title:
Damped large amplitude oscillations in a solar prominence and a bundle
  of coronal loops

abstract:
  We investigate the evolutions of two prominences (P1,P2) and two bundles of
coronal loops (L1,L2), observed with SDO/AIA near the east solar limb on 2012
September 22. It is found that there were large-amplitude oscillations in P1
and L1, but no detectable motions in P2 and L2. These transverse oscillations
were triggered by a large-scale coronal wave, originating from a large flare in
a remote active region behind the solar limb. By carefully comparing the
locations and heights of these oscillating and non-oscillating structures, we
conclude that the propagating height of the wave is between 50 Mm and 130 Mm.
The wave energy deposited in the oscillating prominence and coronal loops is at
least of the order of $10^{28}$ erg. Furthermore, local magnetic field strength
and Alfv\'{e}n speeds are derived from the oscillating periods and damping time
scales, which are extracted from the time series of the oscillations. It is
demonstrated that oscillations can be used in not only coronal seismology, but
also revealing the properties of the wave.


title:
Function-Space Based Solution Scheme for the Size-Modified
  Poisson-Boltzmann Equation in Full-Potential DFT

abstract:
  The size-modified Poisson-Boltzmann (MPB) equation is an efficient implicit
solvation model which also captures electrolytic solvent effects. It combines
an account of the dielectric solvent response with a mean-field description of
solvated finite-sized ions. We present a general solution scheme for the MPB
equation based on a fast function-space oriented Newton method and a Green's
function preconditioned iterative linear solver. In contrast to popular
multi-grid solvers this approach allows to fully exploit specialized
integration grids and optimized integration schemes. We describe a
corresponding numerically efficient implementation for the full-potential
density-functional theory (DFT) code FHI-aims. We show that together with an
additional Stern layer correction the DFT+MPB approach can describe the mean
activity coefficient of a KCl aqueous solution over a wide range of
concentrations. The high sensitivity of the calculated activity coefficient on
the employed ionic parameters thereby suggests to use extensively tabulated
experimental activity coefficients of salt solutions for a systematic
parametrization protocol.


title: Decision making via semi-supervised machine learning techniques

abstract:
  Semi-supervised learning (SSL) is a class of supervised learning tasks and
techniques that also exploits the unlabeled data for training. SSL
significantly reduces labeling related costs and is able to handle large data
sets. The primary objective is the extraction of robust inference rules.
Decision support systems (DSSs) who utilize SSL have significant advantages.
Only a small amount of labelled data is required for the initialization. Then,
new (unlabeled) data can be utilized and improve system's performance. Thus,
the DSS is continuously adopted to new conditions, with minimum effort.
Techniques which are cost effective and easily adopted to dynamic systems, can
be beneficial for many practical applications. Such applications fields are:
(a) industrial assembly lines monitoring, (b) sea border surveillance, (c)
elders' falls detection, (d) transportation tunnels inspection, (e) concrete
foundation piles defect recognition, (f) commercial sector companies financial
assessment and (g) image advanced filtering for cultural heritage applications.


title: Lattice models for granular-like velocity fields: Finite-size effects

abstract:
  Long-range spatial correlations in the velocity and energy fields of a
granular fluid are discussed in the framework of a 1d lattice model. The
dynamics of the velocity field occurs through nearest-neighbour inelastic
collisions that conserve momentum but dissipate energy. A set of equations for
the fluctuating hydrodynamics of the velocity and energy mesoscopic fields give
a first approximation for (i) the velocity structure factor and (ii) the
finite-size correction to the Haff law, both in the homogeneous cooling regime.
At a more refined level, we have derived the equations for the two-site
velocity correlations and the total energy fluctuations. First, we seek a
perturbative solution thereof, in powers of the inverse of system size. On the
one hand, when scaled with the granular temperature, the velocity correlations
tend to a stationary value in the long time limit. On the other hand, the
scaled standard deviation of the total energy diverges, that is, the system
shows multiscaling. Second, we find an exact solution for the velocity
correlations in terms of the spectrum of eigenvalues of a certain matrix. The
results of numerical simulations of the microscopic model confirm our
theoretical results, including the above described multiscaling phenomenon.


title: Dead or Alive? Long-term evolution of SN 2015bh (SNhunt275)

abstract:
  Supernova (SN) 2015bh (or SNhunt275) was discovered in NGC 2770 on 2015
February with an absolute magnitude of Mr ~ -13.4 mag, and was initially
classified as a SN impostor. Here we present the photometric and spectroscopic
evolution of SN 2015bh from discovery to late phases (~ 1 yr after). In
addition, we inspect archival images of the host galaxy up to ~ 21 yr before
discovery, finding a burst ~ 1 yr before discovery, and further signatures of
stellar instability until late 2014. Later on, the luminosity of the transient
slowly increases, and a broad light curve peak is reached after about three
months. We propose that the transient discovered in early 2015 could be a
core-collapse SN explosion. The pre-SN luminosity variability history, the
long-lasting rise and faintness first light curve peak suggests that the
progenitor was a very massive, unstable and blue star, which exploded as a
faint SN because of severe fallback of material. Later on, the object
experiences a sudden brightening of 3 mag, which results from the interaction
of the SN ejecta with circumstellar material formed through repeated past
mass-loss events. Spectroscopic signatures of interaction are however visible
at all epochs. A similar chain of events was previously proposed for the
similar interacting SN 2009ip.


title:
SN 2015bh: NGC 2770's 4th supernova or a luminous blue variable on its
  way to a Wolf-Rayet star?

abstract:
  Very massive stars in the final phases of their lives often show
unpredictable outbursts that can mimic supernovae, so-called, "SN impostors",
but the distinction is not always straigthforward. Here we present observations
of a luminous blue variable (LBV) in NGC 2770 in outburst over more than 20
years that experienced a possible terminal explosion as type IIn SN in 2015,
named SN 2015bh. This possible SN or "main event" was preceded by a precursor
peaking $\sim$ 40 days before maximum. The total energy release of the main
event is $\sim$1.8$\times$10$^{49}$ erg, which can be modeled by a $<$ 0.5
M$_\odot$ shell plunging into a dense CSM. All emission lines show a single
narrow P-Cygni profile during the LBV phase and a double P-Cygni profile post
maximum suggesting an association of this second component with the possible
SN. Since 1994 the star has been redder than during a typical S-Dor like
outburst. SN 2015bh lies within a spiral arm of NGC 2770 next to a number of
small star-forming regions with a metallicity of $\sim$ 0.5 solar and a stellar
population age of 7-10 Myr. SN 2015bh shares many similarities with SN 2009ip,
which, together with other examples may form a new class of objects that
exhibit outbursts a few decades prior to "hyper-eruption" or final
core-collapse. If the star survives this event it is undoubtedly altered, and
we suggest that these "zombie stars" may evolve from an LBV to a Wolf Rayet
star over a very short timescale of only a few years. The final fate of these
types of massive stars can only be determined with observations years after the
possible SN.


title:
Comment on: `What Determines the Static Force Chains in Stressed
  Granular Media?'

abstract:
  Comment on O. Gendelman, Y. G. Pollack, I. Procaccia, S. Sengupta, and J.
Zylberg, Physical Review Letters 116, 078001 (2016).


title: Proposal for a tunable graphene-based terahertz Landau-level laser

abstract:
  In the presence of strong magnetic fields the electronic bandstructure of
graphene drastically changes. The Dirac cone collapses into discrete
non-equidistant Landau levels, which can be externally tuned by changing the
magnetic field. In contrast to conventional materials, specific Landau levels
are selectively addressable using circularly polarized light. Exploiting these
unique properties, we propose the design of a tunable laser operating in the
technologically promising terahertz spectral range. To uncover the
many-particle physics behind the emission of light, we perform a fully quantum
mechanical investigation of the non-equilibrium dynamics of electrons, phonons,
and photons in optically pumped Landau-quantized graphene embedded into an
optical cavity. The gained microscopic insights allow us to predict optimal
experimental conditions to realize a technologically promising terahertz laser.


title: Spatial Distribution and Kinematics of OB Stars

abstract:
  The sample of 37 485 suspected OB stars selected by Gontcharov (2008) from
the Tycho-2 catalogue has been cleaned of the stars that are not of spectral
types OV--A0V. For this purpose, the apparent magnitude $V_T$ from Tycho-2, the
absolute magnitude $M_{V_T}$ calibrated as a function of the dereddened color
index $(B_T-V_T)_0$, the interstellar extinction $A_{V_T}$ calculated from the
3D analytical model by Gontcharov (2009) as a function of the Galactic
coordinates, and the photometric distance $r_{ph}$ calculated as a function of
$V_T$, $M_{V_T}$, and $A_{V_T}$ have been reconciled in an iterative process.
The 20 514 stars that passed the iterations have $(B_T-V_T)_0<0$ and
$M_{V_T}>-5$ and are considered as a sample of OV--A0V stars complete within
350 pc of the Sun. Based on the theoretical relation between the dereddened
color and age of the stars, the derived sample has been divided into three
subsamples: $(B_T-V_T)_0<-0.2^m$, $-0.2^m<(B_T-V_T)_0<-0.1^m$, and
$-0.1^m<(B_T-V_T)_0<0^m$, younger than 100, $100-200$, and $200-400$ Myr,
respectively. The spatial distribution of all 20 514 stars and the kinematics
analyzed for more than 1500 stars with radial velocities from the PCRV and RAVE
catalogues are different for the subsamples, showing smooth rotations, shears,
and deformations of the layer of gas producing stars with the formation of the
Gould Belt, the Great Tunnel, the Local Bubble, and other structures within the
last 200 Myr. The detected temporal variations of the velocity dispersions,
solar motion components, Ogorodnikov--Milne model parameters, and Oort
constants are significant, agree with the results of other authors, and show
that it is meaningless to calculate the kinematic parameters for samples of
stars with uncertain ages or with a wide range of ages.


title:
Geometry in Active Learning for Binary and Multi-class Image
  Segmentation

abstract:
  We propose an active learning approach to image segmentation that exploits
geometric priors to speed up and streamline the annotation process. It can be
applied for both background-foreground and multi-class segmentation tasks in 2D
images and 3D image volumes. Our approach combines geometric smoothness priors
in the image space with more traditional uncertainty measures to estimate which
pixels or voxels are the most informative, and thus should to be annotated
next. For multi-class settings, we additionally introduce two novel criteria
for uncertainty. In the 3D case, we use the resulting uncertainty measure to
select voxels lying on a planar patch, which makes batch annotation much more
convenient for the end user compared to the setting where voxels are randomly
distributed in a volume. The planar patch is found using a branch-and-bound
algorithm that looks for a 2D patch in a 3D volume where the most informative
instances are located. We evaluate our approach on Electron Microscopy and
Magnetic Resonance image volumes, as well as on regular images of horses and
faces. We demonstrate a substantial performance increase over other approaches
thanks to the use of geometric priors.


