title:
FeCr$_2$S$_4$ in magnetic fields: possible evidence for a multiferroic
  ground state

abstract:
  We report on neutron diffraction, thermal expansion, magnetostriction,
dielectric, and specific heat measurements on polycrystalline FeCr2S4 in
external magnetic fields. The ferrimagnetic ordering temperatures
$T_{\mathrm{C}}\approx 170$ K and the transition at $T_{\mathrm{OO}}\approx 10$
K, which has been associated with orbital ordering, are only weakly shifted in
magnetic fields up to 9 T. The cubic lattice parameter is found to decrease
when entering the state below $T_{\mathrm{OO}}$. The magnetic moments of the
Cr- and Fe-ions are reduced from the spin-only values throughout the
magnetically ordered regime, but approach the spin-only values for fields
$>$5.5 T. Thermal expansion in magnetic fields and magnetostriction experiments
indicate a contraction of the sample below about 60 K. Below $T_{\mathrm{OO}}$
this contraction is followed by a moderate expansion of the sample for fields
larger than $\sim$4.5 T. The transition at $T_{\mathrm{OO}}$ is accompanied by
an anomaly in the dielectric constant. The dielectric constant depends on both
the strength and orientation of the external magnetic field with respect to the
applied electric field for $T<T_{\mathrm{OO}}$. A linear correlation of the
magnetic-field-induced change of the dielectric constant and the magnetic-field
dependent magnetization is observed. This behaviour is consistent with the
existence of a ferroelectric polarization and a multiferroic ground state below
10 K.


title: A uniqueness theorem for higher order anharmonic oscillators

abstract:
  We study for $\alpha\in\R$, $k \in {\mathbb N} \setminus \{0\}$ the family of
self-adjoint operators \[
-\frac{d^2}{dt^2}+\Bigl(\frac{t^{k+1}}{k+1}-\alpha\Bigr)^2 \] in $L^2(\R)$ and
show that if $k$ is even then $\alpha=0$ gives the unique minimum of the lowest
eigenvalue of this family of operators. Combined with earlier results this
gives that for any $k \geq 1$, the lowest eigenvalue has a unique minimum as a
function of $\alpha$.


title: The magnetosphere of the close accreting PMS binary V4046 Sgr AB

abstract:
  We present a preliminary 3D potential field extrapolation model of the joint
magnetosphere of the close accreting PMS binary V4046 Sgr. The model is derived
from magnetic maps obtained as part of a coordinated optical and X-ray
observing program.


title:
Secure Layered Transmission in Multicast Systems with Wireless
  Information and Power Transfer

abstract:
  This paper considers downlink multicast transmit beamforming for secure
layered transmission systems with wireless simultaneous information and power
transfer. We study the power allocation algorithm design for minimizing the
total transmit power in the presence of passive eavesdroppers and energy
harvesting receivers. The algorithm design is formulated as a non-convex
optimization problem. Our problem formulation promotes the dual use of energy
signals in providing secure communication and facilitating efficient energy
transfer. Besides, we take into account a minimum required power for energy
harvesting at the idle receivers and heterogeneous quality of service (QoS)
requirements for the multicast video receivers. In light of the intractability
of the problem, we reformulate the considered problem by replacing a non-convex
probabilistic constraint with a convex deterministic constraint. Then, a
semidefinite programming relaxation (SDR) approach is adopted to obtain an
upper solution for the reformulated problem. Subsequently, sufficient
conditions for the global optimal solution of the reformulated problem are
revealed. Furthermore, we propose two suboptimal power allocation schemes based
on the upper bound solution. Simulation results demonstrate the excellent
performance and significant transmit power savings achieved by the proposed
schemes compared to isotropic energy signal generation.


title:
Optimal shapes of artificial bead-spring micro-carriers at low Reynolds
  numbers

abstract:
  Bead-based micro-swimmers are promising systems for payload delivery on the
micro-scale. However, the principles underlying their optimal design are not
yet fully understood. Here we study a simple device consisting of three
arbitrarily-shaped beads connected by two springs. We analytically determine
the most favorable kinematic parameters for sinusoidal driving, and show how
the swimmer changes from being a pusher to a puller. For cargo carrying
ellipsoidal beads, we perform geometric optimization under the constraint of a
constant total volume or surface area, with the aim of maximizing the device
transport velocity and efficiency. Interestingly, we identify two major
transport regimes, which arise from the competition between the elastic and the
drag forces faced by the swimmer. We construct a phase diagram that indicates
when the fastest swimming emerges because of minimized drag, and when due to
heightened interactions among the beads.


title:
A nonseparable amenable operator algebra which is not isomorphic to a
  C*-algebra

abstract:
  It has been a longstanding problem whether every amenable operator algebra is
isomorphic to a (necessarily nuclear) C*-algebra. In this note, we give a
nonseparable counterexample. The existence of a separable counterexample
remains an open problem. We also initiate a general study of unitarizability of
representations of amenable groups in C*-algebras and show that our method
cannot produce a separable counterexample.


title: Boulware-Deser ghost in extended quasidilaton massive gravity

abstract:
  In the extended quasidilaton massive gravity we perform a nonlinear
transformation of the shift vector and then calculate the second derivatives of
the Hamiltonian density with respect to the lapse function and the (nonlinearly
transformed) shift vector. It is then shown that the $4\times 4$ Hessian matrix
is invertible, meaning that the equations of motion for the lapse function and
the shift vector simply determine themselves. Therefore, there is no primary
constraint that removes the Boulware-Deser ghost.


title: Branching rules for quantum toroidal gl(n)

abstract:
  We construct an analog of the subalgebra $Ugl(n)\otimes Ugl(m)$ of $Ugl(m+n)$
in the setting of quantum toroidal algebras and study the restrictions of
various representations to this subalgebra.


title: Homogeneity and isotropy in a laboratory turbulent flow

abstract:
  We present a new design for a stirred tank that is forced by two parallel
planar arrays of randomly actuated synthetic jets. This arrangement creates
turbulence at high Reynolds number with low mean flow. Most importantly, it
exhibits a region of 3D homogeneous isotropic turbulence that is significantly
larger than the integral lengthscale. These features are essential for enabling
laboratory measurements of turbulent suspensions. We use quantitative imaging
to confirm isotropy at large, small, and intermediate scales by examining one--
and two--point statistics at the tank center. We then repeat these same
measurements to confirm that the values measured at the tank center are
constant over a large homogeneous region. In the direction normal to the
symmetry plane, our measurements demonstrate that the homogeneous region
extends for at least twice the integral length scale $L=9.5$ cm. In the
directions parallel to the symmetry plane, the region is at least four times
the integral lengthscale, and the extent in this direction is limited only by
the size of the tank. Within the homogeneous isotropic region, we measure a
turbulent kinetic energy of $6.07 \times 10^{-4} $m$^2$s$^{-2}$, a dissipation
rate of $4.65 \times 10^{-5} $m$^2$s$^{-3}$, and a Taylor--scale Reynolds
number of $R_\lambda=334$. The tank's large homogeneous region, combined with
its high Reynolds number and its very low mean flow, provides the best
approximation of homogeneous isotropic turbulence realized in a laboratory flow
to date. These characteristics make the stirred tank an optimal facility for
studying the fundamental dynamics of turbulence and turbulent suspensions.


title:
Measurement of light charged particles in the decay channels of
  medium-mass excited compound nuclei

abstract:
  The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on
the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy
spectra and multiplicities of the emitted light charged particles have been
compared to Monte Carlo simulations based on the statistical model. Indeed, in
this mass region (A about 100) models predict that shape transitions can occur
at high spin values and relatively scarce data exist in the literature about
coincidence measurements between evaporation residues and light charged
particles. Signals of shape transitions can be found in the variations of the
lineshape of high energy gamma rays emitted from the de-excitation of GDR
states gated on different region of angular momenta. For this purpose it is
important to keep under control the FE and FF processes, to regulate the
statistical model parameters and to control the onset of possible
preequilibrium emissions from 300 to 600 MeV bombarding energy.


title: A new proof of Bronshtein's theorem

abstract:
  We give a new self-contained proof of Bronshtein's theorem, that any
continuous root of a $C^{n-1,1}$-family of monic hyperbolic polynomials of
degree $n$ is locally Lipschitz, and obtain explicit bounds for the Lipschitz
constant of the root in terms of the coefficients. As a by-product we reprove
the recent result of Colombini, Orr\'u, and Pernazza, that a $C^n$-curve of
hyperbolic polynomials of degree $n$ admits a $C^1$-system of its roots.


title: Regularity of roots of polynomials

abstract:
  We show that smooth curves of monic complex polynomials $P_a
(Z)=Z^n+\sum_{j=1}^n a_j Z^{n-j}$, $a_j : I \to \mathbb C$ with $I \subset
\mathbb R$ a compact interval, have absolutely continuous roots in a uniform
way. More precisely, there exists a positive integer $k$ and a rational number
$p >1$, both depending only on the degree $n$, such that if $a_j \in C^{k}$
then any continuous choice of roots of $P_a$ is absolutely continuous with
derivatives in $L^q$ for all $1 \le q < p$, in a uniform way with respect to
$\max_j\|a_j\|_{C^k}$. The uniformity allows us to deduce also a multiparameter
version of this result. The proof is based on formulas for the roots of the
universal polynomial $P_a$ in terms of its coefficients $a_j$ which we derive
using resolution of singularities. For cubic polynomials we compute the
formulas as well as bounds for $k$ and $p$ explicitly.


title:
COSMOS A Context Sensitive Model For Dynamic Configuration Of
  Smartphones Using Multifactor Analysis

abstract:
  With the prolific growth in usage of smartphones across the spectrum of
people in the society it becomes mandatory to handle and configure these
devices effectively to achieve optimum results from it. This paper proposes a
context sensitive model termed COSMOS (COntext Sensitive MOdel for Smartphones)
for configuring the smartphones using multifactor analysis with the help of
decision trees. The COSMOS model proposed in this paper facilitates the
configuration of various smartphone settings implicitly based on the user's
current context, without interrupting the user for various inputs. The COSMOS
model also proposes multiple context parameters like location, scheduler data,
recent call log settings etc to decide the appropriate settings for the
smartphones. The proposed model is validated by a prototype implementation in
the Android platform. Various tests were conducted in the implementation and
the settings relevancy metric value of 90.95% confirms the efficiency of the
proposed model.


