title: Dimerized Solids and Resonating Plaquette Order in SU(N)-Dirac Fermions

abstract:
  We study the quantum phases of fermions with an explicit SU(N)-symmetric,
Heisenberg-like nearest-neighbor flavor exchange interaction on the honeycomb
lattice at half-filling. Employing projective (zero temperature) quantum Monte
Carlo simulations for even values of N, we explore the evolution from a
weak-coupling semimetal into the strong-coupling, insulating regime.
Furthermore, we compare our numerical results to a saddle-point approximation
in the large-N limit. From the large-N regime down to the SU(6) case, the
insulating state is found to be a columnar valence bond crystal, with a direct
transition to the semimetal at weak, finite coupling, in agreement with the
mean-field result in the large-N limit. At SU(4) however, the insulator
exhibits a subtly different valence bond crystal structure, stabilized by
resonating valence bond plaquettes. In the SU(2) limit, our results support a
direct transition between the semimetal and an antiferromagnetic insulator.


title: The Submillimeter Polarization Spectrum of M17

abstract:
  We present 450 {\mu}m polarimetric observations of the M17 molecular cloud
obtained with the SHARP polarimeter at the Caltech Submillimeter Observatory.
Across the observed region, the magnetic field orientation is consistent with
previous submillimeter and far-infrared polarization measurements. Our
observations are centered on a region of the molecular cloud that has been
compressed by stellar winds from a cluster of OB stars. We have compared these
new data with previous 350 {\mu}m polarimetry and find an anti-correlation
between the 450 to 350 {\mu}m polarization magnitude ratio and the ratio of 21
cm to 450 {\mu}m intensity. The polarization ratio is lower near the east end
of the studied region where the cloud is exposed to stellar winds and
radiation. At the west end of the region, the polarization ratio is higher. We
interpret the varying polarization spectrum as evidence supporting the
radiative alignment torque (RAT) model for grain alignment, implying higher
alignment efficiency in the region that is exposed to a higher anisotropic
radiation field.


title:
Semilinearity and Context-Freeness of Languages Accepted by Valence
  Automata

abstract:
  Valence automata are a generalization of various models of automata with
storage. Here, each edge carries, in addition to an input word, an element of a
monoid. A computation is considered valid if multiplying the monoid elements on
the visited edges yields the identity element. By choosing suitable monoids, a
variety of automata models can be obtained as special valence automata.
  This work is concerned with the accepting power of valence automata.
Specifically, we ask for which monoids valence automata can accept only
context-free languages or only languages with semilinear Parikh image,
respectively.
  First, we present a characterization of those graph products (of monoids) for
which valence automata accept only context-free languages. Second, we provide a
necessary and sufficient condition for a graph product of copies of the
bicyclic monoid and the integers to yield only languages with semilinear Parikh
image when used as a storage mechanism in valence automata. Third, we show that
all languages accepted by valence automata over torsion groups have a
semilinear Parikh image.


title:
arXiv e-prints and the journal of record: An analysis of roles and
  relationships

abstract:
  Since its creation in 1991, arXiv has become central to the diffusion of
research in a number of fields. Combining data from the entirety of arXiv and
the Web of Science (WoS), this paper investigates (a) the proportion of papers
across all disciplines that are on arXiv and the proportion of arXiv papers
that are in the WoS, (b) elapsed time between arXiv submission and journal
publication, and (c) the aging characteristics and scientific impact of arXiv
e-prints and their published version. It shows that the proportion of WoS
papers found on arXiv varies across the specialties of physics and mathematics,
and that only a few specialties make extensive use of the repository. Elapsed
time between arXiv submission and journal publication has shortened but remains
longer in mathematics than in physics. In physics, mathematics, as well as in
astronomy and astrophysics, arXiv versions are cited more promptly and decay
faster than WoS papers. The arXiv versions of papers - both published and
unpublished - have lower citation rates than published papers, although there
is almost no difference in the impact of the arXiv versions of both published
and unpublished papers.


title: Internal Gravity Waves in Massive Stars: Angular Momentum Transport

abstract:
  We present numerical simulations of internal gravity waves (IGW) in a star
with a convective core and extended radiative envelope. We report on
amplitudes, spectra, dissipation and consequent angular momentum transport by
such waves. We find that these waves are generated efficiently and transport
angular momentum on short timescales over large distances. We show that, as in
the Earth's atmosphere, IGW drive equatorial flows which change magnitude and
direction on short timescales. These results have profound consequences for the
observational inferences of massive stars, as well as their long term angular
momentum evolution. We suggest IGW angular momentum transport may explain many
observational mysteries, such as: the misalignment of hot Jupiters around hot
stars, the Be class of stars, Ni enrichment anomalies in massive stars and the
non-synchronous orbits of interacting binaries.


title:
Emery vs. Hubbard model for cuprate superconductors: a Composite
  Operator Method study

abstract:
  Within the Composite Operator Method (COM), we report the solution of the
Emery model (also known as p-d or three band model), which is relevant for the
cuprate high-Tc superconduc- tors. We also discuss the relevance of the
often-neglected direct oxygen-oxygen hopping for a more accurate, sometimes
unique, description of this class of materials. The benchmark of the solution
is performed by comparing our results with the available quantum Monte Carlo
ones. Both single- particle and thermodynamic properties of the model are
studied in detail. Our solution features a metal-insulator transition at half
filling. The resulting metal-insulator phase diagram agrees qual- itatively
very well with the one obtained within Dynamical Mean-Field Theory. We discuss
the type of transition (Mott-Hubbard (MH) or charge-transfer (CT)) for the
microscopic (ab-initio) parameter range relevant for cuprates getting, as
expected a CT type. The emerging single-particle scenario clearly suggests a
very close relation between the relevant sub-bands of the three- (Emery) and
the single- band (Hubbard) models, thus providing an independent and
non-perturbative proof of the validity of the mapping between the two models
for the model parameters optimal to describe cuprates. Such a result confirms
the emergence of the Zhang-Rice scenario, which has been recently questioned.
We also report the behavior of the specific heat and of the entropy as
functions of the temperature on varying the model parameters as these
quantities, more than any other, depend on and, consequently, reveal the most
relevant energy scales of the system.


title: The Intrinsic Shape of Galaxies in SDSS/Galaxy Zoo

abstract:
  By modelling the axis ratio distribution of SDSS DR8 galaxies we find the
intrinsic 3D shapes of spirals and ellipticals. We use morphological
information from the Galaxy Zoo project and assume a non-parametric
distribution intrinsic of shapes, while taking into account dust extinction.
  We measure the dust extinction of the full sample of spiral galaxies and find
a smaller value than previous estimations, with an edge-on extinction of $E_0 =
0.284^{+0.015}_{-0.026}$ in the SDSS r band. We also find that the distribution
of minor to major axis ratio has a mean value of $ 0.267 \pm 0.009 $, slightly
larger than previous estimates mainly due to the lower extinction used; the
same affects the circularity of galactic discs, which are found to be less
round in shape than in previous studies, with a mean ellipticity of $0.215 \pm
0.013$.
  For elliptical galaxies, we find that the minor to major axis ratio, with a
mean value of $0.584 \pm 0.006$, is larger than previous estimations due to the
removal of spiral interlopers present in samples with morphological information
from photometric profiles. These interlopers are removed when selecting
ellipticals using Galaxy Zoo data.
  We find that the intrinsic shapes of galaxies and their dust extinction vary
with absolute magnitude, colour and physical size. We find that bright
elliptical galaxies are more spherical than faint ones, a trend that is also
present with galaxy size, and that there is no dependence of elliptical galaxy
shape with colour. For spiral galaxies we find that the reddest ones have
higher dust extinction as expected, due to the fact that this reddening is
mainly due to dust. We also find that the thickness of discs increases with
luminosity and size, and that brighter, smaller and redder galaxies have less
round discs.


title: Painleve Field Theory

abstract:
  We propose multidimensional versions of the Painlev\'e VI equation and its
degenerations. These field theories are related to the isomonodromy problems of
flat holomorphic infinite rank bundles over elliptic curves and take the form
of non-autonomous Hamiltonian equations. The modular parameter of curves plays
the role of "time". Reduction of the field equations to the zero modes leads to
${\rm SL}(N, {\mathbb C})$ monodromy preserving equations. The latter coincide
with the Painlev\'e VI equation for $N\!=\!2$. We consider two types of the
bundles. In the first one the group of automorphisms is the centrally and
cocentrally extended loop group $L({\rm SL}(N, {\mathbb C}))$ or some multiloop
group. In the case of the Painlev\'e VI field theory in D=1+1 four constants of
the Painlev\'e VI equation become dynamical fields. The second type of bundles
are defined by the group of automorphisms of the noncommutative torus. They
lead to the equations in dimension 2+1. In both cases we consider
trigonometric, rational and scaling limits of the theories. Generically (except
some degenerate cases) the derived equations are nonlocal. We consider Whitham
quasiclassical limit to integrable systems. In this way we derive two and three
dimensional integrable nonlocal versions of the integrable Euler-Arnold tops.


title: Water loss from terrestrial planets with CO2-rich atmospheres

abstract:
  Water photolysis and hydrogen loss from the upper atmospheres of terrestrial
planets is of fundamental importance to climate evolution but remains poorly
understood in general. Here we present a range of calculations we performed to
study the dependence of water loss rates from terrestrial planets on a range of
atmospheric and external parameters. We show that CO2 can only cause
significant water loss by increasing surface temperatures over a narrow range
of conditions, with cooling of the middle and upper atmosphere acting as a
bottleneck on escape in other circumstances. Around G-stars, efficient loss
only occurs on planets with intermediate CO2 atmospheric partial pressures (0.1
to 1 bar) that receive a net flux close to the critical runaway greenhouse
limit. Because G-star total luminosity increases with time but XUV/UV
luminosity decreases, this places strong limits on water loss for planets like
Earth. In contrast, for a CO2-rich early Venus, diffusion limits on water loss
are only important if clouds caused strong cooling, implying that scenarios
where the planet never had surface liquid water are indeed plausible. Around
M-stars, water loss is primarily a function of orbital distance, with planets
that absorb less flux than ~270 W/m^2 (global mean) unlikely to lose more than
one Earth ocean of H2O over their lifetimes unless they lose all their
atmospheric N2/CO2 early on. Because of the variability of H2O delivery during
accretion, our results suggest that many 'Earth-like' exoplanets in the
habitable zone may have ocean-covered surfaces, stable CO2/H2O-rich
atmospheres, and high mean surface temperatures.


