title:
A Giant Planet beyond the Snow Line in Microlensing Event
  OGLE-2011-BLG-0251

abstract:
  We present the analysis of the gravitational microlensing event
OGLE-2011-BLG-0251. This anomalous event was observed by several survey and
follow-up collaborations conducting microlensing observations towards the
Galactic Bulge. Based on detailed modelling of the observed light curve, we
find that the lens is composed of two masses with a mass ratio q=1.9 x 10^-3.
Thanks to our detection of higher-order effects on the light curve due to the
Earth's orbital motion and the finite size of source, we are able to measure
the mass and distance to the lens unambiguously. We find that the lens is made
up of a planet of mass 0.53 +- 0.21,M_Jup orbiting an M dwarf host star with a
mass of 0.26 +- 0.11 M_Sun. The planetary system is located at a distance of
2.57 +- 0.61 kpc towards the Galactic Centre. The projected separation of the
planet from its host star is d=1.408 +- 0.019, in units of the Einstein radius,
which corresponds to 2.72 +- 0.75 AU in physical units. We also identified a
competitive model with similar planet and host star masses, but with a smaller
orbital radius of 1.50 +- 0.50 AU. The planet is therefore located beyond the
snow line of its host star, which we estimate to be around 1-1.5 AU.


title:
Gravitational Wave Tests of Strong Field General Relativity with Binary
  Inspirals: Realistic Injections and Optimal Model Selection

abstract:
  We study generic tests of strong-field General Relativity using gravitational
waves emitted during the inspiral of compact binaries. Previous studies have
considered simple extensions to the standard post-Newtonian waveforms that
differ by a single term in the phase. Here we improve on these studies by (i)
increasing the realism of injections and (ii) determining the optimal waveform
families for detecting and characterizing such signals. We construct waveforms
that deviate from those in General Relativity through a series of
post-Newtonian terms, and find that these higher-order terms can affect our
ability to test General Relativity, in some cases by making it easier to detect
a deviation, and in some cases by making it more difficult. We find that simple
single-phase post-Einsteinian waveforms are sufficient for detecting deviations
from General Relativity, and there is little to be gained from using more
complicated models with multiple phase terms. The results found here will help
guide future attempts to test General Relativity with advanced ground-based
detectors.


title: Strangelets and the TeV-PeV cosmic-ray anisotropies

abstract:
  Several experiments (e.g., Milagro and IceCube) have reported the presence in
the sky of regions with significant excess in the arrival direction
distributions of Galactic cosmic rays in the TeV to PeV energy range. Here we
study the possibility that these hotspots are a manifestation of the peculiar
nature of these cosmic rays, and of the presence of molecular clouds near the
sources. We propose that stable quark matter lumps or so-called "strangelets"
can be emitted in the course of the transition of a neutron star to a more
compact astrophysical object. A fraction of these massive particles would lose
their charge by spallation or electron capture in molecular clouds located in
the immediate neighborhood of their source, and propagate rectilinearly without
decaying further, hence inducing anisotropies of the order of the cloud size.
With reasonable astrophysical assumptions regarding the neutron star transition
rate, strangelet injection and neutralization rates, we can reproduce
successfully the observed hotspot characteristics and their distribution in the
sky.


title: Superconducting proximity effect in semiconductor nanowires

abstract:
  We theoretically consider the proximity effect in
semiconductor-superconductor hybrid nanostructures, which are being extensively
studied in the context of the ongoing search for non-Abelian Majorana fermions
in solid state systems. Specifically, we consider the dependence on the
thickness of the semiconductor in the direction normal to the interface, a
physical effect that has been uncritically neglected in all prior work on the
subject. Quite surprisingly, we find the completely unanticipated result that
increasing the semiconductor thickness leads to a drastic suppression of the
induced superconducting gap due to proximity-induced interband coupling. As a
result, in the limit of strong semiconductor-superconductor coupling, the
proximity-induced gap becomes much smaller than the bulk superconductor gap and
depends weakly on the interface transparency.


title: High sensitivity optomechanical reference accelerometer over 10 kHz

abstract:
  We present an optically-detected mechanical accelerometer that achieves a
sensitivity of 100 ng/rtHz over a bandwidth of 10kHz and is traceable. We have
incorporated a Fabry-Perot fiber-optic micro-cavity that is currently capable
of measuring the test-mass displacement with sensitivities of 200 am/rtHz, and
whose length determination enables traceability to the International System of
Units (SI). The compact size and high mQ-product achieved combined with the
high sensitivity and simplicity of the implemented optical detection scheme
highlight our device and this category of accelerometers, outlining a path for
high sensitivity reference acceleration measurements and observations in
seismology and gravimetry.

categories: physics.optics gr-qc physics.geo-ph physics.ins-det quant-ph


title: Theoretical issues in PDF determination and associated uncertainties

abstract:
  We study several sources of theoretical uncertainty in the determination of
parton distributions (PDFs) which may affect current PDF sets used for
precision physics at the Large Hadron Collider, and explain discrepancies
between them. We consider in particular the use of fixed-flavor versus
variable-flavor number renormalization schemes, higher twist corrections, and
nuclear corrections. We perform our study in the framework of the NNPDF2.3
global PDF determination, by quantifying in each case the impact of different
theoretical assumptions on the output PDFs. We also study in each case the
implications for benchmark cross sections at the LHC. We find that the impact
in a global fit of a fixed-flavor number scheme is substantial, the impact of
higher twists is negligible, and the impact of nuclear corrections is moderate
and circumscribed.


title: Bolometric and UV Light Curves of Core-Collapse Supernovae

abstract:
  The Swift UV-Optical Telescope (UVOT) has been observing Core-Collapse
Supernovae (CCSNe) of all subtypes in the UV and optical since 2005. We present
here 50 CCSNe observed with the Swift UVOT, analyzing their UV properties and
behavior. Where we have multiple UV detections in all three UV filters (\lambda
c = 1928 - 2600 \AA), we generate early time bolometric light curves, analyze
the properties of these light curves, the UV contribution to them, and derive
empirical corrections for the UV-flux contribution to optical-IR based
bolometric light curves.


title:
Entropy at the Outskirts of Galaxy Clusters as Implications for
  Cosmological Cosmic-Ray Acceleration

abstract:
  Recently, gas entropy at the outskirts of galaxy clusters attracts much
attention. We propose that the entropy profiles could be used to study
cosmic-ray (CR) acceleration around the clusters. If the CRs are effectively
accelerated at the formation of clusters, the kinetic energy of infalling gas
is consumed by the acceleration and the gas entropy should decrease. As a
result, the entropy profiles become flat at the outskirts. If the acceleration
is not efficient, the entropy should continue to increase outwards. By
comparing model predictions with X-ray observations with Suzaku, which show
flat entropy profiles, we find that the CRs have carried ~<7% of the kinetic
energy of the gas away from the clusters. Moreover, the CR pressure at the
outskirts can be ~<40% of the total pressure. On the other hand, if the entropy
profiles are not flat at the outskirts as indicated by combined Plank and ROSAT
observations, the carried energy and the CR pressure should be much smaller
than the above estimations.


title: Angle-Dependent Spin-Wave Resonance Spectroscopy of (Ga,Mn)As Films

abstract:
  A modeling approach for standing spin-wave resonances based on a
finite-difference formulation of the Landau-Lifshitz-Gilbert equation is
presented. In contrast to a previous study [Bihler et al., Phys. Rev. B 79,
045205 (2009)], this formalism accounts for elliptical magnetization precession
and magnetic properties arbitrarily varying across the layer thickness,
including the magnetic anisotropy parameters, the exchange stiffness, the
Gilbert damping, and the saturation magnetization. To demonstrate the
usefulness of our modeling approach, we experimentally study a set of (Ga,Mn)As
samples grown by low-temperature molecular-beam epitaxy by means of
electrochemical capacitance-voltage measurements and angle-dependent standing
spin-wave resonance spectroscopy. By applying our modeling approach, the angle
dependence of the spin-wave resonance data can be reproduced in a simulation
with one set of simulation parameters for all external field orientations. We
find that the approximately linear gradient in the out-of-plane magnetic
anisotropy is related to a linear gradient in the hole concentrations of the
samples.


title:
One-particle-irreducible consistency relations for cosmological
  perturbations

abstract:
  We derive consistency relations for correlators of scalar cosmological
perturbations which hold in the "squeezed limit" in which one or more of the
external momenta become soft. Our results are formulated as relations between
suitably defined one-particle irreducible N-point and (N-1)-point functions
that follow from residual spatial conformal diffeomorphisms of the unitary
gauge Lagrangian. As such, some of these relations are exact to all orders in
perturbation theory, and do not rely on approximate deSitter invariance or
other dynamical assumptions (e.g., properties of the operator product expansion
or the behavior of modes at horizon crossing). The consistency relations apply
model-independently to cosmological scenarios where the time evolution is
driven by a single scalar field. Besides reproducing the known results for
single-field inflation in the slow roll limit, we verify that our consistency
relations hold more generally, for instance in ghost condensate models in flat
space. We comment on possible extensions of our results to multi-field models.


title: Dynamics and relaxation in spin nematics

abstract:
  We study dynamics and relaxation of elementary excitations (magnons) in the
spin nematic (quadrupole ordered) phase of S=1 magnets. We develop a general
phenomenological theory of spin dynamics and relaxation for spin-1 systems.
Results of the phenomenological approach are compared to those obtained by
microscopic calculations for the specific S=1 model with isotropic bilinear and
biquadratic exchange interactions. This model exhibits a rich behavior
depending on the ratio of bilinear and biquadratic exchange constants,
including several points with an enhanced symmetry. It is shown that symmetry
plays an important role in relaxation. Particularly, at the SU(3) ferromagnetic
point the magnon damping $\Gamma$ depends on its wavevector k as $\Gamma\propto
k^{4}$, while a deviation from the high-symmetry point changes the behavior of
the leading term to $\Gamma\propto k^{2}$. We point out a similarity between
the behavior of magnon relaxation in spin nematics to that in an isotropic
ferromagnet.


title:
The gap between near commutativity and almost commutativity in
  symplectic category

abstract:
  On any symplectic manifold of dimension greater than 2, we construct a pair
of smooth functions, such that on the one hand, the uniform norm of their
Poisson bracket equals to 1, but on the other hand, this pair cannot be
reasonably approximated (in the uniform norm) by a pair of Poisson commuting
smooth functions. This comes in contrast with the dimension 2 case, where by a
partial case of a result of Zapolsky, an opposite statement holds.


title: Higher integrability for minimizers of the Mumford-Shah functional

abstract:
  We prove higher integrability for the gradient of local minimizers of the
Mumford-Shah energy functional, providing a positive answer to a conjecture of
De Giorgi.