title:
Tests of hadronic vacuum polarization fits for the muon anomalous
  magnetic moment

abstract:
  Using experimental spectral data for hadronic tau decays from the OPAL
experiment, supplemented by a phenomenologically successful parameterization
for the high-s region not covered by the data, we construct a physically
constrained model of the isospin-one vector-channel polarization function.
Having such a model as a function of Euclidean momentum Q^2 allows us to
explore the systematic error associated with fits to the Q^2 dependence of
lattice data for the hadronic electromagnetic current polarization function
which have been used in attempts to compute the leading order hadronic
contribution, a_\mu^HLO, to the muon anomalous magnetic moment. In contrast to
recent claims made in the literature, we find that a final error in this
quantity of the order of a few percent does not appear possible with current
lattice data, given the present lack of precision in the determination of the
vacuum polarization at low Q^2. We also find that fits to the vacuum
polarization using fit functions based on Vector Meson Dominance are
unreliable, in that the fit error on a_\mu^HLO is typically much smaller than
the difference between the value obtained from the fit and the exact model
value. The use of a sequence of Pade approximants known to converge to the true
vacuum polarization appears to represent a more promising approach.


title:
Scaling of the largest dynamical barrier in the one-dimensional
  long-range Ising spin-glass

abstract:
  The long-range one-dimensional Ising spin-glass with random couplings
decaying as $J(r) \propto r^{-\sigma}$ presents a spin-glass phase
$T_c(\sigma)>0$ for $0 \leq \sigma<1$ (the limit $\sigma=0$ corresponds to the
mean-field SK-model). We use the eigenvalue method introduced in our previous
work [C. Monthus and T. Garel, J. Stat. Mech. P12017 (2009)] to measure the
equilibrium time $t_{eq}(N)$ at temperature $T=T_c(\sigma)/2$ as a function of
the number $N$ of spins. We find the activated scaling $\ln t_{eq}(N) \sim
N^{\psi}$ with the same barrier exponent $\psi \simeq 0.33$ in the whole region
$0\leq\sigma <1$.


title: Partition Functions and Stability Criteria of Topological Insulators

abstract:
  The non-chiral edge excitations of quantum spin Hall systems and topological
insulators are described by means of their partition function. The stability of
topological phases protected by time-reversal symmetry is rediscussed in this
context and put in relation with the existence of discrete anomalies and the
lack of modular invariance of the partition function. The $\Z_2$
characterization of stable topological insulators is extended to systems with
interacting and non-Abelian edge excitations.


title:
Determinant versus Permanent: salvation via generalization? The
  algebraic complexity of the Fermionant and the Immanant

abstract:
  The fermionant can be seen as a generalization of both the permanent (for
$k=-1$) and the determinant. We demonstrate that it is VNP-complete for most
cases. Furthermore it is #P-complete for the cases. The immanant is also a
generalization of the permanent (for a Young diagram with a single line) and of
the determinant (when the Young diagram is a column). We demonstrate that the
immanant of any family of Young diagrams with bounded width and at least n
boxes at the right of the first column is VNP-complete.


title:
The Gaia astrophysical parameters inference system (Apsis). Pre-launch
  description

abstract:
  The Gaia satellite will survey the entire celestial sphere down to 20th
magnitude, obtaining astrometry, photometry, and low resolution
spectrophotometry on one billion astronomical sources, plus radial velocities
for over one hundred million stars. Its main objective is to take a census of
the stellar content of our Galaxy, with the goal of revealing its formation and
evolution. Gaia's unique feature is the measurement of parallaxes and proper
motions with hitherto unparalleled accuracy for many objects. As a survey, the
physical properties of most of these objects are unknown. Here we describe the
data analysis system put together by the Gaia consortium to classify these
objects and to infer their astrophysical properties using the satellite's data.
This system covers single stars, (unresolved) binary stars, quasars, and
galaxies, all covering a wide parameter space. Multiple methods are used for
many types of stars, producing multiple results for the end user according to
different models and assumptions. Prior to its application to real Gaia data
the accuracy of these methods cannot be assessed definitively. But as an
example of the current performance, we can attain internal accuracies (RMS
residuals) on F,G,K,M dwarfs and giants at G=15 (V=15-17) for a wide range of
metallicites and interstellar extinctions of around 100K in effective
temperature (Teff), 0.1mag in extinction (A0), 0.2dex in metallicity ([Fe/H]),
and 0.25dex in surface gravity (logg). The accuracy is a strong function of the
parameters themselves, varying by a factor of more than two up or down over
this parameter range. After its launch in November 2013, Gaia will nominally
observe for five years, during which the system we describe will continue to
evolve in light of experience with the real data.


title:
The importance of non-photon noise in stellar spectropolarimetry. The
  spurious detection of a non-existing magnetic field in the A0 supergiant HD
  92207

abstract:
  The low-resolution, Cassegrain mounted, FORS spectropolarimeter of the ESO
Very Large Telescope is being extensively used for magnetic field surveys. Some
of the new discoveries suggest that relatively strong magnetic fields may play
an important role in numerous physical phenomena observed in the atmospheres as
well as in the circumstellar environments of certain kinds of stars. We show in
detail how small instabilities or data-reduction inaccuracies represent an
alternative explanation for the origin of certain signals of circular
polarisation published in recent years. With the help of analytical
calculations we simulate the observation of a spectral line in
spectropolarimetric mode, adding very small spurious wavelength shifts, which
may mimic the effects of seeing variations, rapid variations of the stellar
radial velocity, or instrument instabilities. As a case study, we then re-visit
the FORS2 measurements that have been used to claim the discovery of a magnetic
field in the A0 supergiant HD 92207. In addition, we present new observations
of this star obtained with the HARPSpol instrument. Both calibration and
science data show compelling evidence that photon-noise is not the only source
of error in magnetic field measurements, especially in sharp spectral lines.
Non-photon noise may be kept under control by accurate data reduction and
quality controls. Our re-analysis of FORS2 observations of HD 92207 shows no
evidence of a magnetic field, and we are able to reproduce the previous FORS
detection only by degrading the quality of our wavelength calibration. Our
HARPSpol spectropolarimetric measurements show no evidence of a magnetic field
at the level of 10 G.


title:
Rotation Periods, Variability Properties and Ages for Kepler Exoplanet
  Candidate Host Stars

abstract:
  We report rotation periods, variability characteristics, gyrochronological
ages for ~950 of the Kepler Object of Interest host stars. We find a wide
dispersion in the amplitude of the photometric variability as a function of
rotation, likely indicating differences in the spot distribution among stars.
We use these rotation periods in combination with published spectroscopic
measurements of vsini and stellar parameters to derive the stellar inclination
in the line-of-sight, and find a number of systems with possible spin-orbit
misalignment. We additionally find several systems with close-in planet
candidates whose stellar rotation periods are equal to or twice the planetary
orbital period, indicative of possible tidal interactions between these planets
and their parent stars. If these systems survive validation to become confirmed
planets, they will provide important clues to the evolutionary history of these
systems.


title: Rare $B_s$ decays in the relativistic quark model

abstract:
  The branchings fractions of the rare $B_s$ decays are calculated in the
framework of the QCD-motivated relativistic quark model. The form factors of
the weak $B_s$ transitions to light mesons are expressed through the overlap
integral of the initial and final meson wave functions in the whole accessible
kinematical range. Explicit determination of the momentum transfer dependence
of the form factors without additional model assumptions and extrapolations
significantly improve the reliability of the obtained results. The approximate
analytical form of the form factors is given in order to simplify the
comparison with other predictions and experiment. The calculated form factors
are applied for the investigations of the rare semileptonic, radiative and
nonleptonic $B_s$ decays. The factorization approximation is used for the
description of the nonleptonic decays. All results agree well with available
experimental data.


title: Four-Dimensional Asymptotically AdS Black Holes with Scalar Hair

abstract:
  We present a new family of asymptotically AdS four-dimensional black hole
solutions with scalar hair of a gravitating system consisting of a scalar field
minimally coupled to gravity with a self-interacting potential. For a certain
profile of the scalar field we solve the Einstein equations and we determine
the scalar potential. Thermodynamically we show that there is a critical
temperature below which there is a phase transition of a black hole with
hyperbolic horizon to the new hairy black hole configuration.


title: Maximal dissipation and well-posedness for the compressible Euler system

abstract:
  We discuss the problem of well-posedness of the compressible (barotropic)
Euler system in the framework of weak solutions. The principle of maximal
dissipation introduced by C.M. Dafermos is adapted and combined with the
concept of admissible weak solutions. We use the method of convex integration
in the spirit of the recent work of C.DeLellis and L.Szekelyhidi to show
various counterexamples to well-posedness. On the other hand, we conjecture
that the principle of maximal dissipation should be retained as a possible
criterion of uniqueness as it is violated by the oscillatory solutions obtained
in the process of convex integration.


title:
Regular Uniform Hypergraphs, $s$-Cycles, $s$-Paths and Their largest
  Laplacian H-Eigenvalues

abstract:
  In this paper, we show that the largest signless Laplacian H-eigenvalue of a
connected $k$-uniform hypergraph $G$, where $k \ge 3$, reaches its upper bound
$2\Delta(G)$, where $\Delta(G)$ is the largest degree of $G$, if and only if
$G$ is regular. Thus the largest Laplacian H-eigenvalue of $G$, reaches the
same upper bound, if and only if $G$ is regular and odd-bipartite. We show that
an $s$-cycle $G$, as a $k$-uniform hypergraph, where $1 \le s \le k-1$, is
regular if and only if there is a positive integer $q$ such that $k=q(k-s)$. We
show that an even-uniform $s$-path and an even-uniform non-regular $s$-cycle
are always odd-bipartite. We prove that a regular $s$-cycle $G$ with $k=q(k-s)$
is odd-bipartite if and only if $m$ is a multiple of $2^{t_0}$, where $m$ is
the number of edges in $G$, and $q = 2^{t_0}(2l_0+1)$ for some integers $t_0$
and $l_0$. We identify the value of the largest signless Laplacian H-eigenvalue
of an $s$-cycle $G$ in all possible cases. When $G$ is odd-bipartite, this is
also its largest Laplacian H-eigenvalue. We introduce supervertices for
hypergraphs, and show the components of a Laplacian H-eigenvector of an
odd-uniform hypergraph are equal if such components corresponds vertices in the
same supervertex, and the corresponding Laplacian H-eigenvalue is not equal to
the degree of the supervertex. Using this property, we show that the largest
Laplacian H-eigenvalue of an odd-uniform generalized loose $s$-cycle $G$ is
equal to $\Delta(G)=2$. We also show that the largest Laplacian H-eigenvalue of
a $k$-uniform tight $s$-cycle $G$ is not less than $\Delta(G)+1$, if the number
of vertices is even and $k=4l+3$ for some nonnegative integer $l$.