title:
Oscillatory instability of fully 3D flow in a cubic diagonally
  lid-driven cavity

abstract:
  A transition to unsteadiness of a flow inside a cubic diagonally lid-driven
cavity with no-slip boundaries is numerically investigated by a series of
direct numerical simulations (DNS) performed on 100^3 and 200^3 stretched
grids. It is found that the observed oscillatory instability is setting in via
a subcritical symmetry-breaking Hopf bifurcation. The instability evolves on
two vortices in a coupled manner. Critical values of Reynolds number Recr=2320
and non-dimensional angular oscillating frequency omegacr=0.249 for transition
from steady to oscillatory flow are accurately estimated. Characteristic
patterns of the 3D oscillatory flow are presented.


title: Repulsive Interactions in Quantum Hall Systems as a Pairing Problem

abstract:
  A subtle relation between Quantum Hall physics and the phenomenon of pairing
is unveiled. By use of second quantization, we establish a connection between
(i) a broad class of rotationally symmetric two-body interactions within the
lowest Landau level and (ii) integrable hyperbolic Richardson-Gaudin type
Hamiltonians that arise in (p_{x}+ip_{y}) superconductivity. Specifically, we
show that general Haldane pseudopotentials (and their sums) can be expressed as
a sum of repulsive non-commuting (p_{x}+ip_{y})-type pairing Hamiltonians. For
the Laughlin sequence, it is observed that this problem is frustration free and
zero energy ground states lie in the common null space of all of these
non-commuting Hamiltonians. This property allows for the use of a new truncated
basis of pairing configurations in which to express Laughlin states at general
filling factors. We prove separability of arbitrary Haldane pseudopotentials,
providing explicit expressions for their second quantized forms, and further
show by explicit construction how to exploit the topological equivalence
between different geometries (disk, cylinder, and sphere) sharing the same
topological genus number, in the second quantized formalism, through similarity
transformations. As an application of the second quantized approach, we
establish a "squeezing principle" that applies to the zero modes of a general
class of Hamiltonians, which includes but is not limited to Haldane
pseudopotentials. We also show how one may establish (bounds on)
"incompressible filling factors" for those Hamiltonians. By invoking properties
of symmetric polynomials, we provide explicit second quantized quasi-hole
generators; the generators that we find directly relate to bosonic chiral edge
modes and further make aspects of dimensional reduction in the Quantum Hall
systems precise.

categories: cond-mat.str-el cond-mat.supr-con math-ph math.MP quant-ph


title:
Nuclear Polarization Corrections to mu-d Atoms in Zero-Range
  Approximation

abstract:
  Nuclear polarization corrections to the 2P-2S Lamb shift in mu-d atoms are
developed in order alpha^5 and are shown to agree with a recent calculation.
The nuclear physics in the resulting corrections is then evaluated in
zero-range approximation. The dominant part of the correction is very simple in
form and differs from a recent potential model calculation by less than 1%. It
is also demonstrated how the third-Zemach-moment contribution largely cancels
against part of the polarization correction, as it did in e-d atoms and does so
exactly for point-like nucleons. This suggests that it may be possible to
reduce the uncertainty in the theory (of which nuclear polarization is the
largest contributor) to less than 1%.


title: Interacting viscous dark fluids

abstract:
  We revise the conditions for the physical viability of a cosmological model
in which dark matter has bulk viscosity and also interacts with dark energy. We
have also included radiation and baryonic matter components; all matter
components are represented by perfect fluids, except the dark matter, that is
treated as an imperfect fluid. We impose upon the model the condition of a
complete cosmological dynamics that results in an either null or negative bulk
viscosity, but the latter also disagrees with the Local Second Law of
Thermodynamics. The model is also compared with cosmological observations at
different redshifts: type Ia supernova, the shift parameter of CMB, the
acoustic peak of BAO, and the Hubble parameter H(z). In general, observations
consistently point out to a negative value of the bulk viscous coefficient, and
in overall the fitting procedure shows no preference for the model over the
standard LCDM model.


title:
The calculation of prompt fission neutron spectrum for 233U(n,f)
  reaction by the semi-empirical method

abstract:
  The prompt fission neutron spectra for neutron-induced fission of 233U for
low energy neutrons (below 6 MeV) are calculated using the nuclear evaporation
theory with a semi-empirical method, in which the partition of the total
excitation energy between the fission fragments for the nth+233U fission
reactions are determined with the available experimental and evaluation data.
The calculated prompt fission neutron spectra agree well with the experimental
data. The proportions of high- energy outgoing neutrons of prompt fission
neutron spectrum versus incident neutron energies are investigated with the
theoretical spectra, and the results are consistent with the systematics. We
conclude that the semi-empirical method is sound, and it could be a useful tool
for prompt fission neutron spectra evaluation.


title:
A method for evaluating the expectation value of a power spectrum using
  the probability density function of phases

abstract:
  Here, we present a new method to evaluate the expectation value of the power
spectrum of a time series. A statistical approach is adopted to define the
method. After its demonstration, it is validated showing that it leads to the
known properties of the power spectrum when the time series contains a periodic
signal. The approach is also validated in general with numerical simulations.
The method puts into evidence the importance that is played by the probability
density function of the phases associated to each time stamp for a given
frequency, and how this distribution can be perturbed by the uncertainties of
the parameters in the pulsar ephemeris. We applied this method to solve the
power spectrum in the case the first derivative of the pulsar frequency is
unknown and not negligible. We also undertook the study of the most general
case of a blind search, in which both the frequency and its first derivative
are uncertain. We found the analytical solutions of the above cases invoking
the sum of Fresnel's integrals squared.


title:
Performance of commercial CMOS cameras for high-speed multicolor
  photometry

abstract:
  We present some results of testing of commercial color CMOS cameras for
astronomical applications. CMOS sensors allow to perform photometry in three
filters simultaneously that gives a great advantage compared with monochrome
CCD detectors. The Bayer BGR colour system realized in CMOS sensors is close to
the Johnson BVR system. We demonstrate transformation from the Bayer color
system to the Johnson one. Our photometric measurements with color CMOS cameras
coupled to small telescopes (11 - 30 inch) reveal that in video mode stars up
to V $\sim$ 9 can be shot at 24 frames per second. Using a high-speed CMOS
camera with short exposure times (10 - 20 ms) we can perform an imaging mode
called "lucky imaging". We can pick out high quality frames and combine them
into a single image using "shift-and-add" technique. This allows us obtain an
image with much higher resolution than would be possible shooting a single
image with long exposure. For image selection we use the Strehl-selection
method. We demonstrates advantage of the lucky imaging technique in comparison
with long exposure shooting. The FWHM of the blurred image caused by atmosphere
turbulence can be decreased twice and more.


title:
The exit time of planar Brownian motion and the Phragmen-Lindelof
  principle

abstract:
  In this note, we prove a version of the Phragmen-Lindelof principle using
probabilistic techniques. In particular, we will show that if the p-th moment
of the exit time of Brownian motion from a planar domain is finite, then an
analytic function on that domain is either bounded by its supremum on the
boundary or else goes to infinity along some sequence more rapidly than
$e^{|z|^{2p}}$. We also present a method for constructing domains whose exit
time has finite p-th moment, thereby giving a general Phragmen-Lindelof
principle for spiral-like and star-like domains, and in the process giving a
probabilistic proof of a theorem of Hansen. A number of auxiliary results are
presented as well.


title: A slope conjecture for links

abstract:
  The slope conjecture gives a precise relation between the degree of the
colored Jones polynomial of a knot and the boundary slopes of essential
surfaces in the knot complement. In this note we propose a generalization of
the slope conjecture to links. We prove the conjecture for all alternating and
more generally adequate links. We also verify the conjecture for torus links.


title: Virtual neighborhood technique for pseudo-holomorphic spheres

abstract:
  This is the first part of a trilogy where we apply the theory of virtual
manifold/orbifolds developed by the first named author and Tian to study the
Gromov-Witten moduli spaces. In this paper, we resolve the main analytic issue
arising from the lack of differentiability of $PSL(2, \C)$-action on spaces of
$W^{1, p}$-maps from the Riemann sphere to a symplectic manifold $(X, \omega,
J)$ with a non-zero homology class $A$. In particular, we establish the slice
and tubular neighbourhood theorems for $PSL(2, \C)$-action along smooth maps,
and construct a $PSL(2, \C)$-obstruction bundle along $PSL(2, \C)$-orbit of a
pseudo-holomorphic map representing a point in the moduli space $\cM_{0, 0}(X,
A)$. In Sections 2 and 3 of this paper, we explain an integration theory on
virtual orbifolds using proper \'etale groupoids and establish the virtual
neighborhood technique for a general orbifold Fredholm system. When the moduli
space $\cM_{0, 0}(X, A)$ of pseudo-holomorphic spheres in $(X, \omega, J)$ is
compact, applying the virtual neighborhood technique developed in Section 3, we
obtain a virtual system for the moduli space $\cM_{0, 0}(X, A)$ of
pseudo-holomorphic spheres in $(X, \omega, J)$ and show that the genus zero
Gromov-Witten invariant is well-defined.


title: Bayesian State-Space Modelling on High-Performance Hardware Using LibBi

abstract:
  LibBi is a software package for state-space modelling and Bayesian inference
on modern computer hardware, including multi-core central processing units
(CPUs), many-core graphics processing units (GPUs) and distributed-memory
clusters of such devices. The software parses a domain-specific language for
model specification, then optimises, generates, compiles and runs code for the
given model, inference method and hardware platform. In presenting the
software, this work serves as an introduction to state-space models and the
specialised methods developed for Bayesian inference with them. The focus is on
sequential Monte Carlo (SMC) methods such as the particle filter for state
estimation, and the particle Markov chain Monte Carlo (PMCMC) and SMC^2 methods
for parameter estimation. All are well-suited to current computer hardware. Two
examples are given and developed throughout, one a linear three-element
windkessel model of the human arterial system, the other a nonlinear Lorenz '96
model. These are specified in the prescribed modelling language, and LibBi
demonstrated by performing inference with them. Empirical results are
presented, including a performance comparison of the software with different
hardware configurations.


title: A decomposition theorem for immersions of product manifolds

abstract:
  We introduce polar metrics on a product manifold, which have product and
warped product metrics as special cases. We prove a de Rham-type theorem
characterizing Riemannian manifolds that can be locally decomposed as a product
manifold endowed with a polar metric. For a product manifold endowed with a
polar metric, our main result gives a complete description of all its isometric
immersions into a space form whose second fundamental forms are adapetd to its
product structure, in the sense that the tangent spaces to each factor are
preserved by all shape operators. This is a far-reaching generalization of a
basic decomposition theorem for isometric immersions of Riemannian products due
to Moore as well as its extension by N\"olker to isometric immersions of warped
products.