title:
Red Giants in Eclipsing Binary and Multiple-Star Systems: Modeling and
  Asteroseismic Analysis of 70 Candidates from Kepler Data

abstract:
  Red-giant stars are an incredible source of information for testing models of
stellar evolution, as asteroseismology has opened up a window into their
interiors. Such insights are a direct result of the unprecedented data from
space missions Kepler and CoRoT as well as recent theoretical advances.
Eclipsing binaries are also fundamental astrophysical objects, and when coupled
with asteroseismology, binaries would provide two independent methods to obtain
masses and radii and exciting opportunities to develop highly constrained
stellar models. The possibility of discovering pulsating red giants in
eclipsing binary systems is therefore an important goal that could potentially
offer very robust characterization of these systems. Hitherto, only 1 case has
been discovered with Kepler. We cross-correlated the detected red-giant and
eclipsing-binary catalogs from Kepler data to find candidate systems.
Light-curve modeling and mean asteroseismic properties are combined to yield
measurements of periods, masses, radii, temperatures, eclipse timing
variations, core rotation rates, and red-giant evolutionary state. After
elimination of false positives, out of the 70 systems common to the red-giant
and eclipsing-binary catalogs we find 13 new strong candidates that are
pulsating red giants in eclipsing binaries, and 10 more that are pulsating red
giants in hierarchical triple systems. The systems span a range of orbital
eccentricities, periods, and spectral types for the red-giant companion. One
case even suggests a system composed of two red-giants. The discovery of
pulsating red giants in multiple systems provides exciting test beds for
precise astrophysical modeling, and follow-up spectroscopic observations of the
candidate systems are encouraged.


title:
Long term variability of Cygnus X-1 V. State definitions with all sky
  monitors

abstract:
  We present a scheme to determine the spectral state of the canonical black
hole Cyg X-1 using data from previous and current X-ray all sky monitors
(RXTE-ASM, Swift-BAT, MAXI, and Fermi-GBM). State determinations of the
hard/intermediate and soft state agree to better than 10% between different
monitors, facilitating the determination of the state and its context for any
observation of the source, potentially over the lifetimes of different
individual monitors. A separation of the hard and the intermediate state, which
strongly differ in their spectral shape and short-term timing behavior, is only
possible when monitor data in the soft X-rays (<5 keV) are available. A
statistical analysis of the states confirms the different activity patterns of
the source (e.g., months to years long hard state periods or phases during
which numerous transitions occurs). It also shows the hard and soft states to
be stable, with the probability of Cyg X-1 remaining in a given state for at
least one week to be larger than 85% for the hard state and larger than 75%,
for the soft state. Intermediate states are short lived, with a probability of
50% that the source leaves the intermediate state within three days. A reliable
detection of these potentially short-lived events is only possible with monitor
data with a time resolution of better than 1 d.


title: Bulk--Boundary Correspondence for Chiral Symmetric Quantum Walks

abstract:
  Discrete-time quantum walks (DTQW) have topological phases that are richer
than those of time-independent lattice Hamiltonians. Even the basic symmetries,
on which the standard classification of topological insulators hinges, have not
yet been properly defined for quantum walks. We introduce the key tool of
timeframes, i.e., we describe a DTQW by the ensemble of time-shifted unitary
timestep operators belonging to the walk. This gives us a way to consistently
define chiral symmetry (CS) for DTQW's. We show that CS can be ensured by using
an "inversion symmetric" pulse sequence. For one-dimensional DTQW's with CS, we
identify the bulk ZxZ topological invariant that controls the number of
topologically protected 0 and pi energy edge states at the interfaces between
different domains, and give simple formulas for these invariants. We illustrate
this bulk--boundary correspondence for DTQW's on the example of the "4-step
quantum walk", where tuning CS and particle-hole symmetry realizes edge states
in various symmetry classes.


title:
Transverse Top Quark Polarization and the ttbar Forward-Backward
  Asymmetry

abstract:
  The forward-backward asymmetry in top pair production at the Tevatron has
long been in tension with the Standard Model prediction. One of the only viable
new physics scenarios capable of explaining this anomaly is an s-channel
axigluon-like resonance, with the quantum numbers of the gluon but with
significant axial couplings to quarks. While such a resonance can lead to a
clear bump or excess in the ttbar or dijet mass spectra, it may also simply be
too broad to cleanly observe. Here, we point out that broad ttbar resonances
generally lead to net top and antitop polarizations transverse to the
production plane. This polarization is consistent with all discrete spacetime
symmetries, and, analogous to the forward-backward asymmetry itself, is absent
in QCD at leading order. Within the parameter space consistent with the
asymmetry measurements, the induced polarization can be sizable, and might be
observable at the Tevatron or the LHC.


title: Multi-Pair Amplify-and-Forward Relaying with Very Large Antenna Arrays

abstract:
  We consider a multi-pair relay channel where multiple sources simultaneously
communicate with destinations using a relay. Each source or destination has
only a single antenna, while the relay is equipped with a very large antenna
array. We investigate the power efficiency of this system when maximum ratio
combining/maximal ratio transmission (MRC/MRT) or zero-forcing (ZF) processing
is used at the relay. Using a very large array, the transmit power of each
source or relay (or both) can be made inversely proportional to the number of
relay antennas while maintaining a given quality-of-service. At the same time,
the achievable sum rate can be increased by a factor of the number of
source-destination pairs. We show that when the number of antennas grows to
infinity, the asymptotic achievable rates of MRC/MRT and ZF are the same if we
scale the power at the sources. Depending on the large scale fading effect,
MRC/MRT can outperform ZF or vice versa if we scale the power at the relay.


title: On Metaplectic Modular Categories and their applications

abstract:
  For non-abelian simple objects in a unitary modular category, the density of
their braid group representations, the #P-hard evaluation of their associated
link invariants, and the BQP-completeness of their anyonic quantum computing
models are closely related. We systematically study such properties of the
non-abelian simple objects in metaplectic modular categories, which are unitary
modular categories with fusion rules of SO(m)_2 for an odd integer m \geq 3.
The simple objects with quantum dimensions \sqrt{m} have finite image braid
group representations, and their link invariants are classically efficient to
evaluate. We also provide classically efficient simulation of their braid group
representations. These simulations of the braid group representations can be
regarded as qudit generalizations of the Knill-Gottesmann theorem for the qubit
case. The simple objects of dimension 2 give us a surprising result: while
their braid group representations have finite images and are efficiently
simulable classically after a generalized localization, their link invariants
are #P-hard to evaluate exactly. We sharpen the #P-hardness by showing that any
sufficiently accurate approximation of their associated link invariants is
already #P-hard.


title:
Possible surface plasmon polariton excitation under femtosecond laser
  irradiation of silicon

abstract:
  The mechanisms of ripple formation on silicon surface by femtosecond laser
pulses are investigated. We demonstrate the transient evolution of the density
of the excited free-carriers. As a result, the experimental conditions required
for the excitation of surface plasmon polaritons are revealed. The periods of
the resulting structures are then investigated as a function of laser
parameters, such as the angle of incidence, laser fluence, and polarization.
The obtained dependencies provide a way of better control over the properties
of the periodic structures induced by femtosecond laser on the surface of a
semiconductor material.


title: Nanoscale fluorescence lifetime imaging with a single diamond NV center

abstract:
  Solid-state quantum emitters, such as artificially engineered quantum dots or
naturally occurring defects in solids, are being investigated for applications
ranging from quantum information science and optoelectronics to biomedical
imaging. Recently, these same systems have also been studied from the
perspective of nanoscale metrology. In this letter we study the near-field
optical properties of a diamond nanocrystal hosting a single nitrogen vacancy
center. We find that the nitrogen vacancy center is a sensitive probe of the
surrounding electromagnetic mode structure. We exploit this sensitivity to
demonstrate nanoscale fluorescence lifetime imaging microscopy (FLIM) with a
single nitrogen vacancy center by imaging the local density of states of an
optical antenna.


title: Multivariable Feedback Particle Filter

abstract:
  In recent work it is shown that importance sampling can be avoided in the
particle filter through an innovation structure inspired by traditional
nonlinear filtering combined with Mean-Field Game formalisms. The resulting
feedback particle filter (FPF) offers significant variance improvements; in
particular, the algorithm can be applied to systems that are not stable. The
filter comes with an up-front computational cost to obtain the filter gain.
This paper describes new representations and algorithms to compute the gain in
the general multivariable setting. The main contributions are, (i) Theory
surrounding the FPF is improved: Consistency is established in the multivariate
setting, as well as well-posedness of the associated PDE to obtain the filter
gain. (ii) The gain can be expressed as the gradient of a function, which is
precisely the solution to Poisson's equation for a related MCMC diffusion (the
Smoluchowski equation). This provides a bridge to MCMC as well as to
approximate optimal filtering approaches such as TD-learning, which can in turn
be used to approximate the gain. (iii) Motivated by a weak formulation of
Poisson's equation, a Galerkin finite-element algorithm is proposed for
approximation of the gain. Its performance is illustrated in numerical
experiments.


title:
Fission of actinides and superheavy nuclei: covariant density functional
  theory perspective

abstract:
  The current status of the application of covariant density functional theory
to the description of fission barriers in actinides and superheavy nuclei is
reviewed. The achievements and open problems are discussed.


title:
Gate defined wires in HgTe quantum wells: from Majorana fermions to
  spintronics

abstract:
  We introduce a promising new platform for Majorana zero-modes and various
spintronics applications based on gate-defined wires in HgTe quantum wells. Due
to the Dirac-like band structure for HgTe the physics of such systems differs
markedly from that of conventional quantum wires. Most strikingly, we show that
the subband parameters for gate-defined HgTe wires exhibit exquisite
tunability: modest gate voltage variation allows one to modulate the Rashba
spin-orbit energies from zero up to ~30K, and the effective g-factors from zero
up to giant values exceeding 600. The large achievable spin-orbit coupling and
g-factors together allow one to access Majorana modes in this setting at
exceptionally low magnetic fields while maintaining robustness against
disorder. As an additional benefit, gate-defined wires (in HgTe or other
settings) should greatly facilitate the fabrication of networks for refined
transport experiments used to detect Majoranas, as well as the realization of
non-Abelian statistics and quantum information devices.