title: Sub-microsecond fast temporal evolution of the spin Seebeck effect

abstract:
  We present temporal evolution of the spin Seebeck effect in a YIG|Pt bilayer
system. Our findings reveal that this effect is a sub-microseconds fast
phenomenon governed by the temperature gradient and the thermal magnons
diffusion in the magnetic materials. A comparison of experimental results with
the thermal-driven magnon-diffusion model shows that the temporal behavior of
this effect depends on the time development of the temperature gradient in the
vicinity of the YIG|Pt interface. The effective thermal-magnon diffusion length
for YIG|Pt systems is estimated to be around 700nm.


title: The 42 reducts of the random ordered graph

abstract:
  The random ordered graph is the up to isomorphism unique countable
homogeneous linearly ordered graph that embeds all finite linearly ordered
graphs. We determine the reducts of the random ordered graph up to first-order
interdefinability.


title: Geometric Hamilton-Jacobi theory for higher-order autonomous systems

abstract:
  The geometric framework for the Hamilton-Jacobi theory is used to study this
theory in the ambient of higher-order mechanical systems, both in the
Lagrangian and Hamiltonian formalisms. Thus, we state the corresponding
Hamilton-Jacobi equations in these formalisms and apply our results to analyze
some particular physical examples.


title: Inverses of gamma functions

abstract:
  Euler's Gamma function $\Gamma$ either increases or decreases on intervals
between two consequtive critical points. The inverse of $\Gamma$ on intervals
of increase is shown to have an extension to a Pick-function and similar
results are given on the intervals of decrease, thereby answering a question by
Uchiyama. The corresponding integral representations are described. Similar
results are obtained for a class of entire functions of genus 2, and in
particular integral representations for the double gamma function and the
$G$-function of Barnes are found.


title: Large-scale optimization with the primal-dual column generation method

abstract:
  The primal-dual column generation method (PDCGM) is a general-purpose column
generation technique that relies on the primal-dual interior point method to
solve the restricted master problems. The use of this interior point method
variant allows to obtain suboptimal and well-centered dual solutions which
naturally stabilizes the column generation. As recently presented in the
literature, reductions in the number of calls to the oracle and in the CPU
times are typically observed when compared to the standard column generation,
which relies on extreme optimal dual solutions. However, these results are
based on relatively small problems obtained from linear relaxations of
combinatorial applications. In this paper, we investigate the behaviour of the
PDCGM in a broader context, namely when solving large-scale convex optimization
problems. We have selected applications that arise in important real-life
contexts such as data analysis (multiple kernel learning problem),
decision-making under uncertainty (two-stage stochastic programming problems)
and telecommunication and transportation networks (multicommodity network flow
problem). In the numerical experiments, we use publicly available benchmark
instances to compare the performance of the PDCGM against recent results for
different methods presented in the literature, which were the best available
results to date. The analysis of these results suggests that the PDCGM offers
an attractive alternative over specialized methods since it remains competitive
in terms of number of iterations and CPU times even for large-scale
optimization problems.


title: Xenon Reacts with Iron at the Conditions of the Earth's Core

abstract:
  Studies of the Earth's atmosphere have shown that more than 90% of xenon (Xe)
is depleted compared with its abundance in chondritic meteorites. This
long-standing missing Xe paradox has become the subject of considerable
interest and several models for a Xe reservoir have been proposed. Whether the
missing Xe is hiding in the Earth's core has remained a long unanswered
question. The key to address this issue lies in the reactivity of Xe with iron
(Fe, the main constituent of the Earth's core), which has been denied by
earlier studies. Here we report on the first evidence of the chemical reaction
of Xe and Fe at the conditions of the Earth's core, predicted through
first-principles calculations and unbiased structure searching techniques. We
find that Xe and Fe form a stable, inter-metallic compound of XeFe3, adopting a
Cu3Au-type face-centered cubic structure above 183 GPa and at 4470 K. As the
result of a Xe -> Fe charge transfer, Xe loses its chemical inertness by
opening up the filled 5p electron shell and functioning as a 5p-like element,
whilst Fe is unusually negatively charged, acting as an oxidant rather than a
reductant as usual. Our work establishes that the Earth's core is a natural
reservoir for Xe storage, and possibly provides the key to unlocking the
missing Xe paradox.


title: A multi-scale filament extraction method: getfilaments

abstract:
  Far-infrared imaging surveys of Galactic star-forming regions with Herschel
have shown that a substantial part of the cold interstellar medium appears as a
fascinating web of omnipresent filamentary structures. This highly anisotropic
ingredient of the interstellar material further complicates the difficult
problem of the systematic detection and measurement of dense cores in the
strongly variable but (relatively) isotropic backgrounds. Observational
evidence that stars form in dense filaments creates severe problems for
automated source extraction methods that must reliably distinguish sources not
only from fluctuating backgrounds and noise, but also from the filamentary
structures. A previous paper presented the multi-scale, multi-wavelength source
extraction method getsources based on a fine spatial scale decomposition and
filtering of irrelevant scales from images. In this paper, a multi-scale,
multi-wavelength filament extraction method getfilaments is presented that
solves this problem, substantially improving the robustness of source
extraction with getsources in filamentary backgrounds. The main difference is
that the filaments extracted by getfilaments are now subtracted by getsources
from detection images during source extraction, greatly reducing the chances of
contaminating catalogs with spurious sources. The intimate physical
relationship between forming stars and filaments seen in Herschel observations
demands that accurate filament extraction methods must remove the contribution
of sources and that accurate source extraction methods must be able to remove
underlying filamentary structures. Source extraction with getsources now
provides researchers also with clean images of filaments, free of sources,
noise, and isotropic backgrounds.


title: Quantitative stray field imaging of a magnetic vortex core

abstract:
  Thin-film ferromagnetic disks present a vortex spin structure whose dynamics,
added to the small size (~10 nm) of their core, earned them intensive study.
Here we use a scanning nitrogen-vacancy (NV) center microscope to
quantitatively map the stray magnetic field above a 1 micron-diameter disk of
permalloy, unambiguously revealing the vortex core. Analysis of both
probe-to-sample distance and tip motion effects through stroboscopic
measurements, allows us to compare directly our quantitative images to
micromagnetic simulations of an ideal structure. Slight perturbations with
respect to the perfect vortex structure are clearly detected either due to an
applied in-plane magnetic field or imperfections of the magnetic structures.
This work demonstrates the potential of scanning NV microscopy to map tiny
stray field variations from nanostructures, providing a nanoscale,
non-perturbative detection of their magnetic texture.


title: Average resistance of toroidal graphs

abstract:
  The average effective resistance of a graph is a relevant performance index
in many applications, including distributed estimation and control of network
systems. In this paper, we study how the average resistance depends on the
graph topology and specifically on the dimension of the graph. We concentrate
on $d$-dimensional toroidal grids and we exploit the connection between
resistance and Laplacian eigenvalues. Our analysis provides tight estimates of
the average resistance, which are key to study its asymptotic behavior when the
number of nodes grows to infinity. In dimension two, the average resistance
diverges: in this case, we are able to capture its rate of growth when the
sides of the grid grow at different rates. In higher dimensions, the average
resistance is bounded uniformly in the number of nodes: in this case, we
conjecture that its value is of order $1/d$ for large $d$. We prove this fact
for hypercubes and when the side lengths go to infinity.


title: On evolutionary games with periodic payoffs

abstract:
  Two cases of evolutionary stable strategy with periodic payoffs are studied.
The first is a generalization of Uyttendaele et al. The second is prisoner's
dilemma with periodic payoff. It is shown that reducing the defection payoff by
a periodic term is sufficient to introduce cooperation provided that the
initial fraction of cooperators is greater than 0.6.


title: On Separable Determination of Sigma-P-Porous Sets in Banach Spaces

abstract:
  We use a method involving elementary submodels and a partial converse of
Foran lemma to prove separable reduction theorems concerning Suslin
sigma-P-porous sets where "P" can be from a rather wide class of porosity-like
relations in complete metric spaces. In particular, we separably reduce the
notion of Suslin cone small set in Asplund spaces. As an application we prove a
theorem stating that a continuous approximately convex function on an Asplund
space is Frechet differentiable up to a cone small set.


title: Cascading failures in spatially-embedded random networks

abstract:
  Cascading failures constitute an important vulnerability of interconnected
systems. Here we focus on the study of such failures on networks in which the
connectivity of nodes is constrained by geographical distance. Specifically, we
use random geometric graphs as representative examples of such spatial
networks, and study the properties of cascading failures on them in the
presence of distributed flow. The key finding of this study is that the process
of cascading failures is non-self-averaging on spatial networks, and thus,
aggregate inferences made from analyzing an ensemble of such networks lead to
incorrect conclusions when applied to a single network, no matter how large the
network is. We demonstrate that this lack of self-averaging disappears with the
introduction of a small fraction of long-range links into the network. We
simulate the well studied preemptive node removal strategy for cascade
mitigation and show that it is largely ineffective in the case of spatial
networks. We introduce an altruistic strategy designed to limit the loss of
network nodes in the event of a cascade triggering failure and show that it
performs better than the preemptive strategy. Finally, we consider a real-world
spatial network viz. a European power transmission network and validate that
our findings from the study of random geometric graphs are also borne out by
simulations of cascading failures on the empirical network.


title: Non-galvanic primary thermometry of a two-dimensional electron gas

abstract:
  We report the experimental realization of a non-galvanic, primary thermometer
capable of measuring the electron temperature of a two-dimensional electron gas
with negligible thermal load. Such a thermometer consists of a quantum dot
whose temperature-dependent, single-electron transitions are detected by means
of a quantum-point-contact electrometer. Its operating principle is
demonstrated for a wide range of electron temperatures from 40 to 800 mK. This
noninvasive thermometry can find application in experiments addressing the
thermal properties of micrometer-scale mesoscopic electron systems, where
heating or cooling electrons requires relatively low thermal budgets.


title: Warp products and (2+1) dimensional spacetimes

abstract:
  We investigate the geometrical aspects of the extended (2+1) dimensional
Banados-Teitelboim-Zanelli spacetimes in the multiply warped product scheme. To
do this, we analyze the interior physical properties by constructing the
explicit warp functions in these regions.


