title: Smooth projected density estimation

abstract:
  We introduce and analyse a new nonparametric estimator of a multi-dimensional
density. Our smooth projection estimator (SPE) is defined by a least squares
projection of the sample onto an infinite dimensional mixture class via an
undersmoothed nonparametric pilot estimate, which acts as a structural filter
to regularise the solution. The undersmoothing is required to optimise the
convergence rate of the SPE, which is jointly determined by that of the pilot
estimator to the true density in squared $\mathbb{L}_{2}$ norm, and by that of
the pilot distribution function to the empirical distribution function in
uniform norm. Our procedure was conceived with a view to exploiting well known
results in convex analysis and their connection to mixture densities. In the
context of our work, this translates to the observation that the infinite
dimensional minimisation problem, implicit in the construction of the SPE,
possesses a solution of dimension at most $n+1$, where $n$ is the sample size.
The SPE thus enjoys practical advantages such as computational efficiency, ease
of storage and rapid evaluation at a new data point.


title: Topological superconducting phase in helical Shiba chains

abstract:
  Recently, it has been suggested that topological superconductivity and
Majorana end states can be realized in a chain of magnetic impurities on the
surface of an s-wave superconductor when the magnetic moments form a spin helix
as a result of the RKKY interaction mediated by the superconducting substrate.
Here, we investigate this scenario theoretically by developing a tight-binding
Bogoliubov-de Gennes description starting from the Shiba bound states induced
by the individual magnetic impurities. While the resulting model Hamiltonian
has similarities with the Kitaev model for one-dimensional spinless p-wave
superconductors, there are also important differences, most notably the
long-range nature of hopping and pairing as well as the complex hopping
amplitudes. We use both analytical and numerical approaches to explore the
consequences of these differences for the phase diagram and the localization
properties of the Majorana end states when the Shiba chain is in a topological
superconducting phase.


title:
Dipole Anisotropy in Integrated Linearly Polarized Flux Density in NVSS
  Data

abstract:
  We study the dipole anisotropy in integrated linearly polarization flux
density in NRAO VLA Sky Survey (NVSS). We extract the anisotropy parameters in
the number counts, number counts weighted by polarization observables, i.e.
degree of polarization (p) and polarization flux (P). We also determine the
anisotropy in the degree of polarization per source and polarization flux per
source. We consider data with several different cuts on the flux density,
S>10,20,30,40,50 mJy. For studies with degree of polarization we impose the
additional cut 0.01<p<1. Similarly for polarization flux we impose, 0.5<P<100
mJy. We find a very significant signal of dipole, both in number counts and P
(or p) weighted number counts. For the case of P weighted number counts the
significance ranges from 8 \sigma to 5 \sigma for S>20 mJy to S>50 mJy. The
corresponding direction parameters are found to be stable with the cut on flux
density. The significance is even higher for the case of p weighted number
counts. The observed anisotropy is found to be much larger in comparison to the
CMBR expectations. We find that polarization observables show a much higher
level of anisotropy in comparison to pure number counts or flux weighted number
counts.


title: Thermal Width of Quarkonium from Holography

abstract:
  From the AdS/CFT correspondence, the effects of charge and finite 't Hooft
coupling correction on the thermal width of a heavy quarkonium are
investigated. To study the charge effect, we consider Maxwell charge which is
interpreted as quark medium. In the case of finite 't Hooft coupling
corrections, $\mathcal{R}^4$ terms and Gauss-Bonnet gravity have been
considered, respectively. It is shown that these corrections affect the thermal
width. It is also argued that by decreasing the 't Hooft coupling, the thermal
width becomes effectively smaller. Interestingly, this is similar to analogous
calculations in weakly coupled plasma.


title: Numerical semigroups, cyclotomic polynomials and Bernoulli numbers

abstract:
  We give two proofs of a folkore result relating numerical semigroups of
embedding dimension two and binary cyclotomic polynomials and explore some
consequences. In particular, we give a more conceptual reproof of a result of
Hong et al. (2012) on gaps between the exponents of non-zero monomials in a
binary cyclotomic polynomial.
  The intent of the author with this expositional paper is to better unify the
various results within the cyclotomic polynomial and numerical semigroup
communities.


title: Modifications of torsion-free coherent analytic sheaves

abstract:
  We study the transformation of torsion-free coherent analytic sheaves under
proper modifications. More precisely, we study direct images of inverse image
sheaves, and torsion-free preimages of direct image sheaves. Under some
conditions, it is shown that torsion-free coherent sheaves can be realized as
the direct image of locally free sheaves under modifications. Thus, it is
possible to study coherent sheaves modulo torsion by reducing the problem to
study vector bundles on manifolds. We apply this to reduced ideal sheaves and
to the Grauert-Riemenschneider canonical sheaf of holomorphic n-forms.


title:
Molecular dynamics (MD) calculation of the zeta potential of neutral
  surfaces

abstract:
  Molecular dynamics (MD) simulations of the zeta potential are so poor that it
has become common to term their predictions 'apparent'. Here we demonstrate how
zeta potentials that agree with measured values can be calculated by: (1)
integrating the net average charge in surface-parallel layers from the midpoint
of the fluid layer (where the electrostatic potential is zero) to and then into
two solid caps, (2) determining the position of slipping plane with separate
Couette flow models, and (3) calculating the charge distribution and
electrostatic potential under static conditions. The solids we model are charge
neutral surfaces composed of atoms with zero charge or charge balanced
monovalent or divalent ions. The zeta potentials calculated are within a few
millivolts of measured values, and the measured values fall within the
simulation error bars. Insights provided by the improved MD simulations into
the complex phenomena that affect surface charge and zeta potential are
discussed.


title: The fractional Cheeger problem

abstract:
  Given an open and bounded set $\Omega\subset\mathbb{R}^N$, we consider the
problem of minimizing the ratio between the $s-$perimeter and the
$N-$dimensional Lebesgue measure among subsets of $\Omega$. This is the
nonlocal version of the well-known Cheeger problem. We prove various properties
of optimal sets for this problem, as well as some equivalent formulations. In
addition, the limiting behaviour of some nonlinear and nonlocal eigenvalue
problems is investigated, in relation with this optimization problem. The
presentation is as self-contained as possible.


title: Pulsar scattering in space and time

abstract:
  We report on a recent global VLBI experiment in which we study the scatter
broadening of pulsars in the spatial and time domain simultaneously. Depending
on the distribution of scattering screen(s), geometry predicts that the less
spatially broadened parts of the signal arrive earlier than the more broadened
parts. This means that over one pulse period the size of the scattering disk
should grow from pointlike to the maximum size. An equivalent description is
that the pulse profile shows less temporal broadening on the longer baselines.
This contribution presents first results that are consistent with the expected
expanding rings. We also briefly discuss how the autocorrelations can be used
for amplitude calibration. This requires a thorough investigation of the
digitisation and the sampler statistics and is not fully solved yet.


title:
The equations of the inverse kinematics problem and scheme of its
  solution

abstract:
  In the article derived and checked differential equations that solve the
problem of reconstructing the motion parameters of a rigid frame of reference
if known proper acceleration and angular velocity of its origin as a function
of proper time. These equations are based on the known transformation to an
arbitrary rigid non-inertial reference frame, which generalizes the Lorentz
transformation, takes into account the fact of his proper Thomas precession and
form of the metric arbitrary frame of reference. Role this the problem in the
physics is that all such frames which have the same characteristics will have
the same properties.


title: Timing of Pathogen Adaptation to a Multicomponent Treatment

abstract:
  The sustainable use of multicomponent treatments such as combination
therapies, combination vaccines/chemicals, and plants carrying multigenic
resistance requires an understanding of how their population-wide deployment
affects the speed of the pathogen adaptation. Here, we develop a stochastic
model describing the emergence of a mutant pathogen and its dynamics in a
heterogeneous host population split into various types by the management
strategy. Based on a multi-type Markov birth and death process, the model can
be used to provide a basic understanding of how the life-cycle parameters of
the pathogen population, and the controllable parameters of a management
strategy affect the speed at which a pathogen adapts to a multicomponent
treatment. Our results reveal the importance of coupling stochastic mutation
and migration processes, and illustrate how their stochasticity can alter our
view of the principles of managing pathogen adaptive dynamics at the population
level. In particular, we identify the growth and migration rates that allow
pathogens to adapt to a multicomponent treatment even if it is deployed on only
small proportions of the host. In contrast to the accepted view, our model
suggests that treatment durability should not systematically be identified with
mutation cost. We show also that associating a multicomponent treatment with
defeated monocomponent treatments can be more durable than associating it with
intermediate treatments including only some of the components. We conclude that
the explicit modelling of stochastic processes underlying evolutionary dynamics
could help to elucidate the principles of the sustainable use of multicomponent
treatments in population-wide management strategies intended to impede the
evolution of harmful populations.


title:
Discovery of a planetary nebula surrounding the symbiotic star DT
  Serpentis

abstract:
  We report the discovery of a planetary nebula centered on the poorly studied
symbiotic binary star DT Ser. In a few other symbiotic stars spatially resolved
nebulae have been discovered: however, only one of them might be a genuine
planetary nebula, while the others are likely to originate in complex mass
ejections episodes from the interacting binary central stars, possibly related
to nova-like outbursts. The rim of the planetary nebula around DT Ser is
severely distorted toward a brighter star, 5 arcsec away. In infrared WISE
data, this star shows the presence of a detached cold dust shell such as those
observed in post-AGB stars. The apparent association of the symbiotic star and
its planetary nebula with the nearby possible post-AGB object is discussed. We
also discuss the sparse and conflicting literature data that could support an
observed variability of the surface brightness of the planetary nebula. The
puzzling and intriguing characteristics displayed by DT Ser are surely worth
further and more detailed investigations.


title:
SALT long-slit spectroscopy of LBQS 2113-4538: variability of the Mg II
  and Fe II component

abstract:
  The Mg II line is of extreme importance in intermediate redshift quasars
since it allows us to measure the black hole mass in these sources and to use
these sources as probes of the distribution of dark energy in the Universe, as
a complementary tool to SN Ia. Reliable use of Mg II requires a good
understanding of all the systematic effects involved in the measurement of the
line properties, including the contamination by Fe II UV emission. We performed
three spectroscopic observations of a quasar LBQS 2113-4538 (z = 0.956) with
the SALT telescope separated in time by several months and we analyze in detail
the mean spectrum and the variability in the spectral shape. We show that even
in our good-quality spectra the Mg II doublet is well fit by a single
Lorentzian shape. We tested several models of the Fe II pseudo-continuum and
showed that one of them well represents all the data. The amplitudes of both
components vary in time, but the shapes do not change significantly. The
measured line width of LBQS 2113-4538 identifies this object as a class A
quasar. The upper limit of $3\%$ for the contribution of the Narrow Line Region
(NLR) to Mg II may suggest that the separation of the Broad Line Region (BLR)
and NLR disappears in this class of objects.


