title: Phase shifts in I=2 {\pi}{\pi}-scattering from two lattice approaches

abstract:
  We present a lattice QCD study of the phase shift of $I{=}2$ $\pi\pi$
scattering on the basis of two different approaches: the standard finite volume
approach by Luscher and the recently introduced HAL QCD potential method.
Quenched QCD simulations are performed on lattices with extents
$N_s{=}16,24,32,48$ and $N_t{=}128$ as well as lattice spacing
$a{\sim}0.115\,\mathrm{fm}$ and a pion mass of $m_\pi{\sim}940\,\mathrm{MeV}$.
The phase shift and the scattering length are calculated in these two methods.
In the potential method, the error is dominated by the systematic uncertainty
associated with the violation of rotational symmetry due to finite lattice
spacing. In Luscher's approach, such systematic uncertainty is difficult to be
evaluated and thus is not included in this work. A systematic uncertainty
attributed to the quenched approximation, however, is not evaluated in both
methods. In case of the potential method, the phase shift can be calculated for
arbitrary energies below the inelastic threshold. The energy dependence of the
phase shift is also obtained from Luscher's method using different volumes
and/or nonrest-frame extension of it. The results are found to agree well with
the potential method.


title: Fundamental diagrams for kinetic equations of traffic flow

abstract:
  In this paper we investigate the ability of some recently introduced discrete
kinetic models of vehicular traffic to catch, in their large time behavior,
typical features of theoretical fundamental diagrams. Specifically, we address
the so-called "spatially homogeneous problem" and, in the representative case
of an exploratory model, we study the qualitative properties of its solutions
for a generic number of discrete microstates. This includes, in particular,
asymptotic trends and equilibria, whence fundamental diagrams originate.


title: Gravitational waves from a curvaton model with blue spectrum

abstract:
  We investigate the gravitational wave background induced by the first order
scalar perturbations in the curvaton models. We consider the quadratic and
axion-like curvaton potential which can generate the blue-tilted power spectrum
of curvature perturbations on small scales and derive the maximal amount of
gravitational wave background today. We find the power spectrum of the induced
gravitational wave background has a characteristic peak at the frequency
corresponding to the scale reentering the horizon at the curvaton decay, in the
case where the curvaton does not dominate the energy density of the Universe.
We also find the enhancement of the amount of the gravitational waves in the
case where the curvaton dominates the energy density of the Universe. Such
induced gravitational waves would be detectable by the future space-based
gravitational wave detectors or pulsar timing observations.


title:
Scaling relations of the slightly self-interacting cold dark matter in
  galaxies and clusters

abstract:
  Recent observations in galaxies and clusters indicate dark matter density
profiles exhibit core-like structures which contradict to the numerical
simulation results of collisionless cold dark matter. The idea of
self-interacting cold dark matter (SICDM) has been invoked to solve the
discrepancies between the observations and numerical simulations. In this
article, I derive some important scaling relations in galaxies and clusters by
using the long-range SICDM model. These scaling relations give good agreements
with the empirical fittings from observational data in galaxies and clusters if
the dark matter particles are only slightly self-interacting. Also, there may
exist a universal critical optical depth $\tau_c$ that characterizes the
core-like structures. These results generally support the idea of SICDM to
tackle the long-lasting dark matter problem.


title:
Fluctuations and the role of collision duration in reaction-diffusion
  systems

abstract:
  In a reaction-diffusion system, fluctuations in both diffusion and reaction
events, have important effects on the steady-state statistics of the system.
Here, we argue through extensive lattice simulations, mean-field type
arguments, and the Doi-Peliti formalism that the collision duration statistics
-- i.e., the time two particles stay together in a lattice site -- plays a
leading role in determining the steady state of the system. We obtain
approximate expressions for the average densities of the chemical species and
for the critical diffusion coefficient required to sustain the reaction.


title: Energy uncertainty of the final state of a decay process

abstract:
  We derive the expression for the energy uncertainty of the final state of a
decay of an unstable quantum state prepared at the initial time $t=0$. This
expression is function of the time $t$ at which a measurement is performed to
determine if the state has decayed and, if yes, in which one of the infinitely
many possible final states. For large times the energy spread is, as expected,
given by the decay width $\Gamma$ of the initial unstable state. However, if
the measurement of the final state is performed at a time $t$ comparable to (or
smaller than) the mean lifetime of the state $1/\Gamma$, then the uncertainty
on the energy of the final state is much larger than the decay width $\Gamma$.
Namely, for short times an uncertainty of the type $1/t$ dominates, while at
large times the usual spread $\Gamma$ is recovered. Then, we turn to a generic
two-body decay process and describe the energy uncertainty of each one of the
two outgoing particles. We apply these formulas to the two-body decays of the
neutral and charged pions and to the spontaneous emission process of an excited
atom. As a last step, we study a case in which the non-exponential decay is
realized ad show that for short times eventual asymmetric terms are enhanced in
the spectrum.


title:
Team and Person-by-Person Optimality Conditions of Differential Decision
  Systems

abstract:
  In this paper, we derive team and person-by-person optimality conditions for
distributed differential decision systems with different or decentralized
information structures. The necessary conditions of optimality are given in
terms of Hamiltonian system of equations consisting of a coupled backward and
forward differential equations and a Hamiltonian projected onto the subspace
generated by the decentralized information structures. Under certain global
convexity conditions it is shown that the optimality conitions are also
sufficient.


title: A challenge for critical point of spin glass in ground state

abstract:
  We show several calculations to identify the critical point in the ground
state in random spin systems including spin glasses on the basis of the duality
analysis. The duality analysis is a profound method to obtain the precise
location of the critical point in finite temperature even for spin glasses. We
propose a single equality for identifying the critical point in the ground
state from several speculations. The equality can indeed give the exact
location of the critical points for the bond-dilution Ising model on several
lattices and provides insight on further analysis on the ground state in spin
glasses.


title: On emergent SUSY gauge theories

abstract:
  We present the basic features of emergent SUSY gauge theories where an
emergence of gauge bosons as massless vector Nambu-Goldstone modes is triggered
by the spontaneously broken supersymmetry rather than the physically manifested
Lorentz violation. We start considering the supersymmetric QED model extended
by an arbitrary polynomial potential of massive vector superfield that induces
the spontaneous SUSY violation in the visible sector. As a consequence, a
massless photon appears as a companion of a massless photino emerging as a
goldstino in the tree approximation, and remains massless due to the
simultaneously generated special gauge invariance. This invariance is only
restricted by the supplemented vector field constraint invariant under
supergauge transformations. Meanwhile, photino being mixed with another
goldstino appearing from a spontaneous SUSY violation in the hidden sector
largely turns into the light pseudo-goldstino. Such pseudo-goldstonic photinos
considered in an extended supersymmetric Standard Model framework are of a
special observational interest that, apart from some indication of the QED
emergence nature, may appreciably extend the scope of SUSY breaking physics
being actively studied in recent years.


title:
Annular cracks in thin films of nanoparticle suspensions drying on a
  fiber

abstract:
  We report an experimental study of the crack pattern formed during the drying
of a colloidal suspension. A horizontal fiber, which provides a one
dimensional, boundary-free substrate, is coated by a film of micronic
thickness. The geometry imposes a remarkable annular crack pattern and allowing
precise measurements of the crack spacing over a short range of film thickness
(between 2 and 10 $\mu$m) which varies linearly with the film height. We
compare our experimental data with a model proposed by Kitsunezaki which
suggests that the variation of the crack spacing with the film thickness
depends on the ratio between a critical stress at cracking and a critical
stress for slipping on the substrate. By measuring the friction force of the
colloidal gels on a hydrophobic surface through a cantilever technique, we can
deduce the critical crack stress for these colloidal gels simply by measuring
the crack spacing of the pattern.


title: Test of Genuine Multipartite Nonlocality Without Inequality

abstract:
  In this letter we propose a set of conditions on the joint probabilities as a
test of genuine multipartite nonlocality without inequality. Our test is failed
by all non-signaling local models in which even nonlocal correlations among
some observables (not all) are allowed as long as these correlations respect
the non-signaling principle. A pass of our test by a state therefore indicates
that this state cannot be simulated by any non-signaling local models, i.e.,
the state exhibits genuine multipartite nonlocality. It turns out that all
entangled symmetric n-qubit ($n \geq 3$) states pass our test and therefore are
n-way nonlocal. Also we construct two Bell-type inequalities from our proposed
test whose violations indicate genuine multipartite nonlocal correlations.


title:
Spontaneous Symmetry Breaking in Quantum Systems: Emergence or
  Reduction?

abstract:
  Beginning with Anderson (1972), spontaneous symmetry breaking (SSB) in
infinite quantum systems is often put forward as an example of (asymptotic)
emergence in physics, since in theory no finite system should display it. Even
the correspondence between theory and reality is at stake here, since numerous
real materials show SSB in their ground states (or equilibrium states at low
temperature), although they are finite. Thus against what is sometimes called
`Earman's Principle', a genuine physical effect (viz. SSB) seems theoretically
recovered only in some idealization (namely the thermodynamic limit),
disappearing as soon as the the idealization is removed. We review the
well-known arguments that (at first sight) no finite system can exhibit SSB,
using the formalism of algebraic quantum theory in order to control the
thermodynamic limit and unify the description of finite- and infinite-volume
systems. Using the striking mathematical analogy between the thermodynamic
limit and the classical limit, we show that a similar situation obtains in
quantum mechanics (which typically forbids SSB) versus classical mechanics
(which allows it). This discrepancy between formalism and reality is quite
similar to the measurement problem, and hence we address it in the same way,
adapting an argument of the author and Reuvers (2013) that was originally
intended to explain the collapse of the wave-function within conventional
quantum mechanics. Namely, exponential sensitivity to (asymmetric)
perturbations of the (symmetric) dynamics as the system size increases causes
symmetry breaking already in finite but very large quantum systems. This
provides continuity between finite- and infinite-volume descriptions of quantum
systems featuring SSB and hence restores Earman's Principle (at least in this
particularly threatening case).