title: Jeans Analysis for Dwarf Spheroidal Galaxies in Wave Dark Matter

abstract:
  Although still under debate, observations generally suggest that dwarf
spheroidal (dSph) galaxies exhibit large constant-density cores in the centers,
which can hardly be explained by dissipationless cold dark matter simulations
without baryonic feedback. Wave dark matter (${\psi {\rm DM}}$), characterized
by a single parameter, the dark matter particle mass $m_{\psi}$, predicts a
central soliton core in every galaxy arising from quantum pressure against
gravity. Here we apply Jeans analysis assuming a soliton core profile to the
kinematic data of eight classical dSphs so as to constrain $m_{\psi}$, and
obtain $m_{\psi}=1.18_{-0.24}^{+0.28}\times10^{-22}{\,\rm eV}$ and
$m_{\psi}=1.79_{-0.33}^{+0.35}\times10^{-22}{\,\rm eV}~(2\sigma)$ using the
observational data sets of Walker et al. (2007) and Walker et al. (2009b),
respectively. We show that the estimate of $m_{\psi}$ is sensitive to the dSphs
kinematic data sets and is robust to various models of stellar density profile.
We also consider multiple stellar subpopulations in dSphs and find consistent
results. This mass range of $m_{\psi}$ is in good agreement with other
independent estimates, such as the high-redshift luminosity functions, the
reionization history, and the Thomson optical depth to the cosmic microwave
background.


title:
Loop suppressed electroweak symmetry breaking and naturally heavy
  superpartners

abstract:
  A model is presented in which O(10 TeV) stop masses, typically required by
the Higgs boson mass in supersymmetric models, do not originate from soft
supersymmetry breaking terms that would drive the Higgs mass squared parameter
to large negative values but rather from the mixing with vectorlike partners.
Their contribution to the Higgs mass squared parameter is reduced to threshold
corrections and, thus, it is one loop suppressed compared to usual scenarios.
New fermion and scalar partners of the top quark with O(10 TeV) masses are
predicted.


title: HERWIRI2.1: Electroweak Corrections for Hadron Scattering

abstract:
  We describe the program HERWIRI2.1, which implements order alpha-squared
photonic radiative corrections exponentiated at the amplitude level (initial
state, final state, and initial-final interference) and electroweak corrections
to the matrix element by generating events using the KK Monte Carlo to generate
the hard process, with quark initial states generated according to PDFs via an
LHAPDF interface. The events can be showered internally using HERWIG6.5 or
exported and showered using any desired external showering program. Some early
results are shown, including comparisons to HERWIG6.5 and HORACE 3.1.


title:
An example of the interplay of nonextensivity and dynamics in the
  description of QCD matter

abstract:
  Using a simple quasi-particle model of QCD matter, presented some time ago in
the literature, in which interactions are modelled by some effective fugacities
z, we investigate the interplay between the dynamical content of fugacities z
and effects induced by nonextensivity in situations when this model is used in
a nonextensive environment characterized by some nonextensive parameter q
$\neq$ 1 (for the usual extensive case q=1). This allows for a better
understanding of the role of nonextensivity in the more complicated
descriptions of dense hadronic and QCD matter recently presented (in which
dynamics is defined by a lagrangian, the form of which is specific to a given
model).


title: N-vicinities method for 3D Ising Model

abstract:
  The n-vicinities method for approximate calculations of the partition
function of a spin system was proposed previously. The equation of state was
obtained in the most general form. In the present publication these results are
adapted to the Ising model on the D-dimensional cubic lattice. The state
equation is solved for an arbitrary dimension D and the behavior of the free
energy is analyzed. For large values of D (D > 2) the obtained results are in
good agreement with the ones obtained by means of computer simulations. For
small values of D (D < 3), there are noticeable discrepancies with the exact
results.


title:
Compositionality, Decompositionality and Refinement in Input/Output
  Conformance Testing - Technical Report

abstract:
  We propose an input/output conformance testing theory utilizing Modal
Interface Automata with Input Refusals (IR-MIA) as novel behavioral formalism
for both the specification and the implementation under test. A modal
refinement relation on IR-MIA allows distinguishing between obligatory and
allowed output behaviors, as well as between implicitly underspecified and
explicitly forbidden input behaviors. The theory therefore supports positive
and negative conformance testing with optimistic and pessimistic environmental
assumptions. We further show that the resulting conformance relation on IR-MIA,
called modal-irioco, enjoys many desirable properties concerning
component-based behaviors. First, modal-irioco is preserved under modal
refinement and constitutes a preorder under certain restrictions which can be
ensured by a canonical input completion for IR-MIA. Second, under the same
restrictions, modal-irioco is compositional with respect to parallel
composition of IR-MIA with multi-cast and hiding. Finally, the quotient
operator on IR-MIA, as the inverse to parallel composition, facilitates
decompositionality in conformance testing to solve the unknown-component
problem.


title:
Nonlinear response of a ballistic graphene transistor with an ac-driven
  gate: high harmonic generation and THz detection

abstract:
  We present results for time-dependent electron transport in a ballistic
graphene field-effect transistor with an ac-driven gate. Nonlinear response to
the ac drive is derived utilizing Floquet theory for scattering states in
combination with Landauer-B\"uttiker theory for transport. We identify two
regimes that can be useful for applications: (i) low and (ii) high doping of
graphene under source and drain contacts, relative to the doping level in the
graphene channel, which in an experiment can be varied by a back gate. In both
regimes, inelastic scattering induced by the ac drive can excite quasi-bound
states in the channel that leads to resonance promotion of higher order
sidebands. Already for weak to intermediate ac drive strength, this leads to a
substantial change in the direct current between source and drain. For strong
ac drive with frequency $\Omega$, we compute the higher harmonics of
frequencies $n\Omega$ ($n$ integer) in the source-drain conductance. In regime
(ii), we show that particular harmonics (for instance $n=6$) can be selectively
enhanced by tuning the doping level in the channel or by tuning the drive
strength. We propose that the device operated in the weak-drive regime can be
used to detect THz radiation, while in the strong-drive regime it can be used
as a frequency multiplier.


title:
Silhouette and spectral line profiles in the special modification of the
  Kerr black hole geometry generated by quintessential fields

abstract:
  We study optical effects in quintessential Kerr black hole spacetimes
corresponding to the limiting case of the equation-of-state parameter
$\omega_{q}=-1/3$ of the quintessence. In dependence on the dimensionless
quintessential field parameter $c$, we determine the black hole silhouette and
the spectral line profiles of Keplerian disks generated in this special
quintessential Kerr geometry, representing an extension of the general
modifications of the Kerr geometry introduced recently by Ghasemi-Nodehi and
Bambi \cite{Gha-Bam:2016:EPJC:}. We demonstrate that due to the influence of
the parameter $c$, the silhouette is almost homogeneously enlarged, and the
spectral line profiles are redshifted with almost conserved shape.


title: Light-by-light scattering in UPC at the LHC

abstract:
  We discuss diphoton semi(exclusive) production in ultraperipheral $PbPb$
collisions at energy of $\sqrt{s_{NN}}=$ 5.5 TeV (LHC). The nuclear
calculations are based on equivalent photon approximation in the impact
parameter space. The cross sections for elementary $\gamma \gamma \to \gamma
\gamma$ subprocess are calculated including two different mechanisms: box
diagrams with leptons and quarks in the loops and a VDM-Regge contribution with
virtual intermediate hadronic excitations of the photons. We got relatively
high cross sections in $PbPb$ collisions ($306$ nb). This opens a possibility
to study the $\gamma \gamma \to \gamma \gamma$ (quasi)elastic scattering at the
LHC. We find that the cross section for elastic $\gamma\gamma$ scattering could
be measured in the lead-lead collisions for the diphoton invariant mass
$W_{\gamma\gamma} \approx 15-20$ GeV.


title:
Lattice simulations with $N_f=2+1$ improved Wilson fermions at a fixed
  strange quark mass

abstract:
  The explicit breaking of chiral symmetry of the Wilson fermion action results
in additive quark mass renormalization. Moreover, flavour singlet and
non-singlet scalar currents acquire different renormalization constants with
respect to continuum regularization schemes. This complicates keeping the
renormalized strange quark mass fixed when varying the light quark mass in
simulations with $N_f=2+1$ sea quark flavours. Here we present and validate our
strategy within the CLS (Coordinated Lattice Simulations) effort to achieve
this in simulations with non-perturbatively order-$a$ improved Wilson fermions.
We also determine various combinations of renormalization constants and
improvement coefficients.


title: Brane involutions on irreducible holomorphic symplectic manifolds

abstract:
  In the context of irreducible holomorphic symplectic manifolds, we say that
(anti)holomorphic (anti)symplectic involutions are brane involutions since
their fixed point locus is a brane in the physicists' language, i.e. a
submanifold which is either complex or lagrangian submanifold with respect to
each of the three K\"ahler structures of the associated hyperk\"ahler
structure.
  Starting from a brane involution on a K3 or abelian surface, one can
construct a natural brane involution on its moduli space of sheaves. We study
these natural involutions and their relation with the Fourier--Mukai transform.
Later, we recall the lattice-theoretical approach to Mirror Symmetry. We
provide two ways of obtaining a brane involution on the mirror and we study the
behaviour of the brane involutions under both mirror transformations, giving
examples in the case of a K3 surface and $K3^{[2]}$-type manifolds.


title: On noncollapsed almost Ricci-flat 4-manifolds

abstract:
  We give topological conditions to ensure that a noncollapsed almost
Ricci-flat 4-manifold admits a Ricci-flat metric. One sufficient condition is
that the manifold is spin and has a nonzero A-hat genus. Another condition is
that the fundamental group is infinite or, more generally, of sufficiently
large cardinality.


title: Bayesian Attack Model for Dynamic Risk Assessment

abstract:
  Because of the threat of advanced multi-step attacks, it is often difficult
for security operators to completely cover all vulnerabilities when deploying
remediations. Deploying sensors to monitor attacks exploiting residual
vulnerabilities is not sufficient and new tools are needed to assess the risk
associated to the security events produced by these sensors. Although attack
graphs were proposed to represent known multi-step attacks occurring in an
information system, they are not directly suited for dynamic risk assessment.
In this paper, we present the Bayesian Attack Model (BAM), a Bayesian
network-based extension to topological attack graphs, capable of handling
topological cycles, making it fit for any information system. Evaluation is
performed on realistic topologies to study the sensitivity of its probabilistic
parameters.


