infinite temperature. We argue
that our results and diagnostic should generically apply to the
high-temperature behavior of the many-body localized descendants of
fractionalized phases.


title: Chiral Magnetic Effect Task Force Report

abstract:
  In this report, we briefly examine the current status of the study of the
chiral magnetic effect including theory and experimental progress. We recommend
future strategies for resolving uncertainties in interpretation including
recommendations for theoretical work, recommendations for measurements based on
data collected in the past five years, and recommendations for beam use in the
coming years of RHIC. We have specifically investigated the case for colliding
nuclear isobars (nuclei with the same mass but different charge) and find the
case compelling. We recommend that a program of nuclear isobar collisions to
isolate the chiral magnetic effect from background sources be placed as a high
priority item in the strategy for completing the RHIC mission.


title:
NICIL: A stand alone library to self-consistently calculate non-ideal
  magnetohydrodynamic coefficients in molecular cloud cores

abstract:
  In this paper, we introduce Nicil: Non-Ideal magnetohydrodynamics
Coefficients and Ionisation Library. Nicil is a stand-alone Fortran90 module
that calculates the ionisation values and the coefficients of the non-ideal
magnetohydrodynamics terms of Ohmic resistivity, the Hall effect, and ambipolar
diffusion. The module is fully parameterised such that the user can decide
which processes to include and decide upon the values of the free parameters,
making this a versatile and customisable code. The module includes both cosmic
ray and thermal ionisation; the former includes two ion species and three
species of dust grains (positively charged, negatively charged and neutral),
and the latter includes five elements which can be doubly ionised. We
demonstrate tests of the module, and then describe how to implement it into an
existing numerical code.


title:
Ferromagnetic Damping/Anti-damping in a Periodic 2D Helical surface; A
  Non-Equilibrium Keldysh Green Function Approach

abstract:
  In this paper, we investigate theoretically the spin-orbit torque as well as
the Gilbert damping for a two band model of a 2D helical surface state with a
Ferromagnetic (FM) exchange coupling. We decompose the density matrix into the
Fermi sea and Fermi surface components and obtain their contributions to the
electronic transport as well as the spin-orbit torque (SOT). Furthermore, we
obtain the expression for the Gilbert damping due to the surface state of a 3D
Topological Insulator (TI) and predicted its dependence on the direction of the
magnetization precession axis.


title:
Cancer treatment scheduling and dynamic heterogeneity in social dilemmas
  of tumour acidity and vasculature

abstract:
  Background: Tumours are diverse ecosystems with persistent heterogeneity in
various cancer hallmarks like self-sufficiency of growth factor production for
angiogenesis and reprogramming of energy-metabolism for aerobic glycolysis.
This heterogeneity has consequences for diagnosis, treatment, and disease
progression.
  Methods: We introduce the double goods game to study the dynamics of these
traits using evolutionary game theory. We model glycolytic acid production as a
public good for all tumour cells and oxygen from vascularization via VEGF
production as a club good benefiting non-glycolytic tumour cells. This results
in three viable phenotypic strategies: glycolytic, angiogenic, and aerobic
non-angiogenic.
  Results: We classify the dynamics into three qualitatively distinct regimes:
(1) fully glycolytic, (2) fully angiogenic, or (3) polyclonal in all three cell
types. The third regime allows for dynamic heterogeneity even with linear
goods, something that was not possible in prior public good models that
considered glycolysis or growth-factor production in isolation.
  Conclusion: The cyclic dynamics of the polyclonal regime stress the
importance of timing for anti-glycolysis treatments like lonidamine. The
existence of qualitatively different dynamic regimes highlights the order
effects of treatments. In particular, we consider the potential of vascular
renormalization as a neoadjuvant therapy before follow up with interventions
like buffer therapy.


title: A Study of Ro-vibrational OH Emission from Herbig Ae/Be Stars

abstract:
  We present a study of ro-vibrational OH and CO emission from 21 disks around
Herbig Ae/Be stars. We find that the OH and CO luminosities are proportional
over a wide range of stellar ultraviolet luminosities. The OH and CO line
profiles are also similar, indicating that they arise from roughly the same
radial region of the disk. The CO and OH emission are both correlated with the
far-ultraviolet luminosity of the stars, while the PAH luminosity is correlated
with the longer wavelength ultraviolet luminosity of the stars. Although disk
flaring affects the PAH luminosity, it is not a factor in the luminosity of the
OH and CO emission. These properties are consistent with models of
UV-irradiated disk atmospheres. We also find that the transition disks in our
sample, which have large optically thin inner regions, have lower OH and CO
luminosities than non-transition disk sources with similar ultraviolet
luminosities. This result, while tentative given the small sample size, is
consistent with the interpretation that transition disks lack a gaseous disk
close to the star.


title:
Intrinsic Electrical Transport and Performance Projections of Synthetic
  Monolayer MoS2 Devices

abstract:
  We demonstrate monolayer MoS2 grown by chemical vapor deposition (CVD) with
transport properties comparable to those of the best exfoliated devices over a
wide range of carrier densities (up to ~10^13 1/cm^2) and temperatures (80-500
K). Transfer length measurements reveal monolayer mobility of ~20 cm2/V/s on
SiO2 substrates at 300 K and practical carrier densities (>2x10^12 1/cm^2). We
also demonstrate the highest current density reported to date (~270 uA/um or 44
MA/cm^2) at 300 K for an 80 nm device from CVD-grown monolayer MoS2. Using
simulations, we discuss what improvements of monolayer MoS2 are still required
to meet technology roadmap requirements for low power (LP) and high performance
(HP) applications. Such results are an important step towards large-area
electronics based on monolayer semiconductors.


title:
High Current Density and Low Thermal Conductivity of Atomically Thin
  Semimetallic WTe2

abstract:
  Two-dimensional (2D) semimetals beyond graphene have been relatively
unexplored in the atomically-thin limit. Here we introduce a facile growth
mechanism for semimetallic WTe2 crystals, then fabricate few-layer test
structures while carefully avoiding degradation from exposure to air. Low-field
electrical measurements of 80 nm to 2 um long devices allow us to separate
intrinsic and contact resistance, revealing metallic response in the thinnest
encapsulated and stable WTe2 devices studied to date (3 to 20 layers thick).
High-field electrical measurements and electro-thermal modeling demonstrate
that ultra-thin WTe2 can carry remarkably high current density (approaching 50
MA/cm2, higher than most common interconnect metals) despite a very low thermal
conductivity (of the order ~3 W/m/K). These results suggest several pathways
for air-stable technological viability of this layered semimetal.


title: Lock-free atom garbage collection for multithreaded Prolog

abstract:
  The runtime system of dynamic languages such as Prolog or Lisp and their
derivatives contain a symbol table, in Prolog often called the atom table. A
simple dynamically resizing hash-table used to be an adequate way to implement
this table. As Prolog becomes fashionable for 24x7 server processes we need to
deal with atom garbage collection and concurrent access to the atom table.
Classical lock-based implementations to ensure consistency of the atom table
scale poorly and a stop-the-world approach to implement atom garbage collection
quickly becomes a bottle-neck, making Prolog unsuitable for soft real-time
applications. In this article we describe a novel implementation for the atom
table using lock-free techniques where the atom-table remains accessible even
during atom garbage collection. Relying only on CAS (Compare And Swap) and not
on external libraries, the implementation is straightforward and portable.
  Under consideration for acceptance in TPLP.


title: Barrett: out-of-core processing of MultiNest output

abstract:
  Barrett is a Python package for processing and visualising statistical
inferences made using the nested sampling algorithm MultiNest. The main
differential feature from competitors are full out-of-core processing allowing
barrett to handle arbitrarily large datasets. This is achieved by using the
HDF5 data format.


title: Character degrees of extensions of the Suzuki groups $^2B_2(q^2)$

abstract:
  Let $S$ be a Suzuki group $^2B_2(q^2)$, where $q^2=2^{2f+1}$, $f\geqslant 1$.
In this paper, we determine the degrees of the ordinary complex irreducible
characters of every group $G$ such that $S\leqslant G\leqslant \Aut(S)$.


title: Mass inversion in graphene by proximity to dichalcogenide monolayer

abstract:
  Proximity effects resulting from depositing a graphene layer on a TMD
substrate layer change the dynamics of the electronic states in graphene,
inducing spin orbit coupling (SOC) and staggered potential effects. An
effective Hamiltonian that describes different symmetry breaking terms in
graphene, while preserving time reversal invariance, shows that an inverted
mass band gap regime is possible. The competition of different perturbation
terms causes a transition from an inverted mass phase to a staggered gap in the
bilayer heterostructure, as seen in its phase diagram. A tight-binding
calculation of the bilayer validates the effective model parameters. A relative
gate voltage between the layers may produce such phase transition in
experimentally accessible systems. The phases are characterized in terms of
Berry curvature and valley Chern numbers, demonstrating that the system may
exhibit quantum spin Hall and valley Hall effects.


title: Spintronics of Organometal Trihalide Perovskites

abstract:
  The family of organometal trihalide perovskite (OTP), CH3NH3PbX3 (where X is
halogen) has recently revolutionized the photovoltaics field and shows promise
in a variety of optoelectronic applications. The characteristic spin properties
of charge and neutral excitations in OTPs are influenced by the large
spin-orbit coupling of the Pb atoms, which may lead to spin-based device
applications. Here we report the first studies of pure spin-current and
spin-aligned carrier injection in OTP spintronics devices using spin-pumping
and spin-injection, respectively. We measure a relatively large
inverse-spin-Hall effect using pulsed microwave excitation in OTP devices at
resonance with a ferromagnetic substrate, from which we derive room temperature
spin diffusion length, lambda_sd~9nm; and low-temperature giant
magnetoresistance in OTP-based spin-valves from which we estimate
lambda_sd~85nm.


title: Geometry of entanglement in the Bloch sphere

abstract:
  Entanglement is an important concept in quantum information, quantum
communication, and quantum computing. We provide a geometrical analysis of
entanglement and separability for all the rank-2 quantum mixed states: complete
analysis for the bipartite states, and partial analysis for the multipartite
states. For each rank-2 mixed state, we define its unique Bloch sphere, that is
spanned by the eigenstates of its density matrix. We characterize those Bloch
spheres into exactly five classes of entanglement and separability, give
examples for each class, and prove that those are the only classes.