title: On certain submodules of Weyl modules for SO(2n+1,F) with char(F) = 2

abstract:
  For $k = 1, 2,...,n-1$ let $V_k = V(\lambda_k)$ be the Weyl module for the
special orthogonal group $G = \mathrm{SO}(2n+1,\F)$ with respect to the $k$-th
fundamental dominant weight $\lambda_k$ of the root system of type $B_n$ and
put $V_n = V(2\lambda_n)$. It is well known that all of these modules are
irreducible when $\mathrm{char}(\F) \neq 2$ while when $\mathrm{char}(\F) = 2$
they admit many proper submodules. In this paper, assuming that
$\mathrm{char}(\F) = 2$, we prove that $V_k$ admits a chain of submodules $V_k
= M_k \supset M_{k-1}\supset ... \supset M_1\supset M_0 \supset M_{-1} = 0$
where $M_i \cong V_i$ for $1,..., k-1$ and $M_0$ is the trivial 1-dimensional
module. We also show that for $i = 1, 2,..., k$ the quotient $M_i/M_{i-2}$ is
isomorphic to the so called $i$-th Grassmann module for $G$. Resting on this
fact we can give a geometric description of $M_{i-1}/M_{i-2}$ as a submodule of
the $i$-th Grassmann module. When $\F$ is perfect $G\cong \mathrm{Sp}(2n,\F)$
and $M_i/M_{i-1}$ is isomorphic to the Weyl module for $\mathrm{Sp}(2n,\F)$
relative to the $i$-th fundamental dominant weight of the root system of type
$C_n$. All irreducible sections of the latter modules are known. Thus, when
$\F$ is perfect, all irreducible sections of $V_k$ are known as well.


title:
Experimental estimation of quantum discord for polarization qubit and
  the use of fidelity to assess quantum correlations

abstract:
  We address the experimental determination of entropic quantum discord for
systems made of a pair of polarization qubits. We compare results from full and
partial tomography and found that the two determinations are statistically
compatible, with partial tomography leading to a smaller value of discord for
depolarized states. Despite the fact that our states are well described, in
terms of fidelity, by families of depolarized or phase-damped states, their
entropic discord may be largely different from that predicted for these classes
of states, such that no reliable estimation procedure beyond tomography may be
effectively implemented. Our results, together with the lack of an analytic
formula for the entropic discord of a generic two-qubit state, demonstrate that
the estimation of quantum discord is an intrinsically noisy procedure. Besides,
we question the use of fidelity as a figure of merit to assess quantum
correlations.


title: Beam energy dependence of strange hadron production from STAR at RHIC

abstract:
  We present STAR measurements of K^{0}_{S}, \phi, \Lambda, \Xi, and \Omega at
mid-rapidity from Au+Au collisions at \sqrt{s_{NN}} = 7.7, 11.5, 19.6, 27, and
39 GeV from the Beam Energy Scan (BES) program at the BNL Relativistic Heavy
Ion Collider (RHIC). Nuclear modification factors and baryon-to-meson ratios
are measured to understand recombination and parton energy loss mechanisms.
Implications on partonic versus hadronic dynamics at low beam energies are
discussed.


title:
Energy- and enstrophy-conserving schemes for the shallow-water
  equations, based on mimetic finite elements

abstract:
  This paper presents a family of spatial discretisations of the nonlinear
rotating shallow-water equations that conserve both energy and potential
enstrophy. These are based on two-dimensional mixed finite element methods and
hence, unlike some finite difference methods, do not require an orthogonal
grid. Numerical verification of the aforementioned properties is also provided.


title: Properties of modified Riemannian extensions

abstract:
  Let $M$ be an $n-$dimensional differentiable manifold with a symmetric
connection $\nabla $ and $T^{\ast}M$ be its cotangent bundle. In this paper, we
study some properties of the modified Riemannian extension $%
\widetilde{g}_{\nabla,c}$ on $T^{\ast}M$ defined by means of a symmetric $%
(0,2)$-tensor field $c$ on $M.$ We get the conditions under which $T^{\ast}M $
endowed with the horizontal lift $^{H}J$ of an almost complex structure $J$ and
with the metric $\widetilde{g}_{\nabla,c}$ is a K\"{a}hler-Norden manifold.
Also curvature properties of the Levi-Civita connection and another metric
connection of the metric $\widetilde{g}_{\nabla,c}$ are presented.


title:
Nonequilibrium density matrix for quantum transport: Hershfield approach
  as a McLennan-Zubarev form of the statistical operator

abstract:
  In this paper, we formally demonstrate that the non-equilibrium density
matrix developed by Hershfield for the steady state has the form of a
McLennan-Zubarev non-equilibrium ensemble. The correction term in this pseudo
equilibrium Gibbs-like ensemble is directly related to the entropy production
in the quantum open system. The fact the both methods state that a
non-equilibrium steady state can be mapped onto a pseudo-equilibrium, permits
us to develop non-equilibrium quantities from formal expressions equivalent to
the equilibrium case. We provide an example: the derivation of a
non-equilibrium distribution function for the electron population in a
scattering region in the context of quantum transport.


title: Summary of the 2013 IACHEC Meeting

abstract:
  We present the main results of the 8th International Astronomical Consortium
for High Energy Calibration (IACHEC) meeting, held in Theddingworth,
Leicestershire, between March 25 and 28, 2013. Over 50 scientists directly
involved in the calibration of operational and future high-energy missions
gathered during 3.5 days to discuss the status of the X-ray payload
inter-calibration, as well as possible ways to improve it. Sect. 4 of this
Report summarises our current understanding of the energy-dependent
inter-calibration status.


title: A single-atom electron spin qubit in silicon

abstract:
  A single atom is the prototypical quantum system, and a natural candidate for
a quantum bit - the elementary unit of a quantum computer. Atoms have been
successfully used to store and process quantum information in electromagnetic
traps, as well as in diamond through the use of the NV-center point defect.
Solid state electrical devices possess great potential to scale up such
demonstrations from few-qubit control to larger scale quantum processors. In
this direction, coherent control of spin qubits has been achieved in
lithographically-defined double quantum dots in both GaAs and Si. However, it
is a formidable challenge to combine the electrical measurement capabilities of
engineered nanostructures with the benefits inherent to atomic spin qubits.
Here we demonstrate the coherent manipulation of an individual electron spin
qubit bound to a phosphorus donor atom in natural silicon, measured
electrically via single-shot readout. We use electron spin resonance to drive
Rabi oscillations, while a Hahn echo pulse sequence reveals a spin coherence
time (T2) exceeding 200 \mu s. This figure is expected to become even longer in
isotopically enriched 28Si samples. Together with the use of a device
architecture that is compatible with modern integrated circuit technology,
these results indicate that the electron spin of a single phosphorus atom in
silicon is an excellent platform on which to build a scalable quantum computer.


title:
A Bernstein-von Mises theorem for smooth functionals in semiparametric
  models

abstract:
  A Bernstein-von Mises theorem is derived for general semiparametric
functionals. The result is applied to a variety of semiparametric problems in
i.i.d. and non-i.i.d. situations. In particular, new tools are developed to
handle semiparametric bias, in particular for nonlinear functionals and in
cases where regularity is possibly low. Examples include the squared $L^2$-norm
in Gaussian white noise, nonlinear functionals in density estimation, as well
as functionals in autoregressive models. For density estimation, a systematic
study of BvM results for two important classes of priors is provided, namely
random histograms and Gaussian process priors.


title: PSR B1133+16: radio emission height and plasma composition

abstract:
  Recent operation of LOFAR by Hassall et al has produced severe constraints on
the size and altitude of the 40 MHZ emission region in this pulsar. It is shown
that these limits, given a limited number of unexceptionable assumptions,
demonstrate that an electron-positron plasma cannot be the source of the
emission. A physically-acceptable plasma source composed of protons and ions
arises naturally in pulsars having positive corotational polar-cap charge
density. Acceptance of this would greatly clarify the classification of pulsar
types within the whole.


title: Aleksandrov-Fenchel inequality for coconvex bodies

abstract:
  We prove a version of the Aleksandrov-Fenchel inequality for mixed volumes of
coconvex bodies. This version is motivated by an inequality from commutative
algebra relating intersection multiplicities of ideals.


title:
Evolution of Thermally Pulsing Asymptotic Giant Branch Stars I. The
  COLIBRI Code

abstract:
  We present the COLIBRI code for computing the evolution of stars along the
TP-AGB phase. Compared to purely synthetic TP-AGB codes, COLIBRI relaxes a
significant part of their analytic formalism in favour of a detailed physics
applied to a complete envelope model, in which the stellar structure equations
are integrated from the atmosphere down to the bottom of the hydrogen-burning
shell. This allows to predict self-consistently: (i) the effective temperature,
and more generally the convective envelope and atmosphere structures, correctly
coupled to the changes in the surface chemical abundances and gas opacities;
(ii) sphericity effects in the atmospheres; (iii) the core mass-luminosity
relation and its break-down due to hot bottom burning (HBB) in the most massive
AGB stars, (iv) the HBB nucleosynthesis via the solution of a complete nuclear
network (pp chains, and the CNO, NeNa, MgAl cycles), including also the
production of 7Li via the Cameron-Fowler beryllium transport mechanism; (v) the
chemical composition of the pulse-driven convective zone; (vi) the onset and
quenching of the third dredge-up, with a suitable temperature criterion. At the
same time COLIBRI pioneers new techniques in the treatment of the physics of
stellar interiors. It is the first evolutionary code ever to use accurate
on-the-fly computation of the equation of state for roughly 800 atoms, ions,
molecules, and of the Rosseland mean opacities throughout the deep envelope.
Another distinguishing aspect of COLIBRI is its high computational speed. This
feature is necessary for calibrating the uncertain parameters and processes
that characterize the TP-AGB phase, a step of paramount importance for
producing reliable stellar population synthesis models of galaxies up to high
redshift. (abridged)


title:
A parametric study on the buckling of functionally graded material
  plates with internal discontinuities using the partition of unity method

abstract:
  In this paper, the effect of local defects, viz., cracks and cutouts on the
buckling behaviour of functionally graded material plates subjected to
mechanical and thermal load is numerically studied. The internal
discontinuities, viz., cracks and cutouts are represented independent of the
mesh within the framework of the extended finite element method and an enriched
shear flexible 4-noded quadrilateral element is used for the spatial
discretization. The properties are assumed to vary only in the thickness
direction and the effective properties are estimated using the Mori-Tanaka
homogenization scheme. The plate kinematics is based on the first order shear
deformation theory. The influence of various parameters, viz., the crack length
and its location, the cutout radius and its position, the plate aspect ratio
and the plate thickness on the critical buckling load is studied. The effect of
various boundary conditions is also studied. The numerical results obtained
reveal that the critical buckling load decreases with increase in the crack
length, the cutout radius and the material gradient index. This is attributed
to the degradation in the stiffness either due to the presence of local defects
or due to the change in the material composition.


title: X(3872) and its Partners in the Heavy Quark Limit of QCD

abstract:
  In this letter, we propose interpolating currents for the X(3872) resonance,
and show that, in the Heavy Quark limit of QCD, the X(3872) state should have
degenerate partners, independent of its internal structure. Magnitudes of
possible I=0 and I=1 components of the X(3872) are also discussed.