title:
An analysis of B meson decays to two light pseudoscalar nonets with
  deltaS=1 in QCD factorization approach

abstract:
  We have performed a numerical analysis of branching ratios and direct
CP-asymmetries of B meson decays to two light pseudoscalar nonets with deltaS=1
using QCD improved factorization. The parameters related to B meson including
its semileptonic form factors, strange quark mass and the CKM phase angle have
been varied over a limited range and phenomenological parameters used to
parameterize divergences in hard spectator scattering and weak annihilation
have been varied over a wide range simultaneously with an aim to achieve a fit
of branching ratios and some direct CP-asymmetries. A good fit for the majority
of the parameters has been achieved indicating that the standard model is quite
satisfactory in accounting for these processes.


abstract:
  We define Eisenstein series on rank 2 hyperbolic Kac--Moody groups over R,
induced from quasi--characters. We prove convergence of the constant term and
hence the almost everywhere convergence of the Eisenstein series. We define and
calculate the degenerate Fourier coefficients. We also consider Eisenstein
series induced from cusp forms and show that these are entire functions.


title:
The orbital periods of subdwarf B binaries produced by the first stable
  Roche overflow channel

abstract:
  Long-orbital-period subdwarf B (sdB) stars with main-sequence companions are
believed to be the product of stable Roche Lobe overflow (RLOF), a scenario
challenged by recent observations. Here we represent the results of a
systematic study of the orbital-period distribution of sdB binaries in this
channel using detailed binary evolution calculations. We show that the observed
orbital-period distribution of long-period sdB binaries can be well explained
by this scenario. Furthermore, we find that, if the progenitors of the sdB
stars have initial masses below the helium flash mass, the sdB binaries
produced from stable RLOF follow a unique mass -- orbital period relation for a
given metallicity $Z$; increasing the orbital period from $\sim 400$ to $\sim
1100$\,d corresponds to increasing the mass of the sdB star from $\sim 0.40$ to
$\sim 0.49\,M_\odot$ for $Z=0.02$. We suggest that the longest sdB binaries
(with orbital period $> 1100$\,d) could be the result of atmospheric RLOF. The
mass -- orbital period relation can be tested observationally if the mass of
the sdB star can be determined precisely, e.g.\ from asteroseismology. Using
this relation, we revise the orbital period distribution of sdB binaries
produced by the first stable RLOF channel for the best fitting model of Han et
al (2003), and show that the orbital period has a peak around 830\,d.


title:
A Pseudo su(1,1)-Algebraic Deformation of the Cooper-Pair in the
  su(2)-Algebraic Many-Fermion Model

abstract:
  A pseudo su(1,1)-algebra is formulated as a possible deformation of the
Cooper-pair in the su(2)-algebraic many-fermion system. With the aid of this
algebra, it is possible to describe behavior of individual fermions which are
generated as the result of interaction with the external environment. The form
presented in this paper is a generalization of a certain simple case developed
recently by the present authors. Basic idea follows the su(1,1)-algebra in the
Schwinger boson representation for treating energy transfer between the
harmonic oscillator and the external environment. Hamiltonian is given under
the idea of the phase space doubling in the thermo-field dynamics formalism and
the time-dependent variational method is applied to this Hamiltonian. Its trial
state is constructed in the frame deformed from the BCS-Bogoliubov approach to
the superconductivity. Several numerical results are shown.


title: Quark Propagation in the Instantons of Lattice QCD

abstract:
  We quantitatively examine the extent to which instanton degress of freedom,
contained within standard Monte-carlo generated gauge-field configurations, can
maintain the characteristic features of the mass and renormalisation functions
of the non-perturbative quark propagator. We use over-improved stout-link
smearing to isolate instanton effects on the lattice. Using a variety of
measures, we illustrate how gauge fields consisting almost solely of
instanton-like objects are produced after only 50 sweeps of smearing. We find a
full vacuum, with a packing fraction more than three times larger than
phenomenological models predict. We calculate the overlap quark propagator on
these smeared configurations, and find that even at high levels of smearing the
majority of the characteristic features of the propagator are reproduced. We
thus conclude that instantons contained within standard Monte-carlo generated
gauge-field configurations are the degrees of freedom responsible for the
dynamical generation of mass observed in lattice QCD.


title:
All-Distances Sketches, Revisited: HIP Estimators for Massive Graphs
  Analysis

abstract:
  Graph datasets with billions of edges, such as social and Web graphs, are
prevalent, and scalable computation is critical. All-distances sketches (ADS)
[Cohen 1997], are a powerful tool for scalable approximation of statistics.
  The sketch is a small size sample of the distance relation of a node which
emphasizes closer nodes. Sketches for all nodes are computed using a nearly
linear computation and estimators are applied to sketches of nodes to estimate
their properties.
  We provide, for the first time, a unified exposition of ADS algorithms and
applications. We present the Historic Inverse Probability (HIP) estimators
which are applied to the ADS of a node to estimate a large natural class of
statistics. For the important special cases of neighborhood cardinalities (the
number of nodes within some query distance) and closeness centralities, HIP
estimators have at most half the variance of previous estimators and we show
that this is essentially optimal. Moreover, HIP obtains a polynomial
improvement for more general statistics and the estimators are simple,
flexible, unbiased, and elegant.
  For approximate distinct counting on data streams, HIP outperforms the
original estimators for the HyperLogLog MinHash sketches (Flajolet et al.
2007), obtaining significantly improved estimation quality for this
state-of-the-art practical algorithm.


title:
Third-Order Edge Statistics: Contour Continuation, Curvature, and
  Cortical Connections

abstract:
  Association field models have attempted to explain human contour grouping
performance, and to explain the mean frequency of long-range horizontal
connections across cortical columns in V1. However, association fields only
depend on the pairwise statistics of edges in natural scenes. We develop a
spectral test of the sufficiency of pairwise statistics and show there is
significant higher order structure. An analysis using a probabilistic spectral
embedding reveals curvature-dependent components.


title:
A symmetry-respecting topologically-ordered surface phase of 3d electron
  topological insulators

abstract:
  A 3d electron topological insulator (ETI) is a phase of matter protected by
particle-number conservation and time-reversal symmetry. It was previously
believed that the surface of an ETI must be gapless unless one of these
symmetries is broken. A well-known symmetry-preserving, gapless surface
termination of an ETI supports an odd number of Dirac cones. In this paper we
deduce a symmetry-respecting, gapped surface termination of an ETI, which
carries an intrinsic 2d topological order, Moore-Read x anti-semion. The
Moore-Read sector supports non-Abelian charge 1/4 anyons, while the Abelian,
anti-semion sector is electrically neutral. Time-reversal symmetry is
implemented in this surface phase in a highly non-trivial way. Moreover, it is
impossible to realize this phase strictly in 2d, simultaneously preserving its
implementation of both the particle number and time-reversal symmetries. A 1d
edge on the ETI surface between the topologically-ordered phase and the
topologically trivial time-reversal-broken phase with a Hall conductivity
sigma_H = 1/2, carries a right-moving neutral Majorana mode, a right-moving
bosonic charge mode and a left-moving bosonic neutral mode. The
topologically-ordered phase is separated from the surface superconductor by a
direct second order phase transition in the XY* universality class, which is
driven by the condensation of a charge 1/2 boson, when approached from the
topologically-ordered side, and proliferation of a flux 4\pi-vortex, when
approached from the superconducting side. In addition, we prove that
time-reversal invariant (interacting) electron insulators with no intrinsic
topological order and electromagnetic response characterized by a \theta-angle,
\theta = \pi, do not exist if the electrons transform as Kramers singlets under
time-reversal.


title:
Terrestrial Planet Formation During the Migration and Resonance
  Crossings of the Giant Planets

abstract:
  The newly formed giant planets may have migrated and crossed a number of
mutual mean motion resonances (MMRs) when smaller objects (embryos) were
accreting to form the terrestrial planets. We investigated the effects of the
planetesimal-driven migration of Jupiter and Saturn, and the influence of their
mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by
performing N-body simulations. These simulations considered distinct timescales
of MMR crossing and planet migration. In total, 68 high-resolution simulation
runs using 2000 disk planetesimals were performed, which was a significant
improvement on previously published results. Even when the effects of the 1:2
MMR crossing and planet migration were included in the system, Venus and Earth
analogs (considering both orbits and masses) successfully formed in several
runs. In addition, we found that the orbits of planetesimals beyond a ~1.5-2 AU
were dynamically depleted by the strengthened sweeping secular resonances
associated with Jupiter's and Saturn's more eccentric orbits (relative to
present-day) during planet migration. However, this depletion did not prevent
the formation of massive Mars analogs (planets with more than 1.5 times Mars'
mass). Although late MMR crossings (at t > 30 Myr) could remove such planets,
Mars-like small mass planets survived on overly excited orbits (high e and/or
i), or were completely lost in these systems. We conclude that the orbital
migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely
to provide suitable orbital conditions for the formation of solar system
terrestrial planets. This suggests that to explain Mars' small mass and the
absence of other planets between Mars and Jupiter, the outer asteroid belt must
have suffered a severe depletion due to interactions with Jupiter/Saturn, or by
an alternative mechanism (e.g., rogue super-Earths).


title:
Fundamental parameters of 16 late-type stars derived from their angular
  diameter measured with VLTI/AMBER

abstract:
  Thanks to their large angular dimension and brightness, red giants and
supergiants are privileged targets for optical long-baseline interferometers.
Sixteen red giants and supergiants have been observed with the VLTI/AMBER
facility over a two-years period, at medium spectral resolution (R=1500) in the
K band. The limb-darkened angular diameters are derived from fits of stellar
atmospheric models on the visibility and the triple product data. The angular
diameters do not show any significant temporal variation, except for one
target: TX Psc, which shows a variation of 4% using visibility data. For the
eight targets previously measured by Long-Baseline Interferometry (LBI) in the
same spectral range, the difference between our diameters and the literature
values is less than 5%, except for TX Psc, which shows a difference of 11%. For
the 8 other targets, the present angular diameters are the first measured from
LBI. Angular diameters are then used to determine several fundamental stellar
parameters, and to locate these targets in the Hertzsprung-Russell Diagram
(HRD). Except for the enigmatic Tc-poor low-mass carbon star W Ori, the
location of Tc-rich stars in the HRD matches remarkably well the
thermally-pulsating AGB, as it is predicted by the stellar-evolution models.
For pulsating stars with periods available, we compute the pulsation constant
and locate the stars along the various sequences in the Period -- Luminosity
diagram. We confirm the increase in mass along the pulsation sequences, as
predicted by the theory, except for W Ori which, despite being less massive,
appears to have a longer period than T Cet along the first-overtone sequence.