title: On the Identifiability of the Functional Convolution Model

abstract:
  This report details conditions under which the Functional Convolution Model
described in \citet{AHG13} can be identified from Ordinary Least Squares
estimates without either dimension reduction or smoothing penalties. We
demonstrate that if the covariate functions are not spanned by the space of
solutions to linear differential equations, the functional coefficients in the
model are uniquely determined in the Sobolev space of functions with absolutely
continuous second derivatives.


title:
Current and voltage based bit errors and their combined mitigation for
  the Kirchhoff-law-Johnson-noise secure key exchange

abstract:
  We classify and analyze bit errors in the current measurement mode of the
Kirchhoff-law-Johnson-noise (KLJN) key distribution. The error probability
decays exponentially with increasing bit exchange period and fixed bandwidth,
which is similar to the error probability decay in the voltage measurement
mode. We also analyze the combination of voltage and current modes for error
removal. In this combination method, the error probability is still an
exponential function that decays with the duration of the bit exchange period,
but it has superior fidelity to the former schemes.


title: Self-protected polariton states in photonic quantum metamaterials

abstract:
  We investigate the single-photon transport properties of a one-dimensional
coupled cavity array (CCA) containing a single qubit in its central site by
coupling the CCA to two transmission lines supporting propagating bosonic modes
with linear dispersion. We find that even in the nominally weak light-matter
coupling regime, the transmission through a long array exhibits two
ultra-narrow resonances corresponding to long-lived self-protected polaritonic
states localized around the site containing the qubit. The lifetime of these
states is found to increase exponentially with the number of array sites in
sharp distinction to the polaritonic Bloch modes of the cavity array.


title: The status and future of EUV astronomy

abstract:
  The Extreme Ultraviolet wavelength range was one of the final windows to be
opened up to astronomy. Nevertheless, it provides very important diagnostic
tools for a range of astronomical objects, although the opacity of the
interstellar medium restricts the majority of observations to sources in our
own galaxy. This review gives a historical overview of EUV astronomy, describes
current instrumental capabilities and examines the prospects for future
facilities on small and medium-class satellite platforms.


title:
L1448-MM observations by the Herschel Key program, "Dust, Ice, and Gas
  In Time" (DIGIT)

abstract:
  We present Herschel/PACS observations of L1448-MM, a Class 0 protostar with a
prominent outflow. Numerous emission lines are detected at 55 < lambda < 210
micrometer including CO, OH, H2O, and [O I]. We investigate the spatial
distribution of each transition to find that lines from low energy levels tend
to distribute along the outflow direction while lines from high energy levels
peak at the central spatial pixel. Spatial maps reveal that OH emission lines
are formed in a relatively small area, while [O I] emission is extended.
According to the rotational diagram analysis, the CO emission can be fitted by
two (warm and hot) temperature components. For H2O, the ortho-to-para ratio is
close to 3. The non-LTE LVG calculations suggest that CO and H2O lines could
instead be formed in a high kinetic temperature (T > 1000 K) environment,
indicative of a shock origin. For OH, IR-pumping processes play an important
role in the level population. The molecular emission in L1448-MM is better
explained with a C-shock model, but the atomic emission of PACS [O I] and
Spitzer/IRS [Si II] emission is not consistent with C-shocks, suggesting
multiple shocks in this region. Water is the major line coolant of L1448-MM in
the PACS wavelength range, and the best-fit LVG models predict that H2O and CO
emit (50-80)% of their line luminosity in the PACS wavelength range.


title:
Application of Artificial Neural Networks in Estimating Participation in
  Elections

abstract:
  It is approved that artificial neural networks can be considerable effective
in anticipating and analyzing flows in which traditional methods and statics
are not able to solve. in this article, by using two-layer feedforward network
with tan-sigmoid transmission function in input and output layers, we can
anticipate participation rate of public in kohgiloye and boyerahmad province in
future presidential election of islamic republic of iran with 91% accuracy. the
assessment standards of participation such as confusion matrix and roc diagrams
have been approved our claims.


title:
Collective stochastic coherence and synchronizability in weighted
  scale-free networks

abstract:
  Coupling frequently enhances noise-induced coherence and synchronization in
interacting nonlinear systems, but it does so separately. In principle
collective stochastic coherence and synchronizability are incompatible
phenomena, since strongly synchronized elements behave identically and thus
their response to noise is indistinguishable to that of a single element.
Therefore one can expect systems that synchronize well to have a poor
collective response to noise. Here we show that, in spite of this apparent
conflict, a certain coupling architecture is able to reconcile the two
properties. Specifically, our results reveal that weighted scale-free networks
of diffusively coupled excitable elements exhibit both high synchronizability
of their subthreshold dynamics and a good collective response to noise of their
pulsed dynamics. This is established by comparing the behavior of this system
to that of random, regular, and unweighted scale-free networks. We attribute
the optimal response of weighted scale-free networks to the link homogeneity
(with respect to node degree) provided by the weighting procedure, which
balances the degree heterogeneity typical of SFNs.


title:
New proposal for non-linear ghost-free massive $F(R)$ gravity: cosmic
  acceleration and Hamiltonian analysis

abstract:
  We propose new version of massive $F(R)$ gravity which is natural
generalization of convenient massive ghost-free gravity. Its Hamiltonian
formulation in scalar-tensor frame is developed. We show that such $F(R)$
theory is ghost-free. The cosmological evolution of such theory is
investigated. Despite the strong Bianchi identity constraint the possibility of
cosmic acceleration (especially, in the presence of cold dark matter) is
established. Ghost-free massive $F(R,T)$ gravity is also proposed.


title:
A Solar Dynamo Model Driven by Mean-Field Alpha and Babcock-Leighton
  Sources: Fluctuations, Grand-Minima-Maxima and Hemispheric Asymmetry in
  Sunspot Cycles

abstract:
  Extreme solar activity fluctuations and the occurrence of solar grand minima
and maxima episodes, are well established, observed features of the solar
cycle. Nevertheless, such extreme activity fluctuations and the dynamics of the
solar cycle during Maunder minima-like episodes remain ill-understood. We
explore the origin of such extreme solar activity fluctuations and the role of
dual poloidal field sources, namely the Babcock-Leighton mechanism and the
mean-field alpha effect in the dynamics of the solar cycle. We mainly
concentrate on entry and recovery from grand minima episodes such as the
Maunder minimum and the dynamics of the solar cycle. We use a kinematic solar
dynamo model with a novel set-up in which stochastic perturbations force two
distinct poloidal field alpha effects. We explore different regimes of
operation of these poloidal sources with distinct operating thresholds, to
identify the importance of each. The perturbations are implemented
independently in both hemispheres which allows one to study the level of
hemispheric coupling and hemispheric asymmetry in the emergence of sunspots.
From the simulations performed we identify a few different ways in which the
dynamo can enter a grand minima episode. While fluctuations in any of the
$\alpha$ effects can trigger intermittency we find that the mean-field alpha
effect is crucial for the recovery of the solar cycle from a grand minima
episode which a Babcock-Leighton source alone, fails to achieve. Our
simulations also demonstrate other cycle dynamics. We conclude that stochastic
fluctuations in two interacting poloidal field sources working with distinct
operating thresholds is a viable candidate for triggering episodes of extreme
solar activity and that the mean-field alpha effect capable of working on weak,
sub-equipartition fields is critical to the recovery of the solar cycle
following an extended solar minimum.


title: Theory of intersecting loops on a torus

abstract:
  We continue our investigation into intersections of closed paths on a torus,
to further our understanding of the commutator algebra of Wilson loop
observables in 2+1 quantum gravity, when the cosmological constant is negative.
We give a concise review of previous results, e.g. that signed area phases
relate observables assigned to homotopic loops, and present new developments in
this theory of intersecting loops on a torus. We state precise rules to be
applied at intersections of both straight and crooked/rerouted paths in the
covering space $\mathbb{R}^2$. Two concrete examples of combinations of
different rules are presented.


title: IR Spectrometer Project for the BTA Telescope

abstract:
  We introduce a project of new cooled infrared spectrometer-photometer for 6-m
telescope BTA (Special Astrophysical Observatory of Russian Science Academy).
The device would extend the wavelength range accessible for observations on the
6-m BTA telescope toward near infrared (0.8-2.5 um).


title: On R\'enyi entropies of disjoint intervals in conformal field theory

abstract:
  We study the R\'enyi entropies of N disjoint intervals in the conformal field
theories given by the free compactified boson and the Ising model. They are
computed as the 2N point function of twist fields, by employing the partition
function of the model on a particular class of Riemann surfaces. The results
are written in terms of Riemann theta functions. The prediction for the free
boson in the decompactification regime is checked against exact results for the
harmonic chain. For the Ising model, matrix product states computations agree
with the conformal field theory result once the finite size corrections have
been taken into account.


title: Existence of 'Darboux chart' on loop space

abstract:
  For a finite dimensional symplectic manifold $(M,\omega)$ with a symplectic
form $\omega$, corresponding loop space ($LM=C^\infty(S^1,M)$) admits a weak
symplectic form $\Omega^\omega$. We prove that the loop space over $\mbr^n$
admits Darboux chart for the weak symplectic structure $\Omega^\omega$.
Further, we show that inclusion map from the symplectic cohomology (as defined
by Kriegl and Michor \cite{KM}) of the loop space over $\mathbb R^n$ to the De
Rham cohomology of the loop space is an isomorphism.


title: The Cardinality of Sumsets: Different Summands

abstract:
  Let $h$ be a positive integer and $A, B_1, B_2,\dots, B_h$ be finite sets in
a commutative group. We bound $|A+B_1+...+B_h|$ from above in terms of $|A|,
|A+B_1|,\dots,|A+B_h|$ and $h$. Extremal examples, which demonstrate that the
bound is asymptotically sharp in all the parameters, are furthermore provided.


title:
Quantum charge pumping in graphene-based devices: When lattice defects
  do help

abstract:
  Quantum charge pumping, the quantum coherent generation of a dc current at
zero bias through time dependent potentials, provides outstanding opportunities
for metrology and the development of new devices. The long electronic coherence
times and high quality of the crystal structure of graphene may provide
suitable building blocks for such quantum pumps. Here, we focus in adiabatic
quantum pumping through graphene nanoribbons in the Fabry-P\'{e}rot regime
highlighting the crucial role of defects by using atomistic simulations. We
show that even a single defect added to the pristine structure may produce a
two orders of magnitude increase in the pumped charge.