title: Information erasure in copolymers

abstract:
  Information erasure at the molecular scale during the depolymerization of
copolymers is shown to require a minimum entropy production in accordance with
Landauer's principle and as a consequence of the second law of thermodynamics.
This general result is illustrated with an exactly solvable model of
copolymerization, which also shows that the minimum entropy production that is
possible for a specific molecular mechanism of depolymerization may be larger
than the minimum required by Landauer's principle.


title: Asymmetric Ejecta Distribution in SN 1006

abstract:
  We present the results from deep X-ray observations (~400 ks in total) of SN
1006 by the X-ray astronomy satellite Suzaku. The thermal spectrum from the
entire supernova remnant (SNR) exhibits prominent emission lines of O, Ne, Mg,
Si, S, Ar, Ca, and Fe. The observed abundance pattern in the ejecta components
is in good agreement with that predicted by a standard model of Type Ia
supernovae (SNe). The spatially resolved analysis reveals that the distribution
of the O-burning and incomplete Si-burning products (Si, S, and Ar) is
asymmetric, while that of the C-burning products (O, Ne, and Mg) is relatively
uniform in the SNR interior. The peak position of the former is clearly shifted
by 5' (~3.2 pc at a distance of 2.2 kpc) to the southeast from the SNR's
geometric center. Using the SNR age of ~1000 yr, we constrain the velocity
asymmetry (in projection) of ejecta to be ~3100 km/s. The abundance of Fe is
also significantly higher in the southeast region than in the northwest region.
Given that the non-uniformity is observed only among the heavier elements (Si
through Fe), we argue that SN 1006 originates from an asymmetric explosion, as
is expected from recent multi-dimensional simulations of Type Ia SNe, although
we cannot eliminate the possibility that an inhomogeneous ambient medium
induced the apparent non-uniformity. Possible evidence for the Cr K-shell line
and line broadening in the Fe K-shell emission is also found.


title:
Identification of vortexes obstructing the dynamo mechanism in
  laboratory experiments

abstract:
  The magnetohydrodynamic dynamo effect explains the generation of
self-sustained magnetic fields in electrically conducting flows, especially in
geo- and astrophysical environments. Yet the details of this mechanism are
still unknown, e.g., how and to which extent the geometry, the fluid topology,
the forcing mechanism and the turbulence can have a negative effect on this
process. We report on numerical simulations carried out in spherical geometry,
analyzing the predicted velocity flow with the so-called Singular Value
Decomposition, a powerful technique that allows us to precisely identify
vortexes in the flow which would be difficult to characterize with conventional
spectral methods. We then quantify the contribution of these vortexes to the
growth rate of the magnetic energy in the system. We identify an axisymmetric
vortex, whose rotational direction changes periodically in time, and whose
dynamics are decoupled from those of the large scale background flow, is
detrimental for the dynamo effect. A comparison with experiments is carried
out, showing that similar dynamics were observed in cylindrical geometry. These
previously unexpected eddies, which impede the dynamo effect, offer an
explanation for the experimental difficulties in attaining a dynamo in
spherical geometry.


title: Classical Structures Based on Unitaries

abstract:
  Starting from the observation that distinct notions of copying have arisen in
different categorical fields (logic and computation, contrasted with quantum
mechanics) this paper addresses the question of when, or whether, they may
coincide. Provided all definitions are strict in the categorical sense, we show
that this can never be the case. However, allowing for the defining axioms to
be taken up to canonical isomorphism, a close connection between the classical
structures of categorical quantum mechanics, and the categorical property of
self-similarity familiar from logical and computational models becomes
apparent.
  The required canonical isomorphisms are non-trivial, and mix both typed
(multi-object) and untyped (single-object) tensors and structural isomorphisms;
we give coherence results that justify this approach.
  We then give a class of examples where distinct self-similar structures at an
object determine distinct matrix representations of arrows, in the same way as
classical structures determine matrix representations in Hilbert space. We also
give analogues of familiar notions from linear algebra in this setting such as
changes of basis, and diagonalisation.


title: The shark teeth is a topological IFS-attractor

abstract:
  We show that the space called shark teeth is a topological IFS-attractor,
that is for every open cover of $X=\bigcup_{i=1}^nf_i(X)$, its image under
every suitable large composition from the family of continuous functions
$\{f_1,...,f_n\}$ lies in some set from the cover. In particular, there exists
a space which is not homeomorphic to any IFS-attractor but is a topological
IFS-attractor.


title: Bohr space in six dimensions

abstract:
  A conformal factor in the Bohr model embeds Bohr space in six dimensions,
revealing the $O(6)$ symmetry and its contraction to the $E(5)$ at infinity.
Phenomenological consequences are discussed after the re-formulation of the
Bohr Hamiltonian in six dimensions on a five sphere.


title: Spin-Triplet Pairing State of Sr2RuO4 in the c-Axis Magnetic Field

abstract:
  We investigate the spin-triplet superconducting state of Sr2RuO4 in the
magnetic field along the c-axis on the basis of the four-component
Ginzburg-Landau (GL) model with a weak spin-orbit coupling. We consider
superconducting states described by the d-vector parallel to the ab-plane, and
find that three spin-triplet pairing states are stabilized in the magnetic
field-temperature phase diagram. Although a helical state is stable at low
magnetic fields, a chiral II state is stabilized at high magnetic fields. A
non-unitary spin-triplet pairing state appears near the transition temperature
owing to the coupling of magnetic field and chirality. We elucidate synergistic
and/or competing roles of the magnetic field, chirality, and spin-orbit
coupling. It is shown that a fractional vortex lattice is stabilized in the
chiral II phase owing to the spin-orbit coupling.


title:
Right inverses for partial differential operators on spaces of Whitney
  functions

abstract:
  For v\in R^n let K be a compact set in R^n containing a suitable smooth
surface and such that the intersection {tv+x:t\in R}\cap K is a closed interval
or a single point for all x\in K. We prove that every linear first order
differential operator with constant coefficients in direction v on space of
Whitney functions E(K) admits a continuous linear right inverse.


title:
Covariance inflation in the ensemble Kalman filter: a residual nudging
  perspective and some implications

abstract:
  This note examines the influence of covariance inflation on the distance
between the measured observation and the simulated (or predicted) observation
with respect to the state estimate. In order for the aforementioned distance to
be bounded in a certain interval, some sufficient conditions are derived,
indicating that the covariance inflation factor should be bounded in a certain
interval, and that the inflation bounds are related to the maximum and minimum
eigenvalues of certain matrices. Implications of these analytic results are
discussed, and a numerical experiment is presented to verify the validity of
our analysis.

categories: physics.ao-ph math.OC math.ST nlin.CD stat.ME stat.TH


title:
Observation of magnetically hard grain boundaries in double-perovskite
  Sr$_{2}$FeMoO$_{6}$

abstract:
  Unusual low temperature magneto-resistance (MR) of ferromagnetic
Sr$_{2}$FeMoO$_{6}$ polycrystals has been attributed to magnetically hard grain
boundaries which act as spin valves. We detected the different magnetic
hysteresis curves for the grains and the grain boundaries of polycrystalline
Sr$_{2}$FeMoO$_{6}$ by utilizing the different probing depths of the different
detection modes of x-ray absorption spectroscopy (XAS) and x-ray magnetic
circular dichroism (XMCD), namely, the total electron yield (TEY) mode (probing
depth $\sim$5 nm) and the total fluorescence yield (TFY) mode (probing depth
$\sim$100 nm). At 20 K, the magnetic coercivity detected in the TEY mode
($H_{\rm c,TEY}$) was several times larger than that in the TFY mode ($H_{\rm
c,TFY}$), indicating harder ferromagnetism of the grain boundaries than that of
the grains. At room temperature, the grain boundary magnetism became soft and
$H_{\rm c,TEY}$ and $H_{\rm c,TFY}$ were nearly the same. From line-shape
analysis of the XAS and XMCD spectra, we found that in the grain boundary
region the ferromagnetic component is dominated by Fe$^{2+}$ or well-screened
signals while the non-magnetic component is dominated by Fe$^{3+}$ or
poorly-screened signals.


title:
A note on "Sur le noyau de l'op\'{e}rateur de courbure d'une
  vari\'{e}t\'{e} finsl\'{e}rienne" [C. R. Acad. Sci. Paris, t. 272 (1971),
  807-810]

abstract:
  In this note, adopting the pullback formalism of global Finsler geometry, we
show by a counterexample that the kernel $\text{Ker}_R$ of the h-curvature $R$
of Cartan connection and the associated nullity distribution $\N_R$ do not
coincide, contrary to Akbar-Zadeh's result \cite{akbar.nul3.}. We give
sufficient conditions for $\text{Ker}_R$ and $\N_R$ to coincide.


title: Control of decoherence with no control

abstract:
  Common philosophy in control theory is the control of disorder by order. It
is not exceptional for strategies suppressing quantum decoherence. Here we
predict an anomalous quantum phenomenon. Suppression of decoherence can be made
via more disordered white noise field, in particular white Poissonian noise.
The phenomenon seems to be another anomaly in quantum mechanics, and may offer
a new strategy in quantum control practices.


title: Cauchy theorem for a surface integral in commutative algebras

abstract:
  We prove an analogue of the Cauchy integral theorem for hyperholomorphic
functions given in three-dimensional domains with non piece-smooth boundaries
and taking values in an arbitrary finite-dimensional commutative associative
Banach algebra.


title: Bielliptic curves of genus 3 in the hyperelliptic moduli

abstract:
  In this paper we study bielliptic curves of genus 3 defined over an
algebraically closed field $k$ and the intersection of the moduli space
$\M_3^b$ of such curves with the hyperelliptic moduli $\H_3$. Such intersection
$\S$ is an irreducible, 3-dimensional, rational algebraic variety. We determine
the equation of this space in terms of the $Gl(2, k)$-invariants of binary
octavics as defined in \cite{hyp_mod_3} and find a birational parametrization
of $\S$. We also compute all possible subloci of curves for all possible
automorphism group $G$. Moreover, for every rational moduli point $\p \in \S$,
such that $| \Aut (\p) | > 4$, we give explicitly a rational model of the
corresponding curve over its field of moduli in terms of the $Gl(2,
k)$-invariants.