title: Simulation of Self-Pulsing in Kerr-Nonlinear Coupled Ring Resonators

abstract:
  Nonlinear resonant structures consisting of coupled ring resonators can be
modeled by difference-differential equations that take into account
non-instantaneous Kerr response and the effect of loss. We present a simple and
efficient numerical formalism for solution of the system and calculation of the
time evolution. The technique is demonstrated by investigating the dynamical
behavior of the coupled structure with two rings, namely, focusing on
self-pulsing solutions. The influence of both, loss and non-instantaneous Kerr
response, is also presented.


title: Independence properties in subalgebras of ultraproduct II$_1$ factors

abstract:
  Let $M_n$ be a sequence of finite factors with $\dim(M_n)\rightarrow \infty$
and denote $\text{\bf M}=\Pi_\omega M_n$ their ultraproduct over a free
ultrafilter $\omega$. We prove that if $\text{\bf Q}\subset \text{\bf M}$ is
either an ultraproduct $\text{\bf Q}=\Pi_\omega Q_n$ of subalgebras $Q_n\subset
M_n$, with $Q_n \not\prec_{M_n} Q_n'\cap M_n$, $\forall n$, or the centralizer
$\text{\bf Q}=B'\cap \text{\bf M}$ of a separable amenable *-subalgebra
$B\subset \text{\bf M}$, then for any separable subspace $X\subset \text{\bf
M}\ominus (\text{\bf Q}'\cap \text{\bf M})$, there exists a diffuse abelian von
Neumann subalgebra in $\text{\bf Q}$ which is {\it free independent} to $X$,
relative to $\text{\bf Q}'\cap \text{\bf M}$. Some related independence
properties for subalgebras in ultraproduct II$_1$ factors are also discussed.


title:
Applications of closed models defined by counting to graph theory and
  topology

abstract:
  In this paper, we define the notion of closed models defined by counting, and
we compute their homotopy categories. We apply this construction to various
categories of graphs. We show that there does not exist a closed model in the
category of undirected graphs which characterizes the Ihara Zeta function in
the sense that, a morphism $f:X\rightarrow Y$ is a weak equivalence for this
model if and only if it induces a bijection between the sets of non degenerated
cycles of $X$ and $Y$. Finally, we apply our construction to Galoisian
complexes and dessins d'enfant.


title: Domain-wall free energy in Heisenberg ferromagnets

abstract:
  We consider Gaussian fluctuations about domain walls embedded in one- or
two-dimensional spin lattices. Analytic expressions for the free energy of one
domain wall are obtained. From these, the temperature dependence of
experimentally relevant spatial scales -- i.e., the correlation length for spin
chains and the size of magnetic domains for thin films magnetized out of plane
-- are deduced. Stability of chiral order inside domain walls against thermal
fluctuations is also discussed.


title:
Remarks on criteria for achieving the optimal diversity-multiplexing
  gain trade-off

abstract:
  In this short note we will prove that non-vanishing determinant (NVD)
criterion is not enough for an asymmetric space-time block code (STBC) to
achieve the optimal diversity-multiplexing gain trade-off (DMT). This result is
in contrast to the recent result made by Srinath and Rajan. In order to clarify
the issue further the approximately universality criterion by Tavildar and
Viswanath is translated into language of lattice theory and some conjectures
are given.


title: High multiplicity W+jets predictions at NLO

abstract:
  In these proceedings we present results from a recent calculation for the
production of a W boson in conjunction with five jets at next-to-leading order
in perturbative QCD. We also use results at lower multiplicities to extrapolate
the cross section to the same process with six jets.


title: Cop and robber game and hyperbolicity

abstract:
  In this note, we prove that all cop-win graphs G in the game in which the
robber and the cop move at different speeds s and s' with s'<s, are
\delta-hyperbolic with \delta=O(s^2). We also show that the dependency between
\delta and s is linear if s-s'=\Omega(s) and G obeys a slightly stronger
condition. This solves an open question from the paper (J. Chalopin et al., Cop
and robber games when the robber can hide and ride, SIAM J. Discr. Math. 25
(2011) 333-359). Since any \delta-hyperbolic graph is cop-win for s=2r and
s'=r+2\delta for any r>0, this establishes a new - game-theoretical -
characterization of Gromov hyperbolicity. We also show that for weakly modular
graphs the dependency between \delta and s is linear for any s'<s. Using these
results, we describe a simple constant-factor approximation of the
hyperbolicity \delta of a graph on n vertices in O(n^2) time when the graph is
given by its distance-matrix.


title:
Featureless quantum spin liquid, 1/3-magnetization plateau state and
  exotic thermodynamic properties of spin-1/2 frustrated Heisenberg
  antiferromagnet on an infinite Husimi lattice

abstract:
  By utilizing tensor-network-based methods, we investigate the zero- and
finite-temperature properties of the spin-1/2 Heisenberg antiferromagnetic
(HAF) model on an infinite Husimi lattice that contains 3/2 sites per triangle.
The ground state of this model is found to possess vanishing local
magnetization and is featureless; the spin-spin and dimer-dimer correlation
functions are verified to decay exponentially; and its ground-state energy per
site is determined to be $e_0=-0.4343(1)$, which is very close to that
[$e_0=-0.4386(5)$] of the intriguing kagome HAF model. The magnetization curve
shows the absence of a zero-magnetization plateau, implying a gapless
excitation. A $1/3$-magnetization plateau with spin up-up-down state is
observed, which is selected and stabilized by quantum fluctuations. A ground
state phase diagram under magnetic fields is presented. Moreover, both magnetic
susceptibility and the specific heat are studied, whose low-temperature
behaviors reinforce the conclusion that the HAF model on the infinite Husimi
lattice owns a gapless and featureless spin liquid ground state.


title:
Dynamical bar-mode instability in rotating and magnetized relativistic
  stars

abstract:
  We present three-dimensional simulations of the dynamical bar-mode
instability in magnetized and differentially rotating stars in full general
relativity. Our focus is on the effects that magnetic fields have on the
dynamics and the onset of the instability. In particular, we perform
ideal-magnetohydrodynamics simulations of neutron stars that are known to be
either stable or unstable against the purely hydrodynamical instability, but to
which a poloidal magnetic field in the range of $10^{14}$--$10^{16}$ G is
superimposed initially. As expected, the differential rotation is responsible
for the shearing of the poloidal field and the consequent linear growth in time
of the toroidal magnetic field. The latter rapidly exceeds in strength the
original poloidal one, leading to a magnetic-field amplification in the the
stars. Weak initial magnetic fields, i.e. $ \lesssim 10^{15}$ G, have
negligible effects on the development of the dynamical bar-mode instability,
simply braking the stellar configuration via magnetic-field shearing, and over
a timescale for which we derived a simple algebraic expression. On the other
hand, strong magnetic fields, i.e. $\gtrsim 10^{16}$ G, can suppress the
instability completely, with the precise threshold being dependent also on the
amount of rotation. As a result, it is unlikely that very highly magnetized
neutron stars can be considered as sources of gravitational waves via the
dynamical bar-mode instability.


title: Fundamental stellar properties from asteroseismology

abstract:
  Accurate characterization of stellar populations is of prime importance to
correctly understand the formation and evolution process of our Galaxy. The
field of asteroseismology has been particularly successful in such an endeavor
providing fundamental parameters for large samples of stars in different
evolutionary phases. We present our results on determinations of masses, radii,
and distances of stars in the CoRoT and Kepler fields, showing that we can map
and date different regions of the galactic disk and distinguish gradients in
the distribution of stellar properties at different heights. We further review
how asteroseismic determinations can produce a unique set of constraints,
including ages, outside the solar neighborhood for galactic chemical evolution
models.


title: A classical long-time tail in a driven granular fluid

abstract:
  I derive a mode-coupling theory for the velocity autocorrelation function,
\psi(t), in a fluid of randomly driven inelastic hard spheres far from
equilibrium. With this, I confirm a conjecture from simulations that the
velocity autocorrelation function decays algebraically, \psi(t) ~ t^{-3/2}, if
momentum is conserved. I show that the slow decay is due to the coupling to
transverse currents.


title:
Equivalence of minimal time and minimal norm control problems for
  semilinear heat equations

abstract:
  In this paper, we establish the equivalence of minimal time and minimal norm
control problems for semilinear heat equations in which the controls are
distributed internally in an open subset of the state domain. As an
application, the Bang-Bang property for minimal norm controls are also
presented.


title:
Lattice bosons in a quasi-disordered environment: The effects of
  next-nearest-neighbor hopping on localization and Bose-Einstein condensation

abstract:
  We present a theoretical study of the effects of the next-nearest-neighbor
(NNN) hopping ($t_2$) on the properties of non-interacting bosons in optical
lattices in the presence of an Aubry-Andr\'{e} quasi-disorder. First we
investigate, employing exact diagonalization, the effects of $t_2$ on the
localization properties of a single boson. The localization is monitored using
an entanglement measure as well as with inverse participation ratio. We find
that the sign of $t_2$ has a significant influence on the localization effects.
We also provide analytical results in support of the trends found in the
localization behavior. Further, we extend these results including the effects
of a harmonic potential which obtains in experiments. Next, we study the
effects of $t_2$ on Bose-Einstein condensation. We find that, a positive $t_2$
strongly enhances the low temperature thermal depletion of the condensate while
a negative $t_2$ reduces it. It is also found that, for a fixed temperature,
increasing the quasi-disorder strength reduces the condensate fraction in the
extended regime while enhancing it in the localized regime. We also investigate
the effects of boundary conditions and that of the phase of the AA potential on
the condensate. These are found to have significant effects on the condensate
fraction in the localization transition region.


title:
From nonlinear to linearized elasticity via Gamma-convergence: the case
  of multiwell energies satisfying weak coercivity conditions

abstract:
  Linearized elasticity models are derived, via Gamma-convergence, from
suitably rescaled nonlinear energies when the corresponding energy densities
have a multiwell structure and satisfy a weak coercivity condition, in the
sense that the typical quadratic bound from below is replaced by a weaker p
bound, 1<p <2, away from the wells. This study is motivated by, and our results
are applied to, energies arising in the modeling of nematic elastomers.