title:
Inertial-sensor bias estimation from brightness/depth images and based
  on SO(3)-invariant integro/partial-differential equations on the unit sphere

abstract:
  Constant biases associated to measured linear and angular velocities of a
moving object can be estimated from measurements of a static scene by embedded
brightness and depth sensors. We propose here a Lyapunov-based observer taking
advantage of the SO(3)-invariance of the partial differential equations
satisfied by the measured brightness and depth fields. The resulting asymptotic
observer is governed by a non-linear integro/partial differential system where
the two independent scalar variables indexing the pixels live on the unit
sphere of the 3D Euclidian space. The observer design and analysis are strongly
simplified by coordinate-free differential calculus on the unit sphere equipped
with its natural Riemannian structure. The observer convergence is investigated
under C^1 regularity assumptions on the object motion and its scene. It relies
on Ascoli-Arzela theorem and pre-compactness of the observer trajectories. It
is proved that the estimated biases converge towards the true ones, if and only
if, the scene admits no cylindrical symmetry. The observer design can be
adapted to realistic sensors where brightness and depth data are only available
on a subset of the unit sphere. Preliminary simulations with synthetic
brightness and depth images (corrupted by noise around 10%) indicate that such
Lyapunov-based observers should be robust and convergent for much weaker
regularity assumptions.


title: Small particle limits in a regularized Laplacian random growth model

abstract:
  We study a regularized version of Hastings-Levitov planar random growth that
models clusters formed by the aggregation of diffusing particles. In this
model, the growing clusters are defined in terms of iterated slit maps whose
capacities are given by c_n=c|\Phi_{n-1}'(e^{\sigma+i\theta_n})|^{-\alpha},
\alpha \geq 0, where c>0 is the capacity of the first particle, {\Phi_n}_n are
the composed conformal maps defining the clusters of the evolution,
{\theta_n}_n are independent uniform angles determining the positions at which
particles are attached, and \sigma>0 is a regularization parameter which we
take to depend on c. We prove that under an appropriate rescaling of time, in
the limit as c converges to 0, the clusters converge to growing disks with
deterministic capacities, provided that \sigma does not converge to 0 too fast.
We then establish scaling limits for the harmonic measure flow, showing that by
letting \alpha tend to 0 at different rates it converges to either the Brownian
web on the circle, a stopped version of the Brownian web on the circle, or the
identity map. As the harmonic measure flow is closely related to the internal
branching structure within the cluster, the above three cases intuitively
correspond to the number of infinite branches in the model being either 1, a
random number whose distribution we obtain, or unbounded, in the limit as c
converges to 0.
  We also present several findings based on simulations of the model with
parameter choices not covered by our rigorous analysis.


title: A new pentagon identity for the tetrahedron index

abstract:
  Recently Kashaev, Luo and Vartanov, using the reduction from a
four-dimensional superconformal index to a three-dimensional partition
function, found a pentagon identity for a special combination of hyperbolic
Gamma functions. Following their idea we have obtained a new pentagon identity
for a certain combination of so-called tetrahedron indices arising from the
equality of superconformal indices of dual three-dimensional N=2 supersymmetric
theories and give a mathematical proof of it.


title: New insights in \bar{K}N scattering and the \Lambda(1405)

abstract:
  We discuss in this talk aspects of \bar{K}N plus coupled channels dynamics
with special emphasis on the \Lambda(1405) resonance and isovector resonances
in the same energy region. We comment on several experimental reactions giving
rise to \pi\Sigma distributions with important implications on the
spectroscopy. We also discuss recent theoretical models based con NLO SU(3)
unitarized chiral perturbation theory.


title: A d-shifted Darboux theorem

abstract:
  We give a local model for d-shifted symplectic dg-schemes, or Deligne-Mumford
dg-stacks [PTVV]. Locally any such is a product of a "twisted shifted cotangent
bundle", where the twist is given by an element df, with $f \in H^{1-d}(\Cal
O)$, and a quadratic bundle in middle degree. The latter only occurs if d =
4r+2.


title: Understanding tetrahedral liquids through patchy colloids

abstract:
  We investigate the structural properties of a simple model for tetrahedral
patchy colloids in which the patch width and the patch range can be tuned
independently. For wide bond angles, a fully bonded network can be generated by
standard Monte Carlo or molecular dynamics simulations of the model, providing
a neat method for generating defect-free random tetrahedral networks. This
offers the possibility of focusing on the role of the patch angular width on
the structure of the fully bonded network. The analysis of the fully bonded
configurations as a function of the bonding angle shows how the bonding angle
controls the system compressibility, the strength of the pre-peak in the
structure factor and ring size distribution. Comparison with models of liquid
water and silica allows us to find the best mapping between these continuous
potentials and the colloidal one. Building on previous studies focused on the
connection between angular range and crystallization, the mapping makes it
possible to shed new light on the glass-forming ability of network-forming
tetrahedral liquids.


title:
Distinguishing Topical and Social Groups Based on Common Identity and
  Bond Theory

abstract:
  Social groups play a crucial role in social media platforms because they form
the basis for user participation and engagement. Groups are created explicitly
by members of the community, but also form organically as members interact. Due
to their importance, they have been studied widely (e.g., community detection,
evolution, activity, etc.). One of the key questions for understanding how such
groups evolve is whether there are different types of groups and how they
differ. In Sociology, theories have been proposed to help explain how such
groups form. In particular, the common identity and common bond theory states
that people join groups based on identity (i.e., interest in the topics
discussed) or bond attachment (i.e., social relationships). The theory has been
applied qualitatively to small groups to classify them as either topical or
social. We use the identity and bond theory to define a set of features to
classify groups into those two categories. Using a dataset from Flickr, we
extract user-defined groups and automatically-detected groups, obtained from a
community detection algorithm. We discuss the process of manual labeling of
groups into social or topical and present results of predicting the group label
based on the defined features. We directly validate the predictions of the
theory showing that the metrics are able to forecast the group type with high
accuracy. In addition, we present a comparison between declared and detected
groups along topicality and sociality dimensions.


title: Minimum vertex degree threshold for $C_4^3$-tiling

abstract:
  We prove that the vertex degree threshold for tiling $\C_4^3$ (the 3-uniform
hypergraph with four vertices and two triples) in a 3-uniform hypergraph on
$n\in 4\mathbb N$ vertices is $\binom{n-1}2 - \binom{\frac34 n}2+\frac38n+c$,
where $c=1$ if $n\in 8\mathbb N$ and $c=-\frac12$ otherwise. This result is
best possible, and is one of the first results on vertex degree conditions for
hypergraph tiling.


title: G-parking functions and tree inversions

abstract:
  A depth-first search version of Dhar's burning algorithm is used to give a
bijection between the parking functions of a graph and labeled spanning trees,
relating the degree of the parking function with the number of inversions of
the spanning tree. Specializing to the complete graph answers a problem posed
by R. Stanley.


title: Thermal Correction to the Molar Polarizability of a Boltzmann Gas

abstract:
  Metrology in atomic physics has been crucial for a number of advanced
determinations of fundamental constants. In addition to very precise frequency
measurements, the molar polarizability of an atomic gas has recently also been
measured very accurately. Part of the motivation for the measurements is due to
ongoing efforts to redefine the International System of Units (SI) for which an
accurate value of the Boltzmann constant is needed. Here, we calculate the
dominant shift of the molar polarizability in an atomic gas due to thermal
effects. It is given by the relativistic correction to the dipole interaction,
which emerges when the probing electric field is Lorenz transformed into the
rest frame of the atoms that undergo thermal motion. While this effect is small
when compared to currently available experimental accuracy, the relativistic
correction to the dipole interaction is much larger than the thermal shift of
the polarizability induced by blackbody radiation.


title:
Newly observed $D_J(3000)^{+,0}$ and $D_J^*(3000)^0$ as $2P$ states in
  $D$ meson family

abstract:
  In this work, we study the newly observed $D_J(3000)$ and $D_J^*(3000)$
through the analysis of mass spectrum and calculation of the corresponding
two-body strong decay behaviors. Our results show that $D_J(3000)$ and
$D_J^*(3000)$ are explained as the $2P(1^+)$ and $2^3P_0$ states in the $D$
meson family, respectively, which is supported by the calculated masses of
these two states and their decay behaviors. As a byproduct, the decay behaviors
of $3^1S_0$, $3^3S_1$, $2D(2^-)$, $2^3D_1$, $2D^\prime(2^-)$, $2^3D_3$,
$2P^\prime(1^+)$, $2^3P_2$, $1F(3^+)$, $1^3F_2$, $1F^\prime(3^+)$, and $1^3F_4$
states are also given, which will be helpful to further experimentally study
mixings of these $D$ mesons, too.


title:
Competition between the s-wave and p-wave superconductivity phases in a
  holographic model

abstract:
  We build a holographic superconductor model with a scalar triplet charged
under an SU(2) gauge field in the bulk. In this model, the s-wave and p-wave
condensates can be consistently realized. We find that there are totally four
phases in this model, namely, the normal phase without any condensate, s-wave
phase, p-wave phase and the s+p coexisting phase. By calculating Gibbs free
energy, the s+p coexisting phase turns out to be thermodynamically favored once
it can appear. The phase diagram with the dimension of the scalar operator and
temperature is drawn. The temperature range for the s+p coexisting phase is
very narrow, which shows the competition between the s-wave and p-wave orders
in the superconductor model.


title: A Note on Strongly Quasidiagonal Groups

abstract:
  In this note we address a question of Don Hadwin: "Which groups have strongly
quasidiagonal C*-algebras?" In recent work we showed that all finitely
generated virtually nilpotent groups have strongly quasidiagonal C*-algebras,
while together with Carri\'on and Dadarlat we showed that most wreath products
fail to have strongly quasidiagonal C*-algebras. These two results raised the
question of whether or not strong quasidiagonality could characterize virtual
nilpotence among finitely generated groups. The purpose of this note is to
provide examples of finitely generated groups (in fact of the form $\Z^3\rtimes
\Z^2$) that are not virtually nilpotent yet have strongly quasidiagonal
C*-algebras. Moreover we show these examples are the "simplest" possible by
proving that a group of the form $\Z^d\rtimes \Z$ is virtually nilpotent if and
only if its group C*-algebra is strongly quasidiagonal.