title: Recent Results from the ANTARES Neutrino Telescope 2013

abstract:
  The ANTARES experiment is currently the largest underwater neutrino
telescope. It is taking high quality data since 2007 and aims to detect high
energy neutrinos that are expected from the acceleration of cosmic rays from
astrophysical sources. We will review the status of the detector and present
several analyses carried out on atmospheric muons and neutrinos. For example we
will show the latest results from searches for neutrinos from steady cosmic
point-like sources, for neutrinos from Fermi Bubbles, for neutrinos from Dark
Matter in the Sun and the measurement of atmospheric neutrino oscillation
parameters.


title:
Stochastic perturbation of integrable systems: a window to weakly
  chaotic systems

abstract:
  Integrable non-linear Hamiltonian systems perturbed by additive noise develop
a Lyapunov instability, and are hence chaotic, for any amplitude of the
perturbation. This phenomenon is related, but distinct, from Taylor's diffusion
in hydrodynamics. We develop expressions for the Lyapunov exponents for the
cases of white and colored noise. The situation described here being
`multi-resonance' -- by nature well beyond the Kolmogorov-Arnold-Moser regime,
it offers an analytic glimpse on the regime in which many near-integrable
systems, such as some planetary systems, find themselves in practice. We show
with the aid of a simple example, how one may model in some cases weakly
chaotic deterministic systems by a stochastically perturbed one, with good
qualitative results.

categories: nlin.CD cond-mat.stat-mech math-ph math.DS math.MP


title:
Evanescent straight tapered-fiber coupling of ultra-high Q
  optomechanical micro-resonators in a low-vibration helium-4 exchange-gas
  cryostat

abstract:
  We developed an apparatus to couple a 50-micrometer diameter
whispering-gallery silica microtoroidal resonator in a helium-4 cryostat using
a straight optical tapered-fiber at 1550nm wavelength. On a top-loading probe
specifically adapted for increased mechanical stability, we use a
specifically-developed "cryotaper" to optically probe the cavity, allowing thus
to record the calibrated mechanical spectrum of the optomechanical system at
low temperatures. We then demonstrate excellent thermalization of a 63-MHz
mechanical mode of a toroidal resonator down to the cryostat's base temperature
of 1.65K, thereby proving the viability of the cryogenic refrigeration via heat
conduction through static low-pressure exchange gas. In the context of
optomechanics, we therefore provide a versatile and powerful tool with
state-of-the-art performances in optical coupling efficiency, mechanical
stability and cryogenic cooling.


title: Computing points on modular curves over finite fields

abstract:
  In this paper, we present a probabilistic algorithm to compute the number of
$\mathbb{F}_p$-points of modular curve $X_1(n)$. Under the Generalized Riemann
Hypothesis(GRH), the algorithm takes
$\textrm{O}(n^{56+\delta+\epsilon}\log^{9+\epsilon} p)$ bit operations, where
$\delta$ is an absolute constant and $\epsilon$ is any positive real number. As
an application, we can compute $#X_1(17)(\mathbb{F}_p)\textrm{mod} 17$ for huge
primes $p$. For example, we have
$#X_1(17)(\mathbb{F}_{10^{1000}+1357})\textrm{mod} 17=3$.


title:
Predicting coexistence of plants subject to a tolerance-competition
  trade-off

abstract:
  Ecological trade-offs between species are often invoked to explain species
coexistence in ecological communities. However, few mathematical models have
been proposed for which coexistence conditions can be characterized explicitly
in terms of a trade-off. Here we present a model of a plant community which
allows such a characterization. In the model plant species compete for sites
where each site has a fixed stress condition. Species differ both in stress
tolerance and competitive ability. Stress tolerance is quantified as the
fraction of sites with stress conditions low enough to allow establishment.
Competitive ability is quantified as the propensity to win the competition for
empty sites. We derive the deterministic, discrete-time dynamical system for
the species abundances. We prove the conditions under which plant species can
coexist in a stable equilibrium. We show that the coexistence conditions can be
characterized graphically, clearly illustrating the trade-off between stress
tolerance and competitive ability. We compare our model with a recently
proposed, continuous-time dynamical system for a tolerance-fecundity trade-off
in plant communities, and we show that this model is a special case of the
continuous-time version of our model.


title:
Boundary Localized Terms in Universal Extra-Dimensional Models through a
  Dark Matter perspective

abstract:
  In universal extra dimension (UED) models with one compactified extra
dimension, a Z_2 symmetry, termed KK-parity, ensures the stability of the
lightest Kaluza-Klein particle (LKP). This symmetry leads to two fixed points.
In non-minimal versions of UED boundary-localised terms (BLT) for different
fields are included at these fixed points and KK-parity may be violated.
However, BLTs with same strength at both points induce a new Z_2 symmetry which
restores the stability of the LKP. We show that the BLTs serve to relax the
bounds set on the compactification scale in UED by the dark matter relic
density requirement. At the same time, the precision of the dark matter
measurements severely correlates the BLT parameters of gauge bosons and
fermions. Depending on the parameter values, the LKP can be chosen to be the
level-1 photon, which is essentially the B^(1), or the level-1 Z-boson,
basically the W_3^(1). We find that in the latter case the relic density is too
small for a W_3^(1) with a \sim 1 TeV mass. We also explore the prospects of
direct detection of an LKP which matches the observed dark matter relic
density.


title: Quadratic Residue Codes over F_p+vF_p and their Gray Images

abstract:
  In this paper quadratic residue codes over the ring Fp + vFp are introduced
in terms of their idempotent generators. The structure of these codes is
studied and it is observed that these codes share similar properties with
quadratic residue codes over finite fields. For the case p = 2, Euclidean and
Hermitian self-dual families of codes as extended quadratic residue codes are
considered and two optimal Hermitian self-dual codes are obtained as examples.
Moreover, a substantial number of good p-ary codes are obtained as images of
quadratic residue codes over Fp +vFp in the cases where p is an odd prime.
These results are presented in tables.


title:
Clustering of quintessence on horizon scales and its imprint on HI
  intensity mapping

abstract:
  Quintessence can cluster only on horizon scales. What is the effect on the
observed matter distribution? To answer this, we need a relativistic approach
that goes beyond the standard Newtonian calculation and deals properly with
large scales. Such an approach has recently been developed for the case when
dark energy is vacuum energy, which does not cluster at all. We extend this
relativistic analysis to deal with dynamical dark energy. Using three
quintessence potentials as examples, we compute the angular power spectrum for
the case of an HI intensity map survey. Compared to the concordance model with
the same small-scale power at z=0, quintessence boosts the angular power by up
to ~15% at high redshifts, while power in the two models converges at low
redshifts. The difference is mainly due to the background evolution, driven
mostly by the normalization of the power spectrum today. The dark energy
perturbations make only a small contribution on the largest scales, and a
negligible contribution on smaller scales. Ironically, the dark energy
perturbations remove the false boost of large-scale power that arises if we
impose the (unphysical) assumption that the dark energy is smooth.


title: A renormalization group approach for QCD in a strong magnetic field

abstract:
  A Wilsonian renormalization group approach is applied, in order to include
effects of the higher Landau levels for quarks into a set of renormalized
parameters for the lowest Landau level (LLL), plus a set of operators made of
the LLL fields. Most of the calculations can be done in a model-independent way
with perturbation theory for hard gluons, thanks to form factors of quark-gluon
vertices that arise from the Ritus bases for quark fields. As a part of such
renormalization program, we compute the renormalized quark self-energy at
1-loop, including effects from all higher orbital levels. The result indicates
that the higher orbital levels cease to strongly affect the LLL at a rather
small magnetic field of (0.1 - 0.3) GeV^2.


title:
Bayesian Multi--Dipole Modeling of a Single Topography in MEG by
  Adaptive Sequential Monte Carlo Samplers

abstract:
  In the present paper, we develop a novel Bayesian approach to the problem of
estimating neural currents in the brain from a fixed distribution of magnetic
field (called \emph{topography}), measured by magnetoencephalography.
Differently from recent studies that describe inversion techniques, such as
spatio-temporal regularization/filtering, in which neural dynamics always plays
a role, we face here a purely static inverse problem. Neural currents are
modelled as an unknown number of current dipoles, whose state space is
described in terms of a variable--dimension model. Within the resulting
Bayesian framework, we set up a sequential Monte Carlo sampler to explore the
posterior distribution. An adaptation technique is employed in order to
effectively balance the computational cost and the quality of the sample
approximation. Then, both the number and the parameters of the unknown current
dipoles are simultaneously estimated. The performance of the method is assessed
by means of synthetic data, generated by source configurations containing up to
four dipoles. Eventually, we describe the results obtained by analyzing data
from a real experiment, involving somatosensory evoked fields, and compare them
to those provided by three other methods.


title: Loop quantum cosmology for nonminimally coupled scalar field

abstract:
  We perform a LQC-quantization of the FRW cosmological model with nonminimally
coupled scalar field. Making use of a canonical transformation, we recast the
theory in the minimally coupled form (Einstein frame), for which standard LQC
techniques can be applied to find the physical Hilbert space and the dynamics.
We then focus on the semiclassical sector, obtaining a classical effective
Hamiltonian, which can be used to study the dynamics. We show that the
classical singularity is replaced by a "mexican hat"-shaped bounce, joining the
contracting and expanding branches. The model accommodates Higgs-driven
inflation, with more than enough e-folding for any physically meaningful
initial condition.


title: Quantum field theory on LQC Bianchi spacetimes

abstract:
  Quantum theory of a scalar field is developed on the LQC Bianchi I
space-time. By comparing the the quantum field theory for a single mode on
classical and quantum background geometries we find that an effective Bianchi I
space-time emerges. We show that by disregarding the back-reaction no
Lorentz-violation is present, despite the effective metric being different than
the classical Bianchi I one.


title: Fluid motion induced by surface waves at low Reynolds number

abstract:
  We discuss the scaling laws for the flow generated in a viscous fluid by a
wave propagating along a solid boundary. This has applications to the
displacement of tiny objects on solids, under the effect of progressive surface
waves and for the swimming of microanimals by undulation of ciliae along their
body surface.


title: Extensions of topological Abelian groups and three-space problems

abstract:
  A twisted sum in the category of topological abelian groups is a short exact
sequence $0\to Y\to X \to Z\to 0$ where all maps are assumed to be continuous
and open onto their images. The twisted sum splits if it is equivalent to $0\to
Y\to Y \times Z \to Z\to 0$. \par We study the class $\ST$ of topological
groups $G$ for which every twisted sum $0\to \T\to X \to G\to 0$ splits. We
prove that this class contains locally precompact groups, sequential direct
limits of locally compact groups and topological groups with
$\mathcal{L}_\infty$ topologies. We also prove that it is closed by taking open
and dense subgroups, quotients by dually embedded subgroups and coproducts. As
a technique to find further examples of groups in $\ST$ we use the relation of
this class with the existence of quasi-characters on $G$ and with three-space
problems for topological groups. The subject is inspired on some concepts known
in the framework of topological vector spaces such as the notion of $K$-space,
which were interpreted for topological groups by Cabello.