title:
Ultra-broadband strong light absorption based on thin multilayered
  metamaterials

abstract:
  Light absorption plays an important role in many research areas. Here, we
propose and demonstrate a thin ultra-broadband strong light absorber consisting
of periodic taper arrays on a gold substrate.


title:
A Molecular Line Survey of the Carbon-Rich Proto-Planetary Nebula AFGL
  2688 in the 3mm and 1.3mm Windows

abstract:
  We present a spectral line survey of the proto-planetary nebula AFGL 2688 in
the frequency ranges of 71-111 GHz, 157-160 GHz, and 218-267 GHz using the
Arizona Radio Observatory 12m telescope and the Heinrich Hertz Submillimeter
Telescope. A total of 143 individual spectral features associated with 32
different molecular species and isotopologues were identified. The molecules
C3H, CH3CN, H2CO, H2CS, and HCO+ were detected for the first time in this
object. By comparing the integrated line strengths of different transitions, we
are able to determine the rotation temperatures, column densities, and
fractional abundances of the detected molecules. The C, O, and N isotopic
ratios in AFGL 2688 are compared with those in IRC+10216 and the Sun, and were
found to be consistent with stellar nucleosynthesis theory. Through comparisons
of molecular line strengths in asymptotic giant branch stars, proto-planetary
nebulae, and planetary nebulae, we discuss the evolution in circumstellar
chemistry in the late stages of evolution.


title:
Particle production in Ultra-relativistic Heavy-Ion Collisions : A
  Statistical-Thermal Model Review

abstract:
  The current status of various thermal and statistical descriptions of
particle production in the ultra-relativistic heavy-ion collisions experiments
is presented in detail. We discuss the formulation of various types of thermal
models of a hot and dense hadron gas (HG) and the methods incorporated in
implementing the interactions between hadrons. We first obtain the
parameterization of center-of-mass energy ($\sqrt{s_{NN}}$) in terms of
temperature ($T$) and baryon chemical potential ($\mu_B$) obtained by analyzing
the particle ratios at the freeze-out over a broad energy range from the lowest
Alternating Gradient Synchrotron (AGS) energy to the highest Relativistic
Heavy-Ion Collider (RHIC) energies. The results of various thermal models
together with the experimental results for the various ratios of yields of
produced hadrons are then compared. We have derived some new universal
conditions emerging at the chemical freeze-out of HG fireball which demonstrate
the independence with respect to the energy as well as the structure of the
nuclei used in the collision. Further, we perform the calculation of various
transport properties of HG such as shear viscosity-to-entropy density ratio
($\eta/s$) etc. using thermal model and compare with the results of other
models. We also present the calculation of the rapidity as well as transverse
mass spectra of various hadrons in the thermal HG model. The purpose of this
review article is to organize and summarize the experimental data obtained in
various experiments with heavy-ion collisions and then to examine and analyze
them using thermal models so that a firm conclusion regarding the formation of
quark-gluon plasma (QGP) can be obtained.


title:
Enhancement of non-resonant dielectric cloaks using anisotropic
  composites

abstract:
  Cloaking techniques conceal objects by controlling the flow of
electromagnetic waves to minimize scattering. Herein, the effectiveness of
homogenized anisotropic materials in non-resonant dielectric multilayer
cloaking is studied. Because existing multilayer cloaking by isotropic
materials can be regarded as homogenous anisotropic cloaking from a macroscopic
view, anisotropic materials can be efficiently designed through optimization of
their physical properties. Anisotropic properties can be realized in two-phase
composites if the physical properties of the material are within appropriate
bounds. The optimized anisotropic physical properties are identified by a
numerical optimization technique based on a full-wave simulation using the
finite element method. The cloaking performance measured by the total
scattering width is improved by about 2.8% and 25% in eight- and three-layer
cylindrical cloaking materials, respectively, compared with multilayer cloaking
by isotropic materials. In all cloaking examples, the optimized microstructures
of the two-phase composites are identified as the simple lamination of two
materials, which maximizes the anisotropy. The same performance as published
for eight-layer cloaking by isotropic materials is achieved by three-layer
cloaking using the anisotropic material. Cloaking with an approximately 50%
reduction of total scattering width is achieved even in an octagonal object.
Since the cloaking effect can be realized using just a few layers of the
laminated anisotropic dielectric composite, this may have an advantage in the
mass production of cloaking devices.


title: Quantifying Long-Term Scientific Impact

abstract:
  The lack of predictability of citation-based measures frequently used to
gauge impact, from impact factors to short-term citations, raises a fundamental
question: Is there long-term predictability in citation patterns? Here, we
derive a mechanistic model for the citation dynamics of individual papers,
allowing us to collapse the citation histories of papers from different
journals and disciplines into a single curve, indicating that all papers tend
to follow the same universal temporal pattern. The observed patterns not only
help us uncover basic mechanisms that govern scientific impact but also offer
reliable measures of influence that may have potential policy implications.


title:
Feature Learning by Multidimensional Scaling and its Applications in
  Object Recognition

abstract:
  We present the MDS feature learning framework, in which multidimensional
scaling (MDS) is applied on high-level pairwise image distances to learn
fixed-length vector representations of images. The aspects of the images that
are captured by the learned features, which we call MDS features, completely
depend on what kind of image distance measurement is employed. With properly
selected semantics-sensitive image distances, the MDS features provide rich
semantic information about the images that is not captured by other feature
extraction techniques. In our work, we introduce the iterated
Levenberg-Marquardt algorithm for solving MDS, and study the MDS feature
learning with IMage Euclidean Distance (IMED) and Spatial Pyramid Matching
(SPM) distance. We present experiments on both synthetic data and real images
--- the publicly accessible UIUC car image dataset. The MDS features based on
SPM distance achieve exceptional performance for the car recognition task.


title: Rethinking Abstractions for Big Data: Why, Where, How, and What

abstract:
  Big data refers to large and complex data sets that, under existing
approaches, exceed the capacity and capability of current compute platforms,
systems software, analytical tools and human understanding. Numerous lessons on
the scalability of big data can already be found in asymptotic analysis of
algorithms and from the high-performance computing (HPC) and applications
communities. However, scale is only one aspect of current big data trends;
fundamentally, current and emerging problems in big data are a result of
unprecedented complexity--in the structure of the data and how to analyze it,
in dealing with unreliability and redundancy, in addressing the human factors
of comprehending complex data sets, in formulating meaningful analyses, and in
managing the dense, power-hungry data centers that house big data.
  The computer science solution to complexity is finding the right
abstractions, those that hide as much triviality as possible while revealing
the essence of the problem that is being addressed. The "big data challenge"
has disrupted computer science by stressing to the very limits the familiar
abstractions which define the relevant subfields in data analysis, data
management and the underlying parallel systems. As a result, not enough of
these challenges are revealed by isolating abstractions in a traditional
software stack or standard algorithmic and analytical techniques, and attempts
to address complexity either oversimplify or require low-level management of
details. The authors believe that the abstractions for big data need to be
rethought, and this reorganization needs to evolve and be sustained through
continued cross-disciplinary collaboration.


title: Energy of a rotating Bose-Einstein condensate in a harmonic trap

abstract:
  The state of a rotating Bose-Einstein condensate in a harmonic trap is
modeled by a wave function that minimizes the Gross-Pitaevskii functional. The
resulting minimization problem has two new features compared to other similar
functionals arising in condensed matter physics, such as the Ginzburg-Landau
functional. Namely, the wave function is defined in all the plane and is
normalized relative to the $L^2$-norm. This paper deals with the situation when
the coupling constant tends to $0$ (Thomas-Fermi regime) and the rotation speed
is large compared with the first critical speed.
  It is given the leading order estimate of the ground state energy together
with the location of the vortices of the minimizing wave function in the bulk
of the condensate. When the rotation speed is inversely proportional to the
coupling constant, the condensate is confined in an elliptical region whose
conjugate diameter shrinks and whose transverse diameter expands as the
rotation speed increases.


title: Matching objects across the textured-smooth continuum

abstract:
  The problem of 3D object recognition is of immense practical importance, with
the last decade witnessing a number of breakthroughs in the state of the art.
Most of the previous work has focused on the matching of textured objects using
local appearance descriptors extracted around salient image points. The
recently proposed bag of boundaries method was the first to address directly
the problem of matching smooth objects using boundary features. However, no
previous work has attempted to achieve a holistic treatment of the problem by
jointly using textural and shape features which is what we describe herein. Due
to the complementarity of the two modalities, we fuse the corresponding
matching scores and learn their relative weighting in a data specific manner by
optimizing discriminative performance on synthetically distorted data. For the
textural description of an object we adopt a representation in the form of a
histogram of SIFT based visual words. Similarly the apparent shape of an object
is represented by a histogram of discretized features capturing local shape. On
a large public database of a diverse set of objects, the proposed method is
shown to outperform significantly both purely textural and purely shape based
approaches for matching across viewpoint variation.


title:
Accumulation of periodic points for local uniformly quasiregular
  mappings

abstract:
  We consider accumulation of periodic points in local uniformly quasiregular
dynamics. Given a local uniformly quasiregular mapping $f$ with a countable and
closed set of isolated essential singularities and their accumulation points on
a closed Riemannian manifold, we show that points in the Julia set are
accumulated by periodic points. If, in addition, the Fatou set is non-empty and
connected, the accumulation is by periodic points in the Julia set itself. We
also give sufficient conditions for the density of repelling periodic points.


title: Quantum Dynamics in Classical Spin Baths

abstract:
  A formalism for studying the dynamics of quantum systems embedded in
classical spin baths is introduced. The theory is based on generalized
antisymmetric brackets and predicts the presence of open-path off-diagonal
geometric phases in the evolution of the density matrix. The weak coupling
limit of the equation can be integrated by standard algorithms and provides a
non-Markovian approach to the computer simulation of quantum systems in
classical spin environments. It is expected that the theory and numerical
schemes presented here have a wide applicability.


title: Strange quark matter in strong magnetic fields within a confining model

abstract:
  We construct an equation of state of strange quark matter in strong magnetic
field within a confining model. The confinement is modeled by means of the
Richardson potential for quark-quark interaction modified suitably to account
for strong magnetic field. We compare our results for the equation of state and
magnetization of matter to those derived within the MIT bag model. The
differences between these models arise mainly due to the momentum dependence of
the strong interaction between quarks in the Richardson model. Specifically, we
find that the magnetization of strange quark matter in this model has much more
pronounced de Haas-van Alf\'{v}en oscillations than in the MIT bag model, which
is the consequence of the (static) gluon-exchange structure of the confining
potential.