title:
A Comparison of Hybridized and Standard DG Methods for Target-Based
  hp-Adaptive Simulation of Compressible Flow

abstract:
  We present a comparison between hybridized and non-hybridized discontinuous
Galerkin methods in the context of target-based hp-adaptation for compressible
flow problems. The aim is to provide a critical assessment of the computational
efficiency of hybridized DG methods. Hybridization of finite element
discretizations has the main advantage, that the resulting set of algebraic
equations has globally coupled degrees of freedom only on the skeleton of the
computational mesh. Consequently, solving for these degrees of freedom involves
the solution of a potentially much smaller system. This not only reduces
storage requirements, but also allows for a faster solution with iterative
solvers. Using a discrete-adjoint approach, sensitivities with respect to
output functionals are computed to drive the adaptation. From the error
distribution given by the adjoint-based error estimator, h- or p-refinement is
chosen based on the smoothness of the solution which can be quantified by
properly-chosen smoothness indicators. Numerical results are shown for
subsonic, transonic, and supersonic flow around the NACA0012 airfoil.
hp-adaptation proves to be superior to pure h-adaptation if discontinuous or
singular flow features are involved. In all cases, a higher polynomial degree
turns out to be beneficial. We show that for polynomial degree of approximation
p=2 and higher, and for a broad range of test cases, HDG performs better than
DG in terms of runtime and memory requirements.


title: Reachability Problem for Weak Multi-Pushdown Automata

abstract:
  This paper is about reachability analysis in a restricted subclass of
multi-pushdown automata. We assume that the control states of an automaton are
partially ordered, and all transitions of an automaton go downwards with
respect to the order. We prove decidability of the reachability problem, and
computability of the backward reachability set. As the main contribution, we
identify relevant subclasses where the reachability problem becomes
NP-complete. This matches the complexity of the same problem for
communication-free vector addition systems, a special case of stateless
multi-pushdown automata.


title:
Vibronic Excitation Dynamics in Orbitally Degenerate Correlated Electron
  System

abstract:
  Orbital-lattice coupled excitation dynamics in orbitally degenerate
correlated systems are examined. We present a theoretical framework, where both
local vibronic excitations and superexchange-type inter-site interactions are
dealt with on an equal footing. We generalize the spin-wave approximation so as
to take local vibronic states into account. Present method is valid from weak
to strong Jahn-Teller coupling magnitudes. Two characteristic excitation modes
coexist; a low-energy dispersive mode and high-energy multi-peak mode. These
are identified as a collective vibronic mode, and Flanck-Condon excitations in
a single Jahn-Teller center modified by the inter-site interactions,
respectively. Present formalism covers vibronic dynamics in several
orbital-lattice coupled systems.


title:
Relativistic corrections to the pair double heavy diquark production in
  e^+e^- annihilation

abstract:
  On the basis of perturbative QCD and relativistic quark model we calculate
relativistic and bound state corrections in the production processes of a pair
of double heavy diquarks. Relativistic factors in the production amplitude
connected with the relative motion of heavy quarks and the transformation law
of the bound state wave function to the reference frame of the moving diquark
S-wave bound states are taken into account. For the gluon and quark propagators
entering the production vertex function we use a truncated expansion in the
ratio of the relative quark momenta to the center-of-mass energy s up to the
second order. Relativistic corrections to the quark-quark bound state wave
functions in the rest frame are considered by means of the Breit-like
potential. It turns out that examined effects change essentially
nonrelativistic results of the cross sections. The estimate of the yield of
pairs of double heavy baryons (ccq) at the B-factory is presented.


title: Polynomial graph invariants from homomorphism numbers

abstract:
  We give a method of generating strongly polynomial sequences of graphs, i.e.,
sequences $(H_{\mathbf{k}})$ indexed by a multivariate parameter
$\mathbf{k}=(k_1,\ldots, k_h)$ such that, for each fixed graph $G$, there is a
multivariate polynomial $p(G;x_1,\ldots, x_h)$ such that the number of
homomorphisms from $G$ to $H_{\mathbf{k}}$ is given by the evaluation
$p(G;k_1,\ldots, k_h)$. A classical example is the sequence $(K_k)$ of complete
graphs, for which ${\rm hom}(G,K_k)=P(G;k)$ is the evaluation of the chromatic
polynomial at $k$. Our construction produces a large family of graph
polynomials that includes the Tutte polynomial, the Averbouch-Godlin-Makowsky
polynomial and the Tittmann-Averbouch-Makowsky polynomial. We also introduce a
new graph parameter, the {\em branching core size} of a simple graph, related
to how many involutive automorphisms with fixed points it has. We prove that a
countable family of graphs of bounded branching core size (which in particular
implies bounded tree-depth) is always contained in a finite union of strongly
polynomial sequences.


title: On the rigidity of nematic liquid crystal flow on $S^2$

abstract:
  In this paper we establish the uniformity property of a simplified
Ericksen-Leslie system modelling the hydrodynamics of nematic liquid crystals
on the two dimensional unit sphere $S^2$, namely the uniform convergence in
$L^2$ to a steady state exponentially as t tends to infinity. The main
assumption, similar to Topping [15], concerns the equation of liquid crystal
director $d$ and states that at infinity time, a weak limit $d_\infty$ and any
bubble $\omega_i$($1\le i\le l$) share a common orientation. As consequences,
the uniformity property holds under various types of small initial data.


title: Is superhydrophobicity robust with respect to disorder?

abstract:
  We consider theoretically the Cassie-Baxter and Wenzel states describing the
wetting contact angles for rough substrates. More precisely, we consider
different types of periodic geometries such as square protrusions and disks in
2D, grooves and nanoparticles in 3D and derive explicitly the contact angle
formulas. We also show how to introduce the concept of surface disorder within
the problem and, inspired by biomimetism, study its effect on
superhydrophobicity. Our results, quite generally, prove that introducing
disorder, at fixed given roughness, will lower the contact angle: a disordered
substrate will have a lower contact angle than a corresponding periodic
substrate. We also show that there are some choices of disorder for which the
loss of superhydrophobicity can be made small, making superhydrophobicity
robust.


title: Topological bifurcations in a model society of reasonable contrarians

abstract:
  People are often divided into conformists and contrarians, the former tending
to align to the majority opinion in their neighborhood and the latter tending
to disagree with that majority. In practice, however, the contrarian tendency
is rarely followed when there is an overwhelming majority with a given opinion,
which denotes a social norm. Such reasonable contrarian behavior is often
considered a mark of independent thought, and can be a useful strategy in
financial markets.
  We present the opinion dynamics of a society of reasonable contrarian agents.
The model is a cellular automaton of Ising type, with antiferromagnetic pair
interactions modeling contrarianism and plaquette terms modeling social norms.
We introduce the entropy of the collective variable as a way of comparing
deterministic (mean-field) and probabilistic (simulations) bifurcation
diagrams.
  In the mean field approximation the model exhibits bifurcations and a chaotic
phase, interpreted as coherent oscillations of the whole society. However, in a
one-dimensional spatial arrangement one observes incoherent oscillations and a
constant average.
  In simulations on Watts-Strogatz networks with a small-world effect the mean
field behavior is recovered, with a bifurcation diagram that resembles the
mean-field one, but using the rewiring probability as the control parameter.
Similar bifurcation diagrams are found for scale free networks, and we are able
to compute an effective connectivity for such networks.


title:
Macroscopic locality with equal bias reproduces with high fidelity a
  quantum distribution achieving the Tsirelson's bound

abstract:
  Two physical principles, Macroscopic Locality (ML) and Information Causality
(IC), so far, have been most successful in distinguishing quantum correlations
from post-quantum correlations. However, there are also some post-quantum
probability distributions which cannot be distinguished with the help of these
principles. Thus, it is interesting to see whether consideration of these two
principles, separately, along with some additional physically plausible
constraints, can explain some interesting quantum features which are otherwise
hard to reproduce. In this paper we show that, in a Bell-CHSH scenario, ML
along with constraint of equal-biasness for the concerned observables, almost
reproduces the quantum joint probability distribution corresponding to maximal
quantum Bell violation, which is unique up to relabeling. From this example and
earlier work of Cavalcanti, Salles and Scarani, we conclude that IC and ML are
in-equivalent physical principles; satisfying one does not imply that the other
is satisfied.


title: A balanced k-means algorithm for weighted point sets

abstract:
  The classical $k$-means algorithm for partitioning $n$ points in
$\mathbb{R}^d$ into $k$ clusters is one of the most popular and widely spread
clustering methods. The need to respect prescribed lower bounds on the cluster
sizes has been observed in many scientific and business applications.
  In this paper, we present and analyze a generalization of $k$-means that is
capable of handling weighted point sets and prescribed lower and upper bounds
on the cluster sizes. We call it weight-balanced $k$-means. The key difference
to existing models lies in the ability to handle the combination of weighted
point sets with prescribed bounds on the cluster sizes. This imposes the need
to perform partial membership clustering, and leads to significant differences.
  For example, while finite termination of all $k$-means variants for
unweighted point sets is a simple consequence of the existence of only finitely
many partitions of a given set of points, the situation is more involved for
weighted point sets, as there are infinitely many partial membership
clusterings. Using polyhedral theory, we show that the number of iterations of
weight-balanced $k$-means is bounded above by $n^{O(dk)}$, so in particular it
is polynomial for fixed $k$ and $d$. This is similar to the known worst-case
upper bound for classical $k$-means for unweighted point sets and unrestricted
cluster sizes, despite the much more general framework. We conclude with the
discussion of some additional favorable properties of our method.


title:
Multilevel Summation for Dispersion: A Linear-Time Algorithm for
  $r^{-6}$ Potentials

abstract:
  We have extended the multilevel summation (MLS) method, originally developed
to evaluate long-range Coulombic interactions in molecular dynamics (MD)
simulations [Skeel et al., J. Comput. Chem., 23, 673 (2002)], to handle
dispersion interactions. While dispersion potentials are formally short-ranged,
accurate calculation of forces and energies in interfacial and inhomogeneous
systems require long-range methods. The MLS method offers some significant
advantages compared to the particle-particle particle-mesh and smooth particle
mesh Ewald methods. Unlike mesh-based Ewald methods, MLS does not use fast
Fourier transforms and is thus not limited by communication and bandwidth
concerns. In addition, it scales linearly in the number of particles, as
compared with the $\mathcal{O}(N \log N)$ complexity of the mesh-based Ewald
methods. While the structure of the MLS method is invariant for different
potentials, every algorithmic step had to be adapted to accommodate the
$r^{-6}$ form of the dispersion interactions. In addition, we have derived
error bounds, similar to those obtained by Hardy for the electrostatic MLS
[Hardy, Ph.D. thesis, University of Illinois at Urbana-Champaign (2006)]. Using
a prototype implementation, we have demonstrated the linear scaling of the MLS
method for dispersion, and present results establishing the accuracy and
efficiency of the method.