title:
Classification with Asymmetric Label Noise: Consistency and Maximal
  Denoising

abstract:
  In many real-world classification problems, the labels of training examples
are randomly corrupted. Most previous theoretical work on classification with
label noise assumes that the two classes are separable, that the label noise is
independent of the true class label, or that the noise proportions for each
class are known. In this work, we give conditions that are necessary and
sufficient for the true class-conditional distributions to be identifiable.
These conditions are weaker than those analyzed previously, and allow for the
classes to be nonseparable and the noise levels to be asymmetric and unknown.
The conditions essentially state that a majority of the observed labels are
correct and that the true class-conditional distributions are "mutually
irreducible," a concept we introduce that limits the similarity of the two
distributions. For any label noise problem, there is a unique pair of true
class-conditional distributions satisfying the proposed conditions, and we
argue that this pair corresponds in a certain sense to maximal denoising of the
observed distributions.
  Our results are facilitated by a connection to "mixture proportion
estimation," which is the problem of estimating the maximal proportion of one
distribution that is present in another. We establish a novel rate of
convergence result for mixture proportion estimation, and apply this to obtain
consistency of a discrimination rule based on surrogate loss minimization.
Experimental results on benchmark data and a nuclear particle classification
problem demonstrate the efficacy of our approach.


title: Sample-Optimal Average-Case Sparse Fourier Transform in Two Dimensions

abstract:
  We present the first sample-optimal sublinear time algorithms for the sparse
Discrete Fourier Transform over a two-dimensional sqrt{n} x sqrt{n} grid. Our
algorithms are analyzed for /average case/ signals. For signals whose spectrum
is exactly sparse, our algorithms use O(k) samples and run in O(k log k) time,
where k is the expected sparsity of the signal. For signals whose spectrum is
approximately sparse, our algorithm uses O(k log n) samples and runs in O(k
log^2 n) time; the latter algorithm works for k=Theta(sqrt{n}). The number of
samples used by our algorithms matches the known lower bounds for the
respective signal models.
  By a known reduction, our algorithms give similar results for the
one-dimensional sparse Discrete Fourier Transform when n is a power of a small
composite number (e.g., n = 6^t).


title: The complex nature of the nuclear star cluster in FCC 277

abstract:
  Recent observations have shown that compact nuclear star clusters (NSCs) are
present in up to 80% of galaxies. However, detailed studies of their dynamical
and chemical properties are confined mainly to spiral galaxy hosts, where they
are more easily observed. In this paper we present our study of the NSC in FCC
277, a nucleated elliptical galaxy in the Fornax cluster. We use a combination
of adaptive optics assisted near-infrared integral field spectroscopy, Hubble
Space Telescope imaging, and literature long slit data. We show that while the
NSC does not appear to rotate within our detection limit of ~6 km/s, rotation
is detected at larger radii, where the isophotes appear to be disky, suggesting
the presence of a nuclear disk. We also observe a distinct central velocity
dispersion drop that is indicative of a dynamically cold rotating sub-system.
Following the results of orbit-based dynamical modelling, co-rotating as well
as counter-rotating stellar orbits are simultaneously needed to reproduce the
observed kinematics. We find evidence for varying stellar populations, with the
NSC and nuclear disk hosting younger and more metal rich stars than the main
body of the galaxy. We argue that gas dissipation and some level of merging
have likely played an important role in the formation of the nucleus of this
intermediate-mass galaxy. This is in contrast to NSCs in low-mass early- type
galaxies, which may have been formed primarily through the infall of star
clusters.


title: Three Family SU(5) GUT and Inverted Neutrino Mass Hierarchy

abstract:
  Supersymmetric SU(5) GUT augmented with anomaly free U(1)_F flavor symmetry
is presented. Very economical field content and U(1)_F charge assignment are
obtained by specific construction. In particular, three families of 10+5*
chiral matter, along the SU(5) singlet states (some of which serve as right
handed neutrinos) are obtained. Appealing texture zero Yukawa matrices provide
natural understanding of hierarchies between charged fermion masses and
mixings. The model predicts inverted hierarchical neutrino mass scenario with
interesting implications.


title: Long's Vortex Revisited

abstract:
  The conical self-similar vortex solution of Long (1961) is reconsidered, with
a view toward understanding what, if any, relationship exists between Long's
solution and the more-recent similarity solutions of Mayer and Powell (1992),
which are a rotational-flow analogue of the Falkner-Skan boundary-layer flows,
describing a self-similar axisymmetric vortex embedded in an external stream
whose axial velocity varies as a power law in the axial (z) coordinate, with
phi=r/z^n being the radial similarity coordinate and n the core growth rate
parameter. We show that, when certain ostensible differences in the
formulations and radial scalings are properly accounted for, the Long and
Mayer-Powell flows in fact satisfy the same system of coupled ordinary
differential equations, subject to different kinds of outer-boundary
conditions, and with Long's equations a special case corresponding to conical
vortex core growth, n=1 with outer axial velocity field decelerating in a 1/z
fashion, which implies a severe adverse pressure gradient. For pressure
gradients this adverse Mayer and Powell were unable to find any
leading-edge-type vortex flow solutions which satisfy a basic physicality
criterion based on monotonicity of the total-pressure profile of the flow, and
it is shown that Long's solutions also violate this criterion, in an extreme
fashion. Despite their apparent nonphysicality, the fact that Long's solutions
fit into a more general similarity framework means that nonconical analogues of
these flows should exist. The far-field asymptotics of these generalized
solutions are derived and used as the basis for a hybrid spectral-numerical
solution of the generalized similarity equations, which reveal the existence of
solutions for more modestly adverse pressure gradients than those in Long's
case, and which do satisfy the above physicality criterion.


title: Optical counterparts of the nearest ultraluminous X-ray sources

abstract:
  We present a photometric survey of the optical counterparts of ultraluminous
X-ray sources (ULXs) observed with the Hubble Space Telescope in nearby (< 5
Mpc) galaxies. Of the 33 ULXs with Hubble & Chandra data, 9 have no visible
counterpart, placing limits on their M_V of ~ -4 to -9, enabling us to rule out
O-type companions in 4 cases. The refined positions of two ULXs place them in
the nucleus of their host galaxy. They are removed from our sample. Of the 22
remaining ULXs, 13 have one possible optical counterpart, while multiple are
visible within the error regions of other ULXs. By calculating the number of
chance coincidences, we estimate that 13 +/- 5 are the true counterparts. We
attempt to constrain the nature of the companions by fitting the SED and M_V to
obtain candidate spectral types. We can rule out O-type companions in 20 cases,
while we find that one ULX (NGC 253 ULX2) excludes all OB-type companions.
Fitting with X-ray irradiated models provides constraints on the donor star
mass and radius. For 7 ULXs, we are able to impose inclination-dependent upper
and/or lower limits on the black holes mass, if the extinction to the assumed
companion star is not larger than the Galactic column. These are NGC 55 ULX1,
NGC 253 ULX1, NGC 253 ULX2, NGC 253 XMM6, Ho IX X-1, IC342 X-1 & NGC 5204 X-1.
This suggests that 10 ULXs do not have O companions, while none of the 18
fitted rule out B-type companions.


title:
Joint Probabilistic Data Association-Feedback Particle Filter for
  Multiple Target Tracking Applications

abstract:
  This paper introduces a novel feedback-control based particle filter for the
solution of the filtering problem with data association uncertainty. The
particle filter is referred to as the joint probabilistic data
association-feedback particle filter (JPDA-FPF). The JPDA-FPF is based on the
feedback particle filter introduced in our earlier papers. The remarkable
conclusion of our paper is that the JPDA-FPF algorithm retains the innovation
error-based feedback structure of the feedback particle filter, even with data
association uncertainty in the general nonlinear case. The theoretical results
are illustrated with the aid of two numerical example problems drawn from
multiple target tracking applications.


title:
On the Global Regularity of a Helical-decimated Version of the 3D
  Navier-Stokes Equations

abstract:
  We study the global regularity, for all time and all initial data in
$H^{1/2}$, of a recently introduced decimated version of the incompressible 3D
Navier-Stokes (dNS) equations. The model is based on a projection of the
dynamical evolution of Navier-Stokes (NS) equations into the subspace where
helicity (the $L^2-$scalar product of velocity and vorticity) is sign-definite.
The presence of a second (beside energy) sign-definite inviscid conserved
quadratic quantity, which is equivalent to the $H^{1/2}-$Sobolev norm, allows
us to demonstrate global existence and uniqueness, of space-periodic solutions,
together with continuity with respect to the initial conditions, for this
decimated 3D model. This is achieved thanks to the establishment of two new
estimates, for this 3D model, which show that the $H^{1/2}$ and the time
average of the square of the $H^{3/2}$ norms of the velocity field remain
finite. Such two additional bounds are known, in the spirit of the work of H.
Fujita and T. Kato \cite{kato1,kato2}, to be sufficient for showing
well-posedness for the 3D NS equations. Furthermore, they are directly linked
to the helicity evolution for the dNS model, and therefore with a clear
physical meaning and consequences.


title: Hodge theory for elliptic complexes over unital Banach $C^*$-algebras

abstract:
  We introduce a notion of ellipticity of complexes of linear
pseudodifferential operators acting on sections of $A$-Hilbert bundles over
smooth manifolds, $A$ being a Banach $C^*$-algebra. We prove that the
cohomology groups of an $A$-elliptic pseudodifferential complex in finitely
generated projective $A$-Hilbert bundles over a compact manifold are norm
complete finitely generated $A$-modules if the images of the associated
Laplacians are closed. This establishes a Hodge theory for these structures.


title:
Impulsive Noise Mitigation in Powerline Communications Using Sparse
  Bayesian Learning

abstract:
  Additive asynchronous and cyclostationary impulsive noise limits
communication performance in OFDM powerline communication (PLC) systems.
Conventional OFDM receivers assume additive white Gaussian noise and hence
experience degradation in communication performance in impulsive noise.
Alternate designs assume a parametric statistical model of impulsive noise and
use the model parameters in mitigating impulsive noise. These receivers require
overhead in training and parameter estimation, and degrade due to model and
parameter mismatch, especially in highly dynamic environments. In this paper,
we model impulsive noise as a sparse vector in the time domain without any
other assumptions, and apply sparse Bayesian learning methods for estimation
and mitigation without training. We propose three iterative algorithms with
different complexity vs. performance trade-offs: (1) we utilize the noise
projection onto null and pilot tones to estimate and subtract the noise
impulses; (2) we add the information in the data tones to perform joint noise
estimation and OFDM detection; (3) we embed our algorithm into a decision
feedback structure to further enhance the performance of coded systems. When
compared to conventional OFDM PLC receivers, the proposed receivers achieve SNR
gains of up to 9 dB in coded and 10 dB in uncoded systems in the presence of
impulsive noise.