title: Aggregation and long memory: recent developments

abstract:
  It is well-known that the aggregated time series might have very different
properties from those of the individual series, in particular, long memory. At
the present time, aggregation has become one of the main tools for modelling of
long memory processes. We review recent work on contemporaneous aggregation of
random-coefficient AR(1) and related models, with particular focus on various
long memory properties of the aggregated process.


title:
The Effect of Communication and Synchronization on Amdahl Law in
  Multicore Systems

abstract:
  This work analyses the effects of sequential-to-parallel synchronization and
inter-core communication on multicore performance, speedup and scaling. A
modification of Amdahl law is formulated, to reflect the finding that parallel
speedup is lower than originally predicted, due to these effects. In
applications with high inter-core communication requirements, the workload
should be executed on a small number of cores, and applications of high
sequential-to-parallel synchronization requirements may better be executed by
the sequential core, even when f, the Amdahl fraction of parallelization, is
very close to 1. To improve the scalability and performance speedup of a
multicore, it is as important to address the synchronization and connectivity
intensities of parallel algorithms as their parallelization factor.


title: Stably-interior points and the Semicontinuity of the Automorphism group

abstract:
  The first result is the semicontinuity of automorphism groups for the
collection of complex two-dimensional bounded pseudoconvex domains with smooth
boundary of finite D'Angelo type. The method of proof is new so that it
simplifies the previous proof of earlier semicontinuity theorems on bounded
strongly pseudoconvex daomains by Greene and Krantz in the early 1980s.


title: Fission of pre-actinide nuclei

abstract:
  A study of photofission on 181Ta nucleus induced by bremsstrahlung photons
with endpoint energies of 50 and 3500 MeV has been performed. The fission
yields have been measured by using the induced-activity method in an off-line
analysis. The absolute photofission cross sections for the tantalum target at
50 and 3500 MeV are found to be 5.4 \pm 1.1 microb and 0.77\pm0.11 mb,
respectively, and the corresponding deduced fissilities are (0.23\pm0.05) x
10^{-3} and (2.9 \pm 0.9) x 10^{-3}. Mass- and charge-yield distributions were
derived from the data. The results were compared with the simulated results
from CRISP code for multi-modal fission by assuming symmetrical fission mode.


title: Graver degrees are not polynomially bounded by true circuit degrees

abstract:
  Let $I_A$ be a toric ideal. We prove that the degrees of the elements of the
Graver basis of $I_A$ are not polynomially bounded by the true degrees of the
circuits of $I_A$.


title: Sounding stellar cycles with Kepler - II. Ground-based observations

abstract:
  We have monitored 20 Sun-like stars in the Kepler field-of-view for excess
flux with the FIES spectrograph on the Nordic Optical Telescope since the
launch of Kepler spacecraft in 2009. These 20 stars were selected based on
their asteroseismic properties to sample the parameter space (effective
temperature, surface gravity, activity level etc.) around the Sun. Though the
ultimate goal is to improve stellar dynamo models, we focus the present paper
on the combination of space-based and ground-based observations can be used to
test the age-rotation-activity relations.
  In this paper we describe the considerations behind the selection of these 20
Sun-like stars and present an initial asteroseismic analysis, which includes
stellar age estimates. We also describe the observations from the Nordic
Optical Telescope and present mean values of measured excess fluxes. These
measurements are combined with estimates of the rotation periods obtained from
a simple analysis of the modulation in photometric observations from Kepler
caused by starspots, and asteroseismic determinations of stellar ages, to test
relations between between age, rotation and activity.


title: Curved traversable wormholes in (3+1)-dimensional spacetime

abstract:
  We present the general method of constructing curved traversable wormholes in
(3+1)-d spacetime and proceed to thoroughly discuss the physics of a zero tidal
force metric without cross-terms. The (3+1)-d solution is compared with the
recently studied lower-dimensional counterpart, where we identify that the much
richer physics - involving pressures and shear forces of the mass-energy fluid
supporting the former - is attributed to the mixing of all three spatial
coordinates. Our (3+1)-d universe is the lowest dimension where such nontrivial
terms appear. An explicit example, the static zero tidal force (3+1)-d catenary
wormhole is analysed and we show the existence of a geodesic through it
supported locally by non-exotic matter, similar to the (2+1)-d version. A key
difference is that positive mass-energy is used to support the entire (3+1)-d
catenary wormhole, though violation of the null energy condition in certain
regions is inevitable. This general approach of first constructing the geometry
of the spacetime and then using the field equations to determine the physics to
support it has the potential to discover new solutions in general relativity or
to generalise existing ones. For instance, the metric of a time-evolving
inflationary wormhole with a conformal factor can actually be geometrically
constructed using our method.


title: Motional Coherence of Fermions Immersed in a Bose Gas

abstract:
  We prepare a superposition of two motional states by addressing lithium atoms
immersed in a Bose-Einstein condensate of sodium with a species-selective
potential. The evolution of the superposition state is characterized by the
populations of the constituent states as well as their coherence. The latter we
extract employing a novel scheme analogous to the spin-echo technique.
Comparing the results directly to measurements on freely-evolving fermions
allows us to isolate the decoherence effects induced by the bath. In our
system, the decoherence time is close to the maximal possible value since the
decoherence is dominated by population relaxation processes. The measured data
are in good agreement with a theoretical model based on Fermi's golden rule.


title: Symmetries in LDDMM with higher order momentum distributions

abstract:
  In some implementations of the Large Deformation Diffeomorphic Metric Mapping
formulation for image registration we consider the motion of particles which
locally translate image data. We then lift the motion of the particles to
obtain a motion on the entire image. However, it is certainly possible to
consider particles which do more than translate, and this is what will be
described in this paper. As the unreduced Lagrangian associated to EPDiff
possesses $\Diff(M)$ symmetry, it must also exhibit $G \subset \Diff(M)$
symmetry, for any Lie subgroup. In this paper we will describe a tower of Lie
groups $G^{(0)} \subseteq G^{(1)} \subseteq G^{(2)} \subseteq...$ which
correspond to preserving $k$-th order jet-data. The reduced configuration
spaces $Q^{(k)} := \Diff(M) / G^{(k)}$ will be finite-dimensional (in
particular, $Q^{(0)}$ is the configuration manifold for $N$ particles in $M$).
We will observe that $G^{(k)}$ is a normal subgroup of $G^{(0)}$ and so the
quotient $G^{(0)} / G^{(k)}$ is itself a (finite dimensional) Lie group which
acts on $Q^{(k)}$. This makes $Q^{(k)}$ a principle bundle over $Q^{(0)}$ and
the reduced geodesic equations on $Q^{(k)}$ will possess $G^{(0)} /
G^{(k)}$-symmetry. Noether's theorem implies the existence of conserved momenta
for the reduced system on $T^{\ast}Q^{(k)}$.


title:
Surface structure of Bi2Se3(111) determined by low-energy electron
  diffraction and surface X-ray diffraction

abstract:
  The surface structure of the prototypical topological insulator Bi2Se3 is
determined by low-energy electron diffraction and surface X-ray diffraction at
room temperature. Both approaches show that the crystal is terminated by an
intact quintuple layer. Specifically, an alternative termination by a bismuth
bilayer is ruled out. Surface relaxations obtained by both techniques are in
good agreement with each other and found to be small. This includes the
relaxation of the van der Waals gap between the first two quintuple layers.


title: A note on the Matlis dual of a certain injective hull

abstract:
  Let $(R,\mathfrak{m})$ denote a local ring with $E = E_R(R/\mathfrak{m})$ the
injective hull of the residue field. Let $\mathfrak{p} \in \Spec R$ denote a
prime ideal with $\dim R/\mathfrak{p} = 1$, and let $E_R(R/\mathfrak{p})$ be
the injective hull of $R/\mathfrak{p}$. As the main result we prove that the
Matlis dual $\Hom_R(E_R(R/\mathfrak{p}), E)$ is isomorphic to
$\hat{R_{\mathfrak{p}}}$, the completion of $R_{\mathfrak{p}}$, if and only if
$R/\mathfrak{p}$ is complete. In the case of $R$ a one dimensional domain there
is a complete description of $Q \otimes_R \hat{R}$ in terms of the completion
$\hat{R}$.


title:
Dynamic Transcript Profiling of Candida Albicans Infection in Zebrafish:
  a Pathogen-Host Interaction Study

abstract:
  Candida albicans is responsible for a number of life-threatening infections
and causes considerable morbidity and mortality in immunocompromised patients.
Previous studies of C. albicans pathogenesis have suggested several steps must
occur before virulent infection, including early adhesion, invasion, and late
tissue damage. However, the mechanism that triggers C. albicans transformation
from yeast to hyphae form during infection has yet to be fully elucidated. This
study used a systems biology approach to investigate C. albicans infection in
zebrafish. The surviving fish were sampled at different post-infection time
points to obtain time-lapsed, genome-wide transcriptomic data from both
organisms, which were accompanied with in sync histological analyses. Principal
component analysis (PCA) was used to analyze the dynamic gene expression
profiles of significant variations in both C. albicans and zebrafish. The
results categorized C. albicans infection into three progressing phases:
adhesion, invasion, and damage. Such findings were highly supported by the
corresponding histological analysis. Furthermore, the dynamic interspecies
transcript profiling revealed that C. albicans activated its filamentous
formation during invasion and the iron scavenging functions during the damage
phases, whereas zebrafish ceased its iron homeostasis function following
massive hemorrhage during the later stages of infection. This was followed by
massive hemorrhaging toward the end stage of infection. Most of the immune
related genes were expressed as the infection progressed from invasion to the
damage phase. Such global, inter-species evidence of virulence-immune and iron
competition dynamics during C. albicans infection could be crucial in
understanding control fungal pathogenesis.


title:
Effective preparation and collisional decay of atomic condensate in
  excited bands of an optical lattice

abstract:
  We present a method for the effective preparation of a Bose-Einstein
condensate (BEC) into the excited bands of an optical lattice via a
standing-wave pulse sequence. With our method, the BEC can be prepared in
either a single Bloch state in a excited-band, or a coherent superposition of
states in different bands. Our scheme is experimentally demonstrated by
preparing a $^{87}$Rb BEC into the $d$-band and the superposition of $s$- and
$d$-band states of a one-dimensional optical lattice, within a few tens of
microseconds. We further measure the decay of the BEC in the $d$-band state,
and carry an analytical calculation for the collisional decay of atoms in the
excited-band states. Our theoretical and experimental results consist well.