title: The oriented graph complexes

abstract:
  Oriented graph complexes, in which graphs are not allowed to have oriented
cycles, govern for example the quantization of Lie bialgebras and infinite
dimensional deformation quantization. It is shown that the oriented graph
complex GC^or_n is quasi-isomorphic to the ordinary commutative graph complex
GC_{n-1}, up to some known classes. This yields in particular a combinatorial
description of the action of the Grothendieck-Teichm\"uller Lie algebra on Lie
bialgebras, and shows that a cycle-free formality morphism in the sense of
Shoikhet can be constructed rationally without reference to configuration space
integrals.


title: Cross Ratios of Quadrilateral Linkages

abstract:
  We discuss the cross-ratio map of planar quadrilateral linkages, also in the
case when one of the links is telescopic. Most of our results are valid for a
planar quadrilateral linkage with generic lengths of the sides. In particular,
we describe the image of cross-ratio map for quadrilateral linkage and planar
robot 3-arm.


title:
A Literature Survey of Benchmark Functions For Global Optimization
  Problems

abstract:
  Test functions are important to validate and compare the performance of
optimization algorithms. There have been many test or benchmark functions
reported in the literature; however, there is no standard list or set of
benchmark functions. Ideally, test functions should have diverse properties so
that can be truly useful to test new algorithms in an unbiased way. For this
purpose, we have reviewed and compiled a rich set of 175 benchmark functions
for unconstrained optimization problems with diverse properties in terms of
modality, separability, and valley landscape. This is by far the most complete
set of functions so far in the literature, and tt can be expected this complete
set of functions can be used for validation of new optimization in the future.


title: Irreducible projective characters of wreath products

abstract:
  The irreducible character values of the spin wreath products of the symmetric
group and an arbitrary finite group are completely determined.


title: CN excitation and electron densities in diffuse molecular clouds

abstract:
  Utilising previous work by the authors on the spin-coupled rotational
cross-sections for electron-CN collisions, data for the associated rate
coefficients is presented. Data on rotational, fine-structure and
hyperfine-structure transition involving rotational levels up to $N$=20 are
computed for temperatures in the range 10 -- 1000~K. Rates are calculated by
combining Born-corrected R-matrix calculations with the infinite-order-sudden
(IOS) approximation. The dominant hyperfine transitions are those with $\Delta
N=\Delta j= \Delta F=1$. For dipole-allowed transitions, electron-impact rates
are shown to exceed those for excitation of CN by para-H$_2$($j=0$) by five
orders of magnitude. The role of electron collisions in the excitation of CN in
diffuse clouds, where local excitation competes with the cosmic microwave
background (CMB) photons, is considered. Radiative transfer calculations are
performed and the results compared to observations. These comparisons suggest
that electron density lies in the range $n(e)\sim 0.01-0.06$~cm$^{-3}$ for
typical physical conditions present in diffuse clouds.


title:
Using Modularity Metrics to assist Move Method Refactoring of Large
  System

abstract:
  For large software systems, refactoring activities can be a challenging task,
since for keeping component complexity under control the overall architecture
as well as many details of each component have to be considered. Product
metrics are therefore often used to quantify several parameters related to the
modularity of a software system. This paper devises an approach for
automatically suggesting refactoring opportunities on large software systems.
We show that by assessing metrics for all components, move methods refactoring
an be suggested in such a way to improve modularity of several components at
once, without hindering any other. However, computing metrics for large
software systems, comprising thousands of classes or more, can be a time
consuming task when performed on a single CPU. For this, we propose a solution
that computes metrics by resorting to GPU, hence greatly shortening computation
time. Thanks to our approach precise knowledge on several properties of the
system can be continuously gathered while the system evolves, hence assisting
developers to quickly assess several solutions for reducing modularity issues.


title:
Insight into the skew-scattering mechanism of the spin Hall effect:
  potential scattering versus spin-orbit scattering

abstract:
  We present a detailed analysis of the skew-scattering contribution to the
spin Hall conductivity using an extended version of the resonant scattering
model of Fert and Levy [Phys. Rev. Lett. {\bf 106}, 157208 (2011)]. For $5d$
impurities in a Cu host, the proposed phase shift model reproduces the
corresponding first-principles calculations. Crucial for that agreement is the
consideration of two scattering channels related to $p$ and $d$ impurity
states, since the discussed mechanism is governed by a subtle interplay between
the spin-orbit and potential scattering in both angular-momentum channels. It
is shown that the potential scattering strength plays a decisive role for the
magnitude of the spin Hall conductivity.


title: Incentives for Privacy Tradeoff in Community Sensing

abstract:
  Community sensing, fusing information from populations of privately-held
sensors, presents a great opportunity to create efficient and cost-effective
sensing applications. Yet, reasonable privacy concerns often limit the access
to such data streams. How should systems valuate and negotiate access to
private information, for example in return for monetary incentives? How should
they optimally choose the participants from a large population of strategic
users with privacy concerns, and compensate them for information shared? In
this paper, we address these questions and present a novel mechanism,
SeqTGreedy, for budgeted recruitment of participants in community sensing. We
first show that privacy tradeoffs in community sensing can be cast as an
adaptive submodular optimization problem. We then design a budget feasible,
incentive compatible (truthful) mechanism for adaptive submodular maximization,
which achieves near-optimal utility for a large class of sensing applications.
This mechanism is general, and of independent interest. We demonstrate the
effectiveness of our approach in a case study of air quality monitoring, using
data collected from the Mechanical Turk platform. Compared to the state of the
art, our approach achieves up to 30% reduction in cost in order to achieve a
desired level of utility.


title: Epidemic Spreading on Weighted Complex Networks

abstract:
  Nowadays, the emergence of online services provides various multi-relation
information to support the comprehensive understanding of the epidemic
spreading process. In this Letter, we consider the edge weights to represent
such multi-role relations. In addition, we perform detailed analysis of two
representative metrics, outbreak threshold and epidemic prevalence, on SIS and
SIR models. Both theoretical and simulation results find good agreements with
each other. Furthermore, experiments show that, on fully mixed networks, the
weight distribution on edges would not affect the epidemic results once the
average weight of whole network is fixed. This work may shed some light on the
in-depth understanding of epidemic spreading on multi-relation and weighted
networks.


title: Jacob's Ladder and Scientific Ontologies

abstract:
  The main goal of this article is to use the epistemological framework of a
specific version of Cognitive Constructivism to address Piaget's central
problem of knowledge construction, namely, the re-equilibration of cognitive
structures. The distinctive objective character of this constructivist
framework is based on Heinz von Foerster's fundamental metaphor of - objects as
tokens for eigen-solutions, and is also supported by formal inference methods
of Bayesian statistics. This epistemological perspective is illustrated using
some episodes in the history of chemistry concerning the definition or
identification of chemical elements. Some of von Foerster's epistemological
imperatives provide general guidelines of development and argumentation.


title: Strings in compact cosmological spaces

abstract:
  We confront the problem of giving a fundamental definition to perturbative
string theory in spacetimes with totally compact space (taken to be a torus for
simplicity, though the nature of the problem is very general) and non-compact
time. Due to backreaction induced by the presence of even a single string
quantum, the usual formulation of perturbative string theory in a fixed
classical background is infrared-divergent at all subleading orders in the
string coupling, and needs to be amended. The problem can be seen as a closed
string analogue of D0-brane recoil under an impact by closed strings (a
situation displaying extremely similar infrared divergences). Inspired by the
collective coordinate treatment of the D0-brane recoil, whereby the
translational modes of the D0-brane are introduced as explicit dynamical
variables in the path integral, we construct a similar formalism for the case
of string-induced gravitational backreaction, in which the spatially uniform
modes of the background fields on the compact space are quantized explicitly.
The formalism can equally well be seen as an ultraviolet completion of a
minisuperspace quantum cosmology with string degrees of freedom. We consider
the amplitudes for the universe to have two cross-sections with specified
spatial properties and string contents, and show (at the first non-trivial
order) that they are finite within our formalism.


title:
A Study on Stroke Rehabilitation through Task-Oriented Control of a
  Haptic Device via Near-Infrared Spectroscopy-Based BCI

abstract:
  This paper presents a study in task-oriented approach to stroke
rehabilitation by controlling a haptic device via near-infrared
spectroscopy-based brain-computer interface (BCI). The task is to command the
haptic device to move in opposing directions of leftward and rightward
movement. Our study consists of data acquisition, signal preprocessing, and
classification. In data acquisition, we conduct experiments based on two
different mental tasks: one on pure motor imagery, and another on combined
motor imagery and action observation. The experiments were conducted in both
offline and online modes. In the signal preprocessing, we use localization
method to eliminate channels that are irrelevant to the mental task, as well as
perform feature extraction for subsequent classification. We propose multiple
support vector machine classifiers with a majority-voting scheme for improved
classification results. And lastly, we present test results to demonstrate the
efficacy of our proposed approach to possible stroke rehabilitation practice.


title: Preconditioned Random Toeplitz Operators

abstract:
  The solution of Hermitian positive definite random Toeplitz systems $Ax=b$ by
the preconditioned conjugate gradient method for the Strang circulant
preconditioner is studied. We established the foundation for this method by
extending the work of Brown-Halmos on Toeplitz operators and Grenander-Szeg\"o
on Teoplitz form to random Teoplitz operators.


title: Topological Entropy and Algebraic Entropy for group endomorphisms

abstract:
  The notion of entropy appears in many fields and this paper is a survey about
entropies in several branches of Mathematics. We are mainly concerned with the
topological and the algebraic entropy in the context of continuous
endomorphisms of locally compact groups, paying special attention to the case
of compact and discrete groups respectively. The basic properties of these
entropies, as well as many examples, are recalled. Also new entropy functions
are proposed, as well as generalizations of several known definitions and
results. Furthermore we give some connections with other topics in Mathematics
as Mahler measure and Lehmer Problem from Number Theory, and the growth rate of
groups and Milnor Problem from Geometric Group Theory. Most of the results are
covered by complete proofs or references to appropriate sources.