title:
Modified Friedmann equation and survey of solutions in effective
  Bianchi-I loop quantum cosmology

abstract:
  In this article, we study the equations driving the dynamics of a Bianchi-I
universe described by holonomy corrected effective loop quantum cosmology. We
derive the LQC-modified generalized Friedmann equation, which is used as a
guide to find different types of solutions. It turns out that, in this
framework, most solutions never reach the classical behavior.


title:
Phase-field study on the segregation mechanism of Cr to lamellar
  interface in C40-NbSi2/C11b-MoSi2 duplex silicide

abstract:
  Cr-segregation to a lamellar interface in NbSi2/MoSi2 duplex silicide has
been examined by a newly developed phase-field model. The model can take into
account the segregation energy evaluated by a first principles calculation to
reflect the chemical interaction between solute atoms and the interface in
addition to the elastic interaction. Cr segregation occurs at the interface in
the case with segregation energy whereas no segregation occurs in the case with
only elastic interaction. However, the segregation is much smaller than that
observed in the experiment when the segregation energy was evaluated by the
first principles calculation without lattice vibration (i.e. for 0 K). Another
simulations with the segregation energy with lattice vibration results in
segregation comparable to that in the experiment. Thus, it has been revealed
that the solute-interface chemical interaction and its temperature dependence
is responsible for the interfacial segregation of Cr.


title:
Canonical quantization of classical mechanics in curvilinear
  coordinates. Invariant quantization procedure

abstract:
  In the paper is presented an invariant quantization procedure of classical
mechanics on the phase space over flat configuration space. Then, the passage
to an operator representation of quantum mechanics in a Hilbert space over
configuration space is derived. An explicit form of position and momentum
operators as well as their appropriate ordering in arbitrary curvilinear
coordinates is demonstrated. Finally, the extension of presented formalism onto
non-flat case and related ambiguities of the process of quantization are
discussed.


title: Clustered planarity testing revisited

abstract:
  The Hanani--Tutte theorem is a classical result proved for the first time in
the 1930s that characterizes planar graphs as graphs that admit a drawing in
the plane in which every pair of edges not sharing a vertex cross an even
number of times. We generalize this result to clustered graphs with two
disjoint clusters, and show that a straightforward extension to flat clustered
graphs with three or more disjoint clusters is not possible. For general
clustered graphs we show a variant of the Hanani--Tutte theorem in the case
when each cluster induces a connected subgraph. Di Battista and Frati proved
that clustered planarity of embedded clustered graphs whose every face is
incident with at most five vertices can be tested in polynomial time. We give a
new and short proof of this result, using the matroid intersection algorithm.


title: Strengthening weak value amplification with recycled photons

abstract:
  We consider the use of cyclic weak measurements to improve the sensitivity of
weak-value amplification precision measurement schemes. Previous weak-value
experiments have used only a small fraction of events, while discarding the
rest through the process of "post-selection". We extend this idea by
considering recycling of events which are typically unused in a weak
measurement. Here we treat a sequence of polarized laser pulses effectively
trapped inside an interferometer using a Pockels cell and polarization optics.
In principle, all photons can be post-selected, which will improve the
measurement sensitivity. We first provide a qualitative argument for the
expected improvements from recycling photons, followed by the exact result for
the recycling of collimated beam pulses, and numerical calculations for
diverging beams. We show that beam degradation effects can be mitigated via
profile flipping or Zeno reshaping. The main advantage of such a recycling
scheme is an effective power increase, while maintaining an amplified
deflection.


title:
Loop Suppression of Dirac Neutrino Mass in the Neutrinophilic Two Higgs
  Doublet Model

abstract:
  We extend the scalar sector of the neutrinophilic two Higgs doublet model,
where small masses of Dirac neutrinos are obtained via a small vacuum
expectation value v_nu of the neutrinophilic SU(2)_L-doublet scalar field which
has a Yukawa interaction with only right-handed neutrinos. A global U(1)_X
symmetry is used for the neutrinophilic nature of the second SU(2)_L-doublet
scalar field and also for eliminating Majorana mass terms of neutrinos. By
virtue of an appropriate assignment of the U(1)_X-charges to new particles, our
model has an unbroken Z_2 symmetry, under which the lightest Z_2-odd scalar
boson can be a dark matter candidate. In our model, v_nu is generated by the
one-loop diagram to which Z_2-odd particles contribute. We briefly discuss a
possible signature of our model at the LHC.


title: Nonlocal Asymmetric exclusion process on a ring and conformal invariance

abstract:
  We present a one-dimensional nonlocal hopping model with exclusion on a ring.
The model is related to the Raise and Peel growth model. A nonnegative
parameter $u$ controls the ratio of the local backwards and nonlocal forwards
hopping rates. The phase diagram and consequently the values of the current,
depend on $u$ and the density of particles. In the special case of half-filling
and $u = 1$ the system is conformal invariant and an exact value of the current
for any size $L$ of the system is conjectured and checked for large lattice
sizes in Monte Carlo simulations. For $u > 1$ the current has a non-analytic
dependence on the density when the latter approaches the half-filling value.


title: A model theoretic construction for layered semifields

abstract:
  In this paper we introduce a model theoretic construction for the theories of
uniform layered domains and semifields introduced in the paper of Izhakian,
Knebusch and Rowen. We prove that, for a given layering semiring L, the theory
of uniform L-layered divisibly closed semifields is complete. In the process of
doing so, we prove that this theory has quantifier elimination and consequently
is model complete. Model completeness of uniform L-layered divisibly closed has
some important consequences regarding the uniform L-layered semifields theory.
One example involves equating polynomials. Namely, model completeness insures
us that if two polynomials are equal over a divisibly closed uniform L-layered
semifield, then they are equal over any divisibly closed uniform L-layered
extension of that semifield, and thus over any uniform L-layered domain
extending the semifield (as it is contained in its divisible closure of its
semifield of fractions). At the end of this paper we apply our results to the
theory of max-plus algebras as a special case of uniform L -layered domains.


title: The Black Hole Particle Accelerator as a Machine to make Baby Universes

abstract:
  General relativity predicts that the inner horizon of an astronomically
realistic rotating black hole is subject to the mass inflation instability. The
inflationary instability acts like a gravity-powered particle accelerator of
extraordinary power, accelerating accreted streams of particles along the
principal outgoing and ingoing null directions at the inner horizon to
collision energies that would, if nothing intervened, typically exceed
exponentially the Planck energy. The inflationary instability is fueled by
ongoing accretion, and is occurring inevitably in essentially every black hole
in our Universe. This extravagant machine, the Black Hole Particle Accelerator,
has the hallmarks of a device to make baby universes. Since collisions are most
numerous inside supermassive black holes, reproductive efficiency requires our
Universe to make supermassive black holes efficiently, as is observed.


title: Robustness of Random Forest-based gene selection methods

abstract:
  Gene selection is an important part of microarray data analysis because it
provides information that can lead to a better mechanistic understanding of an
investigated phenomenon. At the same time, gene selection is very difficult
because of the noisy nature of microarray data. As a consequence, gene
selection is often performed with machine learning methods. The Random Forest
method is particularly well suited for this purpose. In this work, four
state-of-the-art Random Forest-based feature selection methods were compared in
a gene selection context. The analysis focused on the stability of selection
because, although it is necessary for determining the significance of results,
it is often ignored in similar studies.
  The comparison of post-selection accuracy in the validation of Random Forest
classifiers revealed that all investigated methods were equivalent in this
context. However, the methods substantially differed with respect to the number
of selected genes and the stability of selection. Of the analysed methods, the
Boruta algorithm predicted the most genes as potentially important.
  The post-selection classifier error rate, which is a frequently used measure,
was found to be a potentially deceptive measure of gene selection quality. When
the number of consistently selected genes was considered, the Boruta algorithm
was clearly the best. Although it was also the most computationally intensive
method, the Boruta algorithm's computational demands could be reduced to levels
comparable to those of other algorithms by replacing the Random Forest
importance with a comparable measure from Random Ferns (a similar but
simplified classifier). Despite their design assumptions, the minimal optimal
selection methods, were found to select a high fraction of false positives.


title:
Variables suitable for constructing quantum states for the Teleparallel
  Equivalent of General Relativity I

abstract:
  We present the first part of an analysis aimed at introducing variables which
are suitable for constructing a space of quantum states for the Teleparallel
Equivalent of General Relativity via projective techniques - the space is meant
to be applied in a canonical quantization of the theory. We show that natural
configuration variables on the phase space of the theory can be used to
construct a space of quantum states which however possesses an undesired
property. We introduce then a family of new variables such that some elements
of the family can be applied to build a space of quantum states free of that
property.


title: Quantum information-geometry of dissipative quantum phase transitions

abstract:
  A general framework for analyzing the recently discovered phase transitions
in the steady state of dissipation-driven open quantum systems is still
missing. In order to fill this gap we extend the so-called fidelity approach to
quantum phase transitions to open systems whose steady state is a Gaussian
Fermionic state. We endow the manifold of correlations matrices of
steady-states with a metric tensor g measuring the distinguishability distance
between solutions corresponding to different set of control parameters. The
phase diagram can be then mapped out in terms of the scaling-behavior of g and
connections with the Liouvillean gap and the model correlation functions
unveiled. We argue that the fidelity approach, thanks to its
differential-geometric and information-theoretic nature, provides novel
insights on dissipative quantum critical phenomena as well as a general and
powerful strategy to explore them.


title:
Statistical distribution of current helicity in solar active regions
  over the magnetic cycle

abstract:
  The current helicity in solar active regions derived from vector magnetograph
observations for more than 20 years indicates the so-called hemispheric sign
rule; the helicity is predominantly negative in the northern hemisphere and
positive in the southern hemisphere. In this paper we revisit this property and
compare the statistical distribution of current helicity with Gaussian
distribution using the method of normal probability paper. The data sample
comprises 6630 independent magnetograms obtained at Huairou Solar Observing
Station, China, over 1988-2005 which correspond to 983 solar active regions. We
found the following. (1) For the most of cases in time-hemisphere domains the
distribution of helicity is close to Gaussian. (2) At some domains (some years
and hemispheres) we can clearly observe significant departure of the
distribution from a single Gaussian, in the form of two- or multi-component
distribution. (3) For the most non-single-Gaussian parts of the dataset we see
co-existence of two or more components, one of which (often predominant) has a
mean value very close to zero, which does not contribute much to the
hemispheric sign rule. The other component has relatively large value of
helicity that often determines agreement or disagreement with the hemispheric
sign rule in accord with the global structure of helicity reported by Zhang et
al. (2010).