title:
Solar magnetic activity cycles, coronal potential field models and
  eruption rates

abstract:
  We study the evolution of the observed photospheric magnetic field and the
modeled global coronal magnetic field during the past 3 1/2 solar activity
cycles observed since the mid-1970s. We use synoptic magnetograms and
extrapolated potential-field models based on longitudinal full-disk
photospheric magnetograms from the NSO's three magnetographs at Kitt Peak, the
Synoptic Optical Long-term Investigations of the Sun (SOLIS) vector
spectro-magnetograph (VSM), the spectro-magnetograph and the 512-channel
magnetograph instruments, and from the U. Stanford's Wilcox Solar Observatory.
The associated multipole field components are used to study the dominant length
scales and symmetries of the coronal field. Polar field changes are found to be
well correlated with active fields over most of the period studied, except
between 2003-6 when the active fields did not produce significant polar field
changes. Of the axisymmetric multipoles, only the dipole and octupole follow
the poles whereas the higher orders follow the activity cycle. All
non-axisymmetric multipole strengths are well correlated with the activity
cycle. The tilt of the solar dipole is therefore almost entirely due to
active-region fields. The axial dipole and octupole are the largest
contributors to the global field except while the polar fields are reversing.
This influence of the polar fields extends to modulating eruption rates.
According to the Computer Aided CME Tracking (CACTus), Solar Eruptive Event
Detection System (SEEDS), and Nobeyama radioheliograph prominence eruption
catalogs, the rate of solar eruptions is found to be systematically higher for
active years between 2003-2012 than for those between 1997-2002. This behavior
appears to be connected with the weakness of the late-cycle 23 polar fields as
suggested by Luhmann. We see evidence that the process of cycle 24 field
reversal is well advanced at both poles.


title:
Analysis of Partially Observed Networks via Exponential-family Random
  Network Models

abstract:
  Exponential-family random network (ERN) models specify a joint representation
of both the dyads of a network and nodal characteristics. This class of models
allow the nodal characteristics to be modelled as stochastic processes,
expanding the range and realism of exponential-family approaches to network
modelling. In this paper we develop a theory of inference for ERN models when
only part of the network is observed, as well as specific methodology for
missing data, including non-ignorable mechanisms for network-based sampling
designs and for latent class models. In particular, we consider data collected
via contact tracing, of considerable importance to infectious disease
epidemiology and public health.


title:
Reduced-Rank DOA Estimation based on Joint Iterative Subspace
  Optimization and Grid Search

abstract:
  In this paper, we propose a novel reduced-rank algorithm for direction of
arrival (DOA) estimation based on the minimum variance (MV) power spectral
evaluation. It is suitable to DOA estimation with large arrays and can be
applied to arbitrary array geometries. The proposed DOA estimation algorithm is
formulated as a joint optimization of a subspace projection matrix and an
auxiliary reduced-rank parameter vector with respect to the MV and grid search.
A constrained least squares method is employed to solve this joint optimization
problem for the output power over the grid. The proposed algorithm is described
for problems of large number of users' direction finding with or without exact
information of the number of sources, and does not require the singular value
decomposition (SVD). The spatial smoothing (SS) technique is also employed in
the proposed algorithm for dealing with correlated sources problem. Simulations
are conducted with comparisons against existent algorithms to show the improved
performance of the proposed algorithm in different scenarios.


title: Galileon bounce after ekpyrotic contraction

abstract:
  We consider a simple cosmological model that includes a long ekpyrotic
contraction stage and smooth bounce after it. Ekpyrotic behavior is due to a
scalar field with a negative exponential potential, whereas the Galileon field
produces bounce. We give an analytical picture of how the bounce occurs within
the weak gravity regime, and then perform numerical analysis to extend our
results to a non-perturbative regime.


title:
Measuring Detailed Chemical Abundances From Co-added Medium Resolution
  Spectra I. Tests using Milky Way dwarf spheroidal galaxies and globular
  clusters

abstract:
  The ability to measure metallicities and {\alpha}-element abundances in
individual red giant branch (RGB) stars using medium-resolution spectra ($R
\approx 6000$) is a valuable tool for deciphering the nature of Milky Way dwarf
satellites and the history of the Galactic halo. Extending such studies to more
distant systems like Andromeda is beyond the ability of the current generation
of telescopes, but by co-adding the spectra of similar stars, we can attain the
necessary signal-to-noise ratio to make detailed abundance measurements. In
this paper, we present a method to determine metallicities and {\alpha}-element
abundances using the co-addition of medium resolution spectra. We test the
method of spectral co-addition using high-S/N spectra of more than 1300 RGB
stars from Milky Way globular clusters and dwarf spheroidal galaxies obtained
with the Keck II telescope/DEIMOS spectrograph. We group similar stars using
photometric criteria and compare the weighted ensemble average abundances
([Fe/H], [Mg/Fe], [Si/Fe], [Ca/Fe] and [Ti/Fe]) of individual stars in each
group with the measurements made on the corresponding co-added spectrum. We
find a high level of agreement between the two methods, which permits us to
apply this co-added spectra technique to more distant RGB stars, like stars in
the M31 satellite galaxies. This paper outlines our spectral co-addition and
abundance measurement methodology and describes the potential biases in making
these measurements.


title:
Description of the superconducting state in the high-pressure fcc phase
  of platinum-hydride

abstract:
  The thermodynamic parameters of the superconducting state in PtH at the
pressure 76 GPa have been examined. The calculations have been carried out in
the framework of the Eliashberg formalism. It has been found that the critical
temperature changes in the range from 30.6 K to 16.8 K, depending on the
assumed value of the Coulomb pseudopotential (0.1, 0.2 and 0.3). The other
thermodynamic quantities differ significantly from the predictions of the
classical BCS theory. In particular: (i) The parameter which corresponds to the
superconducting band gap reaches the values from 4.25 to 3.98. (ii) The ratio
of the specific heat jump to the specific heat in the normal state takes the
values from 2.07 to 1.97. (iii) Finally, the parameter for the low-temperature
thermodynamic critical field is in the range from 0.145 to 0.156.


title: High contrast homogenisation in nonlinear elasticity under small loads

abstract:
  We study the homogenisation of geometrically nonlinear elastic composites
with high contrast. The composites we analyse consist of a perforated matrix
material, which we call the "stiff" material, and a "soft" material that fills
the pores. We assume that the pores are of size $0<\varepsilon\ll 1$ and are
periodically distributed with period $\varepsilon$. We also assume that the
stiffness of the soft material degenerates with rate $\varepsilon^{2\gamma},$
$\gamma>0$, so that the contrast between the two materials becomes infinite as
$\varepsilon\to 0$. We study the homogenisation limit $\varepsilon\to 0$ in a
low energy regime, where the displacement of the stiff component is
infinitesimally small. We derive an effective two-scale model, which, depending
on the scaling of the energy, is either a quadratic functional or a partially
quadratic functional that still allows for large strains in the soft
inclusions. In the latter case, averaging out the small scale-term justifies a
single-scale model for high-contrast materials, which features a non-linear and
non-monotone effect describing a coupling between microscopic and the effective
macroscopic displacements.


title:
Spectral analysis of one-dimensional high-contrast elliptic problems
  with periodic coefficients

abstract:
  We study the behaviour of the spectrum of a family of one-dimensional
operators with periodic high-contrast coefficients as the period goes to zero,
which may represent e.g. the elastic or electromagnetic response of a
two-component composite medium. Compared to the standard operators with
moderate contrast, they exhibit a number of new effects due to the underlying
non-uniform ellipticity of the family. The effective behaviour of such media in
the vanishing period limit also differs notably from that of multi-dimensional
models investigated thus far by other authors, due to the fact that neither
component of the composite forms a connected set. We then discuss a modified
problem, where the equation coefficient is set to a positive constant on an
interval that is independent of the period. Formal asymptotic analysis and
numerical tests with finite elements suggest the existence of localised
eigenfunctions ("defect modes"), whose eigenvalues situated in the gaps of the
limit spectrum for the unperturbed problem.


title: The Progression of Star Formation in the Rosette Molecular Cloud

abstract:
  Using Spitzer Space Telescope and Chandra X-ray Observatory data, we identify
YSOs in the Rosette Molecular Cloud (RMC). By being able to select cluster
members and classify them into YSO types, we are able to track the progression
of star formation locally within the cluster environments and globally within
the cloud. We employ nearest neighbor method (NNM) analysis to explore the
density structure of the clusters and YSO ratio mapping to study age
progressions in the cloud. We find a relationship between the YSO ratios and
extinction which suggests star formation occurs preferentially in the densest
parts of the cloud and that the column density of gas rapidly decreases as the
region evolves. This suggests rapid removal of gas may account for the low star
formation efficiencies observed in molecular clouds. We find that the overall
age spread across the RMC is small. Our analysis suggests that star formation
started throughout the complex around the same time. Age gradients in the cloud
appear to be localized and any effect the HII region has on the star formation
history is secondary to that of the primordial collapse of the cloud.


title:
Fast Diffusion of Magnetic Field in Turbulence and Origin of Cosmic
  Magnetism

abstract:
  Turbulence is believed to play important roles in the origin of cosmic
magnetism. While it is well known that turbulence can efficiently amplify a
uniform or spatially homogeneous seed magnetic field, it is not clear whether
or not we can draw a similar conclusion for a localized seed magnetic field.
The main uncertainty is the rate of magnetic field diffusion on scales larger
than the outer scale of turbulence. To measure the diffusion rate of magnetic
field on those large scales, we perform a numerical simulation in which the
outer scale of turbulence is much smaller than the size of the system. We
numerically compare diffusion of a localized seed magnetic field and a
localized passive scalar. We find that diffusion of the magnetic field can be
much faster than that of the passive scalar and that turbulence can efficiently
amplify the localized seed magnetic field. Based on the simulation result, we
construct a model for fast diffusion of magnetic field. Our model suggests that
a localized seed magnetic field can fill the whole system in (L_sys/L) times
the large-eddy turnover time and that growth of the magnetic field stops in
max(15, L_sys/L) times the large-eddy turnover time, where L_sys is the size of
the system and $L$ is the driving scale. Our finding implies that, regardless
of the shape of the seed field, fast magnetization is possible in turbulent
systems, such as large-scale structure of the universe or galaxies.