title:
Mode structure and polaritonic contributions to the Casimir effect in a
  magneto-dielectric cavity

abstract:
  We present a full analysis of the mode spectrum in a cavity formed by two
parallel plates, one of which is a magneto-dielectric, e.g. a metamaterial,
while the other one is metallic, and obtain dispersion relations in closed
form. The optical properties of the cavity walls are described in terms of
realistic models for the effective permittivity and the permeability. Surface
polaritons, i.e. electromagnetic modes that have at least partly an evanescent
character, are shown to dominate the Casimir interaction at small separations.
We analyze in detail the s-polarized polaritons, which are a characteristic
feature of a magneto-dielectric configuration, and discuss their role in the
repulsive Casimir force.


title: Barrier penetration effects in the triple-alpha reaction at low energies

abstract:
  We investigate the triple-alpha reaction at low energies, by assuming a
direct process. The Coulomb potential of three $\alpha$ particles is examined
carefully. The three-body continuum wave functions are generated by calculating
an adiabatic potential barrier. We discuss the influence of the $\alpha\alpha$
potential, and compare our reaction rates with the literature. The reaction
rate at $T=0.01$\,GK is about 10$^3$ times larger than that of NACRE.


title:
Variations of singular spectrum analysis for separability improvement:
  non-orthogonal decompositions of time series

abstract:
  Singular spectrum analysis (SSA) as a nonparametric tool for decomposition of
an observed time series into sum of interpretable components such as trend,
oscillations and noise is considered. The separability of these series
components by SSA means the possibility of such decomposition. Two variations
of SSA, which weaken the separability conditions, are proposed. Both proposed
approaches consider inner products corresponding to oblique coordinate systems
instead of the conventional Euclidean inner product. One of the approaches
performs iterations to obtain separating inner products. The other method
changes contributions of the components by involving the series derivative to
avoid component mixing. Performance of the suggested methods is demonstrated on
simulated and real-life data.


title:
Broad iron lines in neutrons stars: dynamical broadening or wind
  scattering?

abstract:
  Broad iron emission lines are observed in many accreting systems from black
holes in AGN and X-ray binaries to neutron star low-mass X-ray binaries. The
origin of the line broadening is often interpreted as due to dynamical
broadening and relativistic effects. However, alternative interpretations have
been proposed, included broadening due to Compton scattering in a wind or
accretion disk atmosphere. Here we explore the observational signatures
expected from broadening in a wind, in particular that the iron line width
should increase with an increase in the column density of the absorber (due to
an increase in the number of scatterings). We study the data from three neutron
star low-mass X-ray binaries where both a broad iron emission line and
absorption lines are seen simultaneously, and show that there is no significant
correlation between line width and column density. This favors an inner disk
origin for the line broadening rather than scattering in a wind.


title: Strong Traces Model of Self-Assembly Polypeptide Structures

abstract:
  A novel self-assembly strategy for polypeptide nanostructure design was
presented in [Design of a single-chain polypeptide tetrahedron assembled from
coiled-coil segments, Nature Chemical Biology 9 (2013) 362--366]. The first
mathematical model (polypeptide nanostructure can naturally be presented as a
skeleton graph of a polyhedron) from [Stable traces as a model for
self-assembly of polypeptide nanoscale polyhedrons, MATCH Commun. Math. Comput.
Chem. 70 (2013) 317-330] introduced stable traces as the appropriate
mathematical description, yet we find them deficient in modeling graphs with
either very small (less or equal to 2) or large (greater or equal to 6) degree
vertices. We introduce strong traces which remedy both of the above mentioned
drawbacks. We show that every connected graph admits a strong trace by studying
a connection between strong traces and graph embeddings. Further we also
characterize graphs which admit parallel (resp. antiparallel) strong traces.


title: Supersymmetric Custodial Triplets

abstract:
  We analyze the extension of the Minimal Supersymmetric Standard Model which
includes extra Y=(0,\pm 1) supersymmetric triplets with a global SU(2)_L
\otimes SU(2)_R symmetry spontaneousy broken to the custodial SU(2)_V by the
vacuum expectation value of the neutral scalar components of doublets and
triplets. The model is the supersymmetrization of the non-supersymmetric model
introduced long ago by Georgi and Machacek where the \rho-parameter is kept to
unity at the tree-level by the custodial symmetry. Accordingly the scalar
sector is classified into degenerate SU(2)_V multiplets: singlets, triplets
(including the one containing the Godstone bosons) and fiveplets. The singly
and doubly charged chiral superfields play a key role in the unitarization of
the theory. The couplings of the Standard Model-like Higgs to vector bosons
(including \gamma\gamma) and fermions, and the corresponding Higgs signal
strengths, are in agreement with LHC experimental data for a large region of
the parameter space. Breaking of custodial invariance by radiative corrections
suggests a low-scale mechanism of supersymmetry breaking.


title:
Asymptotic behavior of solutions for nonlinear elliptic problems with
  the fractional Laplacian

abstract:
  In this paper we study the asymptotic behavior of least energy solutions and
the existence of multiple bubbling solutions of nonlinear elliptic equations
involving the fractional Laplacians and the critical exponents. This work can
be seen as a nonlocal analog of the results of Han (Ann. Inst. H. Poincare
Anal. Non Lineaire, 1991) and Rey (J. Funct. Anal., 1990).


title:
Combined-Semantics Equivalence Is Decidable for a Practical Class of
  Conjunctive Queries

abstract:
  In this paper, we focus on the problem of determining whether two conjunctive
("CQ") queries posed on relational data are combined-semantics equivalent [9].
We continue the tradition of [2,5,9] of studying this problem using the tool of
containment between queries. We introduce a syntactic necessary and sufficient
condition for equivalence of queries belonging to a large natural language of
"explicit-wave" combined-semantics CQ queries; this language encompasses (but
is not limited to) all set, bag, and bag-set queries, and appears to cover all
combined-semantics CQ queries that are expressible in SQL. Our result solves in
the positive the decidability problem of determining combined-semantics
equivalence for pairs of explicit-wave CQ queries. That is, for an arbitrary
pair of combined-semantics CQ queries, it is decidable (i) to determine whether
each of the queries is explicit wave, and (ii) to determine, in case both
queries are explicit wave, whether or not they are combined-semantics
equivalent, by using our syntactic criterion. (The problem of determining
equivalence for general combined-semantics CQ queries remains open. Even so,
our syntactic sufficient containment condition could still be used to determine
that two general CQ queries are combined-semantics equivalent.) Our equivalence
test, as well as our general sufficient condition for containment of
combined-semantics CQ queries, reduce correctly to the special cases reported
in [2,5] for set, bag, and bag-set semantics. Our containment and equivalence
conditions also properly generalize the results of [9], provided that the
latter are restricted to the language of (combined-semantics) CQ queries.


title:
Beam asymmetry for pi+ and pi0 photoproduction on the proton for photon
  energies from 1.102 to 1.862 GeV

abstract:
  Beam asymmetries for the reactions gamma p -> p pi0 and gamma p -> n pi+ have
been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged,
linearly polarized photon beam with energies from 1.102 to 1.862 GeV. A Fourier
moment technique for extracting beam asymmetries from experimental data is
described. The results reported here possess greater precision and finer energy
resolution than previous measurements. Our data for both pion reactions appear
to favor the SAID and Bonn-Gatchina scattering analyses over the older Mainz
MAID predictions. After incorporating the present set of beam asymmetries into
the world database, exploratory fits made with the SAID analysis indicate that
the largest changes from previous fits are for properties of the Delta(1700)
3/2- and Delta(1905) 5/2+ states.


title: A geometric formulation of uncertainty principle

abstract:
  A geometric approach to formulate the uncertainty principle between quantum
observables acting on an $N$-dimensional Hilbert space is proposed. We consider
the fidelity between a density operator associated with a quantum system and a
projector associated with an observable, and interpret it as the probability of
obtaining the outcome corresponding to that projector. We make use of
fidelity-based metrics such as angle, Bures and root-infidelity ones, to
propose a measure of uncertainty. The triangle inequality allows us to derive a
family of uncertainty relations. In the case of the angle metric, we re-obtain
the Landau--Pollak inequality for pure states and show, in a natural way, how
to extend it to the case of mixed states in arbitrary dimension. In addition,
we derive and compare novel uncertainty relations when using other known
fidelity-based metrics.


title: Base norms and discrimination of generalized quantum channels

abstract:
  We introduce and study norms in the space of hermitian operators, obtained
from base norms in positively generated subspaces. These norms are closely
related to discrimination of so-called generalized quantum channels, including
quantum states, channels and networks. We further introduce generalized quantum
decision problems and show that the maximal average payoff of decision
procedures is again given by these norms. We also study optimality of decision
procedures, in particular, we obtain a necessary and sufficient condition under
which an optimal 1-tester for discrimination of quantum channels exists, such
that the input state is maximally entangled.


title: The entropic pressure of a lattice polygon

abstract:
  The entropic pressure in the vicinity of a two dimensional square lattice
polygon is examined as a model of the entropic pressure near a planar ring
polymer. The scaling of the pressure as a function of distance from the polygon
and length of the polygon is determined and tested numerically.


title: Self-induced white-light seeding laser in a femtosecond laser filament

abstract:
  We report, for what we believe to be the first time, on the generation of
remote self-seeding laser amplification by using only one 800 nm Ti:Sapphire
femtosecond laser pulse. The laser pulse (~ 40 fs) is first used to generate a
filament either in pure nitrogen or in ambient air in which population
inversion between ground and excited states of nitrogen molecular ions is
realized. Self-induced white light inside the filament is then serving as the
seed to be amplified. The self-induced narrow-band laser at 428 nm has a pulse
duration of ~2.6 ps with perfect linear polarization property. This finding
opens new possibilities for remote detection in the atmosphere.


title:
Laser-driven search of axion-like particles including vacuum
  polarization effects

abstract:
  Oscillations of photons into axion-like particles in a high-intensity laser
field are investigated. Nonlinear QED effects are considered through the low
energy behavior of the vacuum polarization tensor, which is derived from the
Euler-Heisenberg Lagrangian in the one-loop and weak field approximations. The
expressions obtained in this framework are applied to the configuration in
which the strong background field is a circularly polarized monochromatic plane
wave. The outcomes of this analysis reveal that, in the regime of low
energy-momentum transfer, the axion field induces a chiral-like birefringence
and dichroism in the vacuum which is not manifest in a pure QED context. The
corresponding ellipticity and angular rotation of the polarization plane are
also determined. We take advantage of such observables to impose exclusion
limits on the axion parameters. Our predictions cover axion masses for which a
setup based on dipole magnets provides less stringent constraints. Possible
experimental scenarios in which our results could be tested are also discussed.