title: Jacobian Conjecture in two dimension

abstract:
  Let $(P, Q)$ be a pair of Jacobian polynomials. We can show that $ <P,
Q>+l+2g(P)-2= 0= <P, [P,Q]>$, where $<f, g>$ is the intersection number of $f,
g\in \CC[x, y]$ in the affine plane, $l$ is the number of branch at point at
infinity and $g(P)$ is the geometric genus of affine curve defined by $P$.
Hence we can show that every Jacobian polynomial defines a smooth rational
curve with one point at infinity. It is sufficient to fix the Jacobian
conjecture in two dimension by the Abhyankar theorem or the
Abhyankar-Moh-Suzuki theorem.


title: Metric number theory, lacunary series and systems of dilated functions

abstract:
  By a classical result of Weyl, for any increasing sequence $(n_k)_{k \geq 1}$
of integers the sequence of fractional parts $(\{n_k x\})_{k \geq 1}$ is
uniformly distributed modulo 1 for almost all $x \in [0,1]$. Except for a few
special cases, e.g. when $n_k=k, k \geq 1$, the exceptional set cannot be
described explicitly. The exact asymptotic order of the discrepancy of $(\{n_k
x\})_{k \geq 1}$ is only known in a few special cases, for example when
$(n_k)_{k \geq 1}$ is a (Hadamard) lacunary sequence, that is when $n_{k+1}/n_k
\geq q > 1, k \geq 1$. In this case of quickly increasing $(n_k)_{k \geq 1}$
the system $(\{n_k x\})_{k \geq 1}$ (or, more general, $(f(n_k x))_{k \geq 1}$
for a 1-periodic function $f$) shows many asymptotic properties which are
typical for the behavior of systems of \emph{independent} random variables.
Precise results depend on a fascinating interplay between analytic,
probabilistic and number-theoretic phenomena.
  Without any growth conditions on $(n_k)_{k \geq 1}$ the situation becomes
much more complicated, and the system $(f(n_k x))_{k \geq 1}$ will typically
fail to satisfy probabilistic limit theorems. An important problem which
remains is to study the almost everywhere convergence of series
$\sum_{k=1}^\infty c_k f(k x)$, which is closely related to finding upper
bounds for maximal $L^2$-norms of the form $$ \int_0^1 (\max_{1 \leq M \leq N}|
\sum_{k=1}^M c_k f(kx)|^2 dx. $$ The most striking example of this connection
is the equivalence of the Carleson convergence theorem and the Carleson--Hunt
inequality for maximal partial sums of Fourier series. For general functions
$f$ this is a very difficult problem, which is related to finding upper bounds
for certain sums involving greatest common divisors.


title: 12-fold Quasicrystallography from affine F4, B6, and E6

abstract:
  One possible way to obtain the quasicrystallographic structures is the
projections of the higher dimensional lattices into 2D or 3D subspaces. In this
work we introduce a general technique applicable to any higher dimensional
lattice. We point out that the Coxeter number and the Coxeter exponents of a
Coxeter-Weyl group play a crucial role in determining the plane onto which the
lattice to be projected as well as the dihedral symmetry of the quasicrystal
structure. The eigenvectors and eigenvalues of the Cartan matrix are used to
determine the set of orthonormal vectors in nD Euclidean space which lead
suitable choices for the projection subspaces. The maximal dihedral subgroup of
the Coxeter-Weyl group is identified to determine the symmetry of the
quasicrystal structure. We give examples for 12-fold symmetric quasicrystal
structures obtained by projecting the higher dimensional lattices determined by
the affine Coxeter-Weyl groups Wa(F4), Wa(B6) and Wa(E6) . These groups share
the same Coxeter number h=12 with different Coxeter exponents. The dihedral
subgroup D12 of the Coxeter groups can be obtained by defining two generators
R1 and R2 as the products of generators of the Coxeter-Weyl groups. The
reflection generators R1 and R2 operate in the Coxeter planes where the Coxeter
element R1R2 of the Coxeter group represents the rotation of order 12. The
canonical projections (strip projections) of the lattices determine the nature
of the quasicrystallographic structures with 12-fold symmetry as well as the
crystallographic structures with 4-fold and 6-fold symmetry. We note that the
quasicrystal structures obtained from the lattices Wa(F4) and Wa(B6) and are
compatible with the experimental results.


title: Sparse Auto-Regressive: Robust Estimation of AR Parameters

abstract:
  In this paper I present a new approach for regression of time series using
their own samples. This is a celebrated problem known as Auto-Regression.
Dealing with outlier or missed samples in a time series makes the problem of
estimation difficult, so it should be robust against them. Moreover for coding
purposes I will show that it is desired the residual of auto-regression be
sparse. To these aims, I first assume a multivariate Gaussian prior on the
residual and then obtain the estimation. Two simple simulations have been done
on spectrum estimation and speech coding.


title:
Conductance of Ferro- and Antiferro-magnetic single-atom contacts: A
  first-principles study

abstract:
  We present a first-principles study on the spin denpendent conductance of
five single-atom magnetic junctions consisting of a magnetic tip and an adatom
adsorbed on a magnetic surface, i.e., the Co-Co/Co(001) and Ni-X/Ni(001) (X=Fe,
Co, Ni, Cu) junctions. When their spin configuration changes from
ferromagnetism to anti-ferromagnetism, the spin-up conductance increases while
the spin-down one decreases. For the junctions with a magnetic adatom, there is
nearly no spin valve effect as the decreased spin-down conductance counteracts
the increased spin-up one. For the junction with a nonmagnetic adatom
(Ni-Cu/Ni(001)), a spin valve effect is obtained with a variation of 22% in the
total conductance. In addition, the change in spin configuration enhances the
spin filter effect for the Ni-Fe/Ni(001) junction but suppresses it for the
other junctions.


title: On a decoupled linear FEM integrator for Eddy-current-LLG

abstract:
  We propose a numerical integrator for the coupled system of the eddy-current
equation with the nonlinear Landau-Lifshitz-Gilbert equation. The considered
effective field contains a general field contribution, and we particularly
cover exchange, anisotropy, applied field, and magnetic field (stemming from
the eddy-current equation). Even though the considered problem is nonlinear,
our scheme requires only the solution of two linear systems per time-step.
Moreover, our algorithm decouples both equations so that in each time-step, one
linear system is solved for the magnetization, and afterwards one linear system
is solved for the magnetic field. Unconditional convergence -- at least of a
subsequence -- towards a weak solution is proved, and our analysis even
provides existence of such weak solutions. Numerical experiments with a
micromagnetic benchmark problem underline the performance of the proposed
algorithm.


title: Drop impact of shear thickening liquids

abstract:
  The impact of drops of concentrated non-Brownian suspensions (cornstarch and
polystyrene spheres) onto a solid surface is investigated experimentally. The
spreading dynamics and maxi- mal deformation of the droplet of such shear
thickening liquids are found to be markedly different from the impact of
Newtonian drops. A particularly striking observation is that the maximal de-
formation is independent of the drop velocity and that the deformation suddenly
stops during the impact phase. Both observations are due to the
shear-thickening rheology of the suspensions, as is theoretically explained
from a balance between the kinetic energy and the viscously-dissipated en-
ergy, from which we establish a scaling relation between drop maximal
deformation and rheological parameters of concentrated suspensions.


title: On the Galerkin / finite-element method for the Serre equations

abstract:
  A highly accurate numerical scheme is presented for the Serre system of
partial differential equations, which models the propagation of dispersive
shallow water waves in the fully-nonlinear regime. The fully-discrete scheme
utilizes the Galerkin / finite-element method based on smooth periodic splines
in space, and an explicit fourth-order Runge-Kutta method in time. Computations
compared with exact solitary and cnoidal wave solutions show that the scheme
achieves the optimal orders of accuracy in space and time. These computations
also show that the stability of this scheme does not impose restrictive
conditions on the temporal step size. In addition, solitary, cnoidal, and
dispersive shock waves are studied in detail using this numerical scheme for
the Serre system and compared with the 'classical' Boussinesq system for
small-amplitude shallow water waves. The results show that the interaction of
solitary waves in the Serre system is more inelastic. The efficacy of the
numerical scheme for modeling dispersive shocks is shown by comparison with
asymptotic results. These results have application to the modeling of shallow
water waves of intermediate or large amplitude, such as occurs in the nearshore
zone.

categories: physics.class-ph math.AP math.NA physics.flu-dyn


title:
Backward uniqueness for parabolic operators with variable coefficients
  in a half space

abstract:
  It is shown that a function $u$ satisfying
$|\partial_tu+\sum_{i,j}\partial_i(a^{ij}\partial_ju)|\leq N(|u|+|\nabla u|)$,
$|u(x,t)|\leq Ne^{N|x|^2}$ in $\mathbb{R}^n_+\times[0,T]$ and $u(x,0)=0$ in
$\mathbb{R}^n_+$ under certain conditions on $\{a^{ij}\}$ must vanish
identically in $\mathbb{R}^n_+\times[0,T]$. The main point of the result is
that the conditions imposed on $\{a^{ij}\}$ are of the type: $\{a^{ij}\}$ are
Lipschitz and $|\nabla_xa^{ij}(x,t)|\leq \frac{E}{|x|}$, where $E$ is less than
a given number, and the conditions are in some sense optimal.


title:
M2M Communications for E-Health and Smart Grid: An Industry and Standard
  Perspective

abstract:
  An overview of several standardization activities for machine-to-machine
(M2M) communications is presented, analyzing some of the enabling technologies
and applications of M2M in industry sectors such as Smart Grid and e-Health.
This summary and overview of the ongoing work in M2M from the industrial and
standardization perspective complements the prevalent academic perspective of
such publications to date in this field.