title:
Measurement of the in-plane thermal conductivity by steady-state
  infrared thermography

abstract:
  We demonstrate a simple and quick method for the measurement of the in-plane
thermal conductance of thin films via steady-state IR thermography. The films
are suspended above a hole in an opaque substrate and heated by a homogeneous
visible light source. The temperature distribution of the thin films is
captured via infrared microscopy and fitted to the analytical expression
obtained for the specific hole geometry in order to obtain the in-plane thermal
conductivity. For thin films of poly(3,4-ethylenedioxythiophene):polystyrene
sulfonate post-treated with ethylene glycol and of polyimide we find
conductivities of 1.0 W/mK and 0.4 W/mK at room temperature, respectively.
These results are in very good agreement with literature values, validating the
method developed.


title: ALMA Observations of Orion Source I at 350 and 660 GHz

abstract:
  Orion Source I (`SrcI') is the protostar at the center of the Kleinmann-Low
Nebula. ALMA observations of SrcI with 0.2" angular resolution were made at 350
and 660 GHz to search for the H26alpha and H21alpha hydrogen recombination
lines and to measure the continuum flux densities. The recombination lines were
not detected, ruling out the possibility that SrcI is a hypercompact HII
region. The deconvolved size of the continuum source is approximately 0.23 x
0.07" (100 x 30 AU); it is interpreted as a disk viewed almost edge-on.
Optically thick thermal emission from ~500 K dust is the most plausible source
of the continuum, even at frequencies as low as 43 GHz; the disk mass is most
likely in the range 0.02 to 0.2 Mo. A rich spectrum of molecular lines is
detected, mostly from sulfur- and silicon-rich molecules like SO, SO2, and SiS,
but also including vibrationally excited CO and several unidentified
transitions. Lines with upper energy levels E_U > 500 K appear in emission and
are symmetric about the source's LSR velocity of 5 km/sec, while lines with E_U
< 500 K appear as blueshifted absorption features against the continuum,
indicating that they originate in outflowing gas. The emission lines exhibit a
velocity gradient along the major axis of the disk that is consistent with
rotation around a 5-7 Mo central object. The relatively low mass of SrcI and
the existence of a 100 AU disk around it are difficult to reconcile with the
model in which SrcI and the nearby Becklin-Neugebauer Object were ejected from
a multiple system 500 years ago.


title: A tale of two Liouville closures

abstract:
  An $H$-field is a type of ordered valued differential field with a natural
interaction between ordering, valuation, and derivation. The main examples are
Hardy fields and fields of transseries. Aschenbrenner and van den Dries proved
in~\cite{MZ} that every $H$-field $K$ has either exactly one or exactly two
Liouville closures up to isomorphism over $K$, but the precise dividing line
between these two cases was unknown. We prove here that this dividing line is
determined by $\uplambda$-freeness, a property of $H$-fields that prevents
certain deviant behavior. In particular, we show that under certain types of
extensions related to adjoining integrals and exponential integrals, the
property of $\uplambda$-freeness is preserved. In the proofs we introduce a new
technique for studying $H$-fields, the \emph{yardstick argument} which involves
the rate of growth of pseudoconvergence.


title: Cooling mechanical oscillators by coherent control

abstract:
  In optomechanics, electromagnetic fields are harnessed to control a single
mode of a mechanically compliant system, while other mechanical degrees of
freedom remain unaffected due to the modes' mutual orthogonality and high
quality factor. Extension of the optical control beyond the directly addressed
mode would require a controlled coupling between mechanical modes. Here, we
introduce an optically controlled coupling between two oscillation modes of an
optically levitated nanoparticle. We sympathetically cool one oscillation mode
by coupling it coherently to the second mode, which is feedback cooled.
Furthermore, we demonstrate coherent energy transfer between mechanical modes
and discuss its application for ground-state cooling.


title:
Circular and Linear Photogalvanic Effects in Type-II GaSb/InAs Quantum
  Well Structures in the Inverted Regime

abstract:
  We report on the observation of photogalvanic effects induced by terahertz
radiation in type-II GaSb/InAs quantum wells with inverted band order.
Photocurrents are excited at oblique incidence of radiation and consists of
several contributions varying differently with the change of the radiation
polarization state; the one driven by the helicity and the other one driven by
the linearly polarization of radiation are of comparable magnitudes.
Experimental and theoretical analyses reveal that the photocurrent is dominated
by the circular and linear photogalvanic effects in a system with a dominant
structure inversion asymmetry. A microscopic theory developed in the framework
of the Boltzmann equation of motion considers both photogalvanic effects and
describes well all the experimental findings.


title: A solar twin in the eclipsing binary LL Aqr

abstract:
  In the course of a project to study eclipsing binary stars in vinicity of the
Sun, we found that the cooler component of LL Aqr is a solar twin candidate.
This is the first known star with properties of a solar twin existing in a
non-interacting eclipsing binary, offering an excellent opportunity to fully
characterise its physical properties with very high precision. We used
extensive multi-band, archival photometry and the Super-WASP project and
high-resolution spectroscopy obtained from the HARPS and CORALIE spectrographs.
The spectra of both components were decomposed and a detailed LTE abundance
analysis was performed. The light and radial velocity curves were simultanously
analysed with the Wilson-Devinney code. The resulting highly precise stellar
parameters were used for a detailed comparison with PARSEC, MESA, and GARSTEC
stellar evolution models. LL Aqr consists of two main-sequence stars (F9 V + G3
V) with masses of M1 = 1.1949$\pm$0.0007 and M2=1.0337$\pm$0.0007 $M_\odot$,
radii R1 = 1.321$\pm$0.006 and R2 = 1.002$\pm$0.005 $R_\odot$, temperatures
T1=6080$\pm$45 K and T2=5703$\pm$50 K and solar chemical composition
[M/H]=0.02$\pm$0.05 dex. The absolute dimensions, radiative and photometric
properties, and atmospheric abundances of the secondary are all fully
consistent with being a solar twin. Both stars are cooler by about 3.5 $\sigma$
or less metal abundant by 5$\sigma$ than predicted by standard sets of stellar
evolution models. When advanced modelling was performed, we found that full
agreement with observations can only be obtained for values of the mixing
length and envelope overshooting parameters that are hard to accept. The most
reasonable and physically justified model fits found with MESA and GARSTEC
codes still have discrepancies with observations but only at the level of
1$\sigma$.


title: An elementary approach to electromagnetic momentum in matter

abstract:
  We present an elementary discussion of the momentum transferred to a
conducting sheet by an electromagnetic wave propagating in a polarizable
medium. We show that conservation of momentum is consistent with Minkowski's
expression for the momentum density.


title: Unruh-DeWitt detector's response to fermions in flat spacetimes

abstract:
  We examine an Unruh-DeWitt particle detector that is coupled linearly to the
scalar density of a massless Dirac field in Minkowski spacetimes of dimension
$d\ge2$ and on the static Minkowski cylinder in spacetime dimension two,
allowing the detector's motion to remain arbitrary and working to leading order
in perturbation theory. In $d$-dimensional Minkowski, with the field in the
usual Fock vacuum, we show that the detector's response is identical to that of
a detector coupled linearly to a massless scalar field in $2d$-dimensional
Minkowski. In the special case of uniform linear acceleration, the detector's
response hence exhibits the Unruh effect with a Planckian factor in both even
and odd dimensions, in contrast to the Rindler power spectrum of the Dirac
field, which has a Planckian factor for odd $d$ but a Fermi-Dirac factor for
even~$d$. On the two-dimensional cylinder, we set the oscillator modes in the
usual Fock vacuum but allow an arbitrary state for the zero mode of the
periodic spinor. We show that the detector's response distinguishes the
periodic and antiperiodic spin structures, and the zero mode of the periodic
spinor contributes to the response by a state-dependent but well defined
amount. Explicit analytic and numerical results on the cylinder are obtained
for inertial and uniformly accelerated trajectories, recovering the $d=2$
Minkowski results in the limit of large circumference. The detector's response
has no infrared ambiguity for $d=2$, neither in Minkowski nor on the cylinder.


title: Rosenbluth separation of the $\pi^0$ electroproduction cross section

abstract:
  We present deeply virtual $\pi^0$ electroproduction cross-section
measurements at $x_B$=0.36 and three different $Q^2$--values ranging from 1.5
to 2 GeV$^2$, obtained from experiment E07-007 that ran in the Hall A at
Jefferson Lab. The Rosenbluth technique was used to separate the longitudinal
and transverse responses. Results demonstrate that the cross section is
dominated by its transverse component, and thus is far from the asymptotic
limit predicted by perturbative Quantum Chromodynamics. An indication of a
non-zero longitudinal contribution is provided by the interference term
$\sigma_{LT}$ also measured. Results are compared with several models based on
the leading twist approach of Generalized Parton Distributions (GPDs). In
particular, a fair agreement is obtained with models where the scattering
amplitude is described by a convolution of chiral-odd (transversity) GPDs of
the nucleon with the twist-3 pion distribution amplitude. Therefore, neutral
pion electroproduction may offer the exciting possibility of accessing
transversity GPDs through experiment.


title: What can Space Resources do for Astronomy and Planetary Science?

abstract:
  The rapid cost growth of flagship space missions has created a crisis for
astronomy and planetary science. We have hit the funding wall. For the past 3
decades scientists have not had to think much about how space technology would
change within their planning horizon. However, this time around enormous
improvements in space infrastructure capabilities and, especially, costs are
likely on the 20-year gestation periods for large space telescopes. Commercial
space will lower launch and spacecraft costs substantially, enable
cost-effective on-orbit servicing, cheap lunar landers and interplanetary
cubesats by the early 2020s. A doubling of flagship launch rates is not
implausible. On a longer timescale it will enable large structures to be
assembled and constructed in space. These developments will change how we plan
and design missions.


title: Using Gravitational Waves to put limits on Primordial Magnetic Fields

abstract:
  We describe a technique for using simulated tensor perturbations in order to
place upper limits on the intensity of magnetic fields in the early universe.
As an example, we apply this technique to the beginning of primordial
nucleosynthesis. We determined that any magnetic seed fields that existed
before that time were still in the process of being amplified. In the future,
we plan to apply this technique to a wider range of initial magnetic fields and
cosmological epochs.


title:
Intermediate Palomar Transient Factory: Realtime Image Subtraction
  Pipeline

abstract:
  A fast-turnaround pipeline for realtime data reduction plays an essential
role in discovering and permitting follow-up observations to young supernovae
and fast-evolving transients in modern time-domain surveys. In this paper, we
present the realtime image subtraction pipeline in the intermediate Palomar
Transient Factory. By using high-performance computing, efficient database, and
machine learning algorithms, this pipeline manages to reliably deliver
transient candidates within ten minutes of images being taken. Our experience
in using high performance computing resources to process big data in astronomy
serves as a trailblazer to dealing with data from large-scale time-domain
facilities in near future.