title:
Evolution Of Post-Impact Remnant Helium Stars In Type Ia Supernova
  Remnants Within The Single-Degenerate Scenario

abstract:
  The progenitor systems of Type Ia supernovae (SNe Ia) are still under debate.
Based on recent hydrodynamics simulations, non-degenerate companions in the
single-degenerate scenario (SDS) should survive the supernova impact. One way
to distinguish between the SDS and the double-degenerate scenario is to search
for the post-impact remnant stars (PIRSs) in SN Ia remnants. Using a technique
that combines multi-dimensional hydrodynamics simulations with one-dimensional
stellar evolution simulations, we have examined the post-impact evolution of
helium-rich binary companions in the SDS. It is found that these helium-rich
PIRSs (He PIRSs) dramatically expand and evolve to a luminous phase ($L\sim
10^4 L_\odot$) about 10 years after a supernova explosion. Subsequently, they
contract and evolve to become hot blue-subdwarf-like (sdO-like) stars by
releasing gravitational energy, persisting as sdO-like stars for several
million years before evolving to the helium red-giant phase. We therefore
predict that a luminous OB-like star should be detectable within $\sim 30$
years after the SN explosion. Thereafter, it will shrink and become an sdO-like
star in the central regions of SN Ia remnants within star-forming regions for
SN Ia progenitors evolved via the helium-star channel in the SDS. These He
PIRSs are predicted to be rapidly rotating ($v_{\rm rot} \gtrsim 50$ km
s$^{-1}$) and to have high spatial velocities ($v_{\rm linear} \gtrsim 500$ km
s$^{-1}$). Furthermore, if supernova remnants have diffused away and are not
recognizable at a later stage, He PIRSs could be an additional source of single
sdO stars and/or hypervelocity stars.


title: Ratios of partition functions for the log-gamma polymer

abstract:
  We introduce a random walk in random environment associated to an underlying
directed polymer model in $1+1$ dimensions. This walk is the positive
temperature counterpart of the competition interface of percolation and arises
as the limit of quenched polymer measures. We prove this limit for the exactly
solvable log-gamma polymer, as a consequence of almost sure limits of ratios of
partition functions. These limits of ratios give the Busemann functions of the
log-gamma polymer, and furnish centered cocycles that solve a variational
formula for the limiting free energy. Limits of ratios of point-to-point and
point-to-line partition functions manifest a duality between tilt and velocity
that comes from quenched large deviations under polymer measures. In the
log-gamma case, we identify a family of ergodic invariant distributions for the
random walk in random environment.


title:
Dipole-dipole interactions in optical lattices do not follow an inverse
  cube power law

abstract:
  We study the effective dipole-dipole interactions in ultracold quantum gases
on optical lattices as a function of asymmetry in confinement along the
principal axes of the lattice. In particular, we study the matrix elements of
the dipole-dipole interaction in the basis of lowest band Wannier functions
which serve as a set of low-energy states for many-body physics on the lattice.
We demonstrate that the effective interaction between dipoles in an optical
lattice is non-algebraic in the inter-particle separation at short to medium
distance on the lattice scale and has a long-range power-law tail, in contrast
to the pure power-law behavior of the dipole-dipole interaction in free space.
The modifications to the free-space interaction can be sizable; we identify
differences of up to 36% from the free-space interaction at the
nearest-neighbor distance in quasi-1D arrangements. The interaction difference
depends essentially on asymmetry in confinement, due to the d-wave anisotropy
of the dipole-dipole interaction. Our results do not depend on statistics,
applying to both dipolar Bose-Einstein condensates and degenerate Fermi gases.
Using matrix product state simulations, we demonstrate that use of the correct
lattice dipolar interaction leads to significant deviations from many-body
predictions using the free-space interaction. Our results are relevant to up
and coming experiments with ultracold heteronuclear molecules, Rydberg atoms,
and strongly magnetic atoms in optical lattices.


title:
Baryon-antibaryon production asymmetry in relativistic heavy ion
  collisions

abstract:
  Experimental data at RHIC and SPS energies suggest a systematic correlation
between yield ratio $\bar{p}/p$ and $K^{-}/K^{+}$, which reveal some
universality of hadron production in relativistic heavy ion collisions. We
propose an explanation based on the quark combination mechanism in which the
production asymmetry between baryons and antibaryons is focused on especially.
We start from the basic ideas of quark combination to carry out a general
analysis of the properties of the global production of baryons and mesons and
obtain the yields of baryons, antibaryons and mesons as functions of the number
of constituent quarks and antiquarks just before hadronization. In particular,
we study effects of quark-antiquark asymmetry on the ratio of (anti-)baryons to
mesons and that of antibaryons to baryons. We use these formula to well explain
the data of $\bar{p}/p$ and $K^{-}/K^{+}$ at different of collision energies
and rapidities and suggest further measurements at moderate RHIC energies in
the mid-forward rapidity regions to make the decisive test of this
universality.


title: Japanese-Spanish Thesaurus Construction Using English as a Pivot

abstract:
  We present the results of research with the goal of automatically creating a
multilingual thesaurus based on the freely available resources of Wikipedia and
WordNet. Our goal is to increase resources for natural language processing
tasks such as machine translation targeting the Japanese-Spanish language pair.
Given the scarcity of resources, we use existing English resources as a pivot
for creating a trilingual Japanese-Spanish-English thesaurus. Our approach
consists of extracting the translation tuples from Wikipedia, disambiguating
them by mapping them to WordNet word senses. We present results comparing two
methods of disambiguation, the first using VSM on Wikipedia article texts and
WordNet definitions, and the second using categorical information extracted
from Wikipedia, We find that mixing the two methods produces favorable results.
Using the proposed method, we have constructed a multilingual
Spanish-Japanese-English thesaurus consisting of 25,375 entries. The same
method can be applied to any pair of languages that are linked to English in
Wikipedia.


title: A quantum dynamical framework for Brownian heat engines

abstract:
  We present a self contained formalism modelled after the Brownian motion of a
quantum harmonic oscillator for describing the performance of microscopic
Brownian heat engines like Carnot, Stirling and Otto engines. Our theory,
besides reproducing the standard thermodynamics results in the steady state
enables permits us to study the role dissipation plays in determining the
efficiency of Brownian heat engines under actual laboratory conditions. In
particular, we analyse in detail the dynamics associated with decoupling a
system in equilibrium with one bath and recoupling it to another bath and
obtain exact analytical results which are shown to have significant
ramifications on the efficiencies of engines involving such a step. We also
develop a simple yet powerful technique for computing corrections to the steady
state results arising from finite operation time and use it to arrive at the
thermodynamic complementarity relations for various operating conditions and
also to compute the efficiencies of the three engines cited above at maximum
power. Some of the methods and techniques and exactly solvable models presented
here are interesting in their own right and, in our opinion, would find useful
applications in other contexts as well.


title: Long range interactions between alkali and alkaline-earth atoms

abstract:
  Dispersion coefficients between the alkali metal atoms (Li-Rb) and
alkaline-earth metal atoms (Be-Sr) are evaluated using matrix elements computed
from frozen core configuration interaction calculations. Besides dispersion
coefficients with both atoms in their respective ground states, dispersion
coefficients are also given for the case where one atom is in its ground state
and the other atom is in a low lying excited state.


title: Li$_2$RhO$_3$: A spin-glassy relativistic Mott insulator

abstract:
  Motivated by the rich interplay among electronic correlation, spin-orbit
coupling (SOC), crystal-field splitting, and geometric frustrations in the
honeycomb-like lattice, we systematically investigated the electronic and
magnetic properties of Li$_2$RhO$_3$. The material is semiconducting with a
narrow band gap of $\Delta\sim$78 meV, and its temperature dependence of
resistivity conforms to 3D variable range hopping mechanism. No long-range
magnetic ordering was found down to 0.5 K, due to the geometric frustrations.
Instead, single atomic spin-glass behavior below the spin-freezing temperature
($\sim$6 K) was observed and its spin dynamics obeys the universal critical
slowing down scaling law. First principle calculations suggested it to be a
relativistic Mott insulator mediated by both electronic correlation and SOC.
With moderate strength of electronic correlation and SOC, our results shed new
light to the research of Heisenberg-Kitaev model in realistic materials.


title: The Kinematics and Ionization of Nuclear Gas Clouds in Centaurus A

abstract:
  Neumayer et al. established the existence of a blue-shifted cloud in the core
of Centaurus A, within a few parsecs of the nucleus and close to the radio jet.
We propose that the cloud has been impacted by the jet, and that it is in the
foreground of the jet, accounting for its blue-shifted emission on the Southern
side of the nucleus. We consider both shock excitation and photoionization
models for the excitation of the cloud. Shock models do not account for the
[SiVI] and [CaVIII] emission line fluxes. However, X-ray observations indicate
a source of ionizing photons in the core of Centaurus A; photoionization by the
inferred flux incident on the cloud can account for the fluxes in these lines
relative to Brackett-gamma. The power-law slope of the ionizing continuum
matches that inferred from synchrotron models of the X-rays. The logarithm of
the ionization parameter is -1.9, typical of that in Seyfert galaxies and
consistent with the value proposed for dusty ionized plasmas. The model cloud
density depends upon the Lorentz factor of the blazar and the inclination of
our line of sight to the jet axis. For acute inclinations, the inferred density
is consistent with expected cloud densities. However, for moderate inclinations
of the jet to the line of sight, high Lorentz factors imply cloud densities in
excess of $10^5 cm^{-3}$ and very low filling factors, suggesting that models
of the gamma ray emission should incorporate jet Lorentz factors $\lesssim 5$.


title:
Analysis of a Kepler Light Curve of the Novalike Cataclysmic Variable
  KIC 8751494

abstract:
  We analyzed a Kepler light curve of KIC 8751494, a recently recognized
novalike cataclysmic variable in the Kepler field. We detected a stable
periodicity of 0.114379(1) d, which we identified as being the binary's orbital
period. The stronger photometric period around 0.12245 d, which had been
detected from the ground-based observation, was found to be variable, and we
identified this period as being the positive superhump period. This superhump
period showed short-term (10-20 d) and strong variations in period most
unexpectedly when the object entered a slightly faint state. The fractional
superhump excess varied as large as ~30%. The variation of the period very well
traced the variation of the brightness of the system. The time-scales of this
variation of the superhump period was too slow to be interpreted as the
variation caused by the change in the disk radius due to the thermal disk
instability. We interpreted that the period variation was caused by the varying
pressure effect on the period of positive superhumps. This finding suggests
that the pressure effect, in at least novalike systems, plays a very important
(up to ~30% in the precession rate) role in producing the period of the
positive superhumps. We also described a possible detection of the negative
superhumps with a varying period of 0.1071-0.1081 d in the Q14 run of the
Kepler data. We also found that the phase of the velocity variation of the
emission lines reported in the earlier study is compatible with the SW Sex-type
classification. Further, we introduced a new two-dimentional period analysis
using least absolute shrinkage and selection operator (Lasso) and showed
superior advantage of this method.