title: Non-strictly black body spectrum from the tunnelling mechanism

abstract:
  A modern and largely used approach to obtain Hawking radiation is the
tunnelling mechanism. However, in various papers in the literature, the
analysis concerned almost only to obtain the Hawking temperature through a
comparison of the probability of emission of an outgoing particle with the
Boltzmann factor. In a interesting and well written paper, Banerjee and Majhi
improved the approach, by explicitly finding a black body spectrum associated
with black holes. On the other hand, this result, which has been obtained by
using a reformulation of the tunnelling mechanism, is in contrast which the
remarkable result by Parikh and Wilczek, that, indeed, found a probability of
emission which is compatible with a non-strictly thermal spectrum. By using our
recent introduction of an effective state for a black hole, here we solve such
a contradiction, through a slight modification of the analysis by Banerjee and
Majhi. The final result will be a non-strictly black body spectrum from the
tunnelling mechanism. We also show that, for an effective temperature, we can
write the corresponding effective metric by Hawking's periodicity arguments.
Potential important implications for the black hole information puzzle are also
discussed


title: ISW effect as probe of features in the expansion history of the Universe

abstract:
  In this paper, using and implementing a new line of sight CMB code, called
CMBAns [1], that allows us to modify H(z) for any given feature at any redshift
we study the effect of changes in the expansion history of the Universe on the
CMB power spectrum. Motivated by the detailed analytical calculations of the
effects of the changes in H(z) on ISW plateau and CMB low multipoles, we study
two phenomenological parametric form of the expansion history using WMAP data
and through MCMC analysis. Our MCMC analysis shows that the standard LCDM
cosmological model is consistent with the CMB data allowing the expansion
history of the Universe vary around this model at different redshifts. However,
our analysis also shows that a decaying dark energy model proposed in [2] has
in fact a marginally better fit than the standard cosmological constant model
to CMB data. Concordance of our studies here with the previous analysis showing
that Baryon Acoustic Oscillation (BAO) and supernovae data (SN Ia) also prefer
mildly this decaying dark energy model to LCDM, makes this finding interesting
and worth further investigation.


title: Dynamic Brittle Fracture as a Small Horizon Limit of Peridynamics

abstract:
  We consider the nonlocal formulation of continuum mechanics described by
peridynamics. We provide a link between peridynamic evolution and brittle
fracture evolution for a broad class of peridynamic potentials associated with
unstable peridynamic constitutive laws. Distinguished limits of peridynamic
evolutions are identified that correspond to vanishing peridynamic horizon. The
limit evolution is associated with dynamic brittle fracture and satisfies a
dynamic energy inequality expressed in terms of the kinetic energy of the
motion together with a bulk elastic energy and a Griffith surface energy. It
corresponds to the simultaneous evolution of elastic displacement and brittle
fracture with displacement fields satisfying the wave equation inside the
cracking domain. The wave equation provides the dynamic coupling between
elastic waves and the evolving fracture path inside the media. The elastic
moduli, wave speed and energy release rate for the evolution are explicitly
determined by moments of the peridynamic influence function and the peridynamic
potential energy.


title: Strongly representable algebras

abstract:
  We give a simpler proof of a result of Hodkinson in the context of a blow and
blur up construction argueing that the idea at heart is similar to that adopted
by Andr\'eka et all \cite{sayed}. The idea is to blow up a finite structure,
replacing each 'colour or atom' by infinitely many, using blurs to represent
the resulting term algebra, but the blurs are not enough to blur the structure
of the finite structure in the complex algebra. A reverse of this process
exists in the literature, it builds algebras with infinite blurs converging to
one with finite blurs. This idea due to Hirsch and Hodkinson, uses
probabilistic methods of Erdos to construct a sequence of graphs with infinite
chromatic number one that is 2 colourable. This construction, which works for
both relation and cylindric algebras, further shows that the class of strongly
representable atom structures is not elementary. We will generalize such a
result for any class of algebras between diagonal free algebras and polyadic
algebras with and without equality, then we further discuss possibilities for
the infinite dimensional case.
  Finally, we suggest a very plausible equivalence, and that is: If $n>2$, is
finite, and $\A\in \CA_n$ is countable and atomic, then $\Cm\At\A$ is
representable if and only if $\A\in \Nr_n\CA_{\omega}$. We could prove one
side.


title: Magnetization of neutron star matter

abstract:
  The magnetization of neutron star matter in magnetic fields is studied by
employing the FSUGold interaction. It is found that the magnetic
susceptibilities of the charged particles (proton, electron and muon) can be
larger than that of neutron. The effects of the anomalous magnetic moments
(AMM) of each component on the magnetic susceptibility are examined in detail.
It is found that the proton and electron AMM affect their respective magnetic
susceptibility evidently in strong magnetic fields. In addition, they are the
protons instead of the electrons that contribute most significantly to the
magnetization of the neutron star matter in a relative weak magnetic field, and
the induced magnetic field due to the magnetization can be appear to be very
large. Finally, the effect of the density-dependent symmetry energy on the
magnetization is discussed.


title:
Effect of tensor correlations on the depletion of nuclear Fermi sea
  within the extended BHF approach

abstract:
  We have investigated the effect of tensor correlations on the depletion of
nuclear Fermi sea in symmetric nuclear matter within the framework of the
extended Brueckner-Hartree-Fock approach by adopting the AV18 two-body
interaction and a microscopic three-body force. The contributions from various
partial wave channels including the isospin-singlet T=0 channel, the
isospin-triplet T=1 channel and the T=0 tensor 3SD1 channel have been
calculated. The T=0 neutron-proton correlations play a dominated role in
causing the depletion of nuclear Fermi sea. The T=0 correlation-induced
depletion turns out to stem almost completely from the $^3SD_1$ tensor channel.
The isospin-singlet T=0 3SD1 tensor correlations is shown to response for most
of the depletion, which amounts to more than 70 percent out of the total
depletion in the density region considered. The TBF turns out to leads to an
enhancement of the depletion at high densities well above the empirical
saturation density and its effect increases as a function of density.


title:
Active Galactic Nucleus and Extended Starbursts in a Mid-stage Merger
  VV114

abstract:
  High resolution (0.4 arcsec) Atacama Large Millimeter/submillimeter Array
(ALMA) Cycle 0 observations of HCO+(4-3) and HCN(4-3) toward a mid-stage
infrared bright merger VV114 have revealed compact nuclear (<200 pc) and
extended (3 - 4 kpc) dense gas distribution across the eastern part of the
galaxy pair. We find a significant enhancement of HCN(4-3) emission in an
unresolved compact and broad (290km/s) component found in the eastern nucleus
of VV114, and we suggest dense gas associated with the surrounding material
around an Active Galactic Nucleus (AGN), with a mass upper limit of < 4 x 10^8
Msun. The extended dense gas is distributed along a filamentary structure with
resolved dense gas concentrations (230pc; 10^6 Msun) separated by a mean
projected distance of 600 pc, many of which are generally consistent with the
location of star formation traced in Pa alpha emission. Radiative transfer
calculations suggest moderately dense (10^5 - 10^6 cm^-3) gas averaged over the
entire emission region. These new ALMA observations demonstrate the strength of
the dense gas tracers in identifying both the AGN and star formation activity
in a galaxy merger, even in the most dust enshrouded environments in the local
universe.


title: Counting homotopy classes of mappings via Dijkgraaf-Witten invariants

abstract:
  Suppose $\Gamma$ is a finite group acting freely on $S^{n}$ ($n\geqslant 3$
being odd) and $M$ is any closed oriented $n$-manifold. We show that, given an
integer $k$, the set $\deg^{-1}(k)$ of based homotopy classes of mappings with
degree $k$ is finite and its cardinality depends only on the congruence class
of $k$ modulo $\#\Gamma$; moreover, $\#\deg^{-1}(k)$ can be expressed in terms
of the Dijkgraaf-Witten invariants of $M$.


title:
Object Detection with Pixel Intensity Comparisons Organized in Decision
  Trees

abstract:
  We describe a method for visual object detection based on an ensemble of
optimized decision trees organized in a cascade of rejectors. The trees use
pixel intensity comparisons in their internal nodes and this makes them able to
process image regions very fast. Experimental analysis is provided through a
face detection problem. The obtained results are encouraging and demonstrate
that the method has practical value. Additionally, we analyse its sensitivity
to noise and show how to perform fast rotation invariant object detection.
Complete source code is provided at https://github.com/nenadmarkus/pico.


title: Proportional Fair MU-MIMO in 802.11 WLANs

abstract:
  We consider the proportional fair rate allocation in an 802.11 WLAN that
supports multi-user MIMO (MU-MIMO) transmission by one or more stations. We
characterise, for the first time, the proportional fair allocation of MU-MIMO
spatial streams and station transmission opportunities. While a number of
features carry over from the case without MU-MIMO, in general neither flows nor
stations need to be allocated equal airtime when MU-MIMO is available.


title: Noncommutative geometry inspired wormholes with conformal motion

abstract:
  This paper discusses a new wormhole solution that admits conformal motion,
given a noncommutative-geometry background. After a discussion of the wormhole
geometry and the energy conditions, the analysis proceeds with the calculation
of the active gravitational mass, a discussion of the TOV equation describing
the equilibrium conditions, as well as the nature of the total gravitational
energy. The wormhole spacetime is not asymptotically flat and is therefore cut
off at some radial distance and joined to an exterior vacuum solution.


title:
Closed oriented 3-manifolds are subtle equivalence classes of plane
  graphs

abstract:
  A {\em blink} is a plane graph with an arbitrary bipartition of its edges. As
a consequence of a recent result of Martelli, I show that the homeomorphisms
classes of closed oriented 3-manifolds are in 1-1 correspondence with specific
classes of blinks. In these classes, two blinks are equivalent if they are
linked by a finite sequence of local moves, where each one appears in a
concrete list of 64 moves: they organize in 8 types, each being essentially the
same move on 8 simply related configurations. The size of the list can be
substantially decreased at the cost of loosing symmetry, just by keeping a very
simple move type, the {\em ribbon moves} denoted $\pm \mu_{11}^{\pm}$ (which
are in principle redundant). The inclusion of $\pm \mu_{11}^{\pm}$ implies that
all the moves corresponding to plane duality (the starred moves), except for
$\mu_{20}^\star$ and $\mu_{02}^\star$, are redundant and the coin calculus is
reduced to 36 moves on 36 coins.
  A {\em residual fraction link} or a {\em flink}, is a new object which
generalizes {\em blackboard-framed link}. It plays an important role in this
work. I try to make the topological exposition as complete as possible: about
half of the exposition deals with the topological preliminaries. The objective
is to make it easier for the combinatorially oriented readers to understand the
paper. It is in the aegis of this work to find new important connections
between 3-manifolds and plane graphs.