title:
Distribution of small dispersive coal dust particles and absorbed
  radioactive chemical elements in conditions of forced acoustic resonance in
  iodine air filter at nuclear power plant

abstract:
  The physical features of distribution of the small dispersive coal dust
particles and the adsorbed radioactive chemical elements and their isotopes in
the absorber with the granular filtering medium with the cylindrical coal
granules were researched in the case of the intensive air dust aerosol stream
flow through the iodine air filter (IAF). It was shown that, at the certain
aerodynamic conditions in the IAF, the generation of the acoustic oscillations
is possible. It was found that the acoustic oscillations generation results in
an appearance of the standing acoustic waves of the air pressure (density) in
the IAF. In the case of the intensive blow of the air dust aerosol, it was
demonstrated that the standing acoustic waves have some strong influences on
both: 1) the dynamics of small dispersive coal dust particles movement and
their accumulation in the IAF; 2) the oversaturation of the cylindrical coal
granules by the adsorbed radioactive chemical elements and their isotopes in
the regions, where the antinodes of the acoustic waves are positioned. Finally,
we completed the comparative analysis of the theoretical calculations with the
experimental results, obtained for the cases of: 1) the experimental
aerodynamic modeling of physical processes of the absorbed radioactive chemical
elements and their isotopes distribution in the IAF; and 2) the
gamma-activation spectroscopy analysis of the absorbed radioactive chemical
elements and their isotopes distribution in the IAF. We made the innovative
propositions on the necessary technical modifications with the purpose to
improve the IAF technical characteristics and increase its operational time at
the nuclear power plant (NPP), going from the completed precise
characterization of the IAF parameters at the long term operation.


title: CSCO Criterion for Entanglement and Heisenberg Uncertainty Principle

abstract:
  We show that quantum entanglement and the Heisenberg uncertainty principle
are inextricably connected. Toward this end, a complete set of commuting
observables (CSCO) criterion for the entanglement is developed. Assuming
(A1,A2,...) and (B1,B2,...) being two CSCO's for a given system, and C being
the matrix, Cij = i [Bi,Aj], for each given row i (i=1,2,...) if at least one
matrix element Cij (j=1,2,...) is nonzero, then for the simultaneous
eigenstates |\psi)=|A1',A2',...) of (A1,A2,...), the simultaneous measurements
of (B1,B2,...) are, in general,entangled. The only exception is when all the
simultaneous eigenstates |\psi)= A1', A2',...), (\psi|C|\psi)=0. This CSCO
criterion may be considered as an extension of the Heisenberg uncertainty
principle to quantum systems with either two (or more) particles or
multi-degrees of freedom (MDF).


title: Strong coupling and quark masses from lattice QCD

abstract: I review lattice QCD calculations of the strong coupling and quark masses.


title:
Relative equilibria and relative periodic solutions in systems with
  time-delay and $S^{1}$ symmetry

abstract:
  We study properties of basic solutions in systems with dime delays and
$S^1$-symmetry. Such basic solutions are relative equilibria (CW solutions) and
relative periodic solutions (MW solutions). It follows from the previous theory
that the number of CW solutions grows generically linearly with time delay
$\tau$. Here we show, in particular, that the number of relative periodic
solutions grows generically as $\tau^2$ when delay increases. Thus, in such
systems, the relative periodic solutions are more abundant than relative
equilibria. The results are directly applicable to, e.g., Lang-Kobayashi model
for the lasers with delayed feedback. We also study stability properties of the
solutions for large delays.


title: Electron dynamics controlled via self-interaction

abstract:
  The dynamics of an electron in a strong laser field can be significantly
altered by radiation reaction. This usually results in a strongly damped
motion, with the electron losing a large fraction of its initial energy. Here
we show that the electron dynamics in a bichromatic laser pulse can be
indirectly controlled by a comparatively small radiation reaction force through
its interplay with the Lorentz force. By changing the relative phase between
the two frequency components of the bichromatic laser field, an
ultrarelativistic electron bunch colliding head-on with the laser pulse can be
deflected in a controlled way, with the deflection angle being independent of
the initial electron energy. The effect is predicted to be observable with
laser powers and intensities close to those of current state-of-the-art
petawatt laser systems.


title: Quantum unique ergodicity for random bases of spectral projections

abstract:
  We consider a random wave model introduced by Zelditch to study the behavior
of typical quasi-modes on a Riemannian manifold. Using the exponential moment
method, we show that random waves satisfy the quantum unique ergodicity
property with probability one under mild growth assumptions.


title:
A chiral quark model for meson electro-production in the region of
  D-wave resonances

abstract:
  The meson scattering and electroproduction amplitudes in the D13, D33 and D15
partial waves are calculated in a coupled-channel formalism incorporating
quasi-bound quark-model states, extending our previous studies of the P11, P33
and S11 partial waves. The vertices of the baryon-meson interaction including
the s- and d-wave pions and $\rho$-mesons, the s-wave $\eta$-meson, and the
$s$- and p-wave $\sigma$-mesons are determined in the Cloudy Bag Model, with
some changes of the parameters to reproduce the widths of the resonances. The
helicity amplitudes and the electroproduction amplitudes exhibit consistent
behavior in all channels but tend to be too weak compared to the experiment. We
discuss possible origins of this discrepancy which arises also in the
constituent quark model calculations.


title: Sparse Recovery of Streaming Signals Using L1-Homotopy

abstract:
  Most of the existing methods for sparse signal recovery assume a static
system: the unknown signal is a finite-length vector for which a fixed set of
linear measurements and a sparse representation basis are available and an
L1-norm minimization program is solved for the reconstruction. However, the
same representation and reconstruction framework is not readily applicable in a
streaming system: the unknown signal changes over time, and it is measured and
reconstructed sequentially over small time intervals.
  In this paper, we discuss two such streaming systems and a homotopy-based
algorithm for quickly solving the associated L1-norm minimization programs: 1)
Recovery of a smooth, time-varying signal for which, instead of using block
transforms, we use lapped orthogonal transforms for sparse representation. 2)
Recovery of a sparse, time-varying signal that follows a linear dynamic model.
For both the systems, we iteratively process measurements over a sliding
interval and estimate sparse coefficients by solving a weighted L1-norm
minimization program. Instead of solving a new L1 program from scratch at every
iteration, we use an available signal estimate as a starting point in a
homotopy formulation. Starting with a warm-start vector, our homotopy algorithm
updates the solution in a small number of computationally inexpensive steps as
the system changes. The homotopy algorithm presented in this paper is highly
versatile as it can update the solution for the L1 problem in a number of
dynamical settings. We demonstrate with numerical experiments that our proposed
streaming recovery framework outperforms the methods that represent and
reconstruct a signal as independent, disjoint blocks, in terms of quality of
reconstruction, and that our proposed homotopy-based updating scheme
outperforms current state-of-the-art solvers in terms of the computation time
and complexity.


title:
Generalised Miller-Morita-Mumford classes for block bundles and
  topological bundles

abstract:
  The most basic characteristic classes of smooth fibre bundles are the
generalised Miller-Morita-Mumford classes, obtained by fibre integrating
characteristic classes of the vertical tangent bundle. In this note we show
that they may be defined for more general families of manifolds than smooth
fibre bundles: smooth block bundles and topological fibre bundles.


title: Magnetic moment suppression in Ba3CoRu2O9: hybridization effect

abstract:
  An unusual orbital state was recently proposed to explain the magnetic and
transport properties of Ba$_3$CoRu$_2$O$_9$ [Phys. Rev. B. {\bf 85}, 041201
(2012)]. We show that this state contradicts to the first Hund's rule and does
not realize in the system under consideration because of a too small
crystal-field splitting in the $t_{2g}$ shell. A strong suppression of the
local magnetic moment in Ba$_3$CoRu$_2$O$_9$ is attributed to a strong
hybridization between the Ru 4$d$ and O 2$p$ states.


title: Gelation for Marcus-Lushnikov process

abstract:
  The Marcus-Lushnikov process is a simple mean field model of coagulating
particles that converges to the homogeneous Smoluchowski equation in the large
mass limit. If the coagulation rates grow sufficiently fast as the size of
particles get large, giant particles emerge in finite time. This is known as
gelation, and such particles are known as gels. Gelation comes in different
flavors: simple, instantaneous and complete. In the case of an instantaneous
gelation, giant particles are formed in a very short time. If all particles
coagulate to form a single particle in a time interval that stays bounded as
total mass gets large, then we have a complete gelation. In this article, we
describe conditions which guarantee any of the three possible gelations with
explicit bounds on the size of gels and the time of their creations.


title: MV-algebras freely generated by finite Kleene algebras

abstract:
  If V and W are varieties of algebras such that any V-algebra A has a reduct
U(A) in W, there is a forgetful functor U: V->W that acts by A |-> U(A) on
objects, and identically on homomorphisms. This functor U always has a left
adjoint F: W->V by general considerations. One calls F(B) the V-algebra freely
generated by the W-algebra B. Two problems arise naturally in this broad
setting. The description problem is to describe the structure of the V-algebra
F(B) as explicitly as possible in terms of the structure of the W-algebra B.
The recognition problem is to find conditions on the structure of a given
V-algebra A that are necessary and sufficient for the existence of a W-algebra
B such that F(B) is isomorphic to A. Building on and extending previous work on
MV-algebras freely generated by finite distributive lattices, in this paper we
provide solutions to the description and recognition problems in case V is the
variety of MV-algebras, W is the variety of Kleene algebras, and B is finitely
generated--equivalently, finite. The proofs rely heavily on the Davey-Werner
natural duality for Kleene algebras, on the representation of finitely
presented MV-algebras by compact rational polyhedra, and on the theory of bases
of MV-algebras.


title:
Anomalous shock fluctuations in TASEP and last passage percolation
  models

abstract:
  We consider the totally asymmetric simple exclusion process with initial
conditions and/or jump rates such that shocks are generated. If the initial
condition is deterministic, then the shock at time t will have a width of order
t^{1/3}. We determine the law of particle positions in the large time limit
around the shock in a few models. In particular, we cover the case where at
both sides of the shock the process of the particle positions is asymptotically
described by the Airy_1 process. The limiting distribution is a product of two
distribution functions, which is a consequence of the fact that at the shock
two characteristics merge and of the slow decorrelation along the
characteristics. We show that the result generalizes to generic last passage
percolation models.


title: Chirality dependence of the absorption cross-section of carbon nanotubes

abstract:
  The variation of the optical absorption of carbon nanotubes with their
geometry has been a long standing question at the heart of both metrological
and applicative issues, in particular because optical spectroscopy is one of
the primary tools for the assessment of the chiral species abundance of
samples. Here, we tackle the chirality dependence of the optical absorption
with an original method involving ultra-efficient energy transfer in
porphyrin/nanotube compounds that allows uniform photo-excitation of all chiral
species. We measure the absolute absorption cross-section of a wide range of
semiconducting nanotubes at their S22 transition and show that it varies by up
to a factor of 2.2 with the chiral angle, with type I nanotubes showing a
larger absorption. In contrast, the luminescence quantum yield remains almost
constant.