title: A Magnetar-like Outburst from a High-B Radio Pulsar

abstract:
  Radio pulsars are believed to have their emission powered by the loss of
rotational kinetic energy. By contrast, magnetars show intense X-ray and
gamma-ray radiation whose luminosity greatly exceeds that due to spin-down and
is believed to be powered by intense internal magnetic fields. A basic
prediction of this picture is that radio pulsars of high magnetic field should
show magnetar-like emission. Here we report on a magnetar-like X-ray outburst
from the radio pulsar PSR J1119-6127, heralded by two short bright X-ray bursts
on 2016 July 27 and 28 (Kennea et al. 2016; Younes et al. 2016). Using
Target-of-Opportunity data from the Swift X-ray Telescope and NuSTAR, we show
that this pulsar's flux has brightened by a factor of > 160 in the 0.5-10 keV
band, and its previously soft X-ray spectrum has undergone a strong hardening,
with strong pulsations appearing for the first time above 2.5 keV, with
phase-averaged emission detectable up to 25 keV. By comparing Swift-XRT and
NuSTAR timing data with a pre-outburst ephemeris derived from Fermi Large Area
Telescope data, we find that the source has contemporaneously undergone a large
spin-up glitch of amplitude df/f = 5.74(8) E-6. The collection of phenomena
observed thus far in this outburst strongly mirrors those in most magnetar
outbursts and provides an unambiguous connection between the radio pulsar and
magnetar populations.


title:
Fast Mixing Markov Chains for Strongly Rayleigh Measures, DPPs, and
  Constrained Sampling

abstract:
  We study probability measures induced by set functions with constraints. Such
measures arise in a variety of real-world settings, where prior knowledge,
resource limitations, or other pragmatic considerations impose constraints. We
consider the task of rapidly sampling from such constrained measures, and
develop fast Markov chain samplers for them. Our first main result is for MCMC
sampling from Strongly Rayleigh (SR) measures, for which we present sharp
polynomial bounds on the mixing time. As a corollary, this result yields a fast
mixing sampler for Determinantal Point Processes (DPPs), yielding (to our
knowledge) the first provably fast MCMC sampler for DPPs since their inception
over four decades ago. Beyond SR measures, we develop MCMC samplers for
probabilistic models with hard constraints and identify sufficient conditions
under which their chains mix rapidly. We illustrate our claims by empirically
verifying the dependence of mixing times on the key factors governing our
theoretical bounds.


title:
Co-design of a particle-in-cell plasma simulation code for Intel Xeon
  Phi: a first look at Knights Landing

abstract:
  Three dimensional particle-in-cell laser-plasma simulation is an important
area of computational physics. Solving state-of-the-art problems requires
large-scale simulation on a supercomputer using specialized codes. A growing
demand in computational resources inspires research in improving efficiency and
co-design for supercomputers based on many-core architectures. This paper
presents first performance results of the particle-in-cell plasma simulation
code PICADOR on the recently introduced Knights Landing generation of Intel
Xeon Phi. A straightforward rebuilding of the code yields a 2.43 x speedup
compared to the previous Knights Corner generation. Further code optimization
results in an additional 1.89 x speedup. The optimization performed is
beneficial not only for Knights Landing, but also for high-end CPUs and Knights
Corner. The optimized version achieves 100 GFLOPS double precision performance
on a Knights Landing device with the speedups of 2.35 x compared to a 14-core
Haswell CPU and 3.47 x compared to a 61-core Knights Corner Xeon Phi.


title: A new type of factorial series expansions and applications

abstract:
  We construct a new type of convergent asymptotic representations, dyadic
factorial expansions. Their convergence is geometric and the region of
convergence can include Stokes rays, and often extends down to 0^+. For special
functions such as Bessel, Airy, Ei, Erfc, Gamma and others, this region is C
without an arbitrarily chosen ray effectively providing uniform convergent
asymptotic expansions for special functions.
  We prove that relatively general functions, Ecalle resurgent ones possess
convergent dyadic factorial expansions. We show that dyadic expansions are
numerically efficient representations.
  The expansions translate into representations of the resolvent of
self-adjoint operators in series in terms of the associated unitary evolution
operator evaluated at some prescribed points (alternatively, in terms of the
generated semigroup for positive operators).


title: Certifying the absence of quantum nonlocality

abstract:
  Quantum nonlocality is an inherently non-classical feature of quantum
mechanics and manifests itself through violation of Bell inequalities for
nonlocal games. We show that in a fairly general setting, a simple extension of
a nonlocal game can certify instead the absence of quantum nonlocality. Through
contraposition, our result implies that a super-classical performance for such
a game ensures that a player's output is unpredictable to the other player.
Previously such output unpredictability was known with respect to a third
party.


title: A likely inverse-Compton emission from the Type IIb SN 2013df

abstract:
  The inverse-Compton X-ray emission model for supernovae has been well
established to explain the X-ray properties of many supernovae for over 30
years. However, no observational case has yet been found to connect the X-rays
with the optical lights as they should be. Here, we report the discovery of a
hard X-ray source that is associated with a Type II-b supernova. Simultaneous
emission enhancements have been found in both the X-ray and optical light
curves twenty days after the supernova explosion. While the enhanced X-rays are
likely dominated by inverse-Compton scatterings of the supernova's lights from
the Type II-b secondary peak, we propose a scenario of a high-speed supernova
ejecta colliding with a low-density pre-supernova stellar wind that produces an
optically thin and high-temperature electron gas for the Comptonization. The
inferred stellar wind mass-loss rate is consistent with that of the supernova
progenitor candidate as a yellow supergiant detected by the Hubble Space
Telescope, providing an independent proof for the progenitor. This is also new
evidence of the inverse-Compton emission during the early phase of a supernova.


title: Summarizing Large Query Logs in Ettu

abstract:
  Database access logs are large, unwieldy, and hard for humans to inspect and
summarize. In spite of this, they remain the canonical go-to resource for tasks
ranging from performance tuning to security auditing. In this paper, we address
the challenge of compactly encoding large sequences of SQL queries for
presentation to a human user. Our approach is based on the Weisfeiler-Lehman
(WL) approximate graph isomorphism algorithm, which identifies salient features
of a graph or in our case of an abstract syntax tree. Our generalization of WL
allows us to define a distance metric for SQL queries, which in turn permits
automated clustering of queries. We also present two techniques for visualizing
query clusters, and an algorithm that allows these visualizations to be
constructed at interactive speeds. Finally, we evaluate our algorithms in the
context of a motivating example: insider threat detection at a large US bank.
We show experimentally on real world query logs that (a) our distance metric
captures a meaningful notion of similarity, and (b) the log summarization
process is scalable and performant.


title: Bohr topology and difference sets for some abelian groups

abstract:
  For a fixed prime $p$, $\mathbb F_{p}$ denotes the field with $p$ elements,
and $\mathbb F_{p}^{\omega}$ denotes the countable direct sum
$\bigoplus_{n=1}^{\infty} \mathbb F_{p}$. Viewing $\mathbb F_{p}^{\omega}$ as a
countable abelian group, we construct a set $A\subseteq \mathbb F_{p}^{\omega}$
having positive upper Banach density while the difference set
$A-A:=\{a-b:a,b\in A\}$ does not contain a Bohr neighborhood of any $c\in
\mathbb F_{p}^{\omega}$. For $p=2$ we obtain a stronger conclusion: $A-A$ does
not contain a set of the form $g+(B-B)$, where $B$ is piecewise syndetic. This
construction answers negatively a variant of the following question asked by
several authors: if $A\subseteq \mathbb Z$ has positive upper Banach density,
must $A-A$ contain a Bohr neighborhood of some $n\in \mathbb Z$?
  We also construct sets $S, A\subseteq \mathbb F_{p}^{\omega}$ such that $S$
is dense in the Bohr topology of $\mathbb F_{p}^{\omega}$, $A$ has positive
upper Banach density, and $A+S$ is not piecewise Bohr. For $p=2$ we show that
every translate of $S$ is a set of topological recurrence and $A+S$ is not
piecewise syndetic. These constructions answer a variant of a question asked by
the author.


title: Radiation from an off-centred rotating dipole in vacuum

abstract:
  When a neutron star forms, after the collapse of its progenitor, a strong
magnetic field survives in its interior. This magnetic topology is usually
assumed to be well approximated by a dipole located right at the centre of the
star. However, there is no particular reason why this dipole should be attached
to this very special point. A slight shift from the stellar centre could have
strong implications for the surrounding electromagnetic field configuration
leading to clear observational signatures. We study the effect of the most
general off-centred dipole anchored in the neutron star interior. Exact
analytical solutions are given in vacuum outside the star to any order of
accuracy in the small parameter $\epsilon = d/R$, where $d$ is the displacement
of the dipole from the stellar centre and $R$ the neutron star radius. As a
simple diagnostic of this decentred dipole, the spin-down luminosity and the
torque exerted on its crust are computed to the lowest leading order
in~$\epsilon$. Results are compared to earlier works and a discussion on
repercussions on pulsar braking index and multi-wavelength light curves is
proposed.


title: One-dimensional random interlacements

abstract:
  We base ourselves on the construction of the two-dimensional random
interlacements [12] to define the one-dimensional version of the process. For
this constructions we consider simple random walks conditioned on never hitting
the origin, which makes them transient. We also compare this process to the
conditional random walk on the ring graph. Our results are the convergence of
the vacant set on the ring graph to the vacant set of one-dimensional random
interlacements, a central limit theorem for the interlacements' local time for
sites far from the origin and the convergence in law of the local times of the
conditional walk on the ring graph to the interlacements' local times.


title:
Automated X-ray Image Analysis for Cargo Security: Critical Review and
  Future Promise

abstract:
  We review the relatively immature field of automated image analysis for X-ray
cargo imagery. There is increasing demand for automated analysis methods that
can assist in the inspection and selection of containers, due to the
ever-growing volumes of traded cargo and the increasing concerns that customs-
and security-related threats are being smuggled across borders by organised
crime and terrorist networks. We split the field into the classical pipeline of
image preprocessing and image understanding. Preprocessing includes: image
manipulation; quality improvement; Threat Image Projection (TIP); and material
discrimination and segmentation. Image understanding includes: Automated Threat
Detection (ATD); and Automated Contents Verification (ACV). We identify several
gaps in the literature that need to be addressed and propose ideas for future
research. Where the current literature is sparse we borrow from the
single-view, multi-view, and CT X-ray baggage domains, which have some
characteristics in common with X-ray cargo.