title:
Security of high-dimensional quantum key distribution protocols using
  Franson interferometers

abstract:
  Franson interferometers are increasingly being proposed as a means of
securing high-dimensional energy-time entanglement-based quantum key
distribution (QKD) systems. Heuristic arguments have been proposed that purport
to demonstrate the security of these schemes. We show, however, that such
systems are vulnerable to attacks that localize the photons to several
temporally separate locations. This demonstrates that a single pair of Franson
interferometers is not a practical approach to securing high-dimensional
energy-time entanglement based QKD. This observations leads us to investigate
the security of modified Franson-based-protocols, where Alice and Bob have two
or more Franson interferometers. We show that such setups can improve the
sensitivity against attacks that localize the photons to multiple temporal
locations. While our results do not constituting a full security proof, they do
show that a single pair of Franson interferometers is not secure and that
multiple such interferometers could be a promising candidate for experimentally
realizable high-dimensional QKD.


title:
Zero-temperature limit of the Kawasaki dynamics for the Ising lattice
  gas in a large two-dimensional torus

abstract:
  We consider the Kawasaki dynamics at inverse temperature $\beta$ for the
Ising lattice gas on a two-dimensional square of length $2L+1$ with periodic
boundary conditions. We assume that initially the particles form a square of
length $n$, which may increase, as well as $L$, with $\beta$. We show that in a
proper time scale the particles form almost always a square and that the center
of mass of the square evolves as a Brownian motion when the temperature
vanishes.


title: Loop Quantum Corrections to Statefinder Parameters of Dark Energy

abstract:
  In this short letter, we presented the explicit forms of the statefinder
parameters for the Friedmann-Robertson-Walker (FRW) Universe in the loop
quantum cosmology (LQC) for Holographic dark energy and New-Agegraphic dark
energy. Numerically we investigated cosmological implications of these
parameters for models of dark energy.


title: Efficient Image Retargeting for High Dynamic Range Scenes

abstract:
  Most of the real world scenes have a very high dynamic range (HDR). The
mobile phone cameras and the digital cameras available in markets are limited
in their capability in both the range and spatial resolution. Same argument can
be posed about the limited dynamic range display devices which also differ in
the spatial resolution and aspect ratios.
  In this paper, we address the problem of displaying the high contrast low
dynamic range (LDR) image of a HDR scene in a display device which has
different spatial resolution compared to that of the capturing digital camera.
The optimal solution proposed in this work can be employed with any camera
which has the ability to shoot multiple differently exposed images of a scene.
Further, the proposed solutions provide the flexibility in the depiction of
entire contrast of the HDR scene as a LDR image with an user specified spatial
resolution. This task is achieved through an optimized content aware
retargeting framework which preserves salient features along with the algorithm
to combine multi-exposure images. We show the proposed approach performs
exceedingly well in the generation of high contrast LDR image of varying
spatial resolution compared to an alternate approach.


title: On Soft Mappings

abstract:
  In this paper, we introduce soft continuous mappings which are defined over
an initial universe set with a fixed set of parameters. Later we study soft
open and soft closed mappings, soft homeomorphism and investigate some
properties of these concepts.


title: Gr\"obner-Shirshov bases for some Lie algebras

abstract:
  We give Gr\"obner-Shirshov bases for Drinfeld-Kohno Lie algebra
$\textbf{L}_{n}$ in \cite{[Et]} and Kukin Lie algebra $A_P$ in \cite{Kukin},
where $P$ is a semigroup. As applications, we show that as $\mathbb{Z}$-module
$\textbf{L}_{n}$ is free and a $\mathbb{Z}$-basis of $\textbf{L}_{n}$ is given.
We give another proof of Kukin Theorem: if semigroup $P$ has the undecidable
word problem then the Lie algebra $A_P$ has the same property.


title: Normed \Omega-Group

abstract:
  Since sum which is not necessarily commutative is defined in \Omega-algebra
A, then \Omega-algebra A is called \Omega-group. I also considered
representation of \Omega-group. Norm defined in \Omega-group allows us to
consider continuity of operations and continuity of representation.


title: Distributed Learning of Distributions via Social Sampling

abstract:
  A protocol for distributed estimation of discrete distributions is proposed.
Each agent begins with a single sample from the distribution, and the goal is
to learn the empirical distribution of the samples. The protocol is based on a
simple message-passing model motivated by communication in social networks.
Agents sample a message randomly from their current estimates of the
distribution, resulting in a protocol with quantized messages. Using tools from
stochastic approximation, the algorithm is shown to converge almost surely.
Examples illustrate three regimes with different consensus phenomena.
Simulations demonstrate this convergence and give some insight into the effect
of network topology.


title: Minifolds and Phantoms

abstract:
  A minifold is a smooth projective $n$-dimensional variety such that its
bounded derived category of coherent sheaves $\D^b(X)$ admits a semi-orthogonal
decomposition into an exceptional collection of $n+1$ exceptional objects. In
this paper we classify minifolds of dimension $n \leq 4$. We conjecture that
the derived category of fake projective spaces have a similar semi-orthogonal
decomposition into a collection of $n+1$ exceptional objects and a category
with vanishing Hochschild homology. We prove this for fake projective planes
with non-abelian automorphism group. We construct new examples of phantom
categories with both Hochschild homology and Grothendieck group vanishing.


title: Universality of multiplicative infinite loop space machines

abstract:
  We establish a canonical and unique tensor product for commutative monoids
and groups in an infinity-category C which generalizes the ordinary tensor
product of abelian groups. Using this tensor product we show that
E_n-(semi)ring objects in C give rise to E_n-ring spectrum objects in C. In the
case that C is the infinity-category of spaces this produces a multiplicative
infinite loop space machine which can be applied to the algebraic K-theory of
rings and ring spectra.
  The main tool we use to establish these results is the theory of smashing
localizations of presentable infinity-categories. In particular, we identify
preadditive and additive infinity-categories as the local objects for certain
smashing localizations. A central theme is the stability of algebraic
structures under basechange; for example, we show Ring(D \otimes C) = Ring(D)
\otimes C. Lastly, we also consider these algebraic structures from the
perspective of Lawvere algebraic theories in infinity-categories.


title: "ATLAS Overview and Main Results"

abstract:
  An overview of the ATLAS experiment, its physics program and a selection of
the most important results, based on the data taken in pp collisions at
energies of 7 and 8 TeV in 2011 and 2012, respectively, is presented. The
question of possible changes in our understanding of elementary particles
physics, after a discovery of a new boson of the mass of ~125 GeV last summer,
is addressed. During the current long shutdown, the Large Hadron Collider (LHC)
will be upgraded to allow the LHC experiments to study pp collisions at the
energy of ~13 TeV.The ATLAS plans for future analyses and measurements with the
new data to be taken after 2015, are summarized.


title: Solution to the Proton Radius Problem

abstract:
  The relationship between the electric form factors for the proton in the rest
frame and in the Breit momentum frame is used to provide a value for the
difference in the mean squared charge radius of the proton evaluated in the two
frames. Associating the muonic-hydrogen data analysis for the proton charge
radius of 0.84087 fm with the rest frame and associating the electron
scattering with the Breit frame yields a prediction 0f 0.87944 fm for the
proton radius in the relativistic frame. The most recent value deduced via
electron scattering from the proton is 0.877(6)fm so that the frame dependence
used here yields a plausible solution to the proton radius puzzle.


title: Monomials as sum of k-th powers of forms

abstract:
  Motivated by recent results on the Waring problem for polynomial rings and
representation of monomial as sum of powers of linear forms, we consider the
problem of presenting monomials of degree kd as sums of k-th powers of forms of
degree d. We produce a general bound on the number of summands for any number
of variables which we refine in the two variables case. We completely solve the
k=3 case for monomials in two and three variables.


title: The large j limit for certain 9-j symbols-power law behaviour

abstract:
  In a previous work certain unitary9-j symbols were shown to go asymptotically
to zero in the large j limit. In this work we examine this inmore detail. We
find an approximate power law for the behaviour of ccertain U9-j's in the large
j limit and exponential decreased for others.


title:
Electronic Structure of LuRh2Si2: "Small" Fermi Surface Reference to
  YbRh2Si2

abstract:
  We present band structure calculations and quantum oscillation measurements
on LuRh2Si2, which is an ideal reference to the intensively studied quantum
critical heavy-fermion system YbRh2Si2. Our band structure calculations show a
strong sensitivity of the Fermi surface on the position of the silicon atoms
zSi within the unit cell. Single crystal structure refinement and comparison of
predicted and observed quantum oscillation frequencies and masses yield zSi =
0.379c in good agreement with numerical lattice relaxation. This value of zSi
is suggested for future band structure calculations on LuRh2Si2 and YbRh2Si2.
LuRh2Si2 with a full f electron shell represents the "small" Fermi surface
configuration of YbRh2Si2. Our experimentally and ab initio derived quantum
oscillation frequencies of LuRh2Si2 show strong differences with earlier
measurements on YbRh2Si2. Consequently, our results confirm the contribution of
the f electrons to the Fermi surface of YbRh2Si2 at high magnetic fields. Yet
the limited agreement with refined fully itinerant local density approximation
calculations highlights the need for more elaborated models to describe the
Fermi surface of YbRh2Si2.


title:
High-order harmonic generation from diatomic molecules in elliptically
  polarized driving fields: a generalized interference condition

abstract:
  We investigate the influence of intense, elliptically polarized driving
fields on high-order harmonic spectra from aligned diatomic molecules. We
derive a generalized two-center interference condition for elliptically
polarized fields, which accounts for s-p mixing and the orbital symmetry,
within the strong-field and the single-active electron approximation. We show
that the non-vanishing ellipticity introduces an effective dynamic shift in the
angle for which the two-center interference maxima and minima occur, with
regard to the existing condition for linearly polarized fields. This shift
depends on the ratio between the field-dressed momentum components of the
returning electron parallel and perpendicular to the major ellipticity axis
along each possible orbit. Because of this dependence, we find that there will
be a blurring in the two-center interference minima, and that increasing
ellipticity leads to splitting in such patterns. These features are
investigated in detail for H2 and Ar2.