title:
IoT Cloud-based Distribution System State Estimation: Virtual Objects
  and Context-Awareness

abstract:
  This paper presents an IoT cloud-based state estimation system for
distribution networks in which the PMUs (Phasor Measurement Units) are
virtualized with respect to the physical devices. In the considered system only
application level entities are put in the cloud, whereas virtualized PMUs are
running in the communication network edge (i.e. closer to the physical objects)
in order to have a certain degree of local logic, which allows to implement a
bandwidth-efficient and smart data transmission to the involved applications in
the cloud. The major contributions of the paper are the following: we
demonstrate that a cloud-based architecture is capable of achieving the QoS
level required by the specific state estimation application; we show that
implementing a certain local logic for data transmission in the cloud, the
result of the state estimation is not degraded with respect to the case of an
estimation that takes place frequently at fixed intervals; we show the results
in terms of latency and reduced network load for a reference smart grid
network.


title:
Neutron-skin effect and centrality dependence of high-$p_{\mathrm{T}}$
  observables in nuclear collisions

abstract:
  We report on our studies of the neutron-skin effects in high-$p_{\mathrm{T}}$
observables at the LHC. We study the impact of the neutron-skin effect on the
centrality dependence of inclusive direct photon, high-$p_{\mathrm{T}}$ hadron
and $W^{\pm}$ production in nuclear collisions at the LHC. The neutron-skin
effect refers to the observation that in spherical heavy nuclei, the tail of
the neutron distribution extends farther than the distribution of protons,
which can affect observables sensitive to electroweak phenomena in very
peripheral collisions. We quantify this effect for direct photons, charged
hadrons and W bosons as a function of the collision centrality. In the case of
direct photons we find that it will be difficult to resolve the neutron-skin
effect, given the uncertainties in the nuclear PDFs and their spatial
dependence. With charged hadrons and W's, however, up to 20~\% unambiguous
effects are expected for most peripheral collisions.


title:
Transition Region and Chromospheric Signatures of Impulsive Heating
  Events. I. Observations

abstract:
  We exploit the high spatial resolution and high cadence of the Interface
Region Imaging Spectrograph (IRIS) to investigate the response of the
transition region and chromosphere to energy deposition during a small flare.
Simultaneous observations from RHESSI provide constraints on the energetic
electrons precipitating into the flare footpoints while observations of XRT,
AIA, and EIS allow us to measure the temperatures and emission measures from
the resulting flare loops. We find clear evidence for heating over an extended
period on the spatial scale of a single IRIS pixel. During the impulsive phase
of this event the intensities in each pixel for the Si IV 1402.770, C II
1334.535, Mg II 2796.354 and O I 1355.598 emission lines are characterized by
numerous, small-scale bursts typically lasting 60s or less. Red shifts are
observed in Si IV, C II, and Mg II during the impulsive phase. Mg II shows
red-shifts during the bursts and stationary emission at other times. The Si IV
and C II profiles, in contrast, are observed to be red-shifted at all times
during the impulsive phase. These persistent red-shifts are a challenge for
one-dimensional hydrodynamic models, which predict only short-duration
downflows in response to impulsive heating. We conjecture that energy is being
released on many small-scale filaments with a power-law distribution of heating
rates.


title:
Exclusive diffractive production of $\pi^+ \pi^-$ pairs within tensor
  pomeron approach

abstract:
  We discuss exclusive central diffractive production of $\pi^{+} \pi^{-}$ in
proton-(anti)proton collisions at high energies. Based on a tensor pomeron
model we present results of the purely diffractive dipion continuum, the scalar
$f_{0}(500)$, $f_{0}(980)$ and tensor $f_{2}(1270)$ resonances decaying into
the $\pi^{+} \pi^{-}$ pairs as well as the photoproduction mechanism
($\rho^{0}$, Drell-S\"oding). We discuss how two pomerons couple to the tensor
meson $f_{2}(1270)$ and the interference effects of resonance and dipion
continuum contributions. The theoretical results are compared with existing
STAR, CDF, and CMS experimental data. Predictions for planned or being carried
out experiments (ALICE, ATLAS) are presented. We find that the relative
contribution of resonant $f_2(1270)$ and dipion continuum strongly depend on
the cut on proton transverse momenta (or four-momentum transfer squared
$t_{1,2}$) which may explain some controversial observations made by different
ISR experiments in the past. The cuts may play then the role of a $\pi \pi$
resonance filter.


title:
Minimum-latency Time-frequency Analysis Using Asymmetric Window
  Functions

abstract:
  We study the real-time dynamics retrieval from a time series via the
time-frequency (TF) analysis with the minimal latency guarantee. While
different from the well-known intrinsic latency definition in the filter
design, a rigorous definition of intrinsic latency for different time-frequency
representations (TFR) is provided, including the short time Fourier transform
(STFT), synchrosqeezing transform (SST) and reassignment method (RM). To
achieve the minimal latency, a systematic method is proposed to construct an
asymmetric window from a well-designed symmetric one based on the concept of
minimum-phase, if the window satisfies some weak conditions. We theoretically
show that the TFR determined by SST with the constructed asymmetric window does
have a smaller intrinsic latency. Finally, the music onset detection problem is
studied to show the strength of the proposed algorithm.


title:
Asymptotic analysis of noisy fitness maximization, applied to metabolism
  and growth

abstract:
  We consider a population dynamics model coupling cell growth to a diffusion
in the space of metabolic phenotypes as it can be obtained from realistic
constraints-based modelling. In the asymptotic regime of slow diffusion, that
coincides with the relevant experimental range, the resulting non-linear
Fokker-Planck equation is solved for the steady state in the WKB approximation
that maps it into the ground state of a quantum particle in an Airy potential
plus a centrifugal term. We retrieve scaling laws for growth rate fluctuations
and time response with respect to the distance from the maximum growth rate
suggesting that suboptimal populations can have a faster response to
perturbations.

categories: q-bio.PE cond-mat.stat-mech math-ph math.MP


title:
The local detection method: Dynamical detection of quantum discord with
  local operations

abstract:
  Quantum discord in a bipartite system can be dynamically revealed and
quantified through purely local operations on one of the two subsystems. To
achieve this, the local detection method harnesses the influence of initial
correlations on the reduced dynamics of an interacting bipartite system. This
article's aim is to provide an accessible introduction to this method and to
review recent theoretical and experimental progress.


title: New mechanism of radiation polarization in Seyfert-1 AGNs

abstract:
  In most of Seyfert-1 active galactic nucei (AGN) the optical linear continuum
polarization degree is usually small (less than 1%) and the polarization
position angle is nearly parallel to the AGN radio-axis. However, there are
many types-1 AGNs with unexplained intermediate values for both positional
angles and polarization degrees. Our explanation of polarization degree and
positional angle of Seyfert-1 AGNs focuses on the reflection of non-polarized
radiation from sub-parsec jets in optically thick accretion discs. The presence
of a magnetic field surrounding the scattering media will induce Faraday
rotation of the polarization plane that may explain the intermediate values of
positional angles if there is a magnetic field component normal to the
accretion disc. The Faraday rotation depolarization effect in disc diminishes
the competition between polarization of the reflected radiation with the
parallel component of polarization and the perpendicular polarization from
internal radiation of disc (the Milne problem) in favor of polarization of
reflected radiation. This effect allows us to explain the observed polarization
of Seyfert-1 AGN radiation even though the jet optical luminosity is much lower
than the luminosity of disc. We present the calculation of polarization degrees
for a number of Seyfert-1 AGNs.


title: Molecular transport through capillaries made with atomic-scale precision

abstract:
  Nanometre-scale pores and capillaries have long been studied because of their
importance in many natural phenomena and their use in numerous applications. A
more recent development is the ability to fabricate artificial capillaries with
nanometre dimensions, which has enabled new research on molecular transport and
led to the emergence of nanofluidics. But surface roughness in particular makes
it challenging to produce capillaries with precisely controlled dimensions at
this spatial scale. Here we report the fabrication of narrow and smooth
capillaries through van der Waals assembly, with atomically flat sheets at the
top and bottom separated by spacers made of two-dimensional crystals with a
precisely controlled number of layers. We use graphene and its multilayers as
archetypal two-dimensional materials to demonstrate this technology, which
produces structures that can be viewed as if individual atomic planes had been
removed from a bulk crystal to leave behind flat voids of a height chosen with
atomic-scale precision. Water transport through the channels, ranging in height
from one to several dozen atomic planes, is characterized by unexpectedly fast
flow (up to 1 metre per second) that we attribute to high capillary pressures
(about 1,000 bar) and large slip lengths. For channels that accommodate only a
few layers of water, the flow exhibits a marked enhancement that we associate
with an increased structural order in nanoconfined water. Our work opens up an
avenue to making capillaries and cavities with sizes tunable to {\aa}ngstr\"om
precision, and with permeation properties further controlled through a wide
choice of atomically flat materials available for channel walls.


title: Quantum Q systems: From cluster algebras to quantum current algebras

abstract:
  In this paper, we recall our renormalized quantum Q-system associated with
representations of the Lie algebra $A_r$, and show that it can be viewed as a
quotient of the quantum current algebra $U_q({\mathfrak n}[u,u^{-1}])\subset
U_q(\widehat{\mathfrak sl}_2)$ in the Drinfeld presentation. Moreover, we find
the interpretation of the conserved quantities in terms of Cartan currents at
level 0, and the rest of the current algebra, in a non-standard polarization in
terms of generators in the quantum cluster algebra.


title: Triplet Pairing in pure neutron matter

abstract:
  We study the zero temperature BCS gaps for the triplet channel in pure
neutron matter using Similarity Renormalization Group (SRG) evolved
interactions. We use the dependence of the results on the SRG resolution scale,
as a tool to analyze medium and many-body corrections. In particular, we study
the effects of including the three-body interactions at leading order, which
appear at N2LO in the Chiral EFT, as well as that of the first-order
self-energy corrections on the zero temperature gap. In addition we also
extract the transition temperature as a function of densities and verify the
BCS scaling of the zero temperature gaps to the transition temperature. We
observe that the self-energy effects are very crucial in order to reduce the
SRG resolution scale dependence of the results, while the three-body effects at
the leading order do not change the two-body resolution scale dependence. On
the other hand, the results depend strongly on the three-body cut-off,
emphasizing the importance of the missing higher-order three-body effects. We
also observe that self-energy effects reduce the overall gap as well as shift
the gap closure to lower densities.