abstract:
  This volume contains the Proceedings of the 2016 Workshop on Semantic Spaces
at the Intersection of NLP, Physics and Cognitive Science (SLPCS 2016), which
was held on the 11th of June at the University of Strathclyde, Glasgow, and was
co-located with Quantum Physics and Logic (QPL 2016). Exploiting the common
ground provided by the concept of a vector space, the workshop brought together
researchers working at the intersection of Natural Language Processing (NLP),
cognitive science, and physics, offering them an appropriate forum for
presenting their uniquely motivated work and ideas. The interplay between these
three disciplines inspired theoretically motivated approaches to the
understanding of how word meanings interact with each other in sentences and
discourse, how diagrammatic reasoning depicts and simplifies this interaction,
how language models are determined by input from the world, and how word and
sentence meanings interact logically. This first edition of the workshop
consisted of three invited talks from distinguished speakers (Hans Briegel,
Peter G\"ardenfors, Dominic Widdows) and eight presentations of selected
contributed papers. Each submission was refereed by at least three members of
the Programme Committee, who delivered detailed and insightful comments and
suggestions.


title: The Entity Registry System. From concept to deployment

abstract:
  The entity registry system (ERS) is a decentralized entity registry that can
be used to replace the Web as a platform for publishing linked data when the
latter is not available. In developing countries, where off-line is the default
mode of operation, centralized linked data solutions fail to address the needs
of the communities. Although the features are mostly completed, the system is
not yet ready for deployment. This project aims to provide extensive tests and
scalability investigations that would make it ready for a real scenario.


title: Collective modes of trapped spinor Bose condensates

abstract:
  We study the richer structures of quasi-one-dimensional Bogoliubov-de Genes
collective excitations of F = 1 spinor Bose-Einstein condensate in a harmonic
trap potential loaded in an optical lattice. Employing a perturbative method we
report general analytical expressions for the confined collective polar and
ferromagnetic Goldstone modes. In both cases the excited eigenfrequencies are
given as function of the 1D effective coupling constants, trap frequency and
optical lattice parameters. It is shown that the main contribution of the
optical lattice laser intensity is to shift the confined phonon frequencies.
Moreover, for high intensities, the excitation spectrum becomes independent of
the self-interaction parameters. We reveal some features of the evolution for
the Goldstone modes as well as the condensate densities from the ferromagnetic
to the polar phases.


title:
Analysis of M2/M2/1/R,N Queuing Model for Multimedia over 3.5G Wireless
  Network Downlink

abstract:
  Analysis of an M2/M2/1/R, N queuing model for the multimedia transmission
over HSDPA/3.5G downlink is presented. The queue models the downlink buffer
with source multimedia traffic streams comprising two classes of flows:
realtime and non real-time. Time priority is accorded to the real-time flows
while the non real-time flows are given buffer space priority. An analytic
evaluation of the impact of varying the buffer partition threshold on the QoS
performance of both classes of customers is undertaken. The results are
validated with a discrete event simulation model developed in C language.
Finally, a cost function for the joint optimization of the traffic QoS
parameters is derived.


title:
Towards a Splitter Theorem for Internally $4$-connected Binary Matroids
  VI

abstract:
  Let $M$ be a $3$-connected binary matroid; $M$ is called internally
$4$-connected if one side of every $3$-separation is a triangle or a triad, and
$M$ is $(4,4,S)$-connected if one side of every $3$-separation is a triangle, a
triad, or a $4$-element fan. Assume $M$ is internally $4$-connected and that
neither $M$ nor its dual is a cubic M\"{o}bius or planar ladder or a certain
coextension thereof. Let $N$ be an internally $4$-connected proper minor of
$M$. Our aim is to show that $M$ has a proper internally $4$-connected minor
with an $N$-minor that can be obtained from $M$ either by removing at most four
elements, or by removing elements in an easily described way from a special
substructure of $M$. When this aim cannot be met, the earlier papers in this
series showed that, up to duality, $M$ has a good bowtie, that is, a pair,
$\{x_1,x_2,x_3\}$ and $\{x_4,x_5,x_6\}$, of disjoint triangles and a cocircuit,
$\{x_2,x_3,x_4,x_5\}$, where $M\backslash x_3$ has an $N$-minor and is
$(4,4,S)$-connected. We also showed that, when $M$ has a good bowtie, either
$M\backslash x_3,x_6$ has an $N$-minor; or $M\backslash x_3/x_2$ has an
$N$-minor and is $(4,4,S)$-connected. In this paper, we show that, when
$M\backslash x_3,x_6$ has an $N$-minor but is not $(4,4,S)$-connected, $M$ has
an internally $4$-connected proper minor with an $N$-minor that can be obtained
from $M$ by removing at most three elements, or by removing elements in a
well-described way from one of several special substructures of $M$. This is a
significant step towards obtaining a splitter theorem for the class of
internally $4$-connected binary matroids.


title:
End-to-End QoS Improvement of HSDPA End-User Multi-flow Traffic Using
  RAN Buffer Management

abstract:
  High Speed Downlink Packet Access (HSDPA) was introduced to UMTS radio access
segment to provide higher capacity for new packet switched services. As a
result, packet switched sessions with multiple diverse traffic flows such as
concurrentvoice and data, or video and data being transmitted to the same user
are a likely commonplace cellular packet data scenario. In HSDPA, Radio Access
Network (RAN) buffer management schemes are essential to support the end-to-end
QoS of such sessions. Hence in this paper we present the end-to-end performance
study of a proposed RAN buffer management scheme for multi-flow sessions via
dynamic system-level HSDPA simulations. The scheme is an enhancement of a
Time-Space Priority (TSP)queuing strategy applied to the Node B MAC-hs buffer
allocated to an end user with concurrent real-time (RT) and non-real-time (NRT)
flows during a multi-flow session. The experimental multiflow scenario is a
packet voice call with concurrent TCP-based file download to the same user.
Results show that with the proposed enhancements to the TSP-based RAN buffer
management, end-to-end QoS performance gains accrue to the NRT flow without
compromising RT flow QoS of the same end user session.


title:
Incremental Real-Time Multibody VSLAM with Trajectory Optimization Using
  Stereo Camera

abstract:
  Real time outdoor navigation in highly dynamic environments is an crucial
problem. The recent literature on real time static SLAM don't scale up to
dynamic outdoor environments. Most of these methods assume moving objects as
outliers or discard the information provided by them. We propose an algorithm
to jointly infer the camera trajectory and the moving object trajectory
simultaneously. In this paper, we perform a sparse scene flow based motion
segmentation using a stereo camera. The segmented objects motion models are
used for accurate localization of the camera trajectory as well as the moving
objects. We exploit the relationship between moving objects for improving the
accuracy of the poses. We formulate the poses as a factor graph incorporating
all the constraints. We achieve exact incremental solution by solving a full
nonlinear optimization problem in real time. The evaluation is performed on the
challenging KITTI dataset with multiple moving cars.Our method outperforms the
previous baselines in outdoor navigation.


title: $m$-Modular Wythoff

abstract:
  We discuss a variant of Wythoff's Game, $m$-Modular Wythoff's Game, and
identify the winning and losing positions for this game.


title: One-Class Slab Support Vector Machine

abstract:
  This work introduces the one-class slab SVM (OCSSVM), a one-class classifier
that aims at improving the performance of the one-class SVM. The proposed
strategy reduces the false positive rate and increases the accuracy of
detecting instances from novel classes. To this end, it uses two parallel
hyperplanes to learn the normal region of the decision scores of the target
class. OCSSVM extends one-class SVM since it can scale and learn non-linear
decision functions via kernel methods. The experiments on two publicly
available datasets show that OCSSVM can consistently outperform the one-class
SVM and perform comparable to or better than other state-of-the-art one-class
classifiers.


title:
Towards a Splitter Theorem for Internally $4$-connected Binary Matroids
  VII

abstract:
  Let $M$ be a $3$-connected binary matroid; $M$ is internally $4$-connected if
one side of every $3$-separation is a triangle or a triad, and $M$ is
$(4,4,S)$-connected if one side of every $3$-separation is a triangle, a triad,
or a $4$-element fan. Assume $M$ is internally $4$-connected and that neither
$M$ nor its dual is a cubic M\"{o}bius or planar ladder or a certain
coextension thereof. Let $N$ be an internally $4$-connected proper minor of
$M$. Our aim is to show that $M$ has a proper internally $4$-connected minor
with an $N$-minor that can be obtained from $M$ either by removing at most four
elements, or by removing elements in an easily described way from a special
substructure of $M$. When this aim cannot be met, the earlier papers in this
series showed that, up to duality, $M$ has a good bowtie, that is, a pair,
$\{x_1,x_2,x_3\}$ and $\{x_4,x_5,x_6\}$, of disjoint triangles and a cocircuit,
$\{x_2,x_3,x_4,x_5\}$, where $M\backslash x_3$ has an $N$-minor and is \ffsc.
We also showed that, when $M$ has a good bowtie, either $M\backslash x_3,x_6$
has an $N$-minor and $M\backslash x_6$ is $(4,4,S)$-connected; or $M\backslash
x_3/x_2$ has an $N$-minor and is \ffsc. In this paper, we show that, when
$M\backslash x_3,x_6$ has no $N$-minor, $M$ has an internally $4$-connected
proper minor with an $N$-minor that can be obtained from $M$ by removing at
most three elements, or by removing elements in a well-described way from a
special substructure of $M$. This is the penultimate step towards obtaining a
splitter theorem for the class of internally $4$-connected binary matroids.


title:
Nonlinear Waves in Lattice Materials: Adaptively Augmented Directivity
  and Functionality Enhancement by Modal Mixing

abstract:
  The motive of this work is to understand the complex spatial characteristics
of finite-amplitude elastic wave propagation in periodic structures and
leverage the unique opportunities offered by nonlinearity to activate
complementary functionalities and design adaptive spatial wave manipulators.
The underlying assumption is that the magnitude of wave propagation is small
with respect to the length scale of the structure under consideration, albeit
large enough to elicit the effects of finite-deformation. We demonstrate that
the interplay of dispersion, nonlinearity and modal complexity involved in the
generation and propagation of higher harmonics gives rise to secondary wave
packets that feature multiple characteristics, one of which conforms to the
dispersion relation of the corresponding linear structure. This provides an
opportunity to engineer desired wave characteristics through a geometric and
topological design of the unit cell, and results in the ability to activate
complementary functionalities, typical of high frequency regimes, while
operating at low frequencies of excitation - an effect seldom observed in
linear periodic structures. The ability to design adaptive switches is
demonstrated here using lattice configurations whose response is characterized
by geometric and/or material nonlinearities.