title:
An extension of Ruh-Vilms Theorem for hypersurfaces in symmetric spaces
  and some applications

abstract:
  The main purpose of the paper is twofold: First, to extend a well known
theorem of Ruh-Vilms in the Euclidean space to symmetric spaces and, secondly,
to apply this result to extend Hoffman-Osserman-Schoen Theorem (HOS Theorem) to
3-dimensional symmetric spaces. Precisely, it is defined a Gauss map of a
hypersurface M^{n-1} immersed in a symmetric space N^n taking values in the
unit pseudo sphere S^m of the Lie algebra g of the isometry group of N,
dim(g)=m+1, and it is proved that M has CMC if and only if its Gauss map is
harmonic. As an application, it is proved that if dim(N)=3 and the image of the
Gauss map of a CMC surface S immersed in N is contained in a hemisphere of S^m
determined by a vector X, then S is invariant by the one parameter subgroup of
isometries of N of the Killing field determined by X. In particular, it is
obtained an extension of HOS Theorem to the 3-dimensional hyperbolic space.
  In the paper it is also shown that the holomorphic quadratic form induced by
the Gauss map coincides (up to a sign) with the Hopf quadratic form when the
ambient space is a space form and with the Abresch-Rosenberg quadratic form
when the ambient space is H^2 x R and S^2 x R providing, then, an unified way
of relating Hopf's and Abresch-Rosenberg's quadratic form with the quadratic
form induced by a harmonic Gauss map of a CMC surface in these 5 spaces.


title: Discrete dynamical systems in group theory

abstract:
  In this expository paper we describe an unifying approach for many known
entropies in Mathematics. First we recall the notion of semigroup entropy h_S
in the category S of normed semigroups and contractive homomorphisms, recalling
also its properties. For a specific category X and a functor F from X to S, we
have the entropy h_F, defined by the composition of h_S with F, which
automatically satisfies the same properties proved for h_S. This general scheme
permits to obtain many of the known entropies as h_F, for appropriately chosen
categories X and functors F. In the last part we recall the definition and the
fundamental properties of the algebraic entropy for group endomorphisms, noting
how its deeper properties depend on the specific setting. Finally we discuss
the notion of growth for flows of groups, comparing it with the classical
notion of growth for finitely generated groups.


title:
Fermi surface topology and impurity-induced resonance state in
  BiS$_{2}$-based superconductors

abstract:
  Within the two-orbital model for BiS$_{2}$-based superconductors, the effect
from a single nonmagnetic impurity scattering on the superconducting-state is
investigated in terms of the T-matrix approach. By considering three kinds of
the typical Fermi surface topology which characterize the essential features of
the doping dependence of the electronic structure in BiS$_{2}$-based
superconductors, it is found that the impurity scattering on the
superconducting-state with the conventional $s$-wave, the extended $s$-wave,
the $\pm s$-wave, and the $d_{x^{2}-y^{2}}$-wave symmetries induces
\textit{qualitatively} different resonance states due to the evolution of
unique nodal structures on the Fermi surface with doping. These
impurity-induced resonance states can be verified directly by the scanning
tunneling microscopy experiments, and therefore they are proposed as a probe of
the superconducting pairing symmetry in BiS$_{2}$-based superconductors.


title: The Principle of Stationary Variance in Quantum Field Theory

abstract:
  The principle of stationary variance is advocated as a viable variational
approach to quantum field theory. The method is based on the principle that the
variance of energy should be at its minimum when the state of a quantum system
reaches its best approximation for an eigenstate. While not too much popular in
quantum mechanics, the method is shown to be valuable in quantum field theory,
and three special examples are given in very different areas ranging from
Heisenberg model of antiferromagnetism to quantum electrodynamics and gauge
theories.


title: Multifractal portrayal of the Swiss population

abstract:
  Fractal geometry is a fundamental approach for describing the complex
irregularities of the spatial structure of point patterns. The present research
characterizes the spatial structure of the Swiss population distribution in the
three Swiss geographical regions (Alps, Plateau and Jura) and at the entire
country level. These analyses were carried out using fractal and multifractal
measures for point patterns, which enabled the estimation of the spatial degree
of clustering of a distribution at different scales. The Swiss population
dataset is presented on a grid of points and thus it can be modelled as a
"point process" where each point is characterized by its spatial location
(geometrical support) and a number of inhabitants (measured variable). The
fractal characterization was performed by means of the box-counting dimension
and the multifractal analysis was conducted through the Renyi's generalized
dimensions and the multifractal spectrum. Results showed that the four
population patterns are all multifractals and present different clustering
behaviours. Applying multifractal and fractal methods at different geographical
regions and at different scales allowed us to quantify and describe the
dissimilarities between the four structures and their underlying processes.
This paper is the first Swiss geodemographic study applying multifractal
methods using high resolution data.


title:
Arithmeticity of Four Hypergeometric Monodromy Groups associated to
  Calabi-Yau threefolds

abstract:
  In [12], we show that 3 of the 14 hypergeometric monodromy groups associated
to Calabi-Yau threefolds, are arithmetic. Brav-Thomas (in [3]) show that 7 of
the remaining 11, are thin. In this article, we settle the arithmeticity
problem for the 14 monodromy groups, by showing that, the remaining 4 are
arithmetic.


title:
Integer Solutions, Rational solutions of the equations x^4+y^4+z^4
  -2(x^2)(y^2)-2(y^2)(z^2)-2(z^2)(x^2)=n and
  x^2+y^4+z^4-2x(y^2)-2x(z^2)-2(y^2)(z^2)=n; And Crux Mathematicorum Contest
  problem CC24

abstract:
  The subject matter of this work are the two equations:
x^4+y^4+z^4-2(x^2)(y^2)-2(y^2)(z^2)-2(z^2)(x^2)= n (1) And
x^2+y^4+z^4-2x(y^2)-2x(z^2)-2(y^4)(z^4)= n (2) where n is a natural number.
  Contest Corner problem CC24, published in the May2012 issue of the journal
Crux Mathematicorum(see reference[1]); provided the motivation behind this
work. In Th.1, we show that eq.(1) if n=8N, N odd; then eq.(1) has no integer
solutions; which generalizes problem CC24(the case n=24).
  We use Th.2, to find some rational solutions of eq.(1); which answers the
second question in CC24. In Th.4, we show that if n= p, 4, or pq; where p and q
are distinct primes. Then eq.(1)has no integer solutions. In Th.6, we determine
all the integer solutions to (1), when n=p^2, p an odd prime. Theorems 7
through13, deal with equation (2). In Th.11, we determine all the integer
solutions of eq.(2). Th.12 states that (2) has no integer solutions in n is
congruent to 2 or 3 modulo4. Finally, in Th.13 we determine all the rational
solutions of eq.(2).


title:
A Universal Method for Separating Spin Pumping from Spin Rectification
  Voltage of Ferromagnetic Resonance

abstract:
  We develop a method for universally resolving the important issue of
separating spin pumping (SP) from spin rectification (SR) signals in bilayer
spintronics devices. This method is based on the characteristic distinction of
SP and SR, as revealed in their different angular and field symmetries. It
applies generally for analyzing charge voltages in bilayers induced by the
ferromagnetic resonance (FMR), independent of FMR line shape. Hence, it solves
the outstanding problem that device specific microwave properties restrict the
universal quantification of the spin Hall angle in bilayer devices via FMR
experiments. Furthermore, it paves the way for directly measuring the nonlinear
evolution of spin current generated by spin pumping. The spin Hall angle in a
Py/Pt bilayer is thereby directly measured as 0.021$\pm$0.015 up to a large
precession cone angle of about 20$^{\circ}$.


title:
Importance of Catalyst Stability vis-\`a-vis Hydrogen Peroxide Formation
  Rates in PEM Fuel Cell Electrodes

abstract:
  The role of catalyst stability on the adverse effects of hydrogen peroxide
(H2O2) formation rates in a proton exchange membrane fuel cell (PEMFC) is
investigated for Pt, Pt binary (PtX, X = Co, Ru, Rh, V, Ni) and ternary (PtCoX,
X = Ir, Rh) catalysts. The selectivity of these catalysts towards H2O2
formation in the oxygen reduction reaction (ORR) was measured on a rotating
ring disc electrode. These measured values were used in conjunction with local
oxygen and proton concentrations to estimate local H2O2 formation rates in a
PEMFC anode and cathode. The effect of H2O2 formation rates on the most active
and durable of these catalysts (PtCo and PtIrCo) on Nafion membrane durability
was studied using a single-sided membrane electrode assembly (MEA) with a
built-in reference electrode. Fluoride ion concentration in the effluent water
was used as an indicator of the membrane degradation rate. PtIrCo had the least
fluorine emission rate (FER) followed by PtCo/KB and Pt/KB. Though PtCo and
PtIrCo show higher selectivity for H2O2 formation than unalloyed Pt, they did
not contribute to membrane degradation. This result is explained in terms of
catalyst stability as measured in potential cycling tests in liquid electrolyte
as well as in a functional PEM fuel cell.


title:
Absence of Dynamical Steps in the Exact Correlation Potential in Linear
  Response

abstract:
  Recent work showed that the exact exchange-correlation potential of
time-dependent density functional theory generically displays dynamical step
structures. These have a spatially non-local and time-non-local dependence on
the density in real time dynamics. The steps are missing in the usual
approximations which consequently yield inaccurate dynamics. Yet these same
approximations typically yield good linear response spectra. Here we
investigate whether the steps appear in the linear response regime, when the
response is calculated from a real-time dynamics simulation, by examining the
exact correlation potential of model two-electron systems at various times. We
find there are no step structures in regions where the system response is
linear. Step structures appear in the correlation potential only in regions of
space where the density response is non-linear; these regions, having
exponentially small density, do not contribute to the observables measured in
linear response.