title: Search for the rare decay $K^+\to\mu^+\nu\bar\nu\nu$

abstract:
  Evidence of the $K^+\to\mu^+\nu\bar\nu\nu$ decay was searched for using E949
experimental data with an exposure of $1.70\times 10^{12}$ stopped kaons. The
data sample is dominated by the backgrond process $K^+\to\mu^+\nu_\mu\gamma$.
An upper limit on the decay rate $\Gamma(K^+\to\mu^+\nu\bar\nu\nu)< 2.4\times
10^{-6}\Gamma(K^+\to all)$ at 90% confidence level was set assuming the
Standard Model muon spectrum. The data are presented in such a way as to allow
calculation of rates for any assumed $\mu^+$ spectrum.


title: Radiatively induced Quark and Lepton Mass Model

abstract:
  We propose a radiatively induced quark and lepton mass model in the first and
second generation with extra $U(1)$ gauge symmetry and vector-like fermions.
Then we analyze the allowed regions which simultaneously satisfy the FCNCs for
the quark sector, LFVs including $\mu-e$ conversion, the quark mass and mixing,
and the lepton mass and mixing. Also we estimate the typical value for the
$(g-2)_\mu$ in our model.


title: Quantum Phase Transition in the Shape of Zr isotopes

abstract:
  The rapid shape change in Zr isotopes near neutron number $N$=60 is
identified to be caused by type II shell evolution associated with massive
proton excitations to its $0g_{9/2}$ orbit, and is shown to be a quantum phase
transition. Monte Carlo shell-model calculations are carried out for Zr
isotopes of $N$=50-70 with many configurations spanned by eight proton orbits
and eight neutron orbits. Energy levels and B(E2) values are obtained within a
single framework in a good agreement with experiments, depicting various shapes
in going from $N$=50 to 70. Novel coexistence of prolate and triaxial shapes is
suggested.


title:
First Measurement of Collectivity of Coexisting Shapes based on Type II
  Shell Evolution: The Case of $^{96}$Zr

abstract:
  Background: Type II shell evolution has recently been identified as a
microscopic cause for nuclear shape coexistence. Purpose: Establish a low-lying
rotational band in 96-Zr. Methods: High-resolution inelastic electron
scattering and a relative analysis of transition strengths are used. Results:
The B(E2; 0_1^+ -> 2_2^+) value is measured and electromagnetic decay strengths
of the secdond 2^+ state are deduced. Conclusions: Shape coexistence is
established for 96-Zr. Type II shell evolution provides a systematic and
quantitative mechanism to understand deformation at low excitation energies.


title: A Distributional Semantics Approach to Implicit Language Learning

abstract:
  In the present paper we show that distributional information is particularly
important when considering concept availability under implicit language
learning conditions. Based on results from different behavioural experiments we
argue that the implicit learnability of semantic regularities depends on the
degree to which the relevant concept is reflected in language use. In our
simulations, we train a Vector-Space model on either an English or a Chinese
corpus and then feed the resulting representations to a feed-forward neural
network. The task of the neural network was to find a mapping between the word
representations and the novel words. Using datasets from four behavioural
experiments, which used different semantic manipulations, we were able to
obtain learning patterns very similar to those obtained by humans.


title: Large linear magnetoresistance from neutral defects in Bi$_2$Se$_3$

abstract:
  The chalcogenide Bi$_2$Se$_3$ can attain the three dimensional (3D) Dirac
semimetal state under the influence of strain and microstrain. Here we report
the presnece of large linear magnetoresistance in such a Bi$_2$Se$_3$ crystal.
The magnetoresistance has quadratic form at low fields which crossovers to
linear above 4 T. The temperature dependence of magnetoresistance scales with
carrier mobility and the crossover field scales with inverse of mobility. Our
analysis suggest that the linear magnetoresistance in our system has a
classical origin and arises from the scattering of high mobility 3D Dirac
electrons from crystalline inhomogeneities. We observe that the charged
selenium vacancies are strongly screened by high mobility Dirac electrons and
the neutral crystalline defects are the main scattering center for transport
mechanism. Our analysis suggests that both the resistivity and the
magnetoresistance have their origin in scattering of charge carriers from
neutral defects.


title: D-modules and complex foliations

abstract:
  Consider a complex analytic manifold $X$ and a coherent Lie subalgebra $\shi$
of the Lie algebra of complex vector fields on $X$. By using a natural
$\shd_X$-module $\shm_\shi$ naturally associated to $\shi$ and the ring (in the
derived sense) $\rhom[\shd_X](\shm_\shi,\shm_\shi)$, we associate integers
which measure the irregularity of the foliation associated with $\shi$.


title:
A note on scaling limits for truncated birth-and-death processes with
  interaction

abstract:
  In this note we consider a Markov chain formed by a finite system of
interacting birth-and-death processes on a finite state space. We study an
asymptotic behaviour of the Markov chain as its state space becomes large. In
particular, we show that the appropriately scaled Markov chain converges to a
diffusion process, and derive conditions for existence of the stationary
distribution of the limit diffusion process in special cases.


title: Anagram-free colorings of graphs

abstract:
  A sequence $S$ is called anagram-free if it contains no consecutive symbols
$r_1 r_2\dots r_k r_{k+1} \dots r_{2k}$ such that $r_{k+1} \dots r_{2k}$ is a
permutation of the block $r_1 r_2\dots r_k$. Answering a question of Erd\H{o}s
and Brown, Ker\"anen constructed an infinite anagram-free sequence on four
symbols.
  Motivated by the work of Alon, Grytczuk, Ha\l uszczak and Riordan, we
consider a natural generalisation of anagram-free sequences for graph
colorings. A coloring of the vertices of a given graph $G$ is called
anagram-free if the sequence of colors on any path in $G$ is anagram-free. We
call the minimal number of colors needed for such a coloring the
anagram-chromatic number of $G$.
  In this paper we study the anagram-chromatic number of several classes of
graphs like trees, minor-free graphs and bounded-degree graphs. Surprisingly,
we show that there are bounded-degree graphs (such as random regular graphs) in
which anagrams cannot be avoided unless we basically give each vertex a
separate color.


title: Mirror dark matter will be confirmed or excluded by XENON1T

abstract:
  Mirror dark matter, where dark matter resides in a hidden sector exactly
isomorphic to the standard model, can be probed via direct detection
experiments by both nuclear and electron recoils if the kinetic mixing
interaction exists. In fact, the kinetic mixing interaction appears to be a
prerequisite for consistent small scale structure: Mirror dark matter halos
around spiral galaxies are dissipative - losing energy via dark photon
emission. This ongoing energy loss requires a substantial energy input, which
can be sourced from ordinary supernovae via kinetic mixing induced processes in
the supernova's core. Astrophysical considerations thereby give a lower limit
on the kinetic mixing strength, and indeed lower limits on both nuclear and
electron recoil rates in direct detection experiments can be estimated. We show
here that potentially all of the viable parameter space will be probed in
forthcoming XENON experiments including LUX and XENON1T. Thus, we anticipate
that these experiments will provide a definitive test of the mirror dark matter
hypothesis.


title: One-dimensional forward-forward mean-field games

abstract:
  While the general theory for the terminal-initial value problem for
mean-field games (MFGs) has achieved a substantial progress, the corresponding
forward-forward problem is still poorly understood - even in the
one-dimensional setting. Here, we consider one-dimensional forward-forward
MFGs, study the existence of solutions and their long-time convergence. First,
we discuss the relation between these models and systems of conservation laws.
In particular, we identify new conserved quantities and study some qualitative
properties of these systems. Next, we introduce a class of wave-like equations
that are equivalent to forward-forward MFGs, and we derive a novel formulation
as a system of conservation laws. For first-order logarithmic forward-forward
MFG, we establish the existence of a global solution. Then, we consider a class
of explicit solutions and show the existence of shocks. Finally, we examine
parabolic forward-forward MFGs and establish the long-time convergence of the
solutions.


title: The complexity of positive semidefinite matrix factorization

abstract:
  Let $A$ be a matrix with nonnegative real entries. The PSD rank of $A$ is the
smallest integer $k$ for which there exist $k\times k$ real PSD matrices
$B_1,\ldots,B_m$, $C_1,\ldots,C_n$ satisfying
$A(i|j)=\operatorname{tr}(B_iC_j)$ for all $i,j$. This paper determines the
computational complexity status of the PSD rank. Namely, we show that the
problem of computing this function is polynomial-time equivalent to the
existential theory of the reals.


title: Making Tree Ensembles Interpretable: A Bayesian Model Selection Approach

abstract:
  Tree ensembles, such as random forests and boosted trees, are renowned for
their high prediction performance. However, their interpretability is
critically limited due to the enormous complexity. In this study, we present a
method to make a complex tree ensemble interpretable by simplifying the model.
Specifically, we formalize the simplification of tree ensembles as a model
selection problem. Given a complex tree ensemble, we aim at obtaining the
simplest representation that is essentially equivalent to the original one. To
this end, we derive a Bayesian model selection algorithm that optimizes the
simplified model while maintaining the prediction performance. Our numerical
experiments on several datasets showed that complicated tree ensembles were
reasonably approximated as interpretable.


title:
Searching for optimal conditions for exploration of double-parton
  scattering in four-jet production at the LHC

abstract:
  We discuss the double-parton scattering (DPS) effects in four-jet production
at the LHC. A special attention is given to the optimization of kinematical
conditions in order to enhance the relative contribution of DPS in four-jet
sample. The calculations of single-parton and double-parton scattering
components are done in the high-energy (or $k_{T}$)-factorization approach.
Here we follow our recent developments of relevant methods and tools that are
implemented in the AVHLIB Monte Carlo library. Several differential
distributions are calculated and carefully discussed in the context of recent
and future searches for DPS effects at the LHC, for both $\sqrt{s} = 7$ and
$13$ TeV energies. The dependences of the relative DPS amount is studied as a
function of rapidity of jets, rapidity distance, and various azimuthal
correlations between jets. The regions with an enhanced DPS contribution are
identified.


title: A universality theorem for nonnegative matrix factorizations

abstract:
  Let $A$ be a matrix with nonnegative real entries. A nonnegative
factorization of size $k$ is a representation of $A$ as a sum of $k$
nonnegative rank-one matrices. The space of all such factorizations is a
bounded semialgebraic set, and we prove that spaces arising in this way are
universal. More presicely, we show that every bounded semialgebraic set $U$ is
rationally equivalent to the set of nonnegative size-$k$ factorizations of some
matrix $A$ up to a permutation of matrices in the factorization. We prove that,
if $U\subset\mathbb{R}^n$ is given as the zero locus of a polynomial with
coefficients in $\mathbb{Q}$, then such a pair $(A,k)$ can be computed in
polynomial time. This result gives a complete description of the algorithmic
complexity of nonnegative rank, and it also allows one to solve the problem of
Cohen and Rothblum on nonnegative factorizations restricted to matrices over
different subfields of $\mathbb{R}$.