title:
Study Of Si-Ge Interdiffusion With a High Phosphorus Doping
  Concentration

abstract:
  Si-Ge interdiffusion with a high phosphorus doping level was investigated by
both experiments and modeling. Ge/Si1-xGex/Ge multi-layer structures with
0.75<x_Ge<1 , a mid-10^18 to low-10^19 cm-3 P doping and a dislocation density
of 10^8 to 10^9 cm-2 range were studied. The P-doped sample shows an
accelerated Si-Ge interdiffusivity, which is 2-8 times of that of the undoped
sample. The doping dependence of the Si-Ge interdiffusion was modelled by a
Fermi-enhancement factor. The results show that Si-Ge interdiffusion
coefficient is proportional to n^2/n_i^2 for the conditions studied, which
indicates that the interdiffusion in high Ge fraction range with n-type doping
is dominated by V^(2-) defects. The Fermi-enhancement factor was shown to have
a relatively weak dependence on the temperature and the Ge fraction. The
results are relevant to structure and thermal processing condition design of
n-type doped Ge/Si and Ge/SiGe based devices such as Ge/Si lasers.


title:
Results from the 2014 November 15th multi-chord stellar occultation by
  the TNO (229762) 2007 UK$_{126}$

abstract:
  We present results derived from the first multi-chord stellar occultation by
the trans-Neptunian object (229762) 2007 UK$_{126}$, observed on 2014 November
15. The event was observed by the Research and Education Collaborative
Occultation Network (RECON) project and International Occultation Timing
Association (IOTA) collaborators throughout the United States. Use of two
different data analysis methods obtain a satisfactory fit to seven chords,
yelding an elliptical fit to the chords with an equatorial radius of
$R=338_{-10} ^{+15}$ km and equivalent radius of $R_{eq}=319_{-7} ^{+14}$ km. A
circular fit also gives a radius of $R=324_{-23} ^{+30}$ km. Assuming that the
object is a Maclaurin spheroid with indeterminate aspect angle, and using two
published absolute magnitudes for the body, we derive possible ranges for
geometric albedo between $p_{V}=0.159_{-0.013} ^{+0.007}$ and
$p_{R}=0.189_{-0.015}^{+0.009}$, and for the body oblateness between
$\epsilon=0.105_{-0.040} ^{+0.050}$ and $\epsilon=0.118_{-0.048} ^{+0.055}$.
For a nominal rotational period of 11.05 h, an upper limit for density of
$\rho=1740$ kg~m$^{-3}$ is estimated for the body.


title:
Meraculous2: fast accurate short-read assembly of large polymorphic
  genomes

abstract:
  We present Meraculous2, an update to the Meraculous short-read assembler that
includes (1) handling of allelic variation using "bubble" structures within the
de Bruijn graph, (2) improved gap closing, and (3) an improved scaffolding
algorithm that produces more complete assemblies without compromising
scaffolding accuracy. The speed and bandwidth efficiency of the new parallel
implementation have also been substantially improved, allowing the assembly of
a human genome to be accomplished in 24 hours on the JGI/NERSC Genepool system.
To highlight the features of Meraculous2 we present here the assembly of the
diploid human genome NA12878, and compare it with previously published
assemblies of the same data using other algorithms. The Meraculous2 assemblies
are shown to have better completeness, contiguity, and accuracy than other
published assemblies for these data. Practical considerations including
pre-assembly analyses of polymorphism and repetitiveness are described.


title:
Full measure reducibility and localization for Jacobi operators: a
  topological criterion

abstract:
  We establish a topological criterion for connection between reducibility to
constant rotations and dual localization, for the general family of analytic
quasiperiodic Jacobi operators. As a corollary, we obtain the sharp arithmetic
phase transition for the extended Harper's model in the positive Lyapunov
exponent region.


title:
Spinning, Precessing, Black Hole Binary Spacetime via Asymptotic
  Matching

abstract:
  We briefly discuss a method to construct a global, analytic, approximate
spacetime for precessing, spinning binary black holes. The spacetime
construction is broken into three parts: the inner zones are the spacetimes
close to each black hole, and are approximated by perturbed Kerr solutions; the
near zone is far from the two black holes, and described by the post-Newtonian
metric; and finally the wave (far) zone, where retardation effects need to be
taken into account, is well modeled by the post-Minkowskian metric. These
individual spacetimes are then stitched together using asymptotic matching
techniques to obtain a global solution that approximately satisfies the
Einstein field equations. Precession effects are introduced by rotating the
black hole spin direction according to the precessing equations of motion, in a
way that is consistent with the global spacetime construction.


title:
SU(3) Polyakov linear-sigma model: bulk and shear viscosity of QCD
  matter in finite magnetic field

abstract:
  Due to off-center relativistic motion of the charged spectators and the local
momentum-imbalance of the participants, a short-lived huge magnetic field is
likely generated, especially in relativistic heavy-ion collisions. In
determining the temperature dependence of bulk and shear viscosities of the QCD
matter in vanishing and finite magnetic field, we utilize mean field
approximation to the SU($3$) Polyakov linear-sigma model (PLSM). We compare
between the results from two different approaches; Green-Kubo correlation and
Boltzmann master equation with Chapman-Enskog expansion. We find that both
approaches have almost identical results, especially in the hadron phase. In
the temperature dependence of bulk and shear viscosities relative to thermal
entropy at the critical temperature, there is a rapid decrease in the chiral
phase-transition and in the critical temperature with increasing magnetic
field. As the magnetic field strength increases, a peak appears at the critical
temperature ($T_c$). This can be understood from the small drop on the thermal
entropy at $T_c$, which can be interpreted due to instability in the
hydrodynamic flow of the quark-gluon plasma and soft statistical hadronization.
It is obvious that, increasing magnetic field accelerates the transition from
hadron to QGP phases (inverse catalysis), i.e., taking place at lower
temperatures.


title:
Wavenumber-explicit analysis for the Helmholtz $h$-BEM: error estimates
  and iteration counts for the Dirichlet problem

abstract:
  We consider solving the exterior Dirichlet problem for the Helmholtz equation
with the $h$-version of the boundary element method (BEM) using the standard
second-kind combined-field integral equations. We prove a new, sharp bound on
how the number of GMRES iterations must grow with the wavenumber $k$ to have
the error in the iterative solution bounded independently of $k$ as
$k\rightarrow \infty$ when the boundary of the obstacle is analytic and has
strictly positive curvature. To our knowledge, this result is the first-ever
sharp bound on how the number of GMRES iterations depends on the wavenumber for
an integral equation used to solve a scattering problem. We also prove new
bounds on how $h$ must decrease with $k$ to maintain $k$-independent
quasi-optimality of the Galerkin solutions as $k \rightarrow \infty$ when the
obstacle is nontrapping.


title:
Fast and Lean Immutable Multi-Maps on the JVM based on Heterogeneous
  Hash-Array Mapped Tries

abstract:
  An immutable multi-map is a many-to-many thread-friendly map data structure
with expected fast insert and lookup operations. This data structure is used
for applications processing graphs or many-to-many relations as applied in
static analysis of object-oriented systems. When processing such big data sets
the memory overhead of the data structure encoding itself is a memory usage
bottleneck. Motivated by reuse and type-safety, libraries for Java, Scala and
Clojure typically implement immutable multi-maps by nesting sets as the values
with the keys of a trie map. Like this, based on our measurements the expected
byte overhead for a sparse multi-map per stored entry adds up to around 65B,
which renders it unfeasible to compute with effectively on the JVM.
  In this paper we propose a general framework for Hash-Array Mapped Tries on
the JVM which can store type-heterogeneous keys and values: a Heterogeneous
Hash-Array Mapped Trie (HHAMT). Among other applications, this allows for a
highly efficient multi-map encoding by (a) not reserving space for empty value
sets and (b) inlining the values of singleton sets while maintaining a (c)
type-safe API.
  We detail the necessary encoding and optimizations to mitigate the overhead
of storing and retrieving heterogeneous data in a hash-trie. Furthermore, we
evaluate HHAMT specifically for the application to multi-maps, comparing them
to state-of-the-art encodings of multi-maps in Java, Scala and Clojure. We
isolate key differences using microbenchmarks and validate the resulting
conclusions on a real world case in static analysis. The new encoding brings
the per key-value storage overhead down to 30B: a 2x improvement. With
additional inlining of primitive values it reaches a 4x improvement.


title:
The robustness of interdependent networks under the interplay between
  cascading failures and virus propagation

abstract:
  Cascading failures and epidemic dynamics, as two successful application
realms of network science, are usually investigated separately. How do they
affect each other is still one open, interesting problem. In this letter, we
couple both processes and put them into the framework of interdependent
networks, where each network only supports one dynamical process. Of particular
interest, they spontaneously form a feedback loop: virus propagation triggers
cascading failures of systems while cascading failures suppress virus
propagation. Especially, there exists crucial threshold of virus
transmissibility, above which the interdependent networks collapse completely.
In addition, the interdependent networks will be more vulnerable if the network
supporting virus propagation has denser connections; otherwise the
interdependent systems are robust against the change of connections in other
layer(s). This discovery differs from previous framework of cascading failure
in interdependent networks, where better robustness usually needs denser
connections. Finally, to protect interdependent networks we also propose the
control measures based on the identification capability. The larger this
capability, more robustness the interdependent networks will be.


title: Competing spreading processes and immunization in multiplex networks

abstract:
  Epidemic spreading on physical contact network will naturally introduce the
human awareness information diffusion on virtual contact network, and the
awareness diffusion will in turn depress the epidemic spreading, thus forming
the competing spreading processes of epidemic and awareness in a multiplex
networks. In this paper, we study the competing dynamics of epidemic and
awareness, both of which follow the SIR process, in a two-layer networks based
on microscopic Markov chain approach and numerical simulations. We find that
strong capacities of awareness diffusion and self-protection of individuals
could lead to a much higher epidemic threshold and a smaller outbreak size.
However, the self-awareness of individuals has no obvious effect on the
epidemic threshold and outbreak size. In addition, the immunization of the
physical contact network under the interplay between of epidemic and awareness
spreading is also investigated. The targeted immunization is found performs
much better than random immunization, and the awareness diffusion could reduce
the immunization threshold for both type of random and targeted immunization
significantly.