title: $k$-Blocks: a connectivity invariant for graphs

abstract:
  A $k$-block in a graph $G$ is a maximal set of at least $k$ vertices no two
of which can be separated in $G$ by fewer than $k$ other vertices. The block
number $\beta(G)$ of $G$ is the largest integer $k$ such that $G$ has a
$k$-block.
  We investigate how $\beta$ interacts with density invariants of graphs, such
as their minimum or average degree. We further present algorithms that decide
whether a graph has a $k$-block, or which find all its $k$-blocks.
  The connectivity invariant $\beta(G)$ has a dual width invariant, the
block-width ${\rm bw}(G)$ of $G$. Our algorithms imply the duality theorem
$\beta = {\rm bw}$: a graph has a block-decomposition of width and adhesion $<
k$ if and only if it contains no $k$-block.


title:
Finite-horizon Online Transmission Rate and Power Adaptation on a
  Communication Link with Markovian Energy Harvesting

abstract:
  As energy harvesting communication systems emerge, there is a need for
transmission schemes that dynamically adapt to the energy harvesting process.
In this paper, after exhibiting a finite-horizon online throughput-maximizing
scheduling problem formulation and the structure of its optimal solution within
a dynamic programming formulation, a low complexity online scheduling policy is
proposed. The policy exploits the existence of thresholds for choosing rate and
power levels as a function of stored energy, harvest state and time until the
end of the horizon. The policy, which is based on computing an expected
threshold, performs close to optimal on a wide range of example energy harvest
patterns. Moreover, it achieves higher throughput values for a given delay,
than throughput-optimal online policies developed based on infinite-horizon
formulations in recent literature. The solution is extended to include ergodic
time-varying (fading) channels, and a corresponding low complexity policy is
proposed and evaluated for this case as well.


title: Capturing the Drunk Robber on a Graph

abstract:
  We show that the expected time for a smart "cop" to catch a drunk "robber" on
an $n$-vertex graph is at most $n + {\rm o}(n)$. More precisely, let $G$ be a
simple, connected, undirected graph with distinguished points $u$ and $v$ among
its $n$ vertices. A cop begins at $u$ and a robber at $v$; they move
alternately from vertex to adjacent vertex. The robber moves randomly,
according to a simple random walk on $G$; the cop sees all and moves as she
wishes, with the object of "capturing" the robber---that is, occupying the same
vertex---in least expected time. We show that the cop succeeds in expected time
no more than $n + {\rm o}(n)$. Since there are graphs in which capture time is
at least $n - o(n)$, this is roughly best possible. We note also that no
function of the diameter can be a bound on capture time.


title:
Reliability-based Error Detection for Feedback Communication with Low
  Latency

abstract:
  This paper presents a reliability-based decoding scheme for variable-length
coding with feedback and demonstrates via simulation that it can achieve higher
rates than Polyanskiy et al.'s random coding lower bound for variable-length
feedback (VLF) coding on both the BSC and AWGN channel. The proposed scheme
uses the reliability output Viterbi algorithm (ROVA) to compute the word error
probability after each decoding attempt, which is compared against a target
error threshold and used as a stopping criterion to terminate transmission. The
only feedback required is a single bit for each decoding attempt, informing the
transmitter whether the ROVA-computed word-error probability is sufficiently
low. Furthermore, the ROVA determines whether transmission/decoding may be
terminated without the need for a rate-reducing CRC.


title: Random crossings in dependency trees

abstract:
  It has been hypothesized that the rather small number of crossings in real
syntactic dependency trees is a side-effect of pressure for dependency length
minimization. Here we answer a related important research question: what would
be the expected number of crossings if the natural order of a sentence was lost
and replaced by a random ordering? We show that this number depends only on the
number of vertices of the dependency tree (the sentence length) and the second
moment about zero of vertex degrees. The expected number of crossings is
minimum for a star tree (crossings are impossible) and maximum for a linear
tree (the number of crossings is of the order of the square of the sequence
length).


title:
Effect of tensor force on density dependence of symmetry energy within
  the BHF Framework

abstract:
  The effect of tensor force on the density dependence of nuclear symmetry
energy has been investigated within the framework of the Brueckner-Hartree-Fock
approach. It is shown that the tensor force manifests its effect via the tensor
$^3SD_1$ channel. The density dependence of symmetry energy $E_{sym}$ turns out
to be determined essentially by the tensor force from the $\pi$ meson and
$\rho$ meson exchanges via the $^3SD_1$ coupled channel. Increasing the
strength of the tensor component due to the $\rho$-meson exchange tends to
enhance the repulsion of the equation of state of symmetric nuclear matter and
leads to reduction of symmetry energy. The present results confirm the dominant
role played by the tensor force in determining nuclear symmetry energy and its
density dependence within the microscopic BHF framework.


title: The Quantum Energy Density: Improved Efficiency for Quantum Monte Carlo

abstract:
  We establish a physically meaningful representation of a quantum energy
density for use in Quantum Monte Carlo calculations. The energy density
operator, defined in terms of Hamiltonian components and density operators,
returns the correct Hamiltonian when integrated over a volume containing a
cluster of particles. This property is demonstrated for a helium-neon "gas,"
showing that atomic energies obtained from the energy density correspond to
eigenvalues of isolated systems. The formation energies of defects or
interfaces are typically calculated as total energy differences. Using a model
of delta-doped silicon (where dopant atoms form a thin plane) we show how
interfacial energies can be calculated more efficiently with the energy
density, since the region of interest is small. We also demonstrate how the
energy density correctly transitions to the bulk limit away from the interface
where the correct energy is obtainable from a separate total energy
calculation.


title:
Multiwavelength Photometry and Hubble Space Telescope Spectroscopy of
  the Old Nova V842 Centaurus

abstract:
  We present ground-based optical and near infrared photometric observations
and Hubble Space Telescope COS spectroscopic observations of the old nova V842
Cen (Nova Cen 1986). Analysis of the optical light curves reveals a peak at
56.5 +/- 0.3s with an amplitude of 8.9 +/- 4.2 mma, which is consistent with
the rotation of a magnetic white dwarf primary in V842 Cen that was detected
earlier by Woudt et al., and led to its classification as an intermediate
polar.However, our UV lightcurve created from the COS time-tag spectra does not
show this periodicity. Our synthetic spectral analysis of an HST COS spectrum
rules out a hot white dwarf photosphere as the source of the FUV flux. The
best-fitting model to the COS spectrum is a full optically thick accretion disk
with no magnetic truncation, a low disk inclination angle, low accretion rate
and a distance less than half the published distance that was determined on the
basis of interstellar sodium D line strengths.Truncated accretion disks with
truncation radii of 3Rwd and 5Rwd yielded unsatisfactory agreement with the COS
data. The accretion rate is unexpectedly low for a classical nova only 24 years
after the explosion when the accretion rate is expected to be high and the
white dwarf should still be very hot, especially if irradiation of the donor
star took place. Our low accretion rate is consistent with low accretion rates
derived from X-ray and ground-based optical data.


title: Exceptional hyperbolic 3-manifolds

abstract:
  We correct and complete a conjecture of D. Gabai, R. Meyerhoff and N.
Thurston on the classification and properties of thin tubed closed hyperbolic
3-manifolds. We additionally show that if N is a closed hyperbolic 3-manifold,
then either N=Vol3 or N contains a closed geodesic that is the core of an
embedded tube of radius log(3)/2.


title: On Quantized Lienard Oscillator and Momentum Dependent Mass

abstract:
  We examine the analytical structure of the nonlinear Lienard oscillator and
show that it is a bi-Hamiltonian system depending upon the choice of the
coupling parameters. While one has been recently studied in the context of a
quantized momentum- dependent mass system, the other Hamiltonian also reflects
a similar feature in the mass function and also depicts an isotonic character.
We solve for such a Hamiltonian and give the complete solution in terms of a
confluent hypergeometric function.


title: On the classification of fifth-order integrable systems

abstract:
  In this work we classify the fifth-order integrable symmetrically coup led
systems of weight 0 that possess seventh-order symmetry. we obtained 2 new
integrable systems that related bi-Hamiltonian formulations are constructed
too.


title: Wave propagation in periodic lattices with defects of smaller dimension

abstract:
  The procedure of evaluating of the spectrum for discrete periodic operators
perturbed by operators of smaller dimensions is obtained. This result allows to
obtain propagative, guided, localised spectra for different kind of physical
operators on graphs with defects.


title:
Impact of the Nuclear Modification of the Gluon Densities on J/Psi
  production in pPb collisions at sqrt(s_NN) = 5 TeV

abstract:
  We update our previous studies of nuclear-matter effects on J/Psi production
in proton-nucleus for the recent LHC pPb runs at sqrt(s_NN)=5 TeV. We have
analysed the effects of the modification of the gluon PDFs in nucleus, using an
exact kinematics for a 2->2 process, namely g+g->J/Psi+g as expected from LO
pQCD. This allows to constrain the transverse-momentum while computing the
nuclear modification factor for different rapidities, unlike with the usual
simplified kinematics. Owing to the absence of measurement in pp collisions at
the same sqrt(s_NN) and owing to the expected significant uncertainties in
yield interpolations which would hinder definite interpretations of nuclear
modification factor --R_pPb--, we have derived forward-to-backward and
central-to-peripheral yield ratios in which the unknown proton-proton yield
cancel. These have been computed without and with a transverse-momentum cut,
e.g. to comply with the ATLAS and CMS constraints in the central-rapidity
region.


title: Blowing up and blurring finite Monk and rainbow algebras

abstract:
  We use Monk like algebras to give a new proof that the classes of strongly
representable relation algebras and finite dimensional cylindric algebras of
dimension >2 are not elementary. Our construction is based on relation algebras
have cylindric basis, so that we obtain the result for both in one go, since
they are both based on the same graph. The proof also uses Erdos' graphs. We
also show using a rainbow construction that the class SNr_n\CA_{n+k} is not
atom canonical, for any k\geq 4.


title: Optimal filtering and the dual process

abstract:
  We link optimal filtering for hidden Markov models to the notion of duality
for Markov processes. We show that when the signal is dual to a process that
has two components, one deterministic and one a pure death process, and with
respect to functions that define changes of measure conjugate to the emission
density, the filtering distributions evolve in the family of finite mixtures of
such measures and the filter can be computed at a cost that is polynomial in
the number of observations. Special cases of our framework include the Kalman
filter, and computable filters for the Cox-Ingersoll-Ross process and the
one-dimensional Wright-Fisher process, which have been investigated before. The
dual we obtain for the Cox-Ingersoll-Ross process appears to be new in the
literature.