title:
Poles of the Standard $\mathcal{L}$-function of $G_2$ and the
  Rallis-Schiffmann Lift

abstract:
  We characterize the cuspidal representations of $G_2$ whose standard
$\mathcal{L}$-function admits a pole at $s=2$ as the image of Rallis-Schiffmann
lift for the commuting pair $\left(\widetilde{SL_2}, G_2\right)$ in
$\widetilde{Sp_{14}}$. The image consists of non-tempered representations. The
main tool is the recent construction, by the second author, of a family of
Rankin-Selberg integrals representing the standard $\mathcal{L}$-function.


title:
Local Convergence of the Heavy-ball Method and iPiano for Non-convex
  Optimization

abstract:
  A local convergence result for abstract descent methods is proved. The
sequence of iterates is attracted by a local (or global) minimum, stays in its
neighborhood and converges within this neighborhood. This result allows
algorithms to exploit local properties of the objective function. In
particular, the abstract theory in this paper applies to the inertial
forward--backward splitting method: iPiano---a generalization of the Heavy-ball
method. Moreover, it reveals an equivalence between iPiano and inertial
averaged/alternating proximal minimization and projection methods. Key for this
equivalence is the attraction to a local minimum within a neighborhood and the
fact that, for a prox-regular function, the gradient of the Moreau envelope is
locally Lipschitz continuous and expressible in terms of the proximal mapping.
In a numerical feasibility problem, the inertial alternating projection method
significantly outperforms its non-inertial variants.


title: Study of semileptonic $\bar{B}^* \to P \ell \bar{\nu}_\ell$ decays

abstract:
  In anticipation of abundant $B^*$ data samples at high-luminosity
heavy-flavor experiments in the future, the tree-dominated semileptonic
$\bar{B}^*_{u,d,s} \to P \ell^- \bar{\nu}_\ell$ $(P=D\,,D_s\,,\pi\,,K)$ decays
are studied within the Standard Model. After a detailed calculation of the
helicity amplitudes, the theoretical predictions for branching fraction~(decay
rate), lepton spin asymmetry, forward-backward asymmetry and ratio
$R_D^{\ast(L)}$ are firstly presented. It is found that the CKM-favored
$\bar{B}^* \to D \ell^- \bar{\nu}_\ell$ decays have relatively large branching
fractions of ${\cal O}(10^{-9})$$\sim$${\cal O}(10^{-7})$, and are in the scope
of running LHC and forthcoming SuperKEKB/Belle-II experiments.


title:
Resolution- and throughput-enhanced spectroscopy using high-throughput
  computational slit

abstract:
  There exists a fundamental tradeoff between spectral resolution and the
efficiency or throughput for all optical spectrometers. The primary factors
affecting the spectral resolution and throughput of an optical spectrometer are
the size of the entrance aperture and the optical power of the focusing
element. Thus far collective optimization of the above mentioned has proven
difficult. Here, we introduce the concept of high-throughput computational
slits (HTCS), a numerical technique for improving both the effective spectral
resolution and efficiency of a spectrometer. The proposed HTCS approach was
experimentally validated using an optical spectrometer configured with a 200 um
entrance aperture, test, and a 50 um entrance aperture, control, demonstrating
improvements in spectral resolution of the spectrum by ~ 50% over the control
spectral resolution and improvements in efficiency of > 2 times over the
efficiency of the largest entrance aperture used in the study while producing
highly accurate spectra.


title: Locally Recoverable codes from rational maps

abstract:
  We give a method to construct Locally Recoverable Error-Correcting codes.
This method is based on the use of rational maps between affine spaces. The
recovery of erasures is carried out by Lagrangian interpolation in general and
simply by one addition in some good cases.


title:
Asymptotics and congruences for partition functions which arise from
  finitary permutation groups

abstract:
  In a recent paper, Bacher and de la Harpe study the conjugacy growth series
of finitary permutation groups. In the course of studying the coefficients of a
series related to the finitary alternating group, they introduce generalized
partition functions $p(n)_{\textbf{e}}$. The group theory motivates the study
of the asymptotics for these functions. Moreover, Bacher and de la Harpe also
conjecture over 200 congruences for these functions which are analogous to the
Ramanujan congruences for the unrestricted partition function $p(n)$. We obtain
asymptotic formulas for all of the $p(n)_{\textbf{e}}$ and prove their
conjectured congruences.


title: Robust Keystroke Biometric Anomaly Detection

abstract:
  The Keystroke Biometrics Ongoing Competition (KBOC) presented an anomaly
detection challenge with a public keystroke dataset containing a large number
of subjects and real-world aspects. Over 300 subjects typed case-insensitive
repetitions of their first and last name, and as a result, keystroke sequences
could vary in length and order depending on the usage of modifier keys. To deal
with this, a keystroke alignment preprocessing algorithm was developed to
establish a semantic correspondence between keystrokes in mismatched sequences.
The method is robust in the sense that query keystroke sequences need only
approximately match a target sequence, and alignment is agnostic to the
particular anomaly detector used. This paper describes the fifteen
best-performing anomaly detection systems submitted to the KBOC, which ranged
from auto-encoding neural networks to ensemble methods. Manhattan distance
achieved the lowest equal error rate of 5.32%, while all fifteen systems
performed better than any other submission. Performance gains are shown to be
due in large part not to the particular anomaly detector, but to preprocessing
and score normalization techniques.


title:
Decentralized Caching Schemes and Performance Limits in Two-layer
  Networks

abstract:
  We study the decentralized caching scheme in a two-layer network, which
includes a sever, multiple helpers, and multiple users. Basically, the proposed
caching scheme consists of two phases, i.e, placement phase and delivery phase.
In the placement phase, each helper/user randomly and independently selects
contents from the server and stores them into its memory. In the delivery
phase, the users request contents from the server, and the server satisfies
each user through a helper. Different from the existing caching scheme, the
proposed caching scheme takes into account the pre-stored contents at both
helpers and users in the placement phase to design the delivery phase.
Meanwhile, the proposed caching scheme exploits index coding in the delivery
phase and leverages multicast opportunities, even when different users request
distinct contents. Besides, we analytically characterize the performance limit
of the proposed caching scheme, and show that the achievable rate region of the
proposed caching scheme lies within constant margins to the
information-theoretic optimum. In particular, the multiplicative and additive
factors are carefully sharpened to be $\frac{1}{48}$ and $4$ respectively, both
of which are better than the state of arts. Finally, simulation results
demonstrate the advantage of the proposed caching scheme compared with the
state of arts.


title:
Impact of charge carrier injection on single-chain photophysics of
  conjugated polymers

abstract:
  Charges in conjugated polymer materials have a strong impact on the
photophysics and their interaction with the primary excited state species has
to be taken into account in understanding device properties. Here, we employ
single-molecule spectroscopy to unravel the influence of charges on several
photoluminescence (PL) observables. The charges are injected either
stochastically by a photochemical process, or deterministically in a
hole-injection sandwich device configuration. We find that upon charge
injection, besides a blue-shift of the PL emission and a shortening of the PL
lifetime due to quenching and blocking of the lowest-energy chromophores, the
non-classical photon arrival time distribution of the multichromophoric chain
is modified towards a more classical distribution. Surprisingly, the fidelity
of photon antibunching deteriorates upon charging, whereas one would actually
expect the number of chromophores to be reduced. A qualitative model is
presented to explain the observed PL changes. The results are of interest to
developing a microscopic understanding of the intrinsic charge-exciton
quenching interaction in devices.


title:
Double resonance response of a superconducting quantum metamaterial:
  manifestation of non-classical states of photons

abstract:
  We report a theoretical study of ac response of superconducting quantum
metamaterials (SQMs), i.e. an array of qubits (two-levels system) embedded in
the low-dissipative resonator. By making use of a particular example of SQM,
namely the array of charge qubits capacitively coupled to the resonator, we
obtain a second-order phase transition between an incoherent (the
high-temperature phase) and coherent (the low-temperatures phase) states of
photons. This phase transition in many aspects resembles the
paramagnetic-ferromagnetic phase transition. The critical temperature of the
phase transition, $T^\star$, is determined by the energy splitting of two-level
systems $\delta$, number of qubits in the array $N$, and the strength of the
interaction $\eta$ between qubits and photons in the cavity. We obtain that the
photon states manifest themselves by resonant drops in the frequency dependent
transmission $D(\omega)$ of electromagnetic waves propagating through a
transmission line weakly coupled to the SQM. At high temperatures the
$D(\omega)$ displays a single resonant drop, and at low temperatures a peculiar
\emph{double resonance response} has to be observed. The physical origin of
such a resonant splitting is the quantum oscillations between two coherent
states of photons of different polarizations.


title: Euler-lagrange equation for a delay variational problem

abstract:
  We establish Euler-Lagrange equations for a problem of Calculus of variations
where the unknown variable contains a term of delay on a segment.


title:
A simplicial foundation for differential and sector forms in tangent
  categories

abstract:
  Tangent categories provide an axiomatic framework for understanding various
tangent bundles and differential operations that occur in differential
geometry, algebraic geometry, abstract homotopy theory, and computer science.
Previous work has shown that one can formulate and prove a wide variety of
definitions and results from differential geometry in an arbitrary tangent
category, including generalizations of vector fields and their Lie bracket,
vector bundles, and connections.
  In this paper we investigate differential and sector forms in tangent
categories. We show that sector forms in any tangent category have a rich
structure: they form a symmetric cosimplicial object. This appears to be a new
result in differential geometry, even for smooth manifolds. In the category of
smooth manifolds, the resulting complex of sector forms has a subcomplex
isomorphic to the de Rham complex of differential forms, which may be
identified with alternating sector forms. Further, the symmetric cosimplicial
structure on sector forms arises naturally through a new equational
presentation of symmetric cosimplicial objects, which we develop herein.


title:
A transformation that preserves principal minors of skew-symmetric
  matrices

abstract:
  Our motivation comes from the work of Engel and Schneider (1980). Their main
theorem implies that two symmetric matrices have equal corresponding principal
minors of all orders if and only if they are diagonally similar. This study was
continued by Hartfiel and Loewy (1984). They found sufficient conditions under
which two $n\times n$ matrices\ $A$ and $B$ have equal corresponding principal
minors of all orders if and only if $B$ or its transpose $B^{t}$ is diagonally
similar to $A$. In this paper, we give a new way to construct a pair of
skew-symmetric having equal corresponding principal minors of all orders.