title: Empirical Evaluation of Real World Tournaments

abstract:
  Computational Social Choice (ComSoc) is a rapidly developing field at the
intersection of computer science, economics, social choice, and political
science. The study of tournaments is fundamental to ComSoc and many results
have been published about tournament solution sets and reasoning in
tournaments. Theoretical results in ComSoc tend to be worst case and tell us
little about performance in practice. To this end we detail some experiments on
tournaments using real wold data from soccer and tennis. We make three main
contributions to the understanding of tournaments using real world data from
English Premier League, the German Bundesliga, and the ATP World Tour: (1) we
find that the NP-hard question of finding a seeding for which a given team can
win a tournament is easily solvable in real world instances, (2) using detailed
and principled methodology from statistical physics we show that our real world
data obeys a log-normal distribution; and (3) leveraging our log-normal
distribution result and using robust statistical methods, we show that the
popular Condorcet Random (CR) tournament model does not generate realistic
tournament data.


title: Eulerian properties of hypergraphs

abstract:
  In this paper we study three substructures in hypergraphs that generalize the
notion of an Euler tour in a graph. A flag-traversing tour of a hypergraph
corresponds to an Euler tour of its incidence graph, hence complete
characterization of hypergraphs with an Euler tour follows from Euler's
Theorem. An Euler tour is a closed walk that traverses each edge of the
hypergraph exactly once; and an Euler family is a family of closed walks that
cannot be concatenated and that jointly traverse each edge of the hypergraph
exactly once. Lonc and Naroski have shown that the problem of existence of an
Euler tour is NP-complete even on a very restricted subclass of 3-uniform
hypergraphs, while we show that the problem of existence of an Euler family is
polynomial on the class of all hypergraphs.
  Furthermore, we examine the necessary conditions for a hypergraph to admit an
Euler family (Euler tour, respectively); we show that while these necessary
conditions are sufficient for connected graphs, they are not sufficient for
general hypergraphs. On the other hand, we exhibit a new class of hypergraphs
for which these necessary conditions are also sufficient, extending a result by
Lonc and Naroski. We give a partial characterization of hypergraphs with an
Euler family (Euler tour, respectively) in terms of the intersection graph of
the hypergraph, and a complete (but not easy to verify) characterization in
terms of the incidence graph. For hypergraphs with an Euler family, we give a
complete verifiable characterization using a theorem of Lov\'{a}sz, and then
show that every 3-uniform hypergraph without cut edges admits an Euler family.
Finally, we show that a hypergraph admits an Euler family if and only if it can
be decomposed into cycles, and exhibit a relationship between 2-factors in a
hypergraph and eulerian properties of its dual.


title:
Training Deep Networks for Facial Expression Recognition with
  Crowd-Sourced Label Distribution

abstract:
  Crowd sourcing has become a widely adopted scheme to collect ground truth
labels. However, it is a well-known problem that these labels can be very
noisy. In this paper, we demonstrate how to learn a deep convolutional neural
network (DCNN) from noisy labels, using facial expression recognition as an
example. More specifically, we have 10 taggers to label each input image, and
compare four different approaches to utilizing the multiple labels: majority
voting, multi-label learning, probabilistic label drawing, and cross-entropy
loss. We show that the traditional majority voting scheme does not perform as
well as the last two approaches that fully leverage the label distribution. An
enhanced FER+ data set with multiple labels for each face image will also be
shared with the research community.


title:
Photometric and period investigation of the late F-type overcontact
  binary II UMa

abstract:
  II UMa is a late F-type (F5) contact binary with a close-in tertiary and a
distant visual companion. According to the four-color ($B$ $V$ $R_c$ $I_c$)
light curves' solutions of II UMa, it is a high fill-out (f=$86.6\,\%$) and low
mass ratio ($q = 0.172$) contact binary system, which indicate that it is at
the late evolutionary stage of late-type tidal-locked binary stars. The mass of
the primary star and secondary one are calculated to be $M_1 = 1.99M_\odot$,
$M_2 = 0.34M_\odot$. The primary star has evolved from ZAMS, but it is still
before TAMS, and the secondary star is even more evolved. Considering the mass
ratio ($M_3/M_1 = 0.67$) obtained by spectroscopic observations, the mass of
the close-in tertiary is estimated to be $M_3 = 1.34M_\odot$. The period
variations of the binary system is investigated for the first time. According
to the observed-calculated ($O$-$C$) curve analysis, a continuous period
increase at a rate of $dP/dt=4.88\times{10^{-7}}day\cdot year^{-1}$ is
determined. It may be just a part of a cyclic period change, or the
combinational period change of a parabolic variation and a cyclic one. More
times of minimum light are needed to confirm this. The presence of the tertiary
component may play an important role in the formation and evolution of this
binary system by drawing angular momentum from the central system during the
pre-contact stage.


title:
Upper critical field and quantum oscillations in tetragonal
  superconducting FeS

abstract:
  The magnetoresistance and magnetic torque of FeS are measured in magnetic
fields $B$ of up to 18 T down to a temperature of 0.03 K. The superconducting
transition temperature is found to be $T_c$ = 4.1 K, and the anisotropy ratio
of the upper critical field $B_{c2}$ at $T_c$ is estimated from the initial
slopes to be $\Gamma(T_c)$ = 6.9. $B_{c2}(0)$ is estimated to be 2.2 and 0.36 T
for $B \parallel ab$ and $c$, respectively. Quantum oscillations are observed
in both the resistance and torque. Two frequencies $F$ = 0.15 and 0.20 kT are
resolved and assigned to a quasi-two-dimensional Fermi surface cylinder. The
carrier density and Sommerfeld coefficient associated with this cylinder are
estimated to be 5.8 $\times$ 10$^{-3}$ carriers/Fe and 0.48 mJ/(K$^2$mol),
respectively. Other Fermi surface pockets still remain to be found.
Band-structure calculations are performed and compared to the experimental
results.


title:
Non-Fermi liquid behavior of electrical resistivity close to the nematic
  critical point in Fe$_{1-x}$Co$_x$Se and FeSe$_{1-y}$S$_y$

abstract:
  Temperature dependence of resistivity of single crystals of
Fe$_{1-x}$Co$_x$Se and FeSe$_{1-y}$S$_y$ is studied in detail under zero and
high magnetic field (magnetoresistance), the latter of which enables to monitor
the temperature ($T$) evolution of resistivity below the onset of
superconducting transition temperature ($T_{\rm c}$). In FeSe$_{1-y}$S$_y$,
$T$-linear dependence of resistivity is prominent in $y$ = 0.160 below 40 K,
whereas it changes to a Fermi-liquid(FL)-like $T^2$ one below 10 K in $y$ =
0.212. These suggest that the quantum critical point (QCP) originating from the
electronic nematicity resides around $y$ = 0.160 and the fluctuation in QCP
gives rise anomalous $T$-linear dependence in resistivity in a wide $T$ range.
In Fe$_{1-x}$Co$_x$Se, resistivity gradually changes from linear- to quadratic-
$T$-dependent one at low temperatures in the range between $x$ = 0.036 and
0.075. These could be interpreted by scenarios of both the nematic QCP and the
crossover in the ground states between the orthorhombic nematic phase and the
tetragonal phase. The anomalies found as $T$-linear resistivity are discussed
in terms of orbital and spin fluctuation arising from the nematic QCP.


title:
Epitaxial growth and electronic properties of mixed valence YbAl3 thin
  films

abstract:
  We report the growth of thin films of the mixed valence compound YbAl$_{3}$
on MgO using molecular-beam epitaxy. Employing an aluminum buffer layer,
epitaxial (001) films can be grown with sub-nm surface roughness. Using x-ray
diffraction, in situ low-energy electron diffraction and aberration-corrected
scanning transmission electron microscopy we establish that the films are
ordered in the bulk as well as at the surface. Our films show a coherence
temperature of 37 K, comparable to that reported for bulk single crystals.
Photoelectron spectroscopy reveals contributions from both $\textit{f}^{13}$
and $\textit{f}^{12}$ final states establishing that YbAl$_{3}$ is a mixed
valence compound and shows the presence of a Kondo Resonance peak near the
Fermi-level.


title:
Probing the resonance of Dirac particle by the application of complex
  momentum representation

abstract:
  Resonance plays critical roles in the formation of many physical phenomena,
and several methods have been developed for the exploration of resonance. In
this work, we propose a new scheme for resonance by solving the Dirac equation
in complex momentum representation, in which the resonant states are exposed
clearly in complex momentum plane and the resonance parameters can be
determined precisely without imposing unphysical parameters. Combining with the
relativistic mean-field theory, this method is applied to probe the resonances
in $^{120}$Sn with the energies, widths, and wavefunctions being obtained.
Comparing with other methods, this method is not only very effective for narrow
resonances, but also can be reliably applied to broad resonances.


title: Localization or tunneling in asymmetric double-well potentials

abstract:
  An asymmetric double-well potential is considered, assuming that the wells
are parabolic around the minima. The WKB wave function of a given energy is
constructed inside the barrier between the wells. By matching the WKB function
to the exact wave functions of the parabolic wells on both sides of the
barrier, for two almost degenerate states, we find a quantization condition for
the energy levels which reproduces the known energy splitting formula between
the two states. For the other low-lying non-degenerate states, we show that the
eigenfunction should be primarily localized in one of the wells with negligible
magnitude in the other. Using Dekker's method [Physica 146A (1987) 375], the
present analysis generalizes earlier results for weakly biased double-well
potentials to systems with arbitrary asymmetry.


title: Gravitational wave asteroseismology with protoneutron stars

abstract:
  We examine the time evolution of the frequencies of the gravitational wave
after the bounce within the framework of relativistic linear perturbation
theory using the results of one dimensional numerical simulations of
core-collapse supernovae. Protoneutron star models are constructed in such a
way that the mass and radius of protoneutron star become equivalent to the
results obtained from the numerical simulations. Then, we find that the
frequencies of gravitational waves radiating from protoneutron stars strongly
depend on the mass and radius of protoneutron stars, but almost independently
of the profiles of electron fraction and entropy per baryon inside the star.
Additionally, we find that the frequencies of gravitational waves can be
characterized by the square root of the average density of protoneutron star
irrespectively the progenitor models, which are completely different from the
empirical formula for cold neutron stars. The dependence of the spectra on the
mass and radius is different from that of the $g$-mode: the oscillations around
the surface of protoneutron stars due to the convection and the standing
accretion-shock instability. Careful observations of the these modes of
gravitational waves can determine the evolution of the mass and radius of
protoneutron stars after core-bounce. Furthermore, the expected frequencies of
gravitational waves are around a few hundred hertz in the early stage after
bounce, which must be a good candidate for the ground-based gravitational wave
detectors.