title:
Clues to the Formation of Lenticular Galaxies Using Spectroscopic
  Bulge-Disk Decomposition

abstract:
  Lenticular galaxies have long been thought of as evolved spirals, but the
processes involved to quench the star formation are still unclear. By studying
the individual star formation histories of the bulges and disks of lenticulars,
it is possible to look for clues to the processes that triggered their
transformation from spirals. To accomplish this feat, we present a new method
for spectroscopic bulge-disk decomposition, in which a long-slit spectrum is
decomposed into two one-dimensional spectra representing purely the bulge and
disk light. We present preliminary results from applying this method to
lenticular galaxies in the Virgo and Fornax Clusters, in which we show that the
most recent star formation activity in these galaxies occurred within the
bulges. We also find that the bulges are in general more Fe-enriched than the
disks of the same galaxy, and that this enrichment grows stronger as the age of
the bulge becomes younger. These results point towards a scenario where the
star formation in the disks of spiral galaxies are quenched, followed by a
burst of star formation in the central regions from the gas that has been
funnelled inwards through the disk.


title:
Asteroseismic Signatures of Magnetic Activity Variations in Solar-type
  Stars

abstract:
  Observations of magnetic activity cycles in other stars provide a broader
context for our understanding of the 11-year sunspot cycle. The discovery of
short activity cycles in a few stars, and the recognition of analogous
variability in the Sun, suggest that there may be two distinct dynamos
operating in different regions of the interior. Consequently, there is a
natural link between studies of magnetic activity and asteroseismology, which
can characterize some of the internal properties that are relevant to dynamos.
I provide a brief historical overview of the connection between these two
fields (including prescient work by Wojtek Dziembowski in 2007), and I
highlight some exciting results that are beginning to emerge from the Kepler
mission.


title:
A Novel Methodology to Overcome Routing Misbehavior in MANET using
  Retaliation Model

abstract:
  MANET is a cooperative network in which nodes are responsible for forwarding
as well as routing. Noncooperation is still a big challenge that certainly
degrades the performance and reliability of a MANET. This paper presents a
novel methodology to overcome routing misbehavior in MANET using Retaliation
Model. In this model node misbehavior is watched and an equivalent misbehavior
is given in return. This model employs several parameters such as number of
packets forwarded, number of packets received for forwarding, packet forwarding
ratio etc. to calculate Grade and Bonus Points. The Grade is used to isolate
selfish nodes from the routing paths and the Bonus Points defines the number of
packets dropped by an honest node in retaliation over its misconducts. The
implementation is done in "GloMoSim" on top of the DSR protocol. We obtained up
to 40% packet delivery ratio with a cost of a minimum of 7.5% overhead compared
to DSR. To minimize total control traffic overhead we have included the FG
Model with our model and it reduces the overhead up to 75%. This model enforces
cooperation due to its stricter punishment strategy and justifies its name.


title:
The resurgence properties of the large order asymptotics of the Hankel
  and Bessel functions

abstract:
  The aim of this paper is to derive new representations for the Hankel and
Bessel functions, exploiting the reformulation of the method of steepest
descents by M. V. Berry and C. J. Howls (Berry and Howls, Proc. R. Soc. Lond. A
434 (1991) 657--675). Using these representations, we obtain a number of
properties of the large order asymptotic expansions of the Hankel and Bessel
functions due to Debye, including explicit and realistic error bounds,
asymptotics for the late coefficients, exponentially improved asymptotic
expansions, and the smooth transition of the Stokes discontinuities.


title:
The Interaction of Two Coronal Mass Ejections: Influence of Relative
  Orientation

abstract:
  We report on a numerical investigation of two coronal mass ejections (CMEs)
which interact as they propagate in the inner heliosphere. We focus on the
effect of the orientation of the CMEs relative to each other by performing four
different simulations with the axis of the second CME rotated by 90 degrees
from one simulation to the next. Each magneto-hydrodynamic (MHD) simulation is
performed in three dimensions (3-D) with the Space Weather Modeling Framework
(SWMF) in an idealized setting reminiscent of solar minimum conditions. We
extract synthetic satellite measurements during and after the interaction and
compare the different cases. We also analyze the kinematics of the two CMEs,
including the evolution of their widths and aspect ratios. We find that the
first CME contracts radially as a result of the interaction in all cases, but
the amount of subsequent radial expansion depends on the relative orientation
of the two CMEs. Reconnection between the two ejecta and between the ejecta and
the interplanetary magnetic field (IMF) determines the type of structure
resulting from the interaction. When a CME with a high inclination with respect
to the ecliptic overtakes one with a low inclination, it is possible to create
a compound event with a smooth rotation in the magnetic field vector over more
than 180 degrees. Due to reconnection, the second CME only appears as an
extended "tail", and the event may be mistaken for a glancing encounter with an
isolated CME. This configuration differs significantly from the one usually
studied of a multiple-magnetic cloud event, which we found to be associated
with the interaction of two CMEs with the same orientation.


title: Hedging in a market with jumps - an FBSDE approach

abstract:
  We propose a model for hedging in a market with jumps for a large investor.
The dynamics of the stock prices and the value process is governed by
forward-backward SDEs driven by Teugels martingales. Unlike known FBSDE market
models, ours accounts for jumps in stock prices. Moreover, it allows to find an
optimal hedging strategy.


title: The Manickam-Mikl\'os-Singhi Conjectures for Sets and Vector Spaces

abstract:
  More than twenty-five years ago, Manickam, Mikl\'{o}s, and Singhi conjectured
that for positive integers $n,k$ with $n \geq 4k$, every set of $n$ real
numbers with nonnegative sum has at least $\binom{n-1}{k-1}$ $k$-element
subsets whose sum is also nonnegative. We verify this conjecture when $n \geq
8k^{2}$, which simultaneously improves and simplifies a bound of Alon, Huang,
and Sudakov and also a bound of Pokrovskiy when $k < 10^{45}$.
  Moreover, our arguments resolve the vector space analogue of this conjecture.
Let $V$ be an $n$-dimensional vector space over a finite field. Assign a
real-valued weight to each $1$-dimensional subspace in $V$ so that the sum of
all weights is zero. Define the weight of a subspace $S \subset V$ to be the
sum of the weights of all the $1$-dimensional subspaces it contains. We prove
that if $n \geq 3k$, then the number of $k$-dimensional subspaces in $V$ with
nonnegative weight is at least the number of $k$-dimensional subspaces in $V$
that contain a fixed $1$-dimensional subspace. This result verifies a
conjecture of Manickam and Singhi from 1988.


title:
Induced magneto-transport properties at palladium/yttrium iron garnet
  interface

abstract:
  As a thin layer of palladium (Pd) is directly deposited on an yttrium iron
garnet or YIG (Y3Fe5O12) magnetic insulator film, Pd develops both low- and
high-field magneto-transport effects that are absent in standalone Pd or thick
Pd on YIG. While the low-field magnetoresistance peak of Pd tracks the coercive
field of the YIG film, the much larger high-field magnetoresistance and the
Hall effect do not show any obvious relationship with the bulk YIG
magnetization. The distinct high-field magneto-transport effects in Pd are
shown to be caused by interfacial local moments in Pd.


title: All optical Amplification in Metallic Subwavelength Linear Waveguides

abstract:
  Proposed all optical amplification scenario is based on the properties of
light propagation in two coupled subwavelength metallic slab waveguides where
for particular choice of waveguide parameters two propagating (symmetric) and
non-propagating (antisymmetric) eigenmodes coexist. For such a setup incident
beams realize boundary conditions for forming a stationary state as a
superposition of mentioned eigenmodes. It is shown both analytically and
numerically that amplification rate in this completely linear mechanism
diverges for small signal values.


title: Optimality of Gaussian Discord

abstract:
  In this Letter we exploit the recently-solved conjecture on the bosonic
minimum output entropy to show the optimality of Gaussian discord, so that the
computation of quantum discord for bipartite Gaussian states can be restricted
to local Gaussian measurements. We prove such optimality for a large family of
Gaussian states, including all two-mode squeezed thermal states, which are the
most typical Gaussian states realized in experiments. Our family also includes
other types of Gaussian states and spans their entire set in a suitable limit
where they become Choi-matrices of Gaussian channels. As a result, we
completely characterize the quantum correlations possessed by some of the most
important bosonic states in quantum optics and quantum information.

categories: quant-ph cond-mat.stat-mech math-ph math.MP physics.optics


title: The classification of \tau-tilting modules over Nakayama algebras

abstract:
  In this paper, we study tau-tilting modules over Nakayama algebras. We
establish bijections between tau-tilting modules, triangulations of a polygon
with a puncture and certain integer sequences. Moreover, we give an algorithm
to construct the Hasse quiver of support tau-tilting modules by using Rejection
Lemma of Drozd-Kirichenko.


title:
Scaling of genuine multiparticle entanglement at a quantum phase
  transition

abstract:
  We investigate the scaling and spatial distribution of genuine multiparticle
entanglement in three- and four-spin reduced states of the one-dimensional
XY-model at the quantum phase transition. We observe a logarithmic divergence
and show that genuine three- and four-particle entanglement obeys finite-size
scaling.


title:
Relaxation for an optimal design problem with linear growth and
  perimeter penalization

abstract:
  The paper is devoted to the relaxation and integral representation in the
space of functions of bounded variation for an integral energy arising from
optimal design problems. The presence of a perimeter penalization is also
considered in order to avoid non existence of admissible solutions, besides
this leads to an interaction in the limit energy. Also more general models have
been taken into account.


title:
Classical and quantum capacities of a fully correlated amplitude damping
  channel

abstract:
  We study information transmission over a fully correlated amplitude damping
channel acting on two qubits. We derive the single-shot classical channel
capacity and show that entanglement is needed to achieve the channel best
performance. We discuss the degradability properties of the channel and
evaluate the quantum capacity for any value of the noise parameter. We finally
compute the entanglement-assisted classical channel capacity.


title:
Modelling the spatial shape of nondiffracting beams: Experimental
  generation of Frozen Waves via computer generated holograms

abstract:
  In this paper we implement experimentally the spatial shape modelling of
nondiffracting optical beams via computer generated holograms. The results
reported here are the experimental confirmation of the so called Frozen Wave
method, developed few years ago. Optical beams of this type can possess
potential applications in optical tweezers, medicine, atom guiding, remote
sensing, etc..


title: M00N states in ion-laser interactions

abstract:
  A new class of entangled states, similar to N00N states is introduced. We
call these states M00N states as the excitations shared in both subsystems do
not need to be equal. The generation proposed here does not need conditional
measurements, and therefore is achieved in a deterministic manner.