title: Notes on several phenomenological laws of quantum gravity

abstract:
  Phenomenological approaches to quantum gravity try to infer model-independent
laws by analyzing thought experiments and combining both quantum, relativistic,
and gravitational ingredients. We first review these ingredients -three basic
inequalities- and discuss their relationships with the nature of fundamental
constants. In particular, we argue for a covariant mass bound conjecture: in a
spacetime free of horizon, the mass inside a surface $A$ cannot exceed $16 \pi
G^2 m^2< A $, while the reverse holds in a spacetime with horizons. This is
given a precise definition using the formalism of light-sheets. We show that
$\hbar/c$ may be also given a geometrical interpretation, namely $4 \pi
\hbar^2/m^2< A$. We then combine these inequalities and find/review the
following: (1) Any system must have a size greater than the Planck length, in
the sense that there exists a minimal area (2) We comment on the Minimal Length
Scenarios and the fate of Lorentz symmetry near the Planck scale (3) Quanta
with transplanckian frequencies are allowed in a large enough boxes (4) There
exists a mass-dependent maximal acceleration given by $m c^3/\hbar$ if $m<m_p$
and by $c^4/G m$ if $m>m_p$ (5) There exists a mass dependent maximal force and
power (6) There exists a maximal energy density and pressure (7) Physical
systems must obey the Holographic Principle (8) Holographic bounds can only be
saturated by systems with $m>m_p$; systems lying on the ``Compton line'' $l
\sim 1/m$ are fundamental objects without substructures (9) We speculate on a
new bound from above for the action. In passing, we note that the maximal
acceleration is of the order of Milgrom's acceleration $a_0$ for ultra-light
particles ($m\sim H_0)$ that could be associated to the Dark Energy fluid. This
suggests designing toy-models in which modified gravity in galaxies is driven
by the DE field, via the maximal acceleration principle.


title: Efficient Leverage of Symbolic ATG Tools to Advanced Coverage Criteria

abstract:
  Automatic test data generation (ATG) is a major topic in software
engineering. In this paper, we seek to bridge the gap between the coverage
criteria supported by symbolic ATG tools and the most advanced coverage
criteria found in the literature. We define a new testing criterion, label
coverage, and prove it to be both expressive and amenable to efficient
automation. We propose several innovative techniques resulting in an effective
black-box support for label coverage, while a direct approach induces an
exponential blow-up of the search space. Initial experiments show that ATG for
label coverage can be achieved at a reasonable cost and that our optimisations
yield very significant savings.


title:
Direct Numerical Simulations of Reflection-Driven, Reduced MHD
  Turbulence from the Sun to the Alfven Critical Point

abstract:
  We present direct numerical simulations of inhomogeneous reduced
magnetohydrodynamic (RMHD) turbulence between the Sun and the Alfv\'en critical
point. These are the first such simulations that take into account the
solar-wind outflow velocity and the radial inhomogeneity of the background
solar wind without approximating the nonlinear terms in the governing
equations. RMHD turbulence is driven by outward-propagating Alfv\'en waves
($z^+$ fluctuations) launched from the Sun, which undergo partial non-WKB
reflection to produce sunward-propagating Alfv\'en waves ($z^-$ fluctuations).
We present ten simulations with different values of the correlation time
$\tau_{\rm c\,\sun}^+$ and perpendicular correlation length $L_{\perp \sun}$ of
outward-propagating Alfv\'en waves (AWs) at the coronal base. We find that
between 15% and 33% of the $z^+$ energy launched into the corona dissipates
between the coronal base and Alfv\'en critical point. Between 33% and 40% of
this input energy goes into work on the solar-wind outflow, and between 22% and
36% escapes as $z^+$ fluctuations through the simulation boundary at $r=r_{\rm
A}$. The $z^\pm$ power spectra scale like $k_\perp^{-\alpha^\pm}$, where
$k_\perp$ is the wavenumber in the plane perpendicular to $\vec{B}_0$. In our
simulation with the smallest value of $\tau_{\rm c\,\sun}^+$ ($\sim 2
\mbox{min}$) and largest value of $L_{\perp \sun}$ ($2\times 10^4 \mbox{km}$),
we find that $\alpha^+$ decreases approximately linearly with increasing
$\ln(r)$, reaching a value of 1.3 at $r=11.1 R_{\sun}$. Our simulations with
larger values of $\tau_{\rm c\,\sun}^+$ exhibit alignment between the contours
of constant $\phi^+$, $\phi^-$, $\Omega_0^+$, and $\Omega_0^-$, where
$\phi^\pm$ are the Els\"asser potentials and $\Omega_0^\pm$ are the outer-scale
parallel Els\"asser vorticities.


title: Automorphisms of Manifolds and Algebraic K-Theory: Part III

abstract:
  The structure space S(M) of a closed topological m-manifold M classifies
bundles whose fibers are closed m-manifolds equipped with a homotopy
equivalence to M. We construct a highly connected map from S(M) to a concoction
of algebraic L-theory and algebraic K-theory spaces associated with M. The
construction refines the well-known surgery theoretic analysis of the block
structure space of M in terms of L-theory.


title: Gcube Indexing

abstract:
  Spatial Online Analytical Processing System involves the non-categorical
attribute information also whereas standard Online Analytical Processing System
deals with only categorical attributes. Providing spatial information to the
data warehouse (DW); two major challenges faced are;1.Defining and Aggregation
of Spatial/Continues values and 2.Representation, indexing, updating and
efficient query processing. In this paper, we present GCUBE(Geographical Cube)
storage and indexing procedure to aggregate the spatial information/Continuous
values. We employed the proposed approach storing and indexing using synthetic
and real data sets and evaluated its build, update and Query time. It is
observed that the proposed procedure offers significant performance advantage.


title: Payoff Performance of Fictitious Play

abstract:
  We investigate how well continuous-time fictitious play in two-player games
performs in terms of average payoff, particularly compared to Nash equilibrium
payoff. We show that in many games, fictitious play outperforms Nash
equilibrium on average or even at all times, and moreover that any game is
linearly equivalent to one in which this is the case. Conversely, we provide
conditions under which Nash equilibrium payoff dominates fictitious play
payoff. A key step in our analysis is to show that fictitious play dynamics
asymptotically converges the set of coarse correlated equilibria (a fact which
is implicit in the literature).


title: A Direct Measurement of the Total Decay Width of the Top Quark

abstract:
  We present a measurement of the total decay width of the top quark using
events with top-antitop-quark pair candidates reconstructed in the final state
with one charged lepton and four or more hadronic jets. We use the full
Tevatron Run II data set of $\sqrt{s} = 1.96$ TeV proton-antiproton collisions
recorded by the CDF II detector. The top-quark mass and the mass of the
hadronically-decaying $W$ boson are reconstructed for each event and compared
with distributions derived from simulated signal and background samples to
extract the top-quark width (\gmt) and the energy scale of the calorimeter jets
with {\it in-situ} calibration. For a top-quark mass $\mtop = \gevcc{172.5}$,
we find $1.10<\gmt<\gev{4.05}$ at 68% confidence level, which is in agreement
with the standard-model expectation of \gev{1.3} and is the most precise direct
measurement of the top-quark width to date.


title: A Kolmogorov-Like Exact Relation for Compressible Polytropic Turbulence

abstract:
  Compressible hydrodynamic turbulence is studied under the assumption of a
polytropic closure. Following Kolmogorov, we derive an exact relation for some
two-point correlation functions in the asymptotic limit of a high Reynolds
number.


title: Fano Interference between a STM Tip and Mid Gap States in Graphene

abstract:
  We analyze the STM current through electronic resonances on a substrate as a
function of tip-surface distance. We show that when the tip approaches the
surface a Fano hybridization can occur between the electronic resonance on the
substrate and the continuum of conduction states in the STM tip. A maximum of
the density of states of the electronic resonance at some energy can then lead
to a dip of the STM signal $dI/dV$. Resonances in graphene, known as mid gap
states, are good candidates to produce this type of Fano interference. The mid
gap states can be produced by local defects or adsorbates and we analyze the
cases of top and hollow configurations of adsorbates.


title:
Stability of Z$_2$ topological order in the presence of vacancy-induced
  impurity band

abstract:
  Although topological insulators (TIs) are known to be robust against
non-magnetic perturbations and exhibit edge or surface states as their distinct
feature, experimentally it is known that vacancies often occur in these
materials and impose strong perturbations. Here we investigate effects of
vacancies on the stability of Z$_{2}$ topological order using the Kane-Mele
(KM) model as a prototype of topological insulator. It is shown that even
though a vacancy is not classified as a topological defect in KM model, it
generally induces a pair of degenerate midgap states only in the TI phase. We
show that these midgap states results from edge states that fit into vacancies
and are characterized by the same Z$_{2}$ topological order. Furthermore, in
the presence of many vacancies, an impurity band that is degenerate with edge
states in energy is induced and mixes directly with edge states. However, the
Z$_{2}$ topological order persists and edge states exist between the impurity
band and perturbed bulk bands until a phase transition occurs when Dirac cones
near Dirac points are depleted. Our analyses indicate that the same scenario
holds for point vacancies or line of vacancies in 3D TIs as well.


title:
Calculations of the cross sections for synthesis of new {293-296}118
  isotopes in {249-252}Cf(48Ca,xn) reactions

abstract:
  A project of using a target consisting of the mixture of (249-252)Cf isotopes
to be bombarded with the 48Ca beam, aimed to synthesize new isotopes of the
heaviest known element Z = 118, is under way at the FLNR in Dubna. In the
present work excitation functions for all the reactions:
249Cf(48Ca,xn)(297-x)118, 250Cf(48Ca,xn)(298-x)118, 251Cf(48Ca,xn)(299-x)118
and 252Cf(48Ca,xn)(300-x)118 have been calculated in the framework of the
fusion-by-diffusion model, assuming fission barriers, ground-state masses and
shell effects of the superheavy nuclei predicted by Kowal et al. Energy
dependence of the effective cross sections for the synthesis of selected new
isotopes: (293)118, (294)118, (295)118 and (296)118 is predicted for the
particular isotopic composition of the Cf target prepared for the Dubna
experiment.


title: Why decoherence solves the measurement problem

abstract:
  Although the solution, within standard quantum physics, of the problem of
outcomes has been published several times, many authors continue to treat
measurement as an unsolved fundamental dilemma. The solution lies in the
formation of entangled subsystems, the non-local nature of the measurement
state, and the resulting distinction between mixed-state local outcomes and the
pure-state global outcome. Upon "measurement" (i.e. entanglement), the quantum
system and its measurement apparatus both decohere and collapse into local
mixed states while the unitarily-evolving global state remains coherent and
un-collapsed. The states we observe are the local, collapsed states.
Considerable experimental evidence supports this conclusion. Theoretical
objections to this conclusion are rebutted, and a new perspective on
measurement and entanglement is noted.