title: Toward the Integration of Traditional and Agile Approaches

abstract:
  The agile approach uses continuous delivery, instead of distinct procedure,
to work closer with customers and to respond faster requirement changes. All of
these are against the traditional plan driven approach. Due to agile method's
characteristics and its success in the real world practices, a number of
discussions regarding the differences between agile and traditional approaches
emerged recently and many studies intended to integrate both methods to
synthesize the benefits from these two sides. However, this type of research
often concludes from observations of a development activity or surveys after a
project. To provide a more objective supportive evidence of comparing these two
approaches, our research analyzes the source codes, logs, and notes. We argue
that the agile and traditional approaches share common characteristics, which
can be considered as the glue for integrating both methods. In our study, we
collect all the submissions from the version control repository, and meeting
notes and discussions. By applying our suggested analysis method, we illustrate
the shared properties between agile and traditional approaches; thus, different
development phases, like implementation and test, can still be identified in
agile development history. This result not only provides a positive result for
our hypothesis but also offers a suggestion for a better integration.


title: Higher K-theory of Koszul cubes

abstract:
  The main objective of this paper is to determine generators of the
topological filtrations on the higher K-theory of a noetherian commutative ring
with unit A. We introduce the concept of Koszul cubes and give a comparison
theorem between the K-theory of Koszul cubes with that of topological
filtrations.


title:
Generalized Dyson Brownian motion, McKean-Vlasov equation and
  eigenvalues of random matrices

abstract:
  Using It\^o's calculus and the mass optimal transportation theory, we study
the generalized Dyson Brownian motion (GDBM) and the associated McKean-Vlasov
evolution equation with an external potential $V$. Under suitable condition on
$V$, we prove the existence and uniqueness of strong solution to SDE for GDBM.
Standard argument shows that the family of the process of empirical measures
$L_N(t)$ of GDBM is tight and every accumulative point of $L_N(t)$ in the weak
convergence topology is a weak solution of the associated McKean-Vlasov
evolution equation, which can be realized as the gradient flow of the
Voiculescu free entropy on the Wasserstein space over $\mathbb{R}$. Under the
condition $V''\geq -K$ for some constant $K\geq 0$, we prove that the
McKean-Vlasov equation has a unique solution $\mu(t)$ and $L_N(t)$ converges
weakly to $\mu(t)$ as $N\rightarrow \infty$. For $C^2$ convex potentials, we
prove that $\mu(t)$ converges to the equilibrium measure $\mu_V$ with respect
to the $W_2$-Wasserstein distance on $\mathscr{P}_2(\mathbb{R})$ as
$t\rightarrow \infty$. Under the uniform convexity or a modified uniform
convexity condition on $V$, we prove that $\mu(t)$ converges to $\mu_V$ with
respect to the $W_2$-Wasserstein distance on $\mathscr{P}_2(\mathbb{R})$ with
an exponential rate as $t\rightarrow \infty$. Finally, we discuss the
double-well potentials and raise some conjectures.


title: The Ritz method with Lagrange multipliers

abstract:
  We develop a general form of the Ritz method for trial functions that do not
satisfy the essential boundary conditions. The idea is to treat the latter as
variational constraints and remove them using the Lagrange multipliers. In
multidimensional problems in addition to the trial functions boundary weight
functions also have to be selected to approximate the boundary conditions. We
prove convergence of the method and discuss its limitations and implementation
issues. In particular, we discuss the required regularity of the variational
functional, the completeness of systems of the trial functions, and conditions
for consistency of the equations for the trial solutions. The discussion is
accompanied by a detailed examination of examples, both analytic and numerical,
to illustrate the method.


title:
Hamilton's Harnack inequality and the $W$-entropy formula on complete
  Riemannian manifolds

abstract:
  In this paper, we prove Hamilton's Harnack inequality and the gradient
estimates of the logarithmic heat kernel for the Witten Laplacian on complete
Riemainnian manifolds. As applications, we prove the $W$-entropy formula for
the Witten Laplacian on complete Riemannian manifolds, and prove a family of
logarithmic Sobolev inequalities on complete Riemannian manifolds with natural
geometric condition.


title:
A Generalized Hybrid Real-Coded Quantum Evolutionary Algorithm Based on
  Particle Swarm Theory with Arithmetic Crossover

abstract:
  This paper proposes a generalized Hybrid Real-coded Quantum Evolutionary
Algorithm (HRCQEA) for optimizing complex functions as well as combinatorial
optimization. The main idea of HRCQEA is to devise a new technique for mutation
and crossover operators. Using the evolutionary equation of PSO a
Single-Multiple gene Mutation (SMM) is designed and the concept of Arithmetic
Crossover (AC) is used in the new Crossover operator. In HRCQEA, each triploid
chromosome represents a particle and the position of the particle is updated
using SMM and Quantum Rotation Gate (QRG), which can make the balance between
exploration and exploitation. Crossover is employed to expand the search space,
Hill Climbing Selection (HCS) and elitism help to accelerate the convergence
speed. Simulation results on Knapsack Problem and five benchmark complex
functions with high dimension show that HRCQEA performs better in terms of
ability to discover the global optimum and convergence speed.


title: Constraining models with a large scalar multiplet

abstract:
  Models in which the Higgs sector is extended by a single electroweak scalar
multiplet X can possess an accidental global U(1) symmetry at the
renormalizable level if X has isospin T greater or equal to 2. We show that all
such U(1)-symmetric models are excluded by the interplay of the cosmological
relic density of the lightest (neutral) component of X and its direct detection
cross section via Z exchange. The sole exception is the T=2 multiplet, whose
lightest member decays on a few-day to few-year timescale via a
Planck-suppressed dimension-5 operator.


title:
Quantized Conductance and Field-Effect Topological Quantum Transistor in
  Silicene Nanoribbons

abstract:
  Silicene (a monolayer of silicon atoms) is a quantum spin-Hall insulator,
which undergoes a topological phase transition into other insulators by
applying external field such as electric field, photo-irradiation and
antiferromagnetic order. We investigate the electronic and transport properties
of silicene nanoribbons based on the Landauer formalism. We propose to
determine topological phase transitions by measuring the density of states and
conductance. The conductance is quantized and changes its value when the system
transforms into different phases. We show that a silicene nanoribbon near the
zero energy acts as a field-effect transistor. This transistor is robust though
it makes use of the minimum quantized conductance since the zero-energy edge
states are topologically protected. Our findings open a new way to future
topological quantum devices.


title:
Diagnostics on the source properties of type II radio burst with
  spectral bumps

abstract:
  In recent studies (Feng et al., 2012; Kong et al., 2012), we proposed that
source properties of type II radio bursts can be inferred through a causal
relationship between the special shape of the type II dynamic spectrum (e.g.,
bump or break) and simultaneous extreme ultraviolet (EUV)/white light imaging
observations (e.g., CME-shock crossing streamer structures). As a further
extension of these studies, in this paper we examine the CME event dated on
December 31 2007 associated with a multiple type II radio burst. We identify
the presence of two spectral bump features on the observed dynamic spectrum. By
combining observational analyses of the radio spectral observations and the
EUV-white light imaging data, we conclude that the two spectral bumps are
resulted from CME-shock propagating across dense streamers on the southern and
northern sides of the CME, respectively. It is inferred that the corresponding
two type II emissions originate separately from the two CME-shock flanks where
the shock geometries are likely quasi-perpendicular or oblique. Since the
emission lanes are bumped as a whole within a relatively short time, it
suggests that the type IIs with bumps of the study are emitted from spatially
confined sources (with a projected lateral dimension smaller than 0.05-0.1
R$_\odot$ at a fundamental frequency level of 20-30 MHz).


title: Fuzzy Petri Nets for Human Behavior Verification and Validation

abstract:
  Regarding the rapid growth of the size and complexity of simulation
applications, designing applicable and affordable verification and validation
(V&V) structures is an important problem. On the other hand, nowadays human
behavior models are principles to make decision in many simulations and in
order to have valid decisions based on a reliable human decision model, first
the model must pass the validation and verification criteria. Usually human
behavior models are represented as fuzzy rule bases. In all the recent works,
V&V process is applied on a ready given rule-base. In this work, we are first
supposed to construct a fuzzy rule-base and then apply the V&V process on it.
Considering the professor-student interaction as the case-study, in order to
construct the rule base, a questionnaire is designed in a special way to be
transformed to a hierarchical fuzzy rule-base. The constructed fuzzy rule base
is then mapped to a fuzzy Petri net and then within the verification
(generating and searching the reachability graph) and validation (reasoning the
Petri net) process is searched for probable structural and semantic errors.


title: Investment and Consumption with Regime-Switching Discount Rates

abstract:
  This paper considers the problem of consumption and investment in a financial
market within a continuous time stochastic economy. The investor exhibits a
change in the discount rate. The investment opportunities are a stock and a
riskless account. The market coefficients and discount factor switch according
to a finite state Markov chain. The change in the discount rate leads to time
inconsistencies of the investor's decisions. The randomness in our model is
driven by a Brownian motion and a Markov chain. Following Ekeland and Pirvu we
introduce and characterize the subgame perfect strategies. Numerical
experiments show the effect of time preference on subgame perfect strategies
and the pre-commitment strategies.


title: Angle averages from B-factories

abstract:
  The most recent measurements of three CP violation angles of
Kobayashi-Maskawa unitarity triangle is reviewed.


title: A Quantum Approach of Meso-Magnet Dynamics with Spin Transfer Torque

abstract:
  We present a theory of magnetization dynamics driven by spin-polarized
current in terms of the quantum master equation. In the spin coherent state
representation, the master equation becomes a Fokker-Planck equation, which
naturally includes the spin transfer and quantum fluctuation. The current
electron scattering state is correlated to the magnet quantum states, giving
rise to quantum correction to the electron transport properties in the usual
semiclassical theory. In the large spin limit, the magnetization dynamics is
shown to obey the Hamilton-Jacobi equation or the Hamiltonian canonical
equations.


title:
A Multiwavelength Study of Eruptive Events on January 23, 2012
  Associated with a Major Solar Energetic Particle Event

abstract:
  We use multiwavelength data from space and ground based instruments to study
the solar flares and coronal mass ejections (CMEs) on January 23, 2012 that
were responsible for one of the largest solar energetic particle (SEP) events
of solar cycle 24. The eruptions consisting of two fast CMEs (1400 km/s and
2000 km/s) and M-class flares that occurred in active region 11402 located at
N28 W36. The two CMEs occurred in quick successions, so they interacted very
close to the Sun. The second CME caught up with the first one at a distance of
11-12 Rsun. The CME interaction may be responsible for the elevated SEP flux
and significant changes in the intensity profile of the SEP event. The compound
CME resulted in a double-dip moderate geomagnetic storm (Dst = -73 nT). The two
dips are due to the southward component of the interplanetary magnetic field in
the shock sheath and the ICME intervals. One possible reason for the lack of a
stronger geomagnetic storm may be that the ICME delivered a glancing blow to
Earth.