title: Dynamics of a vertical water bridge

abstract:
  A vertical connection of water is formed when a high voltage electrode is
dipped in and pulled out of a container of deionized water. We considered the
formation and dynamical characteristics of this vertical water bridge. For the
first time in this field, instabilities were observed in the bridge that led to
an oscillatory behaviour which we categorized them into three dynamical
regimes. some explanations were supplied on the physics behind these dynamics.
We report the formation of macroscopic droplets during our experiments, which
their dynamics revealed that they are electrically charged. In some cases the
droplets levitated in the air due to the equality of gravity and electrical
force (acting in the opposite direction). Our results shed light on the physics
behind this phenomenon and the horizontal water bridge, which explanations
regarding its underlying physics have led to controversial theories and
discussions before.


title: Dark energy in thermal equilibrium with the cosmological horizon?

abstract:
  According to a generalization of black hole thermodynamics to a cosmological
framework, it is possible to define a temperature for the cosmological horizon.
The hypothesis of thermal equilibrium between the dark energy and the horizon
has been considered by many authors. We find the restrictions imposed by this
hypothesis on the energy transfer rate ($Q_i$) between the cosmological fluids,
assuming that the temperature of the horizon have the form $T=b/2\pi R$, where
$R$ is the radius of the horizon. We more specifically consider two types of
dark energy: holographic dark energy (HDE) and dark energy with a constant EoS
parameter ($w$DE). In each case, we show that for a given radius $R$, there is
an unique term $Q_{de}$ that is consistent with thermal equilibrium. We also
consider the situation where, in addition to dark energy, other fluids (cold
matter, radiation) are in thermal equilibrium with the horizon. We find that
the interaction terms required for this will generally violate energy
conservation ($\sum_i Q_i=0$).


title: Charged Gravastar in a Dark Energy Universe

abstract:
  Here we constructed a charged gravastar model formed by an interior de Sitter
spacetime, a charged dynamical infinitely thin shell with an equation of state
and an exterior de Sitter-Reissner-Nordstr\"om spacetime. We find that the
presence of the charge is crucial to the stability of these structures. It can
as much favor the stability of a bounded excursion gravastar, and still
converting it in a stable gravastar, as make disappear a stable gravastar,
depending on the range of the charge considered. There is also formation of
black holes and, above certain values, the presence of the charge allows the
formation of naked singularity . This is an important example in which a naked
singularity emerges as a consequence of unstabilities of a gravastar model,
which reinforces that gravastar is not an alternative model to black hole.


title: The Muon Anomalous Magnetic Moment and the Pion Polarizability

abstract:
  We compute the charged pion loop contribution to the muon anomalous magnetic
moment $a_\mu$, taking into account the effect of the charged pion
polarizability, $(\alpha_1-\beta_1)_{\pi^+}$. We evaluate this contribution
using two different models that are consistent with the requirements of chiral
symmetry in the low-momentum regime and perturbative quantum chromodynamics in
the asymptotic region. The result increases the disagreement between the
present experimental value for $a_\mu$ and the theoretical, Standard Model
prediction by as much as $\sim 60\times 10^{-11}$, depending on the value of
$(\alpha_1-\beta_1)_{\pi^+}$ and the choice of the model. The planned
determination of $(\alpha_1-\beta_1)_{\pi^+}$ at Jefferson Laboratory will
eliminate the dominant parametric error, leaving a theoretical model
uncertainty commensurate with the error expected from planned Fermilab
measurement of $a_\mu$.


title:
Non-invasive estimation of dissipation from non-equilibrium fluctuations
  in chemical reactions

abstract:
  We show how to extract from a sufficiently long time series of stationary
fluctuations of chemical reactions an estimate of the entropy production. This
method, which is based on recent work on fluctuation theorems, is direct,
non-invasive, does not require any knowledge about the underlying dynamics, and
is applicable even when only partial information is available. We apply it to
simple stochastic models of chemical reactions involving a finite number of
states, and for this case, we study how the estimate of dissipation is affected
by the degree of coarse-graining present in the input data.


title:
Local bounds, Harnack inequality and H\"older continuity for divergence
  type elliptic equations with nonstardard growth

abstract:
  In this paper we obtain a Harnack type inequality for solutions to elliptic
equations in divergence form with non-standard $p(x)-$type growth. A model
equation is the inhomogeneous $p(x)-$laplacian. Namely, \[
\Delta_{p(x)}u:=\mbox{div}\big(|\nabla u|^{p(x)-2}\nabla
u\big)=f(x)\quad\mbox{in}\quad\Omega \] for which we prove Harnack inequality
when $f\in L^{q_0}(\Omega)$ if $\max\{1,\frac N{p_{min}}\}<q_0\le \infty$. The
constant in Harnack inequality depends on $u$ only through
$\||u|^{p(x)}\|_{L^1(\Omega)}^{p_{max}-p_{min}}$. Dependence of the constant on
$u$ is known to be necessary in the case of variable $p(x)$. As in previous
papers, log-H\"older continuity on the exponent $p(x)$ is assumed.
  We also prove that weak solutions are locally bounded and H\"older continuous
when $f\in L^{q_0(x)}(\Omega)$ with $q_0\in C(\Omega)$ and $\max\{1,\frac
N{p(x)}\}<q_0(x)$ in $\Omega$.
  These results are then generalized to elliptic equations \[
\mbox{div}A(x,u,\nabla u)=B(x,u,\nabla u) \] with $p(x)-$type growth.


title: Antiresonance phase shift in strongly coupled cavity QED

abstract:
  We investigate phase shifts in the strong coupling regime of single-atom
cavity quantum electrodynamics (QED). On the light transmitted through the
system, we observe a phase shift associated with an antiresonance and show that
both its frequency and width depend solely on the atom, despite the strong
coupling to the cavity. This shift is optically controllable and reaches 140
degrees - the largest ever reported for a single emitter. Our result offers a
new technique for the characterization of complex integrated quantum circuits.


title: Probing macroscopic realism via Ramsey correlations measurements

abstract:
  We describe a new and experimentally feasible protocol for performing
fundamental tests of quantum mechanics with massive objects. In our approach a
single two level system is used to probe the motion of a nanomechanical
resonator via multiple Ramsey interference measurements. This scheme enables
the measurement of modular variables of macroscopic continuous variable systems
and we show that correlations thereof violate a Leggett-Garg inequality and can
be applied for tests of quantum contextuality. Our method can be implemented
with a variety of different solid state or photonic qubit-resonator systems and
provides a clear experimental signature to distinguish the predictions of
quantum mechanics from those of other alternative theories at a macroscopic
scale.


title:
Nonequilibrium fluctuation theorem for systems under discrete and
  continuous feedback control

abstract:
  Without violating causality, we allow performing measurements in time reverse
process of a feedback manipulated stochastic system. As a result we come across
an entropy production due to the measurement process. This entropy production,
in addition to the usual system and medium entropy production, constitutes the
total entropy roduction of the combined system of the reservoir, the system and
the feedback controller. We show that this total entropy production of "full"
system satisfies an integrated fluctuation theorem as well as a detailed
fluctuation theorem as expected. We illustrate and verify this idea through
explicit calculation and direct simulation in two examples.


title: A restriction on centralizers in finite groups

abstract:
  For a given m>=1, we consider the finite non-abelian groups G for which
|C_G(g):<g>|<=m for every g in G\Z(G). We show that the order of G can be
bounded in terms of m and the largest prime divisor of the order of G. Our
approach relies on dealing first with the case where G is a non-abelian finite
p-group. In that situation, if we take m=p^k to be a power of p, we show that
|G|<=p^{2k+2} with the only exception of Q_8. This bound is best possible, and
implies that the order of G can be bounded by a function of m alone in the case
of nilpotent groups.


title:
Simulating Organogenesis in COMSOL: Parameter Optimization for PDE-based
  models

abstract:
  Morphogenesis is a tightly regulated process that has been studied for
decades. We are developing data-based and image-basd mechanistic models for a
range of developmental processes with a view to integrate the available
knowledge and to better understand the underlying regulatory logic. In our
previous papers on simulating organogenesis with COMSOL (German et al COMSOL
Conf Procedings 2011; Menshykau and Iber, COMSOL Conf Proceedings 2012) we
discussed methods to efficiently solve such models on static and growing
domains. A further challenge in modeling morphogenesis is the parameterization
of such models. Here we discuss COMSOL-based methods for parameter
optimization. These routines can be used to determine parameter sets, for which
the simulations reproduce experimental data and constraints. Such data is often
image based, but may also come from classical biochemical or genetic
experiments.


title: A Fair Scheduling Model for Centralized Cognitive Radio Networks

abstract:
  We formulate throughput maximizing, max-min fair, weighted max-min fair, and
proportionally fair scheduling problems for cognitive radio networks managed by
a centralized cognitive base station. We propose a very general scheduling
model accomplishing goals such as making frequency, time slot, and data rate
allocation to secondary users with possibly multiple antennas, in a
heterogenous multi-channel and multi-user scenario. Moreover, our schedulers
ensure that reliable communication between the cognitive base station and
secondary users are maintained, no collisions occur among secondary users, and
primary users in the service area of the cognitive base station are not
disturbed. Two distinctive features of our fair schedulers are that they
provide joint temporal and throughput fairness, and take throughput values
experienced by secondary users in the recent past, referred to as window size,
into account and use this information in the current scheduling decision. We
also propose a heuristic algorithm for our fair schedulers and demonstrate
through simulations that our proposed heuristic yields very close solutions to
the values obtained from the optimization softwares. Furthermore, we make
extensive simulations to evaluate our schedulers' performance in terms of both
total throughput and fairness for varying number of secondary users,
frequencies, antennas, and window size.


title: Search for top partners with charge 5e/3

abstract:
  A feasibility study of searches for top partners with charge 5e/3 at the
upgraded Large Hadron Collider is performed. The discovery potential and
exclusion limits are presented using integrated luminosities of 300 fb$^{-1}$
and 3000 fb$^{-1}$ at center-of-mass energies of 14 and 33 TeV.


title: Dynamics of the reading process of a quantum memory

abstract:
  The mechanism of extraction of information stored in a quantum memory is
studied here in detail. We consider memories containing a single excitation of
a collective atomic state, which is mapped into a single photon during the
reading process. A theory is developed for the wavepacket of the extracted
photon, leading to a simple analytical expression depending on the key
parameters of the problem, like detuning and intensity of the read field and
the number of atoms in the atomic ensemble. This theory is then compared to a
large set of experimental situations and a satisfactory quantitative agreement
is obtained. In this way, we are able to systematically study the saturation
and spectrum of the reading process, as well as clarify the role of
superradiance in the system.