title:
Formation of homophily in academic performance: students prefer to
  change their friends rather than performance

abstract:
  Homophily, the tendency of individuals to associate with others who share
similar traits, has been identified as a major driving force in the formation
and evolution of social ties. In many cases, it is not clear if homophily is
the result of a socialization process, where individuals change their traits
according to the dominance of that trait in their local social networks, or if
it results from a selection process, in which individuals reshape their social
networks so that their traits match those in the new environment. Here we
demonstrate the detailed temporal formation of strong homophily in academic
achievements of high school and university students. We analyze a unique
dataset that contains information about the detailed time evolution of a
friendship network of 6,000 students across 42 months. Combining the evolving
social network data with the time series of the academic performance (GPA) of
individual students, we show that academic homophily is a result of selection:
students prefer to gradually reorganize their social networks according to
their performance levels, rather than adapting their performance to the level
of their local group. We find no signs for a pull effect, where a social
environment of good performers motivates bad students to improve their
performance. We are able to understand the underlying dynamics of grades and
networks with a simple model. The lack of a social pull effect in classical
educational settings could have important implications for the understanding of
the observed persistence of segregation, inequality and social immobility in
societies.


title:
Some Common Fixed Point Results for Contractive Mappings in Ordered
  G_p-Metric Spaces

abstract:
  In this present article, we get sufficient conditions for the existence and
uniqueness of fixed points and common fixed points for single and double
mapping satisfying various contractive conditions within the partially ordered
0-G_p-complete G_p-metric spaces. Our theorems generalize some fixed point
results existing in the literature. Furthermore, we give some examples
supporting our results.


title:
Demonstration of ultra-broadband single-mode and single-polarization
  operation in T-Guides

abstract:
  Silica-based anchored-membrane waveguides (T-Guides) are fabricated and
characterized from the visible to infrared with streak imaging. It is
numerically shown that the T-Guides can have wideband single-mode and
single-polarization (SMSP) properties over a span of 2.6 octaves.
Experimentally, a polarization-dependent loss difference of up to 90 dB/cm is
measured between orthogonal polarizations, and a record SMSP window of >1.27
octaves is observed, limited only by the available measurement equipment. These
measurements make a strong case for T-Guides for SMSP photonics, particularly
on high-index materials such as our previous demonstration on silicon.


title:
Optimality of the relaxed polar factors by a characterization of the set
  of real square roots of real symmetric matrices

abstract:
  We consider the problem to determine the optimal rotations $R \in {\rm
SO}(n)$ which minimize
  $$W: {\rm SO}(n) \to \mathbb{R}^+_0,\quad W(R\,;D) := ||{\rm sym}(RD -
1)||^2$$ for a given diagonal matrix $D := {\rm diag}(d_1, ..., d_n) \in
\mathbb{R}^{n \times n}$. The function $W$ subject to minimization is the
reduced form of the Cosserat shear-stretch energy, which, in its general form,
is a contribution in any geometrically nonlinear, isotropic and quadratic
Cosserat micropolar (extended) continuum model. We characterize the critical
points of the energy $W(R\,;D)$, determine the global minimizers and the global
minimum. This proves the correctness of previously obtained formulae for the
optimal Cosserat rotations in dimensions two and three. The key to the proof is
a characterization of the entire set of (possibly non-symmetric) real matrix
square roots of (possibly non-positive definite) real symmetric matrices which
does not seem to be known in the literature.


title: Ultraviolet emission from main-sequence companions of AGB stars

abstract:
  Although the majority of known binary Asymptotic Giant Branch (AGB) stars are
symbiotic systems (i.e. with a WD as a secondary star), main-sequence
companions of AGB stars can be more numerous, even though they are more
difficult to find because the primary high luminosity hampers the detection of
the companion at visual wavelengths. However, in the ultraviolet the flux
emitted by a secondary with T eff > 5500 ~ 6000 K may prevail over that of the
primary, and then it can be used to search for candidates to binary AGB stars.
In this work, theoretical atmosphere models are used to calculate the UV excess
in the GALEX near- and far-UV bands due to a main-sequence companion. After
analysing a sample of confirmed binary AGB stars, we propose as a criterium for
binarity: (1) the detection of the AGB star in the GALEX far-UV band and/or (2)
a GALEX near-UV observed-to-predicted flux ratio > 20. These criteria have been
applied to a volume-limited sample of AGB stars within 500 pc of the Sun; 34
out of the sample of 58 AGB stars ( ~ 60%) fulfill them, implying to have a MS
companion of spectral type earlier than K0. The excess in the GALEX near- and
far-UV bands cannot be attributed to a single temperature companion star, thus
suggesting that the UV emission of the secondary might be absorbed by the
extended atmosphere and circumstellar envelope of the primary or that UV
emission is produced in accretion flows.


title:
Rigorous accuracy and robustness analysis for two-scale reduced random
  Kalman filters in high dimensions

abstract:
  Contemporary data assimilation often involves millions of prediction
variables. The classical Kalman filter is no longer computationally feasible in
such a high dimensional context. This problem can often be resolved by
exploiting the underlying multiscale structure, applying the full Kalman
filtering procedures only to the large scale vari- ables, and estimating the
small scale variables with proper statistical strategies, including
multiplicative inflation, representation model error in the observations, and
crude localization. The resulting two-scale reduced filters can have close to
optimal numerical filtering skill based on previous numerical evidence. Yet, no
rigorous explanation exists for this success, because these modifications
create unavoidable bias and model error. This paper contributes to this issue
by establishing a new error analysis framework for two different reduced random
Kalman filters, valid independent of the large dimension. The first part of our
results examines the fidelity of the covariance estimators, which is essential
for accurate uncertainty quantification. In a simplified setting, this is
demonstrated by showing the true error covariance is dominated by its
estimators. In general settings, the Mahalanobis error and its intrinsic
dissipation can indicate covariance fidelity. The second part develops upper
bounds for the covariance estimators by comparing with proper Kalman filters.
Combining both results, the classical tools for Kalman filters can be used as
a-priori performance criteria for the reduced filters. In applications, these
criteria guarantee the reduced filters are robust, and accurate for small noise
systems. They also shed light on how to tune the reduced filters for stochastic
turbulence.


title: Maximal abelian normal subgroups in Nilpotent groups of class 2

abstract:
  A maximal abelian normal subgroup A in a nilpotent group N is
self-centralizing. This makes their role an important one in determining the
structure of the nilpotent group. For example if A is finite then N is also
finite.
  In the free nilpotent group of class 2 such a group is always a cyclic
extension of the center. However this need not be true in an arbitrary finitely
generated class two nilpotent group. We show that three generator nilpotent
groups violating this condition can be easily found. However in the case when
there are four or more generators certain conditions must hold.


title:
Synthetic dimensions in the strong-coupling limit: supersolids and
  pair-superfluids

abstract:
  We study the many-body phases of bosonic atoms with $N$ internal states
confined to a 1D optical lattice under the influence of a synthetic magnetic
field and strong repulsive interactions. The $N$ internal states of the atoms
are coupled via Raman transitions creating the synthetic magnetic field in the
space of internal spin states corresponding to recent experimental
realisations. We focus on the case of strong $\mbox{SU}(N)$ invariant local
density-density interactions in which each site of the 1D lattice is at most
singly occupied, and strong Raman coupling, in distinction to previous work
which has focused on the weak Raman coupling case. This allows us to keep only
a single state per site and derive a low energy effective spin $1/2$ model. The
effective model contains first-order nearest neighbour tunnelling terms, and
second-order nearest neighbour interactions and correlated next-nearest
neighbour tunnelling terms. By adjusting the flux $\phi$ one can tune the
relative importance of first-order and second-order terms in the effective
Hamiltonian. In particular, first-order terms can be set to zero, realising a
novel model with dominant second-order terms. We show that the resulting
competition between density-dependent tunnelling and repulsive density-density
interaction leads to an interesting phase diagram including a phase with
long-ranged pair-superfluid correlations. The method can be straightforwardly
extended to higher dimensions and lattices of arbitrary geometry including
geometrically frustrated lattices where the interplay of frustration,
interactions and kinetic terms is expected to lead to even richer physics.


title:
Effects of magnetic field topology in black hole-neutron star mergers:
  Long-term simulations

abstract:
  We report long-term simulations of black hole-neutron star binary mergers
where the neutron star possesses an asymmetric magnetic field dipole. Focusing
on the scenario where the neutron star is tidally disrupted by the black hole,
we track the evolution of the binary up to $\approx 100$ms after the merger. We
uncover more than one episode of thermally driven winds being launched along a
funnel wall in all these cases beginning from $\approx 25$ms after the merger.
On the other hand, we are unable to conclude presently whether the amount of
ejected mass increases with the \it{degree} of asymmetry. A large-scale
magnetic field configuration in the poloidal direction is formed along the
funnel wall accompanied by the generation of a large Poynting flux. The
magnetic field in the accretion disk around the black hole remnant is amplified
by the nonaxisymmetric magnetorotational instability (MRI). The MRI growth is
estimated to be in the ideal magnetohydrodynamics (MHD) regime and thus would
be free from significant effects induced by potential neutrino radiation.
However, the asymmetry in the magnetic field leads to increased turbulence,
which causes the vertical magnetic field in the accretion disk to grow largely
in a nonlinear manner.


title:
Constraints on neutrino masses from the lensing dispersion of Type Ia
  supernovae

abstract:
  We investigate how accurately the total mass of neutrinos is constrained from
the magnitude dispersion of SNe Ia due to the effects of gravitational lensing.
For this purpose, we use the propagation equation of light bundles in a
realistic inhomogeneous universe and propose a sample selection for supernovae
to avoid difficulties associated with small-scale effects such as strong
lensing or shear effects. With a fitting formula for the nonlinear matter power
spectrum taking account of the effects of massive neutrinos, we find that in
our model it is possible to obtain the upper limit $\Sigma m_{\nu} \simeq
1.0[{\rm eV}]$ for future optical imaging surveys with the Wide-Field InfraRed
Survey Telescope and Large Synoptic Survey Telescope. Furthermore, we discuss
how far we need to observe SNe Ia and to what extent we have to reduce the
magnitude error except for lensing in order to realize the current tightest
limit $\Sigma m_{\nu} < 0.2[{\rm eV}]$.