title:
A new ignition scheme using hybrid indirect-direct drive for inertial
  confinement fusion

abstract:
  A new hybrid indirect-direct-drive ignition scheme is proposed for inertial
confinement fusion: a cryogenic capsule encased in a hohlraum is first
compressed symmetrically by indirect-drive x-rays, and then accelerated and
ignited by both direct-drive lasers and x-rays. A steady high-density plateau
newly formed between the radiation and electron ablation fronts suppresses the
rarefaction at the radiation ablation front and greatly enhances the drive
pressure. Meanwhile, multiple shock reflections at the fuel/hot-spot interface
are prevented during capsule deceleration. Thus rapid ignition and burn are
realized. In comparison with the conventional indirect drive, the hybrid drive
implodes the capsule with a higher velocity ($\sim4.3\times10^7$ cm/s) and a
much lower convergence ratio ($\sim$25), and the growth of hydrodynamic
instabilities is significantly reduced, especially at the fuel/hot-spot
interface.


title: Diffuse PeV neutrino emission from Ultra-Luminous Infrared Galaxies

abstract:
  Ultra-luminous infrared galaxies (ULIRGs) are the most luminous and intense
starburst galaxies in the Universe. Both their star-formation rate (SFR) and
gas surface mass density are very high, implying a high supernovae rate and an
efficient energy conversion of energetic protons. A small fraction of these
supernovae is the so-called hypernovae with a typical kinetic energy ~1e52 erg
and a shock velocity >=1e9 cm/s. The strong shocks driven by hypernovae are
able to accelerate cosmic ray protons up to 1e17 eV. These energetic protons
lose a good fraction of their energy through proton-proton collision when
ejected into very dense interstellar medium, and as a result, produce high
energy neutrinos (<=5 PeV). Recent deep infrared surveys provide solid
constraints on the number density of ULIRGs across a wide redshift range
0<z<2.3, allowing us to derive the flux of diffuse neutrinos from hypernovae.
We find that at PeV energies, the diffuse neutrinos contributed by ULIRGs are
comparable with the atmosphere neutrinos with the flux of 2e-9GeV cm^-2/s/sr,
by assuming the injected cosmic ray power law spectrum with an index of -2.


title:
Statistics of general functions of a Gaussian field -application to
  non-Gaussianity from preheating-

abstract:
  We provide a general formula for calculating correlators of arbitrary
function of a Gaussian field. This work extends the standard leading-order
approximation based on the delta N formalism to the case where truncation of
the delta N at some low order does not yield the correct answer. As an
application of this formula, we investigate 2, 3 and 4-point functions of the
primordial curvature perturbation generated in the massless preheating model by
approximating the mapping between the curvature perturbation and the Gaussian
field as a sum of the many spiky normal distribution functions as suggested by
lattice calculations. We also discuss observational consequences of this case
and show that trispectrum would be a key observable to search signature of
preheating in the CMB map. It is found the forms of the curvature correlation
functions for any delta N, at the leading order in the correlator of the
Gaussian field, coincide with the standard local type ones. Within this
approximation, it is also found that the standard formula for the non-linearity
parameters given by the product of the derivatives of the e-folding number
still holds after we replace the bare e-folding number appearing in the
original delta N expansion with the one smoothed in the field space with a
Gaussian window function.


title:
Phase structure of 2-dimensional topological insulators by lattice
  strong coupling expansion

abstract:
  The phase structure of 2-dimensional topological insulators under a
sufficiently strong electron-electron interaction is investigated. The
effective theory is constructed by extending the idea of the Kane-Mele model on
the graphenelike honeycomb lattice, in terms of U(1) lattice gauge theory
(quantum electrodynamics, QED). We analyze the phase structure by the
techniques of strong coupling expansion of lattice gauge theory. As a result,
we find that the topological phase structure of the system is modified by the
electron-electron interaction. There evolves a new phase with the
antiferromagnetism not parallel to the direction pointed by the spin-orbit
coupling, in between the conventional and the topological insulator phases. We
also discuss the physical implication of the new phase structure found here, in
analogy to the parity-broken phase in lattice quantum chromodynamics (QCD),
known as "Aoki phase".

categories: cond-mat.str-el cond-mat.mes-hall hep-lat hep-ph


title:
Quantum Gravity Effects in Geodesic Motion and Predictions of
  Equivalence Principle Violation

abstract:
  We show that the Equivalence Principle (EP) is violated by Quantum Gravity
(QG) effects. The predicted violations are compared to experimental
observations for Gravitational Redshift, Law of Reciprocal Action and
Universality of Free Fall. This allows us to derive explicit bounds for
  $\beta$ - the QG scale.
  In our approach, there appears a deviation in the geodesic motion of a
particle. This deviation is induced by a non-commutative spacetime, consistent
with a Generalized Uncertainty Principle (GUP). GUP admits the presence of a
minimum length scale, that is advocated by QG theories. Remarkably, the GUP
induced corrections are quite robust since the bound on $\beta$ obtained by us,
{\it{in General Relativity scenario in an essentially classical setting}} of
modified geodesic motion, is closely comparable to similar bounds in recent
literature \cite{vag}. The latter are computed in purely {\it{quantum}} physics
domain in {\it{flat}} spacetime.


title:
Poincare inequality and exponential integrability of the hitting times
  of a Markov process

abstract:
  Extending the approach of the paper [Mathieu, P. (1997) Hitting times and
spectral gap inequalities, Ann. Inst. Henri Poincare 33, 4, 437 -- 465], we
prove that the Poincare inequality for a (possibly non-symmetric) Markov
process yields the exponential integrability of the hitting times of this
process. For symmetric elliptic diffusions, this provides a criterion for the
Poincare inequality in the terms of hitting times.


title:
Observation of TeV gamma-rays from the unidentified source HESS
  J1841-055 with the ARGO-YBJ experiment

abstract:
  We report the observation of a very high energy \gamma-ray source, whose
position is coincident with HESS J1841-055. This source has been observed for
4.5 years by the ARGO-YBJ experiment from November 2007 to July 2012. Its
emission is detected with a statistical significance of 5.3 standard
deviations. Parameterizing the source shape with a two-dimensional Gaussian
function we estimate an extension \sigma=(0.40(+0.32,-0.22}) degree, consistent
with the HESS measurement. The observed energy spectrum is dN/dE =(9.0-+1.6) x
10^{-13}(E/5 TeV)^{-2.32-+0.23} photons cm^{-2} s^{-1} TeV^{-1}, in the energy
range 0.9-50 TeV. The integral \gamma-ray flux above 1 TeV is 1.3-+0.4 Crab
units, which is 3.2-+1.0 times the flux derived by HESS. The differences in the
flux determination between HESS and ARGO-YBJ, and possible counterparts at
other wavelengths are discussed.


title: Integrable Flows for Starlike Curves in Centroaffine Space

abstract:
  We construct integrable hierarchies of flows for curves in centroaffine
${\mathbb R}^3$ through a natural pre-symplectic structure on the space of
closed unparametrized starlike curves. We show that the induced evolution
equations for the differential invariants are closely connected with the
Boussinesq hierarchy, and prove that the restricted hierarchy of flows on
curves that project to conics in ${\mathbb{RP}}^2$ induces the
Kaup-Kuperschmidt hierarchy at the curvature level.


title: On the Geometry of Null Cones to Infinity Under Curvature Flux Bounds

abstract:
  The main objective of this paper is to control the geometry of a future
outgoing truncated null cone extending smoothly toward infinity in an
Einstein-vacuum spacetime. In particular, we wish to do this under minimal
regularity assumptions, namely, at the (weighted) L^2-curvature level. We show
that if the curvature flux and the data on an initial sphere of the cone are
sufficiently close to the corresponding values in a standard Minkowski or
Schwarzschild null cone, then we can obtain quantitative bounds on the geometry
of the entire infinite cone. The same bounds also imply the existence of limits
at infinity of the natural geometric quantities. Furthermore, we make no global
assumptions on the spacetime, as all assumptions are applied only to this
single truncated cone. In our sequel paper, we will apply these results in
order to control the Bondi energy and the angular momentum associated with this
cone.


title:
Compton Scattering in Plasma: Multiple Scattering Effects and
  Application to Laser-Plasma Acceleration

abstract:
  We explore the physics of electron acceleration in a plasma medium in an
effective field theory framework. Employing a multiple Compton scattering
mechanism, it is found that the acceleration can be sustained in such a medium
so as to attain the energies up to the order of $O(100 \rm{MeV})$ within a
centimeter. Also, the collimation and mono-energetic electron spectrum can be
obtained by proper tuning of the plasma parameters with the photon frequency.
The present work is potentially useful in understanding the physics of
laser-plasma accelerators.


title: Resonance-like nuclear processes in solids: 3rd and 4th order processes

abstract:
  It is recognized that in the family of heavy charged particle and electron
assisted double nuclear processes resonance-like behavior can appear. The
transition rates of the heavy particle assisted 3rd-order and electron assisted
4th-order resonance like double nuclear processes are determined. The power of
low energy nuclear reactions in $Ni-H$ systems formed in $Ni$ placed in $H_{2}$
gas environment is treated. Nuclear power produced by quasi-resonant electron
assisted double nuclear processes in these $Ni-H$ systems is calculated. The
power obtained tallies with experiments and its magnitude is considerable for
practical applications.


title: A sufficient condition for $p$-valently harmonic functions

abstract:
  For normalized harmonic functions $f(z)=h(z)+\bar{g(z)}$ in the open unit
disk $\mathbb{U}$, a sufficient condition on $h(z)$ for $f(z)$ to be $p$-valent
in $\mathbb{U}$ is discussed. Moreover, some interesting examples and images of
$f(z)$ satisfying the obtained condition are enumerated.


title: Discovery of factors in matrices with grades

abstract:
  We present an approach to decomposition and factor analysis of matrices with
ordinal data. The matrix entries are grades to which objects represented by
rows satisfy attributes represented by columns, e.g. grades to which an image
is red, a product has a given feature, or a person performs well in a test. We
assume that the grades form a bounded scale equipped with certain aggregation
operators and conforms to the structure of a complete residuated lattice. We
present a greedy approximation algorithm for the problem of decomposition of
such matrix in a product of two matrices with grades under the restriction that
the number of factors be small. Our algorithm is based on a geometric insight
provided by a theorem identifying particular rectangular-shaped submatrices as
optimal factors for the decompositions. These factors correspond to formal
concepts of the input data and allow an easy interpretation of the
decomposition. We present illustrative examples and experimental evaluation.