title: The Cost of an Epidemic over a Complex Network: A Random Matrix Approach

abstract:
  In this paper we quantify the total economic impact of an epidemic over a
complex network using tools from random matrix theory. Incorporating the direct
and indirect costs of infection, we calculate the disease cost in the large
graph limit for an SIS (Susceptible - Infected - Susceptible) infection
process. We also give an upper bound on this cost for arbitrary finite graphs
and illustrate both calculated costs using extensive simulations on random and
real-world networks. We extend these calculations by considering the total
social cost of an epidemic, accounting for both the immunization and disease
costs for various immunization strategies and determining the optimal
immunization. Our work focuses on the transient behavior of the epidemic, in
contrast to previous research, which typically focuses on determining the
steady-state system equilibrium.


title: Perfect commuting graphs

abstract:
  We classify the finite quasisimple groups whose commuting graph is perfect
and we give a general structure theorem for finite groups whose commuting graph
is perfect.


title: Probability and the Classical/Quantum Divide

abstract:
  This paper considers the problem of distinguishing between classical and
quantum domains in macroscopic phenomena using tests based on probability and
it presents a condition on the ratios of the outcomes being the same (Ps) to
being different (Pn). Given three events, Ps/Pn for the classical case, where
there are no 3-way coincidences, is one-half whereas for the quantum state it
is one-third. For non-maximally entangled objects we find that so long as r <
5.83, we can separate them from classical objects using a probability test. For
maximally entangled particles (r = 1), we propose that the value of 5/12 be
used for Ps/Pn to separate classical and quantum states when no other
information is available and measurements are noisy.


title:
Mapping the Topological Phase Diagram of Multiband Semiconductors with
  Supercurrents

abstract:
  We show that Josephson junctions made of multiband semiconductors with strong
spin-orbit coupling carry a critical supercurrent $I_c$ that contains
information about the non-trivial topology of the system. In particular, we
find that the emergence and annihilation of Majorana bound states in the
junction is reflected in strong even-odd effects in $I_c$ at small junction
transparency. This effect allows for a mapping between $I_c$ and the
topological phase diagram of the junction, thus providing a dc measurement of
its topology.


title: Contour Manifolds and Optimal Transport

abstract:
  Describing shapes by suitable measures in object segmentation, as proposed in
[24], allows to combine the advantages of the representations as parametrized
contours and indicator functions. The pseudo-Riemannian structure of optimal
transport can be used to model shapes in ways similar as with contours, while
the Kantorovich functional enables the application of convex optimization
methods for global optimality of the segmentation functional.
  In this paper we provide a mathematical study of the shape measure
representation and its relation to the contour description. In particular we
show that the pseudo-Riemannian structure of optimal transport, when restricted
to the set of shape measures, yields a manifold which is diffeomorphic to the
manifold of closed contours. A discussion of the metric induced by optimal
transport and the corresponding geodesic equation is given.


title: Direct-coupling lensing by antisymmetric tensor monopoles

abstract:
  We discuss the effects of a direct coupling between a rank-two antisymmetric
tensor field and the Maxwell field. The coupling we consider leads to vacuum
birefringence, allowing us to place constraints on the magnitude of the tensor
field and the strength of its coupling to the Maxwell field via cosmological
birefringence measurements. For light propagating in the presence of a
topological defect solution, we find that light rays with different
polarizations will follow different trajectories; the magnitude of this
deflection is predicted to be extremely small (on the order of 10^-10
arcseconds). We discuss the plausibility of this phenomenon as a method for
detection of these monopoles, along with the applicability of our methods to
other possible couplings between the tensor field and the Maxwell field.


title:
Silicene and Germanene as prospective playgrounds for Room Temperature
  Superconductivity

abstract:
  Combining theory and certain striking phenomenology we suggest that silicene
and germanene are \textit{elemental Mott insulators} and abode of doping
induced high Tc superconductivity. In our theory, a 3 fold reduction in
silicene $\pi - \pi^*$ band width, in comparison to graphene, and short range
coulomb interactions enable Mott localization. Recent experimental results are
invoked to provide support for our Mott insulator model: i) a significant
$\pi$-band narrowing, in silicene on ZrB$_2$ seen in ARPES, ii) a
superconducting gap appearing below 35 K with a large
$\frac{2\Delta}{k_BTc}\sim$ 20 in silicene on Ag, iii) emergence of electron
like pockets at M points, on electron doping by Na adsorbent, iv) certain
coherent quantum oscillation like features exhibited by silicene transistor at
room temperatures and v) absence of Landau level splitting upto 7 Tesla and vi)
superstructures, not common in graphene but, ubiquitous in silicene. A
synthesis of the above results using theory of Mott insulator, with and without
doping, is attempted. We surmise that if competing orders are taken care of and
optimal doping achieved, superconductivity in silicene and germanene could
reach room temperature scales; our estimates of model parameters, t and J
$\sim$ 1 eV, are encouragingly high, compared to cuprates.


title: Helmholtz Decomposition of the Lagrangian Displacement

abstract:
  Lagrangian displacement field $\Psi$ is the central object in Lagrangian
perturbation theory (LPT). LPT is very successful at high redshifts, but it
performs poorly at low redshifts due to severe shell crossing. To understand
and quantify the effects of shell crossing, we extract $\Psi$ from N-body
simulation and decompose it into scalar and vector parts. We find that at late
time the power spectrum of the scalar part agrees with 1-loop results from LPT
at large scales, while the power in small scales is much suppressed due to
shell crossing. At z=0, the power spectrum of $\Psi$ is 10% lower than the
1-loop results at k = 0.1 h/Mpc. Shell crossing also generates the vector
contribution in $\Psi$, although its effect is subdominant in comparison with
the power suppression in the scalar part. At z=0, the vector part contributes
10% to the total power spectrum of $\Psi$ at k = 1 h/Mpc, while only 1% is
expected from the vector contribution in LPT. We also examine the standard LPT
recipes and some of its variants. In one of the variants, we include a power
suppression factor in the displacement potential to take into account the power
suppression in small scales after shell crossing. However, these simple
phenomenological approaches are found to yield limited improvement compared to
the standard LPT after the onset of shell crossing.


title:
Anisotropic polarization, predicted as a result of the diffraction of
  blackbody radiation at a reflective phase grating with ideal conductivity

abstract:
  In the course of analyzing the axiomatic principles that form the basis of
statistical physics, the validity of the postulate that all the isoenergetic
microstates of a closed system are equally probable was checked. This article
reports the results of numerically modelling the interaction of
thermodynamically equilibrium blackbody radiation with a reflective phase
diffraction grating that possesses ideal conductivity. Cases are found in which
anisotropy of the polarization parameters is guaranteed to appear inside a
closed volume of initially homogeneous blackbody radiation, resulting in a
formal decrease of its Boltzmann entropy as a consequence of deviation from the
microcanonical Gibbs distribution. This is apparently caused by the
discontinuous character of the change of the phase trajectories of the photons
during diffraction, which makes the physical system under consideration
nonergodic.


title: Perturbations for massive gravity theories

abstract:
  A theory of massive gravity depends on a non-dynamical 'reference metric'
f_{\mu\nu} which is often taken to be the flat Minkowski metric. In this paper
we examine the theory of perturbations on a background with metric g_{\mu\nu}
which does not coincide with the reference metric f_{\mu\nu}. We derive the
mass term for general perturbations on this background and show that it
generically is not of the form of the Fierz-Pauli mass term. We explicitly
compute it for some cosmological situations.


title: Hidden symmetries in the two-dimensional isotropic antiferromagnet

abstract:
  We discuss the two-dimensional isotropic antiferromagnet in the framework of
gauge invariance. Gauge invariance is one of the most subtle useful concepts in
theoretical physics, since it allows one to describe the time evolution of
complex physical systesm in arbitrary sequences of reference frames. All
theories of the fundamental interactions rely on gauge invariance. In Dirac's
approach, the two-dimensional isotropic antiferromagnet is subject to second
class constraints, which are independent of the Hamiltonian symmetries and can
be used to eliminate certain canonical variables from the theory. We have used
the symplectic embedding formalism developed by a few of us to make the system
under study gauge-invariant. After carrying out the embedding and Dirac
analysis, we systematically show how second class constraints can generate
hidden symmetries. We obtain the invariant second-order Lagrangian and the
gauge-invariant model Hamiltonian. Finally, for a particular choice of factor
ordering, we derive the functional Schr\"odinger equations for the original
Hamiltonian and for the first class Hamiltonian and show them to be identical,
which justifies our choice of factor ordering.


title: Low-emittance tuning at the Cornell Electron Storage Ring

abstract:
  In 2008 the Cornell Electron/Positron Storage Ring (CESR) was reconfigured
from an electron/positron collider to serve as a testbed for the International
Linear Collider (ILC) damping rings. One of the primary goals of the CESR Test
Accelerator (CesrTA) project is to develop a fast low-emittance tuning method
which scales well to large rings such as the ILC damping rings, and routinely
achieves a vertical emittance of order 10 pm at 2.085 GeV. This paper discusses
the tuning methods developed at CesrTA to achieve low-emittance conditions. One
iteration of beam-based measurement and correction requires about 10 minutes. A
minimum vertical emittance of 10.3 +3.2/-3.4(sys) +/-0.2(stat) pm has been
achieved at 2.085 GeV. In various configurations and beam energies the
correction technique routinely achieves vertical emittance around 10 pm after
correction, with RMS coupling < 0.5%. The measured vertical dispersion is
dominated by beam position monitor systematics. The propagation of
uncertainties in the emittance measurement is described in detail. Simulations
modeling the effects of magnet misalignments, BPM errors, and emittance
correction algorithm suggest the residual vertical emittance measured at the
conclusion of the tuning procedure is dominated by sources other than optics
errors and misalignments.


title:
Characterization of the International Linear Collider damping ring
  optics

abstract:
  A method is presented for characterizing the emittance dilution and dynamic
aperture for an arbitrary closed lattice that includes guide field magnet
errors, multipole errors and misalignments. This method, developed and tested
at the Cornell Electron Storage Ring Test Accelerator (CesrTA), has been
applied to the damping ring lattice for the International Linear Collider
(ILC). The effectiveness of beam based emittance tuning is limited by beam
position monitor (BPM) measurement errors, number of corrector magnets and
their placement, and correction algorithm. The specifications for damping ring
magnet alignment, multipole errors, number of BPMs, and precision in BPM
measurements are shown to be consistent with the required emittances and
dynamic aperture. The methodology is then used to determine the minimum number
of position monitors that is required to achieve the emittance targets, and how
that minimum depends on the location of the BPMs. Similarly, the maximum
tolerable multipole errors are evaluated. Finally, the robustness of each BPM
configuration with respect to random failures is explored.