title: On counting orbits in root systems

abstract:
  The computation of the characters of supercuspidal representations of a
p-adic group involves some 4th roots of unity whose values are defined in terms
of orbits of the Galois group of a p-field on a root system. The part of the
definition that is of interest in the verification of stability of character
sums involves just the parity of the number of Galois orbits. In this paper, we
re-cast the definition (nearly) in terms only of the abstract action of a pair
of automorphisms on a root system, and compute it by a series of reductions in
all cases.


title: Geometric phase and phase diagram for non-Hermitian quantum XY model

abstract:
  We study the geometric phase for the ground state of a generalized
one-dimensional non-Hermitian quantum XY model, which has
transverse-field-dependent intrinsic rotation-time reversal symmetry. Based on
the exact solution, this model is shown to have full real spectrum in multiple
regions for the finite size system. The result indicates that the phase diagram
or exceptional boundary, which separates the unbroken and broken symmetry
regions corresponds to the divergence of the Berry curvature. The scaling
behaviors of the groundstate energy and Berry curvature are obtained in an
analytical manner for a concrete system.


title: Quantum Hall Effects in Monolayer-Bilayer Graphene Planar Junctions

abstract:
  The Hall resistance of a homogeneous electron system is well known to be
anti-symmetric with respect to the magnetic field and the sign of charge
carriers. We have observed that such symmetries no longer hold in planar hybrid
structures consisting of partly single layer graphene (SLG) and partly bilayer
graphene (BLG) in the quantum Hall (QH) regime. In particular, the Hall
resistance (R12xy) across the SLG and BLG interface is observed to exhibit
quantized plateaus that switch between those characteristic of SLG QH states
and BLG QH states when either the sign of the charge carriers (controlled by a
back gate) or the direction of the magnetic field is reversed. Simultaneously
reversing both the carrier type and the magnetic field gives rise to the same
quantized Hall resistances. The observed SLG-BLG interface QH states, with
characteristic asymmetries with respect to the signs of carriers and magnetic
field, are determined only by the chirality of the QH edge states and can be
explained by a Landauer-B\"uttiker analysis applied to such graphene hybrid
structures involving two regions of different Landau level (LL) structures.


title:
Interference Effects in Bethe-Heitler Pair Creation in a Bichromatic
  Laser Field

abstract:
  We study the creation of electron-positron pairs in the superposition of a
nuclear Coulomb field and a two-color laser field of high intensity. Our focus
lies on quantum interference effects, which may arise if the two laser
frequencies are commensurable. We show that the interference manifests in the
angular distributions of the created particles, which are discussed in the
nuclear rest frame and the laboratory frame. Additionally, we demonstrate that
the total pair-production rates can be affected by interference and identify
the relative phase between the two laser modes, which optimizes the
pair-production yield.


title: Polyadic systems, representations and quantum groups

abstract:
  Polyadic systems and their representations are reviewed and a classification
of general polyadic systems is presented. A new multiplace generalization of
associativity preserving homomorphisms, a 'heteromorphism' which connects
polyadic systems having unequal arities, is introduced via an explicit formula,
together with related definitions for multiplace representations and
multiactions. Concrete examples of matrix representations for some ternary
groups are then reviewed. Ternary algebras and Hopf algebras are defined, and
their properties are studied. At the end some ternary generalizations of
quantum groups and the Yang-Baxter equation are presented.

categories: math.RT hep-th math-ph math.GR math.MP math.QA


title: Quantum Quench and Double Trace Couplings

abstract:
  We consider quantum quench by a time dependent double trace coupling in a
strongly coupled large N field theory which has a gravity dual via the AdS/CFT
correspondence. The bulk theory contains a self coupled neutral scalar field
coupled to gravity with negative cosmological constant. We study the scalar
dynamics in the probe approximation in two backgrounds: AdS soliton and AdS
black brane. In either case we find that in equilibrium there is a critical
phase transition at a {\em negative} value of the double trace coupling
$\kappa$ below which the scalar condenses. For a slowly varying homogeneous
time dependent coupling crossing the critical point, we show that the dynamics
in the critical region is dominated by a single mode of the bulk field. This
mode satisfies a Landau-Ginsburg equation with a time dependent mass, and leads
to Kibble Zurek type scaling behavior. For the AdS soliton the system is
non-dissipative and has $z=1$, while for the black brane one has dissipative
$z=2$ dynamics. We also discuss the features of a holographic model which would
describe the non-equilibrium dynamics around quantum critical points with
arbitrary dynamical critical exponent $z$ and correlation length exponent
$\nu$. These analytical results are supported by direct numerical solutions.


title:
$L^{p}$ estimates for multi-linear and multi-parameter
  pseudo-differential operators

abstract:
  We establish the pseudo-differential variant of the $L^{p}$ estimates for
multi-linear and multi-parameter Coifman-Meyer multiplier operators proved by
C. Muscalu, J. Pipher, T. Tao and C. Thiele in \cite{MPTT1,MPTT2}.


title:
Covariant Loop Quantum Gravity, Low Energy Perturbation Theory, and
  Einstein Gravity with High Curvature UV Corrections

abstract:
  A low-energy perturbation theory is developed from the nonperturbative
framework of covariant Loop Quantum Gravity (LQG) by employing the background
field method. The resulting perturbation theory is a 2-parameter expansion in
the semiclassical and low-energy regime. The two expansion parameters are the
large spin and small curvature. The leading order effective action coincides
with the Einstein-Hilbert action. The subleading corrections organized by the
two expansion parameters give the modifications of Einstein gravity in quantum
and high-energy regime from LQG. The perturbation theory developed here shows
for the first time that covariant LQG produces the high curvature corrections
to Einstein gravity. This result means that LQG is not a naive quantization of
Einstein gravity, but rather provides the UV modification. The result of the
paper may be viewed as the first step toward understanding the UV completeness
of LQG.


title:
An Integer Programming Approach to the Hospital/Residents Problem with
  Ties

abstract:
  The classical Hospitals/Residents problem (HR) models the assignment of
junior doctors to hospitals based on their preferences over one another. In an
instance of this problem, a stable matching M is sought which ensures that no
blocking pair can exist in which a resident r and hospital h can improve
relative to M by becoming assigned to each other. Such a situation is
undesirable as it could naturally lead to r and h forming a private arrangement
outside of the matching. The original HR model assumes that preference lists
are strictly ordered. However in practice, this may be an unreasonable
assumption: an agent may find two or more agents equally acceptable, giving
rise to ties in its preference list. We thus obtain the Hospitals/Residents
problem with Ties (HRT). In such an instance, stable matchings may have
different sizes and MAX HRT, the problem of finding a maximum cardinality
stable matching, is NP-hard. In this paper we describe an Integer Programming
(IP) model for MAX HRT. We also provide some details on the implementation of
the model. Finally we present results obtained from an empirical evaluation of
the IP model based on real-world and randomly generated problem instances.


title: Graphene-based Bolometers

abstract:
  This article reviews recent research for development of sensitive graphene
photon detectors in the infrared/far infrared/THz range. For this range,
graphene has promising potential in thermal photon detectors. Graphene has
ultra-small volume and low electron density, which gives relatively large
heating per absorbed photon and fast response. At low temperatures the
electron-phonon energy loss is small, so ultrasensitive power detection is
possible. We review recent research on the science base of such detectors, and
outline the major design challenges. Important factors that must be considered
in making useful detectors include the photon and readout coupling efficiency,
the method of electron temperature readout, and thermal isolation of the hot
electrons.


title: Supermetallic and Trapped States in Periodically Kicked Lattices

abstract:
  A periodically driven lattice with two commensurate spatial periodicities is
found to exhibit super metallic states characterized by enhancements in wave
packet spreading and entropy. These resonances occur at critical values of
parameters where multi-band dispersion curves reduce to a universal function
that is topologically a circle and the effective quantum dynamics describes
free propagation. Sandwiching every resonant state are a pair of anti-resonant
{\it trapped states} distinguished by dips in entropy where the transport, as
seen in the spreading rate, is only somewhat inhibited. Existing in gapless
phases fo the spectrum, a sequence of these peaks and dips are interspersed by
gapped phases assocated with flat band states where both the wave packet
spreading as well as the entropy exhibit local minima.


title:
The S-metric, the Beichl-Cloteaux approximation, and preferential
  attachment

abstract:
  The S-metric has grown popular in network studies, as a measure of
``scale-freeness'' restricted to the collection G(D) of connected graphs with a
common degree sequence D=(d_1,\ldots,d_n). The calculation of S depends on the
maximum possible degree assortativity r among graphs in G(D). The original
method involves a heuristic construction of a maximally assortative graph g*.
The approximation by Beichl and Cloteaux involves constructing a possibly
disconnected graph g' with r(g') >= r(g*) and requires O(n^2) tests for the
graphicality of a degree sequence. The present paper uses the Tripathi-Vijay
test to streamline this approximation, and thereby to investigate two
collections of graphs: Barabasi-Albert trees and coauthorship graphs of
mathematical sciences researchers. Long-term trends in the coauthorship graphs
are discussed, and contextualized by insights derived from the BA trees. It is
known that greater degree-based preferential attachment produces greater
variance in degree sequences, and these trees exhibited assortativities
restricted to a narrow band. In contrast, variance in degree rose over time in
the coauthorship graphs in spite of weakening degree-based preferential
attachment. These observations and their implications are discussed and avenues
of future work are suggested.


title:
The Herschel PACS photometer calibration - A time dependent flux
  calibration for the PACS chopped point-source photometry AOT mode

abstract:
  We present a flux calibration scheme for the PACS chopped point-source
photometry observing mode based on the photometry of five stellar standard
sources. This mode was used for science observations only early in the mission.
Later, it was only used for pointing and flux calibration measurements. Its
calibration turns this type of observation into fully validated data products
in the Herschel Science Archive. Systematic differences in calibration with
regard to the principal photometer observation mode, the scan map, are derived
and amount to 5-6%. An empirical method to calibrate out an apparent response
drift during the first 300 Operational Days is presented. The relative
photometric calibration accuracy (repeatability) is as good as 1% in the blue
and green band and up to 5% in the red band. Like for the scan map mode,
inconsistencies among the stellar calibration models become visible and amount
to 2% for the five standard stars used. The absolute calibration accuracy is
therefore mainly limited by the model uncertainty, which is 5% for all three
bands.