title:
Monotonicity and 1-dimensional symmetry for solutions of an elliptic
  system arising in Bose-Einstein condensation

abstract:
  We study monotonicity and 1-dimensional symmetry for positive solutions with
algebraic growth of the following elliptic system: \[ \begin{cases} -\Delta u =
-u v^2 & \text{in $\R^N$}\\ -\Delta v= -u^2 v & \text{in $\R^N$}, \end{cases}
\] for every dimension $N \ge 2$. In particular, we prove a Gibbons-type
conjecture proposed by H. Berestycki, T. C. Lin, J. Wei and C. Zhao.


title: Long-term effect of inter-mode transitions in quantum Markovian process

abstract:
  We study the Markovian process of a multi-mode open system connecting with a
non-equilibrium environment, which consists of several heat baths with
different temperatures. As an illustration, we study the steady state of three
linearly coupled harmonic oscillators in long time evolution, two of which
contact with two independent bosonic heat baths with different temperatures
respectively. We show that the inter-mode transitions mediated by the
environment is responsible for the long time behaviour of the dynamics
evolution, which is usually considered to take effect only in short time
dynamics of the system immersed in a equilibrium heat bath with a single
temperature. In non-equilibrium systems, the ignorance of the inter-mode
transitions may give rise to some counter-intuitive result, thus they cannot be
neglected.


title:
Processes of $e^+e^- \to (\eta, \eta', \eta(1295), \eta(1475))\gamma$ in
  the extended Nambu -- Jona-Lasinio model

abstract:
  In the extended NJL model the total cross sections of the processes $e^+e^-
\to (\eta, \eta', \eta(1295), \eta(1405))\gamma$ at energies up to 2 GeV are
calculated. The intermediate vector mesons $\rho (770)$, $\omega(782)$, $\phi
(1020)$, $\rho' (1450)$, $\omega' (1420)$ and $\phi' (1680)$ are taken into
account. The latter three mesons are treated as the first radial excited
states. They are incorporated into the NJL model by means of polynomial form
factors. The calculation results are in satisfactory agreement with the
experimental data obtained with the SND detector at the VEPP-2M, Novosibirsk.
The predictions given for the process $e^+e^- \to (\eta',\eta(1295),
\eta(1405)) \gamma$ have not been experimentally tested yet.


title: Near threshold laser-modified proton emission in nuclear photoeffect

abstract:
  The change of the probability of proton emission in nuclear photoeffect due
to an intense coherent (laser) field is discussed near the threshold, where the
hindering effect of the Coulomb field of the remainder nucleus is essential.
The ratio of laser-assisted and laser free differential cross section is
deduced and found to be independent of the polarization state of the $\gamma $
field and the two types of initial nuclear state considered. The numerical
values of this ratio are given at some characteristic parameters of the intense
field.


title: Does "quantum nonlocality without entanglement" have quantum origin?

abstract:
  Quantum separable operations are defined as those that cannot produce
entanglement from separable states, and it is known that they strictly surpass
local operations and classical communication (LOCC) in a number of tasks, which
is sometimes referred to as "quantum nonlocality without entanglement." Here we
consider a task with such a gap regarding the trade-off between state
discrimination and preservation of entanglement. We show that this task along
with the gap has an analogue in a purely classical setup, indicating that the
quantum properties are not essential in the existence of a nonzero gap between
the separable operations and LOCC.


title:
Leading-order nucleon self-energy in relativistic chiral effective field
  theory

abstract:
  We apply thermal field theory methods to compute microscopically the nucleon
self-energy arising from one-pion exchange in isospin-symmetric nuclear matter
and neutron matter. A self-consistent numerical scheme is introduced and its
convergence is demonstrated. The repulsive contribution from the Fock exchange
diagram to the energy per nucleon in symmetric nuclear matter is obtained.


title: Convex and Scalable Weakly Labeled SVMs

abstract:
  In this paper, we study the problem of learning from weakly labeled data,
where labels of the training examples are incomplete. This includes, for
example, (i) semi-supervised learning where labels are partially known; (ii)
multi-instance learning where labels are implicitly known; and (iii) clustering
where labels are completely unknown. Unlike supervised learning, learning with
weak labels involves a difficult Mixed-Integer Programming (MIP) problem.
Therefore, it can suffer from poor scalability and may also get stuck in local
minimum. In this paper, we focus on SVMs and propose the WellSVM via a novel
label generation strategy. This leads to a convex relaxation of the original
MIP, which is at least as tight as existing convex Semi-Definite Programming
(SDP) relaxations. Moreover, the WellSVM can be solved via a sequence of SVM
subproblems that are much more scalable than previous convex SDP relaxations.
Experiments on three weakly labeled learning tasks, namely, (i) semi-supervised
learning; (ii) multi-instance learning for locating regions of interest in
content-based information retrieval; and (iii) clustering, clearly demonstrate
improved performance, and WellSVM is also readily applicable on large data
sets.


title: Non-connective K- and Nil-spectra of additive categorie

abstract:
  We present an elementary construction of the non-connective algebraic
K-theory spectrum associated to an additive category following the contracted
functor approach due to Bass. It comes with a universal property that easily
allows us to identify it with other constructions, for instance with the one of
Pedersen-Weibel in terms of Z^i-graded objects and bounded homomorphisms.


title:
Central Stellar Mass Deficits in the Bulges of Local Lenticular
  Galaxies, and the Connection with Compact z ~ 1.5 Galaxies

abstract:
  We have used the full radial extent of images from the Hubble Space
Telescope's Advanced Camera for Surveys and Wide Field Planetary Camera 2 to
extract surface brightness profiles from a sample of six, local lenticular
galaxy candidates. We have modelled these profiles using a core-Sersic bulge
plus an exponential disk model. Our lenticular disk galaxies with bulge
magnitudes M_V < ~ -21.30 mag have central stellar deficits, suggesting that
these bulges may have formed from `dry' merger events involving supermassive
black holes while their surrounding disk was subsequently built up, perhaps via
cold gas accretion scenarios. The central stellar mass deficits M_def are
roughly 0.5 to 2 M_BH (black hole mass), rather than ~ 10 to 20 M_BH as claimed
from some past studies, which is in accord with core-Sersic model mass deficit
measurements in elliptical galaxies. Furthermore, these bulges have Sersic
indices n ~ 3, half light radii R_e < 2 kpc and masses > 10^11 M_sun, and
therefore appear to be descendants of the compact galaxies reported at z ~ 1.5
to 2. Past studies which have searched for these local counterparts by using
single-component galaxy models to provide the z ~ 0 size comparisons have
over-looked these dense, compact and massive bulges in today's early-type disk
galaxies. This evolutionary scenario not only accounts for what are today
generally old bulges---which must be present in z ~ 1.5 images---residing in
what are generally young disks, but it eliminates the uncomfortable suggestion
of a factor of 3 to 5 growth in size for the compact, z ~ 1.5 galaxies that are
known to possess infant disks.


title: Charged shells and elementary particles

abstract:
  We review the General Relativistic model of a (quasi) point-like particle
represented by a massive shell of electrically charged matter, which displays
an ADM mass M equal to the electric charge |Q| in the small-volume limit. We
employ the Israel-Darboux's junction equations to explicitly derive this
result, and then study the modifications introduced by the existence of a
minimum length scale lambda. For lambda of the order of the Planck length (or
larger), we find that the ADM mass becomes equal to the bare mass m_0 of the
shell, like it occurs for the neutral case.


title: The APACHE Project

abstract:
  First, we summarize the four-year long efforts undertaken to build the final
setup of the APACHE Project, a photometric transit search for small-size
planets orbiting bright, low-mass M dwarfs. Next, we describe the present
status of the APACHE survey, officially started in July 2012 at the site of the
Astronomical Observatory of the Autonomous Region of the Aosta Valley, in the
Western Italian Alps. Finally, we briefly discuss the potentially far-reaching
consequences of a multi-technique characterization program of the (potentially
planet-bearing) APACHE targets.


title:
Nonlinear Surface Resistance of YBa2Cu3O7-x Superconducting Thin Films
  on MgO Substrates in Dielectric Resonator at Ultra High Frequencies

abstract:
  The nonlinear surface resistance Rs of the YBa2Cu3O7-x superconducting thin
films on the MgO substrates was researched in the Hakki-Coleman dielectric
resonator at the microwave signal powers from -18 dBm to +30 dBm at the ultra
high frequency of 25 GHz in the range of temperatures from 12 K to 85 K. The
dependences of the surface resistance on the temperature RS(T) in the
YBa2Cu3O7-x superconducting thin films at the microwaves were measured. The
dependence of the surface resistance on the microwave power RS(P) in the
YBa2Cu3O7-x superconducting thin films at the microwaves were found at the two
temperatures T = 25 K and T = 50 K. The full expression for the estimation of
the measurements accuracy of the surface resistance RS was derived, and the
measurements accuracy was set at 1 %. The physical mechanisms, which can be
used to explain the experimental results, were discussed. It is shown that the
surface resistance Rs can nonlinearly increase as a result of the transition by
the sub-surface layer of the HTS thin film in a mixed state with the Abricosov
and Josephson magnetic vortices generation at an increase of the microwave
signal power P above the magnitude of 8 dBm. It is assumed that some additional
energy losses have place, because of the microwave power dissipation on the
normal metal cores of the magnetic vortices.

categories: cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.supr-con nlin.CD physics.ins-det


title: Answers to some problems about graph coloring test graphs

abstract:
  We prove that a graph whose chromatic number is 2 is a homotopy test graph.
We also prove that there is a graph $K$ with two involutions $\gamma_1$ and
$\gamma_2$ such that $(K,\gamma_1)$ is a Stiefel-Whitney test graph, but
$(K,\gamma_2)$ is not. These are answers to some of the problems suggested by
Kozlov.


title: A "Gaussian" for diffusion on the sphere

abstract:
  We present an analytical closed form expression, which gives a good
approximate propagator for diffusion on the sphere. Our formula is the
spherical counterpart of the Gaussian propagator for diffusion on the plane.
While the analytical formula is derived using saddle point methods for short
times, it works well even for intermediate times. Our formula goes beyond
conventional "short time heat kernel expansions" in that it is nonperturbative
in the spatial coordinate, a feature that is ideal for studying large
deviations. Our work suggests a new and efficient algorithm for numerical
integration of the diffusion equation on a sphere. We perform Monte Carlo
simulations to compare the numerical efficiency of the new algorithm with the
older Gaussian one.