title: Density of the span of powers of a function \`a la M\"untz-Szasz

abstract:
  The aim of this paper is to establish density properties in $L^p$ spaces of
the span of powers of functions $\{\psi^\lambda\,:\lambda\in\Lambda\}$,
$\Lambda\subset\N$ in the spirit of the M\"untz-Sz\'asz Theorem. As density is
almost never achieved, we further investigate the density of powers and a
modulation of powers $\{\psi^\lambda,\psi^\lambda e^{i\alpha
t}\,:\lambda\in\Lambda\}$. Finally, we establish a M\"untz-Sz\'asz Theorem for
density of translates of powers of cosines
$\{\cos^\lambda(t-\theta\_1),\cos^\lambda(t-\theta\_2)\,:\lambda\in\Lambda\}$.
Under some arithmetic restrictions on $\theta\_1-\theta\_2$, we show that
density is equivalent to a M\"untz-Sz\'asz condition on $\Lambda$ and we
conjecture that those arithmetic restrictions are not needed.Some links are
also established with the recently introduced concept of Heisenberg Uniqueness
Pairs.


title:
An IoT Architecture for Wide Area Measurement Systems: a Virtualized PMU
  Based Approach

abstract:
  Internet of Things (IoT) technologies are pervading different application
domains by relying on sensing and actuating devices that share, process and
present meaningful real-world information. One of the most important of these
domains is certainly the Smart Grid (SG), where the use of advanced measurement
and control equipment and the diffusion of communication technologies are
making an adaptive, reliable, and efficient management of the energy possible,
with several new applications. In this scenario, this paper focuses on one of
the major IoT features, which is the virtualization, and proposes an IoT
solution for wide area measurement systems where virtualized phasor measurement
resources are introduced. Such a solution is intended to make a programmable
and smart environment fostering interoperability, reusability and flexibility
of SG services. The performance of the system is evaluated for both the traffic
generated and the latency to understand which scenarios can benefit from its
deployment.


title: Fracture of dual crosslink gels with permanent and transient crosslinks

abstract:
  We have carried out systematic fracture experiments in a single edge notch
geometry over a range of stretch rates on dual crosslink hydrogels made from
polyvinyl alcohol chains chemically crosslinked with glutaraldehyde and
physically crosslinked with borate ions. If the energy release rate necessary
for crack propagation was calculated conventionally, by using the work done to
deform the sample to the critical value of stretch $\lambda_c$ where the crack
propagates, we found that the fracture energy $\Gamma$ peaks around
$\lambda\sim 0.001 s^{-1}$ before decreasing sharply with increasing stretch
rate, in contradiction with the measurements of crack velocity. Combining
simulations and experimental observations, we propose therefore here a general
method to separate the energy dissipated during loading before crack
propagation, from that which is dissipated during crack propagation. For fast
loading rates (with a characteristic strain rate only slightly lower than the
inverse of the typical breaking time of physical bonds), this improved method
to estimate a local energy release rate $g_{local}$ at the onset of crack
propagation, gives a value of the local fracture energy $\Gamma_{local}$ which
is constant, consistent with the constant value of the crack propagation
velocity measured experimentally. Using this improved method we also obtain the
very interesting result that the dual crosslink gels have a much higher value
of fracture energy at low loading rates than at high loading rates, contrary to
the situation in classical chemically crosslinked elastic networks.


title: Influence of initial fixation position in scene viewing

abstract:
  During scene perception our eyes generate complex sequences of fixations.
Predictors of fixation locations are bottom-up factors like luminance contrast,
top-down factors like viewing instruction, and systematic biases like the
tendency to place fixations near the center of an image. However, comparatively
little is known about the dynamics of scanpaths after experimental manipulation
of specific fixation locations. Here we investigate the influence of initial
fixation position on subsequent eye-movement behavior on an image. We presented
64 colored photographs to participants who started their scanpaths from one of
two experimentally controlled positions in the right or left part of an image.
Additionally, we computed the images' saliency maps and classified them as
balanced images or images with high saliency values on either the left or right
side of a picture. As a result of the starting point manipulation, we found
long transients of mean fixation position and a tendency to overshoot to the
image side opposite to the starting position. Possible mechanisms for the
generation of this overshoot were investigated using numerical simulations of
statistical and dynamical models. We conclude that inhibitory tagging is a
viable mechanism for dynamical planning of scanpaths.


title: Generalized invariants of reflection groups in rank two

abstract:
  For each subgroup of GL_2(F_p) or order divisible by p, generated by
(pseudo-)reflections, we compute the ideals of stable and generalized
invariants. These groups and these ideals are related to the cohomology of
compact Lie groups, Kac-Moody groups and p-compact groups.


title: Full box spaces of free groups

abstract:
  In this paper we investigate full box spaces and coarse equivalences between
them. We do this in two parts. In part one we compare the full box spaces of
free groups on different numbers of generators. In particular the full box
space of a free group $F_k$ is not coarsely equivalent to the full box space of
a free group $F_d$, if $d\ge 8k+10$. In part two we compare
$\Box_f\mathbb{Z}^n$ to the full box spaces of $2$-generated groups. In
particular we prove that the full box space of $\mathbb{Z}^n$ is not coarsely
equivalent to the full box space of any $2$-generated group, if $n\ge 3$.


title: A Proposal for Constraining Initial Vacuum by CMB

abstract:
  We propose a theoretical framework that can possibly constrain the initial
vacuum by Cosmic Microwave Background (CMB) observations. With a generic vacuum
without any particular choice a priori, thereby keeping both the Bogolyubov
coefficients in the analysis, we compute observable parameters from two- and
three-point correlation functions. We are thus left with constraining four
model parameters from the two complex Bogolyubov coefficients. We also
demonstrate a method of finding out the constraint relations between the
Bogolyubov coefficients using the theoretical normalization condition and
observational data of power spectrum and bispectrum from CMB. Finally, we
discuss the possible pros and cons of the analysis.


title: Colorability Saturation Games

abstract:
  We consider the following two-player game: Maxi and Mini start with the empty
graph on $n$ vertices and take turns, always adding one additional edge to the
graph such that the chromatic number is at most $k$, where $k \in \mathbb{N}$
is a given parameter. The game is over when the graph is saturated and no
further edge can be inserted. Maxi wants to maximize the length of the game
while Mini wants to minimize it. The score $s(n,\chi_{>k})$ denotes the number
of edges in the final graph, given that both players followed an optimal
strategy.
  This colorability game belongs to the family of \emph{saturation games} that
are known to provide beautiful and challenging problems despite being defined
via simple combinatorial rules. The analysis of colorability saturation games
has been initiated recently by Hefetz, Krivelevich, Naor, and Stojakovi\'c
(2016). In this paper, we improve their results by providing almost matching
lower and upper bounds on the score of the game that hold for arbitrary choices
of $k$ and $n>k$. In addition, we study the specific game with $k=4$ in more
details and prove that its score is $n^2/3+O(n)$.


title: Search of Secondary Pulsation Modes: Globular cluster (NGC 6496)

abstract:
  The Fourier-discrete-peridogram are used to identify pulsation modes in
variables. We have found two pulsation modes in V1 and V2 among 13 new
variables as described by Abbas et al.. The five variables V9 to V13 are not
shown close to periodic values by analysis of the frequency distribution of
multi-band data and also create difficulty to describe their varied nature. The
multi-band periodic values of V1 and V6 are matched with known literature
values. The scattering of the varied nature of secondary pulsation modes is
eliminated by moving average methodology. The phase curve of secondary mode is
found to be more smooth compared to a prominent mode of pulsation.


title: Modularity of regular and treelike graphs

abstract:
  Clustering algorithms for large networks typically use modularity values to
test which partitions of the vertex set better represent structure in the data.
The modularity of a graph is the maximum modularity of a partition. We consider
the modularity of two kinds of graphs.
  For $r$-regular graphs with a given number of vertices, we investigate the
minimum possible modularity, the typical modularity, and the maximum possible
modularity. In particular, we see that for random cubic graphs the modularity
is usually in the interval $(0.666, 0.804)$, and for random $r$-regular graphs
with large $r$ it usually is of order $1/\sqrt{r}$. These results help to
establish baselines for statistical tests on regular graphs.
  The modularity of cycles and low degree trees is known to be close to 1: we
extend these results to `treelike' graphs, where the product of treewidth and
maximum degree is much less than the number of edges. This yields for example
the (deterministic) lower bound $0.666$ mentioned above on the modularity of
random cubic graphs.

categories: math.CO cond-mat.stat-mech cs.SI physics.soc-ph


title:
Empirical correlation of the surface tension versus the viscosity for
  saturated normal liquids

abstract:
  In 1966 Pelofsky proposed an empirical linear correlation between the natural
logarithm of the surface tension and the reciprocal viscosity, which seems to
work adequately for a wide range of fluids. In particular, it has been shown
that it is useful in the case of n-alkanes and their binary and ternary
mixtures. More recently however, it has been found not to work for several
ionic liquids unless the reciprocal viscosity is raised to a power. The
exponent of this power was fixed to be 0.3, at least for the studied ionic
fluids. In the present work, the performance and accuracy of both the original
Pelofsky correlation and the modified expression including the exponent are
studied for 56 non-ionic fluids of different kinds over a broad range of
temperatures. Also, the temperature range is delimited for which each
expression reproduces the surface tension values with average absolute
deviations below 1%. The needed coefficients are given for both the broad and
the delimited temperature range for each expression. Unfortunately, the results
show that the value of the exponent in the modified Pelofsky expression is
substance-dependent for the normal fluids studied.


title:
Nonzero radial solutions for elliptic systems with coupled functional
  BCs in exterior domains

abstract:
  We prove new results on the existence, non-existence, localization and
multiplicity of nontrivial radial solutions of a system of elliptic boundary
value problems on exterior domains subject to nonlocal, nonlinear, functional
boundary conditions. Our approach relies on fixed point index theory. As a
by-product of our theory we provide an answer to an open question posed by do
{\'O}, Lorca, S\'{a}nchez and Ubilla. We include some examples with explicit
nonlinearities in order to illustrate our theory.


title:
Dynamic Elastic Moduli in Magnetic Gels: Normal Modes and Linear
  Response

abstract:
  In the perspective of developing smart hybrid materials with customized
features, ferrogels and magnetorheological elastomers allow a synergy of
elasticity and magnetism. The interplay between elastic and magnetic properties
gives rise to a unique reversible control of the material behavior by applying
an external magnetic field. Albeit few works have been performed on the
time-dependent properties so far, understanding the dynamic behavior is the key
to model many practical situations, e.g. applications as vibration absorbers.
Here we present a way to calculate the frequency-dependent elastic moduli based
on the decomposition of the linear response to an external stress in normal
modes. We use a minimal three-dimensional dipole-spring model to theoretically
describe the magnetic and elastic interactions on the mesoscopic level.
Specifically, the magnetic particles carry permanent magnetic dipole moments
and are spatially arranged in a prescribed way, before they are linked by
elastic springs. An external magnetic field aligns the magnetic moments. On the
one hand, we study regular lattice-like particle arrangements to compare with
previous results in the literature. On the other hand, we calculate the dynamic
elastic moduli for irregular, more realistic particle distributions. Our
approach measures the tunability of the linear dynamic response as a function
of the particle arrangement, the system orientation with respect to the
external magnetic field, as well as the magnitude of the magnetic interaction
between the particles. The strength of the present approach is that it
explicitly connects the relaxational modes of the system with the rheological
properties as well as with the internal rearrangement of the particles in the
sample, providing new insight into the dynamics of these remarkable materials.