title:
Realistic Representation of Grain Shapes in CFD--DEM Simulations of
  Sediment Transport: A Bonded-Sphere Approach

abstract:
  Development of algorithms and growth of computational resources in the past
decades have enabled simulations of sediment transport processes with
unprecedented fidelities. The Computational Fluid Dynamics--Discrete Element
Method (CFD--DEM) is one of the high-fidelity approaches, where the motions of
and collisions among the sediment grains as well as their interactions with
surrounding fluids are resolved. In most DEM solvers the particles are modeled
as soft spheres due to computational efficiency and implementation complexity
considerations, although natural sediments are usually mixture of non-spherical
particles. Previous attempts to extend sphere-based DEM to treat irregular
particles neglected fluid-induced torques on particles, and the method lacked
flexibility to handle sediments with an arbitrary mixture of particle shapes.
In this contribution we proposed a simple, efficient approach to represent
common sediment grain shapes with bonded spheres, where the fluid forces are
computed and applied on each sphere. The proposed approach overcomes the
aforementioned limitations of existing methods and has improved efficiency and
flexibility over existing approaches. We use numerical simulations to
demonstrate the merits and capability of the proposed method in predicting the
falling characteristics, terminal velocity, threshold of incipient motion, and
transport rate of natural sediments. The simulations show that the proposed
method is a promising approach for faithful representation of natural sediment,
which leads to accurate simulations of their transport dynamics. The proposed
method also opens the possibility for first-principle-based simulations of the
flocculation and sedimentation dynamics of cohesive sediments. Elucidation of
these physical mechanisms can provide much needed improvement on the prediction
capability and physical understanding of muddy coast dynamics.


title:
A Solar-type Stellar Companion to a Deep Contact Binary in a Quadruple
  System

abstract:
  The four-color ($B$ $V$ $R_c$ $I_c$) light curves of V776 Cas are presented
and analyzed using the Wilson-Devinney (W-D) method. It is discovered that V776
Cas is an early F-type (F2V) overcontact binary with a very high contact degree
($ f=64.6\,\%$) and an extremely low mass ratio ($q=0.130$), which indicate
that it is at the final evolutionary stage of cool short-period binaries. The
mass of the primary and secondary stars are calculated to be $M_1 =
1.55(\pm0.04)M_\odot$, $M_2 = 0.20(\pm0.01)M_\odot$. V776 Cas is supposed to be
formed from an initially detached binary system via the loss of angular
momentum due to the magnetic wind. The initial mass of the present primary and
secondary components are calculated to be $M_{1i} = 0.86(\pm0.10)M_\odot$ and
$M_{2i} = 2.13(\pm0.04)M_\odot$. The observed-calculated ($O$-$C$) curve
exhibits a cyclic period variation, which is due to the light-travel time
effect (LTTE) caused by the presence of a third component with a period of 23.7
years. The mass of the third component is estimated to be $M_3 =
1.04(\pm0.03)M_\odot$ and the orbital inclination of the third component is
calculated to be $i' = 33.1^{\circ}$. The distance of the binary system to the
mass center of the triple system is calculated to be $a'_{12} = 3.45AU$. The
presence of the close-in tertiary component may play an important role in the
formation and evolution of this binary system by drawing angular momentum from
the central system.


title: Rokhlin dimension of Z^m actions on simple C*-algebras

abstract:
  We study Rokhlin dimension of Z^m-actions on simple separable stably finite
nuclear C*-algebras. We prove that under suitable assumptions, a strongly outer
Z^m-action has finite Rokhlin dimension. This extends the known result for
automorphisms. As an application, we show that for a large class of
C*-algebras, the Z^m-Bernoulli action on the infinite tensor product has finite
Rokhlin dimension.


title: Low-lying energy bands in a finite periodic multiple-well potential

abstract:
  We analyze the low-lying states for a one-dimensional potential consisting of
$N$ identical wells, assuming that the wells are parabolic around the minima.
Matching the exact wave functions around the minima and the WKB wave functions
in the barriers, we find a quantization condition which is then solved to give
a formula for the energy eigenvalues explicitly written in terms of the
potential. In addition, constructing $N$ localized approximate eigenstates each
of which matches on to that of the harmonic oscillator in one of the parabolic
wells, and diagonalizing the Hamiltonian in the subspace spanned by the
localized states on the assumption that the localized states form an orthogonal
basis, we also find the same formula for the energy eigenvalues which the
method of matching the wave functions gives. In the large-$N$ limit, the
formula reproduces, at the leading order, the expression for the widths of the
narrow energy bands of the Mathieu equation present in the mathematical
literature. As there are differences between the $N$-well system in the
large-$N$ limit and the fully periodic system, we include a two-dimensional
model in which the quadratic minima are located on the vertices of a regular
$N$-sided polygon with rotational symmetry of order $N$. We argue that the
lowest band of the two-dimensional model closely resembles the tight-binding
energy bands of the fully periodic one-dimensional system in that most of the
eigenvalues are degenerate in the large-$N$ limit with the eigenfunctions
satisfying the Bloch condition under the discrete rotations.


title:
Intrinsic coherent acoustic phonons in indirect band gap semiconductors
  Si and GaP

abstract:
  We report on the intrinsic optical generation and detection of coherent
acoustic phonons at (001)-oriented bulk Si and GaP without metallic phonon
transducer structures. Photoexcitation by a 3.1-eV laser pulse generates a
normal strain pulse within the $\sim$100-nm penetration depth in both
semiconductors. The subsequent propagation of the strain pulse into the bulk is
detected with a delayed optical probe as a periodic modulation of the optical
reflectivity. Our theoretical model explains quantitatively the generation of
the acoustic pulse via the deformation potential electron-phonon coupling and
detection in terms of the spatially and temporally dependent photoelastic
effect for both semiconductors. Comparison with our theoretical model reveals
that the experimental strain pulses have finite build-up times of 1.2 and 0.4
ps for GaP and Si, which are comparable with the time required for the
photoexcited electrons to transfer to the lowest X valley through intervalley
scattering. The deformation potential coupling related to the acoustic pulse
generation for GaP is estimated to be twice as strong as that for Si from our
experiments, in agreement with a previous theoretical prediction.


title:
The first photometric analysis of the W-subtype contact binary UCAC4
  436-062932 with O'Connell effect

abstract:
  Two sets of light curves in $V$ $R_c$ $I_c$ bands for a newly discovered
binary system UCAC4 436-062932 are obtained and analyzed using the
Wilson-Devinney (W-D) code. The two sets of light curves get almost consistent
results. The determined mass ratio is about $q = 2.7$ and the less massive
component is nearly $250K$ hotter than the more massive one. The solutions
conclude that UCAC4 436-062932 is a W-subtype shallow contact (with a contact
degree of $f = 20\,\%$) binary system. Since the O'Connell effect appears on
one set of the light curves, theories proposed to explain the effect are
discussed. We assume that spot model may be the more plausible one to the
O'Connell effect appeared on the asymmetric light curves of the binary system
UCAC4 436-062932. Therefore, we add a cool spot on the surface of the more
massive star (component with lower effective temperature) and get a quite
approving results for the light curve fitting. It will provide evidence to
support the spot model in the explanatory mechanism of O'Connell effect.


title:
A comparative study of intervening and associated HI 21-cm absorption
  profiles in redshifted galaxies

abstract:
  The star-forming reservoir in the distant Universe can be detected through HI
21-cm absorption arising from either cool gas associated with a radio source or
from within a galaxy intervening the sight-line to the continuum source. In
order to test whether the nature of the absorber can be predicted from the
profile shape, we have compiled and analysed all of the known redshifted (z >
0.1) HI 21-cm absorption profiles. Although between individual spectra there is
too much variation to assign a typical spectral profile, we confirm that
associated absorption profiles are on average, wider than their intervening
counterparts. It is widely hypothesised that this is due to high velocity
nuclear gas feeding the central engine, absent in the more quiescent
intervening absorbers. Modelling the column density distribution of the mean
associated and intervening spectra, we confirm that the additional low optical
depth, wide dispersion component, typical of associated absorbers, arises from
gas within the inner parsec. With regard to the potential of predicting the
absorber type in the absence of optical spectroscopy, we have implemented
machine learning techniques to the 55 associated and 43 intervening spectra,
with each of the tested models giving a >80% accuracy in the prediction of the
absorber type. Given the impracticability of follow-up optical spectroscopy of
the large number of 21-cm detections expected from the next generation of large
radio telescopes, this could provide a powerful new technique with which to
determine the nature of the absorbing galaxy.


title: Morphological Priors for Probabilistic Neural Word Embeddings

abstract:
  Word embeddings allow natural language processing systems to share
statistical information across related words. These embeddings are typically
based on distributional statistics, making it difficult for them to generalize
to rare or unseen words. We propose to improve word embeddings by incorporating
morphological information, capturing shared sub-word features. Unlike previous
work that constructs word embeddings directly from morphemes, we combine
morphological and distributional information in a unified probabilistic
framework, in which the word embedding is a latent variable. The morphological
information provides a prior distribution on the latent word embeddings, which
in turn condition a likelihood function over an observed corpus. This approach
yields improvements on intrinsic word similarity evaluations, and also in the
downstream task of part-of-speech tagging.


title:
The photometric investigation of the newly discovered W UMa type binary
  system GSC 03122-02426

abstract:
  The $B$ $V$ $R_c$ $I_c$ bands light curves of the newly discovered binary
system \astrobj{GSC 03122-02426} are obtained and analyzed using the
Wilson-Devinney (W-D) code. The solutions suggest that the mass ratio of the
binary system is $q = 2.70$ and the less massive component is $422K$ hotter
than the more massive one. We conclude that \astrobj{GSC 03122-02426} is a
W-subtype shallow contact (with a contact degree of $f = 15.3\,\%$) binary
system. It may be a newly formed contact binary system which is just under
geometrical contact and will evolve to be a thermal contact binary system. The
high orbital inclination ($i = 81.6^{\circ}$) implies that \astrobj{GSC
03122-02426} is a total eclipsing binary system and the photometric parameters
obtained by us are quite reliable. We also estimate the absolute physical
parameters of the two components in \astrobj{GSC 03122-02426}, which will
provide fundamental information for the research of contact binary systems. The
formation and evolutionary scenario of \astrobj{GSC 03122-02426} is discussed.


title:
Substituent-Controlled Reversible Switching of Charge-Injection-Barrier
  Heights at Metal/Organic-Semiconductor Contacts Modified with Disordered
  Molecular Monolayers

abstract:
  Electrically stimulated switching of a charge injection barrier at the
interface between an organic semiconductor and an electrode modified with a
disordered monolayer (DM) is studied by using various benzenethiol derivatives
as DM molecules. The switching behavior is induced by a structural change in
the DM molecules, and is manifested as a reversible inversion of the polarity
of DM-modified Au electrode/rubrene/DM-modified Au electrode diodes. The
switching direction is found to be dominantly determined by the push-back
effect of the thiol bonding group, while the terminal group modulates the
switching strength. A device with 1,2-benzenedithiol DMs exhibited the highest
switching ratios of 20, 100, and 1000 for the switching voltages of 3, 5, and 7
V, respectively. A variation in the tilt angle of benzenethiol DMs owing to the
application of 7 V is estimated to be smaller than 23.6 degrees by model
calculations. This study offers an understanding for obtaining highly stable
operations of organic electronic devices, especially with molecular
modification layers.