title:
Evidence of hot high velocity photoionized plasma falling on actively
  accreting T-Tauri Stars

abstract:
  The HeII (1640 A) line and the resonance doublet of NV (UV1) provide a good
diagnostic tool to constrain the excitation mechanism of hot (Te>40,000K)
atmospheric/magnetospheric plasmas in T Tauri stars (TTSs). Making use of the
data available in the Hubble Space Telescope Archive, this work shows that
there are, at least, two distinct physical components contributing to the
radiation in these tracers: the accretion flow sliding on the magnetosphere and
the atmosphere.
  The NV profiles are symmetric and at rest with respect to the star in most
sources. The velocity dispersion of the profile increases from non-accreting
(40 km/s) to accreting (120 km/s) TTSs suggesting that the macroturbulence in
the line formation region decreases as the stars approach the main sequence.
Evidence of the NV line being formed in a hot solar-like wind has been found in
RW Aur, HN Tau and AA Tau.
  The HeII profile has a strong narrow component that dominates the line flux;
the dispersion of this component ranges from 20 to 60 km/s. The sources of this
radiation is uncertain. Current data suggest that both accretion shocks and
atmospheric emission might contribute to the line flux. In some sources de HeII
line shows a broad and rewards shifted emission component often accompanied by
semiforbidden OIII emission that has a critical density of about 3.4e10 cm-3.
  In spite of the different origins (inferred from the kinematics of the line
formation region), NV and HeII fluxes are strongly correlated, with the
possible exception of the heaviest accretors.


title:
Magnetic structures of Mn3-xFexSn2: an experimental and theoretical
  study

abstract:
  We investigate the magnetic structure of Mn3-xFexSn2 using neutron powder
diffraction experiments and electronic structure calculations. These alloys
crystallize in the orthorhombic Ni3Sn2 type of structure (Pnma) and comprise
two inequivalent sites for the transition metal atoms (4c and 8d) and two Sn
sites (4c and 4c). The neutron data show that the substituting Fe atoms
predominantly occupy the 4c transition metal site and carry a lower magnetic
moment than Mn atoms. Four kinds of magnetic structures are encountered as a
function of temperature and composition: two simple ferromagnetic structures
(with the magnetic moments pointing along the b or c axis) and two canted
ferromagnetic arrangements (with the ferromagnetic component pointing along the
b or c axis). Electronic structure calculations results agree well with the
low-temperature experimental magnetic moments and canting angles throughout the
series. Comparisons between collinear and non-collinear computations show that
the canted state is stabilized by a band mechanism through the opening of a
hybridization gap. Synchrotron powder diffraction experiments on Mn3Sn2 reveal
a weak monoclinic distortion at low temperature (90.08 deg at 175 K). This
lowering of symmetry could explain the stabilization of the c-axis canted
ferromagnetic structure, which mixes two orthorhombic magnetic space groups, a
circumstance that would otherwise require unusually large high-order terms in
the spin Hamiltonian.


title:
The Chinese Remainder Theorem for strongly semisimple MV-algebras and
  lattice-groups

abstract:
  An MV-algebra (equivalently, a lattice-ordered Abelian group with a
distinguished order unit) is strongly semisimple if all of its quotients modulo
finitely generated congruences are semisimple. All MV-algebras satisfy a
Chinese Reminder Theorem, as was first shown by Keimel four decades ago in the
context of lattice-groups. In this note we prove that the Chinese Remainder
Theorem admits a considerable strengthening for strongly semisimple structures.


title:
Universality of rotons in liquids, generalized superfluidity criterion
  and helons in helium II

abstract:
  An analysis of experimental data shows that, in addition to phonon--roton
excitations in superfluid helium, there necessarily exist at least one branch
of elementary excitations whose energy spectrum strongly depends on
temperature. On this basis, the Landau superfluidity criterion is generalized
for several branches of elementary excitations, taking into account that the
critical velocity should vanish during the phase transition of liquid helium
from the superfluid state to the normal state. We suppose that a new spectrum
of excitations with a gap, depending on interparticle interaction, corresponds
to the transition of helium to superfluid state. This gap exists only in
superfluid state and disappears at the transition temperature to normal state.
The phonon-roton branch of excitations has no crucial influence on
superfluidity. Rotons, as well as phonons, are not the specific excitations for
the superfluid helium, but exist as universal excitations in liquid state, and
form the continuous branch of excitations in different liquids. This point of
view is confirmed experimentally and numerically.


title: BBU effect in an ERL-FEL two-purpose test facility

abstract:
  Both the Energy Recovery Linac (ERL) and Free Electron laser (FEL) are
considered to be candidates of the fourth generation light source. It is
proposed to combine FEL into an ERL facility to integrate the advantages of
both ERL and FEL, and to realize a compact two-purpose light source. A test
facility to verify this principle is being designed at the Institute of High
Energy Physics, Beijing. One main concern is the beam breakup (BBU) instability
which limits the available beam current. To this end, we developed a numerical
simulation code to calculate the BBU threshold, which is found to have only a
small reduction even in a high-FEL-bunch-charge operation mode, compared with
that in the case with ERL bunches only. However, even with ERL beam current far
below BBU threshold, we observed a fluctuation of the central orbit of the ERL
bunches in the presence of FEL beam. We then present a physical model of BBU
and understand the mechanism of the orbit-fluctuation in an ERL-FEL two-purpose
machine. We found that by choosing an appropriate FEL bunch repetition rate,
the central orbit fluctuation amplitude can be well controlled.


title:
Relaxed Sparse Eigenvalue Conditions for Sparse Estimation via
  Non-convex Regularized Regression

abstract:
  Non-convex regularizers usually improve the performance of sparse estimation
in practice. To prove this fact, we study the conditions of sparse estimations
for the sharp concave regularizers which are a general family of non-convex
regularizers including many existing regularizers. For the global solutions of
the regularized regression, our sparse eigenvalue based conditions are weaker
than that of L1-regularization for parameter estimation and sparseness
estimation. For the approximate global and approximate stationary (AGAS)
solutions, almost the same conditions are also enough. We show that the desired
AGAS solutions can be obtained by coordinate descent (CD) based methods.
Finally, we perform some experiments to show the performance of CD methods on
giving AGAS solutions and the degree of weakness of the estimation conditions
required by the sharp concave regularizers.


title: Lifshitz from AdS at finite temperature and top down models

abstract:
  We construct analytically an asymptotically Lifshitz black brane with
dynamical exponent z=1+epsilon^2 in an Einstein-Proca model, where epsilon is a
small parameter. In previous work we showed that the holographic dual QFT is a
deformation of a CFT by the time component of a vector operator and the
parameter epsilon is the corresponding deformation parameter. In the black
brane background this operator additionally acquires a vacuum expectation
value. We explain how the QFT Ward identity associated with Lifshitz invariance
leads to a conserved mass and compute analytically the thermodynamic quantities
showing that they indeed take the form implied by Lifshitz invariance. In the
second part of the paper we consider top down Lifshitz models with dynamical
exponent close to one and show that they can be understood in terms of vector
deformations of conformal field theories. However, in all known cases, both the
conformal field theory and its Lifshitz deformations have modes that violate
the Breitenlohner-Freedman bound.


title:
A covariant action principle for dissipative fluid dynamics: From
  formalism to fundamental physics

abstract:
  We present a new variational framework for dissipative general relativistic
fluid dynamics. The model extends the convective variational principle for
multi-fluid systems to account for a range of dissipation channels. The key
ingredients in the construction are i) the use of a lower dimensional matter
space for each fluid component, and ii) an extended functional dependence for
the associated volume forms. In an effort to make the concepts clear, the
formalism is developed in steps with the model example of matter coupled to
heat considered at each level. Thus we discuss a model for heat flow, derive
the relativistic Navier-Stokes equations and discuss why the individual
dissipative stress tensors need not be spacetime symmetric. We argue that the
new formalism, which notably does not involve an expansion away from an assumed
equilibrium state, provides a conceptual breakthrough in this area of research
and provide an ambitious list of directions in which one may want to extend it
in the future. This involves an exciting set of problems, relating to both
applications and foundational issues.


title:
Correlation between crystal structure and superconductivity in
  LaO0.5F0.5BiS2

abstract:
  Correlation between crystal structure and superconducting properties of the
BiS2-based superconductor LaO0.5F0.5BiS2 was investigated. We have prepared
LaO0.5F0.5BiS2 polycrystalline samples with various lattice constants. It was
found that the annealing the sample under high pressure generated uniaxial
strain along the c axis. Further, the highly-strained sample showed higher
superconducting properties. We concluded that the uniaxial strain along the c
axis was positively linked with the enhancement of superconductivity in the
LaO1-xFxBiS2 system.


title:
Transport properties of a 3D topological insulator based on a strained
  high mobility HgTe film

abstract:
  We investigated the magnetotransport properties of strained, 80nm thick HgTe
layers featuring a high mobility of mu =4x10^5 cm^2/Vs. By means of a top gate
the Fermi-energy is tuned from the valence band through the Dirac type surface
states into the conduction band. Magnetotransport measurements allow to
disentangle the different contributions of conduction band electrons, holes and
Dirac electrons to the conductivity. The results are are in line with previous
claims that strained HgTe is a topological insulator with a bulk gap of ~15meV
and gapless surface states.


title: On the gauge of the natural lineshape

abstract:
  We use a general formulation of nonrelativistic quantum electrodynamics in
which the gauge freedom is carried by the arbitrary transverse component of the
the Green's function for the divergence operator to calculate the natural
lineshape of spontaneous emission, thus discerning the full dependence of the
result on the choice of gauge. We also use a representation of the Hamiltonian
in which the virtual field associated with the atomic ground state is
explicitly absent. We consider two processes by which the atom is excited; the
first is resonant absorption of incident radiation with a sharp line. This
treatment is then adapted to derive a resonance fluorescence rate associated
with the Lamb line in atomic hydrogen. Second we consider the atom's excitation
due to irradiation with a laser pulse treated semi-classically. An experiment
could be used to reveal which of the calculated lineshape distributions is
closest to the measured one. This would provide an answer to a question of
fundamental importance; how does one best describe atom-radiation interactions
with the canonical formalism?


title:
Stable determination of an inclusion in an elastic body by boundary
  measurements (unabridged)

abstract:
  We consider the inverse problem of identifying an unknown inclusion contained
in an elastic body by the Dirichlet-to-Neumann map. The body is made by
linearly elastic, homogeneous and isotropic material. The Lam\'e moduli of the
inclusion are constant and different from those of the surrounding material.
Under mild a-priori regularity assumptions on the unknown defect, we establish
a logarithmic stability estimate. For the proof, we extend the approach used
for electrical and thermal conductors in a novel way. Main tools are
propagation of smallness arguments based on three-spheres inequality for
solutions to the Lam\'e system and refined local approximation of the
fundamental solution of the Lam\'e system in presence of an inclusion.