title:
New correlations between viscosity and surface tension for saturated
  normal fluids

abstract:
  New correlations between viscosity and surface tension are proposed and
checked for saturated normal fluids. The proposed correlations contain three or
four adjustable coefficients for every fluid. They were obtained by fitting 200
data points, ranging from the triple point to a point very near to the critical
one. Forty substances were considered, including simple fluids (such as rare
gases), simple hydrocarbons, refrigerants, and some other substances such as
carbon dioxide and water. Two correlation models with three adjustable
coefficients were checked, and the results showed that the one based on the
modified Pelofsky expression gives the better overall results. A new
4-coefficient correlation is then proposed which clearly improves the results,
giving the lowest overall deviations for 32 out of the 40 substances considered
and absolute average deviations below 10% for all of them.


title:
A new trace bilinear form on cyclic $\mathbb{F}_q$-linear
  $\mathbb{F}_{q^t}$-codes

abstract:
  Let $\mathbb{F}_q$ be a finite field of cardinality $q$, where $q$ is a power
of a prime number $p$, $t\geq 2$ an even number satisfying $t \not\equiv 1
\;(\bmod \;p)$ and $\mathbb{F}_{q^t}$ an extension field of $\mathbb{F}_q$ with
degree $t$. First, a new trace bilinear form on $\mathbb{F}_{{q^t}}^n$ which is
called $\Delta$-bilinear form is given, where $n$ is a positive integer coprime
to $q$. Then according to this new trace bilinear form, bases and enumeration
of cyclic $\Delta$-self-orthogonal and cyclic $\Delta$-self-dual
$\mathbb{F}_q$-linear $\mathbb{F}_{q^t}$-codes are investigated when $t=2$.
Furthermore, some good $\mathbb{F}_q$-linear $\mathbb{F}_{q^2}$-codes are
obtained.


title:
How many subsets of edges of a directed multigraph can be represented as
  trails?

abstract:
  For each subset of edges of a (directed multi-) graph, one may determine
whether the edges can be represented as a trail. I prove that the fraction
trail-representable subsets of edges is at most $O(\sqrt{\log m}/\sqrt{m})$,
where $m$ is the number of edges, and show by example that the upper bound is
nearly tight.


title:
Improved Correlation for Viscosity from Surface Tension Data for
  Saturated Normal Fluids

abstract:
  Several correlations between viscosity and surface tension for saturated
normal fluids have been proposed in the literature. Usually, they include three
or four adjustable coefficients for every fluid and give generally good
results. In this paper we propose a new and improved four-coefficient
correlation which was obtained by fitting data ranging from the triple point to
a point very near to the critical one. Fifty four substances were considered,
including simple fluids (such as rare gases), simple hydrocarbons,
refrigerants, and some other substances such as carbon dioxide, water or
ethanol. The new correlation clearly improves the results obtained with those
previously available since it gives absolute average deviations below1% for 40
substances and below 2.1% for 10 substances more.


title:
A transfer-operator-based relation between Laplace eigenfunctions and
  zeros of Selberg zeta functions

abstract:
  Over the last few years Pohl (partly jointly with coauthors) developed dual
`slow/fast' transfer operator approaches to automorphic functions, resonances,
and Selberg zeta functions for a certain class of hyperbolic surfaces
$\Gamma\backslash\mathbb{H}$ with cusps and all finite-dimensional unitary
representations $\chi$ of $\Gamma$.
  The eigenfunctions with eigenvalue $1$ of the fast transfer operators
determine the zeros of the Selberg zeta function for $(\Gamma,\chi)$. Further,
if $\Gamma$ is cofinite and $\chi$ is the trivial one-dimensional
representation then highly regular eigenfunctions with eigenvalue $1$ of the
slow transfer operators characterize Maass cusp forms for $\Gamma$.
Conjecturally, this characterization extends to more general automorphic
functions as well as to residues at resonances.
  In this article we study, without relying on Selberg theory, the relation
between the eigenspaces of these two types of transfer operators for any Hecke
triangle surface $\Gamma\backslash\mathbb{H}$ of finite or infinite area and
any finite-dimensional unitary representation $\chi$ of the Hecke triangle
group $\Gamma$. In particular we provide explicit isomorphisms between relevant
subspaces. This solves a conjecture by M\"oller and Pohl, characterizes some of
the zeros of the Selberg zeta functions independently of the Selberg trace
formula, and supports the previously mentioned conjectures.


title:
Synthesis of Strategies Using the Hoare Logic of Angelic and Demonic
  Nondeterminism

abstract:
  We study a propositional variant of Hoare logic that can be used for
reasoning about programs that exhibit both angelic and demonic nondeterminism.
We work in an uninterpreted setting, where the meaning of the atomic actions is
specified axiomatically using hypotheses of a certain form. Our logical
formalism is entirely compositional and it subsumes the non-compositional
formalism of safety games on finite graphs. We present sound and complete
Hoare-style calculi that are useful for establishing partial-correctness
assertions, as well as for synthesizing implementations. The computational
complexity of the Hoare theory of dual nondeterminism is investigated using
operational models, and it is shown that the theory is complete for exponential
time.


title: Robust adaptive strategies for the guidance of users in road networks

abstract:
  We present an algorithm for optimal guidance of users in road networks. It is
a "stochastic-on-time-arrival (SOTA)"-like algorithm which calculates optimal
guidance strategies with reliable paths, for road network origin-destination
pairs. Our contribution consists here in extending an existing SOTA algorithm,
in order to include robustness of the guidance strategy, towards path failures.
The idea of SOTA algorithms is to calculate the maximum probability of reaching
a destination node, starting from any node of a road network, and given a time
budget. This calculus gives the optimal path for every origin-destination pair
of nodes in the network, with an associated optimal adaptive guidance strategy.
We propose here an extension of this approach in order to take into account the
existence and the performance of alternative detours of the selected paths, in
the calculus of the guidance strategy. We take into account the fact that one
or many links of the selected optimal path may fail during the travel. We then
consider that users may be sensitive to path changing. That is to say that they
may prefer paths with efficient alternative detours, with respect to paths
without, or with less efficient detours, even with a loss in the average travel
time, and/or in its reliability. In order to take into account such behaviors,
we propose a model that includes the existence as well as the performance of
detours for selected paths, in the calculus of the travel time reliability.
This new way of calculating travel time reliability guarantees a kind of
robustness of the guidance strategies.


title:
Electron and hole doping in the relativistic Mott insulator
  Sr$_2$IrO$_4$: a first-principles study using band unfolding technique

abstract:
  We study the effects of dilute La and Rh doping on the electronic structure
of the relativistic Mott insulator Sr$_2$IrO$_4$ using fully relativistic and
magnetically non-collinear density functional theory with the inclusion of an
on-site Hubbard $U$. To model doping effects, we have adopted the supercell
approach that allows for a realistic treatment of structural relaxations and
electronic effects beyond a purely rigid band approach. By means of the band
unfolding technique we have computed the spectral function and constructed the
effective band structure and Fermi surface (FS), which are readily comparable
with available experimental data. Our calculations clearly indicate that La and
Rh doping can be interpreted as effective electron and (fractional) hole
doping, respectively. In Sr$_{2-x}$La$_x$IrO$_4$ the IMT is accompanied by a
moderate renormalization of the electronic correlation substantiated by a
reduction of the effective on-site Coulomb repulsion $U-J$ from 1.6 eV ($x=0$)
to 1.4 eV (metallic regime $x=12.5\%$). The progressive closing of the
relativistic Mott gap leads to the emergence of connected elliptical electron
pockets at ($\pi$/2,$\pi$/2) and less intense features at $X$ in the FS. The
substitution of Ir with the nominally isovalent Rh is accompanied by a
substantial hole transfer from the Rh site to the nearest neighbor Ir sites.
This shifts down the chemical potential, creates almost circular disconnected
hole pockets in the FS and establishes the emergence of a two-dimensional
metallic state formed by conducting Rh-planes intercalated by insulating
Ir-planes. Finally, our data indicate that hole doping causes a flipping of the
in-plane net ferromagnetic moment in the Rh plane and induces a magnetic
transition from the AF-I to the AF-II ordering.


title:
Construction and shape optimization of simplicial meshes in
  $d$-dimensional space

abstract:
  We provide a constructive proof of a face-to-face simplical partition of a
d-dimensional space for arbitrary d by generalizing the idea of Sommerville,
used to create space-filling tetrahedra out of triangular base, to any
dimension. Each step of construction that increases the dimension is determined
up to a positive parameter, d-dimensional simplical partition is therefore
parametrized by d parameters. We show the shape optimal value of those
parameters.


title:
The SERMON project: 48 new field Blazhko stars and an investigation of
  modulation-period distribution

abstract:
  We investigated 1234 fundamental mode RR Lyrae stars observed by the All Sky
Automated Survey (ASAS) to identify the Blazhko (BL) effect. A sample of 1547
BL stars from the literature was collected to compare the modulation-period
distribution with stars newly identified in our sample. A classical frequency
spectra analysis was performed using Period04 software. Data points from each
star from the ASAS database were analysed individually to avoid confusion with
artificial peaks and aliases. Statistical methods were used in the
investigation of the modulation-period distribution. Altogether we identified
87 BL stars (48 new detections), 7 candidate stars, and 22 stars showing
long-term period variations. The distribution of modulation periods of newly
identified BL stars corresponds well to the distribution of modulation periods
of stars located in the Galactic field, Galactic bulge, Large Magellanic Cloud,
and globular cluster M5 collected from the literature. As a very important
by-product of this comparison, we found that pulsation periods of BL stars
follow Gaussian distribution with the mean period of $0.54\pm0.07$ d, while the
modulation periods show log-normal distribution with centre at $\log(P_{\rm
m}~{\rm [d]})=1.78\pm0.30$ dex. This means that 99.7 % of all known modulated
stars have BL periods between 7.6 and 478 days. We discuss the identification
of long modulation periods and show, that a significant percentage of stars
showing long-term period variations could be classified as BL stars.