title: Analyzing Linear Dynamical Systems: From Modeling to Coding and Learning

abstract:
  Encoding time-series with Linear Dynamical Systems (LDSs) leads to rich
models with applications ranging from dynamical texture recognition to video
segmentation to name a few. In this paper, we propose to represent LDSs with
infinite-dimensional subspaces and derive an analytic solution to obtain stable
LDSs. We then devise efficient algorithms to perform sparse coding and
dictionary learning on the space of infinite-dimensional subspaces. In
particular, two solutions are developed to sparsely encode an LDS. In the first
method, we map the subspaces into a Reproducing Kernel Hilbert Space (RKHS) and
achieve our goal through kernel sparse coding. As for the second solution, we
propose to embed the infinite-dimensional subspaces into the space of symmetric
matrices and formulate the sparse coding accordingly in the induced space. For
dictionary learning, we encode time-series by introducing a novel concept,
namely the two-fold LDSs. We then make use of the two-fold LDSs to derive an
analytical form for updating atoms of an LDS dictionary, i.e., each atom is an
LDS itself. Compared to several baselines and state-of-the-art methods, the
proposed methods yield higher accuracies in various classification tasks
including video classification and tactile recognition.


title: Nonlocal Galileons and Self-Acceleration

abstract:
  A certain class of nonlocal theories eliminates an arbitrary cosmological
constant (CC) from a universe that can be perceived as our world. Dark energy
then cannot be explained by a CC; it could however be due to massive gravity.
We calculate the new corrections, which originate from the nonlocal terms that
eliminate the CC, to the decoupling limit Lagrangian of massive gravity. The
new nonlocal terms also have internal field space Galilean symmetry and are
referred here as "nonlocal Galileons." We then study a self-accelerated
solution and show that the new nonlocal terms change the perturbative stability
analysis. In particular, small fluctuations are now stable and non-superluminal
for some simple parameter choices, whereas for the same choices the pure
massive gravity fluctuations are unstable. We also study stable spherically
symmetric solutions on this background.


title:
Edge-induced Schottky barrier modulation at metal contacts to exfoliated
  molybdenum disulfide flakes

abstract:
  Ultrathin two-dimensional semiconductors obtained from layered
transition-metal dichalcogenides such as molybdenum disulfide (MoS2) are
promising for ultimately scaled transistors beyond Si. Although the shortening
of the semiconductor channel is widely studied, the narrowing of the channel,
which should also be important for scaling down the transistor, has been
examined to a lesser degree thus far. In this study, the impact of narrowing on
mechanically exfoliated MoS2 flakes was investigated according to the
channel-width-dependent Schottky barrier heights at Cr/Au contacts. Narrower
channels were found to possess a higher Schottky barrier height, which is
ascribed to the edge-induced band bending in MoS2. The higher barrier heights
degrade the transistor performance as a higher electrode-contact resistance.
Theoretical analyses based on Poisson's equation showed that the edge-induced
effect can be alleviated by a high dopant impurity concentration, but this
strategy should be limited to channel widths of roughly 0.7 micrometers because
of the impurity-induced charge-carrier mobility degradation. Therefore, proper
termination of the dangling bonds at the edges should be necessary for
aggressive scaling with layered semiconductors.


title:
The emergence and analysis of Kuramoto-Sakaguchi-like models as an
  effective description for the dynamics of coupled Wien-bridge oscillators

abstract:
  We derive the Kuramoto-Sakaguchi model from the basic circuit equations
governing two coupled Wien-bridge oscillators. A Wien-bridge oscillator is a
particular realization of a tunable autonomous oscillator that makes use of
frequency filtering (via a RC band-pass filter) and positive feedback (via an
Op-Amp). In the last few years, such oscillators have started to be utilized in
synchronization studies. We first show that the Wien-bridge circuit equations
can be cast in the form of a coupled pair of Duffing - Van der Pol equations.
Subsequently, by applying the method of multiple time scales, we derive the
differential equations that govern the slow evolution of the oscillator phases
and amplitudes. These equations are directly reminiscent of the
Kuramoto-Sakaguchi type models for the study of synchronization. We analyze the
resulting system in terms of existence and stability of various coupled
oscillator solutions and explain on that basis how their synchronization
emerges. The phase-amplitude equations are also compared numerically to the
original circuit equations, and good agreement is found. Finally, we report on
experimental measurements on two coupled Wien-bridge oscillators and relate the
results back to the theoretical predictions.


title: Researches on a reactor core in heavy ion inertial fusion

abstract:
  In this paper a study on a fusion reactor core is presented in heavy ion
inertial fusion (HIF), including the heavy ion beam (HIB) transport in a fusion
reactor, a HIB interaction with a background gas, reactor cavity gas dynamics,
the reactor gas backflow to the beam lines, and a HIB fusion reactor design.
The HIB has remarkable preferable features to release the fusion energy in
inertial fusion: in particle accelerators HIBs are generated with a high driver
efficiency of ~30-40%, and the HIB ions deposit their energy inside of
materials. Therefore, a requirement for the fusion target energy gain is
relatively low, that would be ~50 to operate a HIF fusion reactor with a
standard energy output of 1GW of electricity. In a fusion reactor the HIB
charge neutralization is needed for a ballistic HIB transport. Multiple
mechanical shutters would be installed at each HIB port at the reactor wall to
stop the blast waves and the chamber gas backflow, so that the accelerator
final elements would be protected from the reactor gas contaminant. The
essential fusion reactor components are discussed in this paper.


title:
Control of fuel target implosion non-uniformity in heavy ion inertial
  fusion

abstract:
  In inertial fusion, one of scientific issues is to reduce an implosion
non-uniformity of a spherical fuel target. The implosion non-uniformity is
caused by several factors, including the driver beam illumination
non-uniformity, the Rayleigh-Taylor instability (RTI) growth, etc. In this
paper we propose a new control method to reduce the implosion non-uniformity;
the oscillating implosion acceleration dg(t) is created by pulsating and
dephasing heavy ion beams (HIBs) in heavy ion inertial fusion (HIF). The dg(t)
would reduce the RTI growth effectively. The original concept of the non-
uniformity control in inertial fusion was proposed in (Kawata, et al., 1993).
In this paper it was found that the pulsating and dephasing HIBs illumination
provide successfully the controlled dg(t) and that dg(t) induced by the
pulsating HIBs reduces well the implosion non-uniformity. Consequently the
pulsating HIBs improve a pellet gain remarkably in HIF.


title: Open Quantum Random Walks, Quantum Markov Chains and Recurrence

abstract:
  In the present paper, we construct QMCs associated with Open Quantum Random
Walks such that the transition operator of the chain is defined by OQRW and the
restriction of QMC to the commutative subalgebra coincides with the
distribution $P_\rho$ of OQRW. This sheds new light on some properties of the
measure $P_\rho$. As an example, we simply mention that the measure can be
considered as a distribution of some functions of certain Markov process.
Furthermore, we study several properties of QMC and associated measure. A new
notion of $\f$-recurrence of QMC is studied, and it is established relations
between the defined recurrence and the existing ones.

categories: math.FA math-ph math.MP math.PR quant-ph


title:
Study of Localized Character of 4f Electrons and Ultrasonic Dispersions
  in SmOs4Sb12 by High-Pressure High-Frequency Ultrasonic Measurements

abstract:
  We present high-frequency ultrasonic measurements on the filled skutterudite
SmOs$_4$Sb$_{12}$ under hydrostatic pressure. The results clarify that the 4$f$
electrons in this compound transform from delocalized at ambient pressure to
localized at high pressures with a crossover pressure of approximately 0.7 GPa.
This drastic change in the 4$f$ electrons under pressure is apparently related
to the non-Fermi liquid state, which appears in an intermediate-pressure range
of 0.5-1.5 GPa. The results or our analysis strongly suggest that the
ferro-octupolar interaction becomes dominant at high pressure. Moreover, we
report the pressure dependence of the ultrasonic dispersion, which is due to
rattling, over a wide range of ultrasonic frequencies up to 323 MHz. The
drastic change in the ultrasonic dispersions and the frequency dependent
elastic anomaly in the $C_{11}$ mode at lower temperatures imply a possible
coupling between rattling phonons and 4$f$ electrons.


title: Sympathetic Solar Filament Eruptions on 2015 March 15

abstract:
  The 2015 March 15 coronal mass ejection as one of the two that together drove
the largest geomagnetic storm of solar cycle 24 so far was associated with
sympathetic filament eruptions. We investigate the relations between the
different filaments involved in the eruption. A surge-like small-scale filament
motion is confirmed as the trigger that initiated the erupting filament with
multi-wavelength observations and using a forced magnetic field extrapolation
method. When the erupting filament moved to an open magnetic field region, it
experienced an obvious acceleration process and was accompanied by a C-class
flare and the rise of another larger filament that eventually failed to erupt.
We measure the decay index of the background magnetic field, which presents a
critical height of 118 Mm. Combining with a potential field source surface
extrapolation method, we analyze the distributions of the large-scale magnetic
field, which indicates that the open magnetic field region may provide a
favorable condition for F2 rapid acceleration and have some relation with the
largest solar storm. The comparison between the successful and failed filament
eruptions suggests that the confining magnetic field plays an important role in
the preconditions for an eruption.


title: Ranking Entity Based on Both of Word Frequency and Word Sematic Features

abstract:
  Entity search is a new application meeting either precise or vague
requirements from the search engines users. Baidu Cup 2016 Challenge just
provided such a chance to tackle the problem of the entity search. We achieved
the first place with the average MAP scores on 4 tasks including movie, tvShow,
celebrity and restaurant. In this paper, we propose a series of similarity
features based on both of the word frequency features and the word semantic
features and describe our ranking architecture and experiment details.


title: An Abstract Model of Historical Processes

abstract:
  A theoretical model is presented which provides a way to simulate, at a very
abstract level, power struggles in the social world. In the model, agents can
benefit or harm each other, to varying degrees and with differing levels of
influence. The agents interact over time, using the power they have to try to
get more of it, while being constrained in their strategic choices by social
inertia. The outcomes of the model are probabilistic. More research is needed
to determine whether the model has any